Faculty Bibliography

PURPOSE: The resection point of a lumbar three-column osteotomy (3CO) creates separation of the spino-pelvic complex. This study investigates the impact of patients' baseline deformity and level of 3CO resection on the distribution of correction between the trunk and the pelvis following osteotomy closure. METHODS: Patients who underwent single lumbar 3CO, upper instrumented vertebra (UIV) T1-T10, and 6 month follow-up were included. The truncal and pelvic closures were calculated based on the vertebrae adjacent to the osteotomy level and the impact of radiographic parameters and level of 3CO on the closures were analyzed. RESULTS: 113 patients were included. Patients who experienced more pelvic correction had significantly higher Pelvic Tilt and lower Sagittal Vertical Axis at baseline. Patients who underwent more caudal osteotomies with higher pelvic compensation with modest SVA sustained more pelvic correction. CONCLUSIONS: The osteotomy closure is driven by patient's specific deformity. More caudal osteotomy level leads to greater pelvic tilt improvement. LEVEL OF EVIDENCE: III.

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.

BACKGROUND: The surgical procedure to treat adult spinal deformity is challenging, with high rates of complications, including revision procedures performed to repair instrumentation failure or unplanned surgical complications. This study quantifies the incidence of, identifies predictors for, and determines health-related quality-of-life changes associated with revision procedures to treat adult spinal deformity. METHODS: We analyzed a multicenter database of patients who underwent a surgical procedure for adult spinal deformity, which was defined as having an age of eighteen years or older and scoliosis of >/=20 degrees , sagittal vertical axis of >/=5 cm, pelvic tilt of >/=25 degrees , and/or thoracic kyphosis of >60 degrees . We focused on demographic, radiographic, health-related quality-of-life, and operative data at the two-year follow-up. Patients with primary infections were excluded. Predictive and confounding variables for revisions were identified using univariate analysis and multivariate logistic regression modeling. RESULTS: Two hundred and forty-three patients were included in this study; of these patients, forty (16.5%) underwent a revision surgical procedure (15% of these at six weeks, 38% between six weeks and one year, and 48% between one and two years). Screw or cage-related implant complications were the most common indications for revision, followed by proximal junctional kyphosis and rod failure. Positive predictors for a revision surgical procedure included total body mass, with an odds ratio of 1.33 (95% confidence interval, 1.04 to 1.70) per 10-kg increase, and preoperative sagittal vertical axis, with an odds ratio of 1.15 (95% confidence interval, 1.04 to 1.28) per 2-cm increase. Factors associated with lower risk of revision included use of bone morphogenetic protein-2 (BMP-2) (odds ratio, 0.16 [95% confidence interval, 0.05 to 0.47]) and greater diameter rods (odds ratio, 0.51 [95% confidence interval, 0.29 to 0.89]). Body mass index, although initially considered a potential predictor for a revision surgical procedure, was not significantly different between primary and revision cohorts on univariate analysis and was therefore not input into the multivariate model. All patients improved in two-year health-related quality-of-life scores; revision subjects had lower overall improvement (Scoliosis Research Society [SRS] score; p = 0.016) from baseline. Revision status did not predict two-year patient satisfaction (p = 0.726), as measured by the SRS Satisfaction domain (SRS-22r). CONCLUSIONS: Patients with greater preoperative sagittal vertical axis and high total body mass are at a higher risk for a revision surgical procedure following procedures to treat adult spinal deformity. Larger diameter rods and BMP-2 were associated with decreased revision odds. Revisions did not impact patient satisfaction at two years. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

