Faculty Bibliography

Cervical deformity (CD) can be debilitating. Surgery forsevere CD has high rates of radiographic and clinical failure. Among66 patients with severe CD, 62% had failure of radiographic correction at 1 year. Failed corrections were associated with worse baselinecervical alignment, male gender and greater intraoperative blood loss.Patients with failed corrections had less improvement in NDI at6 months and 1 year. More patients with successful correctionsattained MCID for NDI (84.2%) at 6 months.Hypothesis: Surgery for severe CD is challenging and there are highrates of radiographic and clinical failure.Design: Prospective cohort study.Introduction: Cervical malalignment is associated with disability.Surgical corrections of severe CD present considerable challenges.Demographic, surgical and postop factors associated with failedradiographic and clinical outcomes have not been well established.Methods: A prospective database of operative CD patients (Inclusioncriteria: cervical kyphosis[10, cervical scoliosis [10, cSVA [4 cm or CBVA [25) was analyzed. Inclusion was restricted tosevere baseline cervical deformities (cSVA [4 cm or C2 Slope(C2S) [20) and 1 year follow-up. Failed surgeries was defined ascSVA [4 cm at 1 year while successful surgery was defined ascSVA\4 cm at 1 year. Successful surgeries were compared to failedones with health related outcome measures, including the MCID forNDI (improvement [7).Results: 66 patients with severe CD met inclusion criteria, including41 failed (62%) surgery and 25 successful. Failed surgery patients hadworse alignment at baseline and 1 year by cSVA, C2S, T1S, TS-CL,and CTPA (p<0.05). Failed surgery patients were more commonlymale (51.2 vs 12%, p <0.01) and had greater intraop blood loss (1.2vs. 44L, p <0.01). History of prior cervical fusion, age, frailty, fusionlength, op-time, use of 3CO, DJK rate, and revision surgery were notassociated with failed surgery. Patients with failed surgery had lessimprovement in clinical outcomes by NDI at 6 months (-8.6 vs-21.7, p <.05) and 1 year (-7.7 vs-17.6, p <.05). Morepatients with successful surgery attained MCID for NDI at 6 months(84.2 vs 51.7%, p = 0.02) but there was no sig difference at 1 year(76.0 vs 56.8%, p = 0.12).Conclusions: Baseline cervical malalignment, male gender and intraop blood loss were associated with failed radiographic outcomes inpatients with severe CD. Failed surgery patients had less improvement in NDI at 6 months and 1 year. More patients with successfulsurgeries attained MCID for NDI at 6 months. In correcting severeCD, surgeons need to obtain optimal radiographic alignment to attainbetter clinical outcomes

Chiari malformations are structural defects in the posterior fossa where the cerebellum displaces caudally into the foramen magnum and upper spinal canal. These malformations are classified by severity as Types 1-4, each presenting with different associated and/or concurrent conditions and anomalies. The aim of this study was to utilize a nationwide database to study patients with Chiari malformations including their concurrent diagnoses and associated anomalies. Using a retrospective review of the Nationwide Inpatient Sample (NIS) database from 2003 to 2012, Chiari malformations were assessed by Chiari type and rates of concurrence for various additional anomalies were evaluated using cross-tabulations. There were 305,726 national cases of Chiari Type 1, 119,632 cases of Chiari Type 2, 15,540 cases of Type 3, and 79,663 cases of Type 4. Overall 44.3% of Chiari patients have at least one concurrent anomaly. Stratified by Chiari Type, 7.1% of Type 1 patients, 12.3% of Type 2, and 100% of Type 3 and 4 have at least one concurrent anomaly. The most common isolated neurologic associations were tethered cord, syringomyelia, and hydrocephalus, while the most common anomaly clusters were syringomyelia and scoliosis in Type 1 (0.63), tethered cord syndrome and scoliosis (0.72%) in Type 2, encephalocele and acquired hydrocephalus (11.45%) in Type 3, and reduction deformity of the brain with acquired hydrocephalus (15.95%) in Type 4. Chiari malformations have strong associations with other abnormalities outside of known relationships in the current classification. While neurologic abnormalities are most common, additional body systems are frequently involved especially with worsening hindbrain defects.

Background/UNASSIGNED:Risk of death is important in counseling patients and improving quality of care. Incidence of death in cervical surgery is not firmly established due to its rarity and limited sample sizes, particularly in the context of different surgeries, demographics, and risk factors. Particularly, different patient risk profiles may have varying degrees of risk in terms of surgeries, comorbidities, and demographics. This study aims to use a large patient cohort available on a national database to study the prevalence of death associated with cervical spine surgery. Methods/UNASSIGNED:< .05 differences relative to overall cohort. Results/UNASSIGNED:< .001. Conclusion/UNASSIGNED:In 342 477 cervical spine surgery patients an overall mortality rate of 0.32% was reported. The rate was 3.91% in a cohort of 5933 patients with congestive heart failure and 3.79% in a cohort of 6947 patients with paraplegia. These findings are consistent with previous estimates and may help counsel patients and improve in-hospital safety. Level of Evidence/UNASSIGNED:3.

