[Endoscopic resection of type D trigeminal schwannoma through nasal sinus approach]

Objective: To examine the feasibility and surgical approach of removing type D trigeminal schwannoma through nasal cavity and nasal sinus under endoscope. Methods: Eleven patients with trigeminal schwannoma who were treated in the Department of Otorhinolaryngology, Qilu Hospital of Shandong University from December 2014 to August 2021 were analyzed retrospectively in this study. There were 7 males and 4 females, aged (47.5±13.5) years (range: 12 to 64 years). The neoplasm involved the pterygopalatine fossa, infratemporal fossa, ethmoidal sinus, sphenoid sinus, cavernous sinus, and middle cranial fossa. The size of tumors were between 1.6 cm×2.0 cm×2.0 cm and 5.7 cm×6.0 cm×6.0 cm. Under general anesthesia, the tumors were resected through the transpterygoid approach in 4 cases, through the prelacrimal recess approach in 4 cases, through the extended prelacrimal recess approach in 2 cases, and through the endoscopic medial maxillectomy approach in 1 case. The nasal endoscopy and imaging examination were conducted to detect whether neoplasm recurred or not, and the main clinical symptoms during follow-up. Results: All the surgical procedures were performed under endonasal endoscope, including Gross total resection in 10 patients. The tumor of a 12-year-old patient was not resected completely due to huge tumor size and limited operation space. One patient was accompanied by two other schwannomas located in the occipital region and the ipsilateral parotid gland region originating from the zygomatic branch of the facial nerve, both of which were removed concurrently. After tumor resection, the dura mater of middle cranial fossa was directly exposed in the nasal sinus in 2 cases, including 1 case accompanied by cerebrospinal fluid leakage which was reconstructed by a free mucosal flap obtained from the middle turbinate, the other case was packed by the autologous fat to protect the dura mater. The operation time was (M(IQR)) 180 (160) minutes (range: 120 to 485 minutes). No complications and deaths were observed. No recurrence was observed in the 10 patients with total tumor resection during a 58 (68) months' (range: 10 to 90 months) follow-up. No obvious change was observed in the facial appearance of all patients during the follow-up. Conclusion: Type D trigeminal schwannoma involving pterygopalatine fossa and infratemporal fossa can be removed safely through purely endoscopic endonasal approach by selecting the appropriate approach according to the size and involvement of the tumor.