Cardiac dysrhythmias during anesthesia for cervical decompression in the dog

In a retrospective study, the risk for cardiac dysrhythmias was evaluated in dogs undergoing ventral decompression and/or fenestration of the cervical spine (CERV) and compared with that for dogs undergoing dorsal laminectomy for decompression of the thoracic or lumbar spine (TL). The dogs in the CERV subset (48 dogs) tended to be heavier and older than the dogs in the TL subset (111 dogs). There was no apparent bias detected in treatment before anesthesia and surgery. The risk for dysrhythmias was 2.5 times greater in the CERV subset, compared with that in the TL subset (P less than 0.01). The risk for ventricular premature contraction was 3.5 times higher in the CERV group (P less than 0.05). Bradycardia was found in 6 dogs from the CERV subset and was not found in any dogs from the TL subset. A logistic model was derived from the data and may be used to evaluate the risk for dysrhythmias in similar patients undergoing similar surgery and anesthesia. This model uses age, preoperative heart rate, and site of surgery (CERV or TL) to estimate the risk.

Bacteremia and septic arthritis in a West African dwarf crocodile

An anorectic, adult West African dwarf crocodile was examined because of bilateral hind limb paresis. Clinical findings included multiple skin wounds, osteomyelitis of the distal portions of the right radius and ulna, severe anemia, and Serratia marcescens bacteremia. The crocodile died after a blood transfusion. At necropsy, hemorrhage in the subarachnoid space, suppurative polyarthritis, and gastric ulceration were found. Serratia marcescens and Morganella morganii were isolated from multiple tissues and body fluids. It was concluded that the bilateral paresis was caused by severe septic arthritis secondary to bacteremia, and that the crocodile died from spinal injury caused by the blood transfusion into the supravertebral vein.

Disc-associated wobbler syndrome in the Doberman pinscher

Disc-associated wobbler syndrome is a subset of the diverse canine wobbler complex. Disc-associated wobbler disease can occur in many large-breed dogs but the vast majority are middle-aged Doberman Pinschers. Dorsal annulus hypertrophy and protrusion is the hallmark lesion with variable association of dorsal ligamentum flavum hypertrophy and bony malformations. Chronic caudal cervical spinal cord compression results in the clinical signs. Instability, primary disc degeneration, and conformational etiologies have been incriminated. The clinical course usually entails chronic progressive paraparesis to tetraparesis with insidious onset. Acute onset or exacerbations are less common. Diagnosis is based upon history, neurologic examination, and radiography/myelography. Long-term conservative therapy is only palliative and usually leads to the demise of the animal. Surgical therapy offers the potential of a cure but at significant risk of morbidity and mortality. Surgical treatment consists primarily of decompressive techniques with or without stabilization. The numerous surgical techniques utilized highlight the variability of the lesions and the lack of universal acceptance of any one technique. Decompression is accomplished by surgical access to the vertebral canal to physically remove the abnormal ligament and/or bony material. Alternatively, distraction combined with fusion of the vertebrae adjacent to the offending disc may reduce the hypertrophied/prolapsed dorsal annulus. Regardless of the procedure, postoperative management may be fraught with complications that require special considerations.

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.

Spinal-evoked potentials in dogs with acute compressive thoracolumbar spinal cord disease

Spinal evoked potentials (SpEP) were recorded on an electromyograph from electrodes placed percutaneously in the ligamentum flava at the lumbosacral junction and between the 10th and 11th thoracic vertebrae following tibial nerve stimulation in 31 anesthetized dogs with acute compressive spinal cord injuries. The neurologic status of each dog was determined by clinical examination before SpEP recordings, and the neurologic status was monitored for 2 months in dogs that had surgical or conservative treatment. Two months after spinal injury, the response to treatment (outcome) of each dog was evaluated and graded as favorable (ambulatory and urinary continent) or unfavorable (nonambulatory, urinary incontinent, or euthanatized with confirmation of myelomalacia). Onset latencies, conduction velocities, amplitudes and durations of the wave forms, and the ratio of conduction velocity to combined durations of the first positive (P1) and first negative (N1) waves (CV/DPN index) were determined and were compared with reference data from clinically normal (control) dogs. Single SpEP recordings were of value in determining the prognosis for recovery. Significant differences were not found in the L7-S1 recordings between the reference (control) and spinal injury groups. Analysis of data from the T10-11 recordings indicated significant differences between the reference and spinal injury groups and between the favorable and unfavorable outcome groups within the spinal injury group. A CV/DPN index was less than 30 in dogs with unfavorable outcomes and greater than 30 in dogs with favorable outcomes. Stepwise discriminant analysis of data from the spinal injury group predicted outcome correctly in all dogs.

