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Mike-Mayer A, Lam K, Morris RP, Barghouthi AA, Travascio F, Latta LL, Lindsey RW. Posterior atlantoaxial fixation of osteoporotic odontoid fracture: biomechanical analysis of the Magerl versus harms techniques in a cadaver model. Spine J 2024; 24:1510-1516. [PMID: 38685273 DOI: 10.1016/j.spinee.2024.04.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 04/09/2024] [Accepted: 04/22/2024] [Indexed: 05/02/2024]
Abstract
BACKGROUND CONTEXT Odontoid fractures are among the most common cervical spine fractures in the elderly and are associated with increased morbidity and mortality. Clinical evidence suggests improved survival and quality of life after operative intervention compared to nonoperative treatment. PURPOSE This study seeks to examine the stability of an osteoporotic Type II odontoid fracture following posterior atlantoaxial fixation with either the Magerl transarticular fixation technique or the Harms C1 lateral mass screws C2 pedicle screw rod fixation. STUDY DESIGN Biomechanical cadaveric study. METHODS Eighteen cadaveric specimens extending from the cephalus to C7 were used in this study. Reflective marker arrays were attached to C1 and C2 and a single marker on the dens to measure movement of each during loading with C2-C3 and occiput-C1 being allowed to move freely. A biomechanical testing protocol imparted moments in flexion-extension, axial rotation, and lateral bending while a motion capture system recorded the motions of C1, C2, and the dens. The spines were instrumented with either the Harms fixation (n=9) or Magerl fixation (n=9) techniques, and a simulated Type II odontoid fracture was created. Motions of each instrumented spine were recorded for all moments, and then again after the instrumentation was removed to model the injured, noninstrumented state. RESULTS Both Harms and Magerl posterior C1-C2 fixation allowed for C1, C2, and the dens to move as a relative unit. Without fixation the dens motion was coupled with C1. No significant differences were found in X, Y, Z translation motion of the dens, C1 or C2 during neutral zone motions between the Magerl and Harms fixation techniques. There were no significant differences found in Euler angle motion between the two techniques in either flexion-extension, axial rotation, or lateral bending motion. CONCLUSIONS Our findings suggest that both Harms and Magerl fixation can significantly reduce dens motion in Type II odontoid fractures in an osteoporotic cadaveric bone model. CLINICAL SIGNIFICANCE Both Harms and Magerl posterior atlantoaxial fixation techniques allowed for C1, C2, and the dens to move as a relative unit following odontoid fracture, establishing more anatomic stability to the upper cervical spine.
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Affiliation(s)
- Austin Mike-Mayer
- The Department of Orthopedic Surgery and Rehabilitation, The University of Texas Medical Branch, 301 University Blvd., Galveston, TX, USA
| | - Kendrick Lam
- Mount Sinai Medical Center, Max Biedermann Institute for Biomechanics, 4300 Alton Rd., Miami Beach, FL, USA
| | - Randal P Morris
- The Department of Orthopedic Surgery and Rehabilitation, The University of Texas Medical Branch, 301 University Blvd., Galveston, TX, USA.
| | - Abeer Al Barghouthi
- Mount Sinai Medical Center, Max Biedermann Institute for Biomechanics, 4300 Alton Rd., Miami Beach, FL, USA
| | - Francesco Travascio
- Mount Sinai Medical Center, Max Biedermann Institute for Biomechanics, 4300 Alton Rd., Miami Beach, FL, USA; Department of Mechanical and Aerospace Engineering, University of Miami, 1251 Memorial Dr., Coral Gables, FL, USA; Department of Orthopaedics, University of Miami, 1611 NW 12th Ave #303, Miami, FL, USA
| | - Loren L Latta
- Mount Sinai Medical Center, Max Biedermann Institute for Biomechanics, 4300 Alton Rd., Miami Beach, FL, USA; Department of Orthopaedics, University of Miami, 1611 NW 12th Ave #303, Miami, FL, USA
| | - Ronald W Lindsey
- The Department of Orthopedic Surgery and Rehabilitation, The University of Texas Medical Branch, 301 University Blvd., Galveston, TX, USA
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Fiorenza V, Ascanio F, Brunasso L, Lo Duca B, Fimognari AM, Grippi L, Giovannini EA, Maugeri R, Iacopino DG. Nuance in Craniovertebral Junction Surgical Approach for Posterior C1-C2 Harms Stabilization: "Window Transposition" of the External Vertebral Venous Plexus for Bloodless C1 Lateral Mass Screw Insertion: Anatomical Aspects and Technical Notes. ACTA NEUROCHIRURGICA. SUPPLEMENT 2023; 135:307-313. [PMID: 38153486 DOI: 10.1007/978-3-031-36084-8_47] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Atlas and axis instrumentation may be necessary in cases of several craniocervical junction pathologies. According to the Harms technique, C1-C2 polyaxial screws are inserted respectively in the C1 lateral masses and in C2 pedicles. C1 lateral mass screw insertion requires the careful subperiosteal dissection of the posterior elements of C1, the identification of the screw entry point by the downward distraction of C2 nerve root, and the cautious sparing of the overlying posterior external vertebral venous plexus (peVVP), whose bleeding, obstructing the surgical field, is sometimes barely controlled by hemostatic agents and swabbing. The authors describe in detail the anatomical aspects of an alternative surgical technique developed for the microsurgical transposition of the C1-C2 interposed external vertebral venous plexus in the case of Harms C1-C2 screw stabilization. The longitudinal median incision of the atlantoaxial membrane, followed by bilateral subperiosteal dissection and microsurgical section respectively at the inferior borders of the C1 laminae and at the superior borders of the C2 laminae, allows, as a "window opening," the symmetrical mediolateral transposition of the peVVP. This procedure provides a faster and cleaner anatomical exposition of the posterior surface of the C1 lateral mass and the C2 isthmus, preventing troublesome intraoperative venous bleeding that hinders C1 lateral mass screw insertion.
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Affiliation(s)
- Vito Fiorenza
- U.O.C. Neurochirurgia, Dipartimento Testa-Collo, A.R.N.A.S. Civico-Di Cristina-Benfratelli, Palermo, Italy
| | - Francesco Ascanio
- U.O.C. Neurochirurgia, Dipartimento Testa-Collo, A.R.N.A.S. Civico-Di Cristina-Benfratelli, Palermo, Italy
| | - Lara Brunasso
- Department of Experimental Biomedicine and Clinical Neurosciences, School of Medicine, Postgraduate Residency Program in Neurologic Surgery, Neurosurgical Clinic, AOUP "Paolo Giaccone", University of Palermo, Palermo, Italy
| | - Benedetto Lo Duca
- U.O.C. Neurochirurgia, Dipartimento Testa-Collo, A.R.N.A.S. Civico-Di Cristina-Benfratelli, Palermo, Italy
| | - Anna Maria Fimognari
- U.O.C. Neurochirurgia, Dipartimento Testa-Collo, A.R.N.A.S. Civico-Di Cristina-Benfratelli, Palermo, Italy
| | - Luisa Grippi
- U.O.C. Neurochirurgia, Dipartimento Testa-Collo, A.R.N.A.S. Civico-Di Cristina-Benfratelli, Palermo, Italy
| | - Evier Andrea Giovannini
- Department of Experimental Biomedicine and Clinical Neurosciences, School of Medicine, Postgraduate Residency Program in Neurologic Surgery, Neurosurgical Clinic, AOUP "Paolo Giaccone", University of Palermo, Palermo, Italy
| | - Rosario Maugeri
- Department of Experimental Biomedicine and Clinical Neurosciences, School of Medicine, Postgraduate Residency Program in Neurologic Surgery, Neurosurgical Clinic, AOUP "Paolo Giaccone", University of Palermo, Palermo, Italy
| | - Domenico Gerardo Iacopino
- Department of Experimental Biomedicine and Clinical Neurosciences, School of Medicine, Postgraduate Residency Program in Neurologic Surgery, Neurosurgical Clinic, AOUP "Paolo Giaccone", University of Palermo, Palermo, Italy
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Lin Y, Rao S, Liu B, Sun Y, Zhao S, Su G, Chen S, Li Y, Chen B. Percutaneous full endoscopic C1 laminectomy for developmental atlantal stenosis with myelopathy: a case report of three cases and review of the literature. ANNALS OF TRANSLATIONAL MEDICINE 2022; 10:720. [PMID: 35845524 PMCID: PMC9279768 DOI: 10.21037/atm-22-2282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 06/01/2022] [Indexed: 11/30/2022]
Abstract
Background Developmental atlantal stenosis with myelopathy (DASM) in adults is a rare disease that only sporadic cases have been reported over the years. C1 laminectomy (C1L) is one of the most common operations for its treatment. However, as an open surgery, it has shortcomings such as large trauma and slow postoperative rehabilitation, and minimally invasive spine surgery (MISS) offers alternative treatment options with advantages. MISS instruments expand the technical capabilities of surgeons, which allows safer and more effective therapeutics for difficult and complicated diseases. This case report presents a new minimally invasive approach; percutaneous full endoscopic C1 laminectomy (PFEC1L), for the treatment of DASM, and to consolidate the current literature on the condition to summarize its etiologies, clinical manifestations, diagnostic criteria, surgical management, and prognoses. Case Description The patient in Case 1 presented with neck pain and numbness and weakness in the limbs. The patient in Case 2 presented with numbness in the extremities and the patient in Case 3 presented with bilateral hand numbness and left lower limb weakness. They were all diagnosed with DASM and underwent PFEC1L treatment to maintain the enlargement and decompression of the atlantal canal, which achieved favorable outcomes without complications during the postoperative follow-up visit. Conclusions DASM is rare but potentially dangerous. Its diagnosis is made based on clinical manifestations combined with radiological imaging examinations, especially computed tomography (CT) scan and magnetic resonance imaging (MRI). While C1L is the most common surgical method, PFEC1L is a new feasible and safe therapeutic option with comparable good outcomes and the advantage of being minimally-invasive. To our knowledge this is the first report that PFEC1L was applied for DASM treatment.
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Affiliation(s)
- Yongpeng Lin
- Division of Spine Center, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangzhou, China.,Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Siyuan Rao
- Division of Spine Center, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangzhou, China.,Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Bingxin Liu
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yueli Sun
- Spine Disease Institute, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Shuai Zhao
- Division of Spine Center, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangzhou, China.,Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Guoyi Su
- Division of Spine Center, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangzhou, China.,Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Shudong Chen
- Division of Spine Center, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangzhou, China.,Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yongjin Li
- Division of Spine Center, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangzhou, China.,Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Bolai Chen
- Division of Spine Center, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangzhou, China.,Guangzhou University of Chinese Medicine, Guangzhou, China
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Lee HR, Lee DH, Cho JH, Hwang ES, Seok SY, Park S, Lee CS. Feasibility of lateral mass screw insertion in patients with the risky triad of C1: evaluation of the over-the-arch technique. J Neurosurg Spine 2022; 36:822-829. [PMID: 34826808 DOI: 10.3171/2021.8.spine21695] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 08/24/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The objective of this study was to evaluate the feasibility and complications of the over-the-arch (OTA) technique for screw insertion into the C1 lateral mass in patients in whom conventional techniques (i.e., posterior arch [PA] and inferior lateral mass [ILM]) are not feasible due to 1) PA with a very small height (< 3.5 mm), 2) a caudally tilted PA blocking the inferior part of the C1 lateral mass, or 3) loss of height at the ILM (< 3.5 mm). METHODS The authors reviewed the medical records of 60 patients who underwent C1 screw fixation with the OTA technique (13 screws) and the PA/ILM technique (107 screws) between 2011 and 2019. Vertebral artery (VA) injuries, screw malposition, and bony union were radiologically assessed. Clinical outcome measures, including Neck Disability Index (NDI), Japanese Orthopaedic Association (JOA) scale score, and occipital neuralgia, were recorded. RESULTS Thirteen OTA screws were successfully inserted without any major complications. NDI and JOA scale scores did not show significant differences between the two groups at final follow-up. No VA injuries were recognized during screw insertion. There was no evidence of ischemic damage to the VA or bony erosion in the occiput or atlas. Medial wall violation was observed in 1 screw (7.7%); however, no C0-1, C1-2, or lateral wall violations were observed. No patients developed new-onset neuralgia postoperatively after C1 fixation with the OTA technique. CONCLUSIONS The OTA technique was safe and useful for C1 screw fixation in patients in whom conventional techniques could not be employed.
