Association between duration of neurosurgical craniotomy and surgical site infection: a prospective cohort study

To quantify the dose-response relationship between the duration of neurosurgical craniotomy and the risk of surgical site infection (SSI) and to provide high-level evidence for optimizing perioperative infection prevention strategies.

A prospective cohort study was conducted among patients who underwent neurosurgical craniotomy in a tertiary grade A hospital from January 2021 to December 2022. Demographic data, underlying diseases, perioperative variables, and postoperative SSI outcomes were collected. Patients were divided into the SSI group (N = 68) and non-SSI group (N = 1197) based on the occurrence of SSI. Sample size was calculated using PASS software (version 15.0) with the following parameters: assumed SSI incidence of 5%, expected odds ratio (OR) of 1.2 for each 1-h increase in surgical duration, α = 0.05, and 1-β = 0.8, confirming that 1265 participants provided sufficient statistical power. Multi-variate logistic regression models (adjusted for confounding factors in three steps) were used to evaluate the association between surgical duration and SSI. Subgroup analyses were performed to explore potential effect modifiers. Restricted cubic spline (RCS) curves were applied to characterize the dose-response relationship.

A total of 1265 eligible patients were enrolled, with an overall SSI incidence of 5.38% (68/1265). During follow-up, 63 patients were lost to follow-up (loss rate = 4.98%, <20%), mainly due to patient relocation (N = 37) and refusal to continue follow-up (N = 26). All patients were included in the analysis, with missing outcome data handled by multiple imputation. Multi-variate logistic regression analysis showed that each 1-h increase in surgical duration was associated with a 19.6% increased risk of SSI (adjusted OR = 1.196, 95% confidence interval: 1.093-1.308, P < 0.001). Subgroup analyses revealed that this positive association was consistent across subgroups stratified by age, sex, hypertension, diabetes, and smoking history (all P for interaction > 0.05). RCS curves confirmed a significant linear dose-response relationship between surgical duration and SSI risk (P for overall < 0.001, P for nonlinear = 0.104), even after adjusting for all potential confounders.

Surgical duration is an independent risk factor for SSI after neurosurgical craniotomy, with a significant linear association. Shortening surgical duration via optimized surgical planning (e.g. pre-operative 3D reconstruction of skull lesions), improved surgical team collaboration (e.g. reducing instrument change time), and application of minimally invasive techniques (e.g. keyhole craniotomy), combined with strengthened perioperative infection control (e.g. strict sterile technique, intraoperative antibiotic redosing for surgeries exceeding 3 h) and optimized perioperative management (e.g. maintaining normothermia, avoiding unnecessary blood transfusion), may effectively reduce SSI risk and improve patient outcomes.