138. Radiographic malalignment has a far greater impact on clinical outcomes than perioperative and postoperative complications in ASD surgery

Abstract

BACKGROUND CONTEXT Corrective surgery for adult spinal deformity (ASD) is known to carry a high likelihood of complications including surgical site infection, mechanical failure and loss of correction. It is currently unclear what category of complications that has the greatest impact on outcomes following ASD surgery. PURPOSE To investigate what types of complications had the greatest impact on HRQL scores at two years following corrective surgery. STUDY DESIGN/SETTING Retrospective cohort study of a multicenter database of ASD patients. PATIENT SAMPLE This study included 762 patients. OUTCOME MEASURES Health related quality of life (HRQL) as measured by the SRS-22 and ODI. Methods Operative ASD patients (scoliosis ≥20°, SVA ≥5cm, PT ≥25°, or TK ≥60°) with available baseline and 2-year radiographic and HRQL data were included. Surgical outcomes at 2 years were the primary dependent variable and the type of major complication was the main predictor. Complications were stratified as intraoperative/perioperative, medical, mechanical, or neurological. Multivariable analysis controlling for age, CCI, baseline deformity, invasiveness, and baseline disability was used to assess the impact of complications on HRQL outcomes. A conditional inference tree (CIT) was used to stratify complications in a hierarchal manner based on the greatest impact on HRQL. Results A total of 762 ASD patients met inclusion criteria (59.9years±14.0, 79%F, BMI: 27.7 kg/m2 ±6.0, ASD-FI: 3.3±1.6, CCI: 1.8 ±1.7) with mean levels fused of 11.1±4.4 and 69.9% posterior-only, and 29.3% had a combined approach. Six complication categories were included: 245 (32.2%) were medical complications (including cardiopulmonary, renal, GI, musculoskeletal, nonsurgical infection); 135 (17.7%) were neurological (including radiculopathy, myelopathy, nerve root injury, motor or sensory deficit, bowel or bladder deficit, stroke); 545 (71.5%) were mechanical after discharge (implant malposition or dislocation, rod or screw breakage, PJF, PJK, implant prominence); 248 (32.5%) were intra/perioperative (including prolonged SICU, prolonged op time, dural tear); 317 (42%) were radiographic (remaining severe in Schwab SRS or worsening postoperatively unrelated to PJF); and 17 (2.2%) were surgical infection related complications. Multivariate analysis revealed which complication categories had a significant effect on ODI and SRS-total at 2 years. Through CIT ranking, malalignment was found to have the greatest negative effect on both ODI and SRS, followed by neurological complications. None of the other 4 categories led to significant long-term effects. Among the individual complications, CIT analysis ranked remaining severe in any SRS-Schwab modifier by 2 years as the largest contributor to worse outcomes in ODI and SRS at 2 years, followed by implant failure, development of a motor deficit, and PJF for ODI, and implant failure, PJF, and worsening in PILL postoperatively for SRS. Conclusions Despite a significant portion of patients experiencing intraoperative/perioperative, medical, mechanical, and many neurological complications, the most detrimental contributors to poor long-term outcomes were almost exclusively related to poor radiographic correction, loss of correction postoperatively, and mechanical failure. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. Corrective surgery for adult spinal deformity (ASD) is known to carry a high likelihood of complications including surgical site infection, mechanical failure and loss of correction. It is currently unclear what category of complications that has the greatest impact on outcomes following ASD surgery. To investigate what types of complications had the greatest impact on HRQL scores at two years following corrective surgery. Retrospective cohort study of a multicenter database of ASD patients. This study included 762 patients. Health related quality of life (HRQL) as measured by the SRS-22 and ODI. Operative ASD patients (scoliosis ≥20°, SVA ≥5cm, PT ≥25°, or TK ≥60°) with available baseline and 2-year radiographic and HRQL data were included. Surgical outcomes at 2 years were the primary dependent variable and the type of major complication was the main predictor. Complications were stratified as intraoperative/perioperative, medical, mechanical, or neurological. Multivariable analysis controlling for age, CCI, baseline deformity, invasiveness, and baseline disability was used to assess the impact of complications on HRQL outcomes. A conditional inference tree (CIT) was used to stratify complications in a hierarchal manner based on the greatest impact on HRQL. A total of 762 ASD patients met inclusion criteria (59.9years±14.0, 79%F, BMI: 27.7 kg/m2 ±6.0, ASD-FI: 3.3±1.6, CCI: 1.8 ±1.7) with mean levels fused of 11.1±4.4 and 69.9% posterior-only, and 29.3% had a combined approach. Six complication categories were included: 245 (32.2%) were medical complications (including cardiopulmonary, renal, GI, musculoskeletal, nonsurgical infection); 135 (17.7%) were neurological (including radiculopathy, myelopathy, nerve root injury, motor or sensory deficit, bowel or bladder deficit, stroke); 545 (71.5%) were mechanical after discharge (implant malposition or dislocation, rod or screw breakage, PJF, PJK, implant prominence); 248 (32.5%) were intra/perioperative (including prolonged SICU, prolonged op time, dural tear); 317 (42%) were radiographic (remaining severe in Schwab SRS or worsening postoperatively unrelated to PJF); and 17 (2.2%) were surgical infection related complications. Multivariate analysis revealed which complication categories had a significant effect on ODI and SRS-total at 2 years. Through CIT ranking, malalignment was found to have the greatest negative effect on both ODI and SRS, followed by neurological complications. None of the other 4 categories led to significant long-term effects. Among the individual complications, CIT analysis ranked remaining severe in any SRS-Schwab modifier by 2 years as the largest contributor to worse outcomes in ODI and SRS at 2 years, followed by implant failure, development of a motor deficit, and PJF for ODI, and implant failure, PJF, and worsening in PILL postoperatively for SRS. Despite a significant portion of patients experiencing intraoperative/perioperative, medical, mechanical, and many neurological complications, the most detrimental contributors to poor long-term outcomes were almost exclusively related to poor radiographic correction, loss of correction postoperatively, and mechanical failure.