Preserving the marginal mandibular branch of the facial nerve during submandibular region surgery: a cadaveric safety study

BACKGROUND: The marginal mandibular branch of the facial nerve is vulnerable to iatrogenic injuries during surgeries involving the submandibular region. This leads to significant post-operative morbidity. Studies assessing accurate anatomical landmarks of the marginal mandibular branch are sparse in South Asian countries. Present study was conducted to assess the relationship between the marginal mandibular branch and the inferior border of the body of mandible. METHODS: Twenty-two preserved cadavers of Sri Lankan nationality were selected. Cadavers were positioned dorsal decubitus with necks in extension. The maximum perpendicular distance between the inferior/caudal most ramus of the marginal mandibular branch and the inferior border of the body of the mandible was recorded on both hemi faces. RESULTS: Recorded maximum distance was 17.65 mm on left side and 10.80 mm on right side. Mean maximum distance, was 7.12 ± 2.97 mm. There was no statistically significant difference in the maximum deviation on left (7.84 ± 3.41 mm) and right sides (6.44 ± 2.37 mm). CONCLUSION: Course of the marginal mandibular nerve is complex. If the distance of the incision in the posterior submandibular approach is less than 2 cm from the inferior border of the mandible, there is a high probability of damaging the inferior ramus of the marginal mandibular branch of the facial nerve.