Risk factors for postoperative facial nerve injury in retromandibular-approach surgery: A retrospective study including CT measurements of maxillofacial bone structure.

The purpose of this retrospective study was to identify risks of postoperative facial nerve injury (FNI) in mandibular condylar fractures. A total of 59 consecutive cases of condyle fracture or plate removal with a retromandibular transparotid approach (RMTA) were divided into FNI and non-FNI groups that were evaluated for associations with age, sex, laterality, fracture type, height, weight, body mass index (BMI), and maxillofacial bone height and width diameters on computed tomography (CT). FNI occurred in 11 of 59 patients (18.64%), all of them female (p = 0.0011). Other statistically significant factors on univariate analysis for FNI included a short height (156.95 ± 8.16 cm vs. 164.29 ± 9.89 cm, p = 0.04), low weight (46.08 ± 8.03 kg vs. 58.94 ± 11.79 kg, p = 0.003), low BMI (18.64 ± 2.63 kg/m2 21.68 ± 3.02 kg/m2, p = 0.007), short condylion-anterior fracture distance (19.34 ± 3.15 mm vs. 22.26 ± 3.96 mm, p = 0.04) and short condylion-posterior fracture distance (20.12 ± 3.98 mm vs. 25.45 ± 5.02 mm, p = 0.009). Our retrospective study suggested that FNI with RMTA surgery occurs particularly in female patients and may occur more frequently in patients who are short, lean or have high condyle fractures.