RESUMO
O conhecimento detalhado da anatomia do nervo facial e de seus ramos, em especial o ramo marginal mandibular, é de fundamental relevância em cirurgias para tratamento de fraturas mandibulares com uso do acesso cirúrgico Risdon, evitando-se possíveis lesões. O objetivo deste trabalho é o de avaliar a função do ramo marginal mandibular após tratamento cirúrgico dessas fraturas, utilizando-se o acesso tipo Risdon. Foi avaliada a função do nervo marginal mandibular de 44 pacientes com fraturas de corpo e ângulo mandibulares, utilizando exame visual com base na escala de classificação do nervo facial House-Brackmann, no pré-operatório e pós-operatório (24h). Os pacientes que apresentaram algum grau de disfunção em 24 h foram reavaliados em 01 semana, 01 mês e 03 meses de pós-operatório. Do total avaliado, treze (29,55%) apresentaram algum grau de disfunção no 1º DPO, e trinta e um pacientes (70,45%) apresentaram normalidade na função, sendo o gênero feminino mais acometido (71,43%). Após 03 meses, 91% dos pacientes apresentaram grau I (normal) e 9%, grau II (disfunção branda). Assim, pode-se concluir que a maioria dos pacientes avaliados apresentou normalidade na função do nervo marginal mandibular em todos os tempos pós-operatórios, sendo a disfunção branda a mais encontrada, demonstrando segurança nos acessos Risdon realizados.
Detailed knowledge of the anatomy of the facial nerve and its branches, especially the marginal mandibular one is of fundamental importance in surgical treatment of mandibular fractures by making use of the Risdon surgical approach. The aim of this study is to evaluate the function of the marginal mandibular branch of facial nerve after surgical treatment these fractures by access Risdon. 44 patients with fractures of the mandibular body and angle, and the marginal mandibular nerve function being analyzed through visual inspection based on the rating scale in House-Brackmann facial nerve, in the preoperative and postoperatively (24 hours). Patients who had some degree of dysfunction within 24 hours were reassessed during 01 week, 01 month and 03 months postoperatively. Thirteen (29.55%) had some degree of dysfunction in a PO and thirty one (70.45%) patients had normal function, being females the most affected ones (71.43%). After 03 months, 91% of patients had grade I (normal) and 9% had grade II (mild dysfunction). It can be concluded that the majority of patients showed normal function of the marginal mandibular nerve at all times postoperatively demonstrating safety in the Risdon approaches performed.
RESUMO
Background: Surgery of face and parotid gland may cause injury to branches of the facial nerve, which results in paralysis of muscles of facial expression. Knowledge of branching patterns of the facial nerve and reliable landmarks of the surrounding structures are essential to avoid this complication. Objective: Determine the facial nerve branching patterns, the course of the marginal mandibular branch (MMB), and the extraparotid ramification in relation to the lateral palpebral line (LPL). Materials and methods: One hundred cadaveric half-heads were dissected for determining the facial nerve branching patterns according to the presence of anastomosis between branches. The course of the MMB was followed until it entered the depressor anguli oris in 49 specimens. The vertical distance from the mandibular angle to this branch was measured. The horizontal distance from the LPL to the otobasion superious (LPL-OBS) and the apex of the parotid gland (LPL-AP) were measured in 52 specimens. Results: The branching patterns of the facial nerve were categorized into six types. The least common (1%) was type I (absent of anastomosis), while type V, the complex pattern was the most common (29%). Symmetrical branching pattern occurred in 30% of cases. The MMB was coursing below the lower border of the mandible in 57% of cases. The mean vertical distance was 0.91±0.22 cm. The mean horizontal distances of LPL-OBS and LPLAP were 7.24±0.6 cm and 3.95±0.96 cm, respectively. The LPL-AP length was 54.5±11.4% of LPL-OBS. Conclusion: More complex branching pattern of the facial nerve was found in this population and symmetrical branching pattern occurred less of ten. The MMB coursed below the lower border of the angle of mandible with a mean vertical distance of one centimeter. The extraparotid ramification of the facial nerve was located in the area between the apex of the parotid gland and the LPL.