Trigeminal Schwannoma: A Retrospective Analysis of Endoscopic Endonasal Management, Treatment Outcomes, and Neuropathic Sequelae

Background: Schwannomas are benign, slow-growing tumors of ectodermal origin derived from Schwann cells. Trigeminal schwannomas (TS) are a rare clinical entity, constituting ~0.07 to 0.3% of all intracranial tumors and 0.8 to 5% of intracranial schwannomas. Common presenting symptoms of TS include facial hypoesthesia, pain, and paresthesia. Previous reports of functional outcomes following endoscopic endonasal approach (EEA) TS resection are favorable with a low rate of surgical complications. Despite these advances, limited information exists regarding the neuropathic sequelae associated with TS surgery.

Objective: Evaluate the clinical presentation, treatment outcomes, and neuropathic sequelae of TS surgery. Specifically, symptoms before and after EEA TS resection were examined as well as the necessity for long-term pharmacologic agents, adjunctive therapies, and pain specialist interventions.

Methods: Retrospective review (2004–2020) at a single academic institution revealing 16 patients who underwent EEA TS resection.

Results: Thirteen patients underwent single-stage EEA (n = 5 with anterior transmaxillary approach) and three patients required multistage surgery in the form of EEA (n = 1) or craniotomy (n = 2). Mean age at time of surgery was 43.4 years with a slight female (1.83:1) predominance. Primary symptomatology includes facial pain (n = 5, 31.3%), facial hypoesthesia (n = 4, 25.0%), headache (n = 4, 25.0%), and diplopia (n = 2, 12.5%). Two patients carried a preoperative diagnosis of migraines (n = 2, 12.5%). Preoperative analgesics include neuromodulators (n = 4, 25.0%), COX inhibitors (n = 3, 18.8%), and narcotics (n = 2, 12.5%). Eight patients (50.0%) underwent gross total resection, 4 patients (25.0%) underwent near total (>90%) resection, and four patients (25.0%) underwent subtotal resection. Surgical complications include transient abducens palsy (n = 2), ICA injury (n = 1), and transient vagus palsy (n = 1). Mean follow-up was 59.8 months, with an average of two CT and six MRI surveillance scans. Following TS surgery, patients were found to have persistent hypoesthesia (n = 12, 85.7%), mastication musculature atrophy (n = 3, 21.4%), and facial paresthesia (n = 2, 14.2%). One patient (6.3%) required repeat EEA and stereotactic radiosurgery for recurrent disease and four patients (25.0%) underwent stereotactic radiosurgery for persistent disease. TS patients with preoperative analgesic utilization (n = 3) were significantly more likely to trial adjunctive therapies (p = 0.013) such as acupuncture, nerve blocks, botulinum toxin injections, and chiropractic manipulation and seek intervention with pain specialists (p = 0.013). Similarly, TS patients with migraines (n = 2) were significantly more likely to require prolonged neuromodulator utilization (p = 0.009), trial adjunctive therapies (p = 0.002), develop a postoperative pain syndrome (p = 0.025), and explore evaluation by both neurologists (p = 0.009) and pain specialists (p = 0.002). Finally, TS patients with preoperative facial pain (n = 5) were also significantly more likely to trial adjunctive therapies (p = 0.004) and seek consultation with neurologists (p = 0.029) and pain specialists (p = 0.004).

Conclusion: This series is the first to demonstrate the long-term neuropathic sequelae associated with EEA for TS resection. Factors that appear to play a role in the development of trigeminal dysfunction include preoperative facial pain, medication utilization, and preexisting pain or headache syndromes. Additional prospective studies are necessary to further elucidate the natural history of trigeminal neuropathy as well as develop a standardized grading system to accurately assess trigeminal dysfunction.

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Artikel online veröffentlicht:
12. Februar 2021