Endoscopic Surgery for Deeply Located Intracranial Cysts: Risk Factors for Re-Operation and Symptom Improvement.

Purpose: We investigated the results of endoscopic fenestration for deeply located intracranial cysts (DLICs), risk factors for re-operation, and symptom improvement.

Materials And Methods: We included 51 patients with DLICs who underwent endoscopic fenestration between November 2006 and October 2022. The median age was 5±20 years (6 days-67 years), and 36 (70.6%) patients were aged <20 years. The male-to-female ratio was 1.3:1. The ventriculoscope was used to fenestrate the cysts, which had diameters under 4.5 mm. The volume of DLICs was measured separately on serial magnetic resonance imaging, and the patients were followed up for 32±40 months.

Results: The mean preoperative volume of DLICs was 63.5±87.4 cm³, which decreased to 23.7±56.2 cm³ postoperatively, with a 45.4%±32.1% decrease rate in 32 months. All DLICs were approached appropriately, avoiding the eloquent areas. Overall, 39 (76.5%) patients showed symptom improvement after a single operation, which was preserved without recurrence, whereas 12 (23.5%) underwent a second operation [shunting (17.6%) or repeating the endoscopic fenestration (5.9%)] owing to symptom aggravation and recurrent cysts. Patients aged <12 months showed 7.4 times more re-operation rate (=0.046) and 7.4 times less symptom improvement (=0.038) compared to those with older age. Females showed 6.5 times more re-operation rate (=0.037) and 7.1 times less symptom improvement (=0.027) than males. No patients experienced complications such as cerebrospinal fluid leakage, postoperative hemorrhage, or infection.

Conclusion: Endoscopic surgery is feasible for the treatment of DLICs. Female sex and age <12 months are risk factors for re-operation and less symptom improvement.