A SACRAL LESION RESEMBLING OSTEOCHONDROSIS IN THE GERMAN SHEPHERD DOG

More than 30% (21 of 65) of German Shepherd dogs with clinical signs of cauda equina compression had radiographic and pathologic abnormalities compatible with osteochondrosis of the sacral endplate. Most of these dogs had a defect in the dorsal part of the sacral endplate and a detached bone fragment in the vertebral canal. Similar lesions were also found in growing and young adult dogs without clinical signs. The dogs with clinical signs of cauda equina compression also had severe degenerative disc disease with protrusion of the lumbosacral disc and compression of the cauda equina, suggesting that the signs of cauda equina compression more likely were related to the secondary degenerative changes (disc protrusions) rather than the primary disease. Clinically normal German Shepherds with sacral osteochondrosis usually were younger than 18 months, the dogs with cauda equina compression and sacral osteochondrosis older than 18 months (mean age 4.8 years). On the average, these dogs were two years younger as compared to dogs with cauda equina compression without sacral osteochondrosis. Male dogs are more often affected than females (5:1). There is a breed predisposition: in dogs other than German Shepherds, osteochondrosis of the sacral endplate seems to be extremely rare.     

Synovial cysts associated with cauda equina syndrome in two dogs

OBJECTIVE: To report synovial cysts associated with cauda equina syndrome in 2 dogs. STUDY DESIGN: Clinical cases. ANIMALS: Two German Shepherd dogs. METHODS: After magnetic resonance imaging detection, cysts were surgically removed via dorsal laminectomy. RESULTS: Six and 8 months after surgery, both dogs were free of clinical signs and no pain was elicited on lumbosacral joint manipulation. CONCLUSION: Although described in dogs, cysts at the lumbosacral joint might cause compression of the cauda equina nerve roots. Radical excision of the cyst capsule can result in resolution of clinical signs. CLINICAL RELEVANCE: Synovial cysts should be considered in the differential diagnosis of dogs with cauda equina compression syndrome when lumbosacral degenerative joint disease is present.     

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.     

Radiculomeningomyelitis due to Halicephalobus gingivalis in a horse

An adult horse was euthanatized following a clinical diagnosis of cauda equina neuritis. Significant gross postmortem and histopathologic findings were limited to the sacral spinal cord and cauda equina. The sacral spinal cord, meninges, and spinal nerve roots were expanded and partially effaced by sclerosing granulomatous inflammation with necrosis. The lesion contained numerous nematode larvae and fewer adults with a rhabditiform esophagus having a corpus, isthmus, and valved bulb. Female nematodes were amphidelphic and didelphic with reflexed ovaries. These morphologic features confirm Halicephalobus gingivalis as a novel cause of clinical signs in this case of cauda equina neuritis.     

Lumbosacral stenosis and injury of the cauda equina

Idiopathic (congenital) L/S stenosis, acquired (degenerative) L/S stenosis, and traumatic injury to the vertebral column caudal to L6 often produce signs of neurologic dysfunction attributed to compression, displacement, entrapment, or trauma of the cauda equina. Clinical signs vary from animal to animal and depend upon which roots of the cauda equina are involved and the nature of the compromise. An understanding of the anatomy of the area and an appreciation for the functional relationship between the cauda equina and structures innervated are essential for accurate evaluation, workup, diagnosis, treatment, and outcome.     

Diagnosis of Cauda Equina Abnormalities By Using Electromyography, Discography, and Epidurography in Dogs

Electromyography (EMG), L7-S1 discography and epidurography were investigated in 15 dogs with clinical signs of cauda equina dysfunction and in 7 control dogs without such clinical signs. Electromyography of paraspinal and pelvic limb muscles was done in 13 of 15 affected dogs. An L7-S1 discogram followed by an epidurogram was performed in all 22 dogs using 20% iopamidol. Results of discograms, epidurograms, and gross necropsy examinations were normal in six of seven control dogs. The one dog in which these studies were abnormal had a mild L7-S1 disc protrusion that did not result in nerve root compression at necropsy. Electromyographic analysis was 100% accurate in predicting the presence or absence of cauda equina disease. None of the results of discograms were falsely negative. Twelve of 15 discograms in clinically affected dogs indicated dorsal disc protrusion, but 2 of these protrusions were found to be noncompressive at surgery (13% error). Abnormal epidurograms occurred in 9 of 15 clinically affected dogs. There was one false positive and two false negatives (20% error). Electromyography was a sensitive screening technique for the presence of cauda equina disease. Discography may be more sensitive for detection of L7-S1 disc protrusion than epidurography. An abnormal radiographic contrast study of the cauda equina may only be useful when combined with an abnormal EMG.     

