Management of subaxial cervical spine fracture in patients with ankylosing spondylitis: a retrospective study

Management of subaxial cervical spine fracture in patients with ankylosing spondylitis: a retrospective study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Management of subaxial cervical spine fracture in patients with ankylosing spondylitis: a retrospective study Haopeng Luan, Kai Liu, Yao Wang, Weibin Sheng, Maierdan Maimaiti, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1508247/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background: To assess the efficacy of anterior, posterior, and combined anterior and posterior surgery in the treatment of patients with ankylosing spondylitis (AS) combined with subaxial cervical spine fracture (SCSF). Methods: From January 2010 to January 2019, the medical records and imaging films of patients with AS combined with SCSF treated by anterior, posterior, and combined anterior and posterior bone grafting, and fusion using open reduction and internal fixation (ORIF) were assessed retrospectively. The demographic data, duration of AS, mechanism of injury, fracture type, bone fusion time, follow-up time, and complications were recorded. Postoperative neurological recovery of the patients was assessed and compared according to the ASIA classification. Results: A total of 37 patients with AS combined with SCSF were successfully treated by surgery, with a mean follow-up time of 39.4 ± 8.6 months. Eleven patients were managed by the anterior surgery, posterior surgery for 13 patients, and combined anterior and posterior surgery for 13 patients, with a mean bone fusion time of 8.5 ± 2.2 months. At the final follow-up, there was a statistical difference in ASIA grade between the preoperative and postoperative ( P < 0.05). Twenty-four cases were improved to grade E (64.8%), and 10 cases were improved to grade D (27%). The incidence of complications was 8.1% (3/37). Conclusions: Combined anterior and posterior surgery was a practical method for the treatment of patients with severe osteoporosis and neurological compression symptoms, three-column fracture combined with sagittal imbalance. ankylosing spondylitis fracture internal fixation subaxial cervical spine surgery Figures Figure 1 Figure 2 Figure 3 Background Ankylosing spondylitis (AS) is a rheumatic spondyloarthritides, characterized by an invasion of axial skeletons such as the spine and sacroiliac joints [ 1 ]. Mostly, the lesion progress from the sacroiliac joint to the paraspinal ligaments, facets, and peripheral joints along the central axis of the spine. Ossification of the intervertebral discs and ligaments usually takes place in the advanced stage, which results in long-segment fusion (“bamboo” spine), and ultimately severe spinal deformity [ 2 ]. Because of the above pathological changes and secondary osteoporosis, spinal elasticity and compliance may be reduced by AS, which may cause spinal fractures by even slight external forces. The risk of fractures in patients with AS is 3.3 times that the normal, with an incidence of approximately 10% in AS [ 3 ]. The spinal fractures with AS are mostly at the lower cervical spine (approximately 80%), which are unstable cervical fractures through the three columns of the spine, and are easily associated with severe cervical spinal cord injury [ 4 – 6 ]. At present, surgical treatment for patients with AS combined with lower cervical spine fracture (SCSF) involving the three columns is recommended [ 4 – 6 ], including anterior, posterior, and combined anterior and posterior surgery. Anterior surgery is not an appropriate option for patients with severe spinal cord compression symptoms, but posterior surgery in the treatment of anterior column vertebral collapse cannot receive stable fixation. Therefore, the surgical treatment of AS with lower cervical spine fractures is still a tremendous challenge for orthopedic surgeons. In this study, we retrospectively analyzed the clinical outcomes of patients with AS combined with SCSF treated by three approaches of surgery and explored the indications and surgical pitfalls. Methods From January 2010 to January 2019, the medical records and imaging films were assessed retrospectively of patients with AS combined with SCSF treated by anterior, posterior, or combined anterior and posterior approach of bone grafting, and fusion using open reduction and internal fixation (ORIF). This study was conducted after receiving written informed consent from participants and approval from the Ethics Committee of our institution. Inclusion criteria are as follows: Key hallmarks of AS diagnosed by the Modified New York Criteria [ 7 ]; positive for HLA-B27 antigens; the classical appearance of a bamboo spine (squared vertebra); SCSF certified by radiographs; managed by bone grafting, and fusion using ORIF. Patients were excluded for incomplete medical records, poor compliance, comorbidities (severe heart failure, kidney or liver disease), or follow-up time less than two years. Surgical technique The patient was placed in the supine position. After the general anesthesia, the junction between 2 cm of the upper edge of both ears was screwed into the screw, and the cranial traction arch was installed. The patient was placed in the prone position, and a transverse surgical incision was performed in the left anterior neck. When a combined anterior and posterior surgery performed, the cervical spine was fixed with a neck collar or neck circumference to change the surgical position as the head frame was removed. Posterior surgery was preceded using a midline incision. Simultaneously, a head frame and proper flexion were applied to expose the cervico-occipital region. When changing position, the laryngeal nerve and esophagus were easily damaged by changes in the cervical curve. The procedure must be performed carefully to avoid excessive distraction. The space between the cervical vascular sheath and the organ sheath was pulled apart, the anterior vertebral fascia was incised layer by layer. And the affected vertebral body was located by fluoroscopy. The ruptured intervertebral disc was removed, and the intervertebral disc in the upper and lower spaces of the fractured vertebral body was removed with nucleus pulposus forceps and a curette to the uncovertebral joints on both sides. The posterior longitudinal ligament was preserved, and a suitable bone spacer or allogeneic bone was placed, where the anterior column was fixed with a cervical titanium plate. Similarly, the affected posterior column was fixated by the pedicle screw when the posterior surgery was performed. After that, the internal fixator position was checked using fluoroscopy until a satisfactory position was received. The surgical area was flushed, negative pressure drainage was placed, and closed the incision. Postoperative management The drainage tube was removed when the fluid volume of the surgical area was less than 50 ml/24 hours. Patients were encouraged to wear a neck collar and walk using a walking aid to prevent pressure ulcers. After