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Tsirikos AI, Ahuja K, Khan M. Minimally Invasive Surgery for Adolescent Idiopathic Scoliosis: A Systematic Review. J Clin Med 2024; 13:2013. [PMID: 38610778 PMCID: PMC11012693 DOI: 10.3390/jcm13072013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/15/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
Background: Minimally invasive surgical (MIS) techniques have gained popularity as a safe and effective alternative to open surgery for degenerative, traumatic, and metastatic spinal pathologies. In adolescent idiopathic scoliosis, MIS techniques comprise anterior thoracoscopic surgery (ATS), posterior minimally invasive surgery (PMIS), and vertebral body tethering (VBT). In the current systematic review, the authors collected and analyzed data from the available literature on MIS techniques in AIS. Methods: The articles were shortlisted after a thorough electronic and manual database search through PubMed, EMBASE, and Google Scholar. Results: The authors included 43 studies for the review; 14 described the outcomes with ATS, 13 with PMIS, and 16 with VBT. Conclusions: While the efficacy of the ATS approach is well-established in terms of comparable coronal and sagittal correction to posterior spinal fusion, the current use of ATS for instrumented fusion has become less popular due to a steep learning curve, high pulmonary and vascular complication rates, implant failures, and increased non-union rates. PMIS is an effective alternative to the standard open posterior spinal fusion, with a steep learning curve and longer surgical time being potential disadvantages. The current evidence, albeit limited, suggests that VBT is an attractive procedure that merits consideration in terms of radiological correction and clinical outcomes, but it has a high complication and re-operation rate, while the most appropriate indications and long-term outcomes of this technique remain unclear.
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Affiliation(s)
- Athanasios I. Tsirikos
- Scottish National Spine Deformity Centre, Royal Hospital for Children and Young People, Edinburgh EH16 4TJ, UK; (K.A.); (M.K.)
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Kovacı H, Yetim AF, Çelik A. Biomechanical analysis of spinal implants with different rod diameters under static and fatigue loads: an experimental study. BIOMED ENG-BIOMED TE 2019; 64:339-346. [PMID: 29935109 DOI: 10.1515/bmt-2017-0236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 06/01/2018] [Indexed: 02/06/2023]
Abstract
Spinal implants are commonly used in the treatment of spinal disorders or injuries. However, the biomechanical analyses of them are rarely investigated in terms of both biomechanical and clinical perspectives. Therefore, the main purpose of this study is to investigate the effects of rod diameter on the biomechanical behavior of spinal implants and to make a comparison among them. For this purpose, three spinal implants composed of pedicle screws, setscrews and rods, which were manufactured from Ti6Al4V, with diameters of 5.5 mm, 6 mm and 6.35 mm were used and a bilateral vertebrectomy model was applied to spinal systems. Then, the obtained spinal systems were tested under static tension-compression and fatigue (dynamic compression) conditions. Also, failure analyses were performed to investigate the fatigue behavior of spinal implants. After static tension-compression and fatigue tests, it was found that the yield loads, stiffness values, load carrying capacities and fatigue performances of spinal implants enhanced with increasing spinal rod diameter. In comparison to spinal implants with 5.5 mm rods, the fatigue limits of implants showed 13% and 33% improvements in spinal implants having 6 mm and 6.35 mm rods, respectively. The highest static and fatigue test results were obtained from spinal implants having 6.35 mm rods among the tested implants. Also, it was observed that the increasing yield load and stiffness values caused an increase in the fatigue limits of spinal implants.
