Faculty Bibliography

BACKGROUND CONTEXT: Malalignment following adult spinal deformity (ASD) surgery can negatively impact clinical outcomes and increase risk of mechanical complications. Despite improved definition of ideal alignment for ASD surgery and increasingly sophisticated preoperative alignment planning tools, it remains unclear whether the preoperative goals for alignment are actually achieved with surgery. PURPOSE: The objective of this study was to assess whether preoperative goals for sagittal alignment following ASD surgery are consistently achieved. STUDY DESIGN/SETTING: Multicenter, prospective cohort study. PATIENT SAMPLE: Operatively treatedASD patients. OUTCOME MEASURES: Sagittal vertical axis (SVA), pelvic incidence to lumbar lordosis mismatch (PI-LL), T4-T12 thoracic kyphosis (TK).
METHOD(S): From 2018-2021, ASD patients were enrolled into a prospective ASD study based on three criteria: deformity severity (PI-LL>25degree, TPA>30degree, SVA>15cm, TCobb>70degree or TLCobb>50degree), procedure complexity (>12 levels fused, 3CO or ACR), and/or patient age (>65 and >7 levels fused). The operating surgeon documented sagittal alignment goals prior to surgery, including SVA, PI-LL mismatch and TK. Alignment goals were compared with achieved alignment at 6 weeks postop and the overall mean and SD were calculated for the offset (achieved minus goal) for each measure. Goal alignment was considered attained if the offset was within +/-1 SD of the goal. Demographic, surgical and baseline radiographic measures demonstrating significant association with achieving alignment goal on univariate analysis were used for multivariate regression analysis.
RESULT(S): The 266 enrolled patients had a mean age of 61.0 yrs (SD=14.6 yrs) and 68% were women. Mean number of instrumented levels was 13.6 (SD=3.8) and 24% had a 3-column osteotomy (3CO). Mean (SD) offsets were: SVA=-8.5 mm (45.6 mm), PI-LL=-4.6degree (14.6degree), TK=7.2degree (14.7degree), reflecting a tendency to undercorrect SVA and PI-LL relative to goal and to increase TK relative to goal. Surgeons achieved goal alignment (within 1 SD) for SVA, PI-LL, and TK in 74.4%, 71.4%, and 68.8% of cases, respectively. On regression analysis: goal SVA was more likely to be achieved with lower baseline SVA (OR=0.993, 95%CI=0.988-0.997, p=0.001) and greater baseline TK (OR=1.016, 95%CI=1.002-1.031, p=0.029); goal PI-LL was more likely to be achieved with greater patient age (OR=1.021, 95%CI=1.002-1.039, p=0.026) and history of previous TL spine surgery (OR=2.028, 95% CI=1.136-3.621, p=0.017); and goal TK was more likely to be achieved with lower baseline SVA (OR=0.995, 95%CI=0.991-0.999; p=0.014). The proportions of patients with achieved alignment within 1 SD of goal were not significantly different for patients with a UIV above T7 vs those with a UIV at or below T7 for SVA (p=0.20), PI-LL (p=0.49) or TK (p=0.06). Notably, patient-specific rods were used in 21 patients and were not associated with greater achievement of goal alignment for any parameter (p>0.8), with similar tendencies to undercorrect SVA and PI-LL and increase TK (p>0.6).
CONCLUSION(S): Surgeons failed to achieve goal alignment of each sagittal parameter in ~25% of patients operated for ASD, with a tendency to undercorrect SVA and PI-LL and increase TK. Patients at greatest risk tended to be those with more severe baseline deformity. Further advancements are needed to enable more consistent translation of preoperative alignment planning to the operating room. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: A previous study by Pellise et al identified strong preoperative and surgical predictors of major complications. It is unknown which of these risk factors has the most significant impact on cost-effectiveness. PURPOSE: To assess the impact of previously established risk factors on the cost effectiveness of ASD surgery. STUDY DESIGN/SETTING: Retrospective. PATIENT SAMPLE: A total of 689 ASD patients. OUTCOME MEASURES: Quality adjusted life years (QALYs), utility gained, ODI, total cost.