discharge, bone healing was assessed by the X-ray, and CT at 3, 6, and 12 postoperative months. Data Collection and Outcome Evaluation The demographic data, duration of AS, mechanism of injury, fracture type, intraoperative blood loss, operation time, bone fusion time, follow-up time, and complications were recorded. Postoperative neurological recovery of the patients was assessed by the ASIA classification. Statistical analysis Data were input in a Microsoft Excel spreadsheet (Redmond, WA, USA) and reported as mean and standard deviation, which were analyzed by the Mann-Whitney U test using the SPSS 20.0 software package (Chicago, IL, USA). Statistical significance was p < 0.05. Results Basic data of 37 patients with AS combined with SCSF were summarized in Table 1 , with a mean follow-up time of 39.4 ± 8.6 months. There were 25 cases caused by high-energy injury (vehicle accident), and 12 cases caused by falling or direct trauma. Eleven patients were managed by the anterior surgery (Fig. 1 ), with a mean operation time and blood loss of 145.7 ± 37.3 min and 354.2 ± 58.2 ml respectively. The posterior surgery was performed for 13 patients (Fig. 2 ), with a mean operation time and blood loss of 174.7 ± 57.6 min and 476.6 ± 108.2 ml respectively. Thirteen patients received combined anterior and posterior surgery (Fig. 3 ), with a mean operation time and blood loss of 254.3 ± 65.4 min and 697.6 ± 176.3 ml respectively. No intraoperative injury of the spinal cord, nerve root, or vertebral artery occurred. Table 1 Summary of clinical data in 37 patients Number Age (years) Gender Duration of AS (years) Segment Fracture type Dislocation Approach ASIA grade Follow-up time (months) Bone fusion(months) Preoperative Postoperative* 1 75 M 25 C5-C6 B Grade I posterior C E 53 11 2 64 M 24 C3-C4 A NO anterior D E 31 9 3 71 M 27 C4-C5 B Grade I AP B D 34 7 4 37 M 15 C6-C7 B NO posterior C E 36 11 5 63 F 26 C3-C4 A Grade I AP D E 31 6 6 60 M 24 C5-C6 B NO posterior D E 41 7 7 41 M 13 C3-C4 C Grade II AP A A 35 7 8 62 M 18 C4-C5 A NO anterior E E 25 6 9 53 M 19 C5-C6 C Grade I AP B D 39 8 10 63 M 14 C5-C6 B NO posterior C E 32 6 11 51 M 18 C3-C4 A NO anterior D E 55 13 12 64 M 16 C5-C6 D Grade I AP D E 50 10 13 58 M 20 C4-C5 A NO anterior C E 29 10 14 51 M 17 C5-C6 C NO posterior D E 30 7 15 57 M 16 C4-C5 A Grade I AP B D 50 13 16 57 M 20 C5-C6 A NO anterior C E 48 7 17 49 F 13 C6-C7 A Grade I posterior E E 54 8 18 57 M 15 C4-C5 C Grade II AP A A 51 10 19 64 M 22 C5-C6 B Grade I posterior D E 43 11 20 41 M 14 C5-C6 B NO posterior D E 33 7 21 51 M 19 C5-C6 D Grade II AP B B 36 9 22 45 M 16 C4-C5 C Grade I posterior D E 31 8 23 64 M 25 C6-C7 A NO anterior D E 41 11 24 50 M 15 C5-C6 D Grade I AP C D 40 7 25 62 M 28 C5-C6 A NO anterior D E 64 8 26 38 M 12 C6-C7 B Grade I posterior C E 37 6 27 49 F 14 C5-C6 B NO posterior D E 40 6 28 54 M 12 C3-C4 A NO anterior E E 42 6 29 52 M 17 C6-C7 C Grade II AP C E 47 10 30 55 M 20 C5-C6 A NO anterior C E 27 14 31 44 M 10 C4-C5 C Grade II AP B D 38 10 32 70 M 13 C4-C5 C Grade I AP D E 29 4 33 40 M 17 C5-C6 B NO posterior C E 46 10 34 44 M 13 C4-C5 A NO anterior D E 18 10 35 44 M 21 C5-C6 B Grade I posterior B D 38 7 36 55 M 16 C4-C5 A NO anterior D E 30 9 37 78 M 27 C6-C7 C Grade II AP C D 41 8 * P < 0.05, Mann-Whitney U test, compared with the preoperative. Preoperatively, according to the ASIA classification, there were 2 cases of grade A, 6 cases of grade B, 11 cases of grade C, 15 cases of grade D, and 3 cases of grade E. Twenty-four cases were improved to grade E (64.8%), 10 cases were improved to grade D (27%). Three patients were postoperatively assessed as grade A since severe vertebral destruction and spinal cord nerve injury. All patients were managed by bone grafting at the fracture area, with a mean bone fusion time of 8.5 ± 2.2 months. At the final follow-up, there was a statistical difference in ASIA grade between the preoperative and postoperative ( P < 0.05). Postoperative complications occurred in 3 patients, including cerebrospinal fluid leakage, delayed wound healing, and pulmonary infection. And the above complications were resolved using antibiotics and a dressing change. The satisfactory bone union was obtained at the final follow-up, without internal fixator re-displacement or dislocation. Discussion In this study, 37 patients with AS combined with SCSF were successfully treated by the three approaches of bone grafting, fusion and ORIF. The purpose of the surgery was to decompress the compression symptoms of the spinal cord effectively, restore and stabilize the bone rupture, and promote bone union. Twenty-four cases were improved to grade E (64.8%), and 10 cases were improved to grade D (27%), according to ASIA classification. The incidence of complications was 8.1% (3/37). In the patients with AS, extensive joint and ligament ossification usually affected the axial skeleton of the spine, such as ankylosis, kyphotic deformity, and osteoporosis [ 5 , 6 , 8 ]. In particular, the force line of the lower cervical may be destroyed by daily neck activities, which caused the vertebrae fracture. However, AS with SCSF is commonly misdiagnosed since the preexisting pain and kyphotic deformity [ 7 , 9 ]. Besides, SCSF was caused by lower energy trauma, because the vertebral osteoporosis caused by AS reduced spinal flexibility. Via published articles [ 5 ], SCSF mostly neared the cervico-thoracic junction and involved three columns of the spine, which were so unstable to associate with vertebrae dislocation, nerve compression symptoms, and respiratory complications. Westerveld et al. [ 10 ] found that the incidence of spinal cord injury in patients with AS combined with spine fracture was significantly higher than in a patient without AS (four times). In this study, high-energy trauma was the main cause of SCSF (67.5%), which affected three-column of vertebrae in 14 cases. Besides, 34 patients were associated with neurological injury, and the longer the duration of AS, the more severe the nerve injury. Therefore, CT and MRI were recommended to be applied to diagnose AS with SCSF at the early stage, especially for patients with a history of high-energy trauma. The primary treatment of AS with SCSF was to restore the fractured ends and stabilize the spinal sagittal balance [ 5 , 7 , 11 ]. Nonsurgical treatment was limited to simple fractures without involving the three columns of the vertebrae and displacement, such as fixation using a Halo brace for 10 to 16 weeks [ 12 ]. Surgical treatment (ORIF) was necessary for patients with unstable fractures involving the three columns, spinal cord injury, vertebral disc incarceration, and the presence of sagittal or coronal imbalance [ 12 – 14 ]. Its advantage was to stabilize the lower cervical sequence to promote bone union and decompress the spinal cord compression symptoms. The approach of surgery included anterior, posterior, and combined anterior and posterior. The clinical efficacy of the anterior surgery remained controversial, although its advantages of complete decompression and satisfactory bone union. Kouyoumdjian