Faculty Bibliography

BACKGROUND CONTEXT: Blood transfusions in spine surgery are shown to be associated with increased patient morbidity. The association between transfusion performed using a liberal hemoglobin trigger-defined as an intraoperative hemoglobin level of >/=10 g/dL, a postoperative level of >/=8 g/dL, or a whole hospital nadir between 8-10 g/dL-and perioperative morbidity and cost in spine surgery patients is unknown and thus was investigated in this study. PURPOSE: To describe the perioperative outcomes and economic cost associated with liberal hemoglobin trigger transfusion among spine surgery patients. STUDY DESIGN/SETTING: Retrospective study. PATIENT SAMPLE: The surgical billing database at our institution was queried for inpatients discharged between 2008 and 2015 after the following procedures: atlantoaxial fusion, anterior cervical fusion, posterior cervical fusion, anterior lumbar fusion, posterior lumbar fusion, lateral lumbar fusion, other procedures, and tumor-related surgeries. In total, 6931 patients were included for analysis. OUTCOME MEASURES: The primary outcome was composite morbidity which was comprised of: (1) infection (sepsis, surgical-site infection, Clostridium dificile, or drug-resistant infection), (2) thrombotic event (pulmonary embolus, deep venous thrombosis, or disseminated intravascular coagulation), (3) kidney injury, (4) respiratory event, and/or (5) ischemic event (transient ischemic attack, myocardial infarction, or cerebrovascular accident). METHODS: Data on intraoperative transfusion were obtained from an automated prospectively collected anesthesia data management system. Data on postoperative hospital transfusion was obtained through a Web-based intelligence portal. Based on previous research, we analyzed the data using three definitions of a liberal transfusion trigger in patients who received an RBC transfusion: a liberal intraoperative Hb trigger as a nadir Hb level of 10 g/dL or greater, a liberal postoperative Hb trigger as a nadir Hb level of 8 g/dL or greater, or a whole hospital nadir Hb level of 8-10 g/dL. Variables analyzed included in-hospital morbidity, mortality, length of stay, and total costs associated with a liberal transfusion strategy. RESULTS: Among patients with a whole hospital stay nadir hemoglobin between 8 to 10 g/dL, transfused patients demonstrated a longer in-hospital stay (median [IQR], 6 [5-9] vs. 4 [3-6] days; P<0.0001) and a higher perioperative morbidity (n=145, [11.5%] vs. n=74, [6.1%]; P<0.0001) than those not transfused. Even after adjusting for age, gender, race, ASA class, CCI score, estimated blood loss, baseline hemoglobin value, number of operated levels, and surgery type, logistic regression analysis revealed that patients with a nadir hemoglobin of 8-10 g/dL who were transfused had an independently higher risk of perioperative morbidity (odds ratio [OR] = 2.12; 95% confidence interval [CI], 1.24-3.64; P=0.006). Estimated additional costs associated with liberal trigger use, defined as a transfusion occurring in patients with a whole hospital stay nadir Hb of 8-10 g/dL, ranged from $202,675 to $700,151 annually. CONCLUSIONS: Transfusion using a liberal trigger is associated with increased morbidity, even after controlling for possible confounders. Our results suggest that modification of transfusion practice may be a potential area for improving patient outcomes and reducing costs.

STUDY DESIGN:Retrospective review of a prospective database. OBJECTIVES:To investigate adult spinal deformity (ASD) surgery outcome trends on a nationwide scale using the Nationwide Inpatient Sample (NIS) from 2003 to 2010. METHODS:ASD patients ≥25 years from 2003 to 2010 in the NIS undergoing anterior, posterior, or combined surgical approaches were included. Fractures, 9+ levels fused, or any cancer were excluded. Patient demographics, hospital data, and procedure-related complications were evaluated. Yearly trends were analyzed using univariate analysis and linear regression modeling. RESULTS:Of 10,966 discharges, 1,952 were anterior, 6,524 were posterior, and 1,106 were combined. The total surgical ASD volume increased by 112.5% (p = .029), and both the average patient age (p < .001) and number of patients >65 years old significantly increased from 2003 to 2010 (p = .009). Anterior approach case volume decreased by 13.7% (p = .019), whereas that of combined increased by 22.7% (p = .047). Posterior case volume increased by 38.9% from 2003 to 2010, though insignificantly (p = .084). Total hospital charges for all approaches increased over the interval (p < .001). Total length of stay for all approaches decreased over the time interval (p < .005). Although the overall morbidity for all approaches increased by 22.7% (p < .001), mortality did not change (p = .817). The most common morbidities in 2003 were hemorrhagic anemia, accidental cut, puncture, perforation, or laceration during a procedure, and device-related complications, which persisted in 2010 with the exception of increased acute respiratory distress syndrome and pulmonary-related complications. CONCLUSIONS:For ASD surgery from 2003 to 2010, the volume of anterior approaches decreased, whereas posterior procedures did not change, and combined approaches increased. Total hospital charges increased for all considered procedures, length of hospital stay decreased, whereas operative patients were increasingly elderly, and more procedures were observed for patients >65 years old. For all approaches, morbidity increased whereas mortality did not change. Future study is required to develop methods to reduce morbidity and costs, thereby optimizing patient outcomes.

