Surgical treatment of lumbosacral discospondylitis by a distraction-fusion technique

Lumbosacral discospondylitis was diagnosed in three adult dogs by radiography and the isolation of Staphylococcus aureus from the affected intervertebral space. The predominant clinical findings of severe spinal pain and marked hindlimb lameness suggested entrapment of the seventh lumbar spinal nerve roots. In addition, the presence of hindlimb ataxia, proprioceptive deficits, perineal analgesia and paresis of the tail were consistent with compression of the cauda equina. Despite medical therapy with analgesics, antibiotics and strict confinement the clinical and radiographic signs progressed. A lumbosacral distraction-fusion procedure was employed to decompress the spinal nerve roots and cauda equina and to stabilise the affected vertebrae. In all cases there was an immediate marked reduction in spinal pain and a long term resolution of clinical signs. In two cases the affected vertebrae progressively fused within four months. The third case required removal of the implants due to pin migration and breakage.     

Cervical intervertebral disc protrusion in two horses

Two horses with ataxia of all four limbs were found to have cervical intervertebral disc protrusion. Severe pelvic limb ataxia, proprioceptive deficits and spasticity were present in both horses with similar but less severe signs in the thoracic limbs. Cerebrospinal fluid analysis was within normal limits. Metrizamide myelography allowed definitive diagnosis in one case when a compression of the spinal cord was demonstrated at the level of the second intervertebral space. In the second case, an intervertebral disc protrusion between cervical vertebrae 6 and 7 was found at necropsy. Fiber degeneration with poor myelin staining characterized the spinal cords histologically.     

Myelomeningocoele and a dermoid sinus-like lesion in a French bulldog

A 2-year-old male French bulldog was presented for investigation of lumbosacral pain and hindlimb ataxia associated with urinary and fecal incontinence. Survey radiography, myelography, and computed tomography images were suggestive of a dermoid sinus with associated spina bifida. Surgical intervention led to a resolution of pain and neurological deficits. Histopathological analysis of the excised tissue was compatible with a myelomeningocoele of the 7th lumbar vertebra.     

Degenerative lumbosacral stenosis in 18 dogs

Eighteen dogs with degenerative lumbosacral stenosis were presented to the University of Queensland Small Animal Clinic (UQSAC) over a three-year period. Presenting clinical signs included lumbosacral pain (89 per cent), hindlimb paresis and proprioceptive deficits (56 per cent), lameness (49 per cent), flaccid tails (22 per cent), and urinary dysfunction (16 per cent). All 18 dogs were treated by decompressive laminectomy. Two dogs were also treated by a pin fixation-fusion technique. The major compressive lesion was a type II disc protrusion (72 per cent). Seventeen dogs (94 per cent) showed improvement postoperatively with minimal complications. Confirmation of diagnosis is difficult in that many aged dogs without clinical signs show radiographic signs compatible with stenosis.     

MAGNETIC RESONANCE IMAGING OF THE CAUDAL LUMBAR AND LUMBOSACRAL SPINE IN 13 DOGS (1990–1993)

The caudal lumbar and lumbosacral spine of 13 dogs with pain or neurologic deficits were evaluated using magnetic resonance imaging (MRI). Spin echo T1, proton density, and T2 weighted and gradient echo T2* imaging sequences were utilized. MRI permitted direct, multiplanar, tomographic visualization of the spine facilitating evaluation of all components of degenerative caudal lumbar and lumbosacral stenosis. Abnormalities detected included intervertebral disc degeneration, intervertebral disc protrusion involving both the vertebral canal and intervertebral foramina, articular process osteophytosis, articular process fracture, nerve root impingement by spondylosis deformans, and the presence of low signal material within the vertebral canal of 2 dogs with recurrent pain following previous spinal surgery. In all 7 dogs treated surgically, MRI findings were consistent with surgical findings.     