et al. [ 15 ] reported 19 patients with AS combined with SCSF were successfully treated by the anterior surgery and concluded that the lengthened internal titanium plates should be used in the anterior surgery to effectively resist abnormal stresses to receive satisfactory stabilization. However, Najib and Xiang et al. [ 16 , 17 ]considered that the anterior surgery was only suitable for SCSF with anterior and middle columns affected, whereas it had a poor ability to resist torsion and bending. In this cohort, 11 patients were performed anterior surgery and received a good bone fusion. We concluded that it was difficult to intraoperatively place the prone position in patients with kyphosis, which easily led to the iatrogenic fracture of the vertebral body and aggravated spinal cord injury. Hence, the anterior surgery could be preferred for patients with severe kyphotic deformity. If completely reducing the fracture cannot be received, an additional posterior surgery was recommended to prevent the failure of ORIF caused by the anterior stress concentration. Based on the satisfactory results of the anterior surgery in our patients, it was an effective option for patients without severe anterior column injury, disc fragmentation, and deformity. The posterior surgery had been certified its good biomechanical stability and reduction of the fracture, which was mainly suitable for fractures with the good axial load-bearing function of the anterior column, especially for fractures with dislocation and facet joint twist-lock [ 5 , 16 , 18 ]. Taggard et al. [ 19 ] reported 7 patients with AS combined SCSF were effectively managed by the posterior surgery, which improved the neurological compression symptoms at the final follow-up. Liang et al. [ 20 ] found that the posterior surgery using pedicle screw fixation and autologous bone grafting could play a critical role in stabilizing the spinal sagittal balance, correcting kyphosis, and relieving spinal cord compression. However, its shortcomings were mainly limited to dealing with anterior column fracture and compression, because the injured intervertebral disc was difficult to be removed [ 5 ]. Thirteen patients in this study were conducted by posterior surgery and obtained good outcomes of spinal sagittal balance and neurological improvement. As far as we were considered, the posterior surgery could receive stronger stability than the anterior [ 21 ], since the strong pedicle screws belonged to three-column fixation. However, its decompression of spinal cord compression caused by anterior protrusion into the spinal canal was worse than the anterior surgery. Besides, it should be in consideration that AS combined with severe osteoporosis, which was recommended that the internal fixation included 2 to 3 upper and lower vertebral bodies around the affected vertebrae respectively to resist the stress concentration caused by ankylosing segment. The combined anterior and posterior surgery was mainly indicated for patients with severe osteoporosis, three-column injury, dislocation, and spinal cord compression. Via published studies [ 6 ], satisfactory bone union with the improvement of spinal cord compression could be obtained by combined anterior and posterior surgery. For instance, Olerud and He et al. [ 8 , 22 ] presented a total of 41 patients with AS combined with SCSF successfully treated by combined anterior and posterior surgery, and considered that this method was a practical tool to treat SCSF with significant vertebral collapse and lack of anterior column support. Einsiedel et al. [ 23 ] found that there were approximately half of patients with the secondary displacement of the fracture end after anterior surgery, and they proposed that combined anterior and posterior surgery was ought to effectively decompress the spinal cord compression, especially vertebrectomy. Besides, whether anterior or posterior side surgery was performed firstly was still controversial. Some scholars believed that fractures of the anterior column mostly affected the intervertebral disc, in which there was nucleus pulposus tissue to reduce the possibility of self-fusion [ 4 , 7 , 11 , 23 ]. It was necessary to perform posterior surgery firstly to provide stability to complete anterior decompression and ORIF [ 18 ]. Others pointed out that the order of combined surgery depended on the efficacy of skull traction [ 5 ]. Anterior surgery could be performed firstly as a satisfactory reduction, but posterior surgery should be performed initially in case of the failure of reduction. In our cohort, 13 patients were effectively managed by a one-stage combined anterior and posterior surgery and improved their severe neurological deficits. In our opinion, the first step should be conducted on the side with a simple type of fracture and mild neurological symptoms. The affected anterior column of 10 patients was fixated firstly using a titanium plate to provide stability for resolving the injured intervertebral disc and fracture. And posterior surgery was performed firstly on 3 patients. Surgery was just the beginning and not the end of the treatment. Postoperative management and strategies for complications were equally important. In this cohort, complications occurred in 3 patients after combined anterior and posterior ORIF, including intraoperative dural tear, delayed wound healing, and pulmonary infection. Fortunately, complications were resolved using antibiotics and dressing changes. It can be concluded that the risk of intraoperative trauma and complications were brought out by the combined surgery. Hence, orthopedics should pay more attention to the surgical indication for AS combined with SCSF, and choose a practical method according to the affected vertebrae column. The limitations caused by the small-sample, single-medical-center, retrospective study existed in this study. Further, a comparison between the efficacy of different surgical approaches was not performed since the small number of cases. Conclusion Surgical strategies for patients with AS combined with SCSF should comprehensively consider the type of injury and fracture, severe osteoporosis, spine sagittal balance, neurological compression symptoms, and deformity. Combined anterior and posterior surgery was a practical method for the treatment of patients with severe osteoporosis and neurological compression symptoms, three-column fracture combined with sagittal imbalance. Declarations Ethics approval and consent to participate This retrospective study was approved by the Ethics Committee of the First Affiliated Hospital of Xinjiang Medical University and carried out in accordance with the ethical standards set out in the Helsinki Declaration. Informed consent was received from all participants. Consent for publication Not applicable. Availability of data and materials The data sets generated and analyzed during the current study are not publicly available due to restrictions on ethical approvals involving patient data and anonymity but can be obtained from the corresponding author on reasonable request. Competing