Surgical site infection (SSI) occurs in 0.7%–12 % of patients after spinal surgery [1,2]. SSI is one of the most severe and persistent postoperative complications that continues to pose challenges to both patients and spine surgeons. SSIs result in in prolonged hospital stay and increased morbidity, mortality, and health care costs [1,2]. Numerous studies have identified the risk factors for SSI after spinal surgery, namely diabetes mellitus (DM), body mass index (BMI), male sex, previous surgical history, smoking, and operation time [[3], [4], [5], [6]]. Conversely, microendoscopy is a protective factor [7].

The influence of SSI on patient-reported outcomes (PROs) remains uncertain. Although several reports have investigated postoperative outcomes in patients with SSI after spinal surgery, the number of patients evaluated was small [[8], [9], [10], [11], [12], [13], [14], [15]]. When comparing surgical outcomes between patients with and without SSI, patients’ background characteristics, such as age, sex, DM status, or American Society of Anesthesiologists physical status classification (ASA-PS), could vary and must be statistically adjusted, which requires a high number of patients for enrollment. Furthermore, most previous studies evaluated retrospectively collected data at a single institution [8,9,12,13]. Therefore, we performed this multicenter cohort study of prospectively collected data to investigate whether the presence of SSIs affects PROs 1 year postoperatively, using propensity score matching analysis, and we identified the risk factors for SSI.