STUDY DESIGN: A retrospective review of a prospectively collected database, the Nationwide Inpatient Sample (NIS), years 2003 to 2012. OBJECTIVES: The aim of this study was to examine trends in the management of scoliosis in elderly (age >75 yrs) patients from 2003 to 2012. SUMMARY OF BACKGROUND DATA: Scoliosis incidence rises with increasing age, and age has been shown to be an independent risk factor for surgical complications in scoliosis surgery. Previous studies have displayed increasing surgical frequency on elderly scoliotic patients in the last decade, but have not investigated complications in the same years. METHODS: ICD-9 coding identified elderly (age >/=75 yrs) patients with a primary diagnosis of scoliosis undergoing lumbar fusion or decompression. Analysis of variance (ANOVA) comparisons and linear trend analysis described changes from 2003 to 2012 in surgical invasiveness (Mirza scale: levels fused/decompressed/instrumented and by approach), intraoperative complications, and Charlson Comorbidity Index (CCI). Secondary outcome measures included cost and discharge outcomes. RESULTS: Eight thousand one elderly patients with ASD from 2003 to 2012 were included for analysis. Fusion incidence increased on average 13.8% per year (P < 0.001), surgical invasiveness by Mirza scale increased from 2.0 in 2003 to 5.9 in 2012 (P < 0.001), and CCI increased from 0.77 to 1.44 (p < 0.001). Over the same interval, elderly patients undergoing fusion displayed overall reduction in complications (excluding anemia)-from 26.7% to 8.6% (P < 0.001); specifically, surgical complications decreased from 11.7% to 0.7% (P < 0.001) and respiratory complications decreased from 6.7% to 1.4% (P = 0.004). CONCLUSION: From 2003 to 2012, surgical management of ASD in the elderly population increased in incidence and complexity, while number of patient comorbidities increased and in-hospital morbidity decreased. This may indicate increased willingness of surgeon's to operate on elderly patients, and reflect a development of overall understanding of deformity in the past decade. LEVEL OF EVIDENCE: 3.

STUDY DESIGN: Comparison between national administrative databases and a prospective multicenter physician managed database. OBJECTIVES: This study aims to assess the applicability of National Administrative Databases (NADs) in adult spinal deformity (ASD). Our hypothesis is that NADs do not include comparable patients as in a physician-managed database (PMD) for surgical outcomes in adult spinal deformity. SUMMARY OF BACKGROUND DATA: NADs such as National Inpatient Sample (NIS) and National Surgical Quality Improvement Program (NSQIP) provide large numbers of publications owing to ease of data access and lack of IRB approval requirement. These databases utilize billing codes, not clinical inclusion criteria, and have not been validated against PMDs in ASD surgery. METHODS: The NIS was searched for years 2002 to 2012 and NSQIP for years 2006 to 2013 using validated spinal deformity diagnostic codes. Procedural codes (ICD-9 and CPT) were then applied to each database. A multicenter PMD including years 2008 to 2015 was used for comparison. Databases were assessed for levels fused, osteotomies, decompressed levels, and invasiveness. Database comparisons for surgical details were made in all patients, and also for patients with >/= 5 level spinal fusions. RESULTS: Approximately, 37,368 NIS, 1291 NSQIP, and 737 PMD patients were identified. NADs showed an increased use of deformity billing codes over the study period (NIS doubled, 68x NSQIP, P < 0.001), but ASD remained stable in the PMD.Surgical invasiveness, levels fused and use of 3-column osteotomy (3-CO) were significantly lower for all patients in the NIS (11.4-13.7) and NSQIP databases (6.4-12.7) compared with PMD (27.5-32.3). When limited to patients with >/=5 levels, invasiveness, levels fused, and use of 3-CO remained significantly higher in the PMD compared with NADs (P < 0.001). CONCLUSION: National databases NIS and NSQIP do not capture the same patient population as is captured in PMDs in ASD. Physicians should remain cautious in interpreting conclusions drawn from these databases. LEVEL OF EVIDENCE: 4.

