Endoscopic subtemporal keyhole anterior transpetrosal approach in small cerebellopontine angle tumors with trigeminal neuralgia: A case series of three patients.

Background: Surgical management of cerebellopontine angle (CPA) lesions remains challenging due to the region's complex anatomy. The microscopic anterior transpetrosal approach or combined petrosectomy is the standard technique for trigeminal schwannomas and CPA meningiomas, but requires extensive craniotomy and dissection. For smaller tumors, the endoscopic anterior transpetrosal approach (eATPA) offers a less invasive alternative, providing access to the petrous apex and Meckel cave with minimal temporal lobe retraction. This report presents the initial experience in Indonesia utilizing the keyhole eATPA technique, assessing feasibility, safety, and outcomes.

Case description: In 2024, three patients with ~2 cm CPA lesions compressing the trigeminal nerve-one trigeminal schwannoma and two CPA meningiomas-underwent eATPA using a pure endoscopic four-hands technique. The procedure included a 3 cm subtemporal craniotomy, intradural identification of the Greater Superficial Petrosal Nerve with intraoperative monitoring, drilling of Kawase triangle, opening of Meckel cave, tumor resection, and trigeminal nerve decompression. Total resection and successful decompression were achieved in all cases. Trigeminal neuralgia improved: The two CPA meningioma patients experienced complete pain relief, while the schwannoma patient had residual facial numbness. Operative time was 4-5 h due to the learning curve, with minimal bleeding, no cerebrospinal fluid leakage, and no new neurological deficits. Patients reported mild incisional pain and were discharged within 3 days. At 3-6 months' follow-up, all remained clinically stable.

Conclusion: This early experience suggests the keyhole eATPA technique is a feasible, safe, and effective approach for small CPA lesions, offering favorable clinical outcomes and faster post-operative recovery.