Surgical Duration Is Independently Associated with an Increased Risk of Surgical Site Infection and May Not Be Mitigated by Prolonged Antibiotics

Abstract

Background: Infection after tumor resection and endoprosthetic reconstruction is a potentially limb-threatening complication. The duration of surgery has been shown to be a risk factor for infection, but the ability of an extended duration of postoperative prophylactic antibiotics to potentially minimize that risk has not been specifically studied. The objective of this study was to determine whether extended postoperative antibiotic therapy protects against surgical site infection (SSI) in the setting of prolonged surgical duration in patients undergoing endoprosthetic reconstruction after tumor resection. Methods: This study was a planned secondary analysis of the Prophylactic Antibiotic Regimens in Tumor Surgery (PARITY) trial data set. Patients in the PARITY trial were randomized to receive 24 hours or 5 days of postoperative prophylactic antibiotics. The current study assessed the risk of SSI in those cohorts on the basis of surgical duration. A multivariable regression model was used to examine the adjusted effects of the duration of surgery on SSI, after controlling for other significant risk factors and potential confounders. Results: All 604 patients who had been included in the final data analysis in the PARITY trial were also included in this secondary analysis. Those who sustained an SSI had a greater mean duration of surgery (6.2 hours) compared with those who did not sustain an SSI (4.9 hours, p < 0.0001). There was no specific time point at which the risk of infection significantly increased. Extended postoperative prophylactic antibiotic therapy did not appear to mitigate the risk of SSI even in patients with prolonged surgical duration. Conclusions: Increased surgical duration was an independent risk factor for SSI in orthopaedic patients undergoing endoprosthetic reconstruction after tumor resection. However, surgical duration is multifactorial and is influenced by several variables. For example, there may be protective features of flap coverage that increase surgical duration while paradoxically decreasing the risk of SSI. Extended postoperative antibiotic therapy did not mitigate the risk of infection in this cohort, and other risk mitigation strategies will need to be considered in future studies. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.