A uncommon side effect of ventriculoperitoneal shunt surgery is trapped fourth ventricle, often referred to as isolated fourth ventricle, which is marked by blockage of the cerebral aqueduct or exit. Cerebrospinal fluid accumulates as a result. According to this case report, a 7-year-old patient with a history of ventriculoperitoneal shunt developed a trapped fourth ventricle and manifested memory loss, weakness, and abnormal gait. To allow for the outflow of cerebrospinal fluid from the fourth ventricle, the patient had arachnoid dissection (adhesiolysis) and open posterior fenestration of the fourth ventricle’s midline. After a ten-day hospital stay, the patient was released following a successful surgery. In order to avoid major difficulties, this research emphasises the importance of early detection and treatment of a trapped fourth ventricle.