Internal hydrocephalus is the most common congenital anomaly of the nervous system in dogs.1,2 A mismatch between production and absorption leads to accumulation of CSF, dilation of the ventricular system, and subsequent increases in intraventricular and intracranial pressures.3–7 Obstructive or noncommunicating hydrocephalus is characterized by an occlusion within the ventricular system and entrapment of CSF rostral to the site of obstruction.8,9 The blockage of CSF flow occurs most often in the mesencephalic aqueduct and is usually caused by congenital abnormalities, inflammatory diseases, intraventricular hemorrhage, or the development of tumors.4,5,10,11 Inadequate absorption or increased production of CSF without impairment of outflow is referred to as communicating hydrocephalus.4,12,13 An overproduction of CSF is rare and can be the consequence of a choroid plexus neoplasia.14,15 The underlying cause of the decreased rate of CSF absorption has not been identified yet and is referred to as idiopathic normal-pressure hydrocephalus in human medicine.8,15 In veterinary medicine, congenital hydrocephalus seems to be more common than the acquired form and is detected predominantly in small and toy breeds of dog.1,4,5 The increased CSF pressure in patients with hydrocephalus eventually leads to focal destruction of the ependymal lining, compromise of cerebral vessels, damage to periventricular white matter, neuronal injury, and severe white matter atrophy.2,16,17
In affected dogs and cats, attempts to reduce CSF production through the use of glucocorticoids and diuretics offers only temporary improvement of clinical signs, and surgical treatment is indicated in most cases.3,4,18 Implantation of silicone-based shunt tubes provides CSF drainage from the cerebral ventricles to the peritoneal cavity or right atrium and compensates for the impaired absorption.3,19 Although this surgical procedure in companion animals19 was established 40 years ago, reports concerning the long-term outcome following shunt implantation in dogs with hydrocephalus are scarce.20 It is often quoted that shunt failure attributed to plugging by the choroid plexus, glial tissue, and proteinaceous material is common and a major factor in patient death, but the actual prevalence of these complications in small animals remains unknown.21,22 There is also little information about the improvement of neurologic signs after surgery in dogs and cats. Few case reports23,24 in which successful shunt placement and outcome of individual dogs are described have been published. In 1 study,20 treatment via ventriculoperitoneal shunting of 5 dogs with idiopathic hydrocephalus and 9 dogs with acquired hydrocephalus was analyzed. The aim of the study reported here was to examine outcome data for cats and a larger number of dogs with congenital internal hydrocephalus following treatment via ventriculoperitoneal shunting to determine treatment-associated change in neurologic signs, the nature and incidence of postoperative complications, and survival time. It was anticipated that the study findings would enable veterinarians to provide treatment recommendations and prognostic estimations to owners of dogs or cats with hydrocephalus.
SHUNT, Christoph Miethke GmbH & Co KG, Potsdam, Germany.
PaediGAV 4/14 or 9/19, Christoph Miethke GmbH & Co KG, Potsdam, Germany.
BMDP/Dynamic Release, version 7.0, Los Angeles, Calif.
2. Wünschmann A, Oglesbee M. Periventricular changes associated with spontaneous canine hydrocephalus. Vet Pathol 2001; 38: 67–73.
5. Dewey CW. Encephalopathies: disorders of the brain. In: Dewey CW, ed. A practical guide to canine and feline neurology. Ames, Iowa: Iowa State University Press, 2003;99–178.
6. Rekate HL. A contemporary definition and classification of hydrocephalus. Semin Pediatr Neurol 2009; 16: 9–15.
7. Rekate HL. The definition and classification of hydrocephalus: a personal recommendation to stimulate debate. Cerebrospinal Fluid Res 2008; 5: 2–7.
8. de Lahunta A. Cerebrospinal fluid and hydrocephalus. In: de Lahunta A, ed. Veterinary neuroanatomy and clinical neurology. 2nd ed. Philadelphia: WB Saunders Co, 1983;30–52.
9. Bering EA, Sato O. Hydrocephalus: changes in formation and absorption of cerebrospinal fluid within the cerebral ventricles. J Neurosurg 1963; 20: 1050–1063.
10. Turrel JM, Fike JR, LeCouteur RA, et al. Computed tomographic characteristics of primary brain tumors in 50 dogs. J Am Vet Med Assoc 1986; 188: 851–856.
