Faculty Bibliography

PURPOSE/OBJECTIVE:Sagittal spinal deformity (SSD) patients utilize pelvic tilt (PT) and their lower extremities in order to compensate for malalignment. This study examines the effect of hip osteoarthritis (OA) on compensatory mechanisms in SSD patients. METHODS:Patients ≥ 18 years with SSD were included for analysis. Spinopelvic, lower extremity, and cervical alignment were assessed on standing full-body stereoradiographs. Hip OA severity was graded by Kellgren-Lawrence scale (0-4). Patients were categorized as limited osteoarthritis (LOA: grade 0-2) and severe osteoarthritis (SOA: grade 3-4). Patients were matched for age and T1-pelvic angle (TPA). Spinopelvic [sagittal vertical axis (SVA), T1-pelvic angle, thoracic kyphosis (TK), pelvic tilt (PT), lumbar lordosis (LL), pelvic incidence minus lumbar lordosis (PI-LL), T1-spinopelvic inclination (T1SPi)] and lower extremity parameters [sacrofemoral angle, knee angle, ankle angle, posterior pelvic shift (P. Shift), global sagittal axis (GSA)] were compared between groups using independent sample t test. RESULTS:136 patients (LOA = 68, SOA = 68) were included in the study. SOA had less pelvic tilt (p = 0.011), thoracic kyphosis (p = 0.007), and higher SVA and T1Spi (p < 0.001) than LOA. SOA had lower sacrofemoral angle (p < 0.001) and ankle angle (p = 0.043), increased P. Shift (p < 0.001) and increased GSA (p < 0.001) compared to LOA. There were no differences in PI-LL, LL, knee angle, or cervical alignment (p > 0.05). CONCLUSIONS:Patients with coexisting spinal malalignment and SOA compensate by pelvic shift and thoracic hypokyphosis rather than PT, likely as a result of limited hip extension secondary to SOA. As a result, SOA had worse global sagittal alignment than their LOA counterparts. These slides can be retrieved under Electronic Supplementary Material.

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/objectives: Diagnosis and treatment of patients with coexisting hip and spine pathologies can be challenging. Patients with sagittal spinopelvic deformity utilize pelvic tilt (PT) and their lower extremities in order to compensate for malalignment. In patients with lower extremity osteoarthritis (OA), these compensatory mechanisms can be compromised, leading to further disability. Methods: Patients > 18 years with SSD [SVA > 50mm, PT > 25degree, or TK > 60degree] were included for analysis. Spinopelvic, lower extremity, and cervical alignment were assessed on standing full-body stereoradiographs. Hip OA severity was graded by Kellgren-Lawrence scale (0-4). Propensity score matching was used to control for age and T1 pelvic angle (TPA). Patients were categorized as limited OA (LOA: grade 0-2) and severe OA (SOA: grade 3-4). Results: A total of 997 patients (LOA=929, SOA=68) were identified meeting inclusion criteria. After PSM, 136 patients (SOA: n=68, LOA n=68) were included in the study. SOA had less PT (17.8degree+/-12.6degree vs 22.6degree+/-8.4degree, p=0.011), TK (42.5degree+/-21.2degree vs 52.3degree+/-20.2degree, p=0.007), higher SVA (71.6 mm+/-47.1 vs 40.7 mm+/-43.9, p<0.001) and T1Spi (+2.3degree+/-6.4degree vs -2.6degree+/-5.5degree, p<0.001) than LOA. SOA also had a lower SFA (194.3degree+/-12.4degree vs 202.4degree+/-9.5degree, p<0.001) and AA (5.9degree+/-3.5degree vs 7.2degree+/-3.6degree, p=0.043), increased P.Shift (49.7mm+/-39.5 vs 19.7mm+/-28.4; p<0.001) and increased GSA (7.7degree+/-4.5degree vs 5.0degree+/-4.0degree, p< 0.001) compared to LOA. There was no difference in PI, PI-LL mismatch, LL, KA or cervical alignment (p >0.05). Conclusion: Patients with coexisting spinal malalignment and severe hip OA compensate by pelvic shift and thoracic hypokyphosis rather than pelvic tilt, likely as a result of limited hip extension

