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Background: Although rare, minimally invasive spine techniques do have the risk of intraoperative device failure. Kirschner wire (K-wire) fractures during minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) have not been previously reported. This report focuses on the incidence of k-wire fractures following MI-TLIF and describes techniques to help avoid and treat these fractures when they occur. Methods: Inclusion criteria: (i) patients underwent 1, 2, or 3 level MI-TLIF over a 10-year period and (ii) had a k-wire fracture leading to a retained fragment. Exclusion criteria included: >10° coronal curves, significant sagittal malalignment, infection, and preoperative instrumentation failure. Results: Of 513 patients undergoing MI-TLIF, 6 (1.2%) sustained k-wire fracture (3 males, 3 females, mean age 43 ± 13 years). Complications included k-wire fracture alone (4 patients), cerebrospinal fluid (CSF) leak (1 patient), and both ileus and revision for hardware removal (1 patient). All six patients went home postoperatively. The mean follow-up duration was 27.7 ± 37.4 months. All retained k-wire fragments were located in the vertebral bodies at the tip of the pedicle screws; none breached the anterior cortex of the vertebral bodies. None of the k-wires migrated at final follow-up 7.8 years (93.7 months) postoperatively. Furthermore, no complications were attributed to retained k-wires. Conclusions: K-wire fractures during MI-TLIF are rare (incidence of 1.2%) and retained k-wire segments led to no postoperative complications (e.g. no migration). [ABSTRACT FROM AUTHOR]

Objective. To evaluate factors associated with the long-term durability of cost-effectiveness (CE) in ASD patients. Background. A substantial increase in costs associated with the surgical treatment for adult spinal deformity (ASD) has given precedence to scrutinize the value and utility it provides. Methods. We included 327 operative ASD patients with five-year (5 yr) follow-up. Published methods were used to determine costs based on CMS.gov definitions and were based on the average DRG reimbursement rates. The utility was calculated using quality-adjusted life-years (QALY) utilizing the Oswestry Disability Index (ODI) converted to Short-Form Six-Dimension (SF-6D), with a 3% discount applied for its decline in life expectancy. The CE threshold of $150,000 was used for primary analysis. Results. Major and minor complication rates were 11% and 47%, respectively, with 26% undergoing reoperation by five years. The mean cost associated with surgery was $91,095 ± $47,003, with a utility gain of 0.091 ±0.086 at one years, QALY gained at 2 years of 0.171± 0.183, and at five years of 0.42 ±0.43. The cost per QALY at two years was $414,885, which decreased to $142,058 at five years. With the threshold of $150,000 for CE, 19% met CE at two years and 56% at five years. In those in which revision was avoided, 87% met cumulative CE till life expectancy. Controlling analysis depicted higher baseline CCI and pelvic tilt (PT) to be the strongest predictors for not maintaining durable CE to five years [CCI OR: 1.821 (1.159--2.862), P=0.009] [PT OR: 1.079 (1.007--1.155), P=0.030]. Conclusions. Most patients achieved cost-effectiveness after four years postoperatively, with 56% meeting at five years postoperatively. When revision was avoided, 87% of patients met cumulative cost-effectiveness till life expectancy. Mechanical complications were predictive of failure to achieve cost-effectiveness at two years, while comorbidity burden and medical complications were at five years. [ABSTRACT FROM AUTHOR]

Background Length of stay (LOS) after surgery for adult spinal deformity (ASD) is a critical period that allows for optimal recovery. Predictive models that estimate LOS allow for stratification of high-risk patients. Methods A prospectively acquired multicenter database of patients with ASD was used. Patients with staged surgery or LOS >30 days were excluded. Univariable predictor importance ≥0.90, redundancy, and collinearity testing were used to identify variables for model building. A generalized linear model was constructed using a training dataset developed from a bootstrap sample; patients not randomly selected for the bootstrap sample were selected to the training dataset. LOS predictions were compared with actual LOS to calculate an accuracy percentage. Results Inclusion criteria were met by 653 patients. The mean LOS was 7.9 ± 4.1 days (median 7 days; range, 1–28 days). Following bootstrapping, 893 patients were modeled (653 in the training model and 240 in the testing model). Linear correlations for the training and testing datasets were 0.632 and 0.507, respectively. The prediction accuracy within 2 days of actual LOS was 75.4%. Conclusions Our model successfully predicted LOS after ASD surgery with an accuracy of 75% within 2 days. Factors relating to actual LOS, such as rehabilitation bed availability and social support resources, are not captured in large prospective datasets. Predictive analytics will play an increasing role in the future of ASD surgery, and future models will seek to improve the accuracy of these tools. [ABSTRACT FROM AUTHOR]

Background: Height gain following a surgical procedure for patients with adult spinal deformity (ASD) is incompletely understood, and it is unknown if height gain correlates with patient-reported outcome measures (PROMs). Methods: This was a retrospective cohort study of patients undergoing ASD surgery. Patients with baseline, 6-week, and subanalysis of 1-year postoperative full-body radiographic and PROM data were examined. Correlation analysis examined relationships between vertical height differences and PROMs. Regression analysis was utilized to preoperatively estimate T1-S1 and S1-ankle height changes. Results: This study included 198 patients (mean age, 57 years; 69% female); 147 patients (74%) gained height. Patients with height loss, compared with those who gained height, experienced greater increases in thoracolumbar kyphosis (2.81° compared with 27.37°; p < 0.001) and thoracic kyphosis (12.96° compared with 4.42°;p = 0.003). For patients with height gain, sagittal and coronal alignment improved from baseline to postoperatively: 25° to 21° for pelvic tilt (PT), 14° to 3° for pelvic incidence 2 lumbar lordosis (PI-LL), and 60 mm to 17 mm for sagittal vertical axis (SVA) (all p < 0.001). The full-body mean height gain was 7.6 cm, distributed as follows: sella turcica-C2, 2.9 mm; C2-T1,2.8mm;T1-S1(trunkgain),3.8cm;andS1-ankle(lower-extremitygain),3.3cm(p<0.001).T1-S1heightgain correlated with the thoracic Cobb angle correction and the maximum Cobb angle correction (p = 0.002). S1-ankle height gain correlated with the corrections in PT, PI-LL, and SVA (p < 0.001). T1-ankle height gain correlated with the corrections in PT (p < 0.001) and SVA (p = 0.03). Trunk height gain correlated with improved Scoliosis Research Society (SRS-22r) Appearance scores (r = 0.20; p = 0.02). Patient-Reported Outcomes Measurement Information System (PROMIS) Depression scores correlated with S1-ankle height gain (r = 20.19; p = 0.03) and C2-T1 height gain (r = 20.18; p = 0.04). A 1° correction in a thoracic scoliosis Cobb angle corresponded to a 0.2-mm height gain, and a 1° correction in a thoracolumbar scoliosis Cobb angle resulted in a 0.25-mm height gain. A 1° improvement in PI-LL resulted in a 0.2-mm height gain. Conclusions: Most patients undergoing ASD surgery experienced height gain following deformity correction, with amean full-body height gain of 7.6 cm. Height gain can be estimated preoperatively with predictive ratios, and height gain was correlated with improvements in reported SRS-22r appearance and PROMIS scores. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: While reimbursement is centered on 90-day outcomes, many patients may still achieve optimal, long-term outcomes following adult spinal deformity (ASD) surgery despite transient short-term complications. Objective: Compare long-term clinical success and cost-utility between patients achieving optimal realignment and suboptimally aligned peers. Study Design/Setting: Retrospective cohort study of a prospectively collected multicenter database. Methods: ASD patients with two-year (2Y) data included. Groups were propensity score matched (PSM) for age, frailty, body mass index (BMI), Charlson Comorbidity Index (CCI), and baseline deformity. Optimal radiographic criteria are defined as meeting low deformity in all three (Scoliosis Research Society) SRS-Schwab parameters or being proportioned in Global Alignment and Proportionality (GAP). Cost-per-QALY was calculated for each time point. Multivariable logistic regression analysis and ANCOVA (analysis of covariance) adjusting for baseline disability and deformity (pelvic incidence (PI), pelvic incidence minus lumbar lordosis (PI-LL)) were used to determine the significance of surgical details, complications, clinical outcomes, and cost-utility. Results: A total of 930 patients were considered. Following PSM, 253 "optimal" (O) and 253 "not optimal" (NO) patients were assessed. The O group underwent more invasive procedures and had more levels fused. Analysis of complications by two years showed that the O group suffered less overall major (38% vs. 52%, p = 0.021) and major mechanical complications (12% vs. 22%, p = 0.002), and less reoperations (23% vs. 33%, p = 0.008). Adjusted analysis revealed O patients more often met MCID (minimal clinically important difference) in SF-36 PCS, SRS-22 Pain, and Appearance. Cost-utility-adjusted analysis determined that the O group generated better cost-utility by one year and maintained lower overall cost and costs per QALY (both p < 0.001) at two years. Conclusions: Fewer late complications (mechanical and reoperations) are seen in optimally aligned patients, leading to better long-term cost-utility overall. Therefore, the current focus on avoiding short-term complications may be counterproductive, as achieving optimal surgical correction is critical for long-term success. [ABSTRACT FROM AUTHOR]