METHOD(S): ASD patients with baseline (BL) and 2-year postoperative (2Y) data were included. Frailty score, sagittal deformity measures (SVA, PI-LL, T1 Sagittal Tilt), blood loss and surgical time were divided into tertiles, with the highest tertile being classified as high risk. Since some patients have multiple risk factors, they may be included in multiple groups. Descriptive analysis identified demographics, radiographic parameters and surgical factors. Published methods for cost was calculated using the PearlDiver database and CMS.gov definitions. Cost per QALY at 2Y was calculated for each risk factor.
RESULT(S): There were 422 patients included. Of the 381 patients with a risk factor, 77% were fused to the pelvis, 44% were highly frail, 56% had a high deformity, 34% had high EBL and 34% had high operative time. When analyzing BL scores, highly frail patients had the highest mean ODI and EQ-5D. After undergoing surgery, patients with a high EBL had the highest rate of SICU admissions, rate of any complications and rate of major complications. This translated to patients with high EBL having the lowest utility gained at 2Y. Interestingly, patients with high frailty had the highest rates of implant complications and pseudarthrosis resulting in the second highest major complication rates and total estimated cost. Despite this high estimated cost, however, patients with high frailty also achieved the highest utility gained at 2Y resulting in the best cost-utility at two years.
CONCLUSION(S): Despite having higher rates of implant failures, pseudarthrosis, and major complications, highly frail patients managed to generate the highest utility gained and best cost-effectiveness, while higher blood loss had higher rates of complications as well, but demonstrated the lowest utility gained and cost-utility. Therefore, spine surgeons should limit intraoperative risk factors, such as blood loss and operative time, which would minimize postoperative complications and improve overall cost-effectiveness during correction of adult spinal deformity. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Bone Morphogenetic Protein-2 (BMP-2) has not shown superior benefit in terms of overall cost-effectiveness after implementation during adult spinal deformity (ASD) surgery. However, it remains to be shown whether certain discrete populations do obtain cost-utility from use of BMP-2. PURPOSE: Generate a score to determine usage of BMP-2 and correlate with rates of pseudarthrosis. STUDY DESIGN/SETTING: Retrospective cohort study of a single-center ASD database. PATIENT SAMPLE: A total of 689 ASD patients. OUTCOME MEASURES: Cost utility, pseudarthrosis.
METHOD(S): ASD patients with BL and 2-year(2Y) data included. BMP-2 kit size and cost: small - 4.2 mg ($21,800), medium - 8.4 mg ($23,667), large - 12 mg ($25,617). Published methods converted ODI to SF-6D. QALYs utilized a 3% discount rate for residual decline. Cost was calculated using the PearlDiver database and assessed for Complications and Comorbidities and Major Complications and Comorbidities according to CMS.gov definitions. Binary logistic regression analyses determined significant predictors for development of pseudarthrosis. Established weights were generated for predictive variables via back-step logistic regression for a risk score to predict development of pseudarthrosis. Risk score was then validated via Receiver Operating Characteristic (ROC) curve method analysis. Categories via conditional inference tree (CIT) analysis-derived thresholds were tested for cost-utility of BMP-2 usage. Marginalized means for utility gained and Cost per QALY were calculated within each risk score category, controlling for age, history of prior fusion, and baseline deformity and disability.
RESULT(S): Included: 387 ASD patients. Of 387, 64% received BMP-2 (1% small, 4% medium, 59% large). There were 17 (4.4%) of patients that developed pseudarthrosis by two years, 9 (2.3%) of which underwent reoperation. BMP-2 use, regardless of kit size, did not significantly lower pseudarthrosis rates overall (OR: 0.4, [0.2-1.04]). A predictive risk score for development of pseudarthrosis was formed by the following preoperative variables: age, frailty, history of diabetes, osteoporosis, depression, ASA grade, and baseline L4-S1 and T1PA. Via ROC method, this predictive risk score generated an AUC of 0.87. Following CIT machine learning, thresholds for the BMP Risk Score were derived: >5 No Risk (NoR), 3-5 Low Risk (LowR), 2-3 Moderate Risk (ModR), and <2 High Risk (HighR). The rates of pseudarthrosis for each category were: NoR - 0%; LowR - 1.6%; ModR - 9.3%; HighR - 24.3%. When assessing BMP-2 use and its cost-utility within each group, patients receiving BMP-2 had similar QALYs to those that did not receive BMP-2 (0.163 vs 0.171, p=.65). BMP-2 usage had significantly worse cost-utility in both NoR and LowR cohorts (both p<.05). In ModR patients, BMP-2 usage had equivocal cost-utility ($680,532.35 vs $580,380.21, p=.14). In the HighR cohort, the cost-utility difference narrowed even further (BMP-2 use: $743,155.21 vs $719,628.79, p=.82).