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Affiliation(s)
- Halim Kovacı
- Department of Mechanical Engineering, Engineering Faculty, Atatürk University, Erzurum 25240, Turkey
| | - Ali Fatih Yetim
- Department of Mechanical Engineering, Engineering and Architecture Faculty, Erzurum Technical University, Erzurum 25700, Turkey
| | - Ayhan Çelik
- Department of Mechanical Engineering, Engineering Faculty, Atatürk University, Erzurum 25240, Turkey
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Thoracoscopic Anterior Instrumentation and Fusion as a Treatment for Adolescent Idiopathic Scoliosis: A Systematic Review of the Literature. Spine Deform 2019; 6:384-390. [PMID: 29886908 DOI: 10.1016/j.jspd.2017.12.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 12/24/2017] [Accepted: 12/25/2017] [Indexed: 11/24/2022]
Abstract
STUDY DESIGN A systematic review and meta-analysis on thoracoscopic anterior instrumentation and fusion as a treatment for adolescent idiopathic scoliosis (AIS). OBJECTIVE The goal of this study is to determine the current status of thoracoscopic instrumentation and fusion as a treatment for AIS. SUMMARY OF BACKGROUND DATA Traditional surgical techniques for AIS have been open anterior thoracotomy with instrumentation and posterior spinal fusion and instrumentation. With the growing clinical interest in growth modulation surgeries, such as vertebral body tethering, there is a resurgence of interest in a thoracoscopic technique. METHODS The most commonly used medical databases (PubMed, Medline, EMBASE, CINAHL, and the Cochrane library) were searched up to November 2016 using the search terms VATS, thoracoscopic scoliosis, and thoracoscopic scoliosis instrumentation. RESULTS Thirteen studies met the strict inclusion criteria. Five hundred thirty patients were reported: 81.7% females, with the majority diagnosed as AIS. The mean operative time was 371.5 minutes, mean blood loss of 502.85 mL, and mean hospital stay of 5.9 days. Mean preoperative curve magnitude was 52.9°; postoperative curve magnitude was 17.9°, with a correction of 62.7%. Number of levels instrumented was 6.3, pulmonary function tests returned to preoperative values by 2 years postoperation, and the complication rate was 21.3%. Compared to thoracotomy, VATS had similar complication rates, blood loss, operation theater time, curve correction, and number of fused levels. Compared to posterior fusion, VATS has higher complication rates and operation theater time. Blood loss and percentage correction were similar. VATS had a smaller number of fused segments. CONCLUSIONS Advantages include less invasive, excellent curve correction, few levels fused, good satisfaction, and no long-term effect on pulmonary function. Drawbacks are increased operative time and incidence of pulmonary complications. With appropriate surgeon training and careful patient selection, this technique offers an acceptable alternative to the more traditional procedures. LEVEL OF EVIDENCE Level II.
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Pseudarthrosis in adult and pediatric spinal deformity surgery: a systematic review of the literature and meta-analysis of incidence, characteristics, and risk factors. Neurosurg Rev 2018; 42:319-336. [PMID: 29411177 DOI: 10.1007/s10143-018-0951-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/18/2018] [Accepted: 01/25/2018] [Indexed: 01/11/2023]
Abstract
We conducted a systematic review with meta-analysis and qualitative synthesis. This study aims to characterize pseudarthrosis after long-segment fusion in spinal deformity by identifying incidence rates by etiology, risk factors for its development, and common features. Pseudarthrosis can be a painful and debilitating complication of spinal fusion that may require reoperation. It is poorly characterized in the setting of spinal deformity. The MEDLINE, EMBASE, and Cochrane databases were searched for clinical research including spinal deformity patients treated with long-segment fusions reporting pseudarthrosis as a complication. Meta-analysis was performed on etiologic subsets of the studies to calculate incidence rates for pseudarthrosis. Qualitative synthesis was performed to identify characteristics of and risk factors for pseudarthrosis. The review found 162 articles reporting outcomes for 16,938 patients which met inclusion criteria. In general, the included studies were of medium to low quality according to recommended reporting standards and study design. Meta-analysis calculated an incidence of 1.4% (95% CI 0.9-1.8%) for pseudarthrosis in adolescent idiopathic scoliosis, 2.2% (95% CI 1.3-3.2%) in neuromuscular scoliosis, and 6.3% (95% CI 4.3-8.2%) in adult spinal deformity. Risk factors for pseudarthrosis include age over 55, construct length greater than 12 segments, smoking, thoracolumbar kyphosis greater than 20°, and fusion to the sacrum. Choice of graft material, pre-operative coronal alignment, post-operative analgesics, and sex have no significant impact on fusion rates. Older patients with greater deformity requiring more extensive instrumentation are at higher risk for pseudarthrosis. Overall incidence of pseudarthrosis requiring reoperation is low in adult populations and very low in adolescent populations.
