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Tanaka M, Askar AEKA, Kumawat C, Arataki S, Komatsubara T, Taoka T, Uotani K, Oda Y. A Novel Technique for Basilar Invagination Treatment in a Patient with Klippel-Feil Syndrome: A Clinical Example and Brief Literature Review. MEDICINA (KAUNAS, LITHUANIA) 2024; 60:616. [PMID: 38674263 PMCID: PMC11051808 DOI: 10.3390/medicina60040616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Revised: 03/21/2024] [Accepted: 04/04/2024] [Indexed: 04/28/2024]
Abstract
Objectives and Background: To present a novel technique of treatment for a patient with basilar invagination. Basilar invagination (BI) is a congenital condition that can compress the cervicomedullary junction, leading to neurological deficits. Severe cases require surgical intervention, but there is debate over the choice of approach. The anterior approach allows direct decompression but carries high complication rates, while the posterior approach provides indirect decompression and offers good stability with fewer complications. Materials and Methods: A 15-year-old boy with severe myelopathy presented to our hospital with neck pain, bilateral upper limb muscle weakness, and hand numbness persisting for 4 years. Additionally, he experienced increased numbness and gait disturbance three months before his visit. On examination, he exhibited hyperreflexia in both upper and lower limbs, muscle weakness in the bilateral upper limbs (MMT 4), bilateral hypoesthesia below the elbow and in both legs, mild urinary and bowel incontinence, and a spastic gait. Radiographs revealed severe basilar invagination (BI). Preoperative images showed severe BI and that the spinal cord was severely compressed with odontoid process. Results: The patient underwent posterior surgery with the C-arm free technique. All screws including occipital screws were inserted into the adequate position under navigation guidance. Reduction was achieved with skull rotation and distraction. A follow-up at one year showed the following results: Manual muscle testing results and sensory function tests showed almost full recovery, with bilateral arm recovery (MMT 5) and smooth walking. The cervical Japanese Orthopedic Association score of the patient improved from 9/17 to 16/17. Postoperative images showed excellent spinal cord decompression, and no major or severe complications had occurred. Conclusions: Basilar invagination alongside Klippel-Feil syndrome represents a relatively uncommon condition. Utilizing a posterior approach for treating reducible BI with a C-arm-free technique proved to be a safe method in addressing severe myelopathy. This novel navigation technique yields excellent outcomes for patients with BI.
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Affiliation(s)
- Masato Tanaka
- Department of Orthopaedic Surgery, Okayama Rosai Hospital, Okayama 702-8055, Japan; (A.E.K.A.A.); (C.K.); (S.A.); (T.K.); (T.T.)
| | - Abd El Kader Al Askar
- Department of Orthopaedic Surgery, Okayama Rosai Hospital, Okayama 702-8055, Japan; (A.E.K.A.A.); (C.K.); (S.A.); (T.K.); (T.T.)
| | - Chetan Kumawat
- Department of Orthopaedic Surgery, Okayama Rosai Hospital, Okayama 702-8055, Japan; (A.E.K.A.A.); (C.K.); (S.A.); (T.K.); (T.T.)
| | - Shinya Arataki
- Department of Orthopaedic Surgery, Okayama Rosai Hospital, Okayama 702-8055, Japan; (A.E.K.A.A.); (C.K.); (S.A.); (T.K.); (T.T.)
| | - Tadashi Komatsubara
- Department of Orthopaedic Surgery, Okayama Rosai Hospital, Okayama 702-8055, Japan; (A.E.K.A.A.); (C.K.); (S.A.); (T.K.); (T.T.)
| | - Takuya Taoka
- Department of Orthopaedic Surgery, Okayama Rosai Hospital, Okayama 702-8055, Japan; (A.E.K.A.A.); (C.K.); (S.A.); (T.K.); (T.T.)
| | - Koji Uotani
- Department of Orthopaedic Surgery, Okayama University Hospital, Okayama 700-8558, Japan; (K.U.); (Y.O.)
| | - Yoshiaki Oda
- Department of Orthopaedic Surgery, Okayama University Hospital, Okayama 700-8558, Japan; (K.U.); (Y.O.)
