Article
Strategy for hearing conservation in a series of 600 vestibular schwannomas
Strategien zur Hörerhaltung bei einer Serie von 600 Vestibularisschwannomen
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Published: | May 8, 2019 |
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Objective: Preservation of auditory function is a major goal on the patient’s and on the surgeon’s side in vestibular schwannoma treatment. This analysis was to identify which surgical strategy offers a realistic chance in this respect.
Methods: In a consecutive series of 600 VS surgeries, patients with residual pre-operative hearing were analyzed for their individual surgical strategy, electrophysiological monitoring setting and outcome. All operations were performed under continuous neuro-monitoring via a retro-sigmoid approach by an interdisciplinary oto-neuro-surgical team led by three experienced neurosurgical skull base surgeons. Standardized documentation of auditory and facial functions before and after surgery, of intra- and postoperative sequels and complications was the basis for this analysis. Surgical steps consisted of tumor enucleation, opening of the auditory canal, partial or complete intrameatal resection and complete or gross total or only partial extrameatal resection.
Results: While 34% of patients had small tumors without brainstem involvement, two thirds (66%) suffered from large T3B to T4 tumors. Anatomical facial and cochlear nerve preservation rates were 98% and 63% respectively. Preserved auditory function was documented in 432 (72%) before and in 141 patients after surgery (32%). Hearing and facial nerves outcome correlated significantly with tumor size (p<0.001/p<0.05). Preservation rates were significantly higher in patients with Neurofibromatosis Type 2 or other contralateral otologic disease in whom partial intrameatal tumor resection and gross total extrameatal resection were performed leading to an average of 46% preservation and even 62% in small tumors. Furthermore, electrophysiological monitoring in these patients included multimodality tools by conventional and nearfield techniques.
Conclusion: Tumor size remains an important risk factor in VS surgery in general and with regard to functional outcome. As auditory function is regarded as most precious especially in bilateral tumor constitution (NF2) or only one hearing ear, in these patients more advanced attempts for preservation of function were undertaken. Nerve decompression, by bony opening of the auditory meatus and by partial or complete tumor resection, provides a significant chance and should be considered whenever auditory function is regarded as most valuable.