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Izatt MT, Carstens A, Adam CJ, Labrom RD, Askin GN. Partial Intervertebral Fusion Secures Successful Outcomes After Thoracoscopic Anterior Scoliosis Correction: A Low-Dose Computed Tomography Study. Spine Deform 2015; 3:515-527. [PMID: 27927553 DOI: 10.1016/j.jspd.2015.04.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Revised: 02/13/2015] [Accepted: 04/17/2015] [Indexed: 11/27/2022]
Abstract
STUDY DESIGN Retrospective review of prospectively collected data. OBJECTIVES To analyze intervertebral (IV) fusion after thoracoscopic anterior spinal fusion (TASF) and explore the relationship between fusion scores and key clinical variables. SUMMARY OF BACKGROUND INFORMATION TASF provides comparable correction with some advantages over posterior approaches but reported mechanical complications, and their relationship to non-union and graft material is unclear. Similarly, the optimal combination of graft type and implant stiffness for effecting successful radiologic union remains undetermined. METHODS A subset of patients from a large single-center series who had TASF for progressive scoliosis underwent low-dose computed tomographic scans 2 years after surgery. The IV fusion mass in the disc space was assessed using the 4-point Sucato scale, where 1 indicates <50% and 4 indicates 100% bony fusion of the disc space. The effects of rod diameter, rod material, graft type, fusion level, and mechanical complications on fusion scores were assessed. RESULTS Forty-three patients with right thoracic major curves (mean age 14.9 years) participated in the study. Mean fusion scores for patient subgroups ranged from 1.0 (IV levels with rod fractures) to 2.2 (4.5-mm rod with allograft), with scores tending to decrease with increasing rod size and stiffness. Graft type (autograft vs. allograft) did not affect fusion scores. Fusion scores were highest in the middle levels of the rod construct (mean 2.52), dropping off by 20% to 30% toward the upper and lower extremities of the rod. IV levels where a rod fractured had lower overall mean fusion scores compared to levels without a fracture. Mean total Scoliosis Research Society (SRS) questionnaire scores were 98.9 from a possible total of 120, indicating a good level of patient satisfaction. CONCLUSIONS Results suggest that 100% radiologic fusion of the entire disc space is not necessary for successful clinical outcomes following thoracoscopic anterior selective thoracic fusion.
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Affiliation(s)
- Maree T Izatt
- Paediatric Spine Research Group, Institute of Health and Biomedical Innovation, Queensland University of Technology and Mater Health Services, Brisbane, Australia.
