P90. External validation of the ESSG-ISSG calculator utilizing a single institutional experience for adult spinal deformity corrective surgery

• Published in: The spine journal Vol. 20; no. 9; pp. S189 - S190
• Main Authors: Passias, Peter G., Naessig, Sara, Ahmad, Waleed, Diebo, Bassel G., Raman, Tina, Lafage, Virginie, Lafage, Renaud, Smith, Justin S., Janjua, Muhammad B., Ames, Christopher P.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.09.2020
• ISSN: 1529-9430; 1878-1632
• DOI: 10.1016/j.spinee.2020.05.488

The International Spine Study Group (ISSG) and the European Spine Study Group (ESSG) developed an adult spinal deformity (ASD) specific risk calculator based on the largest and most granular, prospective ASD database. The calculators utilize preoperative radiographic, surgical, and patient-specific variables in order to predict patient-reported outcomes and complication rates at 2 years. Assess the ISSG-ESSG risk calculator usability in a single institution ASD population. Retrospective cohort study- single surgeon institution. ASD pts: A total of 631 patients undergoing surgery for adult spinal deformity. Improvement from BL SRS-22 [Pain, Function, total], major complications, Oswestry Disability Index (ODI). ASD pts were isolated in the single-center ASD Database 2013-2020. Frail pts were isolated (Frail[F] 0.3>0.5). Basic demographics were assessed for these F pts via chi-squared and t-tests. Each F patient was inputted into the ESSG risk calculator to identify individual predictive rates for postoperative 2-year HRQL outcomes as well as major complications. These calculated predicted outcomes were analyzed against those identified from the ASD database in order to validate the calculator predictability in a single center institution via Brier scores. Having a score closer to 1 means the EESG calculator is not predictive of that specific outcome. A score closer to 0 meant the EESG calculator was a predictive tool for that factor. A total of 631 ASD pts were isolated (55.8;16.8yrs, 26.68kg/m2, 0.95±1.3CCI). Of these patients, 7.8% were frail. Fifty percent of frail pts received an interbody fusion, 58.3% received a decompression, and 79.2% had an osteotomy. Surgical details: mean operative time 342.9±94.3minutes, mean estimated blood loss 2131.82±1011mL, and an average length of stay 7.12±2.5days. The EESG calculator predicted the likelihood of improvement for the following HRQL's ODI(86%), SRS-22 Mental Health (71.1%), SRS-22 Total (87.6%), major complication (53.4%). The single institution had lower percentages of improvement in ODI (24.6%), SRS-22 Mental Health (21.3%), SRS-22 Total (25.1%), and lower presence of major complication (34.8%). The calculated Brier scores identified the calculator's predictability for each factor: ODI (0.24), SRS-22 Mental Health (0.21), SRS-22 Total (0.25), major complication (0.28). The newly developed ESSG-ISSG risk-assessment tool has a wide application in single institutions as it accurately predicts 2-year outcomes for various SRS-22 questionnaires and development of major complications. This abstract does not discuss or include any applicable devices or drugs.