Abstract
Introduction
Incidence of deep surgical site infection (SSI) in spinal fusion varies from 0.3 to 20% according to the international literature. Instrumentation is a well-established risk factor for this complication. Higher morbidity and mortality rates and increased cost of treatment up to fourfold are associated with this complication. Prophylaxis with intravenous antibiotic is consensual, but few studies have evaluated the efficacy of topical agents in the surgical site with prophylactic intent. Irrigation with 3.5% povidone iodine and application of lyophilized vancomycin powder in surgical site have shown benefit, but there are no studies comparing these two methods. A comparative study using topic povidone iodine and vancomycin powder was conducted to reduce this knowledge gap.
Patients and Methods
The medical records of 439 patients who underwent spinal fusion with instrumentation for traumatic spinal lesion treatment were analyzed. Procedures were consecutively performed at Joao XXIII Hospital (level 1 trauma center). Patients were combined in the following two groups, according to the prophylactic agent used: Povidone iodine (PVPI) historical series (n = 181), performed from January 2009 to April 2012 and vancomycin (VANCO) cohort study (n = 239) conducted from May 2012 to December 2013. The surgical site in PVPI group was irrigated with 5% topic iodine solution during 3 minutes, before deep lumbar fascia closure. One gram of vancomycin powder was applied directly to the hardware in VANCO group. Both the groups received 2 g of intravenous cefazolin 30 minutes before surgery and had surgical site exhaustively washed with saline 0.9%, before closure in PVPI group and prior to apply vancomycin powder in VANCO group.
Results
No difference according to mean age, sex, and lesion level distribution (cervical × thoracolumbar) was observed between the two groups. Number of levels instrumented, coexisting infection, and surgical access were not compared because of a lack of information in medical records, especially those from PVPI series. SSI rate was lower in VANCO group (1.67%) compared with PVPI group (6.62%), this difference was statistically significant (chi-square test with Yates correction = 5.618; p = 0.018; IC 0.069–0.824).
Conclusion
The application of 1 g vancomycin powder in surgical site was superior to irrigation with 5% povidone iodine in the prophylaxis of deep surgical site infection. These results are valid for patients with spinal trauma who underwent instrumented fusion. Variability in surgical team, difference in the interval admission surgery (patients recently are being operated earlier), and number of levels instrumented are possible bias to this study. The low cost and easy applicability of topic prophylactic measures justify new studies with better statistical power (multicenter and randomized).