Cervical dorsal spondylosis with spinal cord compression in a black swan (Cygnus atratus)

Cervical dorsal spondylosis with spinal cord compression in a black swan (Cygnus atratus) was confirmed radiographically and morphologically. Clinically ataxia was associated. Noninflammatory, degenerative changes of the synovial joint cartilage were associated with the spondylosis.

Vertebral fracture, extensor hypertonia of thoracic limbs, and paralysis of pelvic limbs (Schiff-Sherrington syndrome) in an Arabian foal

An Arabian foal, which was recumbent for 4 days, had signs of extensor rigidity of the thoracic limbs and hypotonic paralysis of the pelvic limbs. Survey radiography revealed a lesion at T15, with radiographic impression of a compression fracture or a hemivertebra. Postmortem examination revealed a fracture at T15. Clinical and pathologic findings in this case were compatible with the Schiff-Sherrington syndrome, which is characterized by thoracic limb extensor hypertonia associated with paraplegia from acute thoracolumbar trauma.

Paralysis due to a glomangioma in a Macaca mulatta

A glomangioma at the 6-7 thoracic intervertebral space caused compression of the spinal cord with posterior paralysis in an irradiated 20-year-old female rhesus monkey (Macaca mulatta). Glomangiomas are tumors of arterial-venous shunts, are rare and have only been reported in irradiated rhesus monkeys.

Postoperative complication of cervical fracture repair in a dog

Fracture and luxation of the second cervical vertebra of a dog were repaired with braided polyester sutures. After 28 months, the dog became ataxic. Compression of the spinal cord at C1-2 was seen on a myelogram. Surgical exploration of the area revealed a granuloma associated with the sutures and compressing the spinal cord. After the granuloma was removed, the dog recovered and has remained neurologically normal for 21 months. The abnormal tissue was determined histologically to be a pyogranuloma.

Osteochondrotic changes in the vertebrae of four ataxic horses suffering from cervical vertebral malformation

Ataxia caused by a focal compression of the cervical spinal cord was diagnosed in four young standardbred trotting horses. Diagnosis was verified by myelography. Changes in the cervical vertebral column were studied using microradiographic and histologic methods. In the vertebrae involved, there was irregularity of the cartilaginous growth zone, cracks with a loose fragment and disturbance in the enchondral ossification. These changes resemble osteochondrosis. Porous appearance in lateral and ventral funiculi as well as mural calcified plaques in the small vessels of the white matter were found in the spinal cord.

Cytology of equine cerebrospinal fluid

The cytology of cerebrospinal fluid samples from horses is described. The samples were obtained from 24 normal horses, 35 horses with axonal degeneration and/or spinal cord compression, 29 horses with encephalomyelitis, 14 horses with other lesions of the nervous system, and eight horses with signs of neurologic dysfunction of undetermined origin. (Three of the latter were suspected botulinum intoxications.) Fluid was aspirated from the atlanto-occipital space following general anesthesia or immediately after a lethal dose of barbiturate. In two horses, fluid also was aspirated from the lumbosacral space. Small mononuclear cells were predominant in normal horses, and in most horses with axonal degeneration and encephalomyelitis. Several horses with encephalomyelitis also had neutrophils, eosinophils, and some mitotic figures. Although the cytologic findings were abnormal in many of the horses with disease of the central nervous system, in most horses the cytologic findings were normal.

Spinal cord compression and hindlimb paresis in cats with mucopolysaccharidosis VI

Six cats with mucopolysaccharidosis VI had hindlimb paresis and other clinical signs associated with compression of the thoracolumbar spinal cord. In 5 cats, the neurologic abnormality progressed over 2 to 4 weeks to loss of thoracolumbar spinal cord function. In 1 cat, the hindlimb paresis remained stable for 18 months. In the cats with progressive worsening of hindlimb function, the abnormality was caused by compression of the spinal cord from proliferation of bony tissue in the thoracolumbar region. In all affected cats, the compression occurred from T12 to L2. In 1 cat, an attempt to relieve the clinical signs by surgery was unsuccessful.

