Microsurgical outcomes for vestibular schwannomas associated with trigeminal neuralgia

Trigeminal neuralgia (TN) is a disorder characterized by recurrent, severe, brief pain in the distribution of the trigeminal nerve. Secondary TN may be caused by tumors in the cerebellopontine angle (CPA), including vestibular schwannomas (VS), which are benign tumors originating from the Schwann cells of the vestibular nerve. While treatment options for TN include pharmacological therapy, radiofrequency ablation and microvascular decompression (MVD), there is no established gold standard for treating TN secondary to VS. This study aims to present clinical outcomes, including pain and numbness relief, following microsurgical treatment for 63 patients with VS and concurrent TN, while also analyzing potential factors influencing preoperative and postoperative symptom severity. A retrospective review of 63 patients with VS-associated secondary TN who underwent microsurgical treatment at Xuanwu Hospital, Capital Medical University, from December 2018 to May 2024. Patient demographics, clinical features, surgical approach, and outcomes were analyzed. All patients underwent routine preoperative imaging, and Koos grading system is used to describe the tumor size and its impact on surrounding structures. Facial nerve function was assessed using the House-Brackmann (H-B) scale. Pain and numbness were evaluated using the Barrow Neurological Institute (BNI) pain and numbness scores. Among the 63 patients, 95.2% achieved complete pain relief at the final follow-up, while 72.2% of patients with preoperative numbness achieved relief, while 15.6% without prior numbness developed new numbness postoperatively. Neurovascular compression (NVC) was identified in 20 patients (31.7%), with the superior cerebellar artery (SCA) as the offending vessel in 19 cases (95%) and the petrosal vein (PV) in 1 case (5%). Neither tumor size nor neurovascular compression (NVC) correlated significantly with preoperative pain (P = 0.963, P = 0.269) or numbness (P = 0.581, P = 0.626). Good facial nerve function was preserved in 87.3% of patients, with 25% of patients maintaining serviceable hearing postoperatively. Surgical complications occurred in 12.7% of cases, including 1 intracranial infection and 7 new numbness. No cases of intracranial hemorrhage or cerebrospinal fluid leakage were reported. Microsurgery is an effective treatment for VS-associated TN, providing high rates of pain and numbness relief while preserving neurological function. In these cases, the superior cerebellar artery was the predominant vessel responsible for NVC. Tumor size and the presence of NVC did not significantly correlate with the severity of preoperative symptoms. While some patients developed new postoperative numbness, facial nerve preservation was favorable, and surgical complications were minimal. Surgical outcomes indicate that microsurgical approaches, including MVD when necessary, are effective for patients with VS-associated secondary TN.