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Affiliation(s)
- Hyung Rae Lee
- 1Department of Orthopedic Surgery, Uijeongbu Eulji Medical Center, Uijeongbusi, Republic of Korea
| | - Dong-Ho Lee
- 2Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jae Hwan Cho
- 2Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Eui Seung Hwang
- 3College of Art and Science, Emory University, Atlanta, Georgia
| | - Sang Yun Seok
- 4Department of Orthopedic Surgery, Daejeon Eulji Medical Center, Daejeon, Republic of Korea; and
| | - Sehan Park
- 5Department of Orthopedic Surgery, Dongguk University Ilsan Hospital, Goyangsi, Republic of Korea
| | - Choon Sung Lee
- 2Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
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Bunmaprasert T, Puangkaew W, Sugandhavesa N, Liawrungrueang W, Riew KD. The Intersection Between Lateral Mass and Inferomedial Edge of the C1 Posterior Arch: A Reference Point for C1 Lateral Mass Screw Insertion. Neurospine 2021; 18:328-335. [PMID: 34218613 PMCID: PMC8255764 DOI: 10.14245/ns.2040814.407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 02/18/2021] [Indexed: 11/19/2022] Open
Abstract
Objective To determine the ideal Atlas (C1) lateral mass screw placement and trajectory using the intersection between the lateral mass and inferomedial edge of the posterior arch as an easily identifiable and reproducible medial reference point. Selection of an ideal entry point and trajectory of C1 lateral mass screw insertion can help to minimize neurovascular injuries. While various techniques for screw insertion have been proposed in the past, they all require extensive dissection of the C1 lateral mass, which can cause profuse bleeding.
Methods Ninety-three 3-dimensional computed tomography reconstructed images of C1 lateral masses in adult patients were utilized to simulate the placement of C1 lateral mass screws via 4 entry points and 2 trajectory angles referencing off of a medial reference point using Vero’s VISI 17 software. The safety during screw insertion simulation, as well as the screw length, were evaluated.
Results We found that C1 lateral mass screws could be safely placed bilaterally at 3 mm lateral to the reference point in both 0° and 15° medial screw angulation without violation of the cortex. The 15° medial angulation allowed for longer (18 mm) screws than the 0° angulation.
Conclusion We recommend starting C1 lateral mass screws 3 mm lateral to the intersection between the lateral mass and inferomedial edge of the posterior arch at a 15° medial angulation.
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Affiliation(s)
- Torphong Bunmaprasert
- Department of Orthopaedics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Watcharapong Puangkaew
- Department of Orthopaedics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Nantawit Sugandhavesa
- Department of Orthopaedics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | | | - K Daniel Riew
- Department of Orthopedic Surgery, NewYork-Presbyterian Och Spine Hospital/Columbia University Irving Medical Center, New York, NY, USA
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Chen Q, Brahimaj BC, Khanna R, Kerolus MG, Tan LA, David BT, Fessler RG. Posterior atlantoaxial fusion: a comprehensive review of surgical techniques and relevant vascular anomalies. JOURNAL OF SPINE SURGERY 2020; 6:164-180. [PMID: 32309655 DOI: 10.21037/jss.2020.03.05] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Posterior atlantoaxial fusion is an important surgical technique frequently used to treat various pathologies involving the cervical 1-2 joint. Since the beginning of the 20th century, various fusion techniques have been developed with improved safety profile, higher fusion rates, and superior clinical outcome. Despite the advancement of technology and surgical techniques, posterior C1-2 fusion is still a technically challenging procedure given the complex bony and neurovascular anatomy in the craniovertebral junction (CVJ). In addition, vascular anomalies in this region are not uncommon and can lead to devastating neurovascular complications if unrecognized. Thus, it is important for spine surgeons to be familiar with various posterior atlantoaxial fusion techniques along with a thorough knowledge of various vascular anomalies in the CVJ. Intimate knowledge of the various surgical techniques in combination with an appreciation for anatomical variances, allows the surgeon develop a customized surgical plan tailored to each patient's particular pathology and individual anatomy. In this article, we aim to provide a comprehensive review of existing posterior C1-2 fusion techniques along with a review of common vascular anomalies in the CVJ.
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Affiliation(s)
- Qi Chen
- Department of Neurosurgery, Rush University Medical Center, Chicago, IL, USA
| | - Bledi C Brahimaj
- Department of Neurosurgery, Rush University Medical Center, Chicago, IL, USA
| | - Ryan Khanna
- Department of Neurosurgery, Rush University Medical Center, Chicago, IL, USA
| | - Mena G Kerolus
- Department of Neurosurgery, Rush University Medical Center, Chicago, IL, USA
| | - Lee A Tan
- Department of Neurosurgery, UCSF Medical Center, San Francisco, CA, USA
| | - Brian T David
- Department of Neurosurgery, Rush University Medical Center, Chicago, IL, USA
| | - Richard G Fessler
- Department of Neurosurgery, Rush University Medical Center, Chicago, IL, USA
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Caglar S, Turkoglu E, Kertmen H, Gurer B, Bozkurt H, Ozay R, Hanalioglu S, Colpan E. Modified Inside-outside Occipito-Cervical Plate System: Preliminary Results. Asian J Neurosurg 2019; 14:148-153. [PMID: 30937026 PMCID: PMC6417361 DOI: 10.4103/ajns.ajns_305_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Context: Internal rigid fixation provides immediate stability of the occipito-cervical (OC) junction for treatment of instability; however, in current practice, the optimal OC junction stabilization method is debatable. Aims: The aim of this study to test the safety and efficacy of a newly designed modified inside-outside occipito-cervical (MIOOC) plate system for the treatment of instability. Settings and Design: This was a feasibility study of MIOCC plate system. Subjects and Methods: Five male and four female patients with OC instability were treated using MIOOC plate system. Stabilization rate, safety, and efficacy were evaluated radiologically and clinically. Results: Mean age of the patients was 35 ± 11 (range: 22–58) years. Etiology of OC instability included trauma, neoplasm, congenital abnormalities, and iatrogenic. The fusion levels ranged from occiput-C3 to occiput-C6. Mean follow-up duration was 22 ± 10 (range: 6–46) months. There were neither complication nor was there any need for plate revision or screw pullout. Mortality occurred in one patient due to primary malignancy at 6 months; otherwise, no morbidity was observed. During the follow-up, no recurrent subluxation or newly developed instability at adjacent levels occurred. All patients showed a satisfactory union at the most recent follow-up examination. Conclusions: These preliminary results suggest that the MIOCC plate system is a useful and safe method for providing immediate internal stability of the OC junction. Using a multi-piece plate design in this plate system provided easy implantation and a better interface between plate and OC bones. Further, clinical studies and long-term results are needed to determine the reliability of the MIOOC plate system.
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Affiliation(s)
- Sukru Caglar
- Department of Neurosurgery, Ankara University, School of Medicine, Ankara, Turkey
| | - Erhan Turkoglu
- Department of Neurosurgery, University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Neurosurgery Clinic, Ankara, Turkey
| | - Hayri Kertmen
- Department of Neurosurgery, University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Neurosurgery Clinic, Ankara, Turkey
| | - Bora Gurer
- Department of Neurosurgery, Ministry of Health, University of Health Sciences, Fatih Sultan Mehmet Training and Research Hospital, Neurosurgery Clinic, Istanbul, Turkey
| | - Huseyin Bozkurt
- Department of Neurosurgery, Cumhuriyet University, School of Medicine, Sivas, Turkey
| | - Rafet Ozay
- Department of Neurosurgery, University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Neurosurgery Clinic, Ankara, Turkey
| | - Sahin Hanalioglu
- Department of Neurosurgery, University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Neurosurgery Clinic, Ankara, Turkey
| | - Efkan Colpan
- Department of Neurological Surgery, UPMC Hamot, Erie, PA, USA
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Mizutani J, Inoue N, Otsuka Y, Furuya A, Espinoza Orias AA, Otsuka T. Biomechanical and Anatomical Validity of the Short Posterior Arch Screw. Neurospine 2018; 16:347-353. [PMID: 30653910 PMCID: PMC6603827 DOI: 10.14245/ns.1836156.078] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 08/31/2018] [Indexed: 01/05/2023] Open
Abstract
Objective This study was conducted to clarify the validity of the short posterior arch screw (S-PAS). The S-PAS is inserted only in the pedicle-analogue portion of the posterior arch. The S-PAS screw length is almost half that conventional C1 lateral mass screws inserted via the posterior arch (via-PAS). S-PAS reduces the risk of vertebral artery injury (VAI) because it never reaches the transverse foramen. Although the biomechanical validity of various C1 lateral mass screws (C1LMS) analyzed in young specimens have been published, that of unicortically inserted C1LMS such as the unicortical Harms screw, S-PAS, and via-PAS for elderly patients is concerning because of the high prevalence of osteoporosis in the elderly.
Methods Nine fresh frozen cadavers (average age at death, 72.1 years) were used for pullout testing. The bone mineral density of each specimen was evaluated using quantitative computed tomography.
Results The pullout strength of via-PAS (1,048.5 N) was significantly greater than that of the unicortical Harms screw (257.9 N) (p<0.05). The pullout strength of S-PAS was 720.3 N, which was also significantly greater than that of the unicortical Harms screw (p<0.05).
Conclusion The via-PAS and S-PAS are valid surgical options, even in elderly patients. Along with sufficient biomechanical strength, the S-PAS screw prevents VAI.
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Affiliation(s)
- Jun Mizutani
- Department of Orthopaedic Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Nozomu Inoue
- Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA
| | - Yoshihisa Otsuka
- Department of Orthopaedic Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Aiharu Furuya
- Department of Orthopaedic Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | | | - Takanobu Otsuka
- Department of Orthopaedic Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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Biomechanical Comparison of Four Different Atlantoaxial Posterior Fixation Constructs in Adults: A Finite Element Study. Spine (Phila Pa 1976) 2018; 43:E891-E897. [PMID: 29462065 DOI: 10.1097/brs.0000000000002584] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Finite element analysis. OBJECTIVE To compare the biomechanical stability imparted to the C1 and C2 vertebrae by the transarticular (TA), C1 lateral mass (LM)-C2 pedicle (PS), C1LM-C2 pars, and C1LM-C2 translaminar (TL) screw fixation techniques. SUMMARY OF BACKGROUND DATA Cadaveric biomechanical studies of several atlantoaxial posterior fixation techniques have been performed, showing significant heterogeneity in biomechanical properties among the studies. METHODS From computed tomography images, a nonlinear intact three-dimensional C1-2 finite element model was developed and validated. Four finite element models were reconstructed from different C1-2 fixation techniques. The range of motion (ROM) and maximum von Misses stresses for the four screw techniques were compared under flexion, extension, lateral bending, and axial rotation. RESULTS C1LM-C2PS showed the greatest decrease in ROM with flexion/extension and lateral bending. C1-2TA and C1LM-C2 pars showed less ROM reduction than the other techniques, in flexion/extension. C1LM-C2TL showed the least decrease in ROM during axial rotation. For C1-2TA, the maximum stress was in the C1-2 joint region. In the C1LM-C2PS, the C1 rod head, C2 pars screw, and C2TL screw were stressed at the C2 rod head. The maximal von Mises stress on the C1-2TA at the C1-2 joint site was the highest at flexion/extension, whereas the C1LM-C2PS had the lowest stress on the screw at flexion/extension and lateral bending. The C1LM-C2TL showed the highest stress in axial rotation and lateral bending. CONCLUSION In this study, C1LM-C2PS fixation was the most stable technique. If surgeons have to use other fixation methods besides the C2 pedicle screw, they need to be aware that additional fixation or postoperative immobilization may be required to achieve ROM restriction. Careful observation at the maximum stress site on the screw including screw loosening, screw-bone interface disruption or screw fracture will be necessary during follow-up imaging examinations (x-ray and computed tomography scan) after atlantoaxial fixation. LEVEL OF EVIDENCE N/A.