Recent advances in risk stratification have led to improvements in our ability to predict complications, cost and outcomes. Chronological age is important in almost all risk calculators; however, genetic or biological age may be more informative. Several techniques exist to assess genetic age including DNA methylation patterns with epigenetic clocks, telomere length and analysis of both mitochondrial DNA and single nucleotide polymorphisms. Our lab recently demonstrated a novel association between telomere length and 90-day complications in adult deformity surgery. There are no current risk stratification tools that integrate markers of cellular aging or biophysiologic reserve. Determining the optimal aging biomarkers to include in risk assessment models will be critical to future work in preoperative risk assessment. To assess the utility of epigenetic clocks and telomere length in evaluating comorbidity burden, frailty, disability and postoperative complications. Prospective cohort of adult deformity patients performed at a single academic center. Adult patients with spinal deformity undergoing elective surgery. Any medical or surgical complication within 90 days from surgery. Adult spinal deformity patients were prospectively enrolled. Demographics, frailty index (ASD-FI), Charlson comorbidity index (CCI), Oswestry Disability Index (ODI), and whole blood were collected along with presence of any medical or surgical complications at 90 days. CpG methylation was quantified using the Illumina EPIC array platform. Raw methylation data were processed using a custom pipeline in R to extract 7 epigenetic metrics: Horvath Age, Hannum Age, instantaneous pace of aging (DunedinPACE), and 4 principal component (PC) corrected epigenetic age metrics (PC Horvath, PC Hannum, PC PhenoAge, and PC GrimAge). Telomere length was measured directly by qPCR (TSR) or indirectly by methylation-based estimation (PC DNAmTL), which estimates telomere length using specific methylation sequences and correlation to leukocyte telomere length. Linear regression with biweight midcorrelation (bicor) was used to compare continuous variables. Logistic regression with odds radio (OR) was used for complications. Gender and BMI were treated as fixed-effects and added to each model. A total of 43 patients were included with mean age of 65 years and 21 women (49%). A mean of 11 levels were fused posteriorly with 21 combined anterior-posterior approaches (43%) and 18 three-column osteotomies (42%). There were no significant differences in age, gender, BMI, preoperative ASA classification, CCI score, ODI, or surgical variables between patients who had complications compared to those without. CCI correlated with epigenetic age using 6 epigenetic clocks (Hannum Age, Horvath Age, PC Hannum, PC Horvath, PC PhenoAge, PC GrimAge) and estimated telomere length (PC DNAmTL). ASD-FI correlated with epigenetic age using the DunedinPACE epigenetic clock (bicor=0.439, p=0.003). ODI showed a trend toward correlation with epigenetic age using DunedinPACE, but did not meet statistical significance (bicor=0.262, p=0.098). Both direct and indirect telomere measures were associated with 90-day complications (TSR, OR=1,466, p=0.014 and PC DNAmTL, OR=279, p=0.010), while epigenetic age using the PC GrimAge clock showed only a trend (OR=1.09, p=0.067). Epigenetic clocks seem to correlate with comorbidity (CCI) and disease-specific frailty (ASD-FI), while telomere length is significantly associated with complications. Perhaps most importantly, both direct and indirect measures of telomere length showed significant associations with complications, validating both approaches for this application. Integration of biomarkers into current risk calculators has significant potential for improved prediction accuracy, preoperative optimization and tailored surgical planning. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Reports have shown that cell saver salvage (CS) processing introduces fragile RBCs with sublethal injuries to its recipients. In a propensity-score matched analysis, Mohanty et al discerned that a CS to estimated blood loss (EBL) ratio (CS:EBL) ≥0.33 is shown to be associated with higher rates of 30D readmissions. We aim to analyze the effect of this ratio on cardiopulmonary (CP) and renal complications. To determine whether increased CS transfusion to EBL is a driver in the development of cardiopulmonary (CP) and/or renal complications. Prospective, multicenter cohort of ASD pts w/ ≥1 criteria: PI-LL≥25°, TPA≥30°, SVA≥15cm, thoracic scoliosis≥70°, thoracolumbar scoliosis ≥50°, global coronal malalignment≥7cm, and/or undergoing 3CO. A total of 406 adult spinal deformity (ASD) patients who underwent surgery for complex spinal correction and had cell saver salvage transfused intraoperatively. Independent factors associated with the development of CP and/or renal medical complications. Patients were dichotomized based on whether CS:EBL ≥0.33 or < 0.33. Patients were excluded if they had no CS transfused. Key outcomes included renal and CP-related medical complications. Patient characteristics, preoperative labs, operative data, and radiographic parameters were compared using appropriate statistical tests. A conceptual multivariable logistic regression model was built to assess risk factors associated with the primary outcome. A total of 406 patients were included in this analysis with 10.6% (N=43) and 89.4% (N=363) patients having CS:EBL ≥0.33 and < 0.33, respectively. The CS:EBL ≥0.33 patients were older (66.2±12.2yrs vs 58.9±16.4, p=0.0007), experienced less EBL intraoperatively (1048.3±852.2cc vs 1695.6±1295.3cc, p<0.0001), less instrumented levels (TIL) (12.2±3.3 vs 14.1±3.6, p=0.0001), less PCOs performed (72.1% vs 86.8%, p=0.0103) and less major coronal cobb correction (-17.0±14.6 vs -22.7±16.7, p=0.0373). Despite comparable transfusion rates, CS:EBL ≥0.33 patients has lesser pRBC, FFP, and platelet units transfused intraoperatively (p<0.05). No significant differences were observed among overall CP and renal complications. However, when stratifying CP complications by type, CS:EBL ≥0.33 patients experienced a greater rate of pulmonary embolisms (PE) (9.3% vs 1.4%, p=0.0093) within 30D of surgery. A multivariable logistic regression model adjusting for the significant differences between the two groups discerned CS:EBL ≥0.33 to be an independent risk factor for the development of PE, conferring an OR of 6.57 (1.75-24.66) with excellent model diagnostics (Model p-value=0.0031, AUC=0.92, Hosmer and Lemeshow Goodness-of-Fit Test p-value = 0.7264). Patients with a CS:EBL ratio ≥0.33 have a 6.57x greater risk of developing a pulmonary embolisms early postoperatively independent of EBL and transfusions administered. The findings support reevaluation of CS use in this patient population dependent on EBL. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Midthoracic spinal levels (T5 to T8) are rarely chosen as the posterior upper instrumented vertebra (UIV) in spinopelvic fusions for adult spinal deformity (ASD). To compare the rates of complications between spinopelvic fusions with a midthoracic UIV to those with an upper thoracic or lower thoracic UIV. Retrospective analysis of prospectively collected multicenter registry data. All ASD patients with ≥2 years of follow-up in a multicenter registry with a sacropelvic (S1, S2, ilium) lower instrumented vertebra were included. Rates of any complication, surgical complications, and reoperation We used multivariable regression to identify factors associated with selection for an upper-midthoracic UIV (UM UIV, T5 or T6), as opposed to an UT UIV, and selection for a lower-midthoracic UIV (LM UIV, T7 or T8) compared to a LT UIV. Patients with an UM UIV were then matched to patients with a UT UIV, and patients with an LM UIV were matched to patients with an LT UIV, across demographic and spinopelvic parameters. Rates of any complication, surgical complications, and reoperation were compared. Among 1145 patients, 4.6% had a midthoracic UIV. Selection for T5 or T6 UIV, as opposed to T3 or T4, was associated with less T10-L2 kyphosis (p=0.011), greater T4 pelvic angle (p=0.021), smaller L1 pelvic angle (p=0.010). Selection for T7 or T8 UIV, as opposed to T9 or T10, was associated with smaller T1 pelvic angle (p=0.001), greater L1 pelvic angle (p=0.001), greater pelvic tilt (p=0.030), more T10-L2 kyphosis (p=0.002), and less thoracic kyphosis (p=0.018). 25 patients with an UM UIV were matched to 112 patients with a UT UIV, and had the same overall rate of complications (56.0% vs 84.0%, p=0.148), and a lower rate of surgical complications (28.0% vs 72.0%, p=0.005) and reoperation (12.0% vs 44.0%, p=0.047). 24 patients with LM UIV were matched to 108 patients with LT UIV, and had a lower overall rate of complications (37.5% vs 79.2%, p=0.005) and surgical complications (12.5% vs 62.5%, p<0.001), and equal rates of reoperation (4.2% vs 20.8%, p=0.144). In a select subset of ASD patients in which a midthoracic UIV was chosen, complication rates were the same or better than fusions with an upper- or lower-thoracic UIV; however, results are likely limited by selection bias. Although some distinguishing baseline alignment factors were identified in this study, further investigation is warranted. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the impact of the lowest instrumented vertebra (LIV) on Distal Junctional kyphosis (DJK) incidence in adult cervical deformity (ACD) surgery. Methods: Prospectively collected data from ACD patients undergoing posterior or anterior–posterior reconstruction at 13 US sites was reviewed up to 2-years postoperatively (n = 140). Data was stratified into five groups by level of LIV: C6-C7, T1-T2, T3-Apex, Apex-T10, and T11-L2. DJK was defined as a kyphotic increase > 10° in Cobb angle from LIV to LIV-1. Analysis included DJK-free survival, covariate-controlled cox regression, and DJK incidence at 1-year follow-up. Results: 25/27 cases of DJK developed within 1-year post-op. In patients with a minimum follow-up of 1-year (n = 102), the incidence of DJK by level of LIV was: C6-7 (3/12, 25.00%), T1-T2 (3/29, 10.34%), T3-Apex (7/41, 17.07%), Apex-T10 (8/11, 72.73%), and T11-L2 (4/8, 50.00%) (p < 0.001). DJK incidence was significantly lower in the T1-T2 LIV group (adjusted residual = −2.13), and significantly higher in the Apex-T10 LIV group (adjusted residual = 3.91). In covariate-controlled regression using the T11-L2 LIV group as reference, LIV selected at the T1-T2 level (HR = 0.054, p = 0.008) or T3-Apex level (HR = 0.081, p = 0.010) was associated with significantly lower risk of DJK. However, there was no difference in DJK risk when LIV was selected at the C6-C7 level (HR = 0.239, p = 0.214). Conclusion: DJK risk is lower when the LIV is at the upper thoracic segment than the lower cervical segment. DJK incidence is highest with LIV level in the lower thoracic or thoracolumbar junction. [ABSTRACT FROM AUTHOR]