interests The authors declare that they have no conflict of interest. Funding This study was not funded by any foundation. Author Contributions HPL, KL, YW, and QD developed the research questions and scope of the study. HPL, YW, and WBS conducted preoperative and postoperative data screening, and data charting. HPL drafted the manuscript, prepared tables, and figures with KL’s contribution. QD, WBS, and MM developed the literature search strategies in collaboration with the other authors. HPL, KL, YW, and WBS contributed to the organization, analysis, and interpretation of the results. All authors read and approved the final manuscript. Acknowledgments Not applicable. References Koller H, Koller J, Mayer M, Hempfing A, Hitzl W: Osteotomies in ankylosing spondylitis: where, how many, and how much? EUR SPINE J 2018, 27 (Suppl 1):70–100. Braun J, Sieper J: Ankylosing spondylitis . LANCET 2007, 369 (9570):1379–1390. Davey-Ranasinghe N, Deodhar A: Osteoporosis and vertebral fractures in ankylosing spondylitis . CURR OPIN RHEUMATOL 2013, 25 (4):509–516. Tse M, Tsai Y, Yang L, Jaw F, Lin C: Management of cervical fractures in ankylosing spondylitis patients: immediate fixation effort via vertebroplasty with one-staged combined anterior and posterior fixation . BRIT J NEUROSURG 2020:1–6. 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Einsiedel T, Schmelz A, Arand M, Wilke H, Gebhard F, Hartwig E, Kramer M, Neugebauer R, Kinzl L, Schultheiss M: Injuries of the cervical spine in patients with ankylosing spondylitis: experience at two trauma centers . Journal of neurosurgery. Spine 2006, 5 (1):33. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-1508247","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":97108563,"identity":"01a16e44-55d6-4099-88f5-9dd40e5c4407","order_by":0,"name":"Haopeng Luan","email":"","orcid":"","institution":"The First Affiliated Hospital of Xinjiang Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Haopeng","middleName":"","lastName":"Luan","suffix":""},{"id":97108564,"identity":"680abd63-0b7c-455a-8e00-5b9d5b64a443","order_by":1,"name":"Kai Liu","email":"","orcid":"","institution":"The First 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08:29:12","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1508247/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1508247/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":20191886,"identity":"a7088130-289c-4075-82be-a036d6eb64db","added_by":"auto","created_at":"2022-04-11 13:38:00","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":501165,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eA 54-year-old male presented with neck pain for 1 year without a history of trauma\u003c/strong\u003e a, b) Preoperative anteroposterior and lateral X-ray of cervical vertebra showed hyperosteogeny at the edge of C3-C4 vertebral body with a fracture line through intervertebral space. c) Preoperative cervical MRI showed C3-C4 intervertebral disc injury with compression of the cervical spinal cord and secondary spinal stenosis. d) Preoperative CT showed C3 vertebral instability with decreased bone mineral density. e, f) X-ray showed fracture reduction with good internal fixation position at 3 postoperative months after anterior surgery.\u0026nbsp;g, h) X-ray presented a good recovery of cervical sequence at 6 postoperative months.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-1508247/v1/7eb6b83f7cd979ba7ea8409b.png"},{"id":20191888,"identity":"81a7be9e-3612-4a0b-835c-90609c18d82b","added_by":"auto","created_at":"2022-04-11 13:38:00","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":437919,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eA 38-year-old male with neck pain caused by trauma for 2 days\u003c/strong\u003e a, b) Preoperative anteroposterior and lateral X-ray of the cervical spine showed straightening of the physiological curvature of the cervical spine (bamboo spine). c) Preoperative cervical MRI showed vertebral adnexal fracture with surrounding soft tissue injury at C6-C7. d) Preoperative CT showed intervertebral fracture with widening space. e, f) X-ray presented a satisfactory bone fusion with internal fixation at 3 postoperative months after posterior surgery. g, h) CT at 6 postoperative months showed satisfactory recovery of spinal sequence.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-1508247/v1/9e9406c57ae4095084c96f41.png"},{"id":20191887,"identity":"14949273-42fe-4fb0-93d4-e4b219d54913","added_by":"auto","created_at":"2022-04-11 13:38:00","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":430937,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eA 52-year-old male with neck pain and limitation of motion for 12 hours after falling\u003c/strong\u003e a, b) Anteroposterior and lateral X-ray of cervical vertebra showed C6-C7 vertebral body fracture with dislocation and ossification of paravertebral ligaments (bamboo spine). c) Cervical MRI showed C6-C7 intervertebral disc injury with an anterior and posterior longitudinal ligament tear. d) CT showed C6 vertebral spondylolisthesis. e, f). X-ray at 3 postoperative months after combined anterior and posterior surgery showed fracture reduction with a good internal fixation position. g, h) CT at 6 postoperative months showed a good cervical sequence and satisfactory bone fusion with internal fixation.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-1508247/v1/bd0b1776edaa50725a09faeb.png"},{"id":21770008,"identity":"10b4839d-b73f-4ff9-b235-e0467d260c26","added_by":"auto","created_at":"2022-05-23 10:59:32","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2028072,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1508247/v1/b39a548b-30e0-4952-adb4-2bcfe9bbf2de.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Management of subaxial cervical spine fracture in patients with ankylosing spondylitis: a retrospective study","fulltext":[{"header":"Background","content":"\u003cp\u003eAnkylosing spondylitis (AS) is a rheumatic spondyloarthritides, characterized by an invasion of axial skeletons such as the spine and sacroiliac joints [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Mostly, the lesion progress from the sacroiliac joint to the paraspinal ligaments, facets, and peripheral joints along the central axis of the spine. Ossification of the intervertebral discs and ligaments usually takes place in the advanced stage, which results in long-segment fusion (\u0026ldquo;bamboo\u0026rdquo; spine), and ultimately severe spinal deformity [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Because of the above pathological changes and secondary osteoporosis, spinal elasticity and compliance may be reduced by AS, which may cause spinal fractures by even slight external forces. The risk of fractures in patients with AS is 3.3 times that the normal, with an incidence of approximately 10% in AS [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe spinal fractures with AS are mostly at the lower cervical spine (approximately 80%), which are unstable cervical fractures through the three columns of the spine, and are easily associated with severe cervical spinal cord injury [\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. At present, surgical treatment for patients with AS combined with lower cervical spine fracture (SCSF) involving the three columns is recommended [\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], including anterior, posterior, and combined anterior and posterior surgery. Anterior surgery is not an appropriate option for patients with severe spinal cord compression symptoms, but posterior surgery in the treatment of anterior column vertebral collapse cannot receive stable fixation. Therefore, the surgical treatment of AS with lower cervical spine fractures is still a tremendous challenge for orthopedic surgeons.