Hariharan P, Sondheimer J, Petroj A, et al. - This research sought to define the histological features of ventricular catheters (VCs) obstructions and distinguish links to clinical factors. Researchers obtained 343 VCs with relevant clinical data from five centers. After macroscopic analysis, each hole on the VCs was classified by the degree of tissue obstruction. Immunofluorescent labelling, histology, and immunohistochemistry were used to examine a subgroup of 54 samples. The data indicate that the age of the first surgery and the length of time a VC is implanted are factors that influence the degree of VC obstruction. The outcomes demonstrate that the tissue aggregates obstructing VCs are composed predominantly of astrocytes and macrophages; microglia have a relatively small presence.