Intramedullary Spinal Glioblastoma in a Cat, Presented as a Cauda equina Syndrome

A ten year old castrated male domestic short haired cat, was presented with clinical signs related to the cauda equina. The results of the neurological examination, diagnostic procedures, and clinical course are presented. At necropsy a glioblastoma of the caudal spinal cord was present. The difficulties in distinguishing between neoplasms arising in the cauda equina and the caudal spinal cord are discussed. A comparative discussion of the cauda equina syndrome is presented.     

X-ray studies of the cauda equina of dogs

This article reviews the radiologic examination of the canine cauda equina. The radiographic technique and interpretation of survey radiographs, radiographs with the spine in flexion and extension, tomography and contrast procedures, the diagnostic value and limits of these methods are discussed. The diseases which may cause cauda equina compression and the radiographic findings are described and illustrated.     

Transitional lumbosacral vertebral anomaly in the dog: a radiographic study

Transitional lumbosacral vertebral anomalies have for some time been suggested as a possible cause of cauda equina syndrome (especially in the German shepherd dog [GSD]), a condition recently thought to be inherited. The frequency of this condition within a large clinical population and the radiographic features used in its detection are reported. In a group of 143 patients, the sexes were similarly represented and the GSD was greatly overrepresented. The anomaly is characterised by separation of the first sacral segment that was identified on the lateral view by the presence of a radiolucent disc space between what are normally the first and second sacral segments. On the ventrodorsal view, the anomaly was characterised by separation of the spinous processes between what are normally the first and second sacral segments. In the presence of the transitional segment, the nature of the sacroiliac joint at the level of the anomalous segment varies from a strong ilial attachment, with the presence of a wing-like lateral process, to a weakened ilial attachment because of the presence of a lateral process, shaped as that seen on a lumbar segment. These patterns were present unilaterally or bilaterally and result in symmetrical or asymmetrical patterns. The effect of the weakening of the sacroiliac attachment was thought to result in premature disc degeneration, which, together with spinal canal stenosis, resulted in potential compression of the overlying spinal nerves and creation of a cauda equina syndrome. The condition is thought to have clinical significance and should be selected against in breeding, especially in the GSD.     

COMPARISON BETWEEN COMPUTED TOMOGRAPHIC AND SURGICAL FINDINGS IN NINE LARGE-BREED DOGS WITH LUMBOSACRAL STENOSIS

In a three-year prospective study, computed tomographic (CT) and surgical findings were compared for nine large breed dogs with lumbosacral stenosis. Surgically-excised tissue was examined histologically in seven dogs and additional necropsy evaluation was performed in one dog. The CT abnormalities observed at sites of confirmed cauda equina compression were: loss of epidural fat, increased soft tissue opacity, bulging of the intervertebral disc margin, spondylosis, thecal sac displacement, narrowed intervertebral foramen, narrowed vertebral canal, thickened articular process, articular process subluxation, articular process osteophyte, and telescoped sacral lamina. The CT characteristics of lumbosacral degenerative disease and discospondylitis were similar to those described in humans. In three dogs, CT findings at the site of cauda equina compression were consistent with congenital or developmental spinal stenosis, but the method of surgical exposure precluded confirmation. Epidural fibrosis (eight dogs) and multi-level CT abnormalities (six dogs) were identified but the cause(s) and significance were unknown.     