\u003c/p\u003e \u003cp\u003eIn this study, we retrospectively analyzed the clinical outcomes of patients with AS combined with SCSF treated by three approaches of surgery and explored the indications and surgical pitfalls.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eFrom January 2010 to January 2019, the medical records and imaging films were assessed retrospectively of patients with AS combined with SCSF treated by anterior, posterior, or combined anterior and posterior approach of bone grafting, and fusion using open reduction and internal fixation (ORIF). This study was conducted after receiving written informed consent from participants and approval from the Ethics Committee of our institution. Inclusion criteria are as follows: Key hallmarks of AS diagnosed by the Modified New York Criteria [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]; positive for HLA-B27 antigens; the classical appearance of a bamboo spine (squared vertebra); SCSF certified by radiographs; managed by bone grafting, and fusion using ORIF. Patients were excluded for incomplete medical records, poor compliance, comorbidities (severe heart failure, kidney or liver disease), or follow-up time less than two years.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eSurgical technique\u003c/h2\u003e \u003cp\u003eThe patient was placed in the supine position. After the general anesthesia, the junction between 2 cm of the upper edge of both ears was screwed into the screw, and the cranial traction arch was installed. The patient was placed in the prone position, and a transverse surgical incision was performed in the left anterior neck. When a combined anterior and posterior surgery performed, the cervical spine was fixed with a neck collar or neck circumference to change the surgical position as the head frame was removed. Posterior surgery was preceded using a midline incision. Simultaneously, a head frame and proper flexion were applied to expose the cervico-occipital region. When changing position, the laryngeal nerve and esophagus were easily damaged by changes in the cervical curve. The procedure must be performed carefully to avoid excessive distraction. The space between the cervical vascular sheath and the organ sheath was pulled apart, the anterior vertebral fascia was incised layer by layer. And the affected vertebral body was located by fluoroscopy. The ruptured intervertebral disc was removed, and the intervertebral disc in the upper and lower spaces of the fractured vertebral body was removed with nucleus pulposus forceps and a curette to the uncovertebral joints on both sides. The posterior longitudinal ligament was preserved, and a suitable bone spacer or allogeneic bone was placed, where the anterior column was fixed with a cervical titanium plate. Similarly, the affected posterior column was fixated by the pedicle screw when the posterior surgery was performed. After that, the internal fixator position was checked using fluoroscopy until a satisfactory position was received. The surgical area was flushed, negative pressure drainage was placed, and closed the incision.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003ePostoperative management\u003c/h2\u003e \u003cp\u003eThe drainage tube was removed when the fluid volume of the surgical area was less than 50 ml/24 hours. Patients were encouraged to wear a neck collar and walk using a walking aid to prevent pressure ulcers. After discharge, bone healing was assessed by the X-ray, and CT at 3, 6, and 12 postoperative months.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eData Collection and Outcome Evaluation\u003c/h2\u003e \u003cp\u003eThe demographic data, duration of AS, mechanism of injury, fracture type, intraoperative blood loss, operation time, bone fusion time, follow-up time, and complications were recorded. Postoperative neurological recovery of the patients was assessed by the ASIA classification.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eData were input in a Microsoft Excel spreadsheet (Redmond, WA, USA) and reported as mean and standard deviation, which were analyzed by the Mann-Whitney U test using the SPSS 20.0 software package (Chicago, IL, USA). Statistical significance was p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eBasic data of 37 patients with AS combined with SCSF were summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, with a mean follow-up time of 39.4\u0026thinsp;\u0026plusmn;\u0026thinsp;8.6 months. There were 25 cases caused by high-energy injury (vehicle accident), and 12 cases caused by falling or direct trauma. Eleven patients were managed by the anterior surgery (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), with a mean operation time and blood loss of 145.7\u0026thinsp;\u0026plusmn;\u0026thinsp;37.3 min and 354.2\u0026thinsp;\u0026plusmn;\u0026thinsp;58.2 ml respectively. The posterior surgery was performed for 13 patients (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), with a mean operation time and blood loss of 174.7\u0026thinsp;\u0026plusmn;\u0026thinsp;57.6 min and 476.6\u0026thinsp;\u0026plusmn;\u0026thinsp;108.2 ml respectively. Thirteen patients received combined anterior and posterior surgery (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), with a mean operation time and blood loss of 254.3\u0026thinsp;\u0026plusmn;\u0026thinsp;65.4 min and 697.6\u0026thinsp;\u0026plusmn;\u0026thinsp;176.3 ml respectively. No intraoperative injury of the spinal cord, nerve root, or vertebral artery occurred.