| | - Alan Carstens
- Paediatric Spine Research Group, Institute of Health and Biomedical Innovation, Queensland University of Technology and Mater Health Services, Brisbane, Australia
| | - Clayton J Adam
- Paediatric Spine Research Group, Institute of Health and Biomedical Innovation, Queensland University of Technology and Mater Health Services, Brisbane, Australia
| | - Robert D Labrom
- Paediatric Spine Research Group, Institute of Health and Biomedical Innovation, Queensland University of Technology and Mater Health Services, Brisbane, Australia
| | - Geoffrey N Askin
- Paediatric Spine Research Group, Institute of Health and Biomedical Innovation, Queensland University of Technology and Mater Health Services, Brisbane, Australia
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Selective thoracic fusion in AIS curves: the definition of target outcomes improves the prediction of spontaneous lumbar curve correction (SLCC). 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; 23:1263-81. [DOI: 10.1007/s00586-014-3280-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 03/10/2014] [Accepted: 03/13/2014] [Indexed: 10/25/2022]
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Chahoud J, Kanafani Z, Kanj SS. Surgical site infections following spine surgery: eliminating the controversies in the diagnosis. Front Med (Lausanne) 2014; 1:7. [PMID: 25705620 PMCID: PMC4335387 DOI: 10.3389/fmed.2014.00007] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Accepted: 03/13/2014] [Indexed: 12/19/2022] Open
Abstract
Surgical site infection (SSI) following spine surgery is a dreaded complication with significant morbidity and economic burden. SSIs following spine surgery can be superficial, characterized by obvious wound drainage or deep-seated with a healed wound. Staphylococcus aureus remains the principal causal agent. There are certain pre-operative risk factors that increase the risk of SSI, mainly diabetes, smoking, steroids, and peri-operative transfusions. Additionally, intra-operative risk factors include surgical invasiveness, type of fusion, implant use, and traditional instead of minimally invasive approach. A high level of suspicion is crucial to attaining an early definitive diagnosis and initiating appropriate management. The most common presenting symptom is back pain, usually manifesting 2–4 weeks and up to 3 months after a spinal procedure. Scheduling a follow-up visit between weeks 2 and 4 after surgery is therefore necessary for early detection. Inflammatory markers are important diagnostic tools, and comparing pre-operative with post-operative levels should be done when suspecting SSIs following spine surgery. Particularly, serum amyloid A is a novel inflammatory marker that can expedite the diagnosis of SSIs. Magnetic resonance imaging remains the diagnostic modality of choice when suspecting a SSI following spine surgery. While 18F-fluorodeoxyglucose-positron emission tomography is not widely used, it may be useful in challenging cases. Despite their low yield, blood cultures should be collected before initiating antibiotic therapy. Samples from wound drainage should be sent for Gram stain and cultures. When there is a high clinical suspicion of SSI and in the absence of superficial wound drainage, computed tomography-guided aspiration of paraspinal collections is warranted. Unless the patient is hemodynamically compromised, antibiotics should be deferred until proper specimens for culture are secured.
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Affiliation(s)
- Jad Chahoud
- Division of Infectious Diseases, Department of Internal Medicine, American University of Beirut Medical Center , Beirut , Lebanon
| | - Zeina Kanafani
- Division of Infectious Diseases, Department of Internal Medicine, American University of Beirut Medical Center , Beirut , Lebanon
| | - Souha S Kanj
- Division of Infectious Diseases, Department of Internal Medicine, American University of Beirut Medical Center , Beirut , Lebanon
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Abstract
BACKGROUND CONTEXT Spinal instrumentation has been used for more than five decades. Since the introduction of the Harrington rod in 1962, new rod materials and concepts have been developed. Rigid rod fixation has achieved higher fusion rates than previous methods. Recently, semirigid rod fixation devices have been used for both dynamic stabilization and fusion fixation. Memory rods, which have an interesting ability to return to their pre-bent shape when the temperature increases, are expected to be used for scoliosis correction. PURPOSE To review the previous literature regarding biofunctionality and biocompatibility of rods in spinal surgery. CONCLUSION The properties of each type of rod need to be taken into consideration when performing spinal instrumentation surgery.
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Affiliation(s)
- Hiroyuki Yoshihara
- Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E. 17th St, New York, NY 10003, USA; Department of Orthopaedic Surgery, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-Cho, Mizuho-Ku, Nagoya 467-8601, Japan.