RADIOGRAPHIC, COMPUTED TOMOGRAPHIC AND HISTOPATHOLOGIC APPEARANCE OF A PRESUMED SPINAL CHORDOMA IN A DOG

A 4-year-old Labrador Retriever presented for urinary incontinence and constipation of 2 weeks duration. There was a tender abdomen, lumbar pain and conscious proprioceptive deficits in both pelvic limbs. Depressed pelvic limb reflexes were present consistent with a lower motor neuron lesion. In radiographs of the lumbar spine there was narrowing of the intervertebral disc space at L5-L6 with irregular, multifocal areas of mineralized opacities dorsal to the intervertebral disc space, presumably within the vertebral canal. On computed tomography, an intramedullary, partially mineralized mass was identified in the spinal cord at the level of caudal L5 through cranial L6. At necropsy there was a four-centimeter enlarged, irregular segment of spinal cord at the level of L5-L6. When sectioned, the spinal cord bad a mineralized texture. Histologically there were variable sized cells that were stellate in appearance with vacuolated cytoplasm (physaliferous cells) and mucinous background consistent with a chordoma. Chordoma is a rare, skeletal neoplasm that originates from mesoderm-derived notochord and has been reported in humans and animals. Extraskeletal development of a chordoma within the spinal cord is a rare manifestation of this neoplasm. However, based on other reports in dogs, solitary extraskeletal locations of chordomas may be the typical expression of this neoplasm in the dog. Differentiation of similar histologically appearing tumors, such as a parachordoma or myxoid chondrosarcoma, will require immunohistochemical characterization of these tumors in veterinary patients.     

Paravertebral malignant peripheral nerve sheath tumour (MPNST) in a horse

A 10‐year‐old Lipizzaner gelding was presented with intermittent ataxia and hindlimb weakness. Ultrasonographic examination identified a mass cranial to the tuber sacrale. A provisional diagnosis of a soft tissue sarcoma was made based on a biopsy specimen. Owing to the extensive nature of the tumour and the associated poor prognosis, the horse was subjected to euthanasia on humane grounds. A post mortem examination revealed a locally infiltrative soft mass within the left lumbosacral epaxial musculature. Histologically, an infiltrative neoplasm predominantly composed of pleomorphic spindle or stellate‐shaped cells was identified. Neoplastic cells exhibited strong S‐100 protein and GFAP expression and variable vimentin, NSE, NGFR and myoglobin expression. They were uniformly negative for pan‐cytokeratin, melan A, laminin and desmin. The ultrastructural examination revealed pleomorphic cells with long cytoplasmic processes and an absence of melanosomes. Based on these results, a diagnosis of malignant peripheral nerve sheath tumour was made. This report contributes further information to assist in the diagnosis of these poorly defined neoplasms in animals, especially when they occur in uncommon locations.     

Imaging diagnosis and clinical presentation of a Chiari malformation in a Thoroughbred foal

A newborn Thoroughbred foal was presented to the clinic with ambiguous neurological deficits, spinal anomalies and a soft tissue swelling dorsal to the lumbar vertebral column. The foal was alert but unable to rise and stand. With radiography, ultrasonography, computed tomography (CT) and magnetic resonance imaging (MRI) a lumbar dysraphic anomaly, cerebellar herniation and coincidental skeletal abnormalities were documented. Finally, a meningomyelocele was defined and, in context with the cerebellar herniation through the foramen magnum, the foal was diagnosed to have a Chiari malformation. The MRI examination corresponded best with the post mortem findings. Although 3‐dimensional imaging methods have been considered superior regarding full and detailed assessment of the congenital malformation, radiography and ultrasonography also provide essential information to diagnose dysraphic lesions at reduced costs and efforts. A Chiari malformation should be considered as a differential diagnosis in foals with neurological deficits.     