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Ramos-Dávila EM, Meléndez-Flores JD, Álvarez-Pérez R, Barrera-Flores FJ, Martínez-Cobos MC, Pinales-Razo R, Quiroga-Garza A, Zarate-Garza P, Sanchez-Gomez A, Guzman-Lopez S, Elizondo-Omaña RE. Occipital condyle screw fixation viability according to age and gender anatomy: A computed tomography-based analysis. Clin Neurol Neurosurg 2020; 200:106358. [PMID: 33223342 DOI: 10.1016/j.clineuro.2020.106358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To assess the Occipital condyle morphology in an all-age population of Northeastern Mexico, and determine age and gender related changes for surgical viability. METHODS A total of 175 consecutive HRCT scans were included and divided into 5 age groups. The condylar length, width, height, sagittal angle, anterior, posterior and medial intercondylar distances, and intercondylar angle of the OC were measured. RESULTS Mean condylar length, width, and height in total population were 20.58 mm, 9.42 mm, and 9.02 mm, respectively. Differences were observed in most morphometric parameters when comparing age groups. Significant intergender differences in total population were observed in most parameters, when individualizing each age group the height remained significant in all. The group with the least height measurement was aged 5-9 years, this however, could allow the OC screw (≥6.5 mm) placement. CONCLUSION Differences in most morphometric parameters of OC were observed between age groups and gender, particularly patients with 5-9 years. However, all groups presented a minimum height that allows the placement of a standard screw. A preoperative imaging study is always recommended due to the variability and complexity of the region.
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Affiliation(s)
| | | | - Ricardo Álvarez-Pérez
- Universidad Autónoma de Nuevo León, Facultad de Medicina, Hospital Universitario "Dr. José Eleuterio González", Department of Radiology and Imaging, Monterrey, Mexico.
| | | | - Maria C Martínez-Cobos
- Universidad Autónoma de Nuevo León, Facultad de Medicina, Hospital Universitario "Dr. José Eleuterio González", Department of Radiology and Imaging, Monterrey, Mexico.
| | - Ricardo Pinales-Razo
- Universidad Autónoma de Nuevo León, Facultad de Medicina, Hospital Universitario "Dr. José Eleuterio González", Department of Radiology and Imaging, Monterrey, Mexico.
| | | | - Patricio Zarate-Garza
- Human Anatomy Department, Faculty of Medicine, Universidad Autónoma, Monterrey, Mexico.
| | - Arnulfo Sanchez-Gomez
- Human Anatomy Department, Faculty of Medicine, Universidad Autónoma, Monterrey, Mexico.
| | - Santos Guzman-Lopez
- Human Anatomy Department, Faculty of Medicine, Universidad Autónoma, Monterrey, Mexico.
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Lou ZQ, Wang Y, Xu DL, Li GQ, Ma WH, Ruan CY, Zhao HG. Safe trajectory for an occipital condyle screw: A computer simulation study. J Orthop Surg (Hong Kong) 2020; 27:2309499019879540. [PMID: 31645192 DOI: 10.1177/2309499019879540] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE The purpose of this study was to evaluate the feasibility of posterior occipital condyle screw (OCS) placement analysis of the safe trajectory area for screw insertion. METHODS Computed tomographic angiography scans of patients (46 males and 27 females) with normal occipitocervical structures were obtained consecutively. Vertebral artery (VA)-occiput distance <4.0 mm was defined as "unfeasible" for OCS fixation, and occipital-atlas angulation was measured to assess the feasibility of screw placement. Next, the placement of 3.5 mm diameter OCS was simulated, the probability of breach of structures surrounding occipital condyles was calculated, and placement parameters were analyzed. RESULTS OCS placement was feasible in 91.1% (133/146) of occipital condyles, and the feasible probability also presented a significant sex-related difference: The probability was higher for males than for females (95.7% vs. 83.3%, p < 0.05). The incidence of anatomical structures injured under screw placement limitation was 18.8% (VA), 81.2% (hypoglossal canal), 59.4% (occipital-atlas joint), and 40.6% (occiput bone surface). There were no significant differences between the left and right condyles in relation to the measured parameters (p > 0.05). The screw range of motion was significantly smaller in females than in males (p < 0.05). The feasibility of OCS placement and OCS range of motion were significantly greater in the kyphosis group (>5°) than in the other two groups (p < 0.05). CONCLUSION OCS placement is a feasible technique for occipital-cervical fusion. The male group and occipitocervical region kyphosis group had a wider available space for OCS placement. Tangent angulation may be useful for the accurate and safe placement of an OCS.