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Dusad T, Kundnani V, Dutta S, Patel A, Mehta G, Singh M. Minimally Invasive Microscope-Assisted Stand-Alone Transarticular Screw Fixation without Gallie Supplementation in the Management of Mobile Atlantoaxial Instability. Asian Spine J 2018; 12:710-719. [PMID: 30060381 PMCID: PMC6068403 DOI: 10.31616/asj.2018.12.4.710] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/21/2017] [Indexed: 11/23/2022] Open
Abstract
Study Design Retrospective study. Purpose To evaluate the clinico-radiological efficacy of stand-alone minimally invasive transarticular screw (MIS-TAS) fixation without supplemental Gallie fixation in the management of mobile C1–C2 instability. Overview of Literature Data evaluating the efficacy and feasibility of MIS-TAS in the literature is scanty. Methods Patients with mobile atlantoaxial instability and >2 years follow-up were included and managed by stand-alone TAS fixation using the Magerl technique and morselized allograft without additional fixation. Patient demographics and intra-operative parameters were noted. Clinical parameters (Visual Analog Scale [VAS] and Oswestry Disability Index [ODI]), neurology (modified Japanese Orthopaedic Association [mJOA]), and radiological factors (anterior atlanto-dens interval and space available for cord) were evaluated pre and postoperatively. Computed tomography (CT) was performed in patients who did not show interspinous fusion on X-ray at 1 year, to verify intra-articular fusion. Statistical analysis was performed using IBM SPSS ver. 20.0 (IBM Corp., Armonk, NY, USA); the Student t-test and analysis of variance were used to assess statistical significance (p <0.05). Results A total of 82 consecutive cases (three males, one female; mean age, 36.26±5.78 years) were evaluated. In total, 163 TASs were placed. Significant improvement was noticed in clinical (mean preoperative VAS=7.2±2.19, postoperative VAS=3.3±1.12; mean preoperative ODI=78.3±4.83, postoperative ODI=34.05±3.26) and neurological features (mean preoperative mJOA=14.73±2.68, postoperative mJOA=17.5±2.21). Radiological evidence of fusion was noted in 97.5% cases at final follow-up. Seventeen patients were found to have no interspinous fusions upon X-rays, but CT revealed facet fusion in all patients except in two. Inadvertent vertebral artery injury was noted in three cases. Conclusions Stand-alone TAS fixation with morselized allograft provides excellent radiological and clinical outcomes. The addition of a supplementary tension band and structural graft are not essential. This provides the opportunity to avoid the complications associated with graft harvesting and wiring.
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Affiliation(s)
- Tarun Dusad
- Department of Orthopaedics, Bombay Hospital & Medical Research Centre, Mumbai, India
| | - Vishal Kundnani
- Department of Orthopaedics, Bombay Hospital & Medical Research Centre, Mumbai, India
| | - Shumayou Dutta
- Department of Orthopaedics, Bombay Hospital & Medical Research Centre, Mumbai, India
| | - Ankit Patel
- Department of Orthopaedics, Bombay Hospital & Medical Research Centre, Mumbai, India
| | - Gaurav Mehta
- Department of Orthopaedics, Bombay Hospital & Medical Research Centre, Mumbai, India
| | - Mahendra Singh
- Department of Orthopaedics, Bombay Hospital & Medical Research Centre, Mumbai, India
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Herzog JP, Zarkadis NJ, Prabhakar G, Kusnezov NA. Biomechanical comparison of a novel C1 posterior U-construct with four other techniques in a C1-C2 fixation model. J Orthop 2018; 15:741-745. [PMID: 29881231 DOI: 10.1016/j.jor.2018.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 05/06/2018] [Indexed: 11/16/2022] Open
Abstract
Background Compare the biomechanical stability of a novel "U" posterior cervical fixation construct to four other posterior cervical atlantoaxial fixation constructs. Methods Eight fresh frozen human cadaver spines were tested after a simulated odontoid fracture, and following stabilization with each construct. Results All constructs significantly decreased flexion-extension and axial rotation compared to the destabilized spine. The U construct provided significantly more axial stability than the Brooks wire technique. Conclusion The novel U construct demonstrated comparable biomechanical stability to the existing constructs in all three planes of motion with the exception of axial rotation, in which it was inferior to TAS.
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Affiliation(s)
- Joshua P Herzog
- Orthopaedic Spine Center, Massachusetts General Hospital, Boston, MA, United States
| | - Nicholas J Zarkadis
- Department of Orthopaedic Surgery and Rehabilitation, William Beaumont Army Medical Center, El Paso, TX, United States
| | - Gautham Prabhakar
- Paul L. Foster School of Medicine at Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
| | - Nicholas A Kusnezov
- Department of Orthopaedic Surgery and Rehabilitation, William Beaumont Army Medical Center, El Paso, TX, United States
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12
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Advantages of an on-the-screwhead crosslink connector for atlantoaxial fixation using the Goel/Harms technique. J Clin Neurosci 2018; 50:183-189. [DOI: 10.1016/j.jocn.2018.01.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 01/08/2018] [Indexed: 11/20/2022]
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13
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Liu N, Tian L, Jiang RX, Xu C, Shi L, Lei W, Zhang Y. An in vitro biomechanical evaluation of an expansive double-threaded bi-directional compression screw for fixation of type II odontoid process fractures: A SQUIRE-compliant article. Medicine (Baltimore) 2017; 96:e6720. [PMID: 28422889 PMCID: PMC5406106 DOI: 10.1097/md.0000000000006720] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Odontoid process fracture accounts for 5% to 15% of all cervical spine injuries, and the rate is higher among elderly people. The anterior cannulated screw fixation has been widely used in odontoid process fracture, but the fixation strength may still be limited under some circumstances. This study aims to investigate the biomechanical fixation strength of expansive double-threaded bi-directional compression screw (EDBCS) compared with cannulated lag screw (CLS) and improved Herbert screw (IHS) for fixation of type II odontoid process fracture.Thirty fresh cadaveric C2 vertebrae specimens were harvested and randomly divided into groups A, B, and C. A type II fracture model was simulated by osteotomy. Then the specimens of the 3 groups were stabilized with a single CLS, IHS, or EDBCS, respectively. Each specimen was tested in torsion from 0° to 1.25° for 75 s in each of 5 cycles clockwise and 5 cycles anticlockwise. Shear and tensile forces were applied at the anterior-to-posterior and proximal-to-distal directions, respectively, both to a maximum load of 45 N and at a speed of 1 mm/min.The mean torsional stiffness was 0.309 N m/deg for IHS and 0.389 N m/deg for EDBCS, which were significantly greater compared with CLS, respectively (0.169 N m/deg) (P < .05 and P < .05). The mean shear stiffness for the EDBCS was 238 N/mm, which was significantly greater than CLS (150 N/mm) and IHS (132 N/mm) (P < .05 and P < .05). All 3 screws only partly restored tensile stiffness, but not significantly.Fixation with the EDBCS can improve the biomechanical strength for odontoid process fracture compared with CLS and IHS, especially in terms of torsional and shear stiffness.
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Affiliation(s)
- Ning Liu
- Department of Orthopedics, Xijing Hospital, The Fourth Military Medical University
| | - Li Tian
- Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi’an
| | - Rong-Xian Jiang
- Department of Orthopedics, 62th Hospital of PLA, Puer, China
| | - Chao Xu
- Department of Orthopedics, Xijing Hospital, The Fourth Military Medical University
| | - Lei Shi
- Department of Orthopedics, Xijing Hospital, The Fourth Military Medical University
| | - Wei Lei
- Department of Orthopedics, Xijing Hospital, The Fourth Military Medical University
| | - Yang Zhang
- Department of Orthopedics, Xijing Hospital, The Fourth Military Medical University
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Accuracy Assessment of Using Rapid Prototyping Drill Templates for Atlantoaxial Screw Placement: A Cadaver Study. BIOMED RESEARCH INTERNATIONAL 2016; 2016:5075879. [PMID: 28004004 PMCID: PMC5149599 DOI: 10.1155/2016/5075879] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 10/05/2016] [Indexed: 11/23/2022]
Abstract
Purpose. To preliminarily evaluate the feasibility and accuracy of using rapid prototyping drill templates (RPDTs) for C1 lateral mass screw (C1-LMS) and C2 pedicle screw (C2-PS) placement. Methods. 23 formalin-fixed craniocervical cadaver specimens were randomly divided into two groups. In the conventional method group, intraoperative fluoroscopy was used to assist the screw placement. In the RPDT navigation group, specific RPDTs were constructed for each specimen and were used intraoperatively for screw placement navigation. The screw position, the operating time, and the fluoroscopy time for each screw placement were compared between the 2 groups. Results. Compared with the conventional method, the RPDT technique significantly increased the placement accuracy of the C2-PS (p < 0.05). In the axial plane, using RPDTs also significantly increased C1-LMS placement accuracy (p < 0.05). In the sagittal plane, although using RPDTs had a very high accuracy rate (100%) in C1-LMS placement, it was not statistically significant compared with the conventional method (p > 0.05). Moreover, the RPDT technique significantly decreased the operating and fluoroscopy times. Conclusion. Using RPDTs significantly increases the accuracy of C1-LMS and C2-PS placement while decreasing the screw placement time and the radiation exposure. Due to these advantages, this approach is worth promoting for use in the Harms technique.
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15
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Comparison of outcomes after atlantoaxial fusion with C1 lateral mass–C2 pedicle screws and C1–C2 transarticular screws. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2016; 26:1064-1072. [DOI: 10.1007/s00586-016-4829-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 09/09/2016] [Accepted: 10/16/2016] [Indexed: 11/25/2022]
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Smith JD, Jack MM, Harn NR, Bertsch JR, Arnold PM. Screw Placement Accuracy and Outcomes Following O-Arm-Navigated Atlantoaxial Fusion: A Feasibility Study. Global Spine J 2016; 6:344-9. [PMID: 27190736 PMCID: PMC4868588 DOI: 10.1055/s-0035-1563723] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 07/20/2015] [Indexed: 12/29/2022] Open
Abstract
Study Design Case series of seven patients. Objective C2 stabilization can be challenging due to the complex anatomy of the upper cervical vertebrae. We describe seven cases of C1-C2 fusion using intraoperative navigation to aid in the screw placement at the atlantoaxial (C1-C2) junction. Methods Between 2011 and 2014, seven patients underwent posterior atlantoaxial fusion using intraoperative frameless stereotactic O-arm Surgical Imaging and StealthStation Surgical Navigation System (Medtronic, Inc., Minneapolis, Minnesota, United States). Outcome measures included screw accuracy, neurologic status, radiation dosing, and surgical complications. Results Four patients had fusion at C1-C2 only, and in the remaining three, fixation extended down to C3 due to anatomical considerations for screw placement recognized on intraoperative imaging. Out of 30 screws placed, all demonstrated minimal divergence from desired placement in either C1 lateral mass, C2 pedicle, or C3 lateral mass. No neurovascular compromise was seen following the use of intraoperative guided screw placement. The average radiation dosing due to intraoperative imaging was 39.0 mGy. All patients were followed for a minimum of 12 months. All patients went on to solid fusion. Conclusion C1-C2 fusion using computed tomography-guided navigation is a safe and effective way to treat atlantoaxial instability. Intraoperative neuronavigation allows for high accuracy of screw placement, limits complications by sparing injury to the critical structures in the upper cervical spine, and can help surgeons make intraoperative decisions regarding complex pathology.
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Affiliation(s)
- Jacob D. Smith
- School of Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States
| | - Megan M. Jack
- Department of Neurosurgery, University of Kansas Medical Center, Kansas City, Kansas, United States
| | - Nicholas R. Harn
- Department of Radiology, University of Kansas Medical Center, Kansas City, Kansas, United States
| | - Judson R. Bertsch
- Department of Radiology, University of Kansas Medical Center, Kansas City, Kansas, United States
| | - Paul M. Arnold
- Department of Neurosurgery, University of Kansas Medical Center, Kansas City, Kansas, United States,Address for correspondence Paul M. Arnold, MD Department of Neurosurgery, Mail Stop 3021, University of Kansas Medical Center3901 Rainbow Blvd., Kansas City, KS 66160United States
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17
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Evaluation of the Efficacy of Titanium Mesh Cages with Posterior C1 Lateral Mass and C2 Pedicle Screw Fixation in Patients with Atlantoaxial Instability. World Neurosurg 2016; 90:103-108. [DOI: 10.1016/j.wneu.2016.02.087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 11/21/2022]
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Menger RP, Storey CM, Nixon MKC, Haydel J, Nanda A, Sin A. Placement of C1 Pedicle Screws Using Minimal Exposure: Radiographic, Clinical, and Literature Validation. Int J Spine Surg 2015; 9:43. [PMID: 26484006 DOI: 10.14444/2043] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Traditional C1-2 fixation involves placement of C1 lateral mass screws. Evolving techniques have led to the placement of C1 pedicle screws to avoid exposure of the C1-C2 joint capsule. Our minimal dissection technique utilizes anatomical landmarks with isolated exposure of C2 and the inferior posterior arch of C1. We evaluate this procedure clinically and radiographically through a technical report. METHODS Consecutive cases of cranial-vertebral junction surgery were reviewed for one fellowship trained spinal surgeon from 2008-2014. Information regarding sex, age, indication for surgery, private or public hospital, intra-operative complications, post-operative neurological deterioration, death, and failure of fusion was extracted. Measurement of pre-operative axial and sagittal CT scans were performed for C1 pedicle width and C1 posterior arch height respectively. RESULTS 64 patients underwent posterior cranio-vertebral junction fixation surgery. 40 of these patients underwent occipital-cervical fusion procedures. 7/9 (77.8%) C1 instrumentation cases were from trauma with the remaining two (22.2%) from oncologic lesions. The average blood loss among isolated C1-C2 fixation was 160cc. 1/9 patients (11.1%) suffered pedicle breech requiring sub-laminar wiring at the C1 level. On radiographic measurement, the average height of the C1 posterior arch was noted at 4.3mm (range 3.8mm to 5.7mm). The average width of the C1 pedicle measured at 5.3mm (range 2.8 to 8.7mm). The patient with C1 pedicle screw failure had a pedicle width of 2.78mm on pre-operative axial CT imaging. CONCLUSION Our study directly adds to the literature with level four evidence supporting a minimal dissection of C1 arch in the placement of C1 pedicle screws with both radiographic and clinical validation. CLINICAL RELEVANCE Justification of this technique avoids C2 nerve root manipulation or sacrifice, reduces bleeding associated with the venous plexus, and leaves the third segment of the vertebral artery unexplored. Pre-operative review of imaging is critical in the placement of C1-C2 instrumentation.
