Postoperative C5 Palsy after Anterior or Posterior Decompression for Degenerative Cervical Myelopathy: A Subgroup Analysis of the Multicenter, Prospective, Randomized, Phase III, CSM-Protect Clinical Trial.

STUDY DESIGN: Retrospective cohort study of prospectively accrued data. OBJECTIVE: To evaluate a large, prospective, multicentre dataset of surgically-treated DCM cases on the contemporary risk of C5 palsy with surgical approach. SUMMARY OF BACKGROUND DATA: The influence of surgical technique on postoperative C5 palsy after decompression for degenerative cervical myelopathy (DCM) is intensely debated. Comprehensive analyses are needed using contemporary data and accounting for covariates. METHODS: Patients with moderate to severe DCM were prospectively enrolled in the multicenter, randomized CSM-Protect clinical trial and underwent either anterior or posterior decompression between Jan 31, 2012, to May 16, 2017. The primary outcome was the incidence of postoperative C5 palsy, defined as onset of muscle weakness by at least one grade in manual muscle test at the C5 myotome with slight or absent sensory disruption after cervical surgery. Two comparative cohorts were made based on anterior or posterior surgical approach. Multivariate hierarchical mixed-effects logistic regression was used to estimate odds ratios (OR) with 95% confidence intervals (CI) for C5 palsy. RESULTS: A total of 283 patients were included, and 53.4% underwent posterior decompression. The total incidence of postoperative C5 palsy was 7.4% and was significantly higher in patients that underwent posterior decompression compared to anterior decompression (11.26% vs. 3.03%, P=0.008). After multivariable regression, posterior approach was independently associated with greater than four times the likelihood of postoperative C5 palsy (P=0.017). Rates of C5 palsy recovery were comparable between the two surgical approaches. CONCLUSION: The odds of postoperative C5 palsy are significantly higher after posterior decompression compared to anterior decompression for DCM. This may influence surgical decision-making when there is equipoise in deciding between anterior and posterior treatment options for DCM. LEVEL OF EVIDENCE: Therapeutic Level II.

Preoperative Heart Rate Variability Predicts Postinduction Hypotension in Patients with Cervical Myelopathy: A Prospective Observational Study.

Background: Autonomic dysfunction, commonly seen in patients with cervical myelopathy, may lead to a decrease in blood pressure intraoperatively. Objective: The aim of our study is to determine if changes in Heart rate variability (HRV) could predict hypotension after induction of anesthesia in patients with cervical myelopathy undergoing spine surgery. Methods and Material: In this prospective observational study, 47 patients with cervical myelopathy were included. Five-minute resting ECG (5 lead) was recorded preoperatively and HRV of very low frequency (VLF), low frequency (LF), and high frequency (HF) spectra were calculated using frequency domain analysis. Incidence of hypotension (MAP <80 mmHg, lasting >5 min) and the number of interventions (40 mcg of phenylephrine or 5 mg of ephedrine) required to treat the hypotension during the period from induction to surgical incision were recorded. HRV indices were compared between the hypotension group and the stable group. Results: The incidence of hypotension after induction was 74.4% (35/47) and the median (IQR) interventions needed to treat hypotension was 2 (0.5-6). Patients who experienced hypotension had lower HF power and higher LF-HF ratios. A LF/HF >2.5 indicated postinduction hypotension likely. There was a correlation between increasing LF-HF ratio and the number of interventions that needs to maintain the MAP above 80 mmHg. Conclusion: HF power was lower and LF-HF ratio was higher in patients with cervical myelopathy who developed postinduction hypotension. Hence, preoperative HRV analysis can be useful to identify patients with cervical myelopathy who are at risk of post-induction hypotension.

Spinal arachnoid cysts: A case series & systematic review of the literature.

