Evaluation of Mandibular Fractures in a Tertiary Military Hospital: A 10-year Retrospective Study

Abstract

Objective: The study aimed to evaluate mandibular fractures in a tertiary military hospital, to determine the age group in which injury occurred most often, to examine the various mechanisms of injury, to determine the anatomical part of the mandible most frequently affected and to determine if there were significant relationships between the various mechanisms of injury and the different fracture sites.

Methods:

Design: Cross-sectional retrospective study

Setting: Tertiary Public Military Hospital

Patients: Medical records of 328 active military personnel and their dependents, treated for mandibular fracture at the Department of Otorhinolaryngology – Head and Neck Surgery, Armed Forces of the Philippines Medical Center from January 1999 – December 2009 were retrospectively reviewed for data regarding sex, age, various mechanisms of injury and fractured anatomical part of the mandible. The number of fractures per site according to mechanism of injury was tabulated and prevalence ratios (95% confidence intervals) and p values were computed for the different fracture sites among the various mechanisms of injury. The probability or risk of sustaining fractures in these sites based on mechanism of injury was then computed.

Results: The most fractured anatomical part of the mandible was the body (28%), followed by the parasymphysis (24%), angle (17%), symphysis (12%), ramus (8%), condyle (7%), alveolar ridge (3%) and coronoid (1%). There were associated injuries in 54% of those with mandibular fractures. In these patients, zygomaticomaxillary complex fractures occurred in 25%, head and neck abrasions and lacerations in 30%, head injuries in 28%, ocular injuries in 10%, nasal fractures in 8% and cervical spine fractures in 5%. Other injuries present were extremity trauma in 60%, thoracic trauma in 5% and abdominal trauma in 3%. Males dominated with a ratio of 99:1. Males 21 to 30 years of age sustained the most mandible fractures. Most fractures were caused by vehicular accidents (60%), followed by gunshot wounds (31%), falls (4%), violent assault (4%) and sports activities (1%). Alcohol was a contributing factor at the time of injury in 20.6% of fractures. All cases were treated by open reduction and internal fixation with plating or wiring.

Conclusion: The body was the most commonly fractured anatomic region of the mandible in this series. There appeared to be a statistically significant relationship between violent assault and fractures of the ramus, but not between the other mechanisms of injury and the site of fracture. Its prevalence ratio of 3.32 (95% confidence interval: 1.13; 9.74, p value 0.039) suggests that the prevalence of fractures of the ramus among those exposed to violent assault was 3 times higher than those who were not.

Keywords: mandibular fractures, etiology, maxillofacial injuries, trauma