OBJECTIVE: The aim of this study is to present our technique for a large focal correction of a partially flexible dropped head deformity through combined anterior and posterior osteotomies, as well as anterior soft tissue releases. METHODS: One patient with dropped head deformity underwent an anterior and posterior osteotomy with anterior soft tissue release. RESULTS: The patient recovered well, with postoperative radiographs demonstrating significant improvement in coronal and sagittal alignment. His C2-C7 sagittal vertical axis improved from 7.5 cm preoperatively to less than 4 cm postoperatively and his C2-C7 sagittal Cobb improved from 35 degrees of kyphosis to 10 degrees of lordosis. CONCLUSION: In this report, we present our technique for a large focal correction of a partially flexible dropped head deformity through combined anterior and posterior osteotomies and anterior soft tissue releases. These more conservative osteotomies permitted gradual deformity correction and alleviated the need for pedicle subtraction osteotomy. We were able to restore horizontal gaze and improve sagittal malalignment. Although the technique we present here is one of many possible options for managing the deformity, we believe this combined approach is safe and effective and well tolerated by patients.

OBJECTIVE Verifying the adequacy of surgical correction of adult spinal sagittal deformity (SSD) leads to improved postoperative alignment and clinical outcomes. Traditionally, surgeons relied on intraoperative measurements of lumbar lordosis (LL) correction. However, T-1 pelvic angle (TPA) and its component angles more reliably predict postoperative alignment. While TPA is readily measured on standing radiographs, intraoperative radiographs offer poor resolution of the bicoxofemoral axis. A method to recreate this radiographic landmark by extrapolating preoperative measurements has been described. The authors aimed to assess the reliability of measurements of global spinal alignment obtained via geometrical reconstitution of the bicoxofemoral axis on prone intraoperative radiographs. METHODS A retrospective review was performed. Twenty sets of preoperative standing full-length and intraoperative prone 36-inch lateral radiographs were analyzed. Pelvic incidence (PI) and sacral to bicoxofemoral axis distance (SBFD) were recorded on preoperative films. A perpendicular line was drawn on the intraoperative radiograph from the midpoint of the sacral endplate. This was used as one limb of the PI, and the second limb was digitally drawn at an angle that reproduced the preoperatively obtained PI, extending for a distance that matched the preoperative SBFD. This final point marked the obscured bicoxofemoral axis. These landmarks were used to measure the L-1, T-9, T-4, and T-1 pelvic angles (LPA, T9PA, T4PA, and TPA, respectively) and LL. Two spine fellows and 2 attending spine surgeons made independent measurements and repeated the process in 1 month. Mixed-model 2-way intraclass correlation coefficient (ICC) and Cronbach's α values were calculated to assess interobserver, intraobserver, and scale reliability. RESULTS Interobserver reliability was excellent for preoperative PI and intraoperative LPA, T9PA, and T4PA (ICC = 0.88, 0.84, 0.84, and 0.93, respectively), good for intraoperative TPA (ICC = 0.68), and fair for preoperative SBFD (ICC = 0.60) and intraoperative LL (ICC = 0.50). Cronbach's α was ≥ 0.80 for all measurements. Measuring PI on preoperative standing images had excellent intraobserver reliability for all raters (ICC = 0.89, range 0.80-0.93). All raters but one showed excellent reliability for measuring the SBFD. Reliability for measuring prone LL was good for all raters (ICC = 0.71, range 0.64-0.76). The LPA demonstrated good to excellent reliability for each rater (ICC = 0.76, range 0.65-0.81). The thoracic pelvic angles tended to be more reliable at more distal vertebrae (T9PA ICC = 0.71, range 0.49-0.81; T4PA ICC = 0.62, range 0.43-0.83; TPA ICC = 0.56, range 0.31-0.86). CONCLUSIONS Intraoperative assessment of global spinal alignment with TPA and component angles is more reliable than intraoperative measurements of LL. Reconstruction of preoperatively measured PI and SBFD on intraoperative radiographs effectively overcomes poor visualization of the bicoxofemoral axis. This method is easily adopted and produces accurate and reliable prone intraoperative measures of global spinal alignment.