Introduction: Spinal arachnoid cysts (SACs) are rare lesions with challenging and controversial management. Research question: We analyzed our experiences from a case series and provide a systematic review to determine 1) Demographic and clinical features of SACs, 2) Optimal imaging for diagnosis and operative planning, 3) Optimal management of SACs, and 4) Clinical outcomes following surgery. Materials and methods: A single-institution, ambispective analysis of patients with symptomatic SACs surgically managed between May 2005 and May 2019 was performed. Data were collected as per local ethics committee stipulations. A systematic review of SACs in adults was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and a preapproved protocol. Results: Our series consisted of 11 patients, M:F 8:3, mean age 47.8 years (range 18-73 years). Mean follow-up was 19 months (range 5-36 months). SACs were excised or marsupialised (7), fenestrated (3) or partially excised (1). Eight patients had expansile duroplasty, 3 primary dural closure. One patient had a cystoperitoneal shunt. All patients were AIS D preoperatively; 4 remained unchanged and 7 improved to AIS E at follow-up. Our systematic search retrieved 725 citations. Fourteen case series met the inclusion criteria. There was no evidence to support superiority of one surgical strategy over another. Surgery for symptomatic patients resulted in positive clinical outcomes. Discussion and conclusions: Symptomatic SACs require surgical intervention. Limited evidence suggests that decompressing the cord, breakdown of arachnoid adhesions, and establishing CSF flow by consideration of expansile duroplasty are important for positive outcomes.

Minimally invasive surgery for spinal cerebrospinal fluid-venous fistula ligation: patient series.

BACKGROUND: Cerebrospinal fluid-venous fistulas (CVFs) may cause cerebrospinal fluid leaks resulting in spontaneous intracranial hypotension (SIH). Surgical treatment of CVFs aims to eliminate abnormal fistulous connections between the subarachnoid space and the epidural venous plexus at the level of the nerve root sleeve. The authors propose a percutaneous minimally invasive technique for surgical ligation of CVF as an alternative to the traditional open approach using a tubular retractor system. OBSERVATIONS: Minimally invasive surgical (MIS) ligation of spinal CVF was performed in 5 patients for 6 CVFs. The definite disconnection of the CVF was achieved in all patients by clipping and additional silk tie ligation of the fistula. None of the patients experienced surgical complications or required transition to an open procedure. One patient underwent 2 MIS procedures for 2 separate CVFs. Postoperative clinical follow-up and cranial magnetic resonance imaging confirmed resolution of symptoms and radiographic SIH stigmata. LESSONS: MIS ligation of CVFs is safe and efficient. It represents an elegant and less invasive procedure, reducing the risk of wound infections and time to recovery. However, preparedness for open ligation is warranted within the same surgical setting in cases of complications and difficult accessibility.

Clinical outcomes and revision rates following four-level anterior cervical discectomy and fusion.

Studies on outcomes after four-level anterior cervical discectomy and fusion (ACDF) are limited in the literature. The purpose of this study was to report on clinical outcomes and revision rates following four-level ACDF. Patients operated with four-level ACDF were identified in a prospectively accrued single institution database. Outcome scores included the Neck Disability Index (NDI) and Visual Analogue Scale (VAS) for neck and arm pain. Reoperation rates were determined. Any complications were identified from a review of the medical records. Twenty-eight patients with a minimum of 12 months follow up were included in the analysis. The mean age at surgery was 58.5 years. The median radiographic follow up time was 23 (IQR = 16-31.25) months. Cervical lordosis was significantly improved postoperatively (- 1 to - 13, p < 0.001). At the median 24 (IQR = 17.75-39.50) months clinical follow up time, there was a significant improvement in the NDI (38 to 28, p = 0.046) and VAS for neck pain scores (5.1 to 3, p = 0.012). The most common perioperative complication was transient dysphagia (32%) followed by hoarseness (14%). Four (14%) patients required revision surgery at a median 11.5 (IQR = 2-51) months postoperatively. The results of this study indicate that patients who undergo four-level ACDF have a significant improvement in clinical outcomes at median 24 months follow up. Stand-alone four-level ACDF is a valid option for the management of complex cervical degenerative conditions.

Recent advances and new discoveries in the pipeline of the treatment of primary spinal tumors and spinal metastases: a scoping review of registered clinical studies from 2000 to 2020.

