Faculty Bibliography

STUDY DESIGN: Measurement reliability study of adult spinal deformity (ASD) patient radiographs using intraclass correlation coefficients (ICC) and variance. OBJECTIVE: The aim of the study was to compare picture archiving and communication systems (PACS) to dedicated spine measurement software (SMS). SUMMARY OF BACKGROUND DATA: Accurate radiographic measurement of sagittal alignment is essential for evaluating ASD. PACS measurements often necessitate rudimentary techniques and estimations of anatomic landmarks and angles. Though SMS has been studied and validated, no studies directly compare PACS to SMS. METHODS: Eleven independent observers (7 spine surgeons, 4 researchers) digitally measured 20 ASD radiographs for pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), PI-LL, thoracic kyphosis (TK), and sagittal vertical axis (SVA). Round 1 used PACS basic line/angle tools; Round 2 used a validated SMS that automatically calculates spino-pelvic parameters from 6 user-identified landmarks. Means, coefficient of variance (CV), and intraclass correlation coefficients (ICC) were analyzed. RESULTS: PACS measurements were significantly greater than SMS (PI, PT, PI-LL: P < 0.0001), though within clinical and measurement margins of error. Excluding TK, the variations in measurement (CV) were significantly greater for PACS (14-34%) vs. SMS (11-23%). Reliability was greater in SMS than PACS for PI, PT, PI-LL, LL, and SVA. The greatest differences in intraclass correlation coefficients (ICC) between PACS and SMS were in PI (PACS: 0.647; SMS: 0.810) and PI-LL (PACS: 0.921; SMS: 0.970). Among surgeons, the differences between PACS and SMS were augmented, and SMS had higher intraclass correlation coefficients (ICC) than PACS for all parameters (mean intraclass correlation coefficients [ICC] 0.931 vs. 0.861). Among surgeons, PI had the lowest reliability ( PACS: 0.505; SMS: 0.752) and SVA had the highest ( PACS: 0.985; SMS: 0.994). CONCLUSION: SMS provides significantly more reliable measurements than PACS, especially among surgeons. Consistent use of SMS in the evaluation and surgical planning of ASD patients appears necessary given the significant differences in values, variance, and reliability between PACS and SMS. LEVEL OF EVIDENCE: 3.

There exist no population-based examinations of stereotactic radiosurgery (SRS) of the spine. To address this, spinal SRS was analyzed using the New Jersey State Ambulatory Surgery and Services Database (SASD) and Nationwide Inpatient Sample (NIS) over 10-year periods. The SASD is a state-specific ambulatory surgery and outpatient database, while the NIS database comprises approximately 20% of all nonfederal hospital inpatient admissions and discharges in the United States. Only patients receiving SRS for at least one spinal lesion were included (ICD-9-CM=92.3x; diagnosis codes=63620,63621). 4,194,207 patients were contained in the New Jersey SASD from 2003-2012, of whom fewer than 0.0003% received SRS of any sort, with none receiving SRS of the spine. Of the 78,686,628 patients contained in the NIS, only 16 (0.00002%) received radiosurgery, none of whom received SRS of the spine. In conclusion, a decade-long analysis of the NIS and SASD from the most densely populated state in the United States revealed that no patients received spinal SRS with virtually none receiving SRS of any sort. Given the improbability of these findings, it is much more likely that neither the NIS nor SASD can accurately capture patients receiving SRS. Accurate characterization of the incidence and usage of spinal SRS will require databases less reliant on ICD-9 coding than the SASD or NIS.

BACKGROUND: Some studies have suggested patients who undergo surgery in July have worse outcomes compared to patients treated during other months. The purpose of this study is to compare inpatient morbidity and mortality among patients who underwent adult spinal deformity (ASD) surgery in July with those who underwent surgery in other months. METHODS: Admission data for patients who underwent ASD surgery were extracted from the Nationwide Inpatient Sample for the years 2002 to 2011. Only adult patients (over 21 years of age) and elective admissions to teaching hospitals were included. A multivariable regression analysis was performed to examine the independent effect of July admissions on overall complications, major complications, and inpatient mortality. RESULTS: A total of 27,794 patients were identified, with 2,023 (7.8%) admitted in July and 25,771 (92.2%) in other months. Overall complication rates in July (43.1%) were not different from rates in other months (44.9%, p=0.468). Similarly, major complication rates were similar; 12.9% in July and 12.4% in other months (p=0.764). Mortality was not different between groups (p=0.807). After multivariable analysis, July admissions were not found to increase the odds of developing any complication (OR 0.94; 95% CI, 0.77 - 1.12; p=0.403), major complications (OR 1.04; 95% CI, 0.76 - 1.41; p=0.788) or inpatient mortality (OR 1.35; 95% CI, 0.31 - 5.84; p=0.684). CONCLUSION: In this study of a nationwide database, patients who underwent ASD surgery in July did not have increased odds of developing a complication or inpatient mortality compared to patients admitted in other months.

