Advanced mandibular osteoradionecrosis requires a segmental mandibulectomy with reconstruction using a free fibular flap. The conservation of labiomental sensation by lateralization of the inferior alveolar nerve is unusual during a segmental mandibulectomy. A protocol for the evaluation of labiomental sensation has been created for the clinical follow-up of operated patients. The patients included were patients with mandibular osteoradionecrosis who underwent a segmental mandibulectomy with reconstruction by free fibular flap and whose pre-operative labiomental sensation was preserved. All patients were followed-up by the same examiner and operated on by the same surgeon. The neuro-sensitive examination analyses the different forms of sensation at 1 week and at 12 months postoperatively. Between May 2017 and May 2018, 3 consecutive patients were assessed. The results of the labiomental sensitive evaluation using our evaluation protocol attest to the preservation of labiomental sensation. The operating time was increased by an average of 35 min per surgical procedure. The conservation and re-routing of the inferior alveolar nerve in segmental mandibulectomy with fibula free flap reconstruction in patients with osteoradionecrosis allows for the preservation of labiomental sensation, which improves the quality of life of patients. Our protocol can be used in all surgical procedure that affect sensibility.