The Use of Single Dose vs Short-Term Peri-Operative Cefazolin in the Prevention of Surgical Site Infection Following Orthognathic Surgery

Orthognathic surgery describes a group of procedures aimed at correcting developmental or acquired deformities of the jaws and facial skeleton. The goal of these procedures is to improve speech, jaw and dental function, aesthetics, and symptoms of sleep apnea. This is accomplished by surgical repositioning of the upper jaw (maxilla) and lower jaw (mandible). The most common procedures are lefort I osteotomies (upper jaw repositioning) and bilateral sagittal split osteotomies (lower jaw repositioning). At our institution, almost all cases include one or both of these two procedures. The majority of cases include bilateral sagittal split osteotomies (BSSO). As access to the jaws is through the oral cavity, these procedures are considered to be clean-contaminated surgeries due to the high intra-oral bacterial load. The result is that surgical site infections (SSIs) occur in 10-15% of cases. Studies show that the vast majority of these infections occur in the lower jaw (BSSO sites), presumably due to pooling of saliva and debris. SSIs are associated with patient discomfort, prolonged hospital stays, increased morbidity, and increased cost to healthcare systems.

The use of peri-operative antibiotics has been shown to significantly reduce the incidence of SSI following orthognathic surgery. There is currently no consensus on the dosing or specific antibiotic to be used. There is strong evidence that pre-operative antibiotics significantly decrease SSI compared to no antibiotics. However, to date, there is no good evidence to support the use of post-operative antibiotics to further decrease the rate of infection. Several studies have examined the use of post-operative antibiotics ranging between 1-7 days. The majority of studies were not able to demonstrate a statistically significant difference to justify the use of post-operative antibiotics. A systematic review by Danda and Ravi in 2011 suggested that there likely is a benefit to the use of post-operative antibiotics. Danda and colleagues in 2017 later conducted a trial comparing pre-operative antibiotics alone compared to pre-operative combined with post-operative antibiotics. A statistically significant difference was not found, however, they felt that this was due to a limited sample size. Overall, there is no robust data that supports the use of post-operative antibiotics. The World Health Organization guidelines currently recommend against the use of post-operative antibiotics in orthognathic surgery. However, they do comment that there is some weak evidence that suggests its use. It was deemed that this low quality evidence did not outweigh the potential harm of antimicrobial resistance, which results from inappropriate overuse of antibiotics. Antimicrobial resistance is a serious, growing problem which has deadly consequences.

Our current protocol at the QEII Health Sciences Center for peri-operative antibiotic administration is a single pre-operative dose of 2g cefazolin IV, followed by further doses every 8 hours post-operatively for a total of 24 hours (3 post-operative doses). Our study aims to investigate whether there is a need for these additional post-operative doses. If there is a benefit to these additional doses, the research team aims to investigate whether this benefit outweighs the risks. This question is of great importance in order to avoid an unnecessary contribution to antibiotic resistance and unnecessary potential adverse effects.

Participants will be assigned a study number and randomly allocated to one of two groups. Group A will receive a single pre-operative dose of 2g IV cefazolin. Group B will receive a pre-operative dose of 2g IV cefazolin, followed by an additional three doses post-operatively every 8 hours for a total of 24 hours.

Informed consent will be obtained at each participant's pre-operative assessment in the days leading up to the procedure. The participant will then select a group designation from a sufficiently mixed jar, and group A or B will be assigned to their study number.

For each patient, completed procedures will be documented, along with age, sex, smoking status, length of procedures, and complications. Complications including medication adverse reaction (allergy, toxicity, side effects), surgical complications, and any other significant complications related to the medications or deemed to be relevant to infection risk will be documented. Procedures will be carried out in the standard fashion. Patients will receive the same post-operative instructions and will be discharged with a chlorhexidine mouth rinse to be used for two weeks. Patients will return for follow-up at 2 weeks, 4 weeks, and 6 weeks post-operatively. Surgical site infection diagnosis will be made according to the CDC criteria and will be reported as either superficial, deep, or organ/space infections. Date of occurrence, location of infection, and treatment provided will be recorded on a standard form provided to surgeons.