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Affiliation(s)
- Richard P Menger
- Department of Neurosurgery, Louisiana State University of Health Sciences, Shreveport LA
| | - Christopher M Storey
- Department of Neurosurgery, Louisiana State University of Health Sciences, Shreveport LA
| | - Menarvia K C Nixon
- Department of Neurosurgery, Louisiana State University of Health Sciences, Shreveport LA
| | - Justin Haydel
- Department of Neurosurgery, Louisiana State University of Health Sciences, Shreveport LA
| | - Anil Nanda
- Department of Neurosurgery, Louisiana State University of Health Sciences, Shreveport LA
| | - Anthony Sin
- Department of Neurosurgery, Louisiana State University of Health Sciences, Shreveport LA
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Huang DG, Hao DJ, He BR, Wu QN, Liu TJ, Wang XD, Guo H, Fang XY. Posterior atlantoaxial fixation: a review of all techniques. Spine J 2015; 15:2271-81. [PMID: 26165477 DOI: 10.1016/j.spinee.2015.07.008] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 04/24/2015] [Accepted: 07/01/2015] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Posterior atlantoaxial fixation is an effective treatment for atlantoaxial instability. Great advancements on posterior atlantoaxial fixation techniques have been made in the past decades. However, there is no article reviewing all the posterior atlantoaxial fixation techniques yet. PURPOSE The aim was to review the evolution and advancements of posterior atlantoaxial fixation. STUDY DESIGN This was a literature review. METHODS The application of all posterior fixation techniques in atlantoaxial stabilization, including wiring techniques, interlaminar clamp fixation, transarticular fixation, screw-plate systems, screw-rod systems, and hook-screw systems, are reviewed and discussed. Recent advancements on the novel technique of atlantoaxial fixation are described. The combination of the C1 and C2 screws in screw-rod systems are described in detail. RESULTS All fixation techniques are useful. The screw-rod system appears to be the most popular approach. However, many novel or modified fixation methods have been introduced in recent years. CONCLUSIONS Great advancements on posterior atlantoaxial fixation techniques have been made in the past decades. The wiring technique and interlaminar clamps technique have fallen out of favor because of the development of newer and superior fixation techniques. The C1-C2 transarticular screw technique may remain the gold standard for atlantoaxial fusion, whereas screw-rod systems, especially the C1 pedicle screw combined with C2 pedicle/pars screw fixation, have become the most popular fixation techniques. Hook-screw systems are alternatives for atlantoaxial fixation.
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Affiliation(s)
- Da-Geng Huang
- Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, No. 76 Nanguo Rd, Xi'an, Shaanxi, 710054, China
| | - Ding-Jun Hao
- Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, No. 76 Nanguo Rd, Xi'an, Shaanxi, 710054, China.
| | - Bao-Rong He
- Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, No. 76 Nanguo Rd, Xi'an, Shaanxi, 710054, China
| | - Qi-Ning Wu
- Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, No. 76 Nanguo Rd, Xi'an, Shaanxi, 710054, China
| | - Tuan-Jiang Liu
- Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, No. 76 Nanguo Rd, Xi'an, Shaanxi, 710054, China
| | - Xiao-Dong Wang
- Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, No. 76 Nanguo Rd, Xi'an, Shaanxi, 710054, China
| | - Hua Guo
- Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, No. 76 Nanguo Rd, Xi'an, Shaanxi, 710054, China
| | - Xiang-Yi Fang
- Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, No. 76 Nanguo Rd, Xi'an, Shaanxi, 710054, China
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Du JY, Aichmair A, Kueper J, Wright T, Lebl DR. Biomechanical analysis of screw constructs for atlantoaxial fixation in cadavers: a systematic review and meta-analysis. J Neurosurg Spine 2015; 22:151-61. [DOI: 10.3171/2014.10.spine13805] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT
The unique and complex biomechanics of the atlantoaxial junction make the treatment of C1–2 instability a challenge. Several screw-based constructs have been developed for atlantoaxial fixation. The biomechanical properties of these constructs have been assessed in numerous cadaver studies. The purpose of this study was to systematically review the literature on the biomechanical stability achieved using various C1–2 screw constructs and to perform a meta-analysis of the available data.
METHODS
A systematic search of PubMed through July 1, 2013, was conducted using the following key words and Boolean operators: “atlanto [all fields]” AND “axial [all fields]” OR “C1–C2” AND “biomechanic.” Cadaveric studies on atlantoaxial fixation using screw constructs were included. Data were collected on instability models, fixation techniques, and range of motion (ROM). Forest plots were constructed to summarize the data and compare the biomechanical stability achieved.
RESULTS
Fifteen articles met the inclusion criteria. An average (± SD) of 7.4 ± 1.8 cadaveric specimens were used in each study (range 5–12). The most common injury models were odontoidectomy (53.3%) and cervical ligament transection (26.7%). The most common spinal motion segments potted for motion analysis were occiput–C4 (46.7%) and occiput–C3 (33.3%). Four screw constructs (C1 lateral mass–C2 pedicle screw [C1LM–C2PS], C1–2 transarticular screw [C1–C2TA], C1 lateral mass–C2 translaminar screw [C1LM-C2TL], and C1 lateral mass–C2 pars screw [C1LM–C2 pars]) were assessed for biomechanical stability in axial rotation, flexion/extension, and lateral bending, for a total of 12 analyses. The C1LM–C2TL construct did not achieve significant lateral bending stabilization (p = 0.70). All the other analyses showed significant stabilization (p < 0.001 for each analysis). Significant heterogeneity was found among the reported stabilities achieved in the analyses (p < 0.001; I2 > 80% for all significant analyses). The C1LM–C2 pars construct achieved significantly less axial rotation stability (average ROM 36.27° [95% CI 34.22°–38.33°]) than the 3 other constructs (p < 0.001; C1LM–C2PS average ROM 49.26° [95% CI 47.66°–50.87°], C1–C2TA average ROM 47.63° [95% CI 45.22°–50.04°], and C1LM–C2TL average ROM 53.26° [95% CI 49.91°–56.61°]) and significantly more flexion/extension stability (average ROM 13.45° [95% CI 10.53°–16.37°]) than the 3 other constructs (p < 0.001; C1LM–C2PS average ROM 9.02° [95% CI 8.25°–9.80°], C1–C2TA average ROM 7.39° [95% CI 5.60°–9.17°], and C1LM–C2TL average ROM 7.81° [95% CI 6.93°–8.69°]). The C1–C2TA (average ROM 5.49° [95% CI 3.89°–7.09°]) and C1LM–C2 pars (average ROM 4.21° [95% CI 2.19°–6.24°]) constructs achieved significantly more lateral bending stability than the other constructs (p < 0.001; C1LM–C2PS average ROM 1.51° [95% CI 1.23°–1.78°]; C1LM–C2TL average ROM −0.07° [95% CI −0.44° to 0.29°]).
CONCLUSIONS
Meta-analysis of the existing literature showed that all constructs provided significant stabilization in all axes of rotation, except for the C1LM–C2TL construct in lateral bending. There were significant differences in stabilization achieved in each axis of motion by the various screw constructs. These results underline the various strengths and weaknesses in biomechanical stabilization of different screw constructs. There was significant heterogeneity in the data reported across the studies. Standardized spinal motion segment configuration and injury models may provide more consistent and reliable results.
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Costa F, Ortolina A, Attuati L, Cardia A, Tomei M, Riva M, Balzarini L, Fornari M. Management of C1–2 traumatic fractures using an intraoperative 3D imaging–based navigation system. J Neurosurg Spine 2015; 22:128-33. [DOI: 10.3171/2014.10.spine14122] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT
Fractures of C-1 and C-2 are complex and surgical management may be difficult and challenging due to the anatomical relationship sbetween the vertebrae and neurovascular structures. The aim of this study was to evaluate the role, reliability, and accuracy of cervical fixation using the O-arm intraoperative 3D image–based navigation system.
METHODS
The authors evaluated patients who underwent a navigation system–based surgery for stabilization of a fracture of C-1 and/or C-2 from August 2011 to August 2013. All of the fixation screws were intraoperatively checked and their position was graded.
RESULTS
The patient population comprised 17 patients whose median age was 47.6 years. The surgical procedures were as follows: anterior dens screw fixation in 2 cases, transarticular fixation of C-1 and C-2 in 1 case, fixation using the Harms technique in 12 cases, and occipitocervical fixation in 2 cases. A total of 67 screws were placed. The control intraoperative CT scan revealed 62 screws (92.6%) correctly placed, 4 (5.9%) with a minor cortical violation (< 2 mm), and only 1 screw (1.5%) that was judged to be incorrectly placed and that was immediately corrected. No vascular injury of the vertebral artery was observed either during exposition or during screw placement. No implant failure was observed.
CONCLUSIONS
The use of a navigation system based on an intraoperative CT allows a real-time visualization of the vertebrae, reducing the risks of screw misplacement and consequent complications.
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Affiliation(s)
| | | | | | | | | | | | - Luca Balzarini
- 2Radiology, Humanitas Clinical and Research Center, Rozzano, Milan, Italy
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Oh CH, Ji GY, Seo HS, Yoon SH, Hyun D, Park HC. Repeated complication following atlantoaxial fusion: a case report. KOREAN JOURNAL OF SPINE 2014; 11:7-11. [PMID: 24891865 PMCID: PMC4040632 DOI: 10.14245/kjs.2014.11.1.7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 03/14/2014] [Accepted: 03/17/2014] [Indexed: 11/19/2022]
Abstract
A patients with atlantoaixial instability and osodontoideum underwent atlantoaixial fusion (Harms and Melcher technique) with demineralized bone matrix. But, unfortunately, the both pedicle screws in C2 were fractured within 9 weeks follow-up periods after several suspected episode of neck hyper-flexion. Fractured screws were not contact to occipital bone in several imaging studies, but it could irritate the occipital bone when neck extension because the relatively close distance between the occipital bone and C1 posterior arch. The patient underwent revision operation with translaminar screw fixation with autologus iliac bone graft. Postsurgical course were uneventful except donor site pain, but the bony fusion was not satisfied after 4 months follow-up. The patient re-underwent revision operation in other hospital. Continuous complication after atlantoaixial fusion is rare, but the clinical course could be unlucky to patients. Postoperative immobilization could be important to prevent the unintended clinical course of patients.