14. Smith ZA, Moftakhar P, Malkasian D, et al. Choroid plexus hyperplasia: surgical treatment and immunohistochemical results. Case report. J Neurosurg 2007; 107(suppl 3): 255–262.
15. Pickard JD, Coleman MR, Czosnyka M. Hydrocephalus, ventriculomegaly and the vegetative state: a review. Neuropsychol Rehabil 2005; 15: 224–236.
17. James AE, Burns B, Flor WF, et al. Pathophysiology of chronic communicating hydrocephalus in dogs ( Canis familiaris). Experimental studies. J Neurol Sci 1975; 24: 151–178.
18. Simpson ST. Hydrocephalus. In: Kirk RW, Bonagura JD, eds. Current veterinary therapy X: small animal practice. Philadelphia: WB Saunders Co, 1989;842–847.
19. Gage ED, Hoerlein BF. Surgical treatment of canine hydrocephalus by ventriculoatrial shunting. J Am Vet Med Assoc 1968; 153: 1418–1431.
20. De Stefani A, De Risio L, Platt SR, et al. Surgical technique, postoperative complications and outcome in 14 dogs treated for hydrocephalus by ventriculoperitoneal shunting. Vet Surg 2011; 40: 183–191.
22. Browd SR, Ragel BT, Gottfried ON, et al. Failure of cerebrospinal fluid shunts: part 1: obstruction and mechanical failure. Pediatr Neurol 2006; 34: 83–92.
23. Kitagawa M, Ueno H, Watanabe S, et al. Clinical improvement in two dogs with hydrocephalus and syringomyelia after ventriculoperitoneal shunting. Aust Vet J 2008; 86: 36–42.
24. Dewey CW. External hydrocephalus in a dog with suspected bacterial meningoencephalitis. J Am Anim Hosp Assoc 2002; 38: 563–567.
26. Dewey CW, Coates JR, Ducote JM, et al. External hydrocephalus in two cats. J Am Anim Hosp Assoc 2003; 39: 567–572.
30. Wang PP, Avellino AM. Hydrocephalus in children. In: Rengachary SS, Ellbogen RG, eds. Principles of neurosurgery. 2nd ed. St Louis: Elsevier Mosby, 2005;117–135.
32. Vullo T, Manzo R, Gomez DG. A canine model of acute hydrocephalus with MR correlation. AJNR Am J Neuroradiol 1998; 19: 1123–1125.
33. Kriebel RM, Shah AB, McAllister JP. The microstructure of cortical neuropil before and after decompression in experimental infantile hydrocephalus. Exp Neurol 1993; 119: 89–98.
34. Luciano MG, Skarupa DJ, Booth AM, et al. Cerebrovascular adaptation in chronic hydrocephalus. J Cereb Blood Flow Metab 2001; 21: 285–294.
35. Hale PM, McAllister JP, Katz SD, et al. Improvement of cortical morphology in infantile hydrocephalic animals after ventriculoperitoneal shunt placement. Neurosurgery 1992; 31: 1085–1096.
37. Copeland GP, Foy PM, Shaw MD. The incidence of epilepsy after ventricular shunting operations. Surg Neurol 1982; 17: 279–281.
38. Bourgeois M, Sainte-Rose C, Cinalli G, et al. Epilepsy in children with shunted hydrocephalus. J Neurosurg 1999; 90: 274–281.
39. Kim JM, Park J, Kim J, et al. Treatment of hydrocephalus with high-pressure valve ventriculoperitoneal shunt in a dog. Jpn J Vet Res 2010; 58: 137–142.
40. Jäderlund KH, Hansson K, Berg AL, et al. Cerebral ventricular size in developing normal kittens measured by ultrasonography. Vet Radiol Ultrasound 2003; 44: 581–588.
41. Spoulding KA, Sharp NJ. Ultrasonographic imaging of the lateral cerebral ventricles in the dog. Vet Radiol Ultrasound 1990; 31: 59–64.
42. De Haan C, Kraft SL, Gavin PR, et al. Normal variation in size of the lateral ventricles in the Labrador Retriever dog as assessed by magnetic resonance imaging. Vet Radiol Ultrasound 1994; 35: 83–86.
43. Kii S, Uzuka Y, Taura Y, et al. Magnetic resonance imaging of the lateral ventricles in Beagle-type dogs. Vet Radiol Ultrasound 1997; 38: 430–433.