An accurate knowledge of a patient's risk for IONM cord-level loss prior to deformity correction is important for the informed decision-making process, but no prediction tool currently exists. To utilize machine learning (ML) algorithms to create an accurate scoring system to preoperatively predict cord-level IONM data loss. Retrospective review of single surgeon prospective and consecutively collected patient data. A total of 1,106 spinal deformity patients consisting of 735 and 371 adult and pediatric patients, respectively. To determine preoperative features using ML algorithms to develop a scoring system for predicting IONM spinal cord data loss. In total, 1,106 patients (adult=735, pediatric=371) who had spinal deformity surgery from 2015-2023 were reviewed. This included 205 perioperative variables, such as demographics, diagnosis, medical history, physical exam, operative factors, labs, preoperative/intraoperative x-rays, preop MRI/CT. IONM cord-level data was reviewed with the senior member of the IONM team. A stepwise ML approach using random forest analysis and multivariate logistic regression was performed. Patients were randomly allocated into training (50%) and testing (50%) cohorts. Threshold values for features were calculated from the trained random forest model, and feature scores were derived by rounding up feature weights from the logistic regression model. Variables in the final scoring calculator were selected to optimize predictive performance (accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC)). Analysis was performed using scikit-learn (v.0.24.2) in Python (v.3.9.18). Through the ML process, a total of 7 features were designated to be included in the scoring system: spinal cord shape Type 3 (score=2), conus level below L2 (score=2), preoperative upright largest Cobb angle ≥75° (score=2), upper instrumented vertebra in the cervical spine (score=2), preoperative to intraoperative decrease in hematocrit ≥12 (score=1), total deformity angular ratio (TDAR) ≥25 (score=1), and three column osteotomy (3CO) (score=1). Patients with increasing cumulative scores had dramatically increased rates of IONM cord-level loss, with a cumulative score ≤ 2 having an IONM cord-level loss rate of 0.8% vs score ≥7 rate of 95%. When evaluated on the test cohort, the scoring system achieved an accuracy of 90.3%, sensitivity of 80%, specificity of 91%, and an AUROC of 0.85. This is the first study to provide an ML derived scoring system using perioperative variables which accurately predicted IONM cord-level loss during pediatric and adult spinal deformity surgery with over 90% reliability. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

A relatively small percentage of patients are responsible for a disproportional amount of resource utilization in adult ASD surgery and contribute to significantly elevating the average cost across the surgically treated patients. These patients are called super-utilizers (SU). Modest reduction in the frequency of these super-utilization episodes has the potential to significantly improve the value of ASD surgery. The goal of this study was to determine which, if any, baseline patient, radiographic, and/or surgical factors are the most important drivers of this disproportional increased resource utilization. We hypothesize that baseline patient factors predicts super-utilizers (SU) in adult spinal deformity surgery (ASD) more than surgical or deformity factors. Retrospective Review of a prospective, multicenter registry. A total of 1299 index operative ASD patients eligible for 2-yr follow-up. Predictors of SU vs Non-SU in ASD. A prospective multicenter consecutive series of ASD patients was reviewed. Inclusion criteria was diagnosis of ASD (scoliosis≥20°, C7-SVA≥5cm, PT≥25°, or TK≥60°), >4 level posterior fusion, and minimum 2-year follow-up. Index and total episode of care (EOC) cost in 2022 dollars were calculated using average itemized direct costs obtained from the administrative hospital records for all events in the inpatient EOC. Patients with total 2-year EOC cost greater than 90th percentile were considered SU. Multivariate generalized linear models were used to identify the most significant predictors of SU. A total of 1299 patients were eligible for 2-yr follow-up with mean age 60.0+14.1 years, 76% female, and 93% caucasians. SU patients are marginally older (+2.6 yrs; p=0.03), depressed (34.2% vs 25.8%; p=0.03) and tend to have higher propensity for fraility (p=0.003), comorbidities (0.01), reoperation rates (54.8% vs 17.0%; p<0.001), and LOS (+3 days; p<0.0001) compared to non-SU. While degree of sagittal deformity (Schwab sagittal modifiers, all p>0.05) and proportion of 3-column osteotomies (p>0.05) were similar between the groups, SU patients have higher surgical invasiveness score (+28; p<0.001), more vertebrae fused (+3; p<0.0001); more interbody fusions (80% vs 55%; p<0.0001), more BMP use (87.3% vs 69.4%; p=0.0002); longer OR time (+91 mins; p<0.0001), increased blood loss (+700 mL; p<0.0001), and longer length of stay (+3 days; p<0.0001). Index and EOC cost were 49% (p<0.0001) and 62% (p<0.0001) higher respectively in SU. While cost/QALY was 3-times higher in SU compared to non-SU. Multivariate analysis identified Schwab modifier SVA, surgical invasiveness, OR time, blood loss, BMP use, and LOS as strong predictors of SU (all p<0.01). Surgical invasiveness score greater than 118, being in OR for more than 7.6 hrs, blood loss more than 700 ml, utilizing BMP, and LOS more than 11 days were strong predictors of being a SU. Patients with SVA grade of + and ++ were less likely to be a SU compared to SVA grade 0. Procedural and resource utilization factors were strong predictors of being a SU compared to patient factors. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Proximal junctional kyphosis (PJK) is a radiographic complication following adult spinal deformity (ASD) surgery. The decision-making process for PJK revision surgery is multi-faceted, involving the evaluation of clinical symptoms, radiographic findings, and patient-specific factors. To compare characteristics between ASD patients who received PJK revision at various time points and who did not receive PJK revision at all. Prospective, multicenter cohort of ASD patients with PJK. A total of 113 ASD patients who underwent surgery for complex spinal correction and developed PJK postoperatively. Spinopelvic parameters associated with the timing for revision surgery in patients who develop PJK following ASD surgery. Data was obtained from a multicenter database. Patients with ASD diagnosed with PJK were identified; those who had a revision within 6W were excluded due to the lack of postoperative films before 6W. The remaining patients were separated into groups: received revision surgery within two years, between two and four years, or no revision surgery within four years. Demographic variables were included. The SRS-22 questionnaire was used to assess health-related quality-of-life (HRQOL) at baseline. Spinopelvic parameters at 6W were collected, including C2-pelvic angle (C2PA), T4-pelvic angle (T4PA), L1-pelvic angle (L1PA), and T4PA-L1PA mismatch. Additionally, the incidence of preceding neurologic complications (within one year of PJK diagnosis) was determined. Hart-PJK severity score (PJKSS) was calculated without instrumentation or fracture components due to a lack of specific data. Bivariate analysis was performed with the Kruskal-Wallis and chi-squared tests. A total of 113 patients diagnosed with PJK were included. Six patients who had revision before six weeks postoperatively were excluded. Forty-seven patients (41.6%) had a revision surgery between 6 weeks and 2 years, 18 had a revision between 2 and 4 years (15.9%), and 48 patients (42.5%) had no revision surgery within 4 years. There were no significant differences between C2PA (p = 0.719), T4PA (p = 0.701), L1PA (p = 0.934), and T4PA-L1PA mismatch (p = 0.613) at 6W between the three groups. Likewise, the incidence of neurologic complications was not significantly different (p = 0.797). Early 6W postoperative spinopelvic parameters and the incidence of neurologic complications do not explain the timing of revision surgery. Additionally, demographics and HRQOL are similar among patients who received revision surgery for PJK and those who did not. Surgeons may be utilizing different variables for early risk stratification of PJK revision. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Background: For cervical deformity (CD) surgery, goals include realignment, improved patient quality of life, and improved clinical outcomes. There is limited research identifying patients most likely to achieve all three. Objective: The objective is to create a model predicting good 1-year postoperative realignment, quality of life, and clinical outcomes following CD surgery using baseline demographic, clinical, and radiographic factors. Methods: Retrospective review of a multicenter CD database. CD patients were defined as having one of the following radiographic criteria: Cervical sagittal vertical axis (cSVA) >4 cm, cervical kyphosis/scoliosis >10°° or chin-brow vertical angle >25°. The outcome assessed was whether a patient achieved both a good radiographic and clinical outcome. The primary analysis was stepwise regression models which generated a dataset-specific prediction model for achieving a good radiographic and clinical outcome. Model internal validation was achieved by bootstrapping and calculating the area under the curve (AUC) of the final model with 95% confidence intervals. Results: Seventy-three CD patients were included (61.8 years, 58.9% F). The final model predicting the achievement of a good overall outcome (radiographic and clinical) yielded an AUC of 73.5% and included the following baseline demographic, clinical, and radiographic factors: mild-moderate myelopathy (Modified Japanese Orthopedic Association >12), no pedicle subtraction osteotomy, no prior cervical spine surgery, posterior lowest instrumented vertebra (LIV) at T1 or above, thoracic kyphosis >33°°, T1 slope <16 and cSVA <20 mm. Conclusions: Achievement of a positive outcome in radiographic and clinical outcomes following surgical correction of CD can be predicted with high accuracy using a combination of demographic, clinical, radiographic, and surgical factors, with the top factors being baseline cSVA <20 mm, no prior cervical surgery, and posterior LIV at T1 or above. [ABSTRACT FROM AUTHOR]