STUDY DESIGN: A retrospective review of a prospective multicenter database. OBJECTIVE: The aim of this study was to identify variables associated with extended length of stay (ExtLOS) and this impact on health-related quality of life (HRQoL) scores in adult spinal deformity (ASD) patients. SUMMARY OF BACKGROUND DATA: ASD surgery is complex and associated with complications including extLOS. Although variables contributing to extLOS have been considered, specific complications and pre-disposing factors among ASD surgical patients remain to be investigated. METHODS: INCLUSION CRITERIA: ASD surgical patients (age >18 years, scoliosis >/=20 degrees , sagittal vertical axis >/=5 cm, pelvic tilt >/=25 degrees , and/or thoracic kyphosis >60 degrees ) with complete demographic, radiographic, and HRQoL data at baseline, 6 weeks, and 2 years postoperative. ExtLOS was based on 75th percentile (>/=9 days). Univariate and multivariate analyses identified predictors and evaluated effects on outcomes. Repeated-measures mixed models analyzed impact of ExtLOS on HRQoL [Oswestry Disability Index; Short Form-36 physical component summary/mental component summary; SRS22r Activity (AC), Pain (P), Appearance (AP), Satisfaction (S), Mental (M) and Total (T)]. RESULTS: Three hundred eighty patients met inclusion criteria: 105 (27.6%) had extLOS (>/=9 days) and 275 (72.4%) did not. Average LOS was 8 days (range: 1-30 days). Age [odds ratio (OR) 1.04], no. of levels fused (OR 1.12), no. of infections (OR 2.29), no. of neurologic complications (OR 2.51), Charlson Comorbidity Index Score (CCI) predicted ExtLOS (OR 3.92), and no. of intraop complications predicted ExtLOS (OR 3.56). ExtLOS patients had more intracardiopulmonary (pleural effusion: 1.9% vs. 0%) and operative complications (dural tear: 13.3% vs. 5.1%; excessive blood loss: 18% vs. 5.8%) (P < 0.022). At 2 years, both groups of patients experienced an overall improvement in all HRQoL scores (P < 0.001). ExtLOS patients had significantly less overall improvement in all HRQoLs (P < 0.01) except for MCS (P = 0.17) and SRS M (P = 0.08). CONCLUSION: Extended LOS of ASD patients is affected by comorbidities (higher CCI) and number of intraoperative, but not peri-operative, complications. All patients improved overall in HRQoL scores, but extended LOS patients improved less overall at 2 years in comparison. LEVEL OF EVIDENCE: 3.

OBJECTIVE: Although previous reports suggest that surgery can improve the pain and disability of cervical spinal deformity (CSD), techniques are not standardized. Our objective was to assess for consensus on recommended surgical plans for CSD treatment. METHODS: 18 CSD cases were assembled, including a clinical vignette, cervical imaging (x-rays, CT/MRI), and full-length standing x-rays. Fourteen deformity surgeons (10 orthopedic, 4 neurosurgery) were queried regarding recommended surgical plan. RESULTS: There was marked variation in treatment plans across all deformity types. Even for the least complex deformities (moderate mid-cervical apex kyphosis), there was lack of agreement on approach (50% combined anterior-posterior, 25%, anterior-only, 25% posterior-only), number of anterior (range: 2-6) and posterior (range: 4-16) fusion levels, and types of osteotomies. As the kyphosis apex moved caudally (cervical-thoracic junction/upper thoracic spine) and for cases with chin-on-chest kyphosis, >80% of surgeons agreed on a posterior-only approach and >70% recommended a pedicle subtraction osteotomy (PSO) or vertebral column resection (VCR), but the range in number of anterior (4-8) and posterior (4-27) fusion levels was exceptionally broad. Cases of cervical/cervical-thoracic scoliosis had the least agreement for approach (48% posterior-only, 33% combined anterior-posterior, 17% anterior-posterior-anterior or posterior-anterior-posterior, 2% anterior-only) and had broad variation in number of anterior (2-5) and posterior (6-19) fusion levels, and recommended osteotomies (41% PSO/VCR). CONCLUSIONS: Among a panel of deformity surgeons, there was marked lack of consensus on recommended surgical approach, osteotomies and fusion levels for CSD. Further study is warranted to assess whether specific surgical treatment approaches are associated with better outcomes.

