Faculty Bibliography

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: Surgical correction of adult spinal deformity (ASD) has been associated with superior alignment and functional outcomes. However, postoperative complication rates remain relatively high. The extent to which potentially modifiable patient-related factors can influence complication rates in adult spinal deformity patients has not been effectively evaluated. PURPOSE: Evaluate the association between modifiable patient-related factors on complications following ASD corrective surgery. STUDY DESIGN/SETTING: Retrospective. PATIENT SAMPLE: A total of 689 ASD patients. OUTCOME MEASURES: Complication and reoperation rates.
METHOD(S): ASD patients with 2-year (2Y) data were included. Complication groups were defined as follows: 1) any complication; 2) major; 3) medical (cardiac event, ileus, etc.); surgical (site infection, wound dehiscence, etc.); 5) major mechanical (implant failure, rod fracture); 6) major radiographic (PJF [proximal junctional failure], pseudarthrosis, adjacent segment disease); and 7) reoperation. Modifiable risk factors included current smoker, obesity (BMI >30kg/m²), osteoporosis, alcohol use, depression (BL SF-36 MCS <35, perMatcham), psychiatric diagnosis and hypertension. Patients were stratified by BL deformity severity in T1PA (LowDef/HighDef) and age above or below 65 (Young/Older). Means comparison tests assessed prevalence of modifiable risk factors present in those developing specified complications. Binary logistic regression analysis was used to adjust for confounders.
RESULT(S): A total of 480 ASD patients met inclusion criteria (age 59+/-15 yrs, 77%F, BMI 27+/-5 kg/m², CCI: 1.7+/-1.7). By 2Y, comp rates: 72% one complication, 28% major, 21% medical, 27% surgical, 11% major radiographic, and 8% had a major mechanical complication. A total of 106 patients (22%) required reoperation. Overall, 318 patients (66%) had at least one of the preoperative risk factors. Age-Deformity Groups: 32% Young LowDef, 19% Young HighDef, 18% Older LowDef, 31% Older HighDef. Within Young LowDef, patients with osteoporosis were more likely to suffer either a major mechanical or radiographic comp (both OR >6, p<.05), although this trend was not seen in the overall cohort. Young HighDef patients were much more likely to develop complications if obese, especially major mechanical complications (OR: 2.8, [1.04-8.6]; p=.045), while patients with depression or a psychiatric diagnosis suffered major radiographic comps and underwent reoperation more often. Older patients with HighDef developed significantly more complications when diagnosed with depression, including major radiographic comps (23% vs 8%, OR: 3.5, [1.1-10.6]; p=.03). Overall, when controlling for baseline deformity, frailty, and osteoporosis, a diagnosis of depression proved to be a significant risk factor for development of major radiographic complications (OR: 2.4, [1.3-4.5]; p=.005).
CONCLUSION(S): Certain modifiable patient-related factors, especially mental health status, are associated with increased risk for complications following spinal deformity surgery. Therefore, with consideration to clinical presentation, elaborate on the utility in medical intervention prior to undergoing spinal deformity corrective surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Adaptation of age-adjusted alignment has gained popularity for its correlation with clinical improvement and lowering rates of proximal junctional kyphosis. Age-adjusted parameters correlate with outcomes. However, frailty may be a better predictor of each following ASD surgery. PURPOSE: To adjust the Sagittal Age-Adjusted Score (SAAS) to accommodate frailty in alignment considerations will increase the predictability of clinical outcomes and junctional failure. STUDY DESIGN/SETTING: Retrospective. PATIENT SAMPLE: A total of 689 ASD Patients. OUTCOME MEASURES: Mechanical complications, PJF, PJK and ODI.
METHOD(S): Included: surgical ASD pts with 2Y data. Frailty assessed by ASD modified Frailty Index (ASD-mFI).
Outcome(s): proximal junctional kyphosis (PJK) and failure (PJF), major mechanical complications, and Smith et al Best Clinical Outcome (BCO), defined as ODI 4.5. Linear regression analysis established a 6W score based on SAAS component scores, frailty and ODI US norms per published by Lafage et al. Logistic regression followed by conditional inference tree (CIT) analysis generated categorical thresholds. Logistic regression analysis controlling for age, baseline deformity and revision status generated odds ratios for the continuous score. Thirty percent of the cohort was used as a random sample for internal validation.