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Surgical treatment of Lenke 1 main thoracic idiopathic scoliosis: results of a prospective, multicenter study. Spine (Phila Pa 1976) 2013; 38:328-38. [PMID: 22869062 DOI: 10.1097/brs.0b013e31826c6df4] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Prospective, consecutive, nonrandomized, multicenter study. OBJECTIVE The purpose of this study was to compare the outcomes of idiopathic scoliosis treatment for Lenke 1 curves with 3 treatment approaches. SUMMARY OF BACKGROUND DATA Surgical treatment options for Lenke 1 or primary main thoracic curve pattern in adolescent idiopathic scoliosis include thoracoscopic anterior spinal fusion, open anterior spinal fusion, and posterior spinal fusion (PSF) and instrumentation procedures. METHODS This was a prospective, consecutive, nonrandomized, multicenter study of surgical correction in adolescent idiopathic scoliosis. Patients with Lenke type 1 curve patterns from 7 sites were enrolled in this minimum 2-year follow-up study. Changes in pre- to postoperative radiographs, pulmonary function tests, Scoliosis Research Society questionnaire scores, and trunk rotation measures were compared. RESULTS A total of 149 patients (age: 14.5 ± 2 yr) were included (91% follow-up at 2 yr). The 3 groups were similar preoperatively in thoracic and lumbar curve size. There were 55 patients with thoracoscopic anterior spinal fusion, 17 patients with open anterior spinal fusion, and 64 patients with PSF. The fusion included on average 3 to 4 more levels in PSF than the 2 anterior approaches (P ≤ 0.001). Surgical time tended to be greater in the anterior groups by approximately 2 to 3 hours; however, blood loss was greatest with PSF. At 2 years, all 3 approaches showed similar improvements in the thoracic Cobb angle, coronal balance, the lumbar Cobb angle, Scoliosis Research Society questionnaire scores, and trunk rotation measures. The PSF approach resulted in overall reduction in kyphosis compared with the anterior approaches. Postoperative hyperkyphosis was an issue only in the 2 anterior groups. Major complication rates were similar. CONCLUSION All 3 approaches resulted in similarly satisfactory outcomes for the majority of patients with specific advantages to each technique. The patients with PSF had more levels fused, yet with the shortest operative time. The thoracoscopic anterior spinal fusion group had the smallest incisions and the lowest requirement for transfusion. The open anterior spinal fusion group had a modest loss of pulmonary function without any clear advantages compared with the other 2 groups. LEVEL OF EVIDENCE 2.
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Izatt MT, Adam CJ, Verzin EJ, Labrom RD, Askin GN. CT and radiographic analysis of sagittal profile changes following thoracoscopic anterior scoliosis surgery. SCOLIOSIS 2012; 7:15. [PMID: 22913616 PMCID: PMC3495407 DOI: 10.1186/1748-7161-7-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 08/10/2012] [Indexed: 12/02/2022]
Abstract
Background Previous studies report an increase in thoracic kyphosis after anterior approaches and a flattening of sagittal contours following posterior approaches. Difficulties with measuring sagittal parameters on radiographs are avoided with reformatted sagittal CT reconstructions due to the superior endplate clarity afforded by this imaging modality. Methods A prospective study of 30 Lenke 1 adolescent idiopathic scoliosis (AIS) patients receiving selective thoracoscopic anterior spinal fusion (TASF) was performed. Participants had ethically approved low dose CT scans at minimum 24 months after surgery in addition to their standard care following surgery. The change in sagittal contours on supine CT was compared to standing radiographic measurements of the same patients and with previous studies. Inter-observer variability was assessed as well as whether hypokyphotic and normokyphotic patient groups responded differently to the thoracoscopic anterior approach. Results Mean T5-12 kyphosis Cobb angle increased by 11.8 degrees and lumbar lordosis increased by 5.9 degrees on standing radiographs two years after surgery. By comparison, CT measurements of kyphosis and lordosis increased by 12.3 degrees and 7.0 degrees respectively. 95% confidence intervals for inter-observer variability of sagittal contour measurements on supine CT ranged between 5-8 degrees. TASF had a slightly greater corrective effect on patients who were hypokyphotic before surgery compared with those who were normokyphotic. Conclusions Restoration of sagittal profile is an important goal of scoliosis surgery, but reliable measurement with radiographs suffers from poor endplate clarity. TASF significantly improves thoracic kyphosis and lumbar lordosis while preserving proximal and distal junctional alignment in thoracic AIS patients. Supine CT allows greater endplate clarity for sagittal Cobb measurements and linear relationships were found between supine CT and standing radiographic measurements. In this study, improvements in sagittal kyphosis and lordosis following surgery were in agreement with prior anterior surgery studies, and add to the current evidence suggesting that anterior correction is more capable than posterior approaches of addressing the sagittal component of both the instrumented and adjacent non instrumented segments following surgical correction of progressive Lenke 1 idiopathic scoliosis.