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSummary of clinical data in 37 patients\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"12\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eNumber\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003cp\u003e(years)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eGender\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eDuration of AS (years)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSegment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eFracture type\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eDislocation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eApproach\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003eASIA grade\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eFollow-up\u003c/p\u003e \u003cp\u003etime\u003c/p\u003e \u003cp\u003e(months)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c12\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eBone fusion(months)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003ePreoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003ePostoperative*\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eposterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC3-C4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eanterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC4-C5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC6-C7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eposterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC3-C4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eposterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC3-C4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC4-C5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eanterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eposterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC3-C4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eanterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC4-C5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eanterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eposterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC4-C5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eanterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC6-C7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eposterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC4-C5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eposterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eposterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC4-C5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eposterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC6-C7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eanterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eanterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC6-C7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eposterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eposterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC3-C4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eanterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC6-C7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eanterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC4-C5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC4-C5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eposterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC4-C5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eanterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC5-C6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eposterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC4-C5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eanterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC6-C7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eGrade II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"12\" nameend=\"c12\" namest=\"c1\"\u003e \u003cp\u003e* \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05, Mann-Whitney U test, compared with the preoperative.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003ePreoperatively, according to the ASIA classification, there were 2 cases of grade A, 6 cases of grade B, 11 cases of grade C, 15 cases of grade D, and 3 cases of grade E. Twenty-four cases were improved to grade E (64.8%), 10 cases were improved to grade D (27%). Three patients were postoperatively assessed as grade A since severe vertebral destruction and spinal cord nerve injury. All patients were managed by bone grafting at the fracture area, with a mean bone fusion time of 8.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2 months. At the final follow-up, there was a statistical difference in ASIA grade between the preoperative and postoperative (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Postoperative complications occurred in 3 patients, including cerebrospinal fluid leakage, delayed wound healing, and pulmonary infection. And the above complications were resolved using antibiotics and a dressing change. The satisfactory bone union was obtained at the final follow-up, without internal fixator re-displacement or dislocation.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, 37 patients with AS combined with SCSF were successfully treated by the three approaches of bone grafting, fusion and ORIF. The purpose of the surgery was to decompress the compression symptoms of the spinal cord effectively, restore and stabilize the bone rupture, and promote bone union. Twenty-four cases were improved to grade E (64.8%), and 10 cases were improved to grade D (27%), according to ASIA classification. The incidence of complications was 8.1% (3/37).\u003c/p\u003e \u003cp\u003eIn the patients with AS, extensive joint and ligament ossification usually affected the axial skeleton of the spine, such as ankylosis, kyphotic deformity, and osteoporosis [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. In particular, the force line of the lower cervical may be destroyed by daily neck activities, which caused the vertebrae fracture. However, AS with SCSF is commonly misdiagnosed since the preexisting pain and kyphotic deformity [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Besides, SCSF was caused by lower energy trauma, because the vertebral osteoporosis caused by AS reduced spinal flexibility. Via published articles [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], SCSF mostly neared the cervico-thoracic junction and involved three columns of the spine, which were so unstable to associate with vertebrae dislocation, nerve compression symptoms, and respiratory complications. Westerveld et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] found that the incidence of spinal cord injury in patients with AS combined with spine fracture was significantly higher than in a patient without AS (four times). In this study, high-energy trauma was the main cause of SCSF (67.5%), which affected three-column of vertebrae in 14 cases. Besides, 34 patients were associated with neurological injury, and the longer the duration of AS, the more severe the nerve injury. Therefore, CT and MRI were recommended to be applied to diagnose AS with SCSF at the early stage, especially for patients with a history of high-energy trauma.\u003c/p\u003e \u003cp\u003eThe primary treatment of AS with SCSF was to restore the fractured ends and stabilize the spinal sagittal balance [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Nonsurgical treatment was limited to simple fractures without involving the three columns of the vertebrae and displacement, such as fixation using a Halo brace for 10 to 16 weeks [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Surgical treatment (ORIF) was necessary for patients with unstable fractures involving the three columns, spinal cord injury, vertebral disc incarceration, and the presence of sagittal or coronal imbalance [\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Its advantage was to stabilize the lower cervical sequence to promote bone union and decompress the spinal cord compression symptoms.