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Affiliation(s)
- Chang Hyun Oh
- Department of Neurosurgery, Guro TeunTeun Hospital, Seoul, Korea
| | - Gyu Yeul Ji
- Department of Neurosurgery, Guro TeunTeun Hospital, Seoul, Korea
| | - Hyun Sung Seo
- Department of Neurosurgery, Inha University School of Medicine, Incheon, Korea
| | - Seung Hwan Yoon
- Department of Neurosurgery, Inha University School of Medicine, Incheon, Korea
| | - Dongkeun Hyun
- Department of Neurosurgery, Inha University School of Medicine, Incheon, Korea
| | - Hyeong-Chun Park
- Department of Neurosurgery, Inha University School of Medicine, Incheon, Korea
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Fensky F, Kueny RA, Sellenschloh K, Püschel K, Morlock MM, Rueger JM, Lehmann W, Huber G, Hansen-Algenstaedt N. Biomechanical advantage of C1 pedicle screws over C1 lateral mass screws: a cadaveric study. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2014; 23:724-31. [PMID: 24378628 PMCID: PMC3960438 DOI: 10.1007/s00586-013-3143-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 12/14/2013] [Accepted: 12/15/2013] [Indexed: 11/25/2022]
Abstract
PURPOSE The established technique for posterior C1 screw placement is via the lateral mass. Use of C1 monocortical pedicle screws is an emerging technique which utilizes the bone of the posterior arch while avoiding the paravertebral venous plexus and the C2 nerve root. This study compared the relative biomechanical fixation strengths of C1 pedicle screws with C1 lateral mass screws. METHODS Nine human C1 vertebrae were instrumented with one lateral mass screw and one pedicle screw. The specimens were subjected to sinusoidal, cyclic (0.5 Hz) fatigue loading. Peak compressive and tensile forces started from ±25 N and constantly increased by 0.05 N every cycle. Testing was stopped at 5 mm displacement. Cycles to failure, displacement, and initial and end stiffness were measured. Finally, CT scans were taken and the removal torque measured. RESULTS The pedicle screw technique consistently and significantly outperformed the lateral mass technique in cycles to failure (1,083 ± 166 vs. 689 ± 240 cycles), initial stiffness (24.6 ± 3.9 vs. 19.9 ± 3.2 N/mm), end stiffness (16.6 ± 2.7 vs. 11.6 ± 3.6 N/mm) and removal torque (0.70 ± 0.78 vs. 0.13 ± 0.09 N m). Only 33 % of pedicle screws were loose after testing compared to 100 % of lateral mass screws. CONCLUSIONS C1 pedicle screws were able to withstand higher toggle forces than lateral mass screws while maintaining a higher stiffness throughout and after testing. From a biomechanical point of view, the clinical use of pedicle screws in C1 is a promising alternative to lateral mass screws.
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Affiliation(s)
- Florian Fensky
- Department of Trauma, Hand and Reconstructive Surgery, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany,
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Atlantoaxial Fusion: Transarticular Screws versus Screw-Rod Constructs. World Neurosurg 2013; 80:516-7. [DOI: 10.1016/j.wneu.2012.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 11/09/2012] [Indexed: 12/13/2022]
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Takeuchi M, Wakao N, Kamiya M, Niwa A, Osuka K, Takayasu M. Upper cervical cord compression due to a C-1 posterior arch in a patient with ossification of the posterior longitudinal ligament and a kyphotic cervical spine in the protruded-head position. J Neurosurg Spine 2013; 19:431-5. [DOI: 10.3171/2013.7.spine13229] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In this paper the authors report the case of a patient with ossification of the posterior longitudinal ligament (OPLL) below the axial vertebra (C-2) at the kyphotic cervical spine, with an atlas vertebra (C-1) posterior arch that compressed the spinal cord with the head in a pathognomonic position, similar to a protruded position. This condition appears to be very rare. The morphological findings between the kyphotic cervical spine and OPLL, the upper occipitocervical junction, and the protruded-head position are discussed. A 40-year-old man presented with severe pain radiating to both legs when he yawned, sneezed, or extended his jaw (a protruded-head position). A kyphotic cervical spine with OPLL below C-2 was observed using CT and radiography, yet sagittal T2-weighted MRI failed to identify abnormal findings in a neutral or extension position, except for a slight cervical canal stenosis. However, in a pathognomonic protruded-head position, sagittal T2-weighted MRI showed a C-1 posterior arch that severely compressed the spinal cord at the upper cervical level. Therefore, the authors believe that the severe pain radiating to both legs was caused by a spinal canal stenosis due to a C-1 posterior arch impingement. The C-1 posterior arch was resected, and after the surgery, the patient indicated that the intolerable pain had disappeared. In conclusion, in patients with OPLL and a kyphotic cervical spine, the authors propose that the pathognomonic protruded position is valuable for estimating disrupted compensatory mechanisms at the upper cervical junction.
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Affiliation(s)
| | - Norimitsu Wakao
- 2Orthopedic Surgery, Aichi Medical University Hospital, Nagakute, Aichi, Japan
| | - Mitsuhiro Kamiya
- 2Orthopedic Surgery, Aichi Medical University Hospital, Nagakute, Aichi, Japan
| | - Aichi Niwa
- 1Departments of Neurological Surgery and
| | - Koji Osuka
- 1Departments of Neurological Surgery and
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Abstract
STUDY DESIGN Case report. OBJECTIVE To present a previously unreported complication of subarachnoid hemorrhage and hydrocephalus after C1 lateral mass screw insertion. To inform spine specialists of this potential postoperative complication. SUMMARY OF BACKGROUND DATA Damage to the carotid artery, vertebral artery, hypoglossal nerve and dural tears are all recognized complications. Acute hydrocephalus as a result of subarachnoid hemorrhage is not previously reported. METHODS A 63-year-old female with a traumatic C1 ring and C2 peg fracture underwent C1-C2 fixation. During insertion of the C1 lateral mass screws there was significant hemorrhage from the C1-C2 venous plexus. Three days postoperatively, she developed headache, confusion, and became drowsy. RESULTS Computed tomographic scan of the brain revealed hydrocephalus and intraventricular blood that was managed with an external ventricular drain. CONCLUSION The case of acute hydrocephalus due to intraventricular hemorrhage from C1 lateral mass screw placement has not previously been reported. Surgeons performing the procedure should consider the diagnosis if patients display signs of raised intracranial pressure postoperatively. LEVEL OF EVIDENCE N/A.
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Biomechanical evaluation of the Total Atlanto-odontoid Joint Arthroplasty System: an in vitro human cadaveric study. Clin Biomech (Bristol, Avon) 2013; 28:357-63. [PMID: 23510840 DOI: 10.1016/j.clinbiomech.2013.02.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 02/20/2013] [Accepted: 02/21/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND Atlanto-odontoid joint arthroplasty is a motion restoring procedure suggested as an alternative to rigid fixation after surgical decompression. The purpose of this study was to evaluate the kinematics and pullout strength of a novel Total Atlanto-odontoid Joint Arthroplasty System using human cadaveric specimens. METHODS Nondestructive biomechanical tests were performed on 24 fresh craniocervical specimens separated into two groups: 1) the prosthesis implantation group and 2) Harms transoral atlantoaxial plate fixation group. The following configurations were investigated: intact, after decompression, and instrumented. Range of motion and neutral zone were calculated for the C1-C2 segment. In a second experimental series, 8 sets of fresh atlantoaxial specimens were used to test the pullout strength of the atlas-axis components. FINDINGS Compared with Harms rigid fixation, the Total Atlanto-odontoid Joint Arthroplasty System significantly increased the range of motion and neutral zone in all directions (P<.001). In addition, compared with the intact state, the only significant change in the range of motion and neutral zone with the Total Atlanto-odontoid Joint Arthroplasty System implantation was an increase in lateral bending (P<.001). The pullout strength created by the anterior C2 transpedicular screw was greater than that of the C2 vertebral screw and C1 lateral mass screw (P<.001), and the C1 lateral mass screw was stiffer than the C2 vertebral screw (P=.02). INTERPRETATION Biomechanical analyses suggest that the Total Atlanto-odontoid Joint Arthroplasty System was able to provide reliable fixation strength and preserve the normal kinematics of the C1-C2 segment after decompressive procedures.
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Reis MT, Nottmeier EW, Reyes PM, Baek S, Crawford NR. Biomechanical analysis of a novel hook-screw technique for C1–2 stabilization. J Neurosurg Spine 2012; 17:220-6. [DOI: 10.3171/2012.5.spine1242] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The Food and Drug Administration has not cleared the following medical devices for the use described in this study. The following medical devices are being discussed for an off-label use: cervical lateral mass screws.
Object
As an alternative for cases in which the anatomy and spatial relationship between C-2 and a vertebral artery precludes insertion of C-2 pedicle/pars or C1–2 transarticular screws, a technique that includes opposing laminar hooks (claw) at C-2 combined with C-1 lateral mass screws may be used. The biomechanical stability of this alternate technique was compared with that of a standard screw-rod technique in vitro.
Methods
Flexibility tests were performed in 7 specimens (occiput to C-3) in the following 6 different conditions: 1) intact; 2) after creating instability and attaching a posterior cable/graft at C1–2; 3) after removing the graft and attaching a construct comprising C-1 lateral mass screws and C-2 laminar claws; 4) after reattaching the posterior cable-graft at C1–2 (posterior hardware still in place); 5) after removing the posterior cable-graft and laminar hooks and placing C-2 pedicle screws interconnected to C-1 lateral mass screws via rod; and 6) after reattaching the posterior cable-graft at C1–2 (screw-rod construct still in place).
Results
All types of stabilization significantly reduced the range of motion, lax zone, and stiff zone compared with the intact condition. There was no significant biomechanical difference in terms of range of motion or lax zone between the screw-rod construct and the screw-claw-rod construct in any direction of loading.
Conclusions
The screw-claw-rod technique restricts motion much like the standard Harms technique, making it an acceptable alternative technique when aberrant arterial anatomy precludes the placement of C-2 pars/pedicle screws or C1–2 transarticular screws.
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Affiliation(s)
- Marco Túlio Reis
- 1Spinal Biomechanics Laboratory, Department of Neurosurgery Research, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | | | - Phillip M. Reyes
- 1Spinal Biomechanics Laboratory, Department of Neurosurgery Research, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | - Seungwon Baek
- 1Spinal Biomechanics Laboratory, Department of Neurosurgery Research, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | - Neil R. Crawford
- 1Spinal Biomechanics Laboratory, Department of Neurosurgery Research, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
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Feng G, Wendlandt R, Spuck S, Schulz AP. One-screw fixation provides similar stability to that of two-screw fixation for type II dens fractures. Clin Orthop Relat Res 2012; 470:2021-8. [PMID: 22585352 PMCID: PMC3369094 DOI: 10.1007/s11999-012-2389-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 05/01/2012] [Indexed: 01/31/2023]
Abstract
BACKGROUND Anterior screw fixation has been widely adopted for the treatment of type II dens fractures. However, there is still controversy regarding whether one- or two-screw fixation is more appropriate. QUESTIONS/PURPOSES We addressed three questions: (1) Do one- and two-screw fixation techniques differ regarding shear stiffness and rotational stiffness? (2) Can shear stiffness and rotational stiffness after screw fixation be restored to normal? (3) Does stiffness after screw fixation correlate with bone mineral density (BMD)? METHODS We randomly assigned 14 fresh axes into two groups (seven axes each): one receiving one-screw fixation and another receiving two-screw fixation. Shear and torsional stiffness were measured using a nondestructive low-load test in six directions. A transverse osteotomy then was created at the base of the dens and fixed using one or two screws. Shear and torsional stiffness were tested again under the same testing conditions. RESULTS Mean stiffness in all directions after screw fixation was similar in both groups. The stiffness after one- and two-screw fixation was not restored to normal: the mean shear stiffness restored ratio was less than 50% and the mean torsional stiffness restored ratio was less than 6% in both groups. BMD did not correlate with mean stiffness after screw fixation in both groups. CONCLUSIONS One- and two-screw fixation for type II dens fractures provide similar stability but neither restores normal shear or torsional stiffness. CLINICAL RELEVANCE One-screw fixation might be used as an alternative to two-screw fixation. Assumed BMD should not influence surgical decision making.
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Affiliation(s)
- Gang Feng
- Department of Orthopaedic Surgery, 2nd Affiliated Hospital of Zhejiang University College of Medicine, Hangzhou, Zhejiang Province China
| | - Robert Wendlandt
- Laboratory for Biomechanics, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Sebastian Spuck
- Department of Neurosurgery, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Arndt P. Schulz
- Department of Trauma and Orthopaedic Surgery, University Hospital of Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
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Posterior C1-2 fusion with C1 lateral mass and C2 isthmic screws: accuracy of screw position, alignment and patient outcome. Acta Neurochir (Wien) 2012; 154:305-12. [PMID: 22200812 DOI: 10.1007/s00701-011-1224-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 11/01/2011] [Indexed: 10/14/2022]
Abstract
BACKGROUND Transarticular screw fixation is seen as the "gold standard" in instrumented fusion of C1 and C2. However, drawbacks are the necessity of a reduction before instrumentation and a risk of vertebral artery injury. Therefore, C1 lateral mass and C2 isthmic screws are an alternative. The present study assessed the feasibility of C1-2 stabilization with C1 lateral mass and C2 isthmic screws and evaluated quality of life. METHOD All data of 35 consecutive patients treated from May 2006 to September 2009 were collected. Patients had C1 lateral mass and C2 isthmic screws. RESULTS Twenty patients were operated on for traumatic instabilities, six for neoplastic instabilities, five for infectious instabilities and two each for degenerative and congenital instabilities. Sixty-six of 70 C1 screws had an ideal position, while four were placed suboptimal without the need for revision. Twelve of 68 C2 screws were not ideal but acceptable; one screw needed a surgical revision. There was one non-surgery related case of neurological deterioration after multilevel instrumentation. No vascular injuries occurred. Realignment was correct in all patients. After a median follow-up of 12 months, patients showed a reduction of pain, disability and improvements in EQ-5D items. SF36 data compared with a normative population and a historical cohort showed lower levels of function in all domains. CONCLUSION C1-C2 instrumented fusion with lateral mass and isthmic screws is a safe procedure. Sufficient screw position and alignment was possible in all cases. Therefore, at our institution transarticular screws were abandoned in favor of C1 lateral mass and C2 isthmic screws.
