[Evaluation of sensory deficit of the inferior alveolar nerve after mandibular osteotomy].
INTRODUCTION: Injury of the inferior alveolar nerve (IAN) is one of the most common complications of mandibular osteotomy. The wide differences in results published to date led us to evaluate the incidence of sensorial disorders persisting for one year in a series of 40 patients. MATERIAL AND METHOD: This study included 40 patients aged 14-58 years. We studied subjective expression of sensorial disorders using a questionnaire with items for the different orofacial functions related to the IAN. We studied the clinical expression of these sensorial disorders by testing the three modes of exteroceptive sensitivity (tact, temperature, pain) in 25 patients. Four clinical tests appropriate for the area of the mental nerve. Somesthesic evoked potentials were recorded in 8 patients. RESULTS: 77% of the patients complained of altered skin sensitivity but a sensorial deficit was revealed by clinical tests in only 60%. Somesthesic evoked potentials were perturbed for 64% of the nerves with a clinical deficit and in 100% without a clinical deficit. DISCUSSION: There was a greater incidence of subjective complaints than objective nerve injury. Recoring somesthesic evoked potentials provides interesting information for the electrophysiological diagnosis of nerve injury. Indications could be widened for traumatic injury of the IAN, particularly to obtain medicolegal documentation.