The field of spinal oncology has substantially evolved over the past decades. This review synthesizes and appraises what was learned and what will potentially be discovered from the recently completed and ongoing clinical studies related to the treatment of primary and secondary spinal neoplasms. This scoping review included all clinical studies on the treatment of spinal neoplasms registered in the ClinicalTrials.gov website from February 2000 to December 2020. The terms "spinal cord tumor," "spinal metastasis," and "metastatic spinal cord compression" were used. Of the 174 registered clinical studies on primary spinal tumors and spinal metastasis, most of the clinical studies registered in this American registry were interventional studies led by single institutions in North America (n = 101), Europe (n = 43), Asia (n = 24), or other continents (n = 6). The registered clinical studies mainly focused on treatment strategies for spinal neoplasms (90.2%) that included investigating stereotactic radiosurgery (n = 33), radiotherapy (n = 21), chemotherapy (n = 20), and surgical technique (n = 11). Of the 69 completed studies, the results from 44 studies were published in the literature. In conclusion, this review highlights the key features of the 174 clinical studies on spinal neoplasms that were registered from 2000 to 2020. Clinical trials were heavily skewed toward the metastatic population as opposed to the primary tumors which likely reflects the rarity of the latter condition and associated challenges in undertaking prospective clinical studies in this population. This review serves to emphasize the need for a focused approach to enhancing translational research in spinal neoplasms with a particular emphasis on primary tumors.

Clinical outcomes of nonoperatively managed degenerative cervical myelopathy: an ambispective longitudinal cohort study in 117 patients.

OBJECTIVE: Degenerative cervical myelopathy (DCM) is among the most common pathologies affecting the spinal cord but its natural history is poorly characterized. The purpose of this study was to investigate functional outcomes in patients with DCM who were managed nonoperatively as well as the utility of quantitative clinical measures and MRI to detect deterioration. METHODS: Patients with newly diagnosed DCM or recurrent myelopathic symptoms after previous surgery who were initially managed nonoperatively were included. Retrospective chart reviews were performed to analyze clinical outcomes and anatomical MRI scans for worsening compression or increased signal change. Quantitative neurological assessments were collected prospectively, including modified Japanese Orthopaedic Association (mJOA) score; Quick-DASH; graded redefined assessment of strength, sensation, and prehension-myelopathy version (GRASSP-M: motor, sensory, and dexterity); grip dynamometer; Berg balance scale score; gait stability ratio; and gait variability index. A deterioration of 10% was considered significant (e.g., a 2-point decrease in mJOA score). RESULTS: A total of 117 patients were included (95 newly diagnosed, 22 recurrent myelopathy), including 74 mild, 28 moderate, and 15 severe cases. Over a mean follow-up of 2.5 years, 57% (95% CI 46%-67%) of newly diagnosed patients and 73% (95% CI 50%-88%) of patients with recurrent DCM deteriorated neurologically. Deterioration was best detected with grip strength (60%), GRASSP dexterity (60%), and gait stability ratio (50%), whereas the mJOA score had low sensitivity (33%) in 50 patients. A composite score had a sensitivity of 81% and a specificity of 82%. The sensitivity of anatomical MRI was 28% (83 patients). CONCLUSIONS: DCM appears to have a poor natural history; however, prospective studies are needed for validation. Serial assessments should include mJOA score, grip strength, dexterity, balance, and gait analysis. The absence of worsening on anatomical MRI or in mJOA scores is not sufficient to determine clinical stability.

Long-level intramedullary spinal cord astrocytoma complicated with spine scoliosis: Report of two cases.

INTRODUCTION AND IMPORTANCE: Long-level intramedullary astrocytomas complicated with spine scoliosis are rare. Surgical treatment of such tumors becomes more complicated and challenging when spinal scoliosis is present. However, studies describing the treatment of long segmental intramedullary spinal cord astrocytomas complicated with severe spine scoliosis have been rarely reported. CASE PRESENTATION: Two cases of long-level intramedullary astrocytomas complicated with severe spine scoliosis were surgically treated with one-stage operation of tumor resection and scoliosis correction in this report. Case 1: A 16-year-old boy presented to our hospital with a five-month progressive paresthesia, weakness of the left lower limb, and a long-time abnormal body appearance. MRI showed a T4-T12 intramedullary tumor combined with spinal scoliosis. Case 2: A 14-year-old boy presented at our service with a 6-year history of visible spine scoliosis and a 1-year progressive motor disability of bilateral lower limbs. Spine MRI indicated a long-level abnormal syringomyelia signal from C4 to L1 and there was irregular enhancement after intravenous contrast medium administration at C7-T2 and T9-T12 level. DISCUSSION: We performed a laminectomy over the whole length of the tumor and corrected the scoliosis with trans-pedicle screws. The patients exhibited a long-time tumor free with largely neurological function preservation. One-stage operation did not generate severe short- or long-term complications. The correction of the scoliosis prevented the progression of the spinal deformity and facilitated the recovery of normal life. CONCLUSION: This case report demonstrates that the one-stage resection of long-level intramedullary astrocytoma and correction of the complicated scoliosis might be a feasible option.