RESULT(S): There were 412 pts included. BL frailty categories: 57% not frail, 30% frail and 14% severely frail. Overall, by 2Y, 39% of patients developed PJK, 8% PJF, 21% mechanical complications, 22% underwent reoperation and 15% met BCO. SAAS only correlated with development of PJF. The ASD-mFI demonstrated correlation with all outcomes except PJK (all p1.4, offset: 0.75-1.4, sseverely offset:.05). Internal validation saw these outcomes maintain significance between categories, with significant adjusted correlation to meeting BCO (OR: 3.8, 1.1-13.5; p=.037).
CONCLUSION(S): Consideration of physiologic age, in addition to chronological age, may be beneficial in management of operative goals to maximize clinical outcomes while minimizing junctional failure. This combination enables the spine surgeon to fortify a surgical plan for even the most challenging patients undergoing adult spinal deformity surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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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: Recent literature has pointed to the rising use of prone lateral versus lateral decubitus positioning in minimally invasive spine surgery (MISS) as a method to reduce operative time, increase patient safety, and aid in surgical accessibility. However, there is a paucity of literature as to how prone lateral and lateral decubitus positioning compares in terms of reaching optimal postoperative outcomes and reducing complication rates. PURPOSE: To assess differences between prone lateral and single-position lateral decubitus positioning compares in terms of reaching optimal postoperative outcomes and reducing complication rates. STUDY DESIGN/SETTING: Retrospective review of prospective MIS database. PATIENT SAMPLE: A total of 524 MIS patients. OUTCOME MEASURES: HRQLs; complications; surgical factors.
METHOD(S): MISS patients with BL) and 2-year(2Y) postop radiographic/HRQL data were included. Patients positioned in the prone latera (PL) or single-position lateral decubitus (LD) position were isolated. At 2Y, an optimal outcome score was calculated using 4 equally weighted criteria: 1) achieving ideal PT per SRS-Schwab at 2Y, 2) Achieving ideal PI-LL per SRS-Schwab at 2Y, 3) No complication requiring reoperation, 4) Achieving NRS MCID by Salaffi et al. criteria; optimal score threshold was set at meeting 2 of 4 criteria. Means comparison analysis assessed differences in radiographic and clinical outcomes at BL and 1Y postoperatively. ANCOVA assessed estimated marginal means adjusting for BL age and revision status.
RESULT(S): Thirty-four PL and 36 LD patients were included (54.40+/-12.49 years, 40% female, 30.93+/-6.52 kg/m2, mean CCI: 2.23+/-1.55) were included. At baseline, patients were comparable in age, gender, BMI and CCI (all p>.05). Perioperatively, PL patients demonstrated significantly lower operative time (200.09 vs 284.54 min, p=.007) and EBL (332.35 vs 192.05 mL, p=.027). Though optimization scores were equivalent between groups (p=.160), PL patients demonstrated significantly lower perioperative complication rates (p=.012), neurological complication rates (p=.006), and had a fewer number of total complications by 2Y (p=.014). When controlling for BL age and revision status, the PL patients demonstrated consistently fewer intra- and perioperative complications as well (both p<.015). In terms of patient-reported outcomes, PL patients also demonstrated significantly improved NRS-Leg scores compared to LD patients by 1Y (p=.038).
CONCLUSION(S): Patients placed in the PL position during minimally-invasive adult spinal deformity surgery demonstrate decreased mean operative times and decreased intraoperative invasiveness and blood loss versus patients operated on via single-position LD positioning. Though overall rates of achieving optimal outcome remain comparable, PL approach should be considered as there may be significant additional benefit in reducing peri- and postoperative complications by 2Y. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: As surgical techniques for deformity correction evolve towards minimizing tissue trauma, further clarity is warranted to define differences in complication profiles between cMIS and open surgeries. PURPOSE: To compare cMIS and open surgery reoperation rates and identify contributing etiologies to reoperation in each cohort. STUDY DESIGN/SETTING: Prospective multicenter observational series. PATIENT SAMPLE: Database enrollment required age =18 years, adult spinal deformity and circumferential minimally invasive spine surgery. OUTCOME MEASURES: Reoperation rate, patient reported outcomes (PROMS), spinopelvic parameters, mechanical failures (defined as rod breakage/dislocation, screw breakage/loosening, set screw loosening, proximal/distal junctional kyphosis, pseudoarthrosis) and other factors contributing to re-operation such as wound infection, medial breach, nerve impingement by screw, vertebral body fracture, sagittal/coronal imbalance, and wound infection.
METHOD(S): A total of 85 patients (pts) with cMIS for ASD with 2-year follow-up (2YFU) were identified and propensity matched to 85 patients in open cohort. Propensity matching was performed based on pre-operative PT, PI-LL, BMI, and SVA. Patient demographic variables, reoperation rate, and complications contributing to reoperation were compared with uni- and multi-variate analysis at any time in each cohort (33 open, 17 cMIS). PROMS at 2YFU were compared in the reoperated cohorts.