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Affiliation(s)
- Zhen-Qi Lou
- Department of Spinal Surgery, Ningbo No.6 Hospital, Ningbo, China.,School of Medicine, Ningbo University, Ningbo, China
| | - Yang Wang
- Department of Spinal Surgery, Ningbo No.6 Hospital, Ningbo, China
| | - Ding-Li Xu
- Department of Spinal Surgery, Ningbo No.6 Hospital, Ningbo, China.,School of Medicine, Ningbo University, Ningbo, China
| | - Guo-Qing Li
- Department of Spinal Surgery, Ningbo No.6 Hospital, Ningbo, China
| | - Wei-Hu Ma
- Department of Spinal Surgery, Ningbo No.6 Hospital, Ningbo, China
| | - Chao-Yue Ruan
- Department of Spinal Surgery, Ningbo No.6 Hospital, Ningbo, China
| | - Hua-Guo Zhao
- Department of Spinal Surgery, Ningbo No.6 Hospital, Ningbo, China
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Du YK, Li SY, Yang WJ, Wang XY, Bi YF, Dong J, Huang H, Gao F, Li GZ, Wei HW, Yang JK, Xi YM. Morphometric Trajectory Analysis for Occipital Condyle Screws. Orthop Surg 2020; 12:931-937. [PMID: 32495510 PMCID: PMC7307246 DOI: 10.1111/os.12700] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 03/31/2020] [Accepted: 04/20/2020] [Indexed: 11/30/2022] Open
Abstract
Objectives Occipitocervical fusion (OCF) is an effective treatment for instability of occipitocervical junction (OCJ). The occipital condyle screw serves as a novel surgical technique for occipitocervical fixation. However, the intraoperative procedures for the occipital condyle screw technique have relied on surgeons’ experience, so the pool of surgeons who are able to perform this surgery safely is limited. The present study aims to evaluate the feasibility and safety of the occipital condyle screw technique using human cadavers and to provide image anatomy for clinical application basis. Methods The scientific study comprised 10 fresh‐frozen cadaveric specimens from the anatomy department of Qingdao University. Placement of the occipital condyle screws (3.5 mm diameter and 20.0 mm length) was performed in the 10 fresh‐frozen cadaveric specimens with intact occipitocervical junctions, respectively. Occipitocervical CT was performed for all specimens and the DICOM data was obtained. Occipitocervical CT three‐dimensional (3D) reconstruction was performed for the cadavers. Morphometric analysis was performed on the bilateral occipitocervical junction of 10 cadaveric specimens based on the 3D reconstruction CT images. Detailed morphometric measurements of the 20 occipital condyles screws were conducted including the average length of the screw trajectory, inside and upper tilting angles of screws, distance to the hypoglossal canal, and to the medial wall of occipital condyle. Results Placement of the occipital condyle screws into the 20 occipital condyles of the 10 cadaveric specimens was performed successfully and the trajectory of implantation was satisfactory according to 3D CT reconstruction images, respectively. There was no obvious injury to the spinal cord, nerve root, and vertebral artery. The length of the bilateral screw trajectory was, respectively, 20.96 ± 0.91 mm (left) and 20.59 ± 0.77 mm (right) (t = 1.306, P > 0.05). The upper tilting angle of bilateral screws was, respectively, 11.24° ± 0.74° (left) and 11.11° ± 0.64° (right) (t = 0.681, P > 0.05). The inside tilting angle of bilateral screws was, respectively, 31.00° ± 1.32° (left) and 30.85° ± 1.27° (right) (t = 0.307, P > 0.05). The screw's distance to the bilateral hypoglossal canal was, respectively, 4.84 ± 0.54 mm (left) and 4.70 ± 0.54 mm (right) (t = 0.685, P > 0.05). The screw's distance to the medial wall of the bilateral occipital condyle was, respectively, 5.13 ± 0.77 mm (left) and 5.04 ± 0.71 mm (right) (t = 0.384, P > 0.05). Conclusion The occipital condyle screw technique can serve as a feasible and safe treatment for instability of the occipitocervical junction with meticulous preoperative planning of the screw entry point and direction based on individual differences. Morphometric trajectory analysis is also an effective way to evaluate the surgical procedure.