Inter-rater Reliability of the Modified Japanese Orthopedic Association Score in Degenerative Cervical Myelopathy: A Cross-sectional Study.

STUDY DESIGN: Prospective cross-sectional blinded-assessor cohort study. OBJECTIVE: The aim of this study was to determine the inter-rater reliability of the modified Japanese Orthopaedic Association (mJOA) score in a large cohort of degenerative cervical myelopathy (DCM) patients. SUMMARY OF BACKGROUND DATA: The mJOA score is widely accepted as the primary outcome measure in DCM; it has been utilized in clinical practice guidelines and directly influences treatment recommendations, but its reliability has not been established. METHODS: A refined version of the mJOA was administered to DCM patients by two or more blinded clinicians. Inter-rater reliability was measured using intraclass correlation coefficient (ICC), agreement, and mean difference for mJOA total score and subscores. Data were also analyzed with analysis of variance for differences by mJOA severity (mild: 15-17, moderate: 12-14, severe: <12), assessor, assessment order, previous surgery, age, and sex. RESULTS: One hundred fifty-four DCM patients underwent 322 mJOA assessments (183 paired assessments). ICC was 0.88 for total mJOA, 0.79 for upper extremity (UE) motor, 0.84 for lower extremity (LE) motor, 0.63 for UE sensation, and 0.78 for urinary function subscores. Paired assessments were identical across all four subscores in 25%. The mean difference in mJOA was 0.93 points between assessors, and this differed by severity (mild: 0.68, moderate: 1.24, severe: 0.87, P = 0.001). Differences of ≥ 2 points occurred in 19%. Disagreement between mild and moderate severity occurred in 12% of patients. Other variables did not demonstrate significant relationships with mJOA scores. CONCLUSION: The inter-rater reliability of total mJOA and its subscores is good, except for UE sensory function (moderate). However, the vast majority of assessments differed between observers, indicating that this measure should be interpreted carefully, particularly when near the threshold between severity categories, or when a patient is reassessed for deterioration. Further efforts to educate clinicians on administration and to refine the UE sensory subscore may enhance the reliability of this tool.Level of Evidence: 1.

Safety and efficacy of riluzole in patients undergoing decompressive surgery for degenerative cervical myelopathy (CSM-Protect): a multicentre, double-blind, placebo-controlled, randomised, phase 3 trial.

BACKGROUND: Degenerative cervical myelopathy represents the most common form of non-traumatic spinal cord injury. This trial investigated whether riluzole enhances outcomes in patients undergoing decompression surgery for degenerative cervical myelopathy. METHODS: This multicentre, double-blind, placebo-controlled, randomised, phase 3 trial was done at 16 university-affiliated centres in Canada and the USA. Patients with moderate-to-severe degenerative cervical myelopathy aged 18-80 years, who had a modified Japanese Orthopaedic Association (mJOA) score of 8-14, were eligible. Patients were randomly assigned (1:1) to receive either oral riluzole (50 mg twice a day for 14 days before surgery and then for 28 days after surgery) or placebo. Randomisation was done using permuted blocks stratified by study site. Patients, physicians, and outcome assessors remained masked to treatment group allocation. The primary endpoint was change in mJOA score from baseline to 6 months in the intention-to-treat (ITT) population, defined as all individuals who underwent randomisation and surgical decompression. Adverse events were analysed in the modified intention-to-treat (mITT) population, defined as all patients who underwent randomisation, including those who did not ultimately undergo surgical decompression. This study is registered with ClinicalTrials.gov, NCT01257828. FINDINGS: From Jan 31, 2012, to May 16, 2017, 408 patients were screened. Of those screened, 300 were eligible (mITT population); 290 patients underwent decompression surgery (ITT population) and received either riluzole (n=141) or placebo (n=149). There was no difference between the riluzole and placebo groups in the primary endpoint of change in mJOA score at 6-month follow-up: 2·45 points (95% CI 2·08 to 2·82 points) versus 2·83 points (2·47 to 3·19), difference -0·38 points (-0·90 to 0·13; p=0·14). The most common adverse events were neck or arm or shoulder pain, arm paraesthesia, dysphagia, and worsening of myelopathy. There were 43 serious adverse events in 33 (22%) of 147 patients in the riluzole group and 34 serious adverse events in 29 (19%) of 153 patients in the placebo group. The most frequent severe adverse events were osteoarthrosis of non-spinal joints, worsening of myelopathy, and wound complications. INTERPRETATION: In this trial, adjuvant treatment for 6 weeks perioperatively with riluzole did not improve functional recovery beyond decompressive surgery in patients with moderate-to-severe degenerative cervical myelopathy. Whether riluzole has other benefits in this patient population merits further study. FUNDING: AOSpine North America.

