Compressive Myelopathy Associated With Ectasia of the Vertebral and Spinal Arteries in a Dog

Abstract

A 4-year-old dog was presented for acute, progressive tetraparesis and cervical hyperesthesia. Symmetrical tubular structures coursing along the lateroventral aspects of the spinal cord at the fourth and fifth cervical vertebrae were identified in magnetic resonance images. At necropsy, vertebral arteries and their spinal branches were severely ectatic bilaterally, and the cervical spinal cord was compressed. Histologically, the ectatic branches of the vertebral and ventral spinal arteries were surrounded by fibrosis with scant mononuclear cell infiltrates and hemorrhage. Spinal branches of the vertebral arteries had focally severe reduction in the tunica media. A thrombus was in an arterial branch. Smaller vessels in adjacent tissue had fibrinoid degeneration. Axonal degeneration was detected in the affected spinal cord and nerve roots. The segmental degenerative radiculomyelopathy in this dog was attributed to anomalous ectasia of the vertebral and ventral spinal arteries.Keywords axonal degeneration, cardiovascular system, dog, nervous system, radiculomyelopathy, spinal cord, vascular ectasia A 4-year-old neutered male crossbred Catahoula Leopard dog was referred to the Veterinary Medical Teaching Hospital, University of Missouri, for acutely progressive, nonambulatory tetraparesis and severe cervical hyperesthesia of 48 hours' duration. A functional deficit was localized to the C6-T2 segments of the spinal cord by neurologic examination. Markedly enlarged intervertebral foramina at C4-5 and C5-6 were identified in radiographs. The dorsal and middle portions of the C4 and C5 vertebral bodies were irregularly shaped and sclerotic. In magnetic resonance images (transverse and sagittal T1-and T2-weighted sequences), bilaterally symmetrical hypointense tubular structures coursed along the lateroventral aspects of the C4 and C5 spinal cord segments (Figs. 1, 2), compressing the ventral aspect of the spinal cord and effacing the dorsal aspect of the C4 and C5 vertebral bodies. The tubular structures communicated with a large vessel extending from the thorax. A vascular anomaly was suspected with secondary spinal cord compression and vertebral erosion. Based on the imaging results, severity of clinical signs, and rapid deterioration of the patient, the prognosis was deemed poor, and the dog was humanely euthanized. Pathologic FindingsGrossly, severely ectatic right and left vertebral arteries entered the vertebral column lateroventrally at C6 (Figs. 3, 4). The ectasia resulted in saccular arterial dilations up to 5.2 cm long and 1.2 cm in external diameter. A probe was easily inserted in both vessels and could be extended cranially to the C4 region. The spinal canal was enlarged from C4 to C6, and the spinal branches of the vertebral arteries at this site were tortuous and ectatic, up to 5 mm in diameter (Figs. 3, 5). The ventral spinal artery (in formalin-fixed C4-to-C5 spinal cord) was ectatic, ranging from 2 to 3 mm in diameter, whereas the artery was 0.4 to 0.6 mm in diameter in unaffected areas of the s...

Bilateral Vertebral Venous Sinus Thrombosis Causing Cervical Spinal Cord Compression in a Dog

“…Vertebral venous thrombosis appears even more rare, with no reports in the veterinary literature and the reports published in the human literature are only vaguely similar to the case reported herein ( 8 – 12 ). Vertebral artery thrombosis, vertebral artery aneurysm, and vertebral arteriovenous malformation with thrombosis have been associated with neurologic dysfunction in human patients ( 8 – 10 ), and chronic myelopathy with concurrent vertebral and spinal artery thromboses in a dog has also been reported ( 13 ). Enlargement of the vertebral sinuses have also been associated with neurologic dysfunction and spinal cord compression in human patients ( 8 ).…”

“…Vascular malformations ( 10 , 12 ), iliac or vena caval thrombosis ( 10 , 12 ), spinal cord compression ( 10 ), intracranial hypotension ( 12 ), and portal hypertension ( 12 ) have been identified as risk factors for epidural venous enlargement. In the veterinary literature, vertebral venous thrombosis has not been reported, though there are sparse case reports of central nervous thromboses associated with meningeal infection ( 14 ), head trauma ( 14 ), a potential genetic predisposition ( 13 ), or idiopathic CVT ( 14 ).…”

Arterial Blood Supply to the Spinal Cord in Animal Models of Spinal Cord Injury. A Review

“…In the study of SCI, several species of experimental animals, for example, pigs (Jones et al, ; Lee et al, ; Šulla et al, ), dogs (Fujimaki et al, ; Bozynski et al, ; Sarmento et al, ), cats (Tsitsopoulos et al, ; Gu et al, ; Murphy et al, ), rabbits (Fang et al, ; Leonard et al, ; Mechírová et al, ), guinea pigs (Ouyang et al, ; Galle et al, ; Sun et al, ), rats (Chung et al, ; Losey and Anthony, ; Soubeyrand et al, ), and mice (Abematsu et al, ; Awad et al, ; Gaviria et al, 2012) are used.…”

Myelopathy secondary to an intramedullary arteriovenous malformation in a mature dog

“…Vascular malformations affecting the spinal cord are rare in veterinary medicine, with only a few case reports in the literature. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] In human medicine, the most widely accepted classification system divides vascular malformations of the central nervous system into 4 groups according to their histopathological features (Table 1): (a) capillary telangiectasia, (b) cavernous malformation, (c) venous angioma, and (d) AVM. 17,18 Arteriovenous malformations are congenital abnormalities of the vasculature, in which a connection between the arterial and venous systems exists without an intervening capillary bed.…”