\u003c/p\u003e \u003cp\u003eThe approach of surgery included anterior, posterior, and combined anterior and posterior. The clinical efficacy of the anterior surgery remained controversial, although its advantages of complete decompression and satisfactory bone union. Kouyoumdjian et al. [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] reported 19 patients with AS combined with SCSF were successfully treated by the anterior surgery and concluded that the lengthened internal titanium plates should be used in the anterior surgery to effectively resist abnormal stresses to receive satisfactory stabilization. However, Najib and Xiang et al. [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]considered that the anterior surgery was only suitable for SCSF with anterior and middle columns affected, whereas it had a poor ability to resist torsion and bending. In this cohort, 11 patients were performed anterior surgery and received a good bone fusion. We concluded that it was difficult to intraoperatively place the prone position in patients with kyphosis, which easily led to the iatrogenic fracture of the vertebral body and aggravated spinal cord injury. Hence, the anterior surgery could be preferred for patients with severe kyphotic deformity. If completely reducing the fracture cannot be received, an additional posterior surgery was recommended to prevent the failure of ORIF caused by the anterior stress concentration. Based on the satisfactory results of the anterior surgery in our patients, it was an effective option for patients without severe anterior column injury, disc fragmentation, and deformity.\u003c/p\u003e \u003cp\u003eThe posterior surgery had been certified its good biomechanical stability and reduction of the fracture, which was mainly suitable for fractures with the good axial load-bearing function of the anterior column, especially for fractures with dislocation and facet joint twist-lock [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Taggard et al. [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] reported 7 patients with AS combined SCSF were effectively managed by the posterior surgery, which improved the neurological compression symptoms at the final follow-up. Liang et al. [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] found that the posterior surgery using pedicle screw fixation and autologous bone grafting could play a critical role in stabilizing the spinal sagittal balance, correcting kyphosis, and relieving spinal cord compression. However, its shortcomings were mainly limited to dealing with anterior column fracture and compression, because the injured intervertebral disc was difficult to be removed [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Thirteen patients in this study were conducted by posterior surgery and obtained good outcomes of spinal sagittal balance and neurological improvement. As far as we were considered, the posterior surgery could receive stronger stability than the anterior [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], since the strong pedicle screws belonged to three-column fixation. However, its decompression of spinal cord compression caused by anterior protrusion into the spinal canal was worse than the anterior surgery. Besides, it should be in consideration that AS combined with severe osteoporosis, which was recommended that the internal fixation included 2 to 3 upper and lower vertebral bodies around the affected vertebrae respectively to resist the stress concentration caused by ankylosing segment.\u003c/p\u003e \u003cp\u003eThe combined anterior and posterior surgery was mainly indicated for patients with severe osteoporosis, three-column injury, dislocation, and spinal cord compression. Via published studies [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], satisfactory bone union with the improvement of spinal cord compression could be obtained by combined anterior and posterior surgery. For instance, Olerud and He et al. [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] presented a total of 41 patients with AS combined with SCSF successfully treated by combined anterior and posterior surgery, and considered that this method was a practical tool to treat SCSF with significant vertebral collapse and lack of anterior column support. Einsiedel et al. [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] found that there were approximately half of patients with the secondary displacement of the fracture end after anterior surgery, and they proposed that combined anterior and posterior surgery was ought to effectively decompress the spinal cord compression, especially vertebrectomy. Besides, whether anterior or posterior side surgery was performed firstly was still controversial. Some scholars believed that fractures of the anterior column mostly affected the intervertebral disc, in which there was nucleus pulposus tissue to reduce the possibility of self-fusion [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. It was necessary to perform posterior surgery firstly to provide stability to complete anterior decompression and ORIF [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Others pointed out that the order of combined surgery depended on the efficacy of skull traction [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Anterior surgery could be performed firstly as a satisfactory reduction, but posterior surgery should be performed initially in case of the failure of reduction. In our cohort, 13 patients were effectively managed by a one-stage combined anterior and posterior surgery and improved their severe neurological deficits. In our opinion, the first step should be conducted on the side with a simple type of fracture and mild neurological symptoms. The affected anterior column of 10 patients was fixated firstly using a titanium plate to provide stability for resolving the injured intervertebral disc and fracture. And posterior surgery was performed firstly on 3 patients.\u003c/p\u003e \u003cp\u003eSurgery was just the beginning and not the end of the treatment. Postoperative management and strategies for complications were equally important. In this cohort, complications occurred in 3 patients after combined anterior and posterior ORIF, including intraoperative dural tear, delayed wound healing, and pulmonary infection. Fortunately, complications were resolved using antibiotics and dressing changes. It can be concluded that the risk of intraoperative trauma and complications were brought out by the combined surgery. Hence, orthopedics should pay more attention to the surgical indication for AS combined with SCSF, and choose a practical method according to the affected vertebrae column.