The discrepancy between functional outcome and self-reported health status after surgery for degenerative cervical myelopathy.

INTRODUCTION: Surgery for degenerative cervical myelopathy has shown not only to halt neurologic deterioration, but also to improve functional impairments. Despite these improvements, some patients may be dissatisfied with their outcomes. This study aims to (1) investigate discrepancies between postoperative clinical measures and self-reported health status, and (2) identify important predictors of such discrepancies. METHODS: Four hundred and seventy-nine surgical patients were prospectively enrolled in the CSM-International study at 16 global sites. At 1-year post-op, patients rated their general health status compared with their immediate preoperative status (much better, somewhat better, the same, somewhat worse, much worse). Descriptive analyses were conducted to evaluate the agreement between achieving a clinically important improvement (MCID) in function (modified Japanese Orthopedic Association [mJOA] scale) and self-reported health status. Agreement was defined as achieving the MCID on the mJOA and reporting general health as somewhat better or much better, whereas disagreement was defined as achieving MCID on the mJOA and reporting general health as the same, somewhat worse or much worse. Logistic regression analysis was used to determine factors that influence agreement between self-report of health status and functional outcomes. RESULTS: A total of 395 patients had complete follow-up data at 1-year and were included in this analysis. Based on patient self-reports, 56 (14.2%) were somewhat or much worse than a year ago, 80 (20.2%) patients were the same and 259 (65.6%) patients were somewhat or much better. Thirty percent of patients who reported being somewhat or much worse were found to achieve the MCID on the mJOA; 57.5% of patients who indicated their health status were the same as before surgery also exhibited clinically meaningful improvements in functional impairment. Based on multivariate analysis, there was an increased odds of observing an agreement between self-reports of health status and functional outcomes if the patient exhibited greater improvement in mJOA upper extremity motor function at 1-year (odds ratio [OR]: 1.41, 95% confidence interval [CI] 1.03-1.93, p=.033) and reduced odds of agreement with increased age (OR for every decade: 0.66, 95% CI 0.50-0.87, p=.0035) and increased bodily pain at 1-year (OR: 0.62, 95% CI 0.49-078, p<.0001). CONCLUSIONS: There was a discrepancy between changes in mJOA and self-reports of health status in patients undergoing surgery for degenerative cervical myelopathy. Increased bodily pain at 1-year, smaller improvements in postoperative upper extremity score and increased age were associated with worsened or unchanged general health status, despite clinically significant improvements in overall postoperative function.

Monitoring for myelopathic progression with multiparametric quantitative MRI.

BACKGROUND: Patients with mild degenerative cervical myelopathy (DCM) are often managed non-operatively, and surgery is recommended if neurological progression occurs. However, detection of progression is often subjective. Quantitative MRI (qMRI) directly measures spinal cord (SC) tissue changes, detecting axonal injury, demyelination, and atrophy. This longitudinal study compared multiparametric qMRI with clinical measures of progression in non-operative DCM patients. METHODS: 26 DCM patients were followed. Clinical data included modified Japanese Orthopedic Association (mJOA) and additional assessments. 3T qMRI data included cross sectional area, diffusion fractional anisotropy, magnetization transfer ratio, and T2*-weighted white/grey matter signal ratio, extracted from the compressed SC and above/below. Progression was defined as 1) patients' subjective impression, 2) 2-point mJOA decrease, 3) ≥3 clinical measures worsening ≥5%, 4) increased compression on MRI, or 5) ≥1 of 10 qMRI measures or composite score worsening (p < 0.004, corrected). RESULTS: Follow-up (13.5 ± 4.9 months) included mJOA in all 26 patients, MRI in 25, and clinical/qMRI in 22. 42.3% reported subjective worsening, compared with mJOA (11.5%), MRI (20%), comprehensive assessments (54.6%), and qMRI (68.2%). Relative to subjective worsening, qMRI showed 100% sensitivity and 53.3% specificity compared with comprehensive assessments (75%, 60%), mJOA (27.3%, 100%), and MRI (18.2%, 81.3%). A decision-making algorithm incorporating qMRI identified progression and recommended surgery for 11 subjects (42.3%). CONCLUSIONS: Quantitative MRI shows high sensitivity to detect myelopathic progression. Our results suggest that neuroplasticity and behavioural adaptation may mask progressive SC tissue injury. qMRI appears to be a useful method to confirm subtle myelopathic progression in individual patients, representing an advance toward clinical translation of qMRI.

