Faculty Bibliography

STUDY DESIGN: Retrospective analysis of prospective data from the degenerative spondylolisthesis (DS) arm of the Spine Patient Outcomes Research Trial. OBJECTIVE: To identify risk factors for reoperation in patients treated surgically for DS and compare outcomes between patients who underwent reoperation with non-reoperative patients. SUMMARY OF BACKGROUND DATA: Several studies have examined outcomes following surgery for DS, but few have identified risk factors for reoperation. METHOD: Analysis included patients with neurogenic claudication (>12 weeks), clinical neurological signs, spinal stenosis, and DS on standing lateral x-rays. Univariate and multivariate analyses were used to investigate patient characteristics and risk factors. Treatment effects (TE) were calculated and compared between study groups. RESULTS: Of 406 patients, 72% underwent instrumented fusion, 21% non-instrumented fusion, and 7% decompression alone. At 8 years, the reoperation rate was 22%, of which 28% occurred within one year, 54% within 2 years, 70% within 4 years, and 86% within 6 years. The reasons for reoperation included recurrent stenosis or progressive spondylolisthesis (45%), complications such as hematoma, dehiscence, or infection (36%), or new condition (14%). Re-operative patients were younger (62.2 vs 65.3, p = 0.008). Significant risk factors were use of antidepressants (p = 0.008, HR 2.08) or having no neurogenic claudication upon enrollment (p = 0.02, HR 1.82). Patients who were smokers, diabetics, obese, or on workman's compensation were not at greater risk for reoperation. At eight year follow-up, scores for SF-36 bodily pain (BP), ODI, and stenosis frequency index were better in non-re-operative patients. TE favored non-re-operative patients for SF-36 BP, physical function, ODI, stenosis bothersomeness index and satisfaction with symptoms (p < 0.001). CONCLUSION: The incidence of reoperation for patients with DS was 22% eight years following surgery. Patients with a history of no neurogenic claudication and patients taking antidepressants were more likely to undergo reoperation. Outcomes scores and TE were more favorable in non-re-operative patients. LEVEL OF EVIDENCE: 2.

OBJECTIVE: To report the outcome of adult spinal deformity (ASD) in patients with rod fracture (RF) after thoracolumbar fusion. METHODS: Retrospective review of prospective, multicenter database. Operative patients with ASD >/=18 years old with RF after ASD surgery and with a minimum 6-month follow-up after RF were included. Health-related quality of life scores and radiographic alignment were compared with nonparametric paired and independent testing (P < 0.05). RESULTS: A total of 51 of 343 patients with ASD (14.9%) sustained a RF, of whom 44 (86.3%) had at least 6-month follow up after RF (mean age = 61.2 years, mean body mass index = 29.6 kg/m2). Mean total follow-up was 37.8 months (range 24.5-66.7 months). Interbody fusion was used in 26 cases of RF (59.1%) (transforaminal lumbar interbody fusion, n = 17 [65.4%], anterior lumbar interbody fusion, n = 5 [19.2%]). RF was symptomatic in 26 of 44 (59.1%) of patients and discovered incidentally in 18 of 44 patients (40.9%). Overall, 28 RFs were revised (63.6%); 12 of 23 (52.2%) unilateral RF and 16 of 21 (76.2%) bilateral RF at last follow-up. Revision patients were significantly more likely to be symptomatic at the time of RF detection (78.6% vs. 25.0%, P = 0.0006), and had significantly worse Oswestry Disability Index and Scoliosis Research Society-22r pain scores. CONCLUSIONS: RFs were detected in 14.9% of patients with ASD and were most common at the L4-L5 and L5-S1 levels. Approximately 63.6% of patients underwent revision surgery. The decision to perform revision surgery may be based predominantly on symptoms referable to the RF, pain, and perceived disability, as radiographic parameters at the time of RF did not differ significantly between patients who did and did not undergo revision.

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.

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.