CONCLUSION(S): Our study shows BMP-2 has equivocal cost-utility within those at moderate and high risk for developing pseudarthrosis within two years following spinal deformity correction. The generated predictive score can better aid spine surgeons assess risk and enhance justification for the use of BMP-2 during surgical intervention for adult spinal deformity. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Pelvic incidence (PI) serves as the cornerstone for many deformity classifications and realignment schema to create a more individualized realignment target for each patient. Yet, previous literature has linked high PI to problematic outcomes following corrective surgery, including mechanical complications and hip pathologies. PURPOSE: Investigate if patients with high pelvic incidence have increased risk for complications and poor clinical outcomes following ASD surgery. STUDY DESIGN/SETTING: Retrospective. PATIENT SAMPLE: A total of 689 ASD patients. OUTCOME MEASURES: Clinical Outcomes (ODI, SF-36 PCS, MCS), mechanical failure, surgical details.
METHOD(S): ASD patients with 2-year (2Y) data included. Groups: PI >65degree (HighPI) versus PI < 65degree (NormPI). Means comparison tests assessed differences in demographics, surgical details and outcomes between groups. Multivariate analysis controlling for baseline age, frailty, baseline PI-LL, and history of prior fusion, analyzed complication rates and clinical improvement between groups.
RESULT(S): Included: 445 ASD patients. There were 94 (21%) patients presented with a BL pelvic incidence greater than 65degree (HighPI). HighPI patients were older (63 yrs), shorter, with higher BMI and frailty (all p<.05). HighPI were more likely to have had a prior fusion (OR: 1.9, [1.2-3.1]). HighPI were more likely to present with lower physical functioning scores, and severe pelvic compensation (OR: 5.5, [3.4-8.9]) and global deformity (OR: 3.5, [2.2-5.6]). During surgery, HighPI underwent more 3COs (OR: 1.8,[1.1-3.1]) and fusion to pelvis (OR: 2.1,[1.1-3.9]). Upon correction, adjusted analysis revealed HighPI were more likely to be undercorrected in each age-adjusted parameter compared to LowPI (OR: 4.8, [2.9-7.8]). Yet, HighPI patients were less likely to deteriorate within in-construct PI-based alignment (relative lordosis and lordosis distribution) (OR: 0.3,[0.1-0.9]). While not different at six weeks, HighPI were more likely to deteriorate in PI-based global alignment and pelvic compensation from six weeks to two years (OR: 3.2, [1.6-6.5]). This translated to a higher likelihood of developing a major or mechanical complication by 2Y (OR: 1.6, [1.04-2.6]) via adjusted analysis.
CONCLUSION(S): High pelvic incidence is associated with increased frailty, decreased physical functioning, and more severe lumbopelvic and global deformity upon presentation for adult spinal deformity correction. These patients are more often undercorrected by age-adjusted standards and deteriorate in out-of-construct alignment over time even when adequately corrected, leading to higher mechanical complications by two years. Despite our focus on PI-adjusted alignment, we have still not optimized treatment for the patient with high pelvic incidence. Further research should target which surgical techniques and strategies can achieve better results in this population. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Operative intervention for adult spinal deformity (ASD) is associated with high rates of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). Multiple attempts have been made to guide realignment for ASD corrective surgery, yet the predominance have been based on functional gains, which may or may not directly impact such junctional malcompensation. PURPOSE: To assess impact of baseline patient deformity and surgical realignment on rates of PJK and PJF. STUDY DESIGN/SETTING: Retrospective study of patients prospectively enrolled in a single center ASD database. PATIENT SAMPLE: A total of 298 ASD patients. OUTCOME MEASURES: Proximal junctional kyphosis (PJK); proximal junctional Failure (PJF).