CLINICAL,IMAGING, AND PATHOLOGIC CHARACTERISTICS OF GURLTIA PARALYSANS MYELOPATHY IN DOMESTIC CATS FROM CHILE

Gurltia paralysans is a rare metastrongylid nematode of domestic cats that is found mainly in the veins of the spinal cord subarachnoid space and parenchyma. Endemic regions for G. paralysans mainly include Chile and Argentina. The ante mortem diagnosis of gurltiosis is difficult and based primarily on neurological signs, epidemiological factors, and the exclusion of other causes of feline myelopathies. The purpose of this retrospective case series was to describe clinical, imaging, and pathologic characteristics in nine domestic cats naturally infected with G. paralysans. Imaging tests included radiography, myelography, computed tomographic myelography (myelo‐CT), and magnetic resonance imaging (MRI). Neurological signs included paraparesis, paraplegia, pelvic limb ataxia and proprioceptive deficits, pelvic limb tremors, lumbosacral hyperesthesia, and tail trembling or atony. Complete blood count findings included a decrease in the mean corpuscular hemoglobin concentration value in eight cats. Eosinophilia in peripheral blood was observed in three cats, and thrombocytopenia was observed in three cats. Cerebrospinal fluid analysis revealed mononuclear pleocytosis in five cases. Myelo‐CT showed diffuse enlargement of the spinal cord at the midthoracic, lumbar, and sacral regions in all cats. Magnetic resonance image findings in the thoracic and lumbar region demonstrated multiple small nodular areas of T2 hyperintensity in the periphery of the spinal cord parenchyma. Localized intraparenchymal areas of increased T2 intensity were also observed in the thoracolumbar spinal cord and lumbosacral conus medullaris. In conclusion, G. paralysans should be considered as a differential diagnosis for domestic cats in endemic regions that have this combination of clinical and imaging characteristics.     

Equine cervical intervertebral disc degeneration is associated with location and MRI features

Morphology of the equine cervical intervertebral disc is different from that in humans and small companion animals and published imaging data are scarcely available. The objectives of this exploratory, methods comparison study were (a) to describe MRI features of macroscopically nondegenerated and degenerated intervertebral discs (b) to test associations between spinal location and macroscopic degeneration or MRI‐detected annular protrusion and between MRI‐detected annular protrusion and macroscopic degeneration, and (c) to define MRI sequences for characterizing equine cervical intervertebral disc degeneration. Ex vivo MRI of intervertebral discs was performed in 11 horses with clinical signs related to the cervical region prior to macroscopic assessment. Mixed‐effect logistic regression modeling included spinal location, MRI‐detected annular protrusion, and presence of macroscopic degeneration with “horse” as random effect. Odds ratio and 95% confidence interval were determined. Reduced signal intensity in proton density turbo SE represented intervertebral disc degeneration. Signal voids due to presence of gas and/or hemorrhage were seen in gradient echo sequences. Presence of macroscopic intervertebral disc degeneration was significantly associated with spinal location with odds being higher in the caudal (C5 to T1) versus cranial (C2 to C5) part of the cervical vertebral column. Intervertebral discs with MRI‐detected annular protrusion grades 2‐4 did have higher odds than with grade 1 to have macroscopic degeneration. It was concluded that MRI findings corresponded well with gross macroscopic data. Magnetic resonance imaging of the equine cervical intervertebral disc seems to be a promising technique, but its potential clinical value for live horses needs to be explored further in a larger and more diverse population of horses.     

Treatment of encephalomyelitis due to Neospora caninum in a litter of puppies

A case of encephalomyelitis and polyradiculoneuritis caused by the protozoan parasite Neospora caninum is described in a 17-week-old bloodhound puppy exhibiting progressive paraplegia, Exposure of the dam and litter to N caninum was confirmed by serological testing for specific antibodies. A successful treatment regimen was employed in a littermate, and in two puppies from a subsequent litter from the same dam, all showing ataxia and hindlimb proprioceptive deficits.     

Paresis secondary to an extradural hematoma in a Sumatran tiger (Panthera tigris sumatrae).

