Immediate inferior alveolar nerve reconstruction: Improving warfighter quality of life following mandibulectomy or traumatic avulsion of the mandible

Abstract

Background: Mandibular reconstruction has historically been challenging due to the complex, highly functional, and esthetic nature of the anatomy. The most common etiologies of these defects requiring resection include trauma, benign tumors, and malignant pathology. Mandibular defects have been treated with little consideration for neural reconstruction, leaving patient's orally incompetent with associated social stigma. Although recent advances in reconstructive techniques improve oral rehabilitation, immediate inferior alveolar nerve (IAN) reconstruction has not been widely adapted.

Objective: Here-in we seek to discuss the innovations of neural reconstruction of large segment mandibular defects and associated IAN defects and present an example case performed at Naval Medical Center San Diego (NMCSD).

Methods: Pertinent literature discussing maxillofacial reconstruction and nerve repair using autogenous nerve harvest and allograft was queried from available online resources.

Results: Six patients have received immediate reconstruction of the IAN using processed nerve allograft over the past three years. All obtained sensation to S3 within six months of surgery.

Conclusion: IAN repair using nerve allografts in conjunction with free flap reconstruction for large mandibular defects is a viable treatment and should be the new paradigm in maxillofacial reconstruction as it provides substantial quantifiable and qualitative improvements in social, functional, and esthetic outcomes of care.

Keywords: Fibula free flap; inferior alveolar nerve; jaw-in-a-day; maxillofacial reconstruction; nerve allograft.

Fig. 1

Clinical photo taken of the patient and the area of concern on presentation. The area is clinically significant for well-defined leukoplakia, class II mobility of #25 and 26, no purulent discharge, no tenderness to palpation, and gross calculus accumulation.

Fig. 2

(A) Panoramic radiograph reconstructed from initial cone beam CT scan revealing well-defined radiolucency between #25 and 26 with substantial bone loss. (B) Sagittal slice of initial cone beam CT scan at the site of #25–26 revealing complete bony erosion of the buccal and lingual plates. (C) 3-dimensional reconstruction of the cone beam CT scan further characterizing the bone loss in the area of concern with complete bony erosion. (D) Axial slice of initial cone beam CT scan demonstrating concerning bony changes, loss of cortication, and a moth-eaten appearance of the bone.

Fig. 3

(A) Clinical photograph taken of the patient 1 month post operatively from initial biopsy, extraction of #25 and 26, and incisional biopsy of cystic lesion associated with the lesion. (B) Post-resection specimen including soft tissue margins and extending posteriorly.

Fig. 4

(A and B) Intraoperative photographs taken of the fibula-free flap with the associated skin paddle with six dental implants in place as well as a pre-planned prosthetic placed out of occlusion per virtual surgical planning. Free flap is secured with a custom made titanium reconstruction bar and fixated to a 3-dimensional rendering of the patient’s post-resection model to demonstrate appropriate occlusion and contouring prior to inset.

Fig. 5

Clinical photo demonstrating skeletonization of native inferior alveolar nerve stump bilaterally and application of the nerve conduit and allographs prior to microvascular anastomosis.