Complication rates are reduced for revision adult spine deformity surgery among high-volume hospitals and surgeons

Background context Revision adult spinal deformity surgery (RASDS) is a particularly high-risk intervention. Purpose The aim was to assess complication rates in RASDS by surgeon and hospital operative volume. Study design/setting This was a retrospective analysis of prospectively collected data. Patient sample Based on a Nationwide Inpatient Sample (NIS) database (2001-2010), patients aged older than 21 years (International Classification of Diseases, Ninth Revision, Clinical Modification) with spine arthrodesis for scoliosis were included. For longitudinal analysis, the 2008-2011 New York State Inpatient Database (NY SID) was queried. Outcome measures The outcome measures included complication rate after RASDS. Methods Cases were identified as primary or revision surgery with or without osteotomy performed. Annual surgeon and hospital volumes were stratified into quartiles via identifier codes. Case complexity was determined using a novel operative complexity index, based on available NIS operative parameters: levels fused, approach, osteotomy, and revision status. The primary end point was morbidity during the hospital stay. New York State Inpatient Database analysis allowed for identification of rate of reoperation for infection or pseudarthrosis/implant failure. One-way analysis of variance was used to assess continuous measures, chi-square for categorical measures. Results Of 139,150 adult spinal deformity surgery (ASDS) cases, 4,888 revision with hospital identifiers and 1,978 with surgeon identifiers were identified. Higher-volume surgeons performed more revision cases and cases requiring osteotomy. With increasing hospital volume, complication rate for RASDS decreased (9.7% vs. 12.9% at highest- vs. lowest-volume centers, p<.001). The highest-volume surgeons showed significant decreases in the rate of major complications for RASDS (8.8% vs. 10.7% for lowest-volume surgeons, p<.001). A similar trend was observed for ASDS cases requiring osteotomy. Multiple logistic regression analysis showed that the highest-volume hospitals and surgeons showed a reduced odds ratio for all complications compared with lowest-volume hospitals. For the NY SID, 528 RASDS cases indicated reoperation rates for infection and pseudarthrosis/implant failure after RASDS were increased for the lowest-volume hospitals and surgeons. Conclusions Perioperative complication rate associated with RASDS is lower when patients are treated by high-volume surgeons at high-volume centers. As complex cases requiring osteotomy and combined approaches are more frequent at high-volume centers, an operative complexity index helps predict the likelihood of volume-dependent complication rates. Future interhospital and intersurgeon comparisons should account for these case characteristics so that similar case complexity is compared in these analyses.