Antibiotics for Mandible Fractures?

Clinical Scenario:

You’re working a busy Saturday overnight, and the traumas are rolling in. You’ve just finished packaging up your patient with an abdominal GSW for the OR, and they’re bringing back a new patient before the stretcher is even flipped over. He’s a 25 year-old male, presenting to the ED after being in an altercation with some friends of friends. He was hit in the face during the fistfight. He is complaining of left-sided jaw pain and facial swelling. He is able to open his jaw to a reasonable degree, but uncomfortably. There is no apparent intra-oral injury. CT max/face shows multiple minimally-displaced fractures of the left mandibular ramus and paramental region.

Luckily for you the ENT consult resident is still in the department from seeing your last patient with a complicated ear lac. She evaluates the patient with her senior and looks over the images. The patient will need surgical repair, but is OK for discharge with close pre-op follow-up next week. They recommend mouthwash, nasal spray, analgesia, and antibiotics.

Clinical question:

When are prophylactic antibiotics indicated in mandibular fractures, and how effective are they are preventing infection?

3D CT recon of minimally-displaced mandible fractures. Image from MD Consult.

Literature review:

The use of antibiotics for mandible fractures has been common practice for some time, based on the assumption that such fractures are at high risk of infection due to contamination with oral flora. However, like many dogmatic practices, it appears the initial evidence upon which the “standard practice” is based is sorely lacking [1]. 

A recent systematic review of 31 studies including a total of 5,437 patients published in the Journal of Oral and Maxillofacial Surgery in 2011 found that the overall evidence to support the use of prophylactic antibiotics in mandible fractures is of poor quality [1]. Only 9 of the included studies were RCTs, including 974 patients. The study author laments numerous methodological shortcomings of these RCTs – all had relatively small cohort sizes, none included power calculations, 7/9 RCTs did not describe randomization method, none reported allocation concealment, only one study reported an intention-to-treat analysis, and none reported NNT figures. 

The author found it impossible to perform any quantitative analysis due to heterogeny of study design and poor quality of included studies. For example: only 10/31 studies included information on time from injury to operative management, 13/31 studies did not describe the type of antibiotic used, half of studies did not describe route of administration of duration of course, and 23/31 studies did not report dose of antibiotic used! Significant heterogeny was also found between the types of fractures included, the types of surgical repairs performed, and the types of antibiotic used.

Five of the 9 included RCTs concluded that antibiotics were effective in preventing infection. However, the rates of infections varied widely between included studies – from 4.5-62% in untreated groups and 1.9-29% in treated groups, limiting applicability of those conclusions.

The study author reports that there may be some signal indicating antibiotics are superior to nothing in terms of preventing infection, but concludes:

“Even then, we are not sure which antibiotic to use, we do not know best route of administration, we are not confident about duration of course, and we have very limited information about the optimal dosage. Even worse, we do not have the slightest idea about how many patients we need to treat with prophylactic antibiotics to prevent a complication, and there is no clue about how much this costs the health care spectrum. Therefore, even in this very optimistic scenario, the available evidence is not sufficient to support a standard protocol for the use of prophylactic antibiotics in the treatment of mandible fracture.”

Recommendations for post-operative antibiotics have also become more conservative in recent years. A study group in Switzerland conducted an RCT comparing 24hrs of post-op IV antibiotics only vs post-op IV antibiotics followed by a 5-day PO antibiotic course [2]. It was designed as a pilot study and only included 59 patients, but they found no significant differences in incidence of infection between the two groups.

Another recent retrospective review of 197 patients who underwent operative repair of mandible fracture, published by a group at St. Louis University, found that advanced patient age was the only statistically significant difference in infected and uninfected groups [3]. Injury severity score, fracture type, duration of antibiotic course, and antibiotic type did not differ significantly between the two groups. One primary limitation of this study is the low rate of the primary outcome (only 9 post-op infections occurred).

Take-home:

- There is insufficient evidence to strongly support or discourage the routine use of prophylactic antibiotics in closed mandible fractures.

- Signal from some studies indicating possible benefit of antibiotics warrants further investigation in the form of a well-designed, adequately-powered, placebo-controlled RCT.

References:

1) Kyzas PA. Use of antibiotics in the treatment of mandible fractures: a systematic review. Journal of Oral and Maxillofacial Surgery 2011;69(4):827-32.

2) Schaller B, Soong PL, Zix J, Iizuka T, Lieger O. The role of postoperative prophylactic antibiotics in the treatment of facial fractures: a randomized, double-blind, placebo-controlled pilot clinical study. Part 2: mandibular fractures in 59 patients. Br J Oral Maxillofac Surg 2013;51:803-7.

3) Hindawi YH, Oakley GM, Kinsella CR, Cray JJ, Lindsay K, Scifres AM. Antibiotic duration and postoperative infection rates in mandibular fractures. Journal of Craniofacial Surgery 2011;22(4):1375-7.

Submitted by Aurora Lybeck, PGY-3.
Edited by C. Sam Smith, PGY-3.

Faculty reviewed by Chris Brooks.