Study Design: Multicenter database review of consecutive adult spinal deformity (ASD) patients.Objective: The aim of this study was to identify associations between changes in spinopelvic parameters and cervical alignment after thoracolumbar arthrodesis for ASD.Summary Of Background Data: Reciprocal cervical changes occur after instrumented thoracic spinal arthrodesis. The timing and relationship of these changes to sagittal alignment and upper instrumented vertebra (UIV) selection are unknown.Methods: In 171 ASD patients treated with thoracolumbar arthrodesis from 2008 to 2012, we assessed changes from baseline to 6-week, 1-year, and 2-year follow-up in C2-C7 sagittal vertical axis (SVA), T1 slope, and C2-C7 lordosis. We used multivariate models to analyze associations between these parameters and UIV selection (T9 or distal vs. proximal to T9) and changes at each time point in thoracic kyphosis (TK), lumbar lordosis (LL), C7-S1 SVA, pelvic incidence, pelvic tilt, and sacral slope.Results: Two-year changes in C2-C7 SVA and T1 slope were significantly associated with baseline to 6-week changes in TK and LL and with UIV selection. Baseline to 2-year changes in C2-C7 lordosis were associated with baseline to 6-week changes in C7-S1 SVA (P = 0.004). Most changes in C2-C7 SVA occurred during the first 6 weeks postoperatively (mean 6-week change in C2-C7 SVA: 2.7 cm, 95% confidence interval [CI]: 0.7-4.7 cm; mean 2-year change in SVA: 2.3 cm, 95% CI: -0.1 to 4.6 cm). At 2 years, on average, there was decrease in C2-C7 lordosis, most of which occurred during the first 6 weeks postoperatively (mean 6-week change: -3.2°, 95% CI: -4.8° to -1.2°; mean 2-year change: -1.3°, 95% CI: - 3.2° to 0.5°).Conclusion: After thoracolumbar arthrodesis, reciprocal changes in cervical alignment are associated with postoperative changes in TK, LL, and C7-S1 SVA and with UIV selection. The largest changes occur during the first 6 weeks and persist during 2-year follow-up.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Background Context: The postoperative recovery patterns of cervical deformity patients, thoracolumbar deformity patients, and patients with combined cervical and thoracolumbar deformities, all relative to one another, is not well understood. Clear objective benchmarks are needed to quantitatively define a "good" versus a "bad" postoperative recovery across multiple follow-up visits, varying deformity types, and guide expectations.Purpose: To objectively define and compare the complete 2-year postoperative recovery process among operative cervical only, thoracolumbar only, and combined deformity patients using area-under-the-curve (AUC) methodology.Study Design/setting: Retrospective review of 2 prospective, multicenter adult cervical and spinal deformity databases.Patient Sample: One hundred seventy spinal deformity patients.Outcome Measures: Common health-related quality of life (HRQOL) assessments across both databases included the EuroQol 5-Dimension Questionnaire and Numeric Rating Scale (NRS) back pain assessment. In order to compare disability improvements, the Neck Disability Index (NDI) and the Oswestry Disability Index (ODI) were merged into one outcome variable, the ODI-NDI. Both assessments are gauged on the same scale, with minimal question deviation. Sagittal Radiographic Alignment was also assessed at pre- and all postoperative time points.Methods: Operative deformity patients >18 years old with baseline (BL) to 2-year HRQOLs were included. Patients were stratified by cervical only (C), thoracolumbar only (T), and combined deformities (CT). HRQOL and radiographic outcomes were compared within and between deformity groups. AUC normalization generated normalized HRQOL scores at BL and all follow-up intervals (6 weeks, 3 months, 1 year, and 2 year). Normalized scores were plotted against follow-up time interval. AUC was calculated for each follow-up interval, and total area was divided by cumulative follow-up length, determining overall, time-adjusted HRQOL recovery (Integrated Health State, IHS). Multiple linear regression models determined significant predictors of HRQOL discrepancies among deformity groups.Results: One hundred seventy patients were included (27 C, 27 T, and 116 CT). Age, BMI, sex, smoking status, osteoporosis, depression, and BL HRQOL scores were similar among groups (p >. 05). T and CT patients had higher comorbidity severities (CCI: C 0.696, T 1.815, CT 1.699, p = .020). Posterior surgical approaches were most common (62.9%) followed by combined (28.8%) and anterior (6.5%). Standard HRQOL analysis found no significant differences among groups until 1-year follow-up, where C patients exhibited comparatively greater NRS back pain (4.88 vs. 3.65 vs. 3.28, p = .028). NRS Back pain differences between groups subsided by 2-years (p>.05). Despite C patients exhibiting significantly faster ODI-NDI minimal clinically important difference (MCID) achievement (33.3% vs. 0% vs. 23.0%, p < .001), all deformity groups exhibited similar ODI-NDI MCID achievement by 2-years (51.9% vs. 59.3% vs. 62.9%, p = 0.563). After HRQOL normalization, similar results were observed relative to the standard analysis (1-year NRS Back: C 1.17 vs. T 0.50 vs. CT 0.51, p < .001; 2-year NRS Back: 1.20 vs. 0.51 vs. 0.69, p = .060). C patients exhibited a worse NRS back normalized IHS (C 1.18 vs. T 0.58 vs. CT 0.63, p = .004), indicating C patients were in a greater state of postoperative back pain for a longer amount of time. Linear regression models determined postoperative distal junctional kyphosis (adjusted beta: 0.207, p = .039) and osteoporosis (adjusted beta: 0.269, p = .007) as the strongest predictors of a poor NRS back IHS (model summary: R2 = 0.177, p = .039).Conclusions: Despite C patients exhibiting a quicker rate of MCID disability (ODI-NDI) improvement, they exhibited a poorer overall recovery of back pain with worse NRS back scores compared with BL status and other deformity groups. Postoperative distal junctional kyphosis and osteoporosis were identified as primary drivers of a poor postoperative NRS back IHS. Utilization of the IHS, a single number adjusting for all postoperative HRQOL visits, in conjunction with predictive modelling may pose as an improved method of gauging the effect of surgical details and complications on a patient's entire recovery process. [ABSTRACT FROM AUTHOR]

Study Design: 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 upper instrumented vertebra (UIV) between T9 and L1 were included. Patients were divided into those with postoperative reciprocal thoracic kyphosis (reciprocal kyphosis [RK]: change in unfused thoracic kyphosis [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° versus 6.1° for MT (n = 102) and the mean PJK angle change was 17.6° versus 5.7° for MT (all P < 0.001). RK and MT were similar in age, body mass index (BMI), sex, 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 sagittal vertical axis (SVA), pelvic tilt (PT), and T1 pelvic angle (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 health-related quality of life (HRQOL) except reciprocal kyphosis (RK) had worse Scoliosis Research Society questionnaire (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 (>65 yr) 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).Conclusion: 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: 3. [ABSTRACT FROM AUTHOR]

Objective To investigate the influence of surgeon specialty on 30-day postoperative complication rates for single-level lumbar discectomies. Methods All patients who underwent single-level lumbar discectomy between 2005 and 2014 were reviewed from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. Propensity score matching and univariate binary regression was used to determine whether surgeon subspecialty had an influence on 30-day postoperative complications. Results Of the 28,863 patients who underwent single-level lumbar discectomies during 2005–2014, 12,659 patients met inclusion criteria. Orthopedic surgeons performed 3733 operations (29.4%), and neurosurgeons performed 8926 operations (70.6%). A propensity-score matched sample of 7464 total cases (3732 orthopedic surgeon, 3732 neurosurgeon) was analyzed for the effect of surgeon specialty on 30-day outcomes. After propensity matching, orthopedic surgeons and neurosurgeons were similar in all postoperative outcomes, except for a slightly higher frequency of blood transfusions (0.3%, n = 11) in orthopedic versus neurosurgery patients (0.1%, n = 3; P = 0.032), although this did not remain significant after Bonferroni adjustment. Mean operative time was slightly longer for neurosurgeons (83.7 minutes) versus orthopedic surgeons (72.5 minutes; P < 0.001). There were no significant differences in mortality, readmission, or reoperation rates. Conclusions Single-level lumbar discectomies hold a low complication profile and show equivalent outcomes for both orthopedic and neurological surgeons, although neurosurgeons may exhibit a slightly longer mean operative time. In propensity score–matched cohorts, orthopedic surgeons had slightly higher rates of blood transfusions, although the number was small and did not remain significant after Bonferroni adjustment. Highlights • Single-level lumbar discectomies hold a low overall complication profile. • Orthopedic and neurological surgeons have equivalent discectomy outcomes. • Orthopedic surgeons had slightly more blood transfusions versus neurosurgeons. • Neurosurgeons had a slightly longer mean operative time versus orthopedic surgeons. [ABSTRACT FROM AUTHOR]