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Affiliation(s)
- Maree T Izatt
- Paediatric Spine Research Group, Queensland University of Technology and Mater Health Services Brisbane Ltd, Queensland, Australia.
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Residual thoracic hypokyphosis after posterior spinal fusion and instrumentation in adolescent idiopathic scoliosis: risk factors and clinical ramifications. Spine (Phila Pa 1976) 2012; 37:200-6. [PMID: 21358571 DOI: 10.1097/brs.0b013e318216106c] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A retrospective review of clinical and radiographic data from a single-center, prospectively collected scoliosis database. OBJECTIVE To assess risk factors for persistent thoracic hypokyphosis after posterior spinal fusion and instrumentation (PSFI) for adolescent idiopathic scoliosis (AIS) and to compare clinical outcomes between patients with residual thoracic hypokyphosis and those with normal thoracic kyphosis after PSFI for AIS. SUMMARY OF BACKGROUND DATA AIS is characterized by thoracic hypokyphosis, which should be corrected at the time of surgical treatment. Risk factors for residual thoracic hypokyphosis and the clinical ramifications have not been studied. METHODS Radiographic and clinical assessments by using the Scoliosis Research Society-30 (SRS-30) and Spinal Appearance Questionnaire (SAQ) were done preoperatively and at 2 years. Patients were divided into 2 groups on the basis of a threshold of 20° of thoracic kyphosis measured between T5 and T12 at 2-year follow-up. RESULTS Risk factors for being hypokyphotic at 2 years were male sex (21.69% vs. 12.21%, P = 0.084), preoperative kyphosis (11.4° vs. 22.8°, P < 0.0001), and smaller preoperative main thoracic coronal curves (58.4° vs. 62.0°, P = 0.004). A total of 71.5% of patients instrumented with 6.35-mm rods had normal thoracic kyphosis at 2 years compared with 47.0% instrumented with 5.5-mm rods (P = 0.0043). All-pedicle screw constructs remained hypokyphotic compared with hook-based constructs (P = 0.035). Logistic regression analysis demonstrated 2 parameters associated with persistent thoracic hypokyphosis at 2 years: preoperative hypokyphosis and larger rod diameter. Both groups had similar clinical results on the SRS-30 at 2-year follow-up (P > 0.05). There was a small but statistically significant correlation between sagittal Cobb angle and clinical deformity at 2 years based on the sagittal components of the SAQ. CONCLUSION There are 2 risk factors that lead to thoracic hypokyphosis in AIS: preoperative hypokyphosis and use of a 5.5-mm-diameter rod. A larger-diameter rod should be considered when planning surgery for thoracic AIS, especially when there is preoperative hypokyphosis. Despite thoracic kyphosis measuring less than 20°, these patients did not have decreased clinical outcomes as measured by the SRS-30 or SAQ.
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Scheer JK, Tang JA, Deviren V, Acosta F, Buckley JM, Pekmezci M, McClellan RT, Ames CP. Biomechanical analysis of cervicothoracic junction osteotomy in cadaveric model of ankylosing spondylitis: effect of rod material and diameter. J Neurosurg Spine 2011; 14:330-5. [DOI: 10.3171/2010.10.spine1059] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Ankylosing spondylitis (AS) is a genetic condition that frequently results in spinal sagittal plane deformity of thoracolumbar or cervicothoracic junctions. Generally, a combination of osteotomy and spinal fixation is used to treat severe cases. Although surgical techniques for traumatic injury across the cervicothoracic junction have been well characterized in clinical and biomechanical literature, the specific model of instrumented opening wedge osteotomy in autofused AS has not been studied biomechanically. This study characterizes the structural stability of various posterior fixation techniques across the cervicothoracic junction in spines with AS, specifically considering the effects of posterior rod diameter and material type.
