Spinal arachnoid pseudocysts in 10 rottweilers

Abstract

Ten rottweilers presenting with spinal arachnoid pseudocysts were investigated. In six dogs, the lesions were localised dorsally at C2-C3; in three dogs, dorsally and ventrally at C5-C6; and, in one dog, dorsally and ventrally at C6-C7. Clinical signs were consistent with focal compression of the affected spinal cord segments. The animals showed ataxia of all four limbs, with truncal ataxia and marked hypermetria in cases of C2-C3 involvement, or ambulatory tetraparesis in cases of C5-C6 or C6-C7 involvement. Other than signs indicative of spina bifida in one dog, no abnormalities could be detected on plain radiographs. Myelography was used to define the localisation and extent of the pseudocysts. Additional information was obtained using magnetic resonance imaging in five dogs. Five dogs underwent a dorsal laminectomy; in three cases, the pseudocyst was treated by marsupialisation and, in two, by durectomy.

Severe focal myelopathy secondary to chronic compression by an arachnoid pseudocyst in a Rottweiler

“…However, both in humans and dogs, a complete block of contrast medium flow at the lesion site similar to what was seen in the present case has also been described, thus suggesting the presence of a SAP totally isolated from the subarachnoid space and mimicking an intradural lesion (Bassiouni et al 2004, Jurina andGrevel 2004). This may cause minimal compliance of the fluid-filled cystic structure and persistent spinal cord compression that might explain the dilatation and severity of the lesions (Gnirs et al 2003, Wang et al 2003, Bassiouni et al 2004).…”

“…Even in those cases, in which a persistent spinal cord deformity was witnessed upon spinal surgery, subsequent clinical improvement, following the decompression, may indicate that lesions are usually mild to moderate and reversible (Frykman 1999, Gnirs et al 2003. Histopathologic analysis on SAP tissue obtained at surgery has revealed chronic mesenchymal tissue proliferation, moderate fibrosis and adhesion of pia to arachnoid mater (Gnirs et al 2003, Jurina andGrevel 2004). Degenerative changes observed in the spinal cord of affected dogs, in which a post-mortem examination was allowed, included axonal degeneration, myelin loss, multifocal white matter cystic cavitation and moderate to severe meningeal fibrosis (Rylander et al 2002).…”

“…A functional one-way valve might have developed, allowing the inflow of cerebro spinal fluid, but blocking its outflow from the cavity and leading to progressive expansion and spinal cord compression (Summers et al 1995, Jurina andGrevel 2004).…”

“…Neurological signs are usually of mild to moderate severity, being indicative of a progressive transverse myelopathy secondary to focal spinal cord compression. Most of the clinical studies describe the diagnostic approach, surgical management and outcome of the cases, but information regarding the secondary changes within the spinal cord is very limited, probably because most animals recover after surgery (Frykman 1999, Rylander et al 2002, Skeen et al 2003, Jurina and Grevel 2004. This report presents the clinical and histopathological findings in a Rottweiler with a cervical SAP and secondary focal myelopathy.…”

“…In most of the reports there is a relative overrepresentation of Rottweilers developing single or multiple SAP in the cervical spinal cord (Rylander et al 2002, Gnirs et al 2003, Jurina and Grevel 2004. The etiology of SAP remains contro versial though congenital defects or developmental malformations and secondary changes following inflammatory or repeated traumatic insults have been suggested (Rylander et al 2002, Gnirs et al 2003, Jurina and Grevel 2004.…”