While reimbursement is centered on 90-day outcomes, some patients persevere through these short-term, transient complications and manage to still achieve optimal, long-term outcomes. Assess whether achieving optimal alignment suffering similar perioperative complications compared to suboptimally-aligned peers are inhibited from reaching long-term clinical success and better cost-utility. Retrospective cohort study of a prospective adult spinal deformity (ASD) database. A total of 1,541 patients. Cost-per-QALY, radiographic realignment, clinical outcomes. Operative ASD pts with 2Y data were included. Optimal radiographic outcome was defined by SRS-Schwab low deformity in PI-LL, matched in T1PA and being aligned in PI-based PT at 6 weeks. After stratifying pts based on meeting optimal outcome, multivariate analysis controlling for baseline demographics was used to determine significance for complications and hospital-acquired conditions (HACs; DVT/PE, UTI, deep/superficial infection). Calculated Cost per QALY for each time point by 2Y. There were 917 ASD pts included. Regarding approach, 69% posterior approach, 31% combined. Groups: 131 were "optimal" (O) and 786 were "not optimal" (NO). Means comparison tests revealed significant differences in age, BMI, but not gender or frailty. The NO group had fewer osteotomies and a lower Invasiveness Index. Analysis of perioperative complications showed that the O group suffered equivocal perioperative complications (58.0% vs 52.2% in the NO group; p=.173) and rates of HACs (9.0% vs. 8.9%, p=.810). Analysis of long-term complications showed that patients in the NO group suffered more major neurological (p=.015) and major mechanical complications (p=.025), and more reoperations (28.7% vs 19.9%; p=.037). When controlling for baseline deformity, age, BMI and frailty, Optimal Outcome patients more often met Best Clinical Outcome (21.5% vs. 11.7%, p=.002). Cost-utility adjusted analysis with determined no difference in the two groups by 6 weeks and 6 months. However, the O group generated significantly better cost-utility by one year, which maintained lower Costs per QALY (p=.005) at two years in favor of the O group. Despite incurring equivocal perioperative complications, patients who met our optimal outcome criteria experienced significantly less mechanical complications and reoperations by 2 years, leading to a better long-term cost-utility overall. Accordingly, a higher, transient perioperative complication profile should not preclude surgical correction and future policy efforts should place more consideration on the long-term for outcome measures in adult spinal deformity surgery. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Surgical intervention has been shown to be an effective treatment modality for adult cervical deformity (CD), yet patient-reported outcomes vary even when patients are optimally realigned. While patients with higher baseline disability have more room for improvement, we propose there may be a threshold beyond which greater disability limits health-related quality of life (HRQL) improvement due to elevated risks and a point of no return. To assess impact of baseline disability on HRQL outcomes. Retrospective study of prospectively enrolled CD patients in a multicenter CD database. A total of 116 CD patients were included. HRQL, neck disability index (NDI), modified Japanese Orthopaedic Association (mJOA), EuroQol-5 Dimension (EQ5D). CD patients with baseline (BL) and 2-year follow-up (2Y) were included. The cohort was ranked into quartiles by baseline NDI, from lowest/best score (Q1) to highest/worst score (Q4). Means comparison tests analyzed differences between disability groups. Multivariate Analyses (MVA) assessed differences in outcomes of interest controlling for covariates including BL deformity, HRQLs, surgical details and complications. A total of 116 patients met inclusion criteria (age: 60.97±10.45 yrs, BMI: 28.73±7.59kg/m2, CCI: 0.94±1.31). The cohort presented with mean BL cSVA was 38.54 ± 19.43mm, TS-CL: 37.34 ± 19.73, and mJOA: 13.62 ± 2.71. Surgically, patients had an average of 8.44 ± 3.41 levels fused, with 53.5% of patients undergoing decompression and 48.3% undergoing osteotomy. Mean BL NDI and numerical rating scale (NRS) of the cohort were 48.33 ± 17.99 and 6.74 ± 2.48 respectively. Mean BL NDI by disability group was as follows: Q1: 25.04 ± 8.19, Q2: 41.61 ± 2.77, Q3: 53.31 ± 4.32, and Q4: 69.52 ± 8.35. MVA assessing improvement in NRS neck and NRS back, found significant differences between disability groups (both p=.007). Patients in Q2 demonstrated the greatest improvement in NRS neck at 2 years (-3.93), which was greater than those in Q3 (-1.61, p=.032) and Q4 (-1.41, p=.015). Patients in Q2 demonstrated greater improvement in NRS back at 2 years (-1.71), compared to those in Q4 (+0.84, p=.010). Rates of MCID in NRS neck were also significantly different across disability groups (p=.023). Patients in Q2 met MCID at the highest rates (69.9%) of all groups, higher than those in Q4 (30.3%), p=.039. MVA found patients in Q2 demonstrated the greatest improvement in EQ5D at 2 years (+0.082), compared to Q1 (+0.073), Q3 (+0.022), and Q4 (+0.014), p=.034. Finally, patients in Q2 demonstrated the greatest improvement in mJOA score from baseline (+1.517), p=.042. Patients in Q2, with mean baseline NDI of 42, consistently demonstrated the greatest improvement in HRQLs whereas those in Q4, with mean baseline NDI of 70, saw the least improvement. Thus, baseline NDI between 39 and 44 may represent a disability "wweet spot," within which operative intervention maximizes patient reported outcomes. Furthermore, delaying intervention until patients are severely disabled, beyond an NDI of 61, limits benefits of surgical correction in cervical deformity patients. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Prophylaxis usage has been established in literature as an important component of minimizing the risk of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) development. However, literature is scarce on the effects of prophylaxis in patients who have achieved adequate postoperative alignment and those who maintained poor alignment postoperatively. To investigate how PJK prophylaxis impacts rates of PJK and PJF with and without ideal alignment and the associated cost/cost-effectiveness. Retrospective cohort study of a prospective adult thoracolumbar deformity database. This study included 1,541 patients. Radiographic alignment, patient-reported outcome measures (ODI), cost per QALY. Operative adult spinal deformity patients (scoliosis >20°, SVA>5cm, PT>25°, or TK>60°) with an UIV at L1 or below and available baseline (BL) and 2-year (2Y) radiographic and HRQL data were included. "Matched" and "unmatched" alignment refers to the age-adjusted alignment criteria. PJK prophylaxis was defined by usage of cement, hooks or tethers. PJF was defined as PJK with reoperation. Costs were calculated using the PearlDiver database, accounting for additional costs of prophylaxis when applicable, through estimates from Medicare pay scales for services within a 30-day window, including estimates regarding costs of postoperative complications, outpatient healthcare encounters, revisions and medical related readmissions. QALY was calculated using SF6D. A total of 738 ASD patients or below met inclusion criteria (59.9yrs±14.0, 79%F, BMI: 27.7 kg/m2 ±6.0, CCI: 1.8 ±1.7). Surgically, patients had a mean level fused of 11.1±4.4, LOS of 7.9 days±4.4, EBL of 1577 mL, operative time of 377 min, with 63% undergoing an osteotomy. Forty percent of patients had PJK prophylaxis. Controlling for age, CCI, BL osteoporosis, levels fused, usage of 3CO, UIV, BL SVA and BL PI-LL, patients who were matched postoperatively in PT, SVA, or PI-LL had lowered PJF rates (OR:.5, 95% CI:.28-.86, p=.01) with prophylaxis. Among those unmatched in either SVA, PILL, or PT by 6W, prophylaxis significantly reduced the rates of PJK and PJF as well (p <0.05). ANCOVA controlling for age, CCI, BL osteoporosis, levels fused, usage of 3CO, UIV, BL SVA and BL PI-LL shows patients with ideal age-adjusted alignment and prophylaxis resulted in a lower cost per QALY by 2Y ($399,948 vs $514,228, p <.001). Similarly, in unmatched patients, prophylaxis resulted in a substantially lower cost per QALY by 2Y ($466,409 vs 672, 024, p <.001), primarily due to decreased costs of reoperation and greater improvements in QALY among prophylaxis cohorts. Despite additional surgical cost, optimization of radiographic realignment in conjunction with utilization of proximal junctional failure prophylactic techniques achieves ideal cost utility, predominately due to the minimization of mechanical failure related reoperations. Even among those not achieving optimal alignment, junctional prophylactic measures improved cost utility, emphasizing its critical role of minimization of junctional failures to achieve cost efficiency in adult spinal deformity surgery. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Background Context: Non-operative management is a common initial treatment for patients with adult spinal deformity (ASD) despite reported superiority of surgery with regard to outcomes. Ineffective medical care is a large source of resource drain on the health system. Characterization of patients with ASD likely to elect for operative treatment from non-operative management may allow for more efficient patient counseling and cost savings.Purpose: This study aimed to identify deformity and disability characteristics of patients with ASD who ultimately convert to operative treatment compared with those who remain non-operative and those who initially choose surgery.Study Design/setting: A retrospective review was carried out.Patient Sample: A total of 510 patients with ASD (189 non-operative, 321 operative) with minimum 2-year follow-up comprised the patient sample.Outcome Measures: Oswestry Disability Index (ODI), Short-Form 36 Health Assessment (SF-36), Scoliosis Research Society questionnaire (SRS-22r), and spinopelvic radiographic alignment were the outcome measures.Methods: Demographic, radiographic, and patient-reported outcome measures (PROMs) from a cohort of patients with ASD prospectively enrolled into a multicenter database were evaluated. Patients were divided into three treatment cohorts: Non-operative (NON=initial non-operative treatment and remained non-operative), Operative (OP=initial operative treatment), and Crossover (CROSS=initial non-operative treatment with subsequent conversion to operative treatment). NON and OP groups were propensity score-matched (PSM) to CROSS for baseline demographics (age, body mass index, Charlson Comorbidity Index). Time to crossover was divided into early (<1 year) and late (>1 year). Outcome measures were compared across and within treatment groups at four time points (baseline, 6 weeks, 1 year, and 2 years).Results: Following PSM, 118 patients were included (NON=39, OP=38, CROSS=41). Crossover rate was 21.7% (41/189). Mean time to crossover was 394 days. All groups had similar baseline sagittal alignment, but CROSS had larger pelvic incidence and lumbar lordosis (PI-LL) mismatch than NON (11.9° vs. 3.1°, p=.032). CROSS and OP had similar baseline PROM scores; however, CROSS had worse baseline ODI, PCS, SRS-22r (p<.05). At time of crossover, CROSS had worse ODI (35.7 vs. 27.8) and SRS Satisfaction (2.6 vs. 3.3) compared with NON (p<.05). Alignment remained similar for CROSS from baseline to conversion; however, PROMs (ODI, PCS, SRS Activity/Pain/Total) worsened (p<.05). Early and late crossover evaluation demonstrated CROSS-early (n=25) had worsening ODI, SRS Activity/Pain at time of crossover (p<.05). From time of crossover to 2-year follow-up, CROSS-early had less SRS Appearance/Mental improvement compared with OP. Both CROSS-early/late had worse baseline, but greater improvements, in ODI, PCS, SRS Pain/Total compared with NON (p<.05). Baseline alignment and disability parameters increased crossover odds-Non with Schwab T/L/D curves and ODI≥40 (odds ratio [OR]: 3.05, p=.031), and Non with high PI-LL modifier grades ("+"/'++') and ODI≥40 (OR: 5.57, p=.007) were at increased crossover risk.Conclusions: High baseline and increasing disability over time drives conversion from non-operative to operative ASD care. CROSS patients had similar spinal deformity but worse PROMs than NON. CROSS achieved similar 2-year outcome scores as OP. Profiling at first visit for patients at risk of crossover may optimize physician counseling and cost savings. [ABSTRACT FROM AUTHOR]