FLEXION-EXTENSION MYELOGRAPHY OF THE CANINE CAUDA EQUINA

The radiographic appearance of the canine dural end-sac and its behavior during flexion and extension of the spine is described in a myelographic study in 22 normal dogs and 26 dogs with cauda equina compression syndrome. In more than 80% of the dogs, the dural sac ended at the level of the sacrum. There were relatively large individual differences in shape and size of the dural end-sac. In contrast, shape, length, position, and diameter of the dural end-sac at the level of the lumbosacral articulation is extremely constant during flexion and extension in normal individuals. In the 26 dogs with lesions affecting the cauda equina and nerve roots between L6 and the first caudal vertebra, myelography was diagnostic in 21 dogs. Myelographic diagnosis of cauda equina compression was possible in seven dogs with spine in flexion. In 14 dogs, overextension of the spine and imaging in lateral and dorsal recumbency was necessary to establish a diagnosis. The five dogs with nondiagnostic myelograms had either a dural end-sac ending cranially to the lesion (two dogs), diseases not associated with compression (two dogs), or only slight indentations of the contrast medium column (one dog).     

Prevalence of radiographic signs of degenerative joint disease in a hospital population of cats

The prevalence of radiographic signs of degenerative joint disease (including appendicular osteoarthritis) among a hospital population of 218 cats was 33.9 per cent (74 cats), and the prevalence of signs of appendicular joint osteoarthritis was 16.5 per cent (36 cats). Half of the cases of appendicular joint osteoarthritis had no apparent radiographic or historical cause, and clinical signs of lameness were recorded in only six of them, all of which had an apparent radiographic cause. The 74 cats with radiographic signs of degenerative joint disease were on average significantly older than the 144 cats in which there were no radiographic signs of the disease.     

Radiographic evidence of degenerative joint disease in geriatric cats: 100 cases (1994-1997)

OBJECTIVE: To determine prevalence of radiographic evidence of degenerative joint disease (DJD) in geriatric cats. DESIGN: Retrospective study. POPULATION: 100 cats > 12 years of age. PROCEDURE: One investigator reviewed radiographs and for each articulation (or group of articulations) that was visible assigned a grade of severity (0, 1, 2, 3) for DJD. Another investigator reviewed medical records and recorded signalment, environment, previous disease, diseases evident at time of radiography, FeLV vaccination and infection status, feline immunodeficiency virus serologic status, serum creatinine concentration, serum globulin concentration, and any other important findings. Associations between DJD of grade 2 or 3 and variables recorded from the medical record were determined. RESULTS: Radiographic evidence of DJD was evident in 90% of cats. Neurologic disease was associated with lesions in the lumbosacral portion of the vertebral column. Severe lesions were found in 17% of the elbow joints, but an underlying cause was not determined. CONCLUSIONS AND CLINICAL RELEVANCE: Degenerative joint disease was detected radiographically in most geriatric cats and may be an overlooked cause of clinical disease. Clinicians should be alert to the possibility that DJD is associated with neurologic signs.     

DISCOGRAPHY AND EPIDUROGRAPHY FOR EVALUATION OF THE LUMBOSACRAL JUNCTION IN DOGS WITH CAUDA EQUINA SYNDROME

Cauda equina syndrome in the dog is a common neurologic disorder caused by compression of the spinal cord, nerve roots and spinal nerves caudal to the fifth lumbar vertebra. This paper describes the clinical signs, radiographic findings of discography and/or epidurography, and comparison with surgery or necropsy of 21 dogs with cauda equina syndrome. Discograms were performed by using a 20- or 22-gauge spinal needle introduced in a sagittal plane into the lumbosacral (LS) disc space under fluoroscopic guidance. Epidurograms were performed following discography by injecting contrast medium after repositioning the tip of the needle into the ventral epidural space at the level of the LS junction. Direct examination of the LS junction was performed in all dogs by surgical exploration and/or necropsy. On survey radiographs, the most common findings were spondylosis, malalignment of the sacrum to the last lumbar vertebra, collapse of the LS disc space, stenosis of the vertebral canal at the LS junction, and transitional vertebral segments. Discography was considered of diagnostic quality in 19/21 (90%) of the dogs, showing disc protrusion in 14/21 (67%). Epidurography was of diagnostic quality in 18/18 (100%) dogs, showing abnormal findings in 14/18 (78%). No adverse reaction was noted to the radiographic procedure when dogs were allowed to recover from anesthesia before surgery. Based on macroscopic findings, combination of survey radiographs and disco-epidurography was correctly positive in 16/18 dogs (89%). It is concluded that discography associated with epidurography is a valuable procedure for evaluation of the LS junction in the dog. A combination of both procedures reduces the possibility of technical artifacts by outlining both sides of the compressive lesion, i.e., the disc and the epidural space.     