Rare Complications of Cervical Spine Surgery: Pseudomeningocoele.

STUDY DESIGN: This study was a retrospective, multicenter cohort study. OBJECTIVES: Rare complications of cervical spine surgery are inherently difficult to investigate. Pseudomeningocoele (PMC), an abnormal collection of cerebrospinal fluid that communicates with the subarachnoid space, is one such complication. In order to evaluate and better understand the incidence, presentation, treatment, and outcome of PMC following cervical spine surgery, we conducted a multicenter study to pool our collective experience. METHODS: This study was a retrospective, multicenter cohort study of patients who underwent cervical spine surgery at any level(s) from C2 to C7, inclusive; were over 18 years of age; and experienced a postoperative PMC. RESULTS: Thirteen patients (0.08%) developed a postoperative PMC, 6 (46.2%) of whom were female. They had an average age of 48.2 years and stayed in hospital a mean of 11.2 days. Three patients were current smokers, 3 previous smokers, 5 had never smoked, and 2 had unknown smoking status. The majority, 10 (76.9%), were associated with posterior surgery, whereas 3 (23.1%) occurred after an anterior procedure. Myelopathy was the most common indication for operations that were complicated by PMC (46%). Seven patients (53%) required a surgical procedure to address the PMC, whereas the remaining 6 were treated conservatively. All PMCs ultimately resolved or were successfully treated with no residual effects. CONCLUSIONS: PMC is a rare complication of cervical surgery with an incidence of less than 0.1%. They prolong hospital stay. PMCs occurred more frequently in association with posterior approaches. Approximately half of PMCs required surgery and all ultimately resolved without residual neurologic or other long-term effects.

Epidemiology and Outcomes of Vertebral Artery Injury in 16 582 Cervical Spine Surgery Patients: An AOSpine North America Multicenter Study.

STUDY DESIGN: A multicenter retrospective case series was compiled involving 21 medical institutions. Inclusion criteria included patients who underwent cervical spine surgery between 2005 and 2011 and who sustained a vertebral artery injury (VAI). OBJECTIVE: To report the frequency, risk factors, outcomes, and management goals of VAI in patients who have undergone cervical spine surgery. METHODS: Patients were evaluated on the basis of condition-specific functional status using the Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA) score, the Nurick scale, and the 36-Item Short-Form Health Survey (SF-36). RESULTS: VAIs were identified in a total of 14 of 16 582 patients screened (8.4 per 10 000). The mean age of patients with VAI was 59 years (±10) with a female predominance (78.6%). Patient diagnoses included myelopathy, radiculopathy, cervical instability, and metastatic disease. VAI was associated with substantial blood loss (770 mL), although only 3 cases required transfusion. Of the 14 cases, 7 occurred with an anterior-only approach, 3 cases with posterior-only approach, and 4 during circumferential approach. Fifty percent of cases of VAI with available preoperative imaging revealed anomalous vessel anatomy during postoperative review. Average length of hospital stay was 10 days (±8). Notably, 13 of the 14 (92.86%) cases resolved without residual deficits. Compared to preoperative baseline NDI, Nurick, mJOA, and SF-36 scores for these patients, there were no observed changes after surgery (P = .20-.94). CONCLUSIONS: Vertebral artery injuries are potentially catastrophic complications that can be sustained from anterior or posterior cervical spine approaches. The data from this study suggest that with proper steps to ensure hemostasis, patients recover function at a high rate and do not exhibit residual deficits.

Incidence and Outcomes of Acute Implant Extrusion Following Anterior Cervical Spine Surgery.

