Clinical and anatomical aspects of possible mylohyoid nerve injury during genioplasties

Abstract

Damage to the cutaneous branch of the mylohyoid nerve (CBMN) during genioplasties is possible but rare. The aim of this cadaveric study was to demonstrate possible mechanisms of injuring the CBMN during genioplasties. Mandibulotomy access was used to carry out sublingual and lateral cervical dissections on 10 formalinized cadavers with a mean age of 65 years. The length of the mylohyoid nerve was measured at three sections on the mandible. The posterior section of the mylohyoid nerve was 8.7 +/- 0.5 mm; the middle section was 14.5 +/- 0.9 mm and the anterior section was 15.6 +/- 1.2 mm in length. The submental skin island of 7 specimens had unilateral innervation by the CBMN. The bilateral innervation pattern was detected in 3 of the specimens. Damage to the sensory and the motor branches of the mylohyoid nerve can occur during genioplasties by transaction of the soft tissue pedicle attached to the mental spine and inferior border of the symphis. Surgeons should pay attention during dissection and osteotomy of the chin to avoid complications of the mylohyoid nerve and its branches.