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Shetty A, Kini A, Gupta A, Kumar A, Upadhyaya S. Management of traumatic atlanto-axial instability: A retrospective study of eight cases. Indian J Orthop 2012; 46:86-91. [PMID: 22345813 PMCID: PMC3270612 DOI: 10.4103/0019-5413.91641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND C1 lateral mass-C2 transpedicular fixation is an accepted surgical procedure of choice in a large number of cases with traumatic atlanto-axial instability. However, bony and vascular anomalies can predispose to unacceptably high risk with this procedure, And hence are the contraindications for this procedure. The purpose of this study is to analyze the clinical and radiological results in such cases for which only unilateral fixation has been performed in cases where bilateral fixation could not be performed due to various reasons. MATERIALS AND METHODS Eight patients (7 males, 1 female) with a mean age of 41.12 years (range 12-68 years), who presented with traumatic atlanto-axial instability and in whom bilateral fixation could not be performed, were treated with unilateral C1 lateral mass-C2 transpedicular fixation. Of these cases, preoperative vertebral artery occlusion was noted in one case, iatrogenic vertebral artery injury in two cases and bony anomalies or fractures in the remaining of five cases. All patients were evaluated clinically with the American Spinal Injury Association (ASIA) scale and radiologically with computed tomography scans and serial X-ray using criteria to evaluate stability. RESULTS All cases were evaluated at 6 months followup with mean followup of 2 years and one month (range 6 months to 4 years). All eight patients showed adequate stability and fusion at 6 months; clinically there was no significant restriction of neck movement in any of the patient. There was no neurological deterioration in any of the patient at their last follow-up. CONCLUSION Unilateral C1 lateral mass-C2 transpedicular fixation could be considered a viable option in cases of traumatic atlanto-axial instability where vascular and osseous anomalies contradict a bilateral fixation.
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Affiliation(s)
- Arjun Shetty
- Department of Neurosurgery, Kasturba Medical College, Manipal, and Consultant Neurosurgeon, Tejasvini Hospital and SSIOT, Kadri, Mangalore, India
| | - Abhishek Kini
- Department of Orthopaedics and Traumatology, Tejasvini Hospital and SSIOT, Kadri, Mangalore, India,Address for correspondence: Dr. Abhishek R. Kini, Department of Orthopaedics and Traumatology, Tejasvini Hospital and SSIOT, Kadri, Mangalore – 575 002, India. E-mail:
| | - A Gupta
- Department of Neurosurgery, Kasturba Medical College, Manipal, India
| | - Anil Kumar
- Department of Neurosurgery, Kasturba Medical College, Manipal, India
| | - S Upadhyaya
- Department of Neurosurgery, Kasturba Medical College, Manipal, India
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Hong JT, Takigawa T, Udayakunmar R, Shin HK, Simon P, Espinoza Orías AA, Inoue N, An HS. Biomechanical effect of the C2 laminar decortication on the stability of C2 intralaminar screw construct and biomechanical comparison of C2 intralaminar screw and C2 pars screw. Neurosurgery 2011; 69:ons1-6; discussion ons6-7. [PMID: 21415794 DOI: 10.1227/neu.0b013e3182155657] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND There have been no reports of biomechanical stability of C1-2 constructs after decortication of the C2 lamina. In addition, few studies have compared the stability of C2 laminar screw and pars screw constructs. OBJECTIVE To compare the biomechanical stability of 3 different C1-2 construct conditions (C2 pars screw, C2 intralaminar screw, C2 intralaminar construct with C2 laminar decortication). METHODS Fourteen fresh-frozen cadaveric cervical specimens (C1-3) were used. In 7 specimens, pure moments of 1.5 Nm were applied in flexion/extension, lateral bending, and axial rotation. Each specimen was tested in the normal state, in the destabilized state (after odontoidectomy and resection of transverse atlantal ligament), and after application of constructs. After kinematic study, these 7 specimens underwent axial pullout strength testing of pars screw and 50% decorticated C2 intralaminar screws. In another 7 specimens, insertion torque and pullout strength were measured to compare the pars screw and intact C2 intralaminar screw. RESULTS : There were no statistically significant differences between the intact C2 intralaminar and 50% decorticated C2 intralaminar screw constructs in terms of range-of-motion limitations. The C2 pars screw construct was significantly superior to the C2 laminar screw construct in lateral bending (P < .01) and axial rotation (P < .01) and equivalent to the C2 laminar screw construct in flexion/extension (P = .42). There was no significant pullout strength difference between the 3 kinds of C2 screw. CONCLUSION The C1 lateral mass-C2 pars screws construct was stronger than the C1 lateral mass-C2 intralaminar screw construct. Decortication of C2 laminar (up to 50%) did not affect the immediate stability of the C1-2 construct.
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Affiliation(s)
- Jae Taek Hong
- Department of Neurosurgery, Catholic University of Korea, St Vincent's Hospital, Suwon, South Korea
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Complications and outcomes of posterior fusion in children with atlantoaxial instability. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2011; 21:1346-52. [PMID: 22113532 DOI: 10.1007/s00586-011-2083-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 09/12/2011] [Accepted: 11/12/2011] [Indexed: 01/24/2023]
Abstract
INTRODUCTION Atlantoaxial instability (AAI) is an uncommon disease in children. Surgical treatment of pediatric patients with AAI poses a challenge to spine surgeons because of the patients' immature bone quality, extensive anatomical variability, and smaller osseous structures. In this study, the authors report complications and outcomes after posterior fusion in children with AAI. METHODS The authors reviewed medical records of patients 13 years old and younger with AAI who underwent posterior fusion in the Nagoya Spine Group hospitals, a multicenter cooperative study group, from January 1995 to December 2007. We identified 11 patients who underwent posterior fusion, and analyzed their clinical outcomes and complications. To determine if vertical growth within the construct continued after posterior fusion, in three patients at 5 or more years following occipito-cervical (O-C) fusion, intervertebral disc heights and vertebral heights between the fused and non-fused levels were compared on the final follow-up. RESULTS The initial surgeries were C1-C2 fusions in six patients and O-C fusion in five patients. Successful fusion ultimately occurred in all patients, however, the complication rate related to the operations was high (64%). Complications included neurologic deterioration, pedicle fracture with pedicle screw insertion, C1 posterior arch fracture with lateral mass screw insertion, perforation of the skull with a head pin placement, and fusion extension to adjacent vertebrae. Two patients required reoperation. The mean fixed and non-fixed intervertebral disc heights on the final follow-up were 2.6 and 5.3 mm, respectively, showing that the disc height of the fixed level was less than the non-fused level. Each vertebra lengthened similarly between fused and non-fused levels except for C2 which had a lower growth rate than the other vertebrae. CONCLUSIONS A high complication rate should be anticipated after posterior fusion in children with AAI. Careful consideration should be paid to pediatric patients with AAI treated by screw and/or rod systems. After posterior fusion in pediatric patients, each vertebra continued to grow, in contrast the disc height decreased between fused levels.
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A comparison of the Gallie technique and casting versus the harms technique for the treatment of odontoid fractures. J Orthop Trauma 2011; 25:670-3. [PMID: 21885999 DOI: 10.1097/bot.0b013e318214b59e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The objective of this study was to compare perioperative, clinical parameters, complications, and reoperation rate of the Gallie technique and head-neck-chest plaster with the Harms technique in the treatment of odontoid fractures. DESIGN A retrospective study. SETTING Level I spine center. PATIENTS Fifty-seven patients with odontoid fractures treated either with the Gallie technique and casting or the Harms technique between July 2002 and June 2008. INTERVENTION Surgery. MAIN OUTCOME MEASUREMENTS At a minimum of 2-year follow-up, comparison of the two groups was conducted in terms of hospital stay, blood loss, operation time, cost of the first admission, total cost, time to fusion, time to return to previous occupation, Japanese Orthopedic Association scores, visual analog scale scores of neck pain, complications (nonunion, delayed union, hardware breakage, wound infection), and reoperation rate. RESULTS There were no significant differences in terms of hospital stay, time to fusion, Japanese Orthopedic Association scores, neck pain visual analog scale scores, complications, or reoperation rate between the two groups. Blood loss, operation time, cost of the first admission, and total cost were significantly lower in the Gallie group than that in the Harms group. However, the Gallie group took longer to return to previous occupation than the Harms group (P < 0.001). CONCLUSIONS Management of odontoid fractures by either the Gallie technique and casting or the Harms technique was found to be similar in clinical outcomes. Although the Harms technique was associated with more blood loss, operation time, and cost, the Harms technique was found to be superior to the Gallie technique with casting in terms of time to return to previous occupation.
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Lee KH, Kang DH, Lee CH, Hwang SH, Park IS, Jung JM. Inferolateral entry point for c2 pedicle screw fixation in high cervical lesions. J Korean Neurosurg Soc 2011; 50:341-7. [PMID: 22200017 DOI: 10.3340/jkns.2011.50.4.341] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2011] [Revised: 08/12/2011] [Accepted: 10/17/2011] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE The purpose of this retrospective study was to evaluate the efficacy and safety of atlantoaxial stabilization using a new entry point for C2 pedicle screw fixation. METHODS Data were collected from 44 patients undergoing posterior C1 lateral mass screw and C2 screw fixation. The 20 cases were approached by the Harms entry point, 21 by the inferolateral point, and three by pars screw. The new inferolateral entry point of the C2 pedicle was located about 3-5 mm medial to the lateral border of the C2 lateral mass and 5-7 mm superior to the inferior border of the C2-3 facet joint. The screw was inserted at an angle 30° to 45° toward the midline in the transverse plane and 40° to 50° cephalad in the sagittal plane. Patients received followed-up with clinical examinations, radiographs and/or CT scans. RESULTS There were 28 males and 16 females. No neurological deterioration or vertebral artery injuries were observed. Five cases showed malpositioned screws (2.84%), with four of the screws showing cortical breaches of the transverse foramen. There were no clinical consequences for these five patients. One screw in the C1 lateral mass had a medial cortical breach. None of the screws were malpositioned in patients treated using the new entry point. There was a significant relationship between two group (p=0.036). CONCLUSION Posterior C1-2 screw fixation can be performed safely using the new inferolateral entry point for C2 pedicle screw fixation for the treatment of high cervical lesions.
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Affiliation(s)
- Kwang Ho Lee
- Department of Neurosurgery, Gyeongsang National University School of Medicine, Jinju, Korea
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Ni B, Zhou F, Guo Q, Li S, Guo X, Xie N. Modified technique for C1-2 screw-rod fixation and fusion using autogenous bicortical iliac crest graft. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2011; 21:156-64. [PMID: 21823036 DOI: 10.1007/s00586-011-1958-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Revised: 06/01/2011] [Accepted: 07/24/2011] [Indexed: 01/05/2023]
Abstract
INTRODUCTION Various techniques have been described for posterior atlantoaxial fusion. Sublaminar passage of the wire/cable is cumbersome with a risk of spinal cord injury. Packing morselized bone grafts into the C1-2 facet joints may be difficult and it may cause massive bleeding and neuropathic pain or posterior scalp numbness postoperatively. We introduce a modified method by using C1-2 screw-rod fixation (SRF) to compress a structural iliac bone graft between the posterior elements of C1 and C2 without supplemental wiring construct. MATERIALS AND METHODS From December 2006 to May 2009, 35 consecutive patients with atlantoaxial instability treated by this method were reviewed retrospectively. Clinical and radiographic history was recorded. Patients with neck pain had relieved significantly after surgery and the neurologic status was also improved greatly. Thirty-three (94.3%) patients gained bony fusion at 3 months postoperatively. No vertebral artery and spinal cord injuries were noted. There was no instrumentation failure during the observation period. CONCLUSION We conclude that the C1-2 SRF with construct-compression structural bone grafting can be used for C1-2 fusion with relatively simple performance and less time-consuming in selected cases.