Background/UNASSIGNED:Effects of nonoperative treatments on surgical outcomes for patients who failed conservative management for cervical spine pathologies remain unknown. The objective is to describe conservative modality use in patients indicated for surgery for degenerative cervical spine conditions and its impact on perioperative outcomes. Methods/UNASSIGNED:tests were performed to determine differences between groups and impact on outcomes. Results/UNASSIGNED: < .05). Conclusions/UNASSIGNED:Radiculopathy patients receiving epidurals returned to work after 1 year more frequently. PT was associated with shorter hospitalizations, greater SF-36 bodily pain norm and physical component score improvements, and increased return-to-work rates after 1 and 2 years. No statistically significant nonoperative treatment was associated with return-to-work rate in myelopathy patients. Clinical Relevance/UNASSIGNED:These findings suggest certain preoperative conservative treatment modalities are associated with improved outcomes in radiculopathy patients.

Background/UNASSIGNED:Factors that are relevant to the decision regarding the use of surgical treatment for degenerative spondylolisthesis include disease-state severity and patient quality-of-life expectations. Some factors may not be easily appraised by the surgeon. In prospective trials involving patients undergoing nonoperative and operative treatment, there are instances of crossover in which patients from the nonoperative group undergo surgery. Identifying and understanding patient characteristics that may influence crossover from nonoperative to operative treatment will aid understanding of what motivates patients toward pursuing surgery. Methods/UNASSIGNED:Patients with degenerative spondylolisthesis who were randomized to nonoperative care in a prospective, multicenter study were evaluated over 8 years of enrollment. Two cohorts were defined: (1) the surgery cohort (patients who underwent surgery at any point) and (2) the nonoperative cohort (patients who did not undergo surgery). A Cox proportional hazards model, modeling time to surgery, was used to explore demographic data, clinical diagnoses, and patient expectations and attitudes after adjusting for other variables. A subanalysis was performed on surgery within 6 months after enrollment and surgery >6 months after enrollment. Results/UNASSIGNED:One hundred and forty-five patients who had been randomized to nonoperative treatment, 80 of whom crossed over to surgery, were included. In analyzing baseline differences between the 2 cohorts, patients who underwent surgery were younger; however, there were no significant difference between the cohorts in terms of race, sex, or comorbidities. Treatment preference, greater Oswestry Disability Index score, marital status, and no joint problems were predictors of crossover to surgery. Clinical factors, including stenosis, neurological deficits, and listhesis levels, did not show a significant relationship with crossover. At the time of long-term follow-up, the surgery cohort showed significantly greater long-term improvement in health-related quality of life (p < 0.001). The difference was maintained throughout follow-up. Conclusions/UNASSIGNED:Neurological symptoms and diagnoses, including listhesis and stenosis severity, did not predict crossover from nonoperative care to surgery. Attitudes toward surgery, greater Oswestry Disability Index score, marital status, and no joint problems were independent predictors of crossover from nonoperative to operative care. Certain demographic characteristics were associated with higher rates of crossover, although they were connected to patient attitudes toward surgery. Level of Evidence/UNASSIGNED:Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND CONTEXT/BACKGROUND:Cost-utility analysis, a special case of cost-effectiveness analysis, estimates the ratio between the cost of an intervention to the benefit it produces in number of quality-adjusted life years. Cervical deformity correction has not been evaluated in terms of cost-utility and in the context of value-based health care. Our objective, therefore, was to determine the cost-utility ratio of cervical deformity correction. STUDY DESIGN/METHODS:This is a retrospective review of a prospective, multicenter cervical deformity database. Patients with 1-year follow-up after surgical correction for cervical deformity were included. Cervical deformity was defined as the presence of at least one of the following: kyphosis (C2-C7 Cobb angle >10°), cervical scoliosis (coronal Cobb angle >10°), positive cervical sagittal malalignment (C2-C7 sagittal vertical axis >4 cm or T1-C6 >10°), or horizontal gaze impairment (chin-brow vertical angle >25°). Quality-adjusted life years were calculated by both EuroQol 5D (EQ5D) quality of life and Neck Disability Index (NDI) mapped to short form six dimensions (SF6D) index. Costs were assigned using Medicare 1-year average reimbursement for: 9+ level posterior fusions (PF), 4-8 level PF, 4-8 level PF with anterior fusion (AF), 2-3 level PF with AF, 4-8 level AF, and 4-8 level posterior refusion. Reoperations and deaths were added to cost and subtracted from utility, respectively. Quality-adjusted life year per dollar spent was calculated using standardized methodology at 1-year time point and subsequent time points relying on maintenance of 1-year utility. RESULTS:Eighty-four patients (average age: 61.2 years, 60% female, body mass index [BMI]: 30.1) were analyzed after cervical deformity correction (average levels fused: 7.2, osteotomy used: 50%). Costs associated with index procedures were 9+ level PF ($76,617), 4-8 level PF ($40,596), 4-8 level PF with AF ($67,098), 4-8 level AF ($31,392), and 4-8 level posterior refusion ($35,371). Average 1-year reimbursement of surgery was $55,097 at 1 year with eight revisions and three deaths accounted for. Cost per quality-adjusted life year (QALY) gained to 1-year follow-up was $646,958 by EQ5D and $477,316 by NDI SF6D. If 1-year benefit is sustained, upper threshold of cost-effectiveness is reached 3-4.5 years after intervention. CONCLUSIONS:Medicare 1-year average reimbursement compared with 1-year QALYdescribed $646,958 by EQ5D and $477,316 by NDI SF6D. Cervical deformity surgeries reach accepted cost-effectiveness thresholds when benefit is sustained 3-4.5 years. Longer follow-up is needed for a more definitive cost-analysis, but these data are an important first step in justifying cost-utility ratio for cervical deformity correction.