RESULT(S): Total of 33 reoperation in the open cohort vs 17 in cMIS were identified. The reoperation rate was significantly higher in the open cohort at 39% (33/85) compared to 20% (17/85) in the cMIS cohort (P= 0.012). The reoperation rate in open cohort related to mechanical failure was 52% (17/33) compared to 35% (6/17) in cMIS cohort (P= 0.43). No significant difference was found in rates of specific etiologies contributing to complications in the cMIS vs open reoperation cohorts under uni- and multivariate analysis. The change in spinopelvic parameters among the two reoperation cohorts at 2YFU were statistically not significant (deltaCVA, deltaSVA, deltaPI-LL, deltaPT, deltaLL CA, deltaTL CA). Under univariate analysis, the following PROMS were similar: ODI, NRS Leg and Back Pain, EQ5D, EQ5D-VAS, SF-36 PCS,SF-36 MCS. However, SRS-22 in open cohort was significantly higher at 2YFU (3.55 +/- 0.73 open vs. 3,10 +/- 0.56 MIS, p = 0.029).
CONCLUSION(S): Findings in our ongoing study show that cMIS procedures were associated with a significantly lower reoperation rate compared to open surgical approaches. PROMS and the change in spinopelvic parameters were similar at 2YFU in both reoperated cohorts (except for SRS-22 favored open cohort). 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: Adult spinal deformity (ASD) patients maintain upright posture by compensating through their spine, pelvis and lower extremities. Little data exist quantifying the contribution of lower extremity compensation through the hips, knees, and ankles to maintain upright posture. PURPOSE: Evaluate the effect of the lower limb compensation by numerically unfolding patients. STUDY DESIGN/SETTING: Multicenter, prospective cohort. PATIENT SAMPLE: A total of 288 patients surgically treated for complex ASD with preoperative full body images. OUTCOME MEASURES: Horizontal distance between vertebra centroid and ankle.
METHOD(S): Surgical ASD patients were enrolled into a prospective 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 age (>65 and >7 levels fused). Preop full-body images were evaluated and age and PI-adjusted normative values were used to model spine alignment based upon three configurations: COMP (all lower extremity compensatory mechanisms maintained), PARTIAL (removal of ankle dorsiflexion and knee flexion, maintained hip extension), UNCOMP (ankle, knee, and hip compensation eliminated by reset PT to the age and PI norms). The three configurations were compared, and COMP alignment was stratified by TPA percentiles to investigate the offsets from each vertebra to the ankle joint acting as a surrogate of the gravity line in free-standing position.
RESULT(S): A total of 288 patients met inclusion criteria (60+/-15yo, 70.5% female, 27.4+/-5.9 BMI). COMP spine deformity magnitude included PI-LL 15+/-24, TPA 24+/-14, and SVA 65+/-69mm. As the model transitioned from COMP to UNCOMP alignment, the initial posterior translation of the pelvis decreased significantly to an anterior translation vs the ankle (P.Shift 30 to -7.6 mm). This was associated with a decrease in pelvic retroversion (PT 24.1 to 16.1), hip extension (SFA 203 to 200), knee flexion (KA 5.5 to -0.4), and ankle dorsiflexion (AA 5.3 to 3.7). As a result, the anterior malalignment of the trunk significantly increased SVA (65 to 120mm) and G-SVA (C7-Ankle from 36 to 127 mm), leading to a three-fold increase in bending moments sustained by the ankle joint. The stratification of the COMP position by TPA percentiles revealed that as the deformity increases, the vertebrae above T8 translate anteriorly, those below T10 move posteriorly, with the T8-T10 segment remaining ~3cm posterior to the ankle joint independently of the deformity severity.
CONCLUSION(S): Removal of lower limbs' compensation revealed an unsustainable truncal malalignment with a three-fold increase of bending moments at the ankle joints. Combined, lower limb compensations permit "reducing" the SVA by two-fold and the C7-ankle SVA by three-fold. From a mechanical point of view, this compensation permits maintaining the trunk center of mass (T9) at a fixed offset of ~3 cm from the ankle joint. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: 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. PURPOSE: 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. STUDY DESIGN/SETTING: Retrospective cohort study of a prospective adult spinal deformity (ASD) database. PATIENT SAMPLE: A total of 1,541 patients. OUTCOME MEASURES: Cost-per-QALY, radiographic realignment, clinical outcomes.
METHOD(S): 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.
RESULT(S): 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.
CONCLUSION(S): 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. 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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