STUDY DESIGN: Multi-institutional retrospective case series of 8887 patients who underwent anterior cervical spine surgery. OBJECTIVE: Anterior decompression from discectomy or corpectomy is not without risk. Surgical morbidity ranges from 9% to 20% and is likely underreported. Little is known of the incidence and effects of rare complications on functional outcomes following anterior spinal surgery. In this retrospective review, we examined implant extrusions (IEs) following anterior cervical fusion. METHODS: A retrospective multicenter case series study involving 21 high-volume surgical centers from the AOSpine North America Clinical Research Network. Medical records for 17 625 patients who received cervical spine surgery (levels from C2 to C7) between January 1, 2005, and December 31, 2011, were reviewed to identify occurrence of 21 predefined treatment complications. RESULTS: Following anterior cervical fusion, the incidence of IE ranged from 0.0% to 0.8% across 21 institutions with 11 cases reported. All surgeries involved multiple levels, and 7/11 (64%) involved either multilevel corpectomies or hybrid constructs with at least one adjacent discectomy to a corpectomy. In 7/11 (64%) patients, constructs ended with reconstruction or stabilization at C7. Nine patients required surgery for repair and stabilization following IE. Average length of hospital stay after IE was 5.2 days. Only 2 (18%) had residual deficits after reoperation. CONCLUSIONS: IE is a very rare complication after anterior cervical spine surgery often requiring revision. Constructs requiring multilevel reconstruction, especially at the cervicothoracic junction, have a higher risk for failure, and surgeons should proceed with caution in using an anterior-only approach in these demanding cases. Surgeons can expect most patients to regain function after reoperation.

Misplaced Cervical Screws Requiring Reoperation.

STUDY DESIGN: A multicenter, retrospective case series. OBJECTIVE: In the past several years, screw fixation of the cervical spine has become commonplace. For the most part, this is a safe, low-risk procedure. While rare, screw backout or misplaced screws can lead to morbidity and increased costs. We report our experiences with this uncommon complication. METHODS: A multicenter, retrospective case series was undertaken at 23 institutions in the United States. Patients were included who underwent cervical spine surgery from January 1, 2005, to December 31, 2011, and had misplacement of screws requiring reoperation. Institutional review board approval was obtained at all participating institutions, and detailed records were sent to a central data center. RESULTS: A total of 12 903 patients met the inclusion criteria and were analyzed. There were 11 instances of screw backout requiring reoperation, for an incidence of 0.085%. There were 7 posterior procedures. Importantly, there were no changes in the health-related quality-of-life metrics due to this complication. There were no new neurologic deficits; a patient most often presented with pain, and misplacement was diagnosed on plain X-ray or computed tomography scan. The most common location for screw backout was C6 (36%). CONCLUSIONS: This study represents the largest series to tabulate the incidence of misplacement of screws following cervical spine surgery, which led to revision procedures. The data suggest this is a rare event, despite the widespread use of cervical fixation. Patients suffering this complication can require revision, but do not usually suffer neurologic sequelae. These patients have increased cost of care. Meticulous technique and thorough knowledge of the relevant anatomy are the best means of preventing this complication.

A Multicenter Study of the Presentation, Treatment, and Outcomes of Cervical Dural Tears.

STUDY DESIGN: Retrospective multicenter case series study. OBJECTIVE: Because cervical dural tears are rare, most surgeons have limited experience with this complication. A multicenter study was performed to better understand the presentation, treatment, and outcomes following cervical dural tears. METHODS: Multiple surgeons from 23 institutions retrospectively identified 21 rare complications that occurred between 2005 and 2011, including unintentional cervical dural tears. Demographic data and surgical history were obtained. Clinical outcomes following surgery were assessed, and any reoperations were recorded. Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA), Nurick classification (NuC), and Short-Form 36 (SF36) scores were recorded at baseline and final follow-up at certain centers. All data were collected, collated, and analyzed by a private research organization. RESULTS: There were 109 cases of cervical dural tears among 18 463 surgeries performed. In 101 cases (93%) there was no clinical sequelae following successful dural tear repair. There were statistical improvements (P < .05) in mJOA and NuC scores, but not NDI or SF36 scores. No specific baseline or operative factors were found to be associated with the occurrence of dural tears. In most cases, no further postoperative treatments of the dural tear were required, while there were 13 patients (12%) that required subsequent treatment of cerebrospinal fluid drainage. Analysis of those requiring further treatments did not identify an optimum treatment strategy for cervical dural tears. CONCLUSIONS: In this multicenter study, we report our findings on the largest reported series (n = 109) of cervical dural tears. In a vast majority of cases, no subsequent interventions were required and no clinical sequelae were observed.

