Long-term facial nerve clinical evaluation following vestibular schwannoma surgery

Abstract

-Background: Facial function is important in accompaniment of patients operated on vestibular schwannoma (VS). Objetive: To evaluate long term facial nerve function in patients undergoing VS resection and to correlate tumor size and facial function in a long-term follow-up. Method: Transversal study of 20 patients with VS operated by the retrosigmoid approach. House-Brackmann Scale was used preoperatively, immediately after surgery and in a long-term follow-up. Student t test was applied for statistic analysis. Results: In the immediate postoperative evaluation, 65% of patients presented FP of different grades. Improvement of facial nerve function (at least of one grade) occurred in 53% in the long-term follow-up. There was statistically significant difference in facial nerve outcome in long-term follow-up when tumor size was considered (p<0.05). Conclusion: The majority of patients had improvement of FP in a long-term follow-up and tumor size was detected to be a factor associated with the postoperative prognostic.Key wordS: vestibular schwannoma, facial nerve function, retrosigmoid approach. Avaliação clínica tardia do nervo facial no pós-operatório de schwannoma vestibularResumo -Contexto: A função facial é importante para acompanhamento dos pacientes operados de schwannoma vestibular (SV). Objetivo: Avaliar o grau de paralisia facial (PF) em pacientes operados de SV, correlacionando tamanho do tumor com função facial na avaliação tardia. Método: estudo transversal com análise seriada de 20 pacientes com SV operados pela via retrosigmóide-transmeatal. A escala de House-Brackmann foi utilizada no pré-operatório, pós-operatório imediato e pós-operatório tardio. o teste t de Student foi aplicado para análise estatística. Resultados: No pós-operatório imediato, 65% dos pacientes apresentaram graus variados de PF, sendo que 53% destes obtiveram melhora de pelo menos um grau de House-Brackmann na avaliação tardia. Houve diferença significativa no resultado da função facial no pós-operatório tardio quando o tamanho do tumor foi considerado (p<0.05). Conclusão: A maioria dos pacientes da amostra apresentou melhora da PF no pós-operatório tardio, sendo o tamanho do tumor um fator associado ao prognóstico.PAlAVrAS-cHAVe: schwannoma vestibular, função facial, via retrosigmóide.

Factors associated with preservation of facial nerve function after surgical resection of vestibular schwannoma

“…The facial nerve can usually tolerate a large degree of stretching, compression or distortion without apparent facial palsy [19, 24]. However, as the tumor grows, the nerve comes under even greater tension, which increases the likelihood of stretch injury, and this may explain the high rate of facial palsy seen in patients with large tumors [19, 24].…”

“…Even though advances in surgical techniques have improved facial nerve outcomes, functional preservation is still an issue because injury to the facial nerve has significant physical and psychological consequences for the patient [14–16]. It has been suggested that age, tumor size, and surgical approach all can impact ultimate facial functional outcome [16–19]. …”

Post-operative complications after removal of sporadic vestibular schwannoma via retrosigmoid-suboccipital approach: current diagnosis and management

“…Nonetheless, according to other authors [20] the risk of facial palsy after vestibular schwannoma surgery is the lowest among all available surgical approaches when using the translabyrinthine approach. In order to assess the facial nerve function, pre-as well as post-operatively, the most commonly used tool was the House-Brackmann scale [4,7,8,13,16,17,21]. Facial electromyography (EMG) has also been a useful tool, because it facilitates the surgical procedure and plays an important role in the prevention of facial paresis.…”

“…A clinical trial involving facial nerve functionality preservation [21] tested the efficacy of one dose of corticosteroids (usually dexamethasone) intraoperatively. The theory was based on the fact that facial nerve malfunction can be a result of neural edema and that patients might benefit from corticosteroid use, as in idiopathic facial palsy.…”

Neuroanatomical correlation of the House-Brackmann grading system in the microsurgical treatment of vestibular schwannoma

“…Prognostic factors such as age, tumor size, extent of resection, and surgical approach have been implicated for predicting facial nerve function outcome after surgical removal of VS. 20,55,59,102 In a meta-analysis of 296 studies involving more than 25,000 patients that included outcome data for facial nerve function of surgically treated VS patients, Sughrue et al 86 found that tumor size of less than 20 mm, the use of the middle fossa approach, and the use of neuromonitoring during surgery were associated with facial nerve preservation. However, others have found through retrospective review of patients presenting at single institutions that for small tumors, specifically those smaller than 20 mm, the preservation of facial G-I).…”