Outcomes of Immediate Allograft Reconstruction of Long-Span Defects of the Inferior Alveolar Nerve

Abstract

Contemporary management of ablative jaw defects includes not only hard and soft tissue reconstruction, but also restoration of neurosensory function. The goal of this study was to determine the outcomes of immediate reconstruction of long-span defects (≥50mm) of the inferior alveolar nerve (IAN) after ablative mandibular resection using allogeneic nerve grafts. A retrospective cohort study of patients who underwent immediate reconstruction of IAN gaps of at least 50mm with allogeneic nerve graft (AxoGen Avance, Alachua, FL) at a single academic medical center by a single surgeon (M.M.) from September 2013 to March 2015 was completed. Demographic and clinical data were collected for each patient and analyzed using clinical neurosensory testing and were reported using the Medical Research Council Scale (MRCS) for functional sensory recovery. In addition, patient subjective perception of neurosensory recovery was recorded using a visual analog scale (VAS). Subjective (VAS) and objective (MRCS) measurements of functional sensory recovery were recorded and compared across the study population. In addition, examined demographic and clinical data included patient age, gender, pathology, length of nerve allograft, and follow-up period. Of 12 with nerve repairs, 7 patients met the inclusion criteria. The average age was 34.7years (range, 18 to 61yr) and 71.4% were men. All IAN defects resulted from resection of mandibular pathology (6 benign lesions, 1 malignant lesion). Six of the 7 IAN defects were reconstructed with a 70-mm nerve allograft, and 1 nerve defect was reconstructed with a 50-mm graft. Mean follow-up time was 17.7months (range, 10 to 27.5months). Mean VAS score reported was 3.7 (range, 0 to 7). In addition, 85.7% of patients displayed return of some superficial pain and tactile sensation without over-response (S3), with 14.3% displaying good stimulation localization (S3+). The patient who displayed S3+ recovery underwent reconstruction with the 50-mm graft. Only 1 of the 7 patients had no neurosensory recovery (S0). Immediate reconstruction of the IAN with allogeneic nerve grafting of long-span defects (≥5cm) is a viable and predictable option to achieve useful functional sensory recovery.