A 15-yr-old female Sumatran tiger (Panthera tigris sumatrae) was presented to the Boren Veterinary Medical Teaching Hospital at Oklahoma State University with a 3-wk history of progressive hind limb weakness. Neurologic evaluation was limited to review of videotape that demonstrated weakness and ataxia with conscious proprioceptive deficits of the tiger's pelvic limbs. Spinal radiography demonstrated disc space narrowing, and myelography demonstrated a large extradural compressive lesion at the level of L2-3. Computed tomography did not reveal bone involvement. Surgery was performed to decompress the spinal cord and obtain a definitive diagnosis. A right hemilaminectomy was performed after a dorsal approach to the lumbar spine. Histologic examination of the mass revealed a consolidated extradural spinal hematoma, presumed to be secondary to intervertebral disc herniation. Despite incomplete resection of the mass and plastic deformation of the spinal cord, the tiger returned to normal ambulation within 3 wk of surgical decompression.     

ULTRASONOGRAPHIC FINDINGS IN THE LUMBOSACRAL JOINT OF 43 HORSES WITH NO CLINICAL SIGNS OF BACK PAIN OR HINDLIMB LAMENESS

The transrectal ultrasonographic appearance of the lumbosacral joint was assessed in 43 horses with no history or clinical evidence of back pain or hindlimb lameness. In the majority of horses (34/43, 79.1%) the lumbosacral disc had uniform or mildly heterogeneous echogenicity. However, variation in the ultrasonographic appearance of the lumbosacral joint was also identified, including hyperechogenic regions within the lumbosacral disc with or without an acoustic shadow, and mild or moderate irregularity of the opposing surfaces of the last lumbar and the first sacral vertebral bodies. Marked irregularity of the bony surfaces or marked disruption of the lumbosacral disc was not seen in any horse. The mean distance between the ventral aspects of the last lumbar and first sacral vertebrae was 14.2 mm (range: 7.1–26.5 mm, median: 14.4 mm). The degree of protrusion of the ventral aspect of the lumbosacral disc ranged from 0 to 5 mm (mean: 1.32 mm, median: 1.2 mm). The mean angle between the ventral surfaces of the last lumbar and first sacral vertebrae was 147° (range: 118–165°, median: 150°). There was no significant effect of age, breed, gender, or the size of the horses on either subjective findings in the lumbosacral joint or objective measurements.     

A case of diffuse bilateral scrotal neurofibroma in a rabbit

This report details a rare case of diffuse bilateral scrotal neurofibroma complicated by hindlimb paralysis in a rabbit. The animal was evaluated for unusual bilateral scrotal enlargement. After physical examination, ultrasound scan, radiography, computed tomography and laparoscopy, surgical exploration of the scrotum was undertaken. A homogeneous rubbery firm mass was revealed in contact with the subcutaneous tissue expanding to the entire scrotum without involving the testicles. The mass was excised and diagnosed as diffuse scrotal neurofibroma based on histological and immunohistochemical findings (S‐100 antibody positive). Over the following month, progressive neurological signs (faecal incontinence, flaccid bladder and hindlimb paralysis) were observed. After excluding central nervous system infection with Encephalitozoon cuniculi, expansion of the neurofibroma to the vertebral canal causing compression of the spinal cord was suspected, although not histopathologically verified.     

MAGNETIC RESONANCE IMAGING OF PRESUMPTIVE LUMBOSACRAL DISCOSPONDYLITIS IN A DOG

A three-year-old male Boxer dog had hyperesthesia, symmetrical epaxial, gluteal and hind limb muscular atrophy and rear limb ataxia. Neurological deficits included decreased conscious proprioception of the left hind limb, decreased withdrawal and increased patellar reflexes of both hind limbs. The dog had a urinary tract infection with positive culture for Staphylococcus intermedius. On survey radiography of the lumbosacral spine there was active bone proliferation spanning the L7 S1 intervertebral disc space with an epidural filling defect at the ventral aspect of the vertebral canal on epidurography, On magnetic resonance imaging (MRI), findings were similar to those described for human diskospondylitis including altered signal intensity and nonuniform contrast enhancement of the L7-S1 intervertebral disc, adjacent vertebral end plates and epidural and sublumbar soft tissues. Although skeletal radiography is usually sufficient to reach a diagnosis of discospondylitis, MRI of this patient made it possible to reach a presumptive diagnosia of discospondyltis prior to development of definitive radiographic abnormalties.     