Study Design/UNASSIGNED:Prospective cohort study. Objectives/UNASSIGNED:To describe the rate of short-term complications following the posterior use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in cervical deformity (CD) surgery. Methods/UNASSIGNED:CD patients from 2013 to 2015 were enrolled in a prospective, multicenter database. Patients were divided into those receiving rhBMP-2 (BMP) and no rhBMP-2 (NOBMP). The relationship between BMP use, demographic variables surgical variables, radiographic parameters and complications was evaluated. Results/UNASSIGNED:= 0.09, 0.08, 0.06) between the use of BMP and complications (major or operative). Conclusions/UNASSIGNED:BMP use was not directly associated with an increased incidence of early complications in this prospective cohort of operative adult CD patients. Its use was associated with increased number of levels instrumented and fused.

Introduction/UNASSIGNED:Early Onset and Adolescent Idiopathic Scoliosis, relatively common diagnoses (∼3% general population), have been associated with developmental dysplasia of the hip (DDH); a more rare spectrum of anomalies related to the abnormal development of acetabulum, proximal femur, and hip joint. To the best of our knowledge, no high powered investigations have been performed in an attempt to assess incidence and associated risks of DDH in scoliosis patients. Methods/UNASSIGNED:The KID database was queried for ICD-9 codes from 2003 to 2012 pertaining to EOS (Congenital and Idiopathic <10y/o) and AIS patients. Descriptive analysis assessed patient demographics and yearly trends in hip dysplasia rates. EOS and AIS patients with hip dysplasia were isolated, and incidence of hospital admissions for associated anomalies (osteonecrosis, osteoarthritis, recurrent hip dislocation, hip ankylosis) and hip arthroplasty (total + partial) were investigated. Univariate analysis of hip pathology determined significant predictors of hip arthroplasty. Binary logistic regression analysis was used to determine the relationship between these predictors. Results/UNASSIGNED:111,827 scoliosis patients (EOS: 25,747; AIS: 77,183) were included. AIS patients were older (15.2 vs 4.3), more female (64.2% vs 52.1%), had a higher CCI (0.84 vs 0.64), and less racially diverse (all p < 0.001). The incidence of hip dysplasia was 1.4% for AIS patients and 3.9% for EOS patients (p < 0.001). Of the AIS (n = 1073) and EOS (n = 1005) patients with hip dysplasia, 0.3% (p > 0.05 between groups) developed hip osteonecrosis, 0% of patients were coded as having a hip labral tear, hip ankylosis, and 0.6% (EOS: 0.2%; AIS: 0.9%, p = 0.025) developed hip osteoarthritis. AIS patients were more likely to have recurrent hip dislocations (35.4% vs 17.0%, p < 0.001), and both groups had similar primary hip arthroplasty rates (6.7% vs 5.4%, p = 0.118) and revision hip arthroplasty rates (0% vs 0.4%, p = 0.053). Hip osteoarthritis (OR: 13.43[5.21-34.66], p=<0.001) and older age (OR: 1.039[1.007-1.073], p = 0.017) were the only significant predictors of hip arthroplasty (p=<.001). Conclusions/UNASSIGNED:The incidence of hip dysplasia in EOS and AIS populations is higher than that of the general population. The rate of DDH was 3.9% and 1.8% for EOS and AIS, respectively. While the incidence of DDH is higher, associated anomalies of osteoarthritis, osteonecrosis, labral tears, and ankylosis appear to be a minimal risk for AIS and EOS patients with Hip Dysplasia.

