Vertically unstable fractured mandibular segment with attached genial tubercles as a parameter for difficulty during intubation for general anaesthesia-substantiation with computed tomographic (CT) scan evidence.

Abstract

To study and evaluate the anatomic alterations in the suprahyoid musculature, the hyoid bone, and the laryngeal inlet in patients with vertically unstable fractured mandibular segment with attached genial tubercles using computer tomography for substantiation of the clinical evidence and hypothesis of difficulty during intubation for general anaesthesia. Random sampling methodology was used to enrol patients with mandibular bilateral parasymphysis fracture qualifying for the classification of vertically unstable fractured mandibular segment with attached genial tubercles for group A patients. Patients with unilateral parasymphysis fracture with vertically stable mandibular segment were included in group B. Forty patients with parasymphysis fracture and no other associated facial fracture/injury were evaluated prospectively by comparing their pre-operative computer tomography (CT) images with post-operative CT images taken after the reduction of the fracture. Parameters evaluated were variation in the radiologic anatomy of the laryngeal inlet shape and alteration in the suprahyoid musculature after open reduction and internal fixation of the fracture when compared with pre-operative CT images. The following were the results/observations from this study among group A patients: (1) The distance between the genial tubercles and the hyoid was found to be reduced. (2) Dorsal bodily movement of the hyoid was observed suggesting loss of anterior hyoid support. (3) The posttraumatic changes in the shape of the laryngeal inlet were observed in cases with vertically unstable bilateral parasymphysis fracture. (4) Restoration of morphology of the laryngeal inlet and anterior-posterior distance between genium and hyoid after reduction. Computer tomographic findings confirm that the displacement of fractured mandible and resultant displacement of the genial musculature have their effect on the laryngeal morphology. These posttraumatic changes in cases with dorsally displaced vertically unstable fractured mandibular segment with attached genial tubercles should be considered as a vital parameter for assessing difficulty during intubation.