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Affiliation(s)
- Yu-Kun Du
- Department of Spinal Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Si-Yuan Li
- Department of Spinal Surgery, Shandong Provincial Third Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Wen-Jiu Yang
- Department of Spinal Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiang-Yang Wang
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Yi-Fang Bi
- The Sanatorium of Qingdao, Qingdao, China
| | - Jun Dong
- Department of Spinal Surgery, Shandong Provincial Hospital affiliated to Shandong University, Jinan, China
| | - Hui Huang
- Department of Spinal Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Feng Gao
- Department of Orthopaedics, Nanyang City Center Hospital
| | - Gui-Zhi Li
- Department of Spinal Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Hua-Wei Wei
- Department of Spinal Surgery, De Zhou People's Hospital, Dezhou, China
| | - Jian-Kun Yang
- Department of Spinal Surgery, Zhoukou Xiehe Orthopedic Hospital, Zhoukou, China
| | - Yong-Ming Xi
- Department of Spinal Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
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Atlanto-Occipital Transarticular Screw Fixation for the Treatment of Traumatic Occipitocervical Instability in the Pediatric Population. World Neurosurg 2020; 140:e81-e86. [PMID: 32344140 DOI: 10.1016/j.wneu.2020.04.129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/16/2020] [Accepted: 04/18/2020] [Indexed: 11/21/2022]
Abstract
BACKGROUND Atlanto-occipital transarticular screw fixation (AOTSF) has rarely been reported for fixation of the craniovertebral junction (CVJ). METHODS A retrospective chart review of all pediatric patients (less than 18 years of age) with an attempt of AOTSF for fixation of traumatic CVJ instability was conducted. RESULTS A total of 4 patients (2 boys and 2 girls; ages 2, 3, 5, and 8 years) who suffered from acute traumatic CVJ instability managed during 2007-2018 underwent an attempted AOTSF. In 2 patients, this method was technically successful. In the other 2 instances, we were not able to engage the screw into the occipital condyle. These were converted to standard occipital plate, rod, and screw fixation. All were placed in a halo subsequently for a minimum of 3 months. Three patients were fused at last follow-up (range, 17-48 months). One patient after successful AOTSF did not fuse. There were no surgical complications or revision procedures. CONCLUSIONS AOTSF was feasible in half of pediatric patients suffering from traumatic CVJ instability. Therefore, intraoperative salvage options and strategies should be on hand readily. In the pediatric population, where bony anatomy may pose challenges to fixation, this technique may offer a viable first-line option in selected cases, despite the overall modest success rate.
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Bosco A, Aleem I, La Marca F. Occipital condyle screws: indications and technique. JOURNAL OF SPINE SURGERY 2020; 6:156-163. [PMID: 32309654 DOI: 10.21037/jss.2020.03.01] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Occipitocervical instability is a life threatening and disabling disorder caused by a myriad of pathologies. Restoring the anatomical integrity and stability of the occipitocervical junction (OCJ) is essential to achieve optimal clinical outcomes. Surgical stabilization of the OCJ is challenging and technically demanding. There is a paucity of options available for anchorage in the cephalad part of the construct in occipitocervical fixation systems due to the intricate topography of the craniocervical junction combined with the risk of injury to the surrounding anatomical structures. Surgical techniques and instrumentation for stabilizing the unstable OCJ have undergone several modifications over the years and have primarily depended on occipital squama-based fixations. At present, the occipital-plate-screw-rod construct is the most commonly adopted technique of stabilizing the OCJ. In certain distinct scenarios like posterior fossa craniectomy (absence of occipital squama for screw placement), malignancy and infection of occipital squama (poor screw purchase in the diseased occipital bone) and in revision surgery for failed occipitocervical stabilization, occipital plate-based instrumentation is not feasible. To overcome these difficulties, recently, a novel technique of occipitocervical stabilization, using the occipital condyle (OC) as the cephalad anchor, namely the direct occipital condyle screw (OCS) fixation was described. Several cadaveric and biomechanical studies have suggested that OCSs are feasible options as additional augmentative anchors in a standard occipital plate-screw-rod construct or as salvage cephalad anchors in previous failed occipital-plate-screw-rod constructs. The OCS placement technique has a steep learning curve. We have done a review of the techniques of OCS fixation and have described the indications, biomechanical and technical considerations, preoperative planning, surgical technique, complications, advantages and limitations of OCS based occipitocervical fixation.