Spinal meningeal sarcoma in a rottweiler puppy

An 11-week-old rottweiler puppy was presented for evaluation of progressive paraparesis, urinary and faecal incontinence. Radiography and myelography revealed widening of the vertebral canal and remodelling of several lumbar vertebrae associated with an intramedullary spinal mass. Magnetic resonance imaging revealed an extensive, heterogeneous mass involving the lumbosacral spinal cord. Histopathological examination indicated a meningeal sarcoma with very varied cytological architecture.     

COMPARISON BETWEEN COMPUTED TOMOGRAPHY,FLUOROSCOPY, AND ULTRASONOGRAPHY FOR GUIDING PERCUTANEOUS INJECTION OF THE CANINE INTERVERTEBRAL DISC

A minimally invasive method for delivering injectable therapeutic agents would be desirable for the treatment of intervertebral disc disease in dogs. The purpose of this study was to compare computed tomography (CT), ultrasonography (US), and fluoroscopy modalities for guiding percutaneous injection into canine intervertebral discs. Intervertebral discs of 14 dog cadavers were injected with a gelified ethanol therapeutic agent. Successful injectate placement and injectate leakage were determined based on necropsy inspection of discs. Injection into the nucleus pulposus was successful in 55 of 78 (71%) of all injected discs. Injections guided using CT and fluoroscopy were significantly more successful than US‐guided injections. Odds of successful injection without leakage were greater for CT vs. US (P = 0.0026) but there was no significant difference between CT and fluoroscopy (P = 0.0620). Injection success rates did not differ among vertebral sites or dog cadavers of varying weights. Forty‐nine (63%) of injection sites had injectate leakage outside the disc and 10 of these involved structures within the vertebral canal. The highest rate of injection success with the least amount of leakage was achieved with CT guidance. Findings indicated that CT, fluoroscopy, and US are feasible modalities for guiding percutaneous injection of a gelified ethanol therapeutic agent into the canine intervertebral disc, with moderate to high success rates for different regions of the spine. However, a moderately high rate of injectate leakage occurred outside of the disc and this should be taken into consideration for future safety and efficacy studies.     

Review of the use of transrectal ultrasonography for evaluation of the caudal lumbar – including lumbosacral – intervertebral discs and symphyses: Normal and abnormal ultrasonographic appearance

Transrectal ultrasonography of the lumbosacroiliac area is routinely performed for the diagnosis of the cause of low back pain and poor hindlimb impulsion and engagement. The ventral aspect of the caudal lumbar intervertebral discs and vertebrae can be easily assessed transrectally with ultrasound while other imaging modalities have limitations for diagnosis of intervertebral disc injuries. This paper is a review of the ultrasonographic procedure for imaging the ventral aspect of the caudal lumbar and lumbosacral symphyses, especially the intervertebral discs. Normal images, findings and lesions of the three caudalmost lumbar intervertebral discs are described (between the 4th lumbar and the 1st sacral vertebrae).     

Equine intervertebral disk disease: A case report

Intervertebral disk disease is common in humans and dogs but is rarely reported in horses. In this case report, we describe an 11-year-old American Saddlebred gelding with a 2-month history of pain and progressive neurological abnormalities (ataxia, conscious proprioceptive deficits involving all four limbs, toe dragging, and restricted neck flexion) while being worked as a Saddleseat show horse. Radiographs of the cervical spine showed a loss of the intervertebral disk space at C₆–C₇. At necropsy, nearly complete loss of the intervertebral disk at C₆–C₇ was seen, with marked eburnation and subchondral sclerosis of the adjacent vertebral endplates that were confirmed by histopathology. Many of the marrow spaces of the affected vertebral bodies were filled with cartilage and others contained variable amounts of fibrous connective tissue (myelofibrosis). To our knowledge, these pathological lesions are rarely reported in the literature and appear to represent a chronic, end-stage phase of cervical vertebral stenosis.