BACKGROUND: In a bundled payment system, a single payment covers all costs associated with a single episode of care. Spine surgery may be well suited for bundled payments because of clearly defined episodes of care, but the impact on current practice has not been studied. We sought to examine how a theoretical bundled payment strategy with financial disincentives to resource utilization would impact practice patterns. METHODS: A multiple-choice survey was administered to spine surgeons describing eight clinical scenarios. Respondents were asked about their current practice, and then their practice in a hypothetical bundled payment system. Respondents could choose from multiple types of implants, bone grafts, and other resources utilized at the surgeon's discretion. RESULTS: Forty-three respondents completed the survey. Within each scenario, 24%-49% of respondents changed at least one aspect of management. The proportion of cases performed without implants was unchanged for four scenarios and increased in four by an average of 8%. Use of autologous iliac crest bone graft increased across all scenarios by an average of 18%. Use of neuromonitoring decreased in all scenarios by an average of 21%. Differences in costs were not statistically significant. CONCLUSIONS: Financial disincentives to resource utilization may result in some changes to surgeons' practices but these appear limited to items with less clear benefits to patients. Choices of implants, which account for the majority of intra-operative costs, did not change meaningfully. A bundling strategy targeting peri-operative costs solely related to surgical practice may not yield substantive savings while rationing potentially beneficial treatments to patient care. LEVEL OF EVIDENCE: 5.

PURPOSE: The aim of this study is to report and quantify the associated factors for morbidity and mortality following surgical management of cervical spondylotic myelopathy (CSM). METHODS: The Nationwide Inpatient Sample (NIS) database was use to retrospectively review all patients over 25 years of age with a diagnosis of CSM who underwent anterior and/or posterior cervical fusion or laminoplasty between 2001 and 2010. The main outcome measures were total procedure-related complications and mortality. Multivariate regression analysis was used to identify demographic, comorbidity, and surgical parameters associated with increased morbidity and mortality risk [reported as: OR (95 % CI)]. RESULTS: A total of 54,348 patients underwent surgical intervention for CSM with an overall morbidity rate of 9.83 % and mortality rate of 0.43 %. Comorbidities found to be associated with an increased complication rate included: pulmonary circulation disorders [6.92 (5.91-8.12)], pathologic weight loss [3.42 (3.00-3.90)], and electrolyte imbalance [2.82 (2.65-3.01)]. Comorbidities found to be associated with an increased mortality rate included: congestive heart failure [4.59 (3.62-5.82)], pulmonary circulation disorders [11.29 (8.24-15.47)], and pathologic weight loss [5.43 (4.07-7.26)]. Alternatively, hypertension [0.56 (0.46-0.67)] and obesity [0.36 (0.22-0.61)] were found to confer a decreased risk of mortality. Increased morbidity and mortality rates were also identified for fusions of 4-8 levels [morbidity: 1.55 (1.48-1.62), mortality: 1.80 (1.48-2.18)] and for age >65 years [morbidity: 1.65 (1.57-1.72), mortality: 2.74 (2.25-3.34)]. An increased morbidity rate was found for posterior-only [1.55 (1.47-1.63)] and combined anterior and posterior fusions [3.20 (2.98-3.43)], and an increased mortality rate was identified for posterior-only fusions [1.87 (1.40-2.49)]. Although revision fusions were associated with an increased morbidity rate [1.81 (1.64-2.00)], they were associated with a decreased rate of mortality [0.24 (0.10-0.59)]. CONCLUSION: The NIS database was used to provide national estimates of morbidity and mortality following surgical management of CSM in the United States. Several comorbidities, as well as demographic and surgical parameters, were identified as associated factors.