Neurologic diseases associated with lymphosarcoma in ten dogs

Lymphosarcoma was diagnosed in 10 dogs with initial signs referable to the nervous system. Six dogs had signs of spinal cord disease, 2 had signs of peripheral nerve disease, and 2 had signs of cranial disease. The diagnosis of lymphosarcoma involving ther nervous system was made prior to the death of each dog, and necropsy confirmed the clinical diagnosis in each case. The clinical diagnosis was based on the results of blood analysis, bone marrow examination, lymph node cytology, cerebrospinal fluid evaluation, and tumor biopsy.

Atlanto-axial malarticulation in Angora goats

Two male Angora goats presented with ataxia and weakness of the hind limbs. Both tired easily when exercised and often stumbled and fell. In both cases, post-mortem examination revealed focal areas of gliosis and diffuse Wallerian degeneration in the spinal cord at the level of the atlanto-axial joint. There were also two areas of myelomalacia in one of the goats. In the other, the caudal articular surfaces of the atlas were unusually convex and the odontoid process of the axis was laterally compressed. It is suggested that these vertebral anomalies resulted in excessive mobility of the joint leading to the development of a compressive myelopathy.

Dynamic compression of the cervical spinal cord

The authors report the radiographic and pathologic findings in 10 Great Dane dogs with the wobbler syndrome. In all 10 dogs it was possible to demonstrate myelographically that there was cervical spinal cord compression at 1 or 2 sites. The spinal cord compression was mainly dynamic in nature, as degree of compression increased in extension and decreased in flexion of the neck in 8 dogs. In 1 dog with deformed vertebral bodies (G6 and C7), compression increased slightly in flexion of the neck. In another dog, compression was lateral and could only be seen in the ventrodorsal view.

The macroscopic findings substantiated the radiologic findings. The cause of the spinal cord compression was in 8 dogs a decrease in the dorsoventral diameter of the orifice of the vertebral canal of 1 or 2 vertebrae in combination with deformation and elongation of 1 or several vertebral arches. In extension of the neck, the cervical spinal cord was squeezed between the anterior tip of the elongated vertebral arch and the caudodorsal rim of the body of the adjacent cranial vertebra.

Histologic examination was made of the spinal cord in 5 dogs and the compressive lesions that were found could explain the neurologic signs.

In the discussion, the question is raised as to why pain is not a prominent sign in dogs with the wobbler syndrome in contrast to in dogs with cervical disc protrusion. It is believed that the inflammatory foreign body reaction, triggered by the protruded calcified nucleus pulposus is the main cause of pain in the disc protrusion syndrome. In the wobbler syndrome there is no obvious inflammatory reaction in the epidural space.

Finally, the possible etiologic factors oC importance for the deformation oC the cervical vertebrae in wobblers are discussed. There are indications that both overnutrition and a genetic trait for rapid growth are of importance.

Vertebral facet jump in a goat: a case report

A 4-month-old goat manifesting front and rear limb ataxia was found to have a facet jump involving the first and second thoracic vertebrae. This injury caused severe narrowing of the vertebral foramen of the second thoracic vertebrae causing pressure on the spinal cord and signs of ataxia, overextension of hind limbs and periodic crossing of the hind limbs.

Clinical evaluation of metrizamide as a myelographic agent in the dog

Metrizamide, a new, water-soluble contrast agent, was clinically evaluated as a myelographic agent in 17 dogs. Nine dogs were given lumbar subarachnoid injections and six were given cisternal injections. Two dogs were given cisternal and lumbar injections; in one dog, both injections were given on the same day. The dosage ranged from 0.3 to 0.57 ml/kg of body weight, using an isotonic solution of metrizamide. Of eight dogs given cisternal injections, two experienced convulsive activity requiring diazepam treatment during the anesthetic recovery period. The lumbar injections did not cause convulsions. Satisfactory radiographic density persisted up to 45 minutes after injection, allowing time for several views to be obtained. In general, metrizamide appeared to be an adequate myelographic agent in the dog.

Cauda equina compression from lumbosacral malarticulation and malformation in the dog

Compression of the cauda equina from subluxation, stenosis, or spondylosis of the lumbosacral articulation was found in 20 dogs, 13 of which were German Shepherd Dogs or crossbred German Shepherd Dogs. Pain, posterior paresis, and urinary or fecal incontinence were the most frequent problems associated with the compression. Dorsal laminectomy was performed on 13 cases, with good to excellent results on 10 of these.

Spinal cord compression caused by a metastatic lesion from an aortic body tumour

An aortic body tumour in a 7-year-old wire-haired fox terrier with hind limb ataxia is described. A metastatic lesion in the dorsal arch of the eighth thoracic vertebra caused compression of the spinal cord. Radiographic techniques are discussed that enabled the position and extent of the primary tumour and its metastasis to be defined and allowed a provisional diagnosis of chemodectoma.

