Lateral Orbitotomy for Trigeminal Schwannomas: Surgical Technique, Outcomes, and Limitations

Trigeminal schwannomas (TSs) are rare, mostly benign tumors that exhibit an indolent clinical course. The lateral orbitotomy approach (LOA), with or without endoscopic assistance, has emerged as a novel skull base route, particularly for accessing lesions confined to the middle cranial fossa. Herein, we elucidate the advantages and limitations of the LOA for the treatment of TSs.

All TS cases that underwent LOA through a lateral canthus incision during the past decade in our department were retrospectively reviewed. The operative technique was detailed, and clinical outcomes were analyzed.

Eight patients (4 females) with an average age of 37 years underwent LOA for TSs. The mean maximum tumor diameter was 2.7 cm (range: 1.8-3.7 cm). Seven were primary and one was recurrent, the latter in a patient with neurofibromatosis type 2. All tumors were predominantly in the middle cranial fossa, with 4 having either a small or medium posterior fossa component (6: Samii Type A; 2: Type C). Presenting symptoms included trigeminal neuralgia (n = 6), facial hypoesthesia (n = 6), headache (n = 5), and double vision (n = 3). All patients underwent gross (n = 6) 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 either improved or resolved in all 3 cases. No orbital complications, cerebrospinal fluid leak, or mortalities occurred. Two lesions had minor recurrence during a mean follow-up of 42.9 months. The first underwent radiosurgery 6 years postoperatively and the second is under close surveillance.

Minimally invasive LOA stands as a plausible and aesthetically favorable surgical corridor for addressing TSs of the middle cranial fossa, even with extension into the posterior fossa. However, additional study is required as the approach may be limited for tumors with significant posterior or infratemporal fossa involvement.