Inferior alveolar nerve impairment after mandibular sagittal split osteotomy: an analysis of spontaneous recovery patterns observed in 60 patients.

Sensory impairment after bilateral sagittal split osteotomy (BSSO) due to inferior alveolar nerve (IAN) lesions may be either temporary or permanent and either complete or partial. The aim of this prospective study is to evaluate, by means of objective sensory testing, IAN sensory disturbances development in patients who underwent BSSO.IAN sensory disturbances development at the first week, fourth week, sixth month, and twelfth month of follow-up review in a group of 60 patients who underwent BSSO from January 1, 1998, to July 31, 1999, at the Maxillofacial Surgery Department of the "La Sapienza" University of Rome. The 60 patients were examined in the presurgical period; the IAN functionality regarding thermal sensibility, nociception, and two-point discrimination, was assessed at follow-up in 120 sides. In our study the highest rate of spontaneous recovery of the entire IAN functionality was observed at the sixth month. This finding witnesses how neuropraxia and axonotmesis give a spontaneous recovery that most frequently occurs within 6 months from surgery, independently from age and sex of the patient. The persistence of anesthesia over 12 months could be a sign of neurotmesis.