Faculty Bibliography

BACKGROUND CONTEXT: Adult spinal deformity (ASD) represents a constellation of complex mal-alignments affecting the spinal column. Corrective surgical procedures aimed at improving ASD can be equally challenging, and commonly require multiple index procedures and potential revisions prior to definitive management. There is a paucity of data comparing the outcomes of same-day (simultaneous) and two-day (staged) procedures for long spinal-fusions for ASD. Utilizing a large patient cohort with surgeon and patient-reported outcomes will be particularly useful in determining the utility and effect of staging long spine fusions for ASD. PURPOSE: Compare intra-operative, peri-operative, and two-year outcomes of staged and simultaneous procedures correcting ASD. STUDY DESIGN/SETTING: Retrospective analysis of a prospective multi-center database. PATIENT SAMPLE: 142 patients (71 Staged, 71 Simultaneous). OUTCOME MEASURES: Primary: intra- and peri-op (6 wk) complication rates. Secondary: 2 year thoracolumbar and spino-pelvic radiographic parameters, 2 year Health Related Quality of Life changes (Oswestry Disability Index and SF-36), and 2 year complication rates METHODS: Inclusion criteria included ASD patients >/=18yrs with 6-wk and 2 year follow-up. Propensity score matching identified similar patients undergoing staged (STA) or simultaneous (SIM) long spine fusions based on Surgical Invasiveness, Pelvic Tilt, and SVA. Complications, HRQLs (SRS22r, SF-36, ODI), and patient characteristics were compared across and within treatment groups at follow-up with ANOVA and paired t-tests at 3 surgical stages: intra-op, peri-op (6wk), and post-op (>6wk). RESULTS: 142 patients were included (71 STA, 71 SIM). Matching staged and simultaneous groups based on degree of deformity and surgical invasiveness created two groups similar in overall correction of the surgery. STA patients underwent more ALIF and LLIF interbody procedures while SIM patients had longer fusions. Charlson Comorbidity Index and revision status were similar between groups (p>0.05). There were significantly more complications causing reoperation in STA procedures (STA: 47% SIM: 8%, p=0.021). STA had a greater number of peri-op complications requiring a return to the OR (STA: 9.9% SIM: 1.4% p=0.029). There was no difference in intra-op complications, mortality, or peri-op infection or wound complications (p>0.05). At 2 year follow-up, incidence of revision surgery was higher in STA (STA: 21.1% SIM: 8.5%, p=0.033). CONCLUSION: Staged spinal fusions which add ALIFs and LLIFs to the procedure, compared to similar-correction simultaneous procedures, result in similar intra-operative complication incidence, but significantly higher rates of peri- and post-op complications leading to revision. Functional outcomes, radiographic parameters, and mortality were similar. This will aid surgeons in their determination of optimal treatment for such complex procedures.

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.

INTRODUCTION: Since its introduction BMP has been utilized in populations with higher rates of malunion, such as adult spinal deformity (ASD) patients. Contradictory conclusions exist in spinal literature regarding the safety and efficacy of the use of BMP in this setting. Previous studies, however, did not distinguish deformity cases from spondylolisthesis or stenosis. The purpose of this study is to evaluate the safety and efficacy of BMP use in spinal fusion surgery for ASD. METHODS: 166 papers were screened after database search. 40 full texts were assessed for eligibility. Five studies were included for meta-analysis. Three were comparative studies between a BMP and non-BMP group, and the other was used to supplement dose-effect analysis. RESULTS: The current meta-analysis found increased odds of developing radiculitis or neurological complications (OR = 2.18, 95% CI, p = 0.02, i 2 = 0), but no other significant relationship between complications commonly attributed to BMP use (tumorigenesis, infections, seroma formation, or osteolysis) and BMP use. BMP patients had decreased rates of pseudarthrosis (OR = 0.23, 95% CI, p = 0.002, i 2 = 0). There was an average dose of 8.75 mg/level in the 417 patients studied, lower than the advised dosage of 12 mg/level. CONCLUSIONS: The current literature shows BMP to be a safe and effective grafting technique in the treatment of ASD. Spine surgeons may currently be using sub-optimal doses of BMP. The benefit of increasing the rate of fusion must be weighed against the increased risk of radiculitis and neurologic complications in this patient population.

