▲ Professor Young-Hoon Kim (right) is explaining the treatment process to a patient with a lower cranial nerve schwannoma before Gamma Knife radiosurgery.

Gamma Knife radiosurgery is a treatment used for inoperable brain disease cases, which involves focusing high-energy gamma radiation on brain lesions without making an incision in the head. Gamma knife radiosurgery is also used to treat ‘lower cranial nerve schwannoma,’ a tumor located in the lower brain. However, there has been a lack of long-term analysis of the treatment effect due to the disease’s low incidence, accounting for only about 1% of all brain tumors in South Korea.

A research team led by Professor Young-Hoon Kim of the Department of Neurosurgery at Asan Medical Center analyzed the findings of 60 patients who underwent Gamma Knife radiosurgery for lower cranial nerve schwannoma over an average follow-up period of 53 months. The analysis revealed tumor growth inhibition in 55 patients (approx. 91.6%), demonstrating significant therapeutic efficacy. In the subgroup analysis by disease, tumor growth inhibition was shown in 43 (91.5%) out of 47 patients with jugular foramen schwannoma and 12 out of 13 patients with hypoglossal nerve schwannoma. The one-, two-, and three-year postoperative disease-free survival rates were 96.5%, 91.5%, and 89.0%, respectively.

A further analysis was performed on neurologic symptoms resulting from lower cranial nerve schwannoma treatment, such as severe dysphagia, ataxia, or hearing impairment, after the follow-up period. Among the 60 patients, 30 experienced improvements, and 20 remained stable. Symptoms temporarily worsened in 7 patients but recovered without major problems, and only 3 patients experienced aggravated symptoms.

The study findings were recently published in the ‘Journal of Neurosurgery,’ an international academic journal of neurosurgery.