4th ventricular entrapment as a surgical entity: Case report with review of the literature discussing different treatment modalities

Introduction: Entrapped fourth ventricle (EFV) is a rare entity that has been reported previously as double compartment hydrocephalus, isolated fourth ventricle, encysted fourth ventricle, and trapped fourth ventricle. EFV typically arises as an adverse effect of brain hemorrhages, infections, or inflammation. The mainstay definitive treatment for EFV is surgery. Methods: We present the case of a 23-year-old female patient with hydrocephalus secondary to meningitis, for which a ventriculoperitoneal (VP) shunt was placed. The patient had previously undergone 11 VP shunt revisions for recurrent catheter occlusions, after which she developed EFV and subsequently underwent surgery. This procedure was complicated by catheter misplacement. At our institute, imaging demonstrated persistent EFV with a catheter misplaced into the brain parenchyma. We describe our treatment approach supported by a literature review. The review was a narrative, non-systematic review conducted across PubMed, Medline, Scopus, and ScienceDirect up to October 1, 2024. Keywords included “aqueductal stenosis,” “double compartment hydrocephalus,” “isolated fourth ventricle,” “trapped fourth ventricle,” “fourth ventricular entrapment,” “encysted fourth ventricle,” “ventriculoperitoneal shunt,” “ventriculopleural shunt,” “neuroendoscopic surgery,” “endoscopic aqueductal stenting,” “endoscopic aqueductoplasty,” “endoscopic interventriculostomy,” and “foramen magnum decompression.” Literature was searched to identify reported EFV cases and surgical treatment modalities. Articles were selected based on relevance, and reference lists were reviewed for additional studies. Only English-language articles were included. No formal inclusion or exclusion criteria, predefined search strategy, or PRISMA methodology were applied, as the review aimed to provide a descriptive overview of reported management strategies rather than a systematic synthesis. Treatment modalities were summarized based on the reviewed literature. Conclusion: Treatment of EFV remains elusive. Surgery remains the definitive management, with a variety of surgical techniques. It is crucial to maintain close follow-up for patients, and to have tight selection criteria for whether patients should be referred to surgery or not, based on their clinical presentation.