Injury to Anatomic Structures Due to Fixation Device in Management of Mandibular Fracture

ORIF is the gold standard for the management of mandibular fractures. The chances of postoperative complications are due to infection, damage of the inferior alveolar nerve canal, or tooth root during the fixation of the fracture fragments. Fixation hardware placed in the vicinity of the vital structures may encroach on the anatomic structures, leading to postoperative complications.

The aim of this study is to evaluate the injury to the anatomic structures in the proximity of the fracture line due to the fixation device.

This retrospective study was conducted in a tertiary care teaching hospital from July 2021 to June 2023. The cases of maxillofacial trauma reported and referred from peripheral centers were considered duly, applying the inclusion and exclusion criteria. Patients having mandibular fractures from one mandibular foramen to another with or without associated other facial fractures were treated by ORIF under general anesthesia. The patient was followed up at 1 week, 1 month, 3 months, and 6 months. The cases of postoperative complications were further investigated by CBCT.

There were 67 patients (56 males and 11 females) with 86 fracture lines in the age group of 18-55 years with an average age of 35.2 years. Postoperatively 7 patients presented with unilateral paresthesia of the lower lip and chin region. CBCT revealed that the mean distance of the screw from the inferior alveolar nerve canal was 3.02 mm. None of these cases had injury to the nerve canal or roots of teeth. All the patients recovered from paresthesia within 6 months.

Complications like injury to the inferior alveolar nerve (IAN) with sensory disturbances to the lower lip and chin, as well as tooth/tooth root fractures, may occur due to mandibular fracture, surgical manipulation, and fixation devices. The anatomic structures in the vicinity of the fracture line can be damaged during the fixation of the fracture fragments by the bone plates and screws. In the present study, it was found that 7 out of 67 patients presented with unilateral paresthesia of the lower lip and chin. CBCT analysis showed a considerable distance of 3.02 mm from the inferior alveolar nerve canal to the screws. There was no evidence of hardware encroachment on the IAN or tooth roots.

Selection and placement of appropriate fixation devices, particularly the length of the bone screws, are crucial to avoid injury to the anatomic structures.