Faculty Bibliography

Introduction: Although three-column osteotomy (3CO; pedicle subtraction osteotomy [PSO] or vertebral column resection [VCR]) can provide powerful alignment correction and disability improvement in adult cervical deformity (ACD), these procedures are complex and associated with high complication rates. Previous reports on complications associated with 3CO for ACD have been primarily based on retrospective complication collection, which may substantially underestimate the true rates. Our objective was to provide a prospective assessment of cervical alignment improvement and complications in ACD patients treated with 3CO. Materials and Methods: Although three-column osteotomy (3CO; pedicle subtraction osteotomy [PSO] or vertebral column resection [VCR]) can provide powerful alignment correction and disability improvement in adult cervical deformity (ACD), these procedures are complex and associated with high complication rates. Previous reports on complications associated with 3CO for ACD have been primarily based on retrospective complication collection, which may substantially underestimate the true rates. Our objective was to provide a prospective assessment of cervical alignment improvement and complications in ACD patients treated with 3CO. Results: All 24 ACD patients treated with 3CO (15 PSO/ 9 VCR) achieved minimum 90-day follow-up (71% women, mean age 62 years, previous surgery in 54%). Diagnoses included: cervical sagittal imbalance (92%), cervical kyphosis (38%), proximal junctional kyphosis (17%), coronal deformity (8%) and distal junctional kyphosis (4%). The mean number of posterior fusion levels was 13, and 4% also had an anterior fusion. The most common 3CO levels were T1 (38%), T2 (29%) and T3 (21%). A total of 25 (19 major/6 minor) complications were reported, with 14 (58%) and 6 (25%) patients affected, respectively. Overall, 17 (71%) patients had at least one complication. The most common complications were excessive blood loss (>1.7L, 25%), neurologic deficit (17%), distal junctional kyphosis (DJK, 8%), wound infection (13%), and cardiorespiratory failure (8%). Four (17%) patients required re-operation within 90-days (2 for nerve root motor deficit, 1 deep wound infection, 1 implant pain/prominence). Cervical sagittal alignment improved significantly following 3CO: cervical lordosis (CL, 3degree to 13degree, P = .031), C2-7 sagittal vertical axis (66mm to 44mm, P < .001), and T1 slope minus CL (46degree to 27degree, P < .001). Conclusions: Among 24 ACD patients treated with 3CO, cervical sagittal alignment improved significantly following surgery. Overall, 17 (71%) patients had at least one complication (19 major/6 minor). The most common complications were excessive blood loss (>1.7L), neurologic deficit, DJK, wound infection, and cardiorespiratory failure. Future research focused on reducing these complications may present the greatest opportunities for safety and cost improvements for these procedures

Introduction: The length of stay (LOS) following adult spinal deformity (ASD) surgery is a critical time period allowing for recovery to levels safe enough for to return home or to rehabilitation. Thus, the goal is to minimize it for conserving hospital resources and third party payer pressure. Factors related to LOS have not been studied nor has a predictive model been created. The purpose was to create a preoperative predictive model to predict the LOS following ASD surgery. Material and Methods: Retrospective review of a multicenter, prospective ASD database. Inclusion criteria: operative pts, age >18 yrs, ASD. Pts with staged surgery at a separate hospitalization or LOS >30 days were excluded. 66 variables were initially evaluated with 40 being used for model building following univariable predictor importance >=0.90, redundancy, and collinearity testing. Variables included: demographic data, comorbidities, preop HRQOL, preop coronal and sagittal radiographic parameters, and modifiable surgical factors. A generalized linear model was constructed using a training dataset developed from a boostrapped sample with replacement using a random number generator. Pts randomly omitted from the boostrapped sample were included in the testing dataset. Accuracy was calculated by comparison of predicted LOS to the actual LOS. Results: A total of 689 patients were eligible with 653 meeting inclusion criteria. The mean LOS was 7.9 +/- 4.1 days (median = 7, range: 1-28). Following bootstrapping, a total of 893 pts were modeled, Training: 653, Testing: 240(36.6%). The linear correlations for the training and testing datasets were 0.632 and 0.507, respectively. Testing dataset accuracy within 2 days of actual LOS was 75.4% (181/240 pts). The top 10 predictors were the following in decreasing order: staged surgery (yes/ no), C7 SVA, number of posterior levels fused, Charlson Comorbidity Index, Total number of comorbidities, preop ODI score, iliac fixation (yes/no), preop SRS Activity score, preop SRS Appearance scores, and number of interbody fusion levels. Conclusion: A successful model was created to predict LOS following ASD surgery to an accuracy of 75% within 2 days. There are some factors related to LOS that are not likely captured in large databases, which may partially explain the 75% accuracy, such as rehab bed availability and social support resources