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Affiliation(s)
- Bin Ni
- Department of Orthopedics, Changzheng Hospital, The Second Military Medical University, 415 Fengyang Road, Huangpu, Shanghai, 200003, People's Republic of China.
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Agrawal A, Agarwal A, Reyes PM. A novel technique of odontoidoplasty and C1 arch reconstruction: anatomical and biomechanical basis. Neurosurgery 2011; 68:103-113; discussion 113. [PMID: 21206300 DOI: 10.1227/neu.0b013e31820934a9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Transoral odontoidectomy and resection of the anterior C1 arch destabilize the atlantoaxial joint and risk its stability. OBJECTIVE To preserve stability in such cases we devised and evaluated a proof-of-concept study. The arch and dens were dissected and decompression was performed on cadavers. The dens was replaced with an odontoid screw, and the C1 arch was replaced with a rib-graft substitute using miniplates. We assessed the biomechanical strength of the C1 ring and 3D occipitoatlantoaxial flexibility before and after the repair. METHODS Five silicon-injected fixed cadaver heads were dissected. The arch of C1 and dens were preserved and reconstructed using odontoid screws and miniplates. Once the feasibility of the technique was established, we biomechanically tested 6 cadaveric occiput-C2 specimens in 3 phases: (1) intact/normal range of motion (ROM), (2) after transection of dens and C1 arch, and (3) with odontoidoplasty using odontoid screws and C1 arch reconstruction. RESULTS After odontoidectomy and arch removal, angular ROM increased significantly in all directions of loading. Resection increased flexion-extension at the occiput-C1 and at C1-C2 by 21% and 129%, respectively. Reconstruction slightly increased flexion-extension stability (16% and 107%, respectively) relative to normal.With 70 N applied compression, the C1 ring separation was 1145% greater than normal. After reconstruction, the separation was only 89% greater than normal (statistically significant, P = .002). CONCLUSION C1 arch reconstruction with or without odontoidoplasty restores only partial angular stability of the atlantoaxial joint but provides restoration of the ability of the C1 lateral masses to resist splaying, often observed as postodontoidectomy cranial settling.
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Affiliation(s)
- Abhishek Agrawal
- Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona 85013, USA
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Abstract
Instrumentation in the upper cervical spine has changed considerably in the past two decades. Previous stand-alone wiring techniques have been made largely obsolete with the development of occipital segmental plating, transarticular screws, and C1 lateral mass screws, as well as a myriad of C2 fixation options, including pedicle, pars, and translaminar screws. Polyaxial screws and segmental fixation are more user-friendly than stand-alone wiring and provide a stronger construct. Awareness of the risks and benefits associated with the use of modern instrumentation and thorough familiarity with the anatomy of the upper cervical spine are essential to avoid complications and optimize outcomes.
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Kakarla UK, Valdivia JV, Sonntag VKH, Bambakidis NC. Intracranial hemorrhage and spinal cord injury from a fractured C1-C2 sublaminar cable: case report. Neurosurgery 2010; 66:E1203-4. [PMID: 20495390 DOI: 10.1227/01.neu.0000369198.70959.e1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE This is a unique case report of a fractured atlantoaxial interspinous multistranded cable leading to intracranial hemorrhage and spinal cord injury. CLINICAL PRESENTATION A 61-year-old woman, with a history of rheumatoid arthritis and C1-C2 interspinous wiring with allograft for atlantoaxial instability, presented with neck pain and progressive decline in mental status. Prior to transfer to our institution from a referral hospital, imaging studies revealed progressive hydrocephalus with interval development of subarachnoid and fourth ventricular hemorrhage. Initial and repeat angiographic work-up was negative for vascular lesions. Magnetic resonance imaging revealed a subdural hematoma and signal changes at the cervicomedullary junction. Computed tomography of the cervical spine revealed a fractured interspinous cable, intradural penetration, and atlantoaxial instability. INTERVENTION After ventriculostomy, both the patient's mental status and quadriparesis improved to a C on the American Spinal Injury Association (ASIA) scale. During surgery, the fractured cable and subdural hematoma were removed revealing an area of spinal cord impalement. She underwent C1-C3 lateral mass fixation with iliac crest autograft for fusion and was discharged to rehabilitation after a ventriculoperitoneal shunt was placed. At her 6-month follow-up, she was independent and had improved to ASIA E. Computed tomography confirmed fusion. CONCLUSION Spinal instrumentation eventually fails from pseudarthrosis and can cause neurological injury. In patients with atlantoaxial instability, direct C1-C2 screw fixation with posterior interspinous wiring using autograft offers the best chance for fusion. Cervical spine pathology can cause intracranial hemorrhage, and unconventional causes of injury must be considered when routine workup is negative.
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Affiliation(s)
- Udaya K Kakarla
- Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
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Brasiliense LBC, Lazaro BCR, Reyes PM, Fox D, Sonntag VKH, Crawford NR. Stabilization of the atlantoaxial joint with C1-C3 lateral mass screw constructs: biomechanical comparison with standard technique. Neurosurgery 2010; 67:422-8. [PMID: 21099568 DOI: 10.1227/neu.0b013e3181fb414c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Anatomically and biomechanically, the atlantoaxial joint is unique compared with the remainder of the cervical spine. OBJECTIVE To assess the in vitro stability provided by 2 C2 screw sparing techniques in a destabilized model of the atlantoaxial joint and compare with the gold standard system. METHODS The 3-dimensional intervertebral motion of 7 human cadaveric cervical spine specimens was recorded stereophotogrammetrically while applying nonconstraining, nondestructive pure moments during flexion-extension, left and right axial rotation, and left and right lateral bending. Each specimen was tested in the intact state, followed by destabilization (odontoidectomy) and fixation as follows: (1) C1 and C3 lateral mass screws rods with sublaminar wiring of C2 (LC1-C3 + SW), (2) C1 and C3 lateral mass screws rods with a cross-link in the C1-2 interlaminar space (LC1-C3 + CL), (3) C1 and C3 lateral mass screw rods alone (negative control), and (4) C1 lateral mass and C2 pedicle screws rods augmented with C1-2 interspinous wire and graft (LC1-PC2, control group). RESULTS Compared with the intact spine, each instrumented state significantly stabilized range of motion and lax zone at C1-2 (P < .001, 1-way repeated-measures analysis of variance). LC1-C3 + SW was equivalent to LC1-PC2 during flexion and lateral bending and superior to LC1-C3 + CL during lateral bending, while LC1-C3 + CL was equivalent to LC1-PC2 only during flexion. In all other comparisons, LC1-PC2 was superior to both techniques. CONCLUSION From a biomechanical perspective, both C2 screw sparing techniques provided sufficient stability to be regarded as an alternative for C1-2 fixation. However, because normal motion across C2-3 is sacrificed, these constructs should be used in patients with unfavorable anatomy for standard fixations.
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Affiliation(s)
- Leonardo B C Brasiliense
- Spinal Biomechanics Laboratory, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
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Park YS, Kang DH, Park KB, Hwang SH. Posterior atlantoaxial screw-rod fixation in a case of aberrant vertebral artery course combined with bilateral high-riding vertebral artery. J Korean Neurosurg Soc 2010; 48:367-70. [PMID: 21113368 DOI: 10.3340/jkns.2010.48.4.367] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 04/25/2010] [Accepted: 10/04/2010] [Indexed: 11/27/2022] Open
Abstract
We present a case of posterior atlantoaxial screw-rod fixation in a patient with an aberrant vertebral artery (VA) course combined with bilateral high-riding VA. An aberrant VA which courses below the posterior arch of the atlas (C1) that does not pass through the C1 transverse foramen and without an osseous anomaly is rare. However, it is important to consider an abnormal course of the VA both preoperatively and intraoperatively in order to avoid critical vascular injuries in procedures which require exposure or control of the VA, such as the far-lateral approach and spinal operations.
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Affiliation(s)
- Young Seop Park
- Department of Neurosurgery, Gyeongsang National University School of Medicine, Jinju, Korea
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Lee SH, Kim ES, Sung JK, Park YM, Eoh W. Clinical and radiological Comparison of treatment of atlantoaxial instability by posterior C1–C2 transarticular screw fixation or C1 lateral mass-C2 pedicle screw fixation. J Clin Neurosci 2010; 17:886-92. [DOI: 10.1016/j.jocn.2009.10.008] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 10/11/2009] [Accepted: 10/12/2009] [Indexed: 11/24/2022]
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Biomechanical evaluation of an atlantoaxial lateral mass fusion cage with C1-C2 pedicle fixation. Spine (Phila Pa 1976) 2010; 35:E624-32. [PMID: 20505567 DOI: 10.1097/brs.0b013e3181cf412b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A biomechanical testing protocol was used to evaluate atlantoaxial fixation techniques in a human cadaveric model. OBJECTIVE To compare in vitro biomechanics of atlantoaxial lateral mass fusion cage combined with C1-C2 pedicle screw technique with those of C1-C2 pedicle screw technique alone and C1-C2 transarticular screws combined with Gallie wires. SUMMARY OF BACKGROUND DATA An atlantoaxial lateral mass fusion cage was designed, knowing that the cage, when rigidly combined with C1-C2 pedicle screws, could offer other fusion spots for atlantoaxial stabilization in cases when the posterior arch of the atlas is absent or removed for decompression and a Gallie fixation is impossible. No comparative in vitro biomechanical test has been conducted previously to evaluate the feasibility of this method. METHODS Anatomic measurements of the atlantoaxial lateral masses were taken using computed tomography in normal human subjects. Six fresh-frozen human cadaveric cervical spines (C0-C4) were used in the biomechanical study. Specimens were tested in their intact condition, after destabilization via transverse-alar-apical ligament disruption, and after implantation of 3 fixation constructs: (1) transarticular screws combined with Gallie wires, (2) C1-C2 pedicle screws, and (3) atlantoaxial lateral mass fusion cage combined with C1-C2 pedicle screws. Pure moment loading up to 1.5 Nm in flexion/extension, right-left lateral bending, and right-left axial rotation was applied to the occiput, and relative intervertebral rotations were determined using stereophotogrammetry. Range of motion for the intact, destabilized, and 3 fixation scenarios were determined. RESULTS The anatomic data indicated that feasible cage design were in 3 sizes: 11/8, 12/9, and 13/10 mm for length/width, and 3.5, 4, and 4.5 mm for height. The biomechanical data indicated that transverse-alar-apical ligament disruption significantly increased C1-C2 motion for all directions. All the 3 fixation techniques significantly reduced motion compared with the intact and destabilized cases. There were no statistically significant differences among the 3 fixation techniques. CONCLUSION The biomechanical study indicated that, contrary to expectation, addition of a cage did not increase the stability compared with C1-C2 pedicle screw alone. However, the C1 + C2 + Cage technique may be a viable alternative for atlantoaxial stabilization when the posterior arch of the atlas is absent or removed for decompression and a Gallie fixation is impossible.
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Hoh DJ, Liu CY, Wang MY. A radiographic computed tomography–based study to determine the ideal entry point, trajectory, and length for safe fixation using C-2 pars interarticularis screws. J Neurosurg Spine 2010; 12:602-12. [DOI: 10.3171/2009.12.spine09543] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Object
Effective methods for fixation of the axis include C1–2 transarticular and C-2 pedicle screw placement. Both techniques pose a risk of vertebral artery (VA) injury in patients with narrow pedicles or an enlarged, high-riding VA. Pars screws at C-2 avoid the pedicle, but can cause VA injury with excessively long screws. Therefore, the authors evaluated various entry points and trajectories to determine ideal pars screw lengths that avoid breaching the transverse foramen.
Methods
Both pars were studied on 50 CT scans (100 total). Various pars lengths were assessed using 2 entry points and 3 trajectories (6 measurements). Entry point A was the superior one-fourth of the lateral mass. Entry point B was 3-mm rostral to the inferior aspect of the lateral mass. Using entry points A and B, Trajectory 1 was the minimum distance to the transverse foramen; Trajectory 2 was the maximum distance to the transverse foramen; and Trajectory 3 was the steepest angle to the pars/C-2 superior facet junction without transverse foramen breach.
