Faculty Bibliography

STUDY DESIGN/UNASSIGNED:Cadaveric study. OBJECTIVE/UNASSIGNED:To evaluate accuracy, radiation exposure, and surgical time of a new robotic-assisted navigation (RAN) platform compared with freehand techniques in conventional open and percutaneous procedures. METHODS/UNASSIGNED:Ten board-certified surgeons inserted 16 pedicle screws at T10-L5 (n = 40 per technique) in 10 human cadaveric torsos. Pedicle screws were inserted with (1) conventional MIS technique (L2-L5, patient left pedicles), (2) MIS RAN (L2-L5, patient right pedicles), (3) conventional open technique (T10-L1, patient left pedicles), and (4) open RAN (T10-L1, patient right pedicles). Output included (1) operative time, (2) number of fluoroscopic images, and (3) screw accuracy. RESULTS/UNASSIGNED:= .650). CONCLUSION/UNASSIGNED:RAN significantly improved accuracy and decreased radiation exposure in comparison to freehand techniques in both conventional open and percutaneous surgical procedures in cadavers. RAN significantly increased setup time compared with both conventional procedures.

The aim of this study was to investigate the cost utility of treating non-frail versus frail or severely frail adult spinal deformity (ASD) patients. 79 surgical ASD patients >18 years with available frailty and ODI data at baseline and 2-years post-surgery (2Y) were included. Utility data was calculated using the ODI converted to the SF-6D. QALYs utilized a 3% discount rate to account for decline to life expectancy (LE). Costs were calculated using the PearlDiver database. ICER was compared between non-operative (non-op.) and operative (op.) NF and F/SF patients at 2Y and LE. When compared to non-operative ASD, the ICER was $447,943.96 vs. $313,211.01 for NF and F/SF at 2Y, and $68,311.35 vs. $47,764.61 for NF and F/SF at LE. Frail and severely frail patients had lower cost per QALY compared to not frail patients at 2Y and life expectancy, and had lower ICER values when compared to a non-operative cohort of ASD patients. While these results support operative correction of frail and severely frail patients, it is important to note that these patients are often at worse baseline disability, which is closely related to frailty scores, and have more opportunity to improve postoperatively. Furthermore, there may be a threshold of frailty that is not operable due to the risk of severe complications that is not captured by this analysis. While future research should investigate economic outcomes at extended follow up times, these findings support the cost effectiveness of ASD surgery at all frailty states.

INTRODUCTION/BACKGROUND:Outcomes after anterior cervical diskectomy and fusion (ACDF) and cervical total disk arthroplasty (TDA) are satisfactory, but related morbidity and revision surgery rates are notable. This study sought to determine complication variations among ACDF, TDA, and combined ACDF-TDA as well as predictors of postoperative complications. METHODS:Patients undergoing 1- to 2-level ACDF and/or TDA with at least a 2-year follow-up from 2009 to 2011 were identified from the Statewide Planning and Research Cooperative System database. Patient demographics, hospital-related parameters, mortality, and postoperative outcomes were compared, and their predictors were identified using multivariate logistic regression. RESULTS:A total of 16,510 and 449 individuals underwent ACDF and cervical TDA, respectively, and 201 underwent ACDF-TDA. ACDF-TDA patients had the highest rates of cardiac complications and pulmonary embolism (PE) (P ≤ 0.006), whereas TDA patients had higher individual surgical and device/implant/internal fixation complications (P ≤ 0.025). ACDF-TDA patients experienced the lowest rate of revisions. Cervical TDA increased the odds of any surgical complications (OR = 2.5, P = 0.002), overall complications (OR = 1.57, P = 0.034), and revisions (OR = 2.29, P < 0.001). Deyo index predicted any medical/surgical complications (OR = 1.43 and 1.19, respectively). Female sex was associated with increased odds of readmission (OR 1.30, P < 0.001) but was protective against medical complications (OR = 0.81, P = 0.013). DISCUSSION/CONCLUSIONS:Combined ACDF-TDA procedures were not associated with increases in 2-year individual or overall complications, readmissions, or revisions. LEVEL OF EVIDENCE/METHODS:Level 3-Therapeutic study.

