The Anatomic Landmark Approach to Extratemporal Facial Nerve Repair in Facial Trauma.

An Q Lam,Duong Tran Van,Thuy Tran Phan Chung,Hung Do Quang,Albert J Fox,Luan Tran Viet

doi:10.7759/cureus.22787

Abstract

ObjectiveIn this study, we aimed to examine the topical anatomic landmarks of the facial nerve (facial nerve areas) and their application in cases of extratemporal facial nerve injury in maxillofacial trauma.Materials and methodsWe analyzed 25 maxillofacial trauma patients with facial paralysis who underwent facial nerve reanimation surgery at the Ho Chi Minh City National Hospital of Odonto-Stomatology. The characteristics of each trauma case, including the mechanism of injury, the length of the facial injury, and the location/position of injury, were recorded. The association of the injured nerves with the trauma characteristics and the external landmarks of the facial danger zones was analyzed.ResultsThe buccal branches had the highest rate of paralysis (22/25 cases), followed by zygomatic branches (15/25), frontal branches (11/25), marginal branches (6/25), and the main trunk (1/25). There were four areas related to the external facial nerve landmarks (facial nerve areas) that helped us find the affected nerves: wounds in Area 1 resulted in frontal branch paralysis in five out of eight cases (62.5%); wounds in Area 2 resulted in zygomatic branch paralysis in 8/13 cases (61.5%) and buccal branch paralysis in 12/12 cases (100%); wounds in Area 3 resulted in marginal branch paralysis in 5/10 cases (50%); and wounds in Area 4 alone resulted in main trunk paralysis in one out of four cases or at least two main branches in three out of four cases.ConclusionExtratemporal facial paralysis after facial trauma can be complex and highly variable, leading to difficulty in finding and repairing facial nerves. Thorough clinical examination and evaluation of trauma characteristics can aid in the identification of facial paralysis and repair. Mapping facial wounds using the four anatomic surface landmarks (Areas 1-4 as outlined in this research) helped us anticipate which branches might be traumatized and estimate the position of the distal and proximal endings to repair the nerves in all cases.

Highlights

IntroductionInjuries caused by traffic and labor accidents and assault are a significant concern
The buccal branches had the highest rate of paralysis (22/25 cases), followed by zygomatic branches (15/25), frontal branches (11/25), marginal branches (6/25), and the main trunk (1/25)
There were four areas related to the external facial nerve landmarks that helped us find the affected nerves: wounds in Area 1 resulted in frontal branch paralysis in five out of eight cases (62.5%); wounds in Area 2 resulted in zygomatic branch paralysis in 8/13 cases (61.5%) and buccal branch paralysis in 12/12 cases (100%); wounds in Area 3 resulted in marginal branch paralysis in 5/10 cases (50%); and wounds in Area 4 alone resulted in main trunk paralysis in one out of four cases or at least two main branches in three out of four cases

Summary

Introduction

Injuries caused by traffic and labor accidents and assault are a significant concern. Maxillofacial trauma accounts for 16% of major trauma injuries [1]. Maxillofacial trauma includes injuries to the soft tissue, facial bone fractures, and facial paralysis. Patients with facial paralysis can suffer from severe sequela resulting in cosmetic issues as well as affecting functional aspects of daily lives and social communication [2]. Microsurgical techniques have enabled surgeons to re-anastomose the facial nerve. In posttraumatic cases, the surgeon needs to find the proximal and distal end of each injured branch to perform end-to-end re-anastomosis or use a nerve graft to maximize the surgical outcome [1]. In traumatic cases, the anatomy of the structures can be altered due to soft tissue damage, bone fractures, and scar contracture. Exploring the injured facial nerve, and identifying the proximal and distal

Methods

Results

Discussion

Conclusion