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Affiliation(s)
- Aju Bosco
- Assistant Professor in Orthopedics and Spine Surgery, Orthopedic Spine Surgery Unit, Institute of Orthopedics and Traumatology, Madras Medical College, Chennai, India
| | - Ilyas Aleem
- Department of Orthopedic Surgery, University of Michigan, 2912 Taubman Center, Ann Arbor, MI, USA
| | - Frank La Marca
- Professor of Neurological Surgery, Henry Ford Health System, Jackson, MI, USA
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Occipital Condyle Screw Placement in Patients with Chiari Malformation: A Radiographic Feasibility Analysis and Cadaveric Demonstration. World Neurosurg 2020; 136:470-478. [PMID: 32204299 DOI: 10.1016/j.wneu.2020.01.150] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 01/15/2020] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Patients who undergo decompression surgery for Chiari malformation frequently require occipitocervical fixation. This is typically performed with occipital plates, which may cause intracranial injuries due to multiple fixation points. We undertook this study to assess the feasibility of occipital condyle (OC) screw placement as an alternative method of occipitocervical fixation in this patient population. METHODS Using a cadaveric model with navigational assistance, we performed the complete surgical procedure for occipitocervical fixation with OC screws. We then performed a morphometric analysis using measurements from computed tomography scans of 49 patients (32 adult, 17 pediatric) who had undergone occipitocervical fusion with instrumentation following decompression surgery for Chiari malformation. Bilateral morphometric data were analyzed for the adult and pediatric subgroups separately, as well as for the overall group. RESULTS The surgical procedure was successfully performed in the cadaveric model, demonstrating the feasibility of the proposed method. Ninety-eight OCs were studied in the morphometric analysis, and 80 (81.6%) met our eligibility criteria for OC screw placement. However, in 14.1% of adult OCs and 26.5% of pediatric OCs studied, placement of condylar screws would have been challenging or unsafe, according to our criteria. CONCLUSIONS Our findings suggest that OC screws provide a useful option for occipitocervical fixation in a substantial proportion of patients with Chiari malformation. However, rigorous preoperative analysis would be essential to identify appropriate candidates for this technique and exclude those in whom it should not be attempted. Additional study is warranted.
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Gumussoy I, Duman SB. Morphometric analysis of occipital condyles using alternative imaging technique. Surg Radiol Anat 2019; 42:161-169. [PMID: 31549198 DOI: 10.1007/s00276-019-02344-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 09/14/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE The occipital condyles (OCs) are crucial anatomical structures in the cranial base. To our knowledge, there is no cone beam computed tomography (CBCT)-based study on the morphometric analysis of OCs. The aim of this study was to evaluate the morphometric analysis of OCs using CBCT. METHODS CBCT images of 200 OCs from 100 patients of which 39 males and 61 females in the age group of 18-67 years were included in the study population. Linear and angular measurements of OCs were performed. RESULTS The average OC width, length, height, sagittal angle, and effective height were 10.3 ± 1.3 mm, 19.6 ± 2.0 mm, 9.1 ± 1.4 mm, 7.4 ± 1.7 mm, and 35.3 ± 5.2 mm. Condylar width and sagittal angle measurements were found significantly different between the right and left sides; and were not found significant difference between the right and left sides in the measurements of condylar height, length, and effective height. Also the average intercondylar anterior distance (ICAD), intercondylar posterior distance (ICPD), distance between the basion and the anterior apex of the occipital condyle (B-AAOC), distance between the basion and posterior apex of the occipital condyle (B-PAOC), distance between the opisthion and anterior apex of occipital condyle (O-AAOC), and distance between the opisthion and posterior apex of occipital condyle (O-PAOC) were 20.9 ± 1.5 mm, 44.0 ± 2.0 mm, 12.3 ± 1.9 mm, 34.5 ± 4.2 mm, 29.8 ± 1.7 mm, and 27.0 ± 2.1 mm. There was not significant difference in the morphometric measurements among age groups. All morphometric measurements showed a significant difference depending on gender. CONCLUSIONS The morphometric evaluation of OCs may be effectively examined using CBCT. Linear and angular measurements data of OCs in the present study may be used as a reference database for future morphometric and surgical investigations.