Atlanto-axial subluxation in five young cattle

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Clinical and histologic evaluation of bilateral hemilaminectomy and deep dorsal laminectomy for extensive spinal cord decompression in the dog

Various forms of 2 techniques for maximal decompression of the thoracolumbar spinal cord in dogs were evaluated clinically and histologically. Based on the results of this study, the veterinary surgeon could consider the following spinal decompression procedures: (1) deep dorsal laminectomy over 1 vertebra; (2) bilateral hemilaminectomy on 1 vertebra, with removal of articular processes and dorsal spinal plating; and (3) bilateral hemilaminectomy on 2 vertebrae, with the articular processes left intact. Of these 3, the 1st and 3rd techniques would probably be considered for use more often than the 2nd. Deep dorsal laminectomy over 2 vertebrae should be considered with reservation. Bilateral hemilaminectomy on 2 vertebrae, with rigid dorsal spinal plating and without articular processes at the ends of the defect, should not be used. Before using one of the techniques, the surgeon should consider the indications, advantages, and disadvantages for that technique.

An investigation into the genetics of 'wobbler disease' in thoroughbred horses in Britain

Sixty-seven TB horses in Britain suffering from clinical wobbler disease were divided into 5 groups, based on the presence or absence of pathological lesions and their nature. These groups were compared genetically with a control group of 67 TBs known not to exhibit signs of wobbling. Though analysed for both simple and complex modes of inheritance no evidence of a genetic basis was found in any group. The high breed incidence in TBs may be real or apparent. Considerably more male than female wobblers are reported. Other forms of possibly inherited ataxia in equidae are reviewed and reference is made to pathologically comparable conditions occurring in man and in the large breeds of dogs.

Evaluation of three techniques of ventral decompression of the cervical spinal cord in the dog

Three techniques for ventral decompression of the cervical spinal cord were performed on 21 dogs (3 groups of 7 dogs each). The techniques involved cutting various-sized defects in the vertebral bodies and disks of the cervical vertebral column. The defects were not filled with bone grafts. Two of the 3 techniques (short, wide defect and long, narrow defect) were successful, and the other technique (long, wide defect) gave questionable results.

Vertebral body deformation causing Wobbler syndrome in a Great Dane

This paper reports a case of cervical vertebral body deformation with gradually worsening posterior paresis in a Great Dane. The ventrocranial part of the body of the seventh cervical vertebra was severely eroded and deformed. This vertebra was tilted in relation to the sixth cervical vertebra producing a stenosis of the spinal canal which was demonstrated by myelography. Spondylolisthesis of the second type of G e a r y's classification was diagnosed. 99mTc-polyphosphate showed no concentration in the affected vertebra as would be found where bony tissues of different maturities are present, indicating the lack of effective repair. Dorsal hemilaminectomy resulted in no improvement.

Modified deep dorsal laminectomy in the dog

Spinal cord compression subsequent to radical laminectomy was investigated. A modified deep dorsal laminectomy technique was devised to allow extensive exposure and decompression of the canine spinal cord without undue hazard of postoperative fibrotic spinal cord compression. A previously described laminectomy technique was modified by the addition of spinal plating to avoid the occurrence of constrictive fibrosis.

Hemivertebra in the dog: clinical and pathological observations

The clinical and radiographic findings associated with the presence of hemivertebra ("wedge-shaped"vertebra) in small and brachycephalic breeds of dogs are reported together with the results of post mortem examination in the availabel cases. The condition is characterised clinically by progressive hind-leg weakness, spinal pain, abnormalities of the nervous system and evidence of muscle atrophy or other abnormalities of conformation. Confirmation of the clinical diagnosis is by radiography. It is suggested that the condition is congenital in origin. Breed incidences are reported. The occurrence of the disorder in certain families of dogs suggests also that it may be hereditary. Other congenital abnormalities are seen in some dogs affected by hemivertebrae.

Symposium on back problems in the horse. Backs-clinical signs

Diseases of the back of horse and man are not comparable owing to the great difference in anatomy and posture. Veterinary surgeons, particularly in the United Kingdom, are often requested to account for a poor performance due to suspected "back trouble" but a complete examination of the horse's back is most difficult and care must be taken first to exclude any limb or foot lesions. Diseases of the bones, nerves and muscles are briefly discussed. Diagnosis must be improved by new radiographic and biochemical tests before the significance of back lesions can be assessed or even treated.