Prolonged length of stay (PLOS) has been associated with increased hospital resource utilization and worsened patient outcomes in multiple studies. In this study, we defined and identified factors associated with PLOS after posterior surgery for cervical spondylotic myelopathy in patients over the age of 65. PLOS was defined as length of stay beyond the "prolongation point" (that is, the day after which discharge rates begin to decline). Using the United States Nationwide Inpatient Sample database, 2742 patients met inclusion criteria, out of whom 16.5% experienced PLOS (stay beyond 6days). After multivariate analysis, increasing age was independently associated with PLOS (odds ratio [OR] 1.04, 95% confidence interval [CI] 1.02-1.06). Multiple comorbid conditions were associated with PLOS, including alcohol abuse (OR 3.85, 95% CI 1.87-7.94), congestive heart failure (OR 1.72, 95% CI 1.11-2.64), obesity (OR 1.70, 95% CI 1.14-2.55), and deficiency anemia (OR 1.44, 95% CI 1.01-2.05); the strongest associated operative parameter was blood transfusion (OR 2.39, 95% CI 1.75-3.28). Major complications independently associated with PLOS were deep vein thrombosis (OR 18.32, 95% CI 6.50-51.61), myocardial infarction (OR 8.98, 95% CI 2.92-27.56), pneumonia (OR 6.67, 95% CI 3.17-14.05), acute respiratory failure (OR 6.27, 95% CI 3.43-11.45), hemorrhage/hematoma (OR 5.04, 95% CI 2.69-9.44), and implant-related complications (OR 2.49, 95% CI 1.24-4.98). Average total hospital charges for patients who experienced PLOS were $122,965 US dollars, compared to $76,870 for the control group (p<0.001). Mortality for patients who experienced PLOS was 2.7% versus 0.5% for patients who did not epxerience PLOS (p<0.001). In conclusion, patients over the age of 65 who underwent posterior surgery for cervical myelopathy and stayed over 6days in hospital were defined as having PLOS. Hospital charges and mortality rates were significantly higher for patients who experienced PLOS. Potentially modifiable and/or preventable risk factors were also identified.

PURPOSE: Characteristics specific to cervical deformity (CD) concomitant with adult thoracolumbar deformity (TLD) remains uncertain, particularly regarding treatment. This study identifies cervical malalignment prevalence following surgical and conservative TLD treatment through 2 years. METHODS: Retrospective analysis of a prospective, multicenter adult spinal deformity (ASD) database. CD was defined in operative and non-operative ASD patients according to the following criteria: T1 Slope minus Cervical Lordosis (T1S-CL) >/=20 degrees , C2-C7 Cervical Sagittal Vertical Axis (cSVA) >/=40 mm, C2-C7 kyphosis >10 degrees . Differences in rates, demographics, health-related quality of life (HRQoL) scores for Oswestry Disability Index (ODI) and Scoliosis Research Society Questionnaire (SRS-22r), and radiographic variables were assessed between treatment groups (Op vs. Non-Op) and follow-up periods (baseline, 1-year, 2-year). RESULTS: Three hundred and nineteen (200 Op, 199 Non-Op) ASD patients were analyzed. Op patients' CD rates at 1 and 2 years were 78.9, and 63.0 %, respectively. Non-Op CD rates were 21.1 and 37.0 % at 1 and 2 years, respectively. T1S-CL mismatch and cSVA malalignment characterized Op CD at 1 and 2 years (p < 0.05). Op and Non-Op CD groups had similar cervical/global alignment at 1 year (p > 0.05 for all), but at 2 years, Op CD patients had worse thoracic kyphosis (TK), T1S-CL, CL, cSVA, C2-T3 SVA, and global SVA compared to Non-Ops (p < 0.05). Op CD patients had worse ODI, and SRS Activity at 1 and 2 years post-operative (p < 0.05), but had greater 2-year SRS Satisfaction scores (p = 0.019). CONCLUSIONS: In the first study to compare cervical malalignment at extended follow-up between ASD treatments, CD rates rose overall through 2 years. TLD surgery, resulting in higher CD rates characterized by T1S-CL and cSVA malalignment, produced poorer HRQoL. This information can aid in treatment method decision-making when cervical deformity is present concomitant with TLD.

