Internal hydrocephalus can be effectively treated in dogs and cats using a ventriculoperitoneal shunt, allowing affected animals long-term survival and improvement of neurological symptoms. Nevertheless, short- and medium-term complications may occur, some of which require revision surgery. Obstruction of the ventricular catheter represents a rare but clinically significant complication of VPS therapy in animals. The aim of the present study was to investigate clinical, imaging, and cerebrospinal fluid parameters in dogs with congenital internal hydrocephalus following implantation of a ventriculoperitoneal shunt system and to identify potential risk factors for the development of ventricular catheter obstruction. In particular, the study evaluated whether factors such as age, breed, body weight, imaging parameters (ventricle-to-brain ratio, catheter position), and CSF analytical findings (cell count, erythrocyte count, protein concentration, and cytological alterations) were associated with the occurrence of catheter obstruction. In addition, histopathological changes in explanted catheters were described to characterize possible pathophysiological mechanisms underlying obstruction development. The results of the logistic regression analysis revealed no significant association between the evaluated parameters and catheter obstruction. Postoperative alterations in cerebrospinal fluid parameters are best interpreted as part of a physiological response to surgical intervention, which in most cases resolves spontaneously over time. Future studies should be designed prospectively and in a standardized manner, and should be complemented by close longitudinal CSF monitoring as well as systematic histopathological examination of catheter tips in cases of shunt-related complications.