METHOD(S): ASD patients with 2-year (2Y) data, UIV above L1 and LIV at S1 or pelvis were included. Those with evidence of PJK at 6-weeks postoperatively were excluded. Six-week radiographs were used to assess alignment by 5 published alignment systems: SRS-Schwab, GAP Score, age-adjusted (AA), Roussouly (Rous), and the newly published sagittal age-adjusted score (SAAS). To compare the impact of each alignment system on rates of PJK and PJF by level of baseline deformity, all radiographic measurements used to calculate SRS-Schwab, AA, Rous, GAP and SAAS were re-scaled from 0 to 100 using the min-max of the cohort for each respective angle. Normalized values were then summed to compute a composite "deformity score" for each patient. Patients were ranked by deformity score into 3 groups: mild, moderate, and severe. Means comparison tests were used to assess rates of PJK and PJF (defined as PJK with reoperation) by alignment system in the cohort and by deformity group. Multivariate logistic regressions controlling for covariates such as age, PJK prophylaxis, and osteoporosis were used to generate odds ratios (OR) and identify the alignment systems associated with lower odds of developing PJK and PJF.
RESULT(S): A total of 298 patients met inclusion (62.5yrs, BMI: 27.5kg/m², CCI: 1.5, 76% F). Overall, 33.6% of the cohort developed PJK and 6.7% developed PJF. MVA of the cohort found those aligned to AA had a 55% lower odds of PJK (OR: 0.453, [0.283, 0.727], p=.001) and 60.4% lower odds of PJF (OR: 0.396, [0.169, 0.933], p=.034). Subanalysis of patients presenting with mild deformity scores (N=71) found none of the alignment systems reduced odds of PJK or PJF (all p>.05). Subanalysis of patients presenting with moderate deformity scores (N=108) found those meeting AA had 79% lower odds of PJK (OR: 0.210, [0.072, 0.615], p=.004), yet none of the alignment systems significantly reduced odds of PJF. In those severe deformity scores (N=119), meeting Schwab significantly reduced odds of PJK (OR: 0.492, [0.318, 0.761], p=.001). With regard to PJF, in those with severe deformity scores, alignment to Schwab (OR: 0.235, [0.104, 0.532], p=.001) and AA significantly reduced odds of PJF (OR: 0.352, [0.124, 0.994], p=.049).
CONCLUSION(S): This study aimed to assess impact of realignment to published systems on rates of PJK and PJF in surgical correction of adult spinal deformity. Overally, those meeting age-adjusted alignment had lowest rates of PJK and PJF. Morover, further analysis revealed that moderately and severely deformed patients beneit benefit from realignment to age adjusted criteria. However, none of the alignment systems were associated with lower odds of PJK or PJF in those presenting with mild deformity. This may indicate a certain level of PJK and PJF is not preventable by optimal realignment alone. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Thoracic decompensation (TD) represents a distinct radiographic complexity from proximal junctional kyphosis (PJK). Few studies exist on the occurrence of TD following adult spinal deformity (ASD) corrective surgery. PURPOSE: To assess the incidence of TD following ASD-corrective surgery in comparison with the occurrence of PJK. STUDY DESIGN/SETTING: Retrospective cohort. PATIENT SAMPLE: A total of 689 ASD patients. OUTCOME MEASURES: ASD, TD, PJK, thoracic compensation.
METHOD(S): ASD patients with complete baseline (BL) and two-year (2Y) followup were included. Patients were divided into groups: those who developed TD: T4-T12 >54.2degree and those who developed PJK. Further analysis assessed outcomes among patients with both TD and PJK (TDPJK). Thoracic compensation was defined as expected thoracic kyphosis minus BL thoracic kyphosis. Means comparison tests and multivariable logistic regression analysis assessed differences between patient groups.