BACKGROUND CONTEXT: While neurological complications are known to occur following cervical fusions, few studies with sufficient power have quantified the difference in neurological outcomes as posterior cervical fusion (PCF) surgical invasiveness increases. PURPOSE: Compare longer vs shorter PCF complication rates. STUDY DESIGN/SETTING: Retrospective review of the New York State Statewide Planning and Research Cooperative System (SPARCS) database. PATIENT SAMPLE: All patients undergoing >=2 level PCF. OUTCOME MEASURES: Ninety-day neurological or medical complications status post short-cervical (SC), long-cervical (LC), or long cervicothoracic (LCT).
METHOD(S): From the NYS Statewide Planning and Research Cooperative System (SPARCS) database, retrospective review of all patients who underwent >=2 level PCF from 2009-13 with <= 90-day follow-up were identified and stratified by levels fused: 2-3 (SC), 4-8 (LC), and >= 9 (LCT). Data on demographics, hospital-related parameters, and 90-day neurological and other complications, readmissions, and revisions were collected. Regression analysis identified independent predictors of neurologic and overall complications.
RESULT(S): A total of 6,981 patients were included (SC, n=2,964, LC, n=3,899, LCT, n=118). LC patients were older than SC and LCT (60.8 vs 58.2 and 56.1), while LCT patients were more often female (59.3% vs LC 42.1% and SC 44%) and had higher total charges ($187,996 vs LC $99,020 and SC $82,239) and LOS (12.4 vs 6.1 and 6.9 days), all p<0.001. LC had the highest C5-C7 nerve palsy and overall neurological complication rates compared to SC and LCT patients (3.3 vs 1.8 and 1.7%, p=0.001; 3.8 vs 2.3 and 2.5%, p<0.001). Adverse events of the phrenic and recurrent laryngeal nerve were comparable. Implant infection (0.2 vs 0.3 vs 3.4%), and total complication rates (20.3 vs 23.7 vs 42.4%) increased with the number levels fused SC, LC, and LCT respectively, p<=0.017. 90-day readmissions and revisions were comparable. Only LC was a predictor of sustaining 90-day neurological complication (OR=1.7), while both LCT and LC predicted 90-day medical (OR=3.5, 1.3) and total complications (OR=2.7, 1.2), respectively, p<=0.008.
CONCLUSION(S): Compared to 2-3 levels, longer PCF had higher C5-C7 nerve palsy rates (3.3%) and 70% increased odds of sustaining >=1 neurological complication. Longer PCF was also associated with increased rates of medical and total complications. This data can improve the ability to counsel patients regarding the risks and expectations of potential adverse outcomes preceding cervical fusion via posterior or combined anterior-posterior approach. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: With a heightened focus on prescription narcotic use in the United States, concern among surgeons has increased regarding preoperative and postoperative usage. However, the literature is scarce on outcomes of preoperative and prolonged opioid usage in adult spinal deformity (ASD) patients. PURPOSE: Investigate effect of preoperative opioid usage on prolonged opioid use postoperatively and rates of reoperations. STUDY DESIGN/SETTING: Retrospective review of the PearlDiver Database 2008-2013. PATIENT SAMPLE: A total of 7,661 ASD patients. OUTCOME MEASURES: Reoperations, 90-day complications, comorbidity burden, prolonged opioid usage METHODS: ASD patients undergoing a fusion were isolated in the PearlDiver database between the years 2008-2013 using ICD-9 and CPT codes. Patients were stratified by prescription preoperative opioid use 3 months prior to surgery: (1) high frequency (>4 refills); (2) low frequency (1-3 refills); (3) opioid naive. Means comparison tests compared differences in demographics, complications, and reoperation rates. Logistic regression assessed the odds of complication and reoperations associated with preoperative frequency and prolonged opioid use (3 to 6 months postop), controlling for age, sex, and comorbidities.