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Affiliation(s)
- Ismail Gumussoy
- Department of Dentomaxillofacial Radiology, Faculty of Dentistry, Sakarya University, Sakarya, Turkey.
| | - Suayip B Duman
- Department of Dentomaxillofacial Radiology, Faculty of Dentistry, İnonu University, Malatya, Turkey
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Morphometric Evaluation of Occipital Condyles: Defining Optimal Trajectories and Safe Screw Lengths for Occipital Condyle-Based Occipitocervical Fixation in Indian Population. Asian Spine J 2018; 12:214-223. [PMID: 29713401 PMCID: PMC5913011 DOI: 10.4184/asj.2018.12.2.214] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 06/25/2017] [Accepted: 06/28/2017] [Indexed: 11/17/2022] Open
Abstract
Study Design Computed tomographic (CT) morphometric analysis. Purpose To assess the feasibility and safety of occipital condyle (OC)-based occipitocervical fixation (OCF) in Indians and to define anatomical zones and screw lengths for safe screw placement. Overview of Literature Limitations of occipital squama-based OCF has led to development of two novel OC-based OCF techniques. Methods Morphometric analysis was performed on the OCs of 70 Indian adults. The feasibility of placing a 3.5-mm-diameter screw into OCs was investigated. Safe trajectories and screw lengths for OC screws and C0–C1 transarticular screws without hypoglossal canal or atlantooccipital joint compromise were estimated. Results The average screw length and safe sagittal and medial angulations for OC screws were 19.9±2.3 mm, ≤6.4°±2.4° cranially, and 31.1°±3° medially, respectively. An OC screw could not be accommodated by 27% of the population. The safe sagittal angles and screw lengths for C0–C1 transarticular screw insertion (48.9°±5.7° cranial, 26.7±2.9 mm for junctional entry technique; 36.7°±4.6° cranial, 31.6±2.7 mm for caudal C1 arch entry technique, respectively) were significantly different than those in other populations. The risk of vertebral artery injury was high for the caudal C1 arch entry technique. Screw placement was uncertain in 48% of Indians due to the presence of aberrant anatomy. Conclusions There were significant differences in the metrics of OC-based OCF between Indian and other populations. Because of the smaller occipital squama dimensions in Indians, OC-based OCF techniques may have a higher application rate and could be a viable alternative/salvage option in selected cases. Preoperative CT, including three-dimensional-CT-angiography (to delineate vertebral artery course), is imperative to avoid complications resulting from aberrant bony and vascular anatomy. Our data can serve as a valuable reference guide in placing these screws safely under fluoroscopic guidance.
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Zhou J, Espinoza Orías AA, Kang X, He J, Zhang Z, Inoue N, An HS. CT-based morphometric analysis of the occipital condyle: focus on occipital condyle screw insertion. J Neurosurg Spine 2016; 25:572-579. [DOI: 10.3171/2016.4.spine151431] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE
The segmental occipital condyle screw (OCS) is an alternative fixation technique in occipitocervical fusion. A thorough morphological study of the occipital condyle (OC) is critical for OCS placement. The authors set out to introduce a more precise CT-based method for morphometric analysis of the OC as it pertains to the placement of the segmental OCS, and they describe a novel preoperative simulation method for screw placement. Two new clinically relevant parameters, the height available for the OCS and the warning depth, are proposed.
METHODS
CT data sets from 27 fresh-frozen human cadaveric occipitocervical spines were used. All measurements were performed using a commercially available 3D reconstruction software package. The length, width, and sagittal angle of the condyle were measured in the axial plane at the base of the OC. The height of the OC and the height available for the segmental OCS were measured in the reconstructed oblique sagittal plane, fitting the ideal trajectory of the OCS recommended in the literature. The placement of a 3.5-mm-diameter screw that had the longest length of bicortical purchase was simulated into the OC in the oblique sagittal plane, with the screw path not being blocked by the occiput and not violating the hypoglossal canal cranially or the atlantooccipital joint caudally. The length of the simulated screw was recorded. The warning depth was measured as the shortest distance from the entry point of the screw to the posterior border of the hypoglossal canal.
RESULTS
The mean length and width of the OC were found to be larger in males: 22.2 ± 1.7 mm and 12.1 ± 1.0 mm, respectively, overall (p < 0.0001 for both). The mean sagittal angle was 28.0° ± 4.9°. The height available for the OCS was significantly less than the height of the OC (6.2 ± 1.3 mm vs 9.4 ± 1.5 mm, p < 0.0001). The mean screw length (19.3 ± 1.9 mm) also presented significant sex-related differences: male greater than female (p = 0.0002). The mean warning depth was 7.5 ± 1.7 mm. In 7.4% of the samples, although the height of the OC was viable, the height available for the OCS was less than 4.5 mm, thus making screw placement impractical. For these cases, a new preoperative simulation method of the OCS placement was proposed. In 92.6% of the samples that could accommodate a 3.5-mm-diameter screw, 24.0% showed that the entry point of the simulated screw was covered by a small part of the C-1 posterosuperior joint rim.