RESULT(S): A total of 373 patients met inclusion criteria. Patient breakdown by radiographic outcome was: TD (N=31), PJK (N=223) and TDPJK (N=119). Age, gender, and ASD-mFI were similar between TD and PJK patients. TD patients were more likely to be osteoporotic than PJK patients, p < 0.05. Procedures on TD patients were less invasive and utilized a shorter construct (9.3 vs 11.5 levels; both p < 0.05). TD patients had significantly greater cervical lordosis, thoracic kyphosis, and lumbar lordosis than PJK patients at BL and 2Y follow-up, all p < 0.05. Thoracic compensation was significantly associated with TD (OR 1.07 [CI 1.04-1.09], p < 0.001) controlling for age, ASD-mFI, and invasiveness. TDPJK had the highest complication rate (84.9%), significantly greater than PJK patients (70.9%), and TD patients (61.3%), both p < 0.05. PJK patients were 78.7% less likely to develop PJF than TDPJK patients (OR 0.213 [CI 0.101-0.453], p < 0.001).
CONCLUSION(S): Patients who developed thoracic decompensation were more likely to present with osteoporosis, but had less invasive procedures and levels fused than patients with proximal junctional kyphosis. The tradeoff between fusing too much resulting in proximal junctional kyphosis and fusing too little predisposing to thoracic decompensation can serve as the basis of future studies to determine optimal construct length to balance these two risks. Thoracic compensation was predictive of postoperative thoracic decompensation in adult spinal deformity-correction. Patients who developed TDPJK had the highest rate of complications and greater odds of junctional failure. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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PURPOSE/OBJECTIVE:To develop age- and BMI-adjusted alignment targets to improve patient-specific management and operative treatment outcomes. METHODS:Retrospective review of a single-center stereographic database. ASD patients receiving operative or non-operative treatment, ≥ 18y/o with complete baseline (BL) ODI scores and radiographic parameters (PT, SVA, PILL, TPA) were included. Patients were stratified by age consistent with US-Normative values (norms) of SF-36(< 35, 35-55, 45-54, 55-64, 65-74, ≥ 75y/o), and dichotomized by BMI (Non-Obese < 30; Obese ≥ 30). Linear regression analysis established normative age- and BMI-specific radiographic thresholds, utilizing previously published age-specific US-Normative ODI values converted from SF-36 PCS (Lafage et al.), in conjunction with BL age and BMI means. RESULTS:486 patients were included (Age: 52.5, Gender: 68.7%F, mean BMI: 26.2, mean ODI: 32.7), 135 of which were obese. Linear regression analysis developed age- and BMI-specific alignment thresholds, indicating PT, SVA, PILL, and TPA to increase with both increased age and increased BMI (all R > 0.5, p < 0.001). For non-obese patients, PT, SVA, PILL, and TPA ranged from 10.0, - 25.8, - 9.0, 3.1 in patients < 35y/o to 27.8, 53.4, 17.7, 25.8 in patients ≥ 75 y/o. Obese patients' PT, SVA, PILL, and TPA ranged from 10.5, - 7.6, - 7.1, 5.8 in patients < 35 y/o to 28.3, 67.0, 19.15, 27.7 in patients ≥ 75y/o. Normative SVA values in obese patients were consistently ≥ 10 mm greater compared to non-obese values, at all ages. CONCLUSION/CONCLUSIONS:Significant associations exist between age, BMI, and sagittal alignment. While BMI influenced age-adjusted alignment norms for PT, SVA, PILL, and TPA at all ages, obesity most greatly influenced SVA, with normative values similar to non-obese patients who were 10 years older. Age-adjusted alignment thresholds should take BMI into account, calling for less rigorous alignment objectives in older and obese patients.

BACKGROUND CONTEXT: Advancements in artificial intelligence (AI), machine learning, and minimally-invasive (MIS) technique may offer enhanced preoperative planning, intraoperative robotic or navigational guidance, and prediction of postoperative complications for adult spinal deformity patients. Despite relatively widespread utilization, few studies in the literature assess the clinical and radiographic impact of AI in MIS surgery. PURPOSE: To assess the impact of artificial intelligence on peri- and postoperative course in minimally-invasive adult spinal deformity corrective surgery. STUDY DESIGN/SETTING: Retrospective cohort review. PATIENT SAMPLE: This study included 524 MIS patients. OUTCOME MEASURES: Intra- and postoperative complication rates; reoperation rate; HRQLs METHODS: Operative cervical deformity patients 18 years old with complete pre-(BL) and up to 2-year (2Y) postop radiographic/HRQL data were stratified by primary utilization AI-based patient-specific rod customization and robotic or navigational assistance in pre- and perioperative course (AI+) or not (AI-). Differences in demographics, clinical outcomes, radiographic alignment targets, perioperative factors and complication rates were assessed via means comparison analysis. Analysis of covariance (ANCOVA) assessed postoperative complications while controlling for BL age and gender.