OBJECT Lenke 1C curves are challenging to manage surgically due to the structural thoracic deformity and nonstructural lumbar curve. Selective thoracic fusion (STF) is considered the standard of care because it preserves motion of the lumbar segment, yet nonselective STF (NSTF) remains prevalent. This study aims to identify baseline patient characteristics that drive treatment and to compare postoperative outcomes for both procedures. METHODS Studies that compared baseline and postoperative demographic data, health-related quality of life (HRQL) questionnaires, and radiographic parameters of patients with Lenke 1C curves undergoing STF or NSTF were identified for meta-analysis. The effect measure is expressed as a mean difference (MD) with 95% CI. A positive MD signifies a greater STF value, or a mean increase within the group. RESULTS One prospective and 6 retrospective case-control studies with sample size of 488 patients (344 STF and 144 NSTF) were identified. Baseline age, sex, and HRQLs were equivalent, except for better scores in the STF group for the Scoliosis Appearance Questionnaire (SAQ): Unrelated to Deformity item (3.47 vs 3.88, p = 0.01) and the Spine Research Society questionnaire, Item 22: Pain (4.13 vs 3.92, p = 0.04). Radiographic findings were significantly worse in NSTF, as measured by the thoracolumbar/lumbar (TL/L) Cobb angle (MD: -4.29 degrees , p < 0.01) and TL/L apical vertebral translation (AVT) (MD: -6.08, p < 0.01). Radiographic findings significantly improved in STF, as measured in the main thoracic (MT) Cobb angle (MD: -27.78 degrees , p < 0.01), TL/L Cobb angle (MD: -16.24 degrees , p < 0.01), MT:TL/L Cobb ratio (MD: -0.21, p < 0.01), coronal balance (MD: 0.47, p = 0.02), and thoracic kyphosis (MD: 7.87 degrees , p < 0.01); and in NSTF in proximal thoracic (PT) Cobb angle (24 degrees vs 14.1 degrees , p < 0.01), MT Cobb angle (53.5 degrees vs 20.5 degrees , p < 0.01), and TL/L Cobb angle (41.6 degrees vs 16.6 degrees , p < 0.01). Postoperative TL/L Cobb angle (23.1 degrees vs 16.6 degrees , p < 0.01) was significantly higher in STF; but PT Cobb angle, MT Cobb angle, and MT:TL/L Cobb ratio are equivalent. CONCLUSIONS Patients with larger lumbar compensatory curves displaying a larger degree of coronal translation, as measured by the TL/L AVT, are more likely to undergo an NSTF. Contrary to established guidelines, larger MT curve magnitudes and MT:TL/L Cobb angle ratios have not been found to influence the decision to pursue a selective thoracic fusion. Although overall both STF and NSTF groups are found to have effective postoperative coronal balance, the STF group has only modest improvements in the lumbar curve position as determined by a relatively unchanged TL/L AVT. Furthermore, surgeons may prefer NSTF in patients who may have a worse overall perception of their spinal deformity as measured by HRQL measures of pain and desire for appearance change.

BACKGROUND: A key component toward improving surgical outcomes is proper patient selection. Improved selection can occur through exploration of prognostic studies that identify variables which are associated with good or poorer outcomes with a specific intervention, such as lumbar discectomy. To date there are no guidelines identifying key prognostic variables that assist surgeons in proper patient selection for lumbar discectomy. The purpose of this study was to identify baseline characteristics that were related to poor or favourable outcomes for patients who undergo lumbar discectomy. In particular, we were interested in prognostic factors that were unique to those commonly reported in the musculoskeletal literature, regardless of intervention type. METHODS: This retrospective study analysed data from 1,108 patients who underwent lumbar discectomy and had one year outcomes for pain and disability. All patient data was part of a multicentre, multi-national spine repository. Ten relatively commonly captured data variables were used as predictors for the study: (1) age, (2) body mass index, (3) gender, (4) previous back surgery history, (5) baseline disability, unique baseline scores for pain for both (6) low back and (7) leg pain, (8) baseline SF-12 Physical Component Summary (PCS) scores, (9) baseline SF-12 Mental Component Summary (MCS) scores, and (10) leg pain greater than back pain. Univariate and multivariate logistic regression analyses were run against one year outcome variables of pain and disability. RESULTS: For the multivariate analyses associated with the outcome of pain, older patients, those with higher baseline back pain, those with lesser reported disability and higher SF-12 MCS quality of life scores were associated with improved outcomes. For the multivariate analyses associated with the outcome of disability, presence of leg pain greater than back pain and no previous surgery suggested a better outcome. CONCLUSIONS: For this study, several predictive variables were either unique or conflicted with those advocated in general prognostic literature, suggesting they may have value for clinical decision making for lumbar discectomy surgery. In particular, leg pain greater than back pain and older age may yield promising value. Other significant findings such as quality of life scores and prior surgery may yield less value since these findings are similar to those that are considered to be prognostic regardless of intervention type.