STUDY DESIGN: Retrospective cohort study of a prospectively-collected surgical database. OBJECTIVE: The aim of this study was to investigate the effect of smoking on 30-day morbidity and mortality in patients undergoing surgery for adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA: There is conflicting evidence regarding the impact of smoking on short-term outcomes after spinal fusion. METHODS: A retrospective review of the prospectively-collected American College of Surgeons National Surgical Quality Improvement database was performed for the years 2007-2013. Patients who underwent spinal fusion for ASD were identified. 30-day morbidity and mortality were compared between current smokers and nonsmokers. The independent effect of smoking was investigated via multivariate logistic regression analysis. RESULTS: A total of 1,368 patients met inclusion criteria and were included in this study. Of the 1,368 patients, 15.9% were smokers and 84.1% nonsmokers. The proportion of smokers who developed at least one complication was 9.7% versus 13.6% for nonsmokers (p = 0.119). Major complication rates (including 30-day mortality) were 6.5% for smokers and 8.4% for nonsmokers (p = 0.328). Current smoking status was not associated with increased odds of developing any complication (OR 0.90; 95% CI, 0.47-1.71; p = 0.752) or major complications (OR 1.32; 95% CI 0.64-2.70; p = 0.447) after multivariate analysis. CONCLUSION: Smoking was not associated with higher 30-day complications or mortality after corrective surgery for ASD in this study. However, given the negative effects of smoking on overall health and spine surgery outcomes in the long-term, smoking cessation prior to spinal fusion is still recommended. LEVEL OF EVIDENCE: 3.

STUDY DESIGN: Cross-sectional study of a national surgical database. OBJECTIVE: To investigate the timing of complications after adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND DATA: There is limited data on the range of days when complications after ASD surgery occur. METHODS: The American College of Surgeons National Surgical Quality Improvement database was reviewed for the years 2007-2013. Inclusion criteria were adult patients (over 21 years of age) who underwent spinal fusion for ASD. Ten unique complications occurring within 30 postoperative days were examined and the median day to diagnosis was recorded. RESULTS: A total of 1,250 patients met inclusion criteria with an overall complication rate of 13.5%. The median day of diagnosis (and interquartile range) for each complication was as follows: myocardial infarction (3.5, 1-5), pulmonary embolism (4, 2-16), reintubation (4.5, 1-11), pneumonia (6, 3-9), urinary tract infection (11, 5-15), sepsis (12, 6-18.5), deep vein thrombosis (12, 6-19), deep surgical site infection (SSI; 18.5, 13-23), superficial SSI (19, 13-24), and organ space SSI (21, 17-25). The three complications that were most commonly diagnosed before hospital discharge included pneumonia, reintubation, and myocardial infarction (diagnosed before discharge on more than 70% of cases). On the other hand, superficial, deep, and organ space infection were diagnosed in less than 40% of cases before patients left the hospital. On univariate analysis, predictors of complication occurrence included older age (p = .014), instrumentation of 7-12 levels (p = .034), and instrumentation of 13 or more levels (p = .035). CONCLUSION: Understanding the timing of specific complications after adult spinal deformity surgery is important for both patients and clinicians. Efforts in prevention of such conditions should continue, as well as heightened awareness during the periods of highest risk.