RESULT(S): A total of 133 MIS patients were included (51.74+/-11.59 years, 41% female, 30.85+/-6.93 kg/m²). Of these patients, 44 (33.1%) were classified as AI+. At baseline, patient groups were comparable in BL age, BMI and CCI (all p>.05), though AI+ patients were more likely to be male (p=.040). Patient groups were comparable in terms of both regional and global radiographic alignment, as well as HRQLs at BL (all p>.05). Surgically, AI+ patients had significantly shorter operative times overall (p=.022) and decreased EBL (p=.001), as well as decreased likelihood of undergoing corpectomy (p=.001). Furthermore, AI+ patients reported significantly lower hospital LOS vs AI- patients (p=.012). At 2 years postoperatively, AI+ patients with custom rods were noted to have significantly improved segmental alignment in terms of decreased pelvic tilt (S1PT) and pelvic incidence (S1PI) (both p <.001). Adjusted complications analysis revealed that AI+ patients were significantly less likely to experience any postoperative complication (p=.003), neurological complications (p=.021) or complication requiring reoperation (p=.003).
CONCLUSION(S): Artificial intelligence and machine learning technologies may provide a substantial benefit to patients undergoing minimally-invasive adult spinal deformity surgery. The findings in this study demonstrate that patients operated on using AI-based robotic or navigational guidance, as well as the utilization of customized instrumentation, may reduce intraoperative invasiveness, shorten hospital length of stay, and decrease complication rates. As such, surgeons should consider utilization of AI-based technology in practice. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: The durability of adult spinal deformity (ASD) surgery is key for cost-effective treatment. Malalignment is one of the main reasons for revision surgery. PURPOSE: To investigate risk factors for loss of correction within the instrumented lumbar spine following ASD surgery. STUDY DESIGN/SETTING: Retrospective cohort study of a prospective database. PATIENT SAMPLE: This study included 321 ASD patients with minimum 3 -year follow-up. OUTCOME MEASURES: L1-S1, L4-S1 and L1-L4 lumbar lordosis.
METHOD(S): A total of 321 patients who underwent fusion of the lumbar spine (=5 levels, LIV S1/ilium) with a revision-free follow-up =3 years were identified. Patients were stratified by the change in PI-LL from 6 weeks to 3 years postop as Maintained vs Loss > 5degree. Those with a loss due to instrumentation failure (broken rod, screw pullout, etc.) were excluded before comparisons. Changes in regional and focal lordosis over time were investigated with repeated measures ANOVA and factor comparison.
