2025 Poster Presentations
P022: TRIGEMINAL SCHWANNOMAS TREATED VIA A LATERAL ORBITOTOMY APPROACH: OUTCOMES AND LIMITATIONS
Maria Karampouga, MD1; Bhuvic Patel, MD1; I-sorn Phoominaonin, MD1; Garret Choby, MD2; Eric W Wang, MD2; Tonya S Stefko, MD3; Carl H Snyderman, MD, MBA2; Georgios A Zenonos, MD1; Paul A Gardner, MD1; 1Department of Neurological Surgery, Center for Cranial Base Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA; 2Department of Otolaryngology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA; 3Department of Ophthalmology, Center for Cranial Base Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
Objective: Trigeminal Schwannomas (TSs) are rare, mostly benign tumors that exhibit an indolent clinical course. The microscopic lateral orbitotomy approach (LOA) with or without endoscopic assistance has emerged as a novel skull base corridor; however, its indications for the treatment of TSs have not been elucidated thus far. Herein we sought to evaluate the technical feasibility and the challenges encountered with the LOA in the surgical management of TSs.
Methods: All TS cases that underwent LOA through a lateral canthal incision the last decade in our department were retrospectively reviewed. Clinical outcomes are analyzed, and the surgical technique explained.
Results: Seven patients (4 females) with an average age of 34 years underwent LOA for TSs. Mean maximum tumor diameter was 2.8cm (range: 1.8-3.7). Six were primary, one was recurrent and one patient had neurofibromatosis type 2. All tumors were predominantly in middle cranial fossa, with four having either a small or medium posterior fossa component (5 Samii Grade A, 2 Grade C) (FIG.1). Presenting symptoms included trigeminal neuralgia (n=6), facial hypoesthesia (n=5), headache (n=4) and double vision (n=2). All patients underwent gross (n=5) or near total (n=2) resection. Neuralgia, while not exacerbated, reappeared in 4 patients after surgery and was ameliorated with medication. Two patients sustained new trigeminal hypoesthesia, and preoperative abducens palsy improved in both patients. No orbital complications, stroke, cerebrospinal fluid leak or mortalities occurred. Two lesions had minor recurrence during a mean follow-up of 42 months. The first underwent radiosurgery 6 years postoperatively and the second is under close surveillance.
Conclusion: Minimally invasive LOA stands as a plausible surgical corridor for addressing TSs of the middle cranial fossa, even with posterior fossa extension. Additional study is required, as the approach may be limited for tumors with significant posterior or infratemporal fossa involvement.
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FIG.1: Pre- and post-operative images of a Samii Grade C trigeminal schwannoma case treated via a lateral orbitotomy approach.