STUDY DESIGN/METHODS:Retrospective review. OBJECTIVE:Determine whether alignment or myelopathy improvement drives patient outcomes after cervical deformity (CD) corrective surgery. SUMMARY OF BACKGROUND DATA/BACKGROUND:CD correction involves radiographic malalignment correction and procedures to improve motor function and pain. It is unknown whether alignment or myelopathy improvement drives patient outcomes. METHODS:Inclusion: Patients with CD with baseline/1-year radiographic and outcome scores. Cervical alignment improvement was defined by improvement in Ames CD modifiers. modified Japanese Orthopaedic Association (mJOA) improvement was defined as mild [15-17], moderate [12-14], severe [<12]. Patient groups included those who only improved in alignment, those who only improved in mJOA, those who improved in both, and those who did not improve. Changes in quality-of-life scores (neck disability index [NDI], EuroQuol-5 dimensions [EQ-5D], mJOA) were evaluated between groups. RESULTS:A total of 70 patients (62 yr, 51% F) were included. Overall preoperative mJOA score was 13.04 ± 2.35. At baseline, 21 (30%) patients had mild myelopathy, 33 (47%) moderate, and 16 (23%) severe. Out of 70 patients 30 (44%) improved in mJOA and 13 (18.6%) met 1-year mJOA minimal clinically important difference. Distribution of improvement groups: 16/70 (23%) alignment-only improvement, 13 (19%) myelopathy-only improvement, 18 (26%) alignment and myelopathy improvement, and 23 (33%) no improvement. EQ-5D improved in 11 of 16 (69%) alignment-only patients, 11 of 18 (61%) myelopathy/alignment improvement, 13 of 13 (100%) myelopathy-only, and 10 of 23 (44%) no myelopathy/alignment improvement. There were no differences in decompression, baseline alignment, mJOA, EQ-5D, or NDI between groups. Patients who improved only in myelopathy showed significant differences in baseline-1Y EQ-5D (baseline: 0.74, 1 yr:0.83, P < 0.001). One-year C2-S1 sagittal vertical axis (SVA; mJOA r = -0.424, P = 0.002; EQ-5D r = -0.261, P = 0.050; NDI r = 0.321, P = 0.015) and C7-S1 SVA (mJOA r = -0.494, P < 0.001; EQ-5D r = -0.284, P = 0.031; NDI r = 0.334, P = 0.010) were correlated with improvement in health-related qualities of life. CONCLUSION/CONCLUSIONS:After CD-corrective surgery, improvements in myelopathy symptoms and functional score were associated with superior 1-year patient-reported outcomes. Although there were no relationships between cervical-specific sagittal parameters and patient outcomes, global parameters of C2-S1 SVA and C7-S1 SVA showed significant correlations with overall 1-year mJOA, EQ-5D, and NDI. These results highlight myelopathy improvement as a key driver of patient-reported outcomes, and confirm the importance of sagittal alignment in patients with CD. LEVEL OF EVIDENCE/METHODS:3.

STUDY DESIGN/METHODS:Retrospective review of prospective multicenter adult spinal deformity (ASD) database. OBJECTIVE:To create a model based on baseline demographic, radiographic, health-related quality of life (HRQOL), and surgical factors that can predict patients meeting the Oswestry Disability Index (ODI) minimal clinically important difference (MCID) at the two-year postoperative follow-up. SUMMARY OF BACKGROUND DATA/BACKGROUND:Surgical correction of ASD can result in significant improvement in disability as measured by ODI, with the goal of reaching at least one MCID. However, a predictive model for reaching MCID following ASD correction does not exist. METHODS:ASD patients ≥18 years and baseline ODI ≥ 30 were included. Initial training of the model comprised forty-three variables including demographic data, comorbidities, modifiable surgical variables, baseline HRQOL, and coronal/sagittal radiographic parameters. Patients were grouped by whether or not they reached at least one ODI MCID at two-year follow-up. Decision trees were constructed using the C5.0 algorithm with five different bootstrapped models. Internal validation was accomplished via a 70:30 data split for training and testing each model, respectively. Final predictions from the models were chosen by voting with random selection for tied votes. Overall accuracy, and the area under a receiver operating characteristic curve (AUC) were calculated. RESULTS:198 patients were included (MCID: 109, No-MCID: 89). Overall model accuracy was 86.0%, with an AUC of 0.94. The top 11 predictors of reaching MCID were gender, Scoliosis Research Society (SRS) activity subscore, back pain, sagittal vertical axis (SVA), pelvic incidence-lumbar lordosis mismatch (PI-LL), primary version revision, T1 spinopelvic inclination angle (T1SPI), American Society of Anesthesiologists (ASA) grade, T1 pelvic angle (T1PA), SRS pain, SRS total. CONCLUSIONS:A successful model was built predicting ODI MCID. Most important predictors were not modifiable surgical parameters, indicating that baseline clinical and radiographic status is a critical factor for reaching ODI MCID. LEVEL OF EVIDENCE/METHODS:Level II.

