Outcome of ventriculoperitoneal shunt implantation for treatment of congenital internal hydrocephalus in dogs and cats: 36 cases (2001-2009).

OBJECTIVE: To examine outcome data for cats and dogs with congenital internal hydrocephalus following treatment via ventriculoperitoneal shunting to determine treatment-associated changes in neurologic signs, the nature and incidence of postoperative complications, and survival time. DESIGN: Retrospective multicenter case series. ANIMALS: 30 dogs and 6 cats with congenital internal hydrocephalus (confirmed via CT or MRI). PROCEDURES: Medical records for dogs and cats with internal hydrocephalus that underwent unilateral ventriculoperitoneal shunt implantation from 2001 through 2009 were evaluated. Data collected included the nature and incidence of postoperative complications, change in clinical signs following surgery, and survival time. To compare pre- and postoperative signs, 2-way frequency tables were analyzed with a 1-sided exact McNemar test. RESULTS: 8 of 36 (22%) animals developed postoperative complications, including shunt malfunction, shunt infection, and seizure events. Three dogs underwent shunt revision surgery. Thirteen (36%) animals died as a result of hydrocephalus-related complications or were euthanized. Following shunt implantation, clinical signs resolved in 7 dogs and 2 cats; overall, 26 (72%) animals had an improvement of clinical signs. After 18 months, 20 animals were alive, and the longest follow-up period was 9.5 years. Most deaths and complications occurred in the first 3 months after shunt placement. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that ventriculoperitoneal shunt implantation is a viable option for treatment of dogs or cats with congenital hydrocephalus. Because complications are most likely to develop in the first 3 months after surgery, repeated neurologic and imaging evaluations are warranted during this period.

Evaluation of the volumes of cranial cavities in Cavalier King Charles Spaniels with Chiari-like malformation and other brachycephalic dogs as measured via computed tomography.

OBJECTIVE-To measure the absolute and relative volumes of cranial vaults of Cavalier King Charles Spaniels (CKCSs) and other brachycephalic dogs for the purpose of evaluating a possible association between the volume of the caudal fossa (fossa caudalis cerebri; CF) and existence of Chiari-like malformation (CLM) and syringohydromyelia in CKCSs. ANIMALS-40 CKCSs and 25 brachycephalic dogs. PROCEDURES-The intracranial vault of all dogs was evaluated via computed tomography followed by magnetic resonance imaging. Volumes of the CF and the rostral and medial fossa (fossa rostralis et medialis cerebri) were determined. The ratio of the absolute volumes was calculated as the volume index (VI). RESULTS-All CKCSs had cranial characteristics consistent with CLM. There were no significant differences between CKCSs and brachycephalic dogs with respect to the VI and absolute volumes of the CF and rostral and medial fossas. The CKCSs without syringohydromyelia (n = 26) had a median VI of 0.1842, and CKCSs with syringohydromyelia (14) had a median VI of 0.1805. The median VI of other brachycephalic dogs was 0.1864. The VI did not differ among these 3 groups. CONCLUSIONS AND CLINICAL RELEVANCE-Results of this study suggested that descent of the cerebellum into the foramen magnum and the presence of syringohydromyelia in CKCSs are not necessarily associated with a volume reduction in the CF of the skull.