STUDY DESIGN: Retrospective cohort study OBJECTIVE.: To assess factors potentially impacting the operative approach chosen for CSM patients on a nationwide level. SUMMARY OF BACKGROUND DATA: Cervical spondylotic myelopathy (CSM) is one of the most common spinal disorders treated by spine surgeons, with operative management consisting of three approaches: anterior-only, posterior-only, or combined anterior-posterior. It is unknown whether the operative approach used differs based on patient demographics and/or insurance status. METHODS: The Nationwide Inpatient Sample from 2001-2010 was used for analysis. Admissions having a diagnosis code of 721.1 and a primary procedure code of 81.02/81.03, 81.32/81.33, 81.02/81.03 or 81.32/81.33 (combined anterior and posterior fusion/refusion at C2 or below), and 3.09 (decompression of the spinal canal including laminoplasty) were included. Analysis was adjusted for several variables including patient age, race, sex, primary payer for care, and admission source/type. RESULTS: Multivariate analyses revealed that non-Caucasian race [Black (OR = 1.39;95%CI = 1.32-1.47;p < 0.0001), Hispanic (OR = 1.51;95%CI = 1.38-1.66;p < 0.0001), Asian/Pacific Islander (OR = 1.40;95%CI = 1.15-1.70;p = 0.0007), Native American (OR = 1.33;95%CI = 1.02-1.73;p = 0.037)] and increasing age (OR = 1.03; p < 0.0001) were predictive of receiving posterior-only approaches. Female sex (OR = 1.39;95%CI = 1.34-1.43;p < 0.0001), private insurance (OR = 1.19;95%CI = 1.14-1.25;p < 0.0001), and non-trauma center admission type (OR = 1.29-1.39;95%CI = 1.16-1.56;p < 0.0001) were independently predictive of increased likelihood of receiving an anterior-only approach. Hispanic race (OR = 1.35;95%CI = 1.14-1.59;p = 0.0004) and admission source [another hospital (OR = 1.65;95%CI = 1.20-2.27;p = 0.0023), other health facility (OR = 1.68;95%CI = 1.13-2.51;p = 0.011)] were the only variables predictive of increased combined anterior-posterior approaches; Native American race (OR = 0.32;95%CI = 0.13-0.78;p = 0.013) decreased the likelihood of a combined anterior-posterior approach. CONCLUSIONS: Private insurance status, female sex, and Caucasian race independently predict receipt of anterior-only CSM approaches, while non-Caucasian race (Black, Hispanic, Asian/Pacific Islander, Native American) and non-private insurance predict receiving posterior-only CSM approaches. Given recent literature demonstrating posterior-only approaches as predictive of increased mortality in CSM (Kaye et al., 2015), our findings indicate that for CSM patients, non-Caucasian race may significantly increase mortality risk, while private insurance status may significantly decrease the risk of mortality. Further prospective study will be needed to more definitively address these issues. LEVEL OF EVIDENCE: 3.

Cervical spondylotic myelopathy (CSM) is a functional disturbance in the spinal cord as a result of degenerative changes within the cervical spinal column. This review discusses the history of CSM and its diagnosis, including clinical presentation, physical exam, and imaging studies. The pathophysiology, natural history, and treatment options are also discussed with support of the recent literature.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) performed as an outpatient has become increasingly common for treating cervical spine pathology. Few reports have attempted to assess readmissions following outpatient ACDF. This study was performed to address this issue using population-based databases. METHODS: The State Ambulatory Services Database (SASD) for New Jersey (NJ) from 2003-2012 was used for analysis. Patients receiving ACDF (defined as anterior cervical fusion (ICD-0 code=81.02) + excision of intervertebral disc (80.51)) were extracted; those with three or more levels fused (ICD-9 codes 81.63-81.64), cancer (ICD-9 codes 140-239), or trauma (ICD-9 codes=805.0-806.9) were excluded. A series of perioperative complications including durotomy, red blood cell transfusion, acute posthemorrhagic anemia, paraplegia (weakness), and mortality were examined. Propensity score matching (PSM) was used to adjust the analysis for patient age, race, sex, primary payer for care, and number of diagnoses. The NJ SASD defined readmission as admission to the same facility within seven days of initial discharge. RESULTS: Two thousand sixteen (2,016) patients were found, 1,528 of whom had readmission data. Of these 1,528 patients, 83 (5.4%) required readmission. PSM was performed prior to comparing readmission versus non-readmission. While there was no difference in perioperative complications between the two groups, the small sample size of the readmission cohort prevented this analysis from having sufficient power. No patient requiring readmission had an initial length of stay greater than one day. CONCLUSION: Based on a 10-year outpatient analysis, fewer than 6% of outpatient 1-2 level ACDFs require readmission. Future studies involving outpatients from several states will be necessary to determine whether these results of outpatient ACDF are applicable nationwide.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) is one of the most common operations utilized to address pathology of the cervical spine. Few reports have attempted to compare complications associated with inpatient versus outpatient ACDF. METHODS: The Nationwide Inpatient Sample (NIS) from 2001-2012 and the State Ambulatory Services Database (SASD) for New Jersey (NJ) from 2003-2012 were used for analysis. Patients receiving ACDF (defined as anterior cervical fusion (ICD-0 code=81.02) + excision of intervertebral disc (80.51)) were segmented into an inpatient group derived from the NIS, and an outpatient group derived from the NJ SASD. Patients receiving > 2 levels fused (ICD-9 codes 81.63-81.64), or surgery for cancer (ICD-9 codes 140-239), or trauma (ICD-9 codes=805.0-806.9) were excluded. Propensity score matching (PSM) was used to adjust the analysis for patient age, race, sex, primary payer for care, and number of medical diagnoses. RESULTS: Of the 94,492,438 inpatients comprising the NIS from 2001-2012, 257,398 received ACDF. Of the 4,194,207 outpatients comprising the NJ SASD, 2,016 received ACDF. PSM of 10,080 patients (all 2,016 SASD and 8,064 from NIS) was performed, and subsequent analysis revealed that durotomy (P=0.001;OR=0.81), paraplegia, postoperative infection, hematoma/seroma (OR=0.14), respiratory complications, acute posthemorrhagic anemia and red blood cell transfusion (all P<0.001) were less frequent in outpatient versus inpatient ACDF (p<0.05). These results were similar to an unmatched analysis involving all of the NIS patients. CONCLUSION: Accepting the limitations of the NIS and SASD (inability to distinguish between one and two-level fusions, no long-term follow-up, potential selection bias, disparities between inpatient and outpatient ACDF populations), these findings indicate that for 1-2 level ACDF, perioperative complications, including durotomy, paraplegia, hematoma, and acute posthemorrhagic anemia were more commonly reported following inpatient ACDF. Future studies involving outpatient analysis of several states will be necessary to determine whether these results of outpatient ACDF are applicable nationwide.