Background Context: Complication rates for adult cervical deformity are poorly characterized given the complexity and heterogeneity of cases.Purpose: To compare perioperative complication rates following adult cervical deformity corrective surgery between a prospective multicenter database for patients with cervical deformity (PCD) and the Nationwide Inpatient Sample (NIS).Study Design/setting: Retrospective review of prospective databases.Patient Sample: A total of 11,501 adult patients with cervical deformity (11,379 patients from the NIS and 122 patients from the PCD database).Outcome Measures: Perioperative medical and surgical complications.Methods: The NIS was queried (2001-2013) for cervical deformity discharges for patients ≥18 years undergoing cervical fusions using International Classification of Disease, Ninth Revision (ICD-9) coding. Patients ≥18 years from the PCD database (2013-2015) were selected. Equivalent complications were identified and rates were compared. Bonferroni correction (p<.004) was used for Pearson chi-square. Binary logistic regression was used to evaluate differences in complication rates between databases.Results: A total of 11,379 patients from the NIS database and 122 patiens from the PCD database were identified. Patients from the PCD database were older (62.49 vs. 55.15, p<.001) but displayed similar gender distribution. Intraoperative complication rate was higher in the PCD (39.3%) group than in the NIS (9.2%, p<.001) database. The PCD database had an increased risk of reporting overall complications than the NIS (odds ratio: 2.81, confidence interval: 1.81-4.38). Only device-related complications were greater in the NIS (7.1% vs. 1.1%, p=.007). Patients from the PCD database displayed higher rates of the following complications: peripheral vascular (0.8% vs. 0.1%, p=.001), gastrointestinal (GI) (2.5% vs. 0.2%, p<.001), infection (8.2% vs. 0.5%, p<.001), dural tear (4.1% vs. 0.6%, p<.001), and dysphagia (9.8% vs. 1.9%, p<.001). Genitourinary, wound, and deep veinthrombosis (DVT) complications were similar between databases (p>.004). Based on surgicalapproach, the PCD reported higher GI and neurologic complication rates for combined anterior-posterior procedures (p<.001). For posterior-only procedures, the NIS had more device-related complications (12.4% vs. 0.1%, p=.003), whereas PCD had more infections (9.3% vs. 0.7%, p<.001).Conclusions: Analysis of the surgeon-maintained cervical database revealed higher overall and individual complication rates and higher data granularity. The nationwide database may underestimate complications of patients with adult cervical deformity (ACD) particularly in regard to perioperative surgical details owing to coding and deformity generalizations. The surgeon-maintained database captures the surgical details, but may underestimate some medical complications. [ABSTRACT FROM AUTHOR]

Background For patients with adult spinal deformity (ASD), surgical treatment may improve their health-related quality of life. This study investigates when the greatest improvement in outcomes occurs and whether incremental improvements in patient-reported outcomes during the first postoperative year predict outcomes at 3 years. Methods Using a multicenter registry, we identified 84 adults with ASD treated surgically from 2008 to 2012 with complete 3-year follow-up. Pairwise t tests and multivariate regression were used for analysis. Significance was set at P < 0.01. Results Mean Oswestry Disability Index (ODI) and Scoliosis Research Society-22r total (SRS-22r) scores improved by 13 and 0.8 points, respectively, from preoperatively to 3 years (both P < 0.001). From preoperatively to 6 weeks postoperatively, ODI scores worsened by 5 points ( P = 0.049) and SRS-22r scores improved by 0.3 points ( P < 0.001). Between 6 weeks and 1 year, ODI and SRS-22r scores improved by 19 and 0.5 points, respectively (both P < 0.001). Incremental improvements during the first postoperative year predicted 3-year outcomes in ODI and SRS-22r scores (adjusted R 2 = 0.52 and 0.42, respectively). There were no significant differences in the measured or predicted 3-year ODI ( P = 0.991) or SRS-22r scores ( P = 0.986). Conclusions In surgically treated patients with ASD, the greatest improvements in outcomes occurred between 6 weeks and 1 year postoperatively. A model with incremental improvements from baseline to 6 weeks and from 6 weeks to 1 year can be used to predict ODI and SRS-22r scores at 3 years. [ABSTRACT FROM AUTHOR]

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 Eighteen CSD cases were assembled, including a clinical vignette, cervical imaging (radiography, computed tomography/magnetic resonance imaging), and full-length standing radiography. Fourteen deformity surgeons (10 orthopedic, 4 neurosurgery) were queried regarding recommended surgical plans. Results There was marked variation in treatment plans across all deformity types. Even for the least complex deformities (moderate midcervical 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 or vertebral column resection, 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 the number of anterior (2–5) and posterior (6–19) fusion levels, and recommended osteotomies (41% pedicle subtraction osteotomy/vertebral column resection). 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. [ABSTRACT FROM AUTHOR]

Study Design. Retrospective review of prospective multicenter database. Objective. Quantify the incidence of new onset cervical deformity (CD) after adult spinal deformity surgery of the thoracolumbar spine, identify predictors of development, and determine the impact on outcomes. Summary of Background Data. High prevalence of residual CD has been identified after surgical treatment of adult spinal deformity. Development of new onset CD is less understood and its clinical impact unclear. Methods. A total of 215 patients with complete 2-year followup and full-length radiographs met inclusion criteria. CD was defined by T1 slope minus Cervical Lordosis (CL) more than 20 °, C2-C7 sagittal vertical axis more than 40 mm, or C2-C7 kyphosis more than 10 °. Univariate analysis was performed using t tests or tests of proportion. Multivariate logistic regression was used to determine independent predictors of new onset CD. The impact of CD on health-related quality of life and satisfaction was measured using repeated measures mixed models or logistic regression as appropriate, accounting for potential confounders. Results. The overall rate of CD at 2 years after surgery was 63%. Univariate analysis revealed that patients who developed new onset CD postoperatively had higher incidence of diabetes (7.35% vs. 1.28%, P = 0.05), increased preoperative C2-C7 sagittal vertical axis ( P = 0.04) and C2 slope ( P = 0.038), and smaller diameter rods used at surgery ( P = 0.032). Independent predictors of new onset CD at 2 years included: diabetes (odds ratio, 10.49; P = 0.046) and increased preoperative T1 slope minus cervical lordosis (odds ratio, 1.08/°; P = 0.022). Ending instrumentation below T4 was a negative predictor (odds ratio, 0.31; P = 0.019). Patients with and without CD experienced improvements in 2-year 36-Item Short Form Health Survey ( P = 0.0001), Oswestry Disability Index ( P = 0.0001), and Scoliosis Research Society ( P = 0.0001). Rates and overall improvement were similar. CD was not associated with decreased satisfaction ( P = 0.28). Conclusion. A total of 47.7% of patients without preoperative CD developed new onset postoperative CD after thoracolumbar surgery. Independent predictors of new onset CD at 2 years included diabetes, higher preoperative T1 slope minus cervical lordosis, and ending instrumentation above T4. Significant improvements in healthrelated quality of life scores occurred despite the development of postoperative CD. [ABSTRACT FROM AUTHOR]

