Association between improvement of clinical signs and decrease of ventricular volume after ventriculoperitoneal shunting in dogs with internal hydrocephalus

Background One of the remaining questions in treating dogs with internal hydrocephalus is the association between the decrease of ventricular volume and re-expansion of cerebral parenchyma with clinical improvement. Hypothesis A decrease in ventricular volume and re-expansion of brain tissue occur after ventriculoperitoneal shunting (VPS). Clinical improvement defined by resolution of >= 1 clinical signs is associated with decreased size of cerebral ventricles and that the extent of change in ventricular size is associated with clinical improvement. Animals Forty-five client-owned dogs with newly diagnosed communicating internal hydrocephalus. Methods Ventricular volume, brain volume, and clinical status of dogs that underwent VPS were measured before and 3 months after surgery. Multiple logistic regression analysis was performed to assess the influence of decrease in ventricular size in addition to the covariates "age of the animal" and "duration of clinical signs before surgery" on improvement of clinical signs. Results Decreased volume of cerebral ventricles was associated with resolution of >= 1 preoperative clinical sign (P < .003). The covariates "age of the animal" and "duration of clinical signs" were not associated with improvement of clinical signs. The percentage decrease in ventricular size was associated with resolution of ataxia (P = .008) and obtundation (P = .011). Conclusion and Clinical Importance The decrease in ventricular volume and increase in brain parenchyma after VPS are associated with improvement in clinical signs.