Somatosensory evoked potentials produced by stimulation of the dorsomedial nerves innervating the tail in dogs

To record the somatosensory evoked potentials (SEPs) produced by stimulation of tail nerves and determine the effects of acute compression of the cauda equina on SEPs. The subjects were 10 adult Beagles. SEPs were recorded after stimulating the dorsomedial nerves (DMN) innervating the tail. The cauda equina was compressed using a balloon catheter inserted into the vertebral arch. In SEPs, two negative and one positive peak were often observed. The compression of the cauda equina caused significant depression of the positive component. The SEPs produced by stimulation of the DMN reflect the activities of ascending neuronal pathways above the coccygeal spinal segments and may be a useful tool for examining cauda equina syndrome.     

Magnetic Resonance Imaging in the Diagnosis of Degenerative Lumbosacral Stenosis in Four Dogs

Magnetic resonance imaging was used to diagnose degenerative lumbosacral stenosis in four dogs that had physical and neurologic signs consistent with a cauda equina lesion. Nerve root displacement by protruding disc material and loss of epidural fat were identified. In all dogs, the diagnosis was confirmed by dorsal laminectomy of the lumbosacral area.     

Laminectomy for treatment of cauda equina syndrome in a cat

A 16-year-old spayed female Siamese cat was presented with a history of paraparesis and obstipation. The cat's impaired function was attributed to malalignment of the L7-S1 spine (cauda equina syndrome) and to traumatic fracture of the left femoral neck, with severe degenerative arthritis. Laminectomy resolved the cauda equina problem, and the hip joint was not treated.     

Magnetic resonance imaging in the diagnosis and surgical management of sacral osteochondrosis in a mastiff dog

The clinical, radiographic, magnetic resonance imaging (MRI), surgical and pathological findings related to an osteochondral lesion of the sacrum in a mastiff dog are described. The dog showed chronic signs of pain in its pelvic limbs. Radiography revealed a triangular mineralised opacity at the craniodorsal aspect of the sacrum consistent with sacral osteochondrosis. A T2-weighted spin-echo MRI revealed dorsal and lateral compression of the cauda equina. The osteochondral fragment was removed via a dorsal laminectomy, and the clinical signs resolved. Histological abnormalities in the fragment were consistent with a diagnosis of osteochondrosis.     

Degenerative spinal disease in large felids.

Degenerative spinal disorders, including intervertebral disc disease and spondylosis, seldom occur in domestic cats. In contrast, a retrospective study of 13 lions (Panthera leo), 16 tigers (Panthera tigris), 4 leopards (Panthera pardis), 1 snow leopard (Panthera uncia), and 3 jaguars (Panthera onca) from the Knoxville Zoo that died or were euthanatized from 1976 to 1996 indicated that degenerative spinal disease is an important problem in large nondomestic felids. The medical record, radiographic data, and the necropsy report of each animal were examined for evidence of intervertebral disc disease or spondylosis. Eight (three lions, four tigers, and one leopard) animals were diagnosed with degenerative spinal disease. Clinical signs included progressively decreased activity, moderate to severe rear limb muscle atrophy, chronic intermittent rear limb paresis, and ataxia. The age at onset of clinical signs was 10-19 yr (median = 18 yr). Radiographic evaluation of the spinal column was useful in assessing the severity of spinal lesions, and results were correlated with necropsy findings. Lesions were frequently multifocal, included intervertebral disc mineralization or herniation with collapsed intervertebral disc spaces, and were most common in the lumbar area but also involved cervical and thoracic vertebrae. Marked spondylosis was present in the cats with intervertebral disc disease, presumably subsequent to vertebral instability. Six of the animals' spinal cords were examined histologically, and five had acute or chronic damage to the spinal cord secondary to disc protrusion. Spinal disease should be suspected in geriatric large felids with decreased appetite or activity. Radiographic evaluation of the spinal column is the most useful method to assess the type and severity of spinal lesions.     

Approach to the patient with spinal disease.

The approach to the patient suspected of having spinal disease should be methodical to assure an accurate diagnosis that is cost-effective with minimal risk to the patient. Using a problem-oriented approach will facilitate attaining this goal. A neurologic examination should enable the veterinarian to localize to one of four spinal cord segments or the cauda equina.