With an aging population and increased prevalence of cervical deformity, corrective surgery is increasingly utilized as a treatment option. The goal of this study is to examine whether surgical advancements and expansion of knowledge over the years have improved or changed outcomes and the way we approach cervical deformity surgery. To investigate if outcomes or surgical approach have changed over time. Retrospective cohort study of a prospective adult cervical deformity (ACD) database. This study included 119 ACD patients. Complications after ACD surgery within 2 years, HRQL (NDI, mJOA, EQ5D) ACD patients (≥18 years) with complete baseline and 2-year HRQL and radiographic data were included. Descriptive analysis included demographics, radiographic, and surgical details. Patients were grouped into Group I (2013-2014) and Group II (2015-2017) by DOS. Univariate, and multivariate analysis determined differences in surgical, radiographic, and clinical outcomes between groups. A total of 119 cervical deformity patients met inclusion criteria (61.3years, 67%F, BMI: 29kg/m2, CCI: 0.96±1.3). Radiographically at baseline, patients presented with: PT: 18.8± 11.3; PI: 53.0±11.1; PI-LL: -.45±17.7; SVA:-4.34±66.8, TS-CL: 38.1 ±21.4; cSVA: 45.2±25.6. Surgically, 51.3% had osteotomies, 47.1% had a posterior approach, 34.5% combined approach, 18.5% anterior approach, with 7.6± 3.8 levels fused and EBL of 824 mL. Group I consisted of 72 patients, and Group II consisted of 47. Group II had a higher CCI (1.3 vs.72), more cerebrovascular disease (6% vs 0%, both p<0.05), and no difference in age, frailty, deformity, or cervical rigidity. Group II had a lower surgical invasiveness (9 vs 11, p<0.05), trended towards a lower EBL (677 vs 921, p=.124) and shorter LOS (5.1 vs 7.9, p=.065), with no difference in levels fused, approach, reoperations, DJK development, or HRQLs (p>0.05). Controlling for baseline deformity and age, patients in Group II underwent fewer three-column osteotomies.17[.04-.8], (p<0.05). Patients undergoing three-column osteotomies had a deformity primarily in the CT region (48%), followed by C (23%) and T (19%) with a similar distribution between Groups (p>0.05). Additionally, controlling for levels fused and three-column osteotomies, Group II experienced fewer minor complications.3[.09-.96], (p<0.05). At 2 years, Group II had fewer patients with a moderate/high Ames horizontal modifier (71.7% vs 88.2%), fewer patients who were overcorrected in PT (4.3% vs 18.1%) and fewer patients with a +, or ++ deformity in PT SRS-Schwab (9.1% vs 39.5%). In a site-specific subanalysis, controlling for age, CCI, baseline deformity, and levels fused, Group II experienced fewer adverse events than Group I.138[.027-.713], (p=.018). Despite operating on a higher risk cohort with more comorbidity, outcomes have remained consistent, indicating improvements in care. Surgically, there has been a reduction in the number of three-column osteotomies performed, suboptimal realignments, and fewer complications and adverse events. This suggests a better understanding of minimizing the risk of cervical deformity surgery with fewer invasive techniques. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Prior reports have focused on grading fusion status after adult spinal deformity (ASD) surgery; however, few focused on fusion status after 4-years postop. To identify risk factors for nonunion in a prospective cohort of ASD patients with long-term follow-up (=4 years). Prospective multicenter observational series. Database enrollment required age =18 years, scoliosis =20°, sagittal vertical axis (SVA) =5cm, pelvic tilt =25°, or thoracic kyphosis =60°. Fusions were rated as bilaterally fused (A), unilaterally fused (B), partially fused (C), or not fused (D). Primary outcome was fusion (grade A or B) vs nonunion (grade C or D) at minimum 4-year follow-up. Secondary outcome measures included health-related quality of life (HRQL) (Oswestry Disability Index [ODI], Short Form-36 [SF-36] scores, Scoliosis Research Society-22 [SRS-22r] scores). Surgically treated ASD patients prospectively enrolled into a multicenter study (2008-2020) were assessed for fusion (grade A or B) vs nonunion (grade C or D). Inclusion required postop fusion grading at minimum 4-year follow-up. Demographics, frailty, comorbidities, alignment (baseline and initial correction), index surgery (total levels fused, iliac fixation, interbody fusion [IBF], use of bone morphogenetic protein [BMP] and/or demineralized bone matrix [DBM], 3-column osteotomy [3CO]) were assessed to identify potential predictors of nonunion (grade C or D), which were then analyzed using Kaplan-Meier survival curves and log-rank comparisons. A total of 227 patients achieved minimum 4-year follow-up and were included (age 58±14y, 82% women, BMI 27±5kg/m2, 40% prior spine surgery, ASD-FI 0.31 [frail], 15% osteoporosis). Index operations had 12±4 posterior levels, 70% iliac fixation, 62% IBF, 76% had BMP, 33% had DBM (of which 52% also had BMP), and 15% had 3CO. At final follow-up, 61 patients (27%) demonstrated nonunion (grade C or D). Older age (61±14 vs 57±14, p=0.015), no BMP usage (p 60 years) had significantly higher probability of nonunion (log-rank test p=0.024), and BMP had protective effect (log-rank test p 0.05). This study demonstrated that older age (>60 years) was associated with significantly higher rates of nonunion at long-term follow-up (4 years) after ASD surgery, and that use of BMP had significant protective effect against this complication. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Abstract: In vitro spine flexibility testing has been performed using a variety of laboratory-specific loading apparatuses and conditions, making test results across laboratories difficult to compare. The application of pure moments has been well established for spine flexibility testing, but to our knowledge there have been no attempts to quantify differences in range of motion (ROM) resulting from laboratory-specific loading apparatuses. Seven fresh-frozen lumbar cadaveric motion segments were tested intact at four independent laboratories. Unconstrained pure moments of 7.5Nm were applied in each anatomic plane without an axial preload. At laboratories A and B, pure moments were applied using hydraulically actuated spinal loading fixtures with either a passive (A) or controlled (B) XY table. At laboratories C and D, pure moments were applied using a sliding (C) or fixed ring (D) cable–pulley system with a servohydraulic test frame. Three sinusoidal load-unload cycles were applied at laboratories A and B while a single quasistatic cycle was applied in 1.5Nm increments at laboratories C and D. Non-contact motion measurement systems were used to quantify ROM. In all test directions, the ROM variability among donors was greater than single-donor ROM variability among laboratories. The maximum difference in average ROM between any two laboratories was 1.5° in flexion-extension, 1.3° in lateral bending and 1.1° in axial torsion. This was the first study to quantify ROM in a single group of spinal motion segments at four independent laboratories with varying pure moment systems. These data support our hypothesis that given a well-described test method, independent laboratories can produce similar biomechanical outcomes. [Copyright &y& Elsevier]