Results
The mean patient age was 46 ± 17 years, and 84% of the CT scans reviewed were obtained in men. There was no significant difference in right or left measurements. Entry point B demonstrated greater pars lengths for each trajectory compared with entry point A (p < 0.0001). For both entry points, Trajectory 3 provided the greatest pars length. Using Trajectory 3 with entry point B, 84, 95, and 99% had a pars length that measured ≥ 18, 16, and 14 mm, respectively. Using Trajectory 3 with Entry point A, only 41, 64, and 87% had a pars length that measured ≥ 18, 16, and 14 mm, respectively.
Conclusions
Using an entry point 3-mm rostral to the inferior edge of the lateral mass and a trajectory directed toward the superior facet/pars junction, 99% of partes interarticularis in this study would tolerate a 14-mm screw without breach of the transverse foramen.
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Affiliation(s)
- Daniel J. Hoh
- 1Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California; and
| | - Charles Y. Liu
- 1Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California; and
| | - Michael Y. Wang
- 2Department of Neurological Surgery, Miller School of Medicine, University of Miami, Florida
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Thomas JA, Tredway T, Fessler RG, Sandhu FA. An alternate method for placement of C-1 screws. J Neurosurg Spine 2010; 12:337-41. [PMID: 20367368 DOI: 10.3171/2009.10.spine08541] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Several techniques for the surgical stabilization of the atlas and the axis have been described. Placement of C-1 lateral mass screws is one of the latest technical advances, and has gained popularity due to its efficacy and biomechanical advantages. However, the technique for placement of C-1 lateral mass screws, as first described by Harms, can cause excessive bleeding or irritation of the C-2 nerve. An alternative technique is available for the placement of C-1 lateral mass screws that completely avoids the C-2 nerve/ganglion and its associated venous plexus. This new technique mitigates some of the risk associated with the Harms techniques and eliminates the need to use specialized screws (that is, smooth shanks).
Methods
Twenty-six patients underwent atlantoaxial or occipitocervical fusions incorporating the alternative technique of C-1 screw placement. Three surgeons at 3 different institutions performed the surgeries. Standard lateral fluoroscopy and fully threaded polyaxial screws were used in each case.
Results
Forty-nine screws were placed in C-1 lateral masses by using the new technique. Solid arthrodesis was achieved in all cases, with a mean follow-up period of 30 months. There were no cases of CSF leakage, new neurological deficit, injury to the C-2 ganglion, vertebral artery injury, or hardware failures.
Conclusions
The technique is a safe and effective way to fixate C-1 while avoiding the C-2 nerve/ganglion and venous plexus. The results indicate that excellent clinical and radiographic outcomes can be achieved with this new technique.
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Affiliation(s)
- J. Alex Thomas
- 1Departments of Neurosurgery, Georgetown University Hospital, Washington, DC
| | | | | | - Faheem A. Sandhu
- 1Departments of Neurosurgery, Georgetown University Hospital, Washington, DC
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Simsek S, Yigitkanli K, Seckin H, Akyol Ç, Belen D, Bavbek M. Freehand C1 lateral mass screw fixation technique: our experience. ACTA ACUST UNITED AC 2009; 72:676-81. [DOI: 10.1016/j.surneu.2009.06.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Accepted: 06/11/2009] [Indexed: 11/15/2022]
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Haque A, Price AV, Sklar FH, Swift DM, Weprin BE, Sacco DJ. Screw fixation of the upper cervical spine in the pediatric population. Clinical article. J Neurosurg Pediatr 2009; 3:529-33. [PMID: 19485741 DOI: 10.3171/2009.2.peds08149] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECT Rigid fixation of the upper cervical spine has become an established method of durable stabilization for a variety of craniocervical pathological entities in children. In children, specifically, the use of C1-2 transarticular screws has been proposed in recent literature to be the gold standard configuration for pathology involving these levels. The authors reviewed the use of rigid fixation techniques alternative to C1-2 transarticular screws in children. Factors evaluated included ease of placement, complications, and postoperative stability. METHODS Seventeen patients, ranging in age from 3 to 17 years (mean 9.6 years), underwent screw fixation involving the atlas or axis for a multitude of pathologies, including os odontoideum, Down syndrome, congenital instability, iatrogenic instability, or posttraumatic instability. All patients had preoperative instability of the occipitocervical or atlantoaxial spine demonstrated on dynamic lateral cervical spine radiographs. All patients also underwent preoperative CT scanning and MR imaging to evaluate the anatomical feasibility of the selected hardware placement. Thirteen patients underwent C1-2 fusion, and 4 underwent occipitocervical fusion, all incorporating C-1 lateral mass screws, C-2 pars screws, and/or C-2 laminar screws within their constructs. Patients who underwent occipitocervical fusion had no instrumentation placed at C-1. One patient's construct included sublaminar wiring at C-2. All patients received autograft onlay either from from rib (in 15 patients), split-thickness skull (1 patient), or local bone harvested within the operative field (1 patient). Nine patients' constructs were supplemented with recombinant human bone morphogenetic protein at the discretion of the attending physician. Eight patients had surgical sacrifice of 1 or both C-2 nerve roots to better facilitate visualization of the C-1 lateral mass. One patient was placed in halo-vest orthosis postoperatively, while the rest were maintained in rigid collars. RESULTS All 17 patients underwent immediate postoperative CT scanning to evaluate hardware placement. Follow-up was achieved in 16 cases, ranging from 2 to 39 months (mean 14 months), and repeated dynamic lateral cervical spine radiography was performed in these patients at the end of their follow-up period. Some, but not all patients, also underwent delayed postoperative CT scans, which were done at the discretion of the treating attending physician. No neurovascular injuries were encountered, no hardware revisions were required, and no infections were seen. No postoperative pain was seen in patients who underwent C-2 nerve root sacrifice. Stability was achieved in all patients postoperatively. In all patients who underwent delayed postoperative CT scanning, the presence of bridging bone was shown spanning the fused levels. CONCLUSIONS Screw fixation of the atlas using lateral mass screws, in conjunction with C-2 root sacrifice in selected cases, and of the axis using pars or laminar screws is a safe method for achieving rigid fixation of the upper cervical spine in the pediatric population.
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Affiliation(s)
- Atif Haque
- Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
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Hue YH, Chun HJ, Yi HJ, Oh SH, Oh SJ, Ko Y. Unilateral posterior atlantoaxial transarticular screw fixation in patients with atlantoaxial instability : comparison with bilateral method. J Korean Neurosurg Soc 2009; 45:164-8. [PMID: 19352478 DOI: 10.3340/jkns.2009.45.3.164] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 02/22/2009] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE Bilateral C1-2 transarticular screw fixation (TAF) with interspinous wiring has been the best treatment for atlantoaxial instability (AAI). However, several factors may disturb satisfactory placement of bilateral screws. This study evaluates the usefulness of unilateral TAF when bilateral TAF is not available. METHODS Between January 2003 and December 2007, TAF was performed in 54 patients with AAI. Preoperative studies including cervical x-ray, three dimensional computed tomogram, CT angiogram, and magnetic resonance image were checked. The atlanto-dental interval (ADI) was measured in preoperative period, immediate postoperatively, and postoperative 1, 3 and 6 months. RESULTS Unilateral TAF was performed in 27 patients (50%). The causes of unilateral TAF were anomalous course of vertebral artery in 20 patients (74%), severe degenerative arthritis in 3 (11%), fracture of C1 in 2, hemangioblastoma in one, and screw malposition in one. The mean ADI in unilateral group was measured as 2.63 mm in immediate postoperatively, 2.61 mm in 1 month, 2.64 mm in 3 months and 2.61 mm in 6 months postoperatively. The mean ADI of bilateral group was also measured as following; 2.76 mm in immediate postoperative, 2.71 mm in 1 month, 2.73 mm in 3 months, 2.73 mm in 6 months postoperatively. Comparison of ADI measurement showed no significant difference in both groups, and moreover fusion rate was 100% in bilateral and 96.3% in unilateral group (p=0.317). CONCLUSION Even though bilateral TAF is best option for AAI in biomechanical perspectives, unilateral screw fixation also can be a useful alternative in otherwise dangerous or infeasible cases through bilateral screw placement.
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Affiliation(s)
- Yun Hee Hue
- Department of Neurosurgery, Hanyang University Medical Center, Seoul, Korea
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Rocha R, Sawa AGU, Baek S, Safavi-Abbasi S, Hattendorf F, Sonntag VKH, Crawford NR. Atlantoaxial rotatory subluxation with ligamentous disruption: a biomechanical comparison of current fusion methods. Neurosurgery 2009; 64:ons137-43; discussion ons143-4. [PMID: 19240563 DOI: 10.1227/01.neu.0000335778.31497.5b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE We evaluated the biomechanical effects of 4 instrumented configurations after induced atlantoaxial rotatory subluxation: transarticular screw fixation (T/A) and polyaxial C1 lateral mass and C2 pedicle screw and rod fixation (LC1-PC2) for atlantoaxial arthrodesis with unilateral and bilateral instrumentation. METHODS Three-dimensional intervertebral motion was tracked stereophotogrammetrically while 14 human cadaveric spine specimens underwent nonconstraining pure moment loading. Nondestructive loads were applied quasi-statistically in 0.25-Nm increments to a maximum load of 1.5 Nm during flexion-extension, right and left axial rotation, and right and left lateral bending. Hyperrotation injuries were created using torsional loads applied during left axial rotation until visible failure occurred. RESULTS In the normal condition, the values for angular range of motion, lax zone (zone of ligamentous laxity), and stiff zone (zone of ligamentous stretching) were similar in both groups in all directions of loading, with no significant differences (P > 0.05) between groups at C0-C1 or C1-C2. Both instrumentation systems (bilateral configurations) substantially stabilized angular motion at C1-C2 (P < 0.05) during all loading modes for the T/A group, and during all but right lateral bending (P = 0.072) for the LC1-PC2 group. The mean failure load for both intact and instrumented specimens was slightly greater, but not significant for the LC1-PC2 group compared with the T/A group (P > 0.14). CONCLUSION Both methods fixated atlantoaxial subluxation equally well. Compared with unilateral instrumentation, a bilateral configuration with the LC1-PC2 technique significantly increased stability during extension (P < 0.05). During axial rotation, bilateral T/A screws significantly increased stability compared with unilateral fixation (P < 0.02).
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Affiliation(s)
- Rogério Rocha
- Spinal Biomechanics Laboratory, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
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C1 pedicle screws versus C1 lateral mass screws: comparisons of pullout strengths and biomechanical stabilities. Spine (Phila Pa 1976) 2009; 34:371-7. [PMID: 19214096 DOI: 10.1097/brs.0b013e318193a21b] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN In vitro biomechanical study. OBJECTIVE To compare the pullout strengths and the biomechanical stabilities afforded by C1 lateral mass screws and C1 pedicle screws using bicortical and unicortical fixation techniques. SUMMARY OF BACKGROUND DATA Posterior screw fixation techniques in the atlas including C1 lateral mass screw and C1 pedicle screw. The shortcomings of C1 lateral mass screw technique and potential risks of bicortical fixation method were recently described; C1 pedicle screw technique with unicortical fixation might overcome these anatomic and clinical drawbacks. However, it is unknown whether the biomechanical characteristics of unicortical C1 pedicle screw are comparable with that of bicortical C1 lateral mass screw. METHODS.: Bicortical or unicortical C1 pedicle screws and C1 lateral mass screws were inserted into 12 adult fresh human C1 specimens. Pullout strength was evaluated using a material testing machine. The construct's stability of bicortical C1 lateral mass screws or unicortical C1 pedicle screws incorporating unicortical C2 pedicle screws was compared with bilateral transarticular screws using another 6 fresh cervical cadaver spines. Pullout strength and biomechanical stability differences were compared statistically. RESULTS Bicortical C1 pedicle screws provided the biggest pullout strength (1757.0 +/- 318.7 N) of all 4 methods, whereas unicortical C1 lateral mass screws provided the weakest(794.5 +/- 314.8 N). However, there were no statistically significant differences between bicortical C1 lateral mass screws (1243.8 +/- 350.0 N) and unicortical C1 pedicle screws (1192.5 +/- 172.6 N). Furthermore, there was no statistically significant difference of biomechanical construct stability between unicortical C1 pedicle screw-rod constructs and bicortical C1 lateral mass screw-rod constructs. CONCLUSION C1 pedicle screws are stiffer than C1 lateral mass screws. Unicortical C1 pedicle screw provided the same pullout resistance and three-dimensional stability as bicortical C1 lateral mass fixation. Although lateral mass screw placement into C1 requires bicortical purchase, pedicle screw insertion into the atlas only requires unicortical fixation.
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