Incidence of complications following lumbar or lumbosacral fusion is still an imprecise notion. The aim of this prospective observational study was to determine the frequency of intraoperative and early postoperative complications after this procedure and to analyze favoring factors.

Twenty-one orthopedic units participated in this study which included 872 patients who underwent lumbar or lumbosacral fusion procedures involving the sector limited by L1 and S1. A minimum of 6 months follow-up was required for inclusion. Four types of complications were studied: general complications, infection, neurological and meningeal complications, mechanical problems. The following preoperative and intraoperative parameters were recorded: epidemiological and morphological data, history of lumbar spine surgery, comorbid conditions, indication for surgery, and technical aspects of the fusion. Two types of analysis were performed. The first was a descriptive analysis designed to determined the overall incidence of complications and the incidence of each type of complication. A multivariate analysis was then performed in order to determine factors influencing occurrence of complications.

Mean follow-up was 13 months, mean age of the cohort was 51 ± 15.5 years. Prior lumbar surgery was noted in 12% of the patients. A decompression procedure was associated in 40% of the patients due to lumbar stenosis. Posterolateral arthrodesis was used in 71% of the patients and 91% were instrumented. Most of the fusions were short, involving one or two levels. One or more intraoperative or early postoperative complications were observed in 200 patients (23%). The incidences of the four types of complications expressed in percent of the total cohort were 9.7%, 5.6%, 8.6%, and 3.6% for general, infectious, neurological and meningeal, and mechanical complications respectively. Three factors exhibited a significant correlation with occurrence of complications, irrespective of the type: excess weight, presence of several comorbid conditions, and extent of the zone of fusion.

This study enabled a precise assessment of the incidence of complications subsequent to lumbar or lumbosacral fusion: 23%. The incidence of serious complications requiring a reoperation was 14.7%. This finding, together with the factors found to influence occurrence of these complications should be kept in mind when determining indications for lumbar or lumbosacral fusion.