RESULT(S): A total of 7,661 ASD patients were isolated; 2,342 patients were high frequency preop opioid users, 2,247 low frequency preop opioid users, and 3,072 opioid naive. At BL, high frequency preop opioid users had higher rates of obesity, diabetes mellitus, CHF, COPD, hypertension, smoking and alcohol use (all p<0.001). Compared to opioid naive patients, low frequency preop opioid users had higher rates of 90-day complications associated with hematoma and transfusion (p<0.05). High frequency preop opioid users relative to naive opioid users had significantly increased 90-day complication rates including pulmonary embolism, pneumonia, hematoma, and transfusions. High frequency opioid use was associated with increased odds of wound disruption (1.74[1.22-2.51]) and hospital readmission (1.42[1.22-1.64], both p<0.05). Additionally, high frequency opioid usage preop followed by prolonged opioid use postop was associated with increased odds of reoperations at 2Y relative to low frequency (1.67[1.34-2.10]) and opioid naive patients (1.83[1.40-2.42], both p<0.001).
CONCLUSION(S): Patients with high frequency preoperative opioid use are at increased risk of major complications within 90 days of surgery, prolonged use postoperatively, and increased risk of reoperations within two years. During preoperative risk assessment, providers should consider the effect of pre- and postoperative opioid usage on patient outcomes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Scoliosis is frequently associated with Chiari malformation (CM). More specifically, reports have been made about this association with CM-1 in the absence of syrinx status. There is paucity in literature in the surgical risks associated with concurrent CM types and scoliosis diagnosis. PURPOSE: To identify the risks adolescent patients have when diagnosed with CM and scoliosis. STUDY DESIGN/SETTING: Adolescents in pts in Kids' Inpatient Database (KID) during the years of 2003-2012. PATIENT SAMPLE: A total of 35,073 Chiarim pts. OUTCOME MEASURES: Complications.
METHOD(S): CM and scoliosis pts were isolated in KID from 2003-2012. The patients were stratified into three groups: those with concomitant CM and scoliosis (CmS), those with only CM (OCm), and those with only scoliosis (Scol). Demographics, incidence, comorbidity profiles, surgical strategy, and postoperative complications were assessed. Comorbidity profiles were stratified by body systems (neurological, musculoskeletal, pulmonary, cardiovascular, renal). Groups were compared using t-tests and chi-squared tests for continuous and discrete variables, respectively. Multivariate logistic regressions were used to assess association between surgical characteristics/diagnosis with complication rate.
RESULT(S): Included 90,707 spine pts, 63.3% Scol, 38.7%Ocm, and 2.0%Cms. Scol were older (13.6yrs vs CM: 5.9 vs Both:10.9) and had a higher invasiveness score (2.4 vs OCm: 0.5 vs Both:1.5), while CmS pts were more comorbid (0.9 vs OCm: 0.55 vs Scol: 0.89; all p<0.001). CmS pts had higher rates of surgical decompression (25.4%) and Scol pts had higher rates of fusions (35.3%) and osteotomies (1.2%; all p<0.001). However, CmS pts had the highest surgical rate (37.1% vs Scol: 36.6% vs OCm:10.6%) among the cohort (p<0.001). Controlling for age and invasiveness, Scol pts receiving a fusion (1.8[1.08-3.2] operation were associated with development of postoperative complications as well as OCm osteotomies (2.9[1.4-6.0]) and fusions (1.8[1.2-2.9]), and CmS fusion surgeries (1.8[1.0-3.2]; all p<0.05). Having a complication of acute respiratory distress (2.1[3.4-1.3]) and anemia (0.6[0.85-0.36]) were independently associated with CmS operation (all p<0.05).
CONCLUSION(S): Having concurrent scoliosis and Chiari malformation increases operative risk for when decompressive surgeries are performed. Being independently inflicted with scoliosis or Chiari leads to increased complication rate when paired with fusion surgeries. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Prior studies demonstrated that symptomatic adult spinal deformity (SASD) is a heterogeneous condition with varying degrees of negative health impact depending on the specific type and severity of deformity. Currently, there is some controversy regarding the subset of SASD with global coronal malalignment (GCM) and its associated health impact. Moreover, few reports have assessed the health impact of this global coronal parameter in comparison to other deformity types. A comparative study of deformity types with severe global malalignment (eg, severe GCM) may provide clinically relevant insights and identify potential differences in demographics and health impact. PURPOSE: To compare demographics and health impact of SASD patients with severe global malalignment (primary sagittal [SAG-only] vs primary coronal [COR-only] vs sagittal+coronal [MIX]). STUDY DESIGN/SETTING: Retrospective analysis of a prospective multicenter database. PATIENT SAMPLE: Enrollment required age >=18 yrs and one of the following: scoliosis >=20degree, sagittal vertical axis (SVA) >=5cm, pelvic tilt >=25degree, and/or thoracic kyphosis >=60degree. OUTCOME MEASURES: Short Form-36 (SF-36) PCS score.
