Proposed radiological score for the evaluation of isolated fourth ventricle treated by endoscopic aqueductoplasty

Purpose Evidence supporting the effectiveness of endoscopic aqueductoplasty (EA) for the treatment of isolated fourth ventricle (IFV) is limited to small surgical series of cases. Additionally, studies adopted different radiological outcome criteria, which makes it difficult to compare outcomes accurately. Thus, we aimed to develop a radiological score (RS) as an alternative assessment method for EA. Methods The cases of 20 consecutive pediatric patients harboring IFV and treated by EA were retrospectively reviewed. Clinical data and pre- and 1-year postoperative brain images were analyzed. The RS was based on the enlargement of the fourth ventricle and deformation of the cerebellum and brainstem. After randomization, three experts, blinded to patient outcomes, analyzed the brain images and established a consensus for the values of the score. Outcomes were validated by comparing the maximum anteroposterior distance of the fourth ventricle using the RS, pediatric functional status score, and clinical symptoms. Results The RS was strongly correlated with the anteroposterior distance of the fourth ventricle (Pearson's coefficient = 0.78), and the mean RS dropped from 6.15 to 3.90 (p < 0.001) 1 year after EA. Upward extension (p = 0.021) and brainstem deformation (p = 0.010) were the most significant improved features. There was agreement among RS and symptom improvement in 16 children (80%) and the pediatric functional status score in 14 children (70%). Conclusion In this study, the proposed radiological score proved to be an accurate tool for the evaluation of IFV treatment with EA.