Currier, Bradford L.

Study Design: Multicenter retrospective case series and review of the literature. Objective: To determine the rate of esophageal perforations following anterior cervical spine surgery. Methods: As part of an AOSpine series on rare complications, a retrospective cohort study was conducted among 21 high-volume surgical centers to identify esophageal perforations following anterior cervical spine surgery. Staff at each center abstracted data from patients’ charts and created case report forms for each event identified. Case report forms were then sent to the AOSpine North America Clinical Research Network Methodological Core for data processing and analysis. Results: The records of 9591 patients who underwent anterior cervical spine surgery were reviewed. Two (0.02%) were found to have esophageal perforations following anterior cervical spine surgery. Both cases were detected and treated in the acute postoperative period. One patient was successfully treated with primary repair and debridement. One patient underwent multiple debridement attempts and expired. Conclusions: Esophageal perforation following anterior cervical spine surgery is a relatively rare occurrence. Prompt recognition and treatment of these injuries is critical to minimizing morbidity and mortality.

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.

Study Design. Prospective cohort study. Objective. To characterize the accuracy of patient recollection of preoperative symptoms after lumbar spine surgery. Summary of Background Data. Although patient-reported outcomes have become important in the evaluation of spine surgery patients, the accuracy of patient recall remains unknown. Methods. Patients undergoing lumbar decompression with or without fusion were enrolled. Back and leg Numeric Pain Scores and Oswestry Disability Indices were recorded preoperatively. Patients were asked to recall their preoperative status at a minimum of 1 year after surgery. Actual and recalled scores were compared using paired t tests and relations were quantified using Pearson correlation coefficients. Multivariable linear regression was used to identify factors that affected recollection. Results. Sixty-two patients with a mean age of 66.1 years were included. Compared to their preoperative scores, patients showed significant improvement in back pain (mean difference [MD] = −3.2, 95% CI −4.0 to −2.4), leg pain (MD −3.3, 95% CI −4.3 to −2.2), and disability (MD −25.0%, 95% CI −28.7 to −19.6). Patient recollection of preoperative status was significantly more severe than actual for back pain (MD +2.3, 95% CI 1.5–3.2), leg pain (MD +1.8, 95% CI 0.9–2.7), and disability (MD +9.6%, 95% CI 5.6–14.0). No significant correlation between actual and recalled scores with regards to back (r = 0.18) or leg (r = 0.24) pain and only moderate correlation with disability (r = 0.44) were seen. This was maintained across age, sex, and time between date of surgery and recollection. More than 40% of patients switched their predominant symptom from back pain to leg pain or leg pain to back pain on recall. Conclusion. Relying on patient recollection does not provide an accurate measure of preoperative status after lumbar spine surgery. Recall bias indicates the importance of obtaining true baseline scores and patient-reported outcomes prospectively and not retrospectively. Level of Evidence: 2

Study Design Retrospective clinical study of a prospectively collected, national database. Objective Determine the 30-day incidence, timing, and risk factors for venous thromboembolism (VTE) following thoracolumbar spine surgery. Methods The American College of Surgeons National Surgical Quality Improvement Program Participant Use File identified 43,777 patients who underwent thoracolumbar surgery from 2005 to 2012. Multiple patient characteristics were identified. The incidence and timing (in days) of deep vein thrombosis (DVT) and pulmonary embolus (PE) were determined. Multivariable regression analysis was performed to identify significant risk factors. Results Of the 43,777 patients identified as having had thoracolumbar surgery, 202 cases of PE (0.5%) and 311 cases of DVT (0.7%) were identified. VTE rates were highest in patients undergoing corpectomy, with a 1.7% PE rate and a 3.8% DVT rate. Independent risk factors for VTE included length of stay (LOS) ≥ 6 days (odds ratio [OR] 4.07), disseminated cancer (OR 1.77), white blood cell count > 12 (OR 1.76), paraplegia (OR 1.75), albumin < 3 (OR 1.73), American Society of Anesthesiologists class 4 or greater (OR 1.54), body mass index > 40 (OR 1.49), and operative time > 193 minutes (OR 1.43). LOS < 3 days was protective (OR 0.427). Conclusions We report an overall 30-day PE rate of 0.5% and DVT rate of 0.7% following thoracolumbar spine surgery. Patients undergoing corpectomy were at highest risk for VTE. Multiple VTE risk factors were identified. Further studies are needed to develop algorithms to stratify VTE risk and direct prophylaxis accordingly.

Study Design Retrospective matched cohort analysis. Objective The majority of the literature on venous thromboembolism (VTE) after spine surgery is limited to studies of thoracolumbar surgery. Less is known regarding the incidence of VTE and associated risk factors following cervical spine surgery. Methods A total of 5,405 patients at our institution underwent cervical diskectomy, laminectomy, corpectomy, laminoplasty, or fusion between 1995 and 2012; 85 of the 5,405 patients (1.57%) suffered either a DVT (55) or pulmonary embolus (51) within 30 days postoperatively. The cases were matched 1:2 to controls based on age, sex, and date of surgery. Data regarding multiple perioperative factors, demographics, and comorbidities was collected. Results Several risk factors were identified for VTE. Significant medical comorbidities included chronic venous insufficiency (odds ratio [OR] = 3.40), atrial fibrillation (OR = 2.69), obesity (OR = 2.67), and ischemic heart disease (OR = 2.18). Staged surgery (OR = 28.0), paralysis (OR = 19.0), combined approach (OR = 7.46), surgery for infection (OR = 18.5), surgery for trauma (OR = 11.1), comorbid traumatic injuries (OR > 10), oncologic procedures (OR = 5.2), use of iliac crest autograft (OR = 4.16), two or more surgical levels (OR = 3.48), blood loss > 300 mL (OR = 1.66), and length of stay 5 days or greater (OR = 3.47) were all found to be risk factors for VTE ( p < 0.05) in univariate analysis. Multivariate analysis found staged surgery (OR = 35.7), paralysis (OR = 7.86), and nonelective surgery (OR = 6.29) to be independent risk factors for VTE. Conclusions Although the incidence of VTE following cervical spine surgery is low, we identified several risk factors that may be predictive. More aggressive approaches to prophylaxis and surveillance in certain patient populations may be warranted.

Object Glial scar and cystic formation greatly contribute to the inhibition of axonal regeneration after spinal cord injury (SCI). Attempts to promote axonal regeneration are extremely challenging in this type of hostile environment. The objective of this study was to examine the surgical methods that may be used to assess the factors that influence the level of scar and cystic formation in SCI. Methods In the first part of this study, a complete transection was performed at vertebral level T9–10 in adult female Sprague-Dawley rats. The dura mater was either left open (control group) or was closed using sutures or hyaluronic acid. In the second part of the study, complete or subpial transection was performed, with the same dural closure technique applied to both groups. Histological analysis of longitudinal sections of the spinal cord was performed, and the percentage of scar and cyst formation was determined. Results Dural closure using sutures resulted in significantly less glial scar formation (p = 0.0248), while incorporation of the subpial transection surgical technique was then shown to significantly decrease cyst formation (p < 0.0001). Conclusions In this study, the authors demonstrated the importance of the vasculature in cyst formation after spinal cord trauma and confirmed the importance of dural closure in reducing glial scar formation.