METHOD(S): Consecutive SASD patients from a prospective multicenter database were evaluated for type and severity of global malalignment. Severe alignment thresholds included SVA >=10cm (SAG-only), GCM >=6cm (COR-only), or both SVA >=10cm and GCM >=6cm (MIX). SF-36 PCS scores were compared with U.S. normative values.
RESULT(S): Of 492 SASD patients that met threshold alignment criteria, 463 (94%) completed the SF-36 and were included (78% women, mean age 65 years, mean BMI 28.6 kg/m2, previous spine surgery in 65%). Deformity types were SAG-only (58%), COR-only (19%) and MIX (23%). COR-only had more women (94%, p<0.001), younger age (61 years, p=0.004), and lower BMI (26 kg/m2, p<0.001). Charlson Comorbity Index (CCI) scores and total number of comorbidities were comparable among the deformity types (p>0.05). All deformity types were 'frail' based on ASD-Frailty Index scores (SAG-only [3.9], COR-only [3.1], MIX [4.0]). Overall mean PCS was lower compared to similar age- and gender-matched U.S. normative values (29.0 vs 45.3, p<0.001). Mean PCS was significantly different between deformity types (p<0.001): SAG-only (28.5) vs COR-only (33.1) vs MIX (27.0). PCS offsets from normative population scores were significantly different between deformity types (p=0.001): SAG-only (-16.6) vs COR-only (-13.4) vs MIX (-18.2).
CONCLUSION(S): Demographic comparisons demonstrated significantly more women, younger age, and lower BMI in the COR-only deformity type. Severe global malalignment (SVA >=10cm and/or GCM >=6cm) had substantial debilitating impact on health, with MIX deformity type (i.e., severe global sagittal and coronal malalignment) experiencing the greatest health impact. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: The Miller et al. adult spinal deformity frailty index (ASD-FI) correlates with increased complication risk after surgery; however, its development is rooted in health related quality of life metrics (HRQLs) that may be subjective, and the 40 factors needed for its calculation limit the index's utility in a clinical setting. PURPOSE: Develop a simplified, modified frailty index for ASD patients STUDY DESIGN/SETTING: Retrospective cohort study PATIENT SAMPLE: A total of 531 ASD patients OUTCOME MEASURES: HRQLs, length of stay (LOS) METHODS: ASD patients (scoliosis>=20degree, SVA>=5cm, PT>=25degree, or TK >=60degree) with baseline (BL) and 2-year HRQL follow up. HRQL components were removed from the FI and top contributors to the ASD-FI score of the remaining were assessed via Pearson correlation, and included in forward multiple stepwise regressions. Factors with the largest R2 value were including in the modified, ASD-FI (clin-ASD-FI). Factors included in the clin-ASD-FI were regressed against mortality, extended length of hospital stay (>8 days), revisions, major complications and weights for the clin-ASD-FI were calculated via Beta/Sullivan. Total clin-ASD-FI score was created with a score from 0 to 1. Linear regression correlated the clin-ASD-FI with ASD-FI scores and published cut-offs for the ASD-FI were used to create the new frailty cutoffs: not frail (NF: < 0.11), frail (F: 0.11-0.21) and severely frail (SF: >0.21). Binary logistic regression assessed odds of complication or reop for frail patients. Logistic regressions were run to determine whether the clin-ASD-FI is superior to previously utilized measures predicting risk (age, ASA, previous FI, and CCI) for complications and reop.
