Operator Experience and Fracture Location Affects the Rate of Facial Nerve Injury in Condylar Fractures: An Analysis of 89 Cases.

PURPOSE

The purpose of this study was to measure the frequency and identify risk factors for facial nerve injury (FNI) in the open treatment of condylar neck and subcondylar fractures.

MATERIALS AND METHODS

A prospective cohort study was conducted over 5 years on patients who were treated surgically for mandibular condylar fractures using the retomandibular transparotid approach (RMTA). The primary result was FNI occurrence (yes/no). The predictor variables were demographic, fracture location, and pattern (dislocation, present or not), as well as surgeon experience. Post-treatment functional facial nerve changes were initially assessed in the operating room as the patient regained consciousness and documented thereafter within, the 1st and 3rd weeks, and 3rd and 6th months. Appropriate statistics were computed and, SPSS version 16 was used to analyze the data. χ test and Fisher exact test were used to assess significance (P ≤ 0.05).

RESULTS

Eighty-nine patients with 102 condylar fractures (63 subcondylar and 26 condylar neck), with a mean age of 28.5±7.5 years and 91% men were evaluated. There were 15 subjects (16.8%) with FNI and among them 6 subjects had persistent facial weakness for 6-8 weeks that completely resolved within 3 months, with no permanent facial nerve paralysis. The marginal mandibular (n = 7), buccal (n = 6), and zygomatic (n = 2) were the facial nerve branches involved. Risk factors for FNI were operator' inexperience, fracture-dislocation, and condylar neck fracture to the site and location of the fracture. Multivariate logistic regression showed that the location of the fracture at neck level (0.030∗), fracture dislocation (<0.001∗), and operator's inexperience (0.003∗) were significant risk factors for postoperative facial nerve injury (P ≤ 0.05).

CONCLUSIONS

If conducted properly, the RMTA is a safe method for treating condylar fractures with rare major complications; however, fracture dislocation, fractured condylar neck, and operator' in-experience were significantly associated with increased risk of developing transient postoperative FNI.