Compressive Myelopathy due to Intervertebral Disk Extrusion in a Llama (Lama Glama)

Abstract

Abstract.A 12-year-old intact female llama was euthanized following acute onset of spastic tetraparesis and recumbency with inability to rise. Postmortem examination revealed caudal cervical spinal cord compression due to a mass within the ventral spinal canal arising from the C6-C7 intervertebral disk space and attached to an irregularly thickened annulus fibrosis. On histopathologic examination, the mass was composed of amorphous acellular basophilic to amphophilic material admixed with irregularly arranged collagen bundles. The amorphous material was metachromatic and contained multiple small foci of markedly vacuolated round cells, characteristic of origin from the nucleus pulposus. Severe necrosis of all white matter tracts with astrocytic reaction was present in the overlying spinal cord segment. Ascending and descending Wallerian degeneration and dissecting interstitial astrogliosis were present within white matter tracts above and below the lesion, respectively. The diagnosis was compressive myelopathy due to chronic extrusion of the nucleus pulposus of the C6-C7 intervertebral disk. To the authors' knowledge, this is the first report of intervertebral disk disease in a camelid.

MRI evaluation of spontaneous intervertebral disc degeneration in the alpaca cervical spine

“…The present work identified features on MR images of the lower alpaca cervical spine that indicate that alpacas may experience cervical disc degeneration at high enough rates that make alpacas potentially feasible for evaluating treatments of DDD in humans. Similar to humans, the present work demonstrates that increasing age was correlated with a higher likelihood of DDD and that progression of DDD in aging camelids may be similar to the human condition in regards to prevalence and severity . This, and other parallels that were identified in this study in regards to age and location of degeneration, strengthens the case to further investigate alpacas and other members of the camelid family (e.g., llama) to better understand the strengths and limitations of this potential large animal model of disc degeneration in regards to types and mechanism of degeneration.…”

Biomechanical analysis of the camelid cervical intervertebral disc

“…Painful degenerative disc disease was first documented in llamas in 2006 [18] , and prompted our interest in investigating biomechanical and anatomical similarities between camelid and human spines, with the aim of determining the appropriateness of using camelids (specifically llamas and alpacas) as preclinical models for spine treatments. We aim to address key characteristics of a good animal model for the human IVD, including biomechanical flexibility testing, and disc morphology (shape and size) [18] . The purpose of this paper is to report on our findings for the camelid cervical IVD in the context of providing an animal model of the human lumbar IVD.…”

Dysuria due to discospondylitis and intervertebral disc herniation in a male alpaca (Vicugna pacos)

“…Reports of neurological disease in new world camelids are limited [ 7 ]. However, ataxia and paresis in llamas and alpacas have been described due to systemic infectious diseases (e.g., equine herpes virus 1 infection, listeriosis), local bacterial infections with discospondylitis, parasite-induced leucomyelopathy, degenerative myeloencephalopathy, or intervertebral disc protrusion [ 1 , 7 – 10 ].…”

“…Reports of neurological disease in new world camelids are limited [ 7 ]. However, ataxia and paresis in llamas and alpacas have been described due to systemic infectious diseases (e.g., equine herpes virus 1 infection, listeriosis), local bacterial infections with discospondylitis, parasite-induced leucomyelopathy, degenerative myeloencephalopathy, or intervertebral disc protrusion [ 1 , 7 – 10 ]. In general, discospondylitis seems to be a rather rare disease in new world camelids, with clinical signs similar to those seen in other species but displaying huge variability [ 9 , 11 – 16 ].…”