C5 Palsy After Cervical Spine Surgery: A Multicenter Retrospective Review of 59 Cases.

STUDY DESIGN: A multicenter, retrospective review of C5 palsy after cervical spine surgery. OBJECTIVE: Postoperative C5 palsy is a known complication of cervical decompressive spinal surgery. The goal of this study was to review the incidence, patient characteristics, and outcome of C5 palsy in patients undergoing cervical spine surgery. METHODS: We conducted a multicenter, retrospective review of 13 946 patients across 21 centers who received cervical spine surgery (levels C2 to C7) between January 1, 2005, and December 31, 2011, inclusive. P values were calculated using 2-sample t test for continuous variables and χ2 tests or Fisher exact tests for categorical variables. RESULTS: Of the 13 946 cases reviewed, 59 patients experienced a postoperative C5 palsy. The incidence rate across the 21 sites ranged from 0% to 2.5%. At most recent follow-up, 32 patients reported complete resolution of symptoms (54.2%), 15 had symptoms resolve with residual effects (25.4%), 10 patients did not recover (17.0%), and 2 were lost to follow-up (3.4%). CONCLUSION: C5 palsy occurred in all surgical approaches and across a variety of diagnoses. The majority of patients had full recovery or recovery with residual effects. This study represents the largest series of North American patients reviewed to date.

Prevalence and Outcomes in Patients Undergoing Reintubation After Anterior Cervical Spine Surgery: Results From the AOSpine North America Multicenter Study on 8887 Patients.

STUDY DESIGN: A multicenter, retrospective cohort study. OBJECTIVE: To evaluate clinical outcomes in patients with reintubation after anterior cervical spine surgery. METHODS: A total of 8887 patients undergoing anterior cervical spine surgery were enrolled in the AOSpine North America Rare Complications of Cervical Spine Surgery study. Patients with or without complications after surgery were included. Demographic and surgical information were collected for patients with reintubation. Patients were evaluated using a variety of assessment tools, including the modified Japanese Orthopedic Association scale, Nurick score, Neck Disability Index, and Short Form-36 Health Survey. RESULTS: Nine cases of postoperative reintubation were identified. The total prevalence of this complication was 0.10% and ranged from 0% to 0.59% across participating institutions. The time to development of airway symptoms after surgery was within 24 hours in 6 patients and between 5 and 7 days in 3 patients. Although 8 patients recovered, 1 patient died. At final follow-up, patients with reintubation did not exhibit significant and meaningful improvements in pain, functional status, or quality of life. CONCLUSIONS: Although the prevalence of reintubation was very low, this complication was associated with adverse clinical outcomes. Clinicians should identify their high-risk patients and carefully observe them for up to 2 weeks after surgery.

Airway adverse events following posterior occipito-cervical spinal fusion.

Management of the airway may be challenging in patients undergoing occipito-cervical spine fusions (OCF). Changes in the occipito-cervical angle (dOC2A) of fusion after surgery may result in acute airway obstruction, dyspnea and/or dysphagia. Objectives of the study were to review the airway management of patients during posterior OCF, determine the incidence, nature and risk factors for postoperative airway adverse events (AEs), and to determine the relationship between airway AEs and the change in dOC2A. In this retrospective cohort of 59 patients, following extubation in the operating room (OR), there were no complications in 43 (73%) patients (Group 1). Sixteen (27%) patients (Group 2) had airway complications; 4 requiring reintubation and 12 having delayed extubation. The number of vertebral levels fused (>6), presence of difficult intubation and duration of surgery (>5h) were significantly associated with AEs. There was no significant difference in the dOC2A between the groups (-1.070±5.527 versus -4.375±10.788, p=0.127). Airway management in patients undergoing OCF poses a challenge for the anesthesiology and surgical teams. The incidence of AEs was 27%. The decision to extubate immediately after surgery needs to be individualized. Factors such as difficult intubation, number of vertebral levels fused and duration of surgery have to be considered. A significant correlation between dOC2A and postoperative AEs could not be established. Risk factors for postoperative AEs are multifactorial and prospective evaluation of these factors is indicated.