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.

Background: Recent studies suggest non-routine discharge, includingdischarge to inpatient rehab and skilled nursing facilities, is associatedwith increased cost of care. Given the rising prevalence of cervicaldeformity (CD)-corrective surgery and the necessity of value-basedhealthcare, it is important to identify indicators for non-routine discharge in surgical CD patients.Study Design: Retrospective review of prospective, multicenter CDdatabase.Methods: Included: Surgical CD patients (C2-C7 Cobb [10,CL [10, cSVA [4 cm, or CBVA [25) [18 years with discharge and baseline (BL) radiographic data. Non-routine dischargedefined: inpatient rehab or skilled nursing facility. ConditionalInference Decision Trees identified predictors of non-routine discharge, and cut-off points at which predictors have a global effect.A Conditional Variable Importance Table used non-replacementsampling set of 3000 Conditional Inference trees to identify influential patient/surgical factors. Binary logistic regression indicated effectsize of influential factors at significant cut-off points. Means comparison testing assessed the relationship between non-routinedischarge and reop/HRQL outcomes.Results: Included: 138 patients (61 +/- 10 years, 63%F) undergoingCD-corrective surgery (8.2 +/- 4.6 levels; 49% posterior-onlyapproach, 16% anterior-only, 35% combined). 29% of patientsexperienced non-routine discharge (21% inpatient rehab, 8% SNF).BL cervical and upper-cervical malalignment was the strongest predictor of non-routine discharge: [1] C1 slope [14 (OR:8.4 [95%CI:3.1-22.7]), [3] C2 slope [57 (OR: 7.0 [2.6-18.3]), [4] TSCL [57 (OR: 5.9 [2.2-15.9]), [14] C0 slope[-0.66 (OR: 4.2[1.9-9.3]), [15] cSVA [40 mm (OR: 4.6 [2.0-10.9]), [18] McGregor's slope [1.9 (OR: 4.1 [1.7-9.9]). Patient-related predictors ofnon-routine discharge were [2] BL gait impairment (OR: 5.29[2.3-12.4]), [8] age [59 years (OR: 4.3 [1.6-11.1]), [10] apex of CDprimary driver [C7 (OR: 3.9[1.8-8.6]), and [13] admission tosurgical ICU (OR: 5.4 [1.9-14.8]). Experiencing 2 or more complications was predictive of non-routine discharge (OR: 4.2 [1.9-9.2]),but the only specific complications predictive of non-routone discharge were EBL [900 cc (OR: 3.6 [1.7-7.7]) and presence of anyneuro complication (OR: 2.8 [1.8-8.4]). The only surgical predictor ofnon-home discharge was [12] fusion[8 levels (OR: 4.0 [1.8-9.0]).LOS [6 days was also predictive of non-routone discharge (OR: 4.0[1.8-8.9]). There was no relationship between non-routine dischargeand reop within 3 months (P = 0.249), 6 months (P = 0.793), or1 year (P = 0.814) of index procedure. Despite no differences in BLEQ-5D (P = 0.946), non-routine patients had inferior 1-year postopEQ-5D scores (non-routine: 0.75, home: 0.79, P = 0.044).Conclusions: Preop cervical malalignment was a top predictor ofnon-routine discharge in surgical CD patients. Age, driver of deformity, and [8 level fusion also predicted non-routine discharge, andshould be taken into account to improve resource allocation andpatient counseling