A Cadaveric Study of the Position and Tracking of the Inferior Alveolar Nerve and Lingual Nerve: Relevancy with Sagittal Split Ramus Osteotomy

Introduction:The inferior alveolar nerve (IAN) and lingual nerve (LN) are at great risk of injury during sagittal split ramus osteotomy (SSRO) and damage to both nerves could have a negative impact on a patient's quality of life. This study aimed to describe the precise location of the IAN and LN in all dimensions of the mandible and to create a safe surgical margin for SSRO that is directly applicable in the clinical setting. Materials and Methods:Twenty freshly frozen cadavers with 40 hemimandibles were used in this study. The mandible was marked as ramus, angle, and body segments. After splitting was performed, measurements of the three segments were taken. Results:The mean distance between the IAN and lingual margin was 3.3, 3.6, and 4.3 mm for the ramus, angle and body, respectively. The IAN was located near the inferior border of the mandible, at the level of the ramus. The IAN then became more central in angle and was situated closer to the inferior border of the mandible once again at the level of the body and the vertical osteotomy should not be placed deeper than 10 mm. The LN lies posteroinferior to the internal oblique ridge and anterior to the IAN. At the level of the mandibular canal opening, the LN was located approximately 1 cm in front of the lingula. Conclusion:Our study can be used as a guide for determining the depth of vertical and horizontal osteotomies and help minimize IAN and LN injuries during SSRO.