RESULT(S): A total of 531 ASD patients (59.5yrs, 79.5%F). The final stepwise regression model R2 of 0.681: <18.5 or >20 BMI (weight: 0.0625 out of 1), cardiac disease (0.125), disability employment status (0.3125), diabetes mellitus (0.0625), hypertension (0.0625), osteoporosis (0.125), blood clot (0.1875), and bowel incontinence (0.0625). These factors calculated the score from 0 to 1, with a mean cohort score of 0.13+/-0.14. Breakdown by clin-ASD-FI score: 51.8% NF, 28.1% F, 20.2% SF. Increasing frailty severity was associated with longer LOS (NF: 7.0, F: 8.3, SF: 9.2 days; p<0.001). When assessing BL HRQL status between the new clin-ASD-FI groups, ODI, EQ5D, SRS, PCS, MCS, NRS-Back, and NRS-Neck were worse with increasing categorical frailty (all p<0.001). Frailty independently predicted occurrence of any complication (9.357[2.20-39.76], p=0.002) and reop (2.79[0.662-11.72], p=0.162). Specific complications predicted included infection, neurologic, operative, radiographic, and wound complications (OR: 1.69-5, all p<0.001). Chi-square and p-values for the historical risk predictors of complications are as follows: Age(complication: 1.01[1-1.03] p=0.052; reop: 0.999[0.984-1.01] p=0.866), ASA(complication: 1.102[1.20-2.18], p=0.002; reop: 1.31[0.927-1.84], p=0.177), previous frailty index(complication: 8.57[1.66-44.17], p=0.010; reop=2.629[0.498-16.06], p=0.241), CCI(complication: 1.24[1.10-1.40], p<0.001; reop: 1.06[0.943-1.20], p=0.320).
CONCLUSION(S): Utilizing an existing ASD frailty index, we proposed a modified version eliminating the patient-reported components. This index is a true assessment of physiologic status, and represents a superior risk factor to other risk assessment tools for baseline and revision spinal deformity surgery as a result of its immutability with surgery, lack of subjectivity, and ease of use. Future studies should explore external validation of the proposed frailty index. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Adult spinal deformity (ASD) correction involves complex, invasive procedures. However, it is unknown how metabolic syndrome affects the cost efficiency of ASD surgery. PURPOSE: Investigate the differences in ASD surgery cost for metabolic syndrome patients. STUDY DESIGN/SETTING: Retrospective review of a single center ASD database. PATIENT SAMPLE: A total of 557 ASD patients. OUTCOME MEASURES: Complications, revisions and costs.
METHOD(S): ASD patients (scoliosis >=20degree, SVA>=5cm, PT >=25degree, or TK >=60degree) >=18, undergoing >=4 level fusions were included. Descriptive analysis assessed mean baseline demographic, radiographic and surgical data were assessed. Patients diagnosed with: BMI >30, diabetes mellitus, and HTN were classified metabolic syndrome patients (MetS). Independent samples T-tests assessed baseline differences in SVA, PT, PI-LL, and levels fused between MetS and non-MetS patients. Total surgery costs for MetS and non-MetS ASD patients were compared. Costs were calculated using the PearlDiver database, which reflects both private insurance and Medicare reimbursement claims. Complications and comorbidities (CC) and major complications and comorbidities (MCC) were assessed according to CMS.gov manual definitions.
RESULT(S): A total of 557 patients met inclusion criteria. Baseline demographics and surgical details: age 60.8 +/- 13.2, 67.5% female, BMI 28.3 +/- 6.67, 6.2% anterior approach, 81.0% posterior approach, 12.8% combined approach, 10.4 +/- 3.9 levels fused, op time 423.5 +/- 166.4 minutes, EBL 2061.4 +/- 1631.5 cc, LOS 7.6 +/- 5.4 days. 11 MetS patients were included. There was no significant difference in BL SVA (54.2degree vs 70.3degree), PT (26.7degree vs 23.7degree), PI-LL (16.4degree vs 21.2degree), or levels fused between groups (10.5 vs 10.6) (all p>0.05). Twenty-seven percent of MetS patients experienced a CC or MCC, with 18% undergoing revisions within 90 days (vs 13.2% and 3.2% for non-MetS, p<0.05). The average costs of surgery for MetS patients was $68,004.06 vs $48,726.40 for non-MetS patients (p<0.05).