\u003c/p\u003e \u003cp\u003eThe limitations caused by the small-sample, single-medical-center, retrospective study existed in this study. Further, a comparison between the efficacy of different surgical approaches was not performed since the small number of cases.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eSurgical strategies for patients with AS combined with SCSF should comprehensively consider the type of injury and fracture, severe osteoporosis, spine sagittal balance, neurological compression symptoms, and deformity. Combined anterior and posterior surgery was a practical method for the treatment of patients with severe osteoporosis and neurological compression symptoms, three-column fracture combined with sagittal imbalance.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis retrospective study was approved by the Ethics Committee of the First Affiliated Hospital of Xinjiang Medical University and carried out in accordance with the ethical standards set out in the Helsinki Declaration. Informed consent was received from all participants.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data sets generated and analyzed during the current study are not publicly available due to restrictions on ethical approvals involving patient data and anonymity but can be obtained from the corresponding author on reasonable request.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was not funded by any foundation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eHPL, KL, YW, and QD developed the research questions and scope of the study. HPL, YW, and WBS conducted preoperative and postoperative data screening, and data charting. HPL drafted the manuscript, prepared tables, and figures with KL\u0026rsquo;s contribution. QD, WBS, and MM developed the literature search strategies in collaboration with the other authors. HPL, KL, YW, and WBS contributed to the organization, analysis, and interpretation of the results. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eKoller H, Koller J, Mayer M, Hempfing A, Hitzl W: \u003cb\u003eOsteotomies in ankylosing spondylitis: where, how many, and how much?\u003c/b\u003e EUR SPINE J 2018, \u003cb\u003e27\u003c/b\u003e(Suppl 1):70\u0026ndash;100.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBraun J, Sieper J: \u003cb\u003eAnkylosing spondylitis\u003c/b\u003e. LANCET 2007, \u003cb\u003e369\u003c/b\u003e(9570):1379\u0026ndash;1390.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDavey-Ranasinghe N, Deodhar A: \u003cb\u003eOsteoporosis and vertebral fractures in ankylosing spondylitis\u003c/b\u003e. 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Journal of spine surgery (Hong Kong) 2018, \u003cb\u003e4\u003c/b\u003e(3):501\u0026ndash;508.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKouyoumdjian P, Guerin P, Schaelderle C, Asencio G, Gille O: \u003cb\u003eFracture of the lower cervical spine in patients with ankylosing spondylitis\u003c/b\u003e: \u003cb\u003eRetrospective study of 19 cases\u003c/b\u003e. \u003cem\u003eOrthopaedics \u0026amp; Traumatology: Surgery \u0026amp; Research\u003c/em\u003e 2012, \u003cb\u003e98\u003c/b\u003e(5):543\u0026ndash;551.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXiang L, Yu H, Liu J, Chen Y, Yang H: \u003cb\u003eOne-stage surgery by a combined anterior-posterior approach to treat ankylosing spondylitis complicated by a multiple-level cervical vertebral chance fracture\u003c/b\u003e. 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BMC MUSCULOSKEL DIS 2021, \u003cb\u003e22\u003c/b\u003e(1).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHe A, Xie D, Cai X, Qu B, Kong Q, Xu C, Yang L, Chen X, Jia L: \u003cb\u003eOne-stage surgical treatment of cervical spine fracture-dislocation in patients with ankylosing spondylitis via the combined anterior-posterior approach\u003c/b\u003e. Medicine (Baltimore) 2017, \u003cb\u003e96\u003c/b\u003e(27):e7432.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEinsiedel T, Schmelz A, Arand M, Wilke H, Gebhard F, Hartwig E, Kramer M, Neugebauer R, Kinzl L, Schultheiss M: \u003cb\u003eInjuries of the cervical spine in patients with ankylosing spondylitis: experience at two trauma centers\u003c/b\u003e. Journal of neurosurgery. Spine 2006, \u003cb\u003e5\u003c/b\u003e(1):33.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"ankylosing spondylitis, fracture, internal fixation, subaxial cervical spine, surgery","lastPublishedDoi":"10.21203/rs.3.rs-1508247/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1508247/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003eTo assess the efficacy of anterior, posterior, and combined anterior and posterior surgery in the treatment of patients with ankylosing spondylitis (AS) combined with subaxial cervical spine fracture (SCSF).\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eFrom January 2010 to January 2019, the medical records and imaging films of patients with AS combined with SCSF treated by anterior, posterior, and combined anterior and posterior bone grafting, and fusion using open reduction and internal fixation (ORIF) were assessed retrospectively.\u003cstrong\u003e \u003c/strong\u003eThe demographic data, duration of AS, mechanism of injury, fracture type, bone fusion time, follow-up time, and complications were recorded. Postoperative neurological recovery of the patients was assessed and compared according to the ASIA classification. \u003c/p\u003e\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e A total of 37 patients with AS combined with SCSF were successfully treated by surgery, with a mean follow-up time of 39.4 ± 8.6 months. Eleven patients were managed by the anterior surgery, posterior surgery for 13 patients, and combined anterior and posterior surgery for 13 patients, with a mean bone fusion time of 8.5 ± 2.2 months. At the final follow-up, there was a statistical difference in ASIA grade between the preoperative and postoperative (\u003cem\u003eP \u003c/em\u003e\u0026lt; 0.05). Twenty-four cases were improved to grade E (64.8%), and 10 cases were improved to grade D (27%). The incidence of complications was 8.1% (3/37).\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConclusions: \u003c/strong\u003eCombined anterior and posterior surgery was a practical method for the treatment of patients with severe osteoporosis and neurological compression symptoms, three-column fracture combined with sagittal imbalance. \u0026nbsp;\u003c/p\u003e","manuscriptTitle":"Management of subaxial cervical spine fracture in patients with ankylosing spondylitis: a retrospective study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-04-11 13:37:58","doi":"10.21203/rs.3.rs-1508247/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"9b486204-d726-403d-8b85-005a0ddd10ca","owner":[],"postedDate":"April 11th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2022-05-23T10:59:23+00:00","versionOfRecord":[],"versionCreatedAt":"2022-04-11 13:37:58","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1508247","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1508247","identity":"rs-1508247","version":["v1"]},"buildId":"7rjqhiLT3MXkJMwkYKINL","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}