Influence of perioperative complication severity on 1- and 2-year outcomes of low back surgery

James Grainger, Thomas Hammett, Robert Isaacs, Chad Cook

Several factors potentially influence outcomes of surgery, including perioperative complications. Complications may take many forms and the Clavien-Dindo (CD) classification is designed to categorize them by degree of severity. The aim of this study was to evaluate the influence of perioperative complications by severity categorization on the 1-and 2-year pain and disability outcomes for patients who received low back surgery. Data used for the study involved a purposive sample (N = 477; 8.1%) from a spine outcomes registry of 5876 patients who received spine surgery and encountered complications. All complications were categorized using the CD classification and were collapsed according to distribution frequencies, i.e., Grade I-II and Grade III-V. Adjusted and unadjusted regression analyses were used to determine the association between CD classification and 1- and 2-year outcomes. The majority of surgical complications were Grade III-V (N = 358; 75.1%), with two incidences in which death occurred. For the unadjusted models, there were no significant associations between CD classification categorizations for 1-year outcomes; however, 2-year outcomes were significantly worse (P <0.05) for those with Grade III-V categorization. When adjusted and controlled for baseline characteristics, CD classification did not influence 1-or 2-year pain and disability outcomes. When control variables are considered, the severity of perioperative surgical complications does not appear to influence 1- or 2-year pain and disability outcomes. Level 4.