CONCLUSIONS
The placement of the segmental OCS is feasible in most cases, but a thorough preoperative radiological analysis is essential and cannot be understated. The height available for the OCS is a more clinically relevant and precise parameter than the height of the OC to enable proper screw placement. The warning depth may be helpful for the placement of the OCS.
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Affiliation(s)
- Jinsong Zhou
- 1Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois
- 2Department of Orthopaedic Surgery, Chengdu Military General Hospital, Chengdu, Sichuan; and
| | | | - Xia Kang
- 2Department of Orthopaedic Surgery, Chengdu Military General Hospital, Chengdu, Sichuan; and
| | - Jade He
- 1Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois
| | - Zhihai Zhang
- 3Department of Orthopaedic Surgery, Aviation General Hospital, China Medical University, Beijing, People's Republic of China
| | - Nozomu Inoue
- 1Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois
| | - Howard S. An
- 1Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois
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Lee HJ, Choi DY, Shin MH, Kim JT, Kim IS, Hong JT. Anatomical feasibility for safe occipital condyle screw fixation. 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; 25:1674-82. [PMID: 26831538 DOI: 10.1007/s00586-016-4399-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 01/11/2016] [Accepted: 01/15/2016] [Indexed: 12/01/2022]
Abstract
PURPOSE The occipital condyle (OC) screw can be a viable alternative option for the occipito-cervical fixation. However, the risk of vertebral artery (VA) injury during the direct OC screw fixation has not been adequately assessed. The purpose of this study was to establish the course of the VA (V3) relative to the nearby osseous structures to estimate the feasibility of OC screw fixation and describe its anatomical relationship depending on patient's age and sex. METHODS A total of 387 three-dimensional computed tomographic angiograms (3D-CTA) were used and compared between two age groups. The vertebral artery diameter and two kinds of bony space were measured. The occipito-C1 arch space (O-C1S) and VA-occipital bone distance (VOD, six entry points) were measured on both sides. The feasibility of direct OC screw fixation can be represented by the VOD value; the minimum feasible value was determined to be 4 mm. Angular measurements (O-C1A and O-C2A) were also taken to assess their relationship to the bony space. RESULTS The mean value of the O-C1S ranged from 9.0 to 9.9 mm. The mean value of the VOD ranged from 3.2 to 3.5 mm, and the proportion of individuals for which direct OC screw fixation was considered feasible ranged from 32 to 42 % in both age groups and there was no significant difference between two age groups. The VOD value was not affected by laterality or by gender (P > 0.05). The mean kyphosis of the O-C1A (-5° ± 5.2°, range -22° to 8°) was significantly smaller in the young age group compared to the older age group (-7.6° ± 5.3°, range -26° to 2°). The mean lordosis of the O-C2A (12.4° ± 6.4°, range 3°-33°) was significantly higher in the young age group compared to the older age group (10.4° ± 6.4°, range 0°-36°). CONCLUSIONS The direct OC screw fixation was not possible in a considerable number of cases due to the limited space and the position of the VA regardless of age group. Only about one quarter (21-24 %) of all patients was affordable to place the direct OC screw bilaterally. There was more space available to place the direct OC screw when the angle of the upper cervical spine is more kyphotic.
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Affiliation(s)
- Ho Jin Lee
- Department of Neurosurgery, Incheon St. Mary's Hospital, The Catholic University of Korea, Incheon, Korea
| | - Doo Yong Choi
- Department of Neurosurgery, Incheon St. Mary's Hospital, The Catholic University of Korea, Incheon, Korea
| | - Myoung Hoon Shin
- Department of Neurosurgery, Incheon St. Mary's Hospital, The Catholic University of Korea, Incheon, Korea
| | - Jong Tae Kim
- Department of Neurosurgery, Incheon St. Mary's Hospital, The Catholic University of Korea, Incheon, Korea
| | - Il Sup Kim
- Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, 93-6 Ji-Dong, Paldal-gu, Suwon, 442-723, Korea
| | - Jae Taek Hong
- Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, 93-6 Ji-Dong, Paldal-gu, Suwon, 442-723, Korea.
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