44. Vite CH, Insko EK, Schotland HM, et al. Quantification of cerebral ventricular volume in English Bulldogs. Vet Radiol Ultrasound 1997; 38: 437–443.
46. Keucher TR, Mealey J. Long-term results after ventriculoatrial and ventriculoperitoneal shunting for infantile hydrocephalus. J Neurosurg 1979; 50: 179–186.
47. Di Rocco C. The surgical treatment. In: Di Rocco C, ed. The treatment of infantile hydrocephalus. 3rd ed. Boca Raton, Fla: CRC Press, 1987;81.
48. O'Brien MS, Harris ME. Long-term results in the treatment of hydrocephalus. Neurosurg Clin North Am 1993; 4: 625–632.
49. Noetzel MJ, Baker RP. Shunt fluid examination: risks and benefits in the evaluation of shunt malfunction and infection. J Neurosurg 1984; 61: 328–332.
50. Sainte-Rose C, Hoffman HJ, Hirsch JF. Shunt failure. In: Marlin AE, ed. Concepts in pediatric neurosurgery. Vol 9. Basel, Switzerland: Karger, 1989;7–20.
51. Piatt JH, Carlson CV. A search for determinants of cerebrospinal fluid shunt survival: retrospective analysis of a 14-year institutional experience. Pediatr Neurosurg 1993; 19: 233–241.
52. Iskandar BJ, Tubbs S, Mapstone TB, et al. Death in shunted hydrocephalic children in the 1990s. Pediatr Neurosurg 1998; 28: 173–176.
53. McGirt MJ, Leveque JC, Wellons JC III, et al. Cerebrospinal fluid shunt survival and etiology of failures: a seven-year institutional experience. Pediatr Neurosurg 2002; 36: 248–255.
54. Liptak GS, McDonald JV. Ventriculoperitoneal shunts in children: factors affecting shunt survival. Pediatr Neurosci 1985; 12: 289–293.
56. Tuli S, Drake J, Lawless J, et al. Risk factors for repeated cerebrospinal shunt failures in pediatric patients with hydrocephalus. J Neurosurg 2000; 92: 31–38.
57. Kestle J, Drake J, Milner R, et al. Long-term follow-up data from the Shunt Design Trial. Pediatr Neurosurg 2000; 33: 230–236.
58. McGirt MJ, Zaas A, Fuchs HE, et al. Risk factors for pediatric ventriculoperitoneal shunt infection and predictors of infectious pathogens. Clin Infect Dis 2003; 36: 858–862.
59. Stein SC, Guo W. Have we made progress in preventing shunt failure? A critical analysis. J Neurosurg Pediatr 2008; 1: 40–47.
61. Drake JM, Kestle JR, Milner R, et al. Randomized trail of cerebrospinal fluid shunt valve design in pediatric hydrocephalus. Neurosurgery 1998; 43: 294–305.
62. Appelgren, T, Zetterstrand S, Elfversson J, et al. Long-term outcome after treatment of hydrocephalus in children. Pediatr Neurosurg 2010; 46: 221–226.
64. Renier D, Lacombe J, Pierre-Kahn A, et al. Factors causing acute shunt infection: computer analysis of 1174 operations. J Neurosurg 1984; 61: 1072–1078.
66. Choux M, Genitori L, Lang D, et al. Shunt implantation: reducing the incidence of shunt infection. J Neurosurg 1992; 77: 875–880.
69. Lautersack O, Jödicke A, Tacke S, et al. Hydrozephalus bei Hund und Katze—Therapeutische Möglichkeiten und erste eigene Erfahrungen. Kleintierpraxis 2003; 48: 461–528.
70. Bentz BG, Moll HD. Treatment of congenital hydrocephalus in a foal using a ventriculoperitoneal shunt. J Vet Emerg Crit Care 2008; 18: 170–176.
71. Kitagawa M, Kanayama K, Sakai T. Subdural accumulation of fluid in a dog after the insertion of a ventriculoperitoneal shunt. Vet Rec 2005; 156: 206–208.
72. Pudenz RH, Foltz EL. Hydrocephalus: overdrainage by ventricular shunts. A review and recommendations. Surg Neurol 1991; 35: 200–212.
73. Yamada S, Ducker TB, Perot PL. Dynamic changes of cerebrospinal fluid in upright and recumbent shunted experimental animals. Childs Brain 1975; 1: 187–192.