STUDY DESIGN/METHODS:Retrospective radiographic review. OBJECTIVES/OBJECTIVE:To understand the effect of variability in sacral endplate selection in transitional lumbosacral vertebrae (TLSV) and its impact on pelvic, regional, and global spinal alignment parameters. BACKGROUND:TLSV can have the characteristics of both lumbar and sacral vertebrae. Difficulties in identification of the S1 endplate may come from nomenclature, number of lumbar vertebrae, sacra, and morphology and may influence the interpretation and consistency of spinal alignment parameters. METHODS:Patients with TLSV were identified and radiographic measurements including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), sagittal vertical axis (SVA), T1-pelvic angle (TPA), pelvic incidence-lumbar lordosis (PI-LL) mismatch, thoracic kyphosis (TK), and spinal inclination (T1SPi) were obtained. Radiographic measurements were performed twice with the sacral endplate at the cephalad and caudal options. Paired t tests assessed the difference between different selection groups. RESULTS:Of 1,869 patients, 70 (3.7%) were found to have TLSV on radiographic imaging. Fifty-eight (82.9%) had lumbarized sacral segments whereas 12 (17.1%) had sacralized lumbar segments. T1-SPi (mean: -1.77°) and TK (mean: 34.86°) did not vary from altering sacral endplate selection. Selection of the caudal TLSV as the sacral endplate resulted in an increase in all pelvic parameters (PI: 66.8° vs. 44.3°, PT: 25.1° vs. 12.7°, and SS: 41.6° vs. 31.6°), regional lumbar parameters (LL: -54.1° vs. 44.0°, PI-LL: 12.7° vs. 0.3°), and global parameters (SVA: 46.1 mm vs. 28.3 mm, TPA: 23.3° vs. 10.8°) as compared to selecting the cephalad TLSV. All mean differences between radiographic parameters were found to be statistically significant (p < .001). CONCLUSIONS:Variation in sacral endplate selection in TLSV significantly affects spinal alignment parameter measurements. A standardized method for measuring TLSV is needed to reduce measurement error and ultimately allow more accurate understanding of alignment targets in patients with TLSV. LEVEL OF EVIDENCE/METHODS:Level III.

STUDY DESIGN/METHODS:Retrospective analysis. OBJECTIVE:To define thoracic compensation and investigate its association with postoperative reciprocal thoracic kyphosis and proximal junctional kyphosis (PJK) SUMMARY OF BACKGROUND DATA.: Adult spinal deformity (ASD) patients recruit compensatory mechanisms like pelvic retroversion and knee flexion. However, thoracic hypokyphosis is a less recognized compensatory mechanism. METHODS:Patients enrolled in a multicenter ASD registry undergoing fusions to the pelvis with UIV between T9-L1 were included. Patients were divided into those with postoperative reciprocal thoracic kyphosis (RK: change in unfused TK ≥15°) with and without PJK and those who maintained thoracic alignment (MT). Thoracic compensation was defined as expected thoracic kyphosis (eTK) minus preoperative TK. RESULTS:For RK (n = 117), the mean change in unfused TK was 21.7° vs 6.1° for MT (n = 102) and the mean PJK angle change was 17.6° vs 5.7° for MT (all p < 0.001). RK and MT were similar in age, BMI, gender, and comorbidities. RK had larger preoperative PI-LL mismatch (30.7 vs. 23.6 p = 0.008) and less preoperative TK (22.3 vs. 30.6 p < 0.001), otherwise SVA, PT and TPA were similar. RK patients had more preoperative thoracic compensation (29.9 vs. 20.0, p < 0.001), more PI-LL correction (29.8 vs. 17.3, p < 0.001) and higher rates of PJK (66% vs. 19%, p < 0.001). There were no differences in preoperative HRQOL except RK had worse SRS appearance (2.2 vs. 2.5, p = 0.005). Using a logistic regression model, the only predictor for postoperative reciprocal thoracic kyphosis was more preoperative thoracic compensation. Postoperatively the RK and MT groups were well aligned. Both younger and older (>65y) RK patients had greater thoracic compensation than MT counterparts. The eTK was not significantly different from the postoperative TK for the RK group without PJK (p = 0.566). CONCLUSIONS:The presence of thoracic compensation in adult spinal deformity is the primary determinant of postoperative reciprocal thoracic kyphosis and these patients have higher rates of proximal junctional kyphosis. LEVEL OF EVIDENCE/METHODS:3.