Association between facial nerve second genu angle and facial canal dehiscence in patients with cholesteatoma: evaluation with temporal multidetector computed tomography and surgical findings / Associação entre o ângulo do segundo joelho do nervo facial e deiscência do canal facial em pacientes com colesteatoma: avaliac¸ão do osso temporal por tomografia com multidetectores e pelos achados cirúrgicos

Abstract Introduction: Otitis media, mastoiditis or the pressure effect of tumorous lesions such as cholesteatoma can be the cause of facial canal dehiscence and facial nerve paralysis. The most common segment involved in dehiscence is the tympanic segment and the second most common is the lateral aspect of the facial canal in the oval window area. Objective: To determine the prevalence of the facial canal dehiscence and the relationship between the angle at the second genu of the facial nerve and facial canal dehiscence. Methods: We evaluated the surgical findings in 113 patients who underwent surgery for cholesteatoma. Facial canal dehiscence was detected in 62 of the 113 patients. Patients were divided into two groups: Group 1, with dehiscence of the facial canal and Group 2, without dehiscence of the facial canal. Results: The mean angles at the second genu of the facial nerve in Groups 1 and 2 were 117.8º ± 9.63º and 114º ± 9.9º, respectively. There was a statistically significant difference between the mean angles at the second genu for the two groups (p = 0.04). Conclusion: In patients with dehiscence of the facial canal, the angle at the second genu was found to be wider than those without dehiscence.

Resumo Introdução: Otite média, mastoidite ou a compressão por lesões tumorais como o colesteatoma podem ser a causa da deiscência do canal facial e paralisia do nervo facial. A deiscência ocorre mais frequentemente no segmento timpânico, seguido do aspecto lateral do canal facial na área da janela oval. Objetivo: Determinar a prevalência da deiscência do canal facial e sua relação com o ângulo no segundo joelho do nervo facial. Método: Avaliamos os achados cirúrgicos para detecção de deiscência do canal facial em 113 pacientes submetidos à cirurgia de colesteatoma. A deiscência do canal facial foi observada em 62. Os pacientes foram divididos em dois grupos: Grupo 1, com deiscência do canal facial, e Grupo 2, sem deiscência do canal facial. Resultados: Os ângulos médios no segundo joelho do nervo facial nos grupos 1 e 2 foram 117,8º ± 9,63º e 114º ± 9,9º, respectivamente. Houve diferença estatisticamente significante entre os ângulos médios no segundo joelho para os dois grupos (p = 0,04). Conclusão: Em pacientes com deiscência no canal facial, foi observado que o ângulo do segundo joelho era maior do que naqueles sem deiscência.

Association between facial nerve second genu angle and facial canal dehiscence in patients with cholesteatoma: evaluation with temporal multidetector computed tomography and surgical findings.

INTRODUCTION: Otitis media, mastoiditis or the pressure effect of tumorous lesions such as cholesteatoma can be the cause of facial canal dehiscence and facial nerve paralysis. The most common segment involved in dehiscence is the tympanic segment and the second most common is the lateral aspect of the facial canal in the oval window area. OBJECTIVE: To determine the prevalence of the facial canal dehiscence and the relationship between the angle at the second genu of the facial nerve and facial canal dehiscence. METHODS: We evaluated the surgical findings in 113 patients who underwent surgery for cholesteatoma. Facial canal dehiscence was detected in 62 of the 113 patients. Patients were divided into two groups: Group 1, with dehiscence of the facial canal and Group 2, without dehiscence of the facial canal. RESULTS: The mean angles at the second genu of the facial nerve in Groups 1 and 2 were 117.8°±9.63° and 114°±9.9°, respectively. There was a statistically significant difference between the mean angles at the second genu for the two groups (p=0.04). CONCLUSION: In patients with dehiscence of the facial canal, the angle at the second genu was found to be wider than those without dehiscence.