Methods
For each of 10 fresh-frozen human spines (3 male, 7 female; mean age 60 ± 10 years; C3–T6), an opening wedge osteotomy was performed at C7–T1. Lateral mass screws were inserted bilaterally from C-4 to C-6 and pedicle screws from T-1 to T-3. For each specimen, 3.2-mm titanium (Ti), 3.5-mm Ti, and 3.5-mm cobalt chromium (CoCr) posterior spinal fusion rods were tested. To simulate the anterior autofusion and long lever arms characteristic of AS, anterior cervical plates were placed from C-4 to C-7 and T-1 to T-3 using fixed angle screws. Nondestructive flexion-extension, lateral bending, and axial rotation tests were conducted to 3.0 Nm in each anatomical direction; 3D motion tracking was used to monitor primary range of motion across the osteotomy (C7–T1). Biomechanical tests used a repeat-measures test design. The order of testing for each rod type was randomized across specimens.
Results
Constructs instrumented with 3.5-mm Ti and 3.5-mm CoCr rods were significantly stiffer in flexion-extension than those with the 3.2-mm Ti rod (25.2% ± 16.4% and 48.1% ± 15.3% greater than 3.2-mm Ti, respectively, p < 0.05). For axial rotation, the 3.5-mm Ti and 3.5-mm CoCr constructs also exhibited a significant increase in rigidity compared with the 3.2-mm Ti construct (36.1% ± 12.2% and 52.0% ± 20.0%, respectively, p < 0.05). There were no significant differences in rigidity seen between the 3 types of rods in lateral bending (p > 0.05). The 3.5-mm CoCr rod constructs showed significantly higher rigidity in flexion-extension than the 3.5-mm Ti rod constructs (33.1% ± 15.5%, p < 0.05). There was a trend for 3.5-mm CoCr to have greater rigidity in axial rotation (36.2% ± 18.6%), but this difference was not statistically significant (p > 0.05).
Conclusions
The results of this study suggest that 3.5-mm CoCr rods are optimal for achieving the most rigid construct in opening wedge osteotomy in the cervicothoracic region of an AS model. Rod diameter and material properties should be considered in construct strategy. Some surgeons have advocated anterior plating in patients with AS after osteotomy for additional stability and bone graft surface. Although this effect was not examined in this study, additional posterior stability achieved with CoCr may decrease the need for additional anterior procedures.
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Affiliation(s)
- Justin K. Scheer
- 1Biomechanical Testing Facility, Orthopaedic Trauma Institute, San Francisco General Hospital; and
- 2Departments of Orthopaedic Surgery and
| | - Jessica A. Tang
- 1Biomechanical Testing Facility, Orthopaedic Trauma Institute, San Francisco General Hospital; and
- 2Departments of Orthopaedic Surgery and
| | - Vedat Deviren
- 1Biomechanical Testing Facility, Orthopaedic Trauma Institute, San Francisco General Hospital; and
- 2Departments of Orthopaedic Surgery and
| | - Frank Acosta
- 1Biomechanical Testing Facility, Orthopaedic Trauma Institute, San Francisco General Hospital; and
- 3Neurological Surgery, University of California, San Francisco, California
| | - Jenni M. Buckley
- 1Biomechanical Testing Facility, Orthopaedic Trauma Institute, San Francisco General Hospital; and
- 2Departments of Orthopaedic Surgery and
| | - Murat Pekmezci
- 1Biomechanical Testing Facility, Orthopaedic Trauma Institute, San Francisco General Hospital; and
- 2Departments of Orthopaedic Surgery and
| | - R. Trigg McClellan
- 1Biomechanical Testing Facility, Orthopaedic Trauma Institute, San Francisco General Hospital; and
- 2Departments of Orthopaedic Surgery and
| | - Christopher P. Ames
- 1Biomechanical Testing Facility, Orthopaedic Trauma Institute, San Francisco General Hospital; and
- 3Neurological Surgery, University of California, San Francisco, California
