Reply to "letter to the editor" by Baker and Chen regarding "Effectiveness of local vancomycin powder to decrease surgical site infections: a meta-analysis"

Surgical site infection following surgery for spinal deformity: About 102 patients

INTRODUCTION

Complex spinal surgery is known to be at risk of complications. Surgical site infection is a serious complication in spine surgery and its frequency is significantly increased in adult spinal deformity correction. The aim of this study is to identify patients' characteristics and risk factors of surgical site infection (SSI) following an osteotomy.

METHODS

This is a single-center retrospective study of patients who underwent an osteotomy between January 2015 and December 2017. Surgical site infection diagnosis was based upon patient's clinical evidence of infection, biologic parameters, microbiological criteria and/or image findings.

RESULTS

In total, 102 patients were eligible and 70 were women (68.6%). Mean age was 65 years old (27-83 years) and mean body mass index (BMI) was 26.14kg.m^-2 (18.4-44.1). Eleven patients were in the SSI group and 91 in the No-SSI group. The mean Schwab grade was 1.5 (1-4) in the SSI group vs. 1.4 (1-5) in the No-SSI group (P=0.435). The mean operative time was on 201.9 minutes (67-377). Mean length of stay was 20.6 days (10-73) in the SSI group vs. 15 days (5-44) in the No-SSI group (P=0.041). Favorable outcome was found in 10 patients (90.9%) in the SSI group.

CONCLUSION

Correction surgery for adult spinal deformity with osteotomies carries a high risk of complications specially SSI. Identification of risk factors, prevention and medical management of SSI should be well assessed.

Intrawound Vancomycin Powder Reduces Bacterial Load in Contaminated Open Fracture Model

OBJECTIVES

To compare the effectiveness of both vancomycin powder and antibiotic bead placement to irrigation and debridement alone in prevention of infection in a contaminated open fracture model in rats.

METHODS

In a previously described model of contaminated open fractures, 45 rats had simulated open fractures created, stabilized, and contaminated with Staphylococcus aureus. They were then treated 6 hours later with 3 interventions: irrigation and debridement alone (control group) or in combination with placement of polymethyl methacrylate beads containing vancomycin and tobramycin powders (antibiotic bead group) or placement of 10 mg of intrawound vancomycin powder (powder group). Rats were allowed to recover and then killed 14 days later for harvest of femurs and plates. Femurs and plates were both incubated overnight, and bacterial colonies were counted in each group for comparison.

RESULTS

Quantitative counts of bacteria in bone showed significantly reduced growth in both bead and powder groups when compared with control group (P < 0.0001). Quantitative counts of bacteria in plates showed significantly reduced growth in both bead and powder groups when compared with control group (P < 0.0003; 0.029). No significant differences were seen in bacterial growth between bead and powder groups for either bones (P = 0.13) or plates (P = 0.065).

CONCLUSIONS

When compared with irrigation and debridement alone, placement of intrawound vancomycin powder significantly decreased bacterial load in a contaminated open fracture model in rats similar to placing antibiotic beads. This may provide an additional adjuvant treatment that does not require a secondary surgery for bead removal.

Local Intra-wound Administration of Powdered Antibiotics in Orthopaedic Surgery

Surgical site infection (SSI) is one of the most common complications after orthopaedic surgery, leading to significant morbidity and its associated costs. Surgical guidelines strongly recommend the use of systemic antibiotic prophylaxis to reduce the risk for developing SSI. Locally administered powdered antibiotics have the potential to provide remarkably high intra-wound concentrations without risk for systemic toxicity. However, a paucity of high quality evidence in the orthopaedic literature has prevented widespread adoption of this technique. The majority of clinical studies on local intra-wound antibiotics have evaluated the use of topical powdered vancomycin in spinal surgery, though only a single prospective study currently exists. This review will discuss all the available evidence describing the effectiveness, pharmacokinetics, and potential adverse effects with the use of topical powdered antibiotics in orthopedic surgery.