STUDY DESIGN: Retrospective study OBJECTIVE:: To propose radiographic characteristics of patients with cervical disability and to investigate the relevant parameters when assessing cervical alignment. SUMMARY OF BACKGROUND DATA: Although cervical kyphosis is traditionally recognized as presentation of cervical deformity, an increasing number of studies demonstrated that cervical kyphosis may not equal cervical deformity. Therefore, several other differentiating criteria for cervical deformity should be investigated and supported with quality of life scores. METHODS: A database of full-body radiographs was retrospectively reviewed. Patients without previous cervical surgery, with a well aligned thoracolumbar profile (defined as T1 pelvis angle (TPA) <15 degrees ) and with an available Neck Disability Index (NDI) score were reviewed in this study. Subjects were stratified into an asymptomatic (64 subjects with NDI15, VAS neck>3, or VAS arm>3). Independent t-tests were performed to investigate differences between two groups. Logistic regressions and principle component analyses were then performed. RESULTS: NDI averaged 5.43 in asymptomatic group, significantly smaller than symptomatic group (5.43 vs. 41.25). T-test revealed that C2-C7 SVA, McGregor slope (McGS) and the slope of line of sight (SLS were significantly different while C2C7 angle (Cervical curvature, CC) did not show statistical difference (P = 0.09). Logistic regressions were performed using the significantly different parameters as well as CC. Results identified C2-C7 SVA and SLS as independent risk factors for low HRQoL. The principle component analysis, lead to a new factor (0.55 x C2C7 SVA + 0.34 x C0C2 + 0.77 x CC) with strong correlations with NDI, VAS and EQ5D measurements. CONCLUSION: The traditional concept of cervical kyphosis should not be regarded as a standalone criterion of cervical deformity. The most clinically relevant components of cervical analysis are the C2-C7 SVA, C0C2 angle and C2C7 angle. In addition, the three components should be assessed in together in harmony and not individually. LEVEL OF EVIDENCE: 4.

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 review of the Nationwide Inpatient Sample from 2001 to 2010, a prospectively collected national database. OBJECTIVE: Structure an index to quantify adult spinal deformity (ASD) surgical risk based on risk factors for medical complications, surgical complications, revisions (R), mortality (M) rates, and length of hospital stay. SUMMARY OF BACKGROUND DATA: Evidence supporting ASD surgery cost-effectiveness and anticipating surgical risk is critical to evaluate the risk/benefit balance of such treatment for patients. MATERIALS AND METHODS: Discharges ages 25+, 4+ levels fused, diagnoses specific for scoliosis, and refusions. Five multivariate models determined independent risk factors that increased the risk of >/=1 for medical complications, surgical complications, R, M, and length of hospital stay. Models controlled for age, sex, race, revision status, surgical approach, levels fused, and osteotomy utilization. Odds ratios (ORs) were weighted using Nationwide Inpatient Sample weight files and based on their predictive category: 2 times for revision predictors and 4 times for mortality predictors. Predictors with OR>/=1.5 were considered clinically relevant. Fifty points were distributed among the predictors based on their accumulative OR to establish a risk index. RESULTS: A total of 10,912 ASD discharges were identified (mean age: 62 y; 73% females; 14% revision cases). The structured risk index incorporated the following factors based on accumulative ORs: pulmonary circulation disorder (42.05), drug abuse (21.86), congestive heart failure (15.25), neurological disorder (17.31), alcohol abuse (13.24), renal failure (11.64), age>65 (12.28), coagulopathy (11.65), level +9 (6.7), revision (3.35), and osteotomy (3). These risk factors were scored: 14, 7, 5, 5, 4, 4, 4, 4, 2, 1, 1, respectively. Three risk thresholds were proposed: mild (0-10), moderate (10-20), severe >20/50 points. CONCLUSIONS: This study proposes an index to quantify the possible risk of morbidity before ASD surgery that will help patients, health insurance companies, and socioeconomic studies in assessing surgical risk/benefits. LEVEL OF EVIDENCE: Level III.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: Assess outcomes of adult spinal deformity (ASD) surgery performed by 1 vs. 2 attending surgeons. SUMMARY OF BACKGROUND DATA: ASD centers have developed 2-attending teams in order to improve efficiency; their effects on complications and outcomes have not been reported. METHODS: ASD patients with >/=5 levels fused and > 2-year follow-up were included. Estimated blood loss (EBL), length of stay (LOS), operating room (OR) time, complications, quality of life (HRQOL) and X-rays were analyzed. Outcomes were compared between 1-surgeon (1S) and 2-surgeon (2S) centers. A deformity-matched cohort was analyzed. RESULTS: 188 patients in 1S and 77 in 2S group were included. 2S group patients were older and had worse deformity based on the SRS-Schwab classification (p < 0.05). There were no significant differences in levels fused (p = 0.57), LOS (8.7 vs. 8.9 days), OR time (445.9 vs. 453.2 min) or EBL (2008 vs. 1898 cc; p > 0.05). 2S patients had more 3-column osteotomies (3CO; p < 0.001) and used less bone morphogenetic protein 2 (BMP-2; 79.9 vs. 15.6%; p < 0.001). The 2S group had fewer intra-operative complications (1.3 vs. 11.1%; p = 0.006). Post-operative (6-weeks to 2-year) complications were more frequent in the 2S group (4.8 vs. 15.6%; p < 0.002). After matching for deformity, there were no differences in LOS (9.1 vs. 10.1 days), OR time (467.8 vs. 508.4 min) or EBL (3045 vs. 2247 cc; p = 0.217). 2S group used less BMP-2 (20.6 vs. 84.8%; p < 0.001), had fewer intra-operative complications (p = 0.015) but post-operative complications due to instrumentation failure/pseudarthrosis were more frequent (p < 0.01). CONCLUSIONS: No significant differences were found in LOS, OR time or EBL between the 1S and 2S groups, even when matching for severity of deformity. 2S group had less BMP-2 use, fewer intra-operative complications but more post-operative complications. LEVEL OF EVIDENCE: 2.