PURPOSE: Studies have examined infection rates following spine surgery and their relationship to post-operative complications and increased length of stay. Few studies, however, have investigated predictors of infection, specifically in the setting of operative intervention for cervical spondylotic myelopathy (CSM). This study aims to identify the incidence and factors predictive of infection amongst this cohort. METHODS: This study performed a retrospective review of the prospectively collected American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. Patients included those treated surgically for CSM (ICD-9 code 721.1) from 2010 to 2012. Patient demographics and surgical data were collected with outcome variables including the occurrence of one of the following surgical site infections (SSIs) within 30 days of index operation: superficial SSI, deep incisional SSI, and organ/space SSI. RESULTS: 3057 patients were included in this analysis. Overall infection rate was 1.15 % (35/3057), of which 54.3 % (19/35) were superficial SSIs, 28.6 % (10/35) were deep incisional SSI, and 20 % (7/35) were peri-spinal SSI. Logistic regression revealed factors associated with SSI included: higher BMI [OR 1.162 (CI 1.269-1.064), p = 0.001] and operative time >/=208 min [OR 4.769 (CI 20.220-1.125), p = 0.034]. CONCLUSIONS: The overall SSI rate for the examined CSM cohort was 1.15 %. This study identified increased BMI and operative time >/=208 min as predictors of infection in surgical CSM patients. This information should be carefully considered in delivering patient education and future efforts to optimize risk in CSM patients indicated for surgical intervention.

STUDY DESIGN: Retrospective review of prospective multicenter database. OBJECTIVE: Identify factors influencing readmission, reoperation, and the impact on health related quality of life outcomes (HRQoL's) in adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND DATA: Many ASD patients experience complications requiring readmission. It is important to identify baseline/operative factors leading to rehospitalizations and reoperation, which may impact outcomes. METHODS: Inclusion criteria: ASD surgical patients (age > 18years, major coronal Cobb>/=20 degrees , SVA>/=5 cm, PT>/=25 degrees and/or TK > 60 degrees ) with complete baseline, 1-, and 2-year follow-up. Patients were grouped on the basis of readmission occurrence (yes/no) and type (medical [no reoperation] vs. surgical [revision surgery]). Readmissions caused by infections requiring surgical treatment (e.g. deep infections) were considered reoperations. Univariate and multivariate analyses determined readmission and reoperation predictors. Repeated measures mixed models evaluated readmission impact on HRQoL's at 1- and 2-years. RESULTS: 334 patients were included: 76 (22.8%) readmissions, involving 65 (85.5% of 76) reoperations (surgical readmission) and 11 (14.5% of 76) medical readmissions. The most common surgical readmission indication (n = 65) was implant complications (36.9%; rod breakage n = 13); the most common medical readmission indication was infection (36.4%, n = 4), treated with antibiotics. Non-infectious medical readmission (n = 7) included: pleural effusion, DTV, intra-operative blood loss, neurologic, and unspecified. Readmission predictors: increased number of major peri-operative complications (OR 5.13, p = 0.014), infection presence (OR 25.02, p = 0.001), implant complications (OR 6.12, p < 0.001), and radiographic complications (DJK, PJK, pseudoarthrosis, sagittal/coronal imbalance) (OR 16.94, p < 0.001). HRQoL analysis revealed overall improvement of the full cohort (p < 0.01), though the 76 readmitted improved less overall and at each time point p < 0.001) except in 6-week MCS (p = 0.14). CONCLUSIONS: Major peri-operative, implant, radiographic, and infection complications during index were associated with increased readmission odds. Implant complications most frequently caused surgical readmissions. Readmitted patients improved in outcome scores, although less compared to the non-readmitted cohort, yet displayed reduced 6-week SF-36 MCS. LEVEL OF EVIDENCE: 3.

BACKGROUND/AIMS: Surgical techniques for effective high-grade spondylolisthesis (HGS) remain controversial. This study aims to evaluate radiographic/clinical outcomes in HGS patients treated using modified "Reverse Bohlman" (RB) technique. METHODS: Review of consecutive HGS patients undergoing RB at a single university-center from 2006 to 2013. Clinical, surgical, radiographic parameters collected. RESULTS: Six patients identified: five with L5-S1 HGS with L4-L5 instability and one had an L4-5 isthmic spondylolisthesis and grade 1 L5-S1 isthmic spondylolisthesis. Two interbody graft failures and one L5-S1 pseudoarthrosis. Postoperative improvement of anterolisthesis (62.3% vs. 49.6%, p = 0.003), slip angle (10 vs. 5 degrees , p = 0.005), and lumbar lordosis (49 vs. 57.5 degrees , p = 0.049). CONCLUSIONS: RB technique for HGS recommended when addressing adjacent level instability/slip.