STUDY DESIGN: Retrospective analysis of three prospectively collected databases. OBJECTIVE: To compare perioperative outcomes in Adult Spinal Deformity (ASD) surgeries in a surgeon-run (SR-ASD) and two national databases: the Nationwide Inpatient Sample (NIS) and the National Surgical Quality Improvement Program (NSQIP). SUMMARY OF BACKGROUND DATA: Much has been learned on the treatment of ASD in the last decade with prospective multicenter collaborative research focusing on this specific condition. Nondisease specific national databases are being used for hypothesis and quality control testing on a large number of ASD patients. Their accuracy and applicability remains unevaluated. METHODS: Patients were identified on each respective database undergoing lumbar spine fusion for ASD. Propensity score matching established cohorts of patients on each database with similar procedures being performed. Complication prevalence and relative risk was compared on the NIS and NSQIP against SR-ASD. Secondary outcome measures included hospital-stay characteristics, surgical invasiveness, patient demographics, and patient comorbidities. RESULTS: Two hundred fifty-five patients were identified on each database 1:1:1 with similar overall surgical intensity. Querying the databases using ICD-9 codes, CPT codes, and surgeon-reports resulted in different complication incidences: overall complication rates were 17.65% on NIS, 24.31% on NSQIP, and 68.24% on SR-ASD. The relative risk of a medical complication in SR-ASD was 1.87 (1.42-2.48) relative to NIS and 1.91 (1.44-2.54) relative to NSQIP. The relative risk of a surgical complication was 5.45 (2.69-11.05) compared with NIS and 12.05 (3.98-36.49) compared with NSQIP. CONCLUSION: After selecting patients using the same criteria and diagnosis, NIS, NSQIP, and SR-ASD databases captured different patient populations and different complication incidences. There were total absences of certain complications contrary to usual literature rates in all three databases. Faithful reporting necessitates understanding database limitations, and careful evaluation of database strengths and weaknesses is paramount to accurate reports. LEVEL OF EVIDENCE: 3.

STUDY DESIGN: Retrospective study of an administrative database. OBJECTIVE: The objective was to investigate the incidence, risk factors, and mortality rate of reintubation after adult spinal deformity (ASD) surgery. BACKGROUND DATA: There are limited data regarding the occurrence of reintubation after ASD surgery. MATERIALS AND METHODS: The Nationwide Inpatient Sample database from 2002 to 2011 was used to identify adult patients who underwent elective surgery for scoliosis. Patients who required reintubation were identified and compared with controls (no reintubation). A multivariable logistic regression analysis was performed to identify independent factors associated with reintubation. RESULTS: A total of 9734 patients who underwent surgery for ASD were identified, and 182 required reintubation [1.8%; 95% confidence interval (CI), 1.6%-2.1%] on average 2 days after surgery (range, 0-28 d). After multivariable analysis, the strongest independent risk factors associated with reintubation included postoperative acute respiratory failure [odds ratio (OR), 12.0; 95% CI, 8.6-16.6], sepsis (OR, 6.9; 95% CI, 3.5-13.6), and deep vein thrombosis (OR, 5.7; 95% CI, 3.0-10.9); history of chronic lung disease (OR, 1.6; 95% CI, 1.1-2.3) and fusion of 8 or more segments (OR, 1.5; 95% CI, 1.1-2.2) were also independent risk factors. Mortality rates were significantly higher in reintubated patients (7.3%) compared with that in nonreintubated patients (0.2%, P<0.001). More importantly, reintubation was an independent risk factor for inpatient mortality (OR, 9.8; 95% CI, 4.1-23.5; P<0.001). CONCLUSIONS: The reintubation rate after ASD surgery is approximately 1.8%. Patients with a history of chronic lung disease and patients undergoing fusion of 8 or more segments may be at an increased risk for reintubation; other associated factors included acute respiratory failure, sepsis, and deep vein thrombosis. Patients who required postoperative airway management after ASD surgery were 9.8 times more likely to die during their hospital stay compared with controls.

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 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.

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.

OBJECT: We sought to create a model capable of predicting the magnitude of pelvic incidence-lumbar lordosis (PI-LL) correction necessary to achieve a desired change in sagittal vertical axis (SVA). METHODS: Retrospective review of a prospectively maintained multicenter adult spinal deformity database collected by the International Spine Study Group between 2009 and 2014. The independent variable of interest was the degree of correction achieved in the PI-LL mismatch at 6-weeks post-surgery. Primary outcome was the change in global sagittal alignment at 6 weeks and 1 year after surgery. We used a linear mixed-effects model to determine the extent to which corrections in the PI-LL relationship affected post-operative changes in SVA. RESULTS: A total of 1053 adult patients were identified. Of these, 590 were managed surgically. 87 surgically managed patients were excluded due to incomplete or missing PI-LL measurements on follow-up; the remaining 503 of these patients were selected for inclusion. For each degree of improvement in the PI-LL mismatch at 6 weeks, the SVA decreased by 2.18 mm (95% CI:-2.56, -1.79, p<0.01) and 1.67 mm (95% CI:-2.07, - 1.27, p<0.01) at 6 weeks and 12 months, respectively. A high SVA measurement (>50 mm) at 1-year post-surgery was negatively associated with health-related quality of life as measured by the SRS-12 outcomes assessment. CONCLUSION: We describe a novel model that illustrates how surgical correction of the PI-LL relationship affects post-operative changes in SVA. This may enable surgeons to determine pre-operatively the amount of lumbar lordosis necessary to achieve a desired change in SVA.