Salvage surgery of vestibular schwannoma after failed radiotherapy: The Gruppo Otologico experience and review of the literature

Objectives: The use of radiation therapy has largely widespread and becomes in many centers the preference modality of treatment for symptomatic patients who are old, medically unfit for surgical therapy, those who refuse surgery and in some recurrent or residual growing tumors. The risk of radiotherapy failure in the treatment of vestibular schwannoma might be underestimated in the literature. The purpose of this study is to show the Gruppo Otologico experience with salvage surgery to better understand the surgical outcomes and difficulties in treating vestibular schwannoma after failed radiotherapy. Study design: Retrospective chart review of patients who required salvage surgery of vestibular schwannoma after failed radiotherapy. Settings: Quaternary referral otology and skull base center. Results: Between 1987 and 2010, 2500 cases of VS underwent surgical treatment at the Gruppo Otologico. Nineteen patients had received stereotactic radiation therapy before the surgical treatment. The interval time between radiotherapy and surgical salvage ranged from 1 to 10 years. In all the cases decision of surgery was taken following an increase in tumor size with or without new onset of symptoms. Complete tumor removal was achieved in 86.6% of the cases through a transotic, transcochlear or enlarged translabyrinthine approach with transapical extension. Difficult dissection of the tumor was encountered in 93.3% the cases. The facial nerve was anatomically preserved in 93.3% but its function was worsened in 73.3% of patients after at least 6 months of follow up. Malignant transformation of the vestibular schwannoma was encountered in one patient. Conclusion: Complete surgical resection of VS is more difficult after radiotherapy with relatively poor facial nerve outcomes and nearly impossible hearing preservation.