RESULT(S): Mean age 64 yrs, BMI 28 kg/m², 80% female. The baseline alignment (PI-LL=21+/-19degree, T1PA=26+/-12degree) was corrected to PI-LL=3+/-13degree, and T1PA=18+/-10degree at 3 yrs (mean 3Y follow-up: 45+/-11m, with 44+/-11 mo between early and late follow-up). Eighty-two patients (25.5%) lost >5degree of PI-LL correction (mean loss 10+/-5degree). After exclusion of patients with instrumentation failure, 52 patients (Loss) with a mean loss of correction of 8.6+/-2.9 were compared to 222 controls with maintained LL correction. Demographics were similar between groups (age: 63 vs 61 p=0.15; Sex: 78.4% F vs 88.5% p=0.10). There were no significant differences in use of osteotomy, 3CO, and IBF between Loss and Maintained LL (all p >0.1). There was no significant difference in number of levels fused (11 vs 12 p=0.39), rod material (CoCr 59.4% vs 58.8% p=0.34), and BMP use (88.7% vs 84.6% p=0.41) but Loss had less supplemental rod use (5.8% vs 23.4% p=0.004). Comparison between Maintained and Loss revealed a similar PI-LL mismatch at pre-op (16.7+/-18.7 vs 20.9+/-18.3 p=0.14) and final postop (1.8+/-12.5 vs 5.1+/-14.5 p=0.11) but a significantly smaller PI-LL for Loss at early postop (0.6+/-12.8 vs -3.5+/-13.7 p=0.41). Distally, Maintained had a significant improvement in L4-S1 lordosis from preop to early postop (p=0.013), with no significant difference from early to final follow-up. In contrast, patients in the Loss group had no difference in L4-S1 from preop to early postop (p=0.14), but showed a significant loss of correction at 3 years (p <0.001). Proximally, significant increase between pre and early postop in L1-L4 (all p <0.001), with Loss and Maintained reaching similar early postop value (p=0.34). However, from early postop to final follow up, Loss showed a significant decrease in proximal lordosis (p <0.001) while Maintained did not (p=0.08), corresponding with a smaller absolute L1-L4 in the Loss cohort at 3 yrs (p=0.002). Screw orientation showed a significant decrease from early to late follow-up between the L1 and S1 screws for Loss (1.3+/-4.1 p=0.031), without any changes across the L4-S1 segment (-0.1+/-2.9 p=0.97).
CONCLUSION(S): Approximately a quarter of patients lose an average of 10degree of their 6-week correction by 3 years. Lordosis is lost proximally through the instrumentation (ie, tulip/shank angle shifts and/or rod bending), but lost distally through bone "settling" through the instrumentation itself. The use of supplemental rods and avoiding sagittal overcorrection may help mitigate this loss. 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) patients undergoing surgery risk neurological decline following surgery. However, surgery may be the key in improving outcomes in patients starting with lower extremity motor deficits at baseline (BL). We aim to analyze the improvement in neurological outcomes of ASD patients undergoing spinal reconstruction with BL and 6-week postoperative lower extremity motor scores (LEMS). PURPOSE: The aim of this study is to analyze the improvement in neurological outcomes of adult patients undergoing deformity surgery with baseline abnormal LEMS. STUDY DESIGN/SETTING: Multicenter, prospective cohort. PATIENT SAMPLE: A total of 205 patients were included in the study. OUTCOME MEASURES: Patient and procedural factors that lead to the improvement in neurological outcomes of adult patients undergoing deformity surgery with baseline abnormalLEMS.
METHOD(S): ASD patients ages = 18 were prospectively studied from 2018-2021. All patients underwent an instrumented PSF with a few also having an ASF of the lumbar spine. Patients were dichotomized based on BL LEMS (NML = 50, ABML < 50). The ABNML group was then dichotomized based on whether LEMS improved overall from BL or experienced no change or declined by first postoperative follow-up (PO) and various factors were analyzed and compared using standard statistical tests.
RESULT(S): Of the 205 patients evaluated, 134 (65.4%) were NML and 71 were ABNML (34.3%) at BL. Among the 71 patients with ABML LEMS at BL, 49% (N=35) improved to NML levels, 21% (N=15) improved from BL levels but not to NML, 20% (N=14) remained the same, and 10% (N=7) declined further at 6week PO. Compared to ABNML patients with no change or a decline in LEMS at first PO, patients who improved overall (70%; N=50) had significantly more decompressions performed (86% vs 57%; p=0.0092), and had more PCOs performed intraoperatively (90% vs 62%, p=0.0074). There were no statistical differences between the groups in age, BL LEMS, BMI, total instrumented vertebrae (TIV), EBL, and OR time. Overall, the number of patients with NML LEMS at 6 weeks PO increased by 7.5% (65.4% to 70.2%; p<.0001).
CONCLUSION(S): Seventy percent of patients with ABML LEMS at BL improved their motor strength by the first PO visit, while 30% stayed the same or declined. ABNML patients who improved from BL had significantly more decompressions performed and, surprisingly, more PCOs performed. Interestingly, patient factors between the two groups demonstrated no statistical differences further highlighting that improvement may be influenced by the differences in surgical techniques. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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