STUDY DESIGN: Retrospective review of a prospectively collected database. OBJECTIVE: This study compares patient demographics, incidence of comorbidities, procedure-related complications, and mortality following primary vs. revision adult spinal deformity surgerySummary of Background Data. While adult spinal deformity (ASD) surgery has been extensively investigated, no previous study has provided nationwide estimates of patient characteristics and procedure-related complications for primary vs. revision spinal deformity surgery comparatively. METHODS: Nationwide Inpatient Sample data collected between 2001 and 2010 was analyzed. Discharges with procedural codes for anterior and/or posterior thoracic and/or lumbar spinal fusion and refusion were included for patients aged 25+ and 4+ levels fused with any diagnoses specific for scoliosis. Patient demographics, comorbidity and procedure-related complications incidence were determined for primary vs. revision cohorts. Multivariate analysis reported as (OR [95% CI]). RESULTS: Discharges for 9133 primary and 850 revision cases were identified. Patients differed on the basis of demographic and hospital data. Average comorbidity indices for the cohorts were similar (p = 0.580), as was in-hospital mortality (p = 0.163). The incidence of procedure-related complications was higher for the revision cohort (46.96% vs. 71.97%, p = 0.001). The mean hospital course for the revision cohort was longer (6.37 vs. 7.13 days, p<0.0001). Revisions had an increased risk of complications involving the nervous system (1.34[1.10-1.6]), hematoma/seroma formation (2.31[1.92-2.78]), accidental vessel or nerve puncture (1.44[1.29-1.61]), wound dehiscence (2.18[1.48-3.21]), post-op infection (3.10[2.50-3.85]) and ARDS complications (1.43[1.28-1.60]). The primary cohort had a decreased risk for GI (0.65[0.55-0.76]) and GU complications (0.71[0.51-0.99]). CONCLUSIONS: Relative to primary cases, those undergoing revision correction of spinal deformity have a higher risk of many procedure-related complications with a longer hospital course despite similar baseline comorbidity burden and in-hospital mortality rate. This study provides clinically useful data for surgeons to educate patients at risk for morbidity and mortality and direct future research to improve outcomes.

BACKGROUND CONTEXT: Although adult cervical deformity (ACD) can have profound impact on function and health-related quality of life, few reports have focused on the treatment of these patients. We present early complication rates associated with surgical treatment for ACD based on a prospective multicenter cohort. Accurately defining the early complication rates is particularly important for patient counseling with regard to the risks and benefits of surgical treatment. PURPOSE: Assess early complication rates associated with the surgical treatment of ACD based on a prospective multicenter cohort. STUDY DESIGN/SETTING: Prospective multicenter cohort. PATIENT SAMPLE: ACD patients treated surgically. OUTCOME MEASURES: Occurrence of early (within 30 days from surgery) minor and major complications. METHODS: Prospective multicenter database of operative ACD patients from 2013-2014 were reviewed for early (<30 days from surgery) complications. Database enrollment required at least one of the following: cervical kyphosis >10degree, cervical scoliosis >10degree, C2-7 sagittal vertical axis >4cm or chin-brown vertical angle >25degree. Patients with ACD due to neoplasm or acute infection were excluded. RESULTS: 78 patients (59% women) underwent surgical treatment for ACD and had a mean age of 60.7 years (range 37-81 years), mean Charlson Comorbidity Index of 0.6 (range 0-6) and previous surgery in 52%. Surgical approaches included anterior-only (A, 14%), posterior-only (P, 49%), anterior-posterior (AP, 35%) and posterior-anterior-posterior (PAP, 3%). Mean numbers of fused anterior and posterior vertebral levels were 4.7 and 9.4, respectively. A total of 52 early complications were reported, including 26 minor and 26 major for an overall complication rate of 66.7%. 22 (28.2%) patients had at least one minor complication, and 19 (24.4%) had at least one major complication. Overall, 34 (43.6%) patients had one or more complication. The most common complications included dysphagia (11.5%), deep wound infection (6.4%), new C5 motor deficit (6.4%), respiratory failure (5.1%), new nerve root (not C5) motor deficit (3.8%), new nerve sensory deficit (3.8%), and superficial wound infection (3.8%). Less common complications included pulmonary embolism, cardiac arrest, arterial injury, instrumentation malposition, and mortality (respiratory arrest 1 week postop), excessive (>4L) bleeding (each occurring in 1.3%). Overall early complication rates were significantly different based on approach: A (27.3%), P (68.4%), AP/PAP (79.3%) (p=0.007). CONCLUSIONS: Among 78 patients treated for ACD and prospectively followed, a total of 52 complications were reported (26 minor and 26 major), including 1 mortality. Overall, 34 (43.6%) patients had one or more complication and 24.4% of patients had one or more major complication. Significantly higher rates of complications were associated with combined and posterior-only approaches compared with anterior-only approaches. These findings may prove useful in treatment planning and patient counseling