CONCLUSION(S): Metabolic syndrome is a growing concern among health care providers. In metabolic syndrome patients undergoing corrective adult spinal deformity surgery, the total costs of surgery was 28.4% higher for metabolic syndrome patients ($68,004.06 vs $48,726.40). Optimizing modifiable factors like diabetes or BMI in preoperative patients may have an impact on cost effectiveness. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Adult spinal deformity (ASD) surgery is complex and may lead to new-onset cervical malalignment and/or proximal junctional kyphosis (PJK). Roussouly et al describes variations in baseline thoracolumbar (TL) shape (Types 1-4), which have been shown to differentially influence surgical ASD outcomes. The effect of morphological shape on patterns of postoperative CD development remains underexplored. PURPOSE: Stratify patients by Roussouly type and assess patterns of conversion from baseline (BL) cervical alignment to postoperative cervical deformity (CD) in patients undergoing thoracolumbar ASD surgery. STUDY DESIGN/SETTING: Retrospective review of a prospective multicenter database of ASD patients. PATIENT SAMPLE: A total of 266 surgical ASD patients. OUTCOME MEASURES: Rate and timing of conversion to CD, rate of PJK, radiographic alignment parameters.
METHOD(S): Operative ASD patients with complete radiographic data at baseline, 6W, 1Y, 2Y, & 3Y intervals were included. Patients were grouped by baseline PI and apex of LL into component types of the Roussouly classification system utilizing pelvic incidence as published by Pizones et al. Patients with no BL CD were postoperatively stratified by Ames CD criteria (TS-CL>20 degree, cSVA>40mm), where CD was defined as fulfilling >1 criteria. Follow-up intervals were established post-ASD surgery, with 6W postop defined as "Early," 6W-1Y "Intermediate," 1-2Y "Late," and 2-3Y "Long." Univariate and Cox regression analyses identified CD conversion rate and PJK rate (<-10degree change in UIV and UIV+2) across Roussouly types 1-4.
RESULT(S): A total of 266 surgical ASD patients (59.7yrs, 77.4% F) with complete radiographic data were included. By Roussouly classification, 9% were Type 1, 15.8% Type 2, 46.6% Type 3, and 28.6% Type 4. 28.6% of ASD patients converted to postop CD (Early: 14.3%, Intermediate: 5.3%, Late: 4.1%, Long: 4.9%). There were no significant differences in CD conversion rate across Roussouly types (1: 33.3%; 2: 28.6%; 3: 26.6%; 4: 30.3%, P=0.895). Types 2 (41.7%), 3 (60.6%), and 4 (43.5%) had their peak rates of conversion in the Early (<6w) window compared to other follow-up intervals, whereas Type 1 patients had a peak rate (50%) between 6w-1Y. Type 2 patients had higher rates of later CD conversion (>1 year) than other types (50% vs 28.1%, P=0.135), while Type 1 patients trended higher rates of earlier CD conversion (<1 year) than other types (33.8% vs 12.5%, P=0.220); these patterns did not reach statistical significance. Across Roussouly Types, among patients who converted to CD, Type 4 had significantly higher rates of ++ SRS-Schwab PT and greater TPA at BL (both p<0.05). Type 4 patients had the highest rate of concurrent PJK with CD conversion (60.9%) compared to Type 1 (50%), Type 2 (50%), or Type 3 (54.5%) (P>0.05). There were no significant change in ODI, PCS, or SRS total among Roussouly Types in patients that converted to CD (p>0.05). Random forest analysis determined the top surgical (levels fused), radiographic (TS-CL), and demographic (frailty) factors associated with CD conversion.
CONCLUSION(S): Baseline thoracolumbar shape as described by the Roussouly classification has a differential effect on timing to CD conversion, though overall rates of CD conversion after TL-ASD correction were similar across Types 1-4. Type 1 patients with a lower apex of lumbar lordosis trended earlier conversion, while Type 2 patients with a higher apex of LL trended conversion beyond 1-year postop. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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