Development of a Four-Parameter Preoperative Pilot Risk Score for Predicting Postoperative Shunt Dependency After Endoscopic Resection of Symptomatic Third Ventricular Colloid Cysts.

OBJECTIVE: Persistent hydrocephalus may develop after surgery for symptomatic third ventricular colloid cysts (TVCC), requiring ventriculoperitoneal (VP) shunting. No existing scoring system predicts this outcome. We developed a four-parameter preoperative pilot risk score to predict postoperative shunt dependency. METHODS: In this retrospective study, 29 symptomatic TVCC patients who underwent endoscopic surgery (16 males, 13 females; median age 40, range 11-66) were evaluated using preoperative MRI. Four risk factors were identified: cyst location (Zone I or III), cyst volume ≥6.0 cm3, third ventricular volume ≥7.8 cm3 (ROC-derived thresholds), and T2-weighted hypointensity. Each factor was assigned 1 point, yielding an exploratory pilot risk score (0-4) intended for hypothesis-generating risk stratification rather than as a definitive clinical scoring system. RESULTS: VP shunt was required in 4/29 (14%). Using a cutoff of ≥2, the pilot risk score correctly identified all four shunt cases (sensitivity 100%), with a specificity of 56%, a positive predictive value (PPV) of 27%, a negative predictive value (NPV) of 100%, and an Area Under the Curve (AUC) of 0.800. CONCLUSIONS: In this pilot study, our findings suggest that the clinically derived pilot risk score, despite the lack of statistical significance for individual predictors, may serve as a hypothesis-generating tool to support clinical decision-making pending external validation. Patients with a pilot risk score of ≥2 represent a high-risk group in whom adjunctive endoscopic third ventriculostomy (ETV) or early shunt preparation may be considered. External validation in larger prospective cohorts is warranted.