Surgical Management Strategy for Large Cystic Vestibular Schwannoma Based on the Cyst Classification

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Cystic vestibular schwannomas often grow more rapidly and adhere more strongly to the facial nerves and brainstem than do solid tumors. Patients with large cystic tumors may experience sudden clinical deterioration during the preoperative waiting period; furthermore, it is important to carefully consider whether to dissect the cyst wall from adjacent structures. Accordingly, we aimed to clarify the influence of different cyst types on surgical strategies. We included 19 patients with large cystic vestibular schwannomas (extrameatal diameter >30 mm) who underwent microsurgical resection. Tumors were classified using the Piccirillo et al. system based on the cyst location and wall thickness. We compared the incidence of sudden clinical deterioration and surgical outcomes according to the cyst types. Peripherally located thin-walled cysts (type B) were significantly more likely to cause sudden clinical deterioration than were centrally located thick-walled cysts (type A). In addition, when the thin cyst wall was firmly adhered to the facial nerve or brainstem, a conservative surgical strategy was applied, with the wall being intentionally left in place rather than attempting forceful dissection. This approach achieved excellent facial nerve preservation but relatively decreased the extent of resection. Taken together, these findings suggest that large cystic vestibular schwannomas with peripherally located thin-walled cysts have a high risk of rapid clinical deterioration and may require early surgical intervention. It is important to adapt the dissection strategy according to cyst wall thickness to achieve optimal postoperative preservation of the facial nerve.