As operative measures and field knowledge advance, we hope that there is an improvement in outcomes for adult cervical deformity surgery. This improvement can be described by cost effectiveness, which encompasses operative cost, poor outcomes such as complications, and patient-reported measures. To determine whether surgical methods have improved by reducing the instance of complications and cost of cervical deformity (CD) surgery while improving patient reported outcomes. Retrospective cohort study of a prospectively enrolled multicenter CD database. A total of 132 CD patients. Complications, Reoperations, EQ5D, total cost, utility gained, Quality Adjusted Life Years (QALYs), Distal Junctional Kyphosis (DJK) CD patients with baseline (BL) and up to 2-year (2Y) HRQL data from 2013-2017 were included. Data from 2017 was combined with 2016 due to an incomplete year. ANCOVA found estimated marginal means of complications and reoperations adjusting for BL age, sex, surgical approach, and invasiveness. Cost was calculated using PearlDiver and assessed for Complications/Major Complications and Comorbidities according to CMS.gov. QALYs were calculated from EQ5D improvement and utilized 3% discount rate for residual decline to life expectancy (LE, 78.7 years). This data represents national average Medicare costs by surgical approach, complications and revision status. Trendline analysis noted changes over time. In a sub-analysis relating to a previous study, patients were identified by amount of risk factors for revision (UIV>C3, LIV>T3, C2-T3 SVA<46.7°, C2-C7 SVA>57.6°, CTPA>7.8°, and C2S<60.4) met. QALYs were calculated from NDI improvement in this analysis. There were 132 patients included in the study. Of these, 24 had surgery in 2013, 52 in 2014, 24 in 2015, and 32 in 2016. There was a trend downward with respect to 2-year total cost over the years (2013: $42,754; 2016: $39,155), as the trendline showed a yearly decrease of $2,753 (R2=0.6966). Concurrently, there was an increase EQ5D improvement after 2-year (2013: 0.0113; 2016: 0.0697). This resulted in an increase of 0.0172 per year in QALYs gained at 2-year (R2=0.8109) and a 0.2358 increase per year in QALYs gained at LE (R2=0.8533). Thus, there was a decrease in cost per QALY at 2-year of $6,057 per year (R2=0.0497) and at LE of $67,478 per year (R2=06588). Total cost at 2-year for those with Distal Junctional Kyphosis was $98,357 vs $59,129 for non-DJK; cost per QALY was $46,932 vs $28,571, respectively. Sub-analysis indicated increasing risk criteria were associated with major complications (2.085 [1.057-4.114], p=0.034) and reoperations (4.267 [1.604-11.352], p=0.004). Cost increased by $7,167 per factor (R2=0.9901). Patients with fewer factors had greater NDI improvement than high risk (1: -24.6; 2: -14.8; 3: -15.6; 4: -3.8, p=0.023). This translated to low cost per QALY at 2-year for 1 factor ($45,787), with worse cost efficiency per factor (2: $90,117; 3: $103,543; 4: $525,472). Between 2013 and 2017, total cost for cervical deformity surgery decreased – possibly due to complication and risk reductions – while EQ5D improvement has increased, leading to improved cost effectiveness. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Novel analyses of clinical outcomes following cervical deformity (CD) corrective surgery use an area-under-the-curve (AUC) method to assess health-related quality of life (HRQL) metrics throughout the surgical recovery process. It remains unclear how demographics, preop parameters, and surgical decisions are associated with superior recovery. Identify demographic, surgical and radiographic factors that predict superior recovery kinetics. Retrospective review of a prospective CD database. A total of 98 CD patients. Baseline (BL) to 1-year (1Y) HRQL Instruments: Neck Disability Index (NDI). CD database criteria:C2-7 Cobb angle>10°, coronal Cobb angle >10°, cSVA>4cm or TS-CL>10°, or CBVA>25°. Following univariate analyses, the AUC normalization method was utilized by dividing all reported BL and postoperative(3M, 1Y) outcome measures by the BL score. Normalized scores(y-axis) were plotted against follow-up time interval(x-axis). Total area was calculated for all follow-up, divided by cumulative follow-up length, determining overall, time-adjusted HRQL recovery (Integrated Health State[IHS]). IHS NDI scores were stratified by quartile, the uppermost 25% were categorized as having "superior" recovery kinetics (SRK) vs "normal" recovery kinetics (NRK). BL demographic, clinical and surgical information were used to predict SRK using generalized linear modeling. A total of 98 patients included(62±10yrs, 28±6kg/m2, 65%F). Mean CCI: 0.95, 6% smokers, and 31% history of smoking. Surgical approach: combined(33%), posterior(49%), anterior(18%). Average posterior levels fused: 8.7, anterior levels fused: 3.6, EBL: 915.9ccs, op time: 495min. According to the Ames CD classification at BL: cSVA (53.2% minor deformity and 46.8% moderate), TS-CL (9.8% minor, 4.3% moderate, 85.9% marked), and horizontal gaze (27.4% minor, 46.6% moderate, 26% marked). Relative to BL NDI scores (mean: 47), normalized postop NDI scores showed decrease in disability at 3M(0.9±0.5, p=0.260) and a further decrease at 1Y (0.78±0.41, p<0.001). As assessed with normalized NDI scores, patients showed significant improvement in neck disability from BL to 1Y postoperative (p<0.001). NDI IHS scores demonstrated correlation with age (p=0.011), gender (p=0.042), anterior approach only (p=0.042), posterior approach (p=0.042). After grouping by quartile, patients with greater BL PT (SRK:25.6°, NRK:17°, p=0.002), PI-LL (SRK:8.4°, NRK:-2.8°, p=0.009), and anterior approach (SRK:34.8%, NRK:13.3%; p=0.020) correlated strongly with SRK. A total of 69.4% of patients met MCID for NDI (<Δ-15) and 63.3% met SCB for NDI(<Δ-10), where 100% of SRK patients met both MCID and SCB. The final predictive model for SRK included(AUC=88.1%): BL VAS score for EQ5D (OR 0.96, CI:0.92-0.99), BL swallow sleep score(OR:1.04, CI:1.01-1.06), BL PT(OR:1.12, CI:1.03-1.22), BL mJOA score(OR:1.5, CI:1.07-2.16), BL T4-T12, BL T10-T12, BL T12-S1 and BL L1-S1. Superior recovery kinetics following cervical deformity surgery was predicted with high accuracy using a combination of baseline patient reported factors(VAS EQ5D, swallow sleep, and mJOA scores) and radiographic factors(TK, T10-T12, T12-S1, L1-S1). Patients and health care providers should be aware of these factors in order to improve surgical decision-making, in an effort to reduce postop neck disability. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Many patients are unable to undergo a major cervical deformity corrective surgery due to deformity severity, age, comorbidities, and overall frailty status. In order to optimize quality of life in patients with cervical deformity, there may be alignment targets to be prioritized. To prioritize the cervical parameter targets for alignment. Retrospective review of a multicenter prospective cervical deformity database. Seventy-seven patients undergoing cervical deformity (CD) corrective surgery. Cervical regional alignment parameters: cervical sagittal vertical axis(cSVA), cervical lordosis(CL), T1 Slope minus CL(TS-CL), chin brow vertical angle(CBVA), McGregor's slope(MGS), C2-T3 plumb line(C2-T3 SVA), C2-T3 angle, C2 Slope. Health-related quality of life measures: NDI. Included:CD patients (C2-C7 Cobb>10°, CL>10°, cSVA>4cm, or CBVA>25°) with full baseline (BL) and 1-year (1Y) radiographic parameters and NDI scores; patients with cervical or cervicothoracic Primary Driver Ames type. Patients with BL Ames classified as low CD for both parameters of cSVA(<4cm) and TS-CL(<15°) were excluded. Patients assessed: Meeting MCID for NDI(<-15 ΔNDI). Ratios of correction were found for regional parameters (cSVA, CL, T1 Slope, TS-CL, CBVA, MGS, C2-T3 SVA, C2-T3 angle, C2 Slope) categorized by Primary Ames Driver (cervical[C] or cervicothoracic[CT]). Decision tree analysis assessed cut-offs for differences associated with meeting NDI MCID at 1Y. Seventy-seven CD patients included (62.1yrs, 64%F, 28.8kg/m2). Average CCI: 0.94, 7% current smokers. By approach, anterior: 19.4%, posterior: 41.6%, combined approach: 39%. Mean anterior levels fused: 3.5, posterior: 8.3, total: 7.5. Average op time: 553.1min; mean EBL: 1128.1ccs. 41.6% met MCID for NDI. A backwards linear regression model including radiographic differences as predictors from BL to 1 year for meeting MCID for NDI demonstrated an R2 of 0.820 (p=0.032) included TS-CL, cSVA, MGS, C2SS, C2-T3 angle, C2-T3 SVA, CL. By primary Ames driver, 67.5% of patients were categorized as C, and 32.5% as CT. Ratios of change in predictors for MCID NDI patients (BL -1Y) for C driver patients: 260.8% MGS, 140.3% CL, 121.2% C2-T3 angle, 49.6% C2 slope, 41.1% cSVA, 20.5% TS-CL, 3.1%C2-T3 SVA. While correction in CT driver patients included: 168.7% CL, 93% MGS, 70.8% C2-T3 angle, 31.1% cSVA, 27.5% C2 slope, 24.9% TS-CL, 13.7% C2-T3 SVA. The ratios were not significant between the two groups(p>0.050). Decision tree analysis determined cut-offs for radiographic change, prioritizing in the following order (based upon ordinal regression values): a correction ≤42.5°C2-T3 angle (OR: 5.667[1.074-29.891], p=0.041), <35.4°CL (OR:4.636[0.857-25.071], p=0.075), >-31.76°C2 slope (OR: 3.2 [0.852-12.026], p=0.085), >-11.57mm cSVA (OR: 3.185[1.137-8.917], p=0.027), >-2.16° MGS (OR: 2.724[0.971-7.636], p=0.057). Certain ratios of correction of cervical parameters contribute to improving neck disability. Specific cut-offs of radiographic differences from baseline to 1 year were found prioritizing C2-T3 angle, followed by cervical lordosis, C2 slope, C2-C7 plumb line, and McGregor's slope, all strongly associated with meeting the minimal clinically important difference for the neck disability index score. Prioritizing these radiographic alignment parameters will optimize patient-reported outcomes for patients undergoing cervical deformity surgery. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Background Substantial clinical benefit (SCB) represents a threshold above which patients recognize substantial improvement and represents a rational target for defining clinical success. In adult spinal deformity (ASD) surgery, previous fusions may impact outcomes after deformity correction. Objective To investigate the impact of previous spinal fusion on the likelihood of reaching SCB thresholds for 2-year health-related quality of life (HRQOL) after ASD surgery. Methods We conducted a retrospective review comparing baseline demographic, HRQOL, and radiographic features for patients with ASD undergoing primary versus revision procedures. The primary outcome measure was reaching SCB threshold in Oswestry Disability Index (ODI), SF-36 Physical Component Summary (PCS), and back and leg pain (numeric rating scale). Secondary outcomes included absolute and change scores in ODI, PCS, and back and leg pain. Results In total, 332 patients achieved 2-year follow-up (228 primary; 104 revision cases). Those undergoing revision surgery had similar demographic features (age 58.3/55.9, female 80.8%/82.9%) to patients undergoing primary surgery. They had worse baseline HRQOL (ODI 48.5/41.2, PCS 29.5/33.4, back 7.5/7.0, and leg pain 4.9/4.3; P < 0.001) and radiographic deformity (sagittal vertical axis 111.4/45.1, lumbopelvic mismatch 26.7/11.0, pelvic tilt 29.5/21.0; P < 0.0001). Nevertheless, the number of patients who reached SCB for ODI (38.3/36.3%), PCS (48.5/53.4%), back (53.1/60.5%), and leg pain numeric rating scale (28.6/36.9%) did not significantly differ. Revision patients had worse 2-year HRQOL for all measures. Conclusions Patients undergoing revision surgery have worse baseline HRQOL and deformity. Although they do not achieve the same absolute level of 2-year HRQOL outcome, they have a similar likelihood of reaching SCB threshold for improvement in 2-year HRQOL. [ABSTRACT FROM AUTHOR]

Objective To determine the value of a novel adult cervical deformity frailty index (CD-FI) in preoperative risk stratification. Methods We reviewed a prospective, multicenter database of adults with cervical spine deformity. We selected 40 variables to construct the CD-FI using a validated method. Patients were categorized as not frail (NF) (<0.2), frail (0.2–0.4), or severely frail (SF) (>0.4) according to CD-FI score. We performed multivariate logistic regression to determine the relationships between CD-FI score and incidence of complications, length of hospital stay, and discharge disposition. Results Of 61 patients enrolled from 2009 to 2015 with at least 1 year of follow-up, the mean CD-FI score was 0.26 (range 0.25–0.59). Seventeen patients were categorized as NF, 34 as frail, and 10 as SF. The incidence of major complications increased with greater frailty, with a gamma correlation coefficient of 0.25 (asymptotic standard error, 0.22). The odds of having a major complication were greater for frail patients (odds ratio 4.4; 95% confidence interval 0.6–32) and SF patients (odds ratio 43; 95% confidence interval 2.7–684) compared with NF patients. Greater frailty was associated with a greater incidence of medical complications and had a gamma correlation coefficient of 0.30 (asymptotic standard error, 0.26). Surgical complications, discharge disposition, and length of hospital stay did not correlate significantly with frailty. Conclusions Greater frailty was associated with greater risk of major complications for patients undergoing cervical spine deformity surgery. The CD-FI may be used to improve the accuracy of preoperative risk stratification and allow for adequate patient counseling. [ABSTRACT FROM AUTHOR]