Comparative outcomes of gram-positive and gram-negative intraoperative infections in degenerative scoliosis: a 10-year propensity score-matched analysis

Purpose In this study, we examine the characteristics of Gram-negative and Gram-positive infections following scoliosis corrective surgery, as well as the potential risk factors contributing to infection. Methods We queried the Scoliosis Research Society (SRS) database from 2013 to 2023 to identify patients with degenerative scoliosis who developed postoperative infections. To account for comorbidities and minimize bias, 1:1 propensity score matching with replacement was performed. The total cohort sample was 706 (353 in each group), with 64% being female and a mean age of 67.9 years. The outcomes analyzed included infection duration, presence of neurological deficits, and mortality. Results Gram-negative infections had higher rates of return to the operating room (95.2% vs 74.5%, p < 0.001), and re-insertion of instruments (10.5% vs 4.5%, p = 0.004). However, Gram-positive bacteria were associated with higher rates of antibiotic-related complications (4.3% vs 1.1%, p = 0.02). Conclusion Gram-positive infections were associated with prolonged infection courses and higher mortality, while Gram-negative infections more often resulted in a return to surgery and neurological deficits. These findings suggest that Gram staining may provide an early and clinically meaningful distinction in risk stratification for patients with postoperative wound infections following scoliosis surgery.