BACKGROUND: Diabetes as an independent driver of peri-operative outcomes, and whether its severity impacts indications is conflicted in the research. The purpose of this study is to evaluate diabetes as a predictor for postoperative outcomes in cervical spondylotic myelopathy (CSM) patients. METHODS: A retrospective review was performed of patients treated surgically for CSM (ICD-9 721.1) from 2010-2012 in the prospectively-collected American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. Outcome measures were length of stay, and the presence of complications. Diabetic patients were stratified based on whether or not their diabetes was insulin- or non-insulin-dependent. RESULTS: A total of 5,904 surgical CSM patients were included, 1101 (19%) had diabetes. 722 (65%) were non-insulin-dependent diabetics, and 381 (35%) were insulin-dependent diabetics. Diabetes was found to be an independent predictor of extended LOS (OR: 1.878[2.262-1.559], p<0.001) as well as of developing a complication (OR: 1.666[2.217-1.253], p<0.001) after controlling for associated variables like BMI. Type of diabetes (insulin- vs. non-insulin-dependent) showed little significant difference between the groups (p>0.05), however, patients with insulin-dependent diabetes were associated with an increased incidence of wound complications (p=0.027); severity of diabetes was not associated with any other individual complications. CONCLUSIONS: Type and severity of diabetes is not a predictor for complication. Diabetes is associated with extended LOS and peri-operative morbidity. Level of evidence: Class 2b. Clinical relevance: Our findings support the view of many spine surgeons, who believe that diabetes has a negative impact on the outcome of surgery for CSM. Our findings support those cohort studies that found an association between diabetes and worst post-operative outcomes following surgical treatment of CSM. These findings lend support to the importance of monitoring preoperative serum glucose levels, as prevention of peri-operative hyperglycemia has been linked to improved postoperative outcomes in spine, joint and colon surgery.

Anterior cervical discectomy and fusion (ACDF) performed as an outpatient has become increasingly common for treating cervical spine pathology, largely due to its cost savings compared with inpatient ACDF. Nearly all outpatient ACDF patient reports have originated from single-center studies, with the procedure yet to be addressed via a meta-analysis of the peer-reviewed literature. The Entrez gateway of the PubMed database was used to conduct a comprehensive literature search for articles published in English up to 3/9/16. Data from studies meeting inclusion criteria (minimum of 25 patients, control group of inpatient ACDF patients, non-duplicative data source) was then categorized and assimilated for analysis. Seven studies met inclusion criteria, encompassing a 21-year timespan. Each provided Oxford Center for Evidence-Based Medicine Level 3 evidence. The studies yielded a total of 2448 outpatient ACDF patients; only 125 (5.1%) originated from studies published prior to 2011. Single-level surgery occurred in 63.8% of patients, with 0.5% extending beyond two-level fusions. The overall complication rate was 1.8% (mean follow-up of 141.2days); only 2% of patients required readmission. In conclusion, outpatient ACDF has become increasingly popular, with more than 95% of patients represented by studies published since 2011. Nearly two-thirds of outpatient ACDFs underwent single-level fusion, with virtually none undergoing 3+ level ACDF. Outpatient ACDF is safe, with a low readmission rate and complication rates comparable to those (2-5%) associated with inpatient ACDF. These findings support an argument for increasing ACDFs performed on an outpatient basis in appropriately selected patients.