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Kim HS, Park JO, Nanda A, Kho PA, Kim JY, Lee HM, Moon SH, Ha JW, Ahn EK, Shin DE, Kim SJ, Moon ES. Video-assisted thoracoscopic surgery for correction of adolescent idiopatic scoliosis: comparison of 4.5 mm versus 5.5 mm rod constructs. Yonsei Med J 2010; 51:753-60. [PMID: 20635452 PMCID: PMC2908885 DOI: 10.3349/ymj.2010.51.5.753] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
PURPOSE The purpose of this study is to report the comparative results of thoracoscopic correction achieved via cantilever technique using a 4.5 mm thin rod and the poly-axial reduction screw technique using a 5.5 mm thick rod in Lenke type 1 adolescent idiopathic scoliosis (AIS). MATERIALS AND METHODS Radiographic data, Scoliosis Research Society (SRS) patient-based outcome questionnaires, and operative records were reviewed for forty-nine patients undergoing surgical treatment of scoliosis. The study group was divided into a 4.5 mm thin rod group (n = 24) and a 5.5 mm thick rod group (n = 25). The radiographic parameters that were analyzed included coronal curve correction, the most caudal instrumented vertebra tilt angle correction, coronal balance, and thoracic kyphosis. RESULTS The major curve was corrected from 49.8 degrees and 47.2 degrees pre-operatively to 24.5 degrees and 18.8 degrees at the final follow-up for the thin and thick rod groups, respectively (50.8% vs. 60.2% correction). There were no significant differences between the two groups in terms of kyphosis, coronal balance, or tilt angle at the time of the final follow-up. The mean number of levels fused was 6.2 in the thin rod group, compared with 5.9 levels in the thick rod group. There were no major intraoperative complications in either group. CONCLUSION Significant correction loss was observed in the thin rod system at the final follow-up though both groups had comparable correction immediately post-operative. Therefore, the thick rod with poly axial screw system helps to maintain post-operative correction.
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Affiliation(s)
- Hak Sun Kim
- Department of Orthopaedic Surgery, Yonsei University College of Medicine, Seoul, Korea
| | - Jin Oh Park
- Department of Orthopaedic Surgery, Yonsei University College of Medicine, Seoul, Korea
| | - Ankur Nanda
- Department of Orthopaedic Surgery, Yonsei University College of Medicine, Seoul, Korea
| | - Phillip Anthony Kho
- Department of Orthopaedic Surgery, Yonsei University College of Medicine, Seoul, Korea
| | - Jin Young Kim
- Department of Orthopaedic Surgery, Yonsei University College of Medicine, Seoul, Korea
| | - Hwan Mo Lee
- Department of Orthopaedic Surgery, Yonsei University College of Medicine, Seoul, Korea
| | - Seong Hwan Moon
- Department of Orthopaedic Surgery, Yonsei University College of Medicine, Seoul, Korea
| | - Jung Won Ha
- Department of Orthopaedic Surgery, National Health Insurance Corporation Ilsan Hospital, Goyang, Korea
| | - Eun Kyoung Ahn
- Department of Anesthesiology and Pain Medicine, National Health Insurance Corporation Ilsan Hospital, Goyang, Korea
| | - Dong Eun Shin
- Department of Orthopaedic Surgery, CHA University, Pocheon, Korea
| | - Sung Jun Kim
- Department of Radiology, Yonsei University College of Medicine, Seoul, Korea
| | - Eun Su Moon
- Department of Orthopaedic Surgery, Yonsei University College of Medicine, Seoul, Korea
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14
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Newton PO. Thoracoscopic anterior instrumentation for idiopathic scoliosis. Spine J 2009; 9:595-8. [PMID: 19560052 DOI: 10.1016/j.spinee.2009.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Accepted: 05/08/2009] [Indexed: 02/09/2023]
Abstract
Lonner BS, Auerbach JD, Levin R, et al. Thoracoscopic anterior instrumented fusion for adolescent idiopathic scoliosis with emphasis on the sagittal plane. Spine J 2009;9:523-9 (this issue).
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