Objective—To compare radiographic morphology of the atlantoaxial region between Cavalier King Charles Spaniels (CKCSs) and dogs of other breeds and determine whether there was an association between radiographic morphology of the atlantoaxial region and syringomyelia in CKCSs.
Animals—65 CKCSs and 72 dogs of other breeds.
Procedures—The amount that the spinous process of the axis overlapped the dorsal arch of the atlas, the relative size of the spinous process of the axis, and the amount of widening of the atlantoaxial joint that occurred when the neck was moved from a neutral to a flexed position were measured on lateral radiographic projections of the atlantoaxial region. Magnetic resonance images were reviewed to identify CKCSs with syringomyelia.
Results—The amount of overlap of the atlas and axis and the relative size of the spinous process of the axis were significantly smaller in CKCSs than in dogs of other breeds. However, the amount of widening of the atlantoaxial joint that occurred when the neck was moved from a neutral to a flexed position was not significantly different between groups, and no association was detected between syringomyelia and excessive atlantoaxial joint space widening or between syringomyelia and an excessively small axial spinous process.
Conclusions and Clinical Relevance—Results suggested that radiographic morphology of the atlantoaxial region in CKCSs differs from morphology of that region in dogs of other breeds, but that these differences do not account for why some CKCSs develop syringomyelia and others do not.
Case Description—A 2-year-old spayed female domestic shorthair cat was examined because of bilateral thoracic limb weakness of acute onset.
Clinical Findings—Clinical signs included muscle atrophy, paresis, depressed spinal reflexes, hyperesthesia of the thoracic limbs, and reduced jaw muscle tone. Pelvic limb reflexes were normal. Results of a neurologic examination were suggestive of multifocal lesions involving both brachial plexuses and the trigeminal nerves. Abnormal nerve conduction across the brachial plexus and delayed late potentials were found on electrodiagnostic testing, and diffuse subclinical involvement of other regions of the peripheral nervous system was confirmed on the basis of abnormal electromyographic findings for the masticatory muscles and conduction block of the peroneal nerve.
Treatment and Outcome—No specific treatments were given, and neurologic signs resolved within a month. A relapse occurred 2 months after the first episode, with clinical signs affecting both the pelvic and the thoracic limbs on this occasion. Again, the condition resolved without specific treatment, and 13 months after the initial episode, the cat reportedly was normal.
Conclusions and Clinical Relevance—Findings suggested that brachial plexus neuropathy can be a multifocal disease in cats, even if clinically apparent neurologic deficits are initially subtle or absent, and that electrodiagnostic techniques can be used to identify subclinical involvement of the peripheral nerves.
Case Description—A 1-month-old female alpaca was examined because of progressive clinical signs consistent with an intracranial lesion.
Clinical Findings—Clinical signs included signs of depression, lethargy, tetraparesis, and neck weakness. Two large isointense intracranial masses could be seen on T1-weighted magnetic resonance images. On T2-weighted images, the masses contained concentric rings of hypointense and hyperintense material.
Treatment and Outcome—2 abscesses were removed via a craniotomy that incorporated removal of the sagittal crest and surrounding skull and transection of the sagittal sinus. The bony deficit was replaced with polypropylene mesh. The alpaca recovered within 2 weeks and was fully integrated into the herd within 1 month after surgery.
Clinical Relevance—Findings indicated that surgical removal is a feasible means of successfully treating intracranial abscesses in juvenile alpacas.
Objective—To determine the effects of syringomyelia on electromyography (EMG) findings, somatosensory-evoked potentials (SEPs), and transcranial magnetic motor-evoked potentials (TMMEPs) in Cavalier King Charles Spaniels (CKCSs).
Animals—27 client-owned CKCSs that underwent prebreeding magnetic resonance imaging screening or investigation of clinical signs consistent with syringomyelia.
Procedures—In dogs with (n = 11) and without (16) magnetic resonance imaging-confirmed syringomyelia, the median nerve in each thoracic limb was stimulated and SEPs were recorded over the C1 vertebra; onset latency and latency and amplitude of the largest negative (N1) and positive (P1) peaks were measured. The TMMEPs were recorded bilaterally from the extensor carpi radialis and tibialis cranialis muscles; onset latencies in all 4 limbs were measured. Bilateral systematic needle EMG examination was performed on the cervical epaxial musculature, and the number of sites with spontaneous activity was recorded.
Results—In dogs with syringomyelia, amplitudes of N1 and P1 and the amplitude difference between P1 and N1 were significantly smaller than those recorded for dogs without syringomyelia (approx 2-fold difference). No difference in SEP latencies, TMMEP latencies, or the proportion of dogs with > 2 sites of spontaneous activity detected during EMG examination was detected between groups.
Conclusions and Clinical Relevance—Results indicated that SEP amplitude at the C1 vertebra was a more sensitive measure of spinal cord function in CKCSs with syringomyelia, compared with results of EMG or TMMEP assessment. Measurement of SEP amplitude may have use as an objective assessment of the evolution and treatment of this disease.
Objective—To evaluate the numbers and proportions of olfactory ensheathing cells (OECs) in cell cultures derived from the olfactory bulb (OB) and olfactory mucosa of dogs.
Procedures—OB tissue and olfactory mucosa from the nasal cavity and frontal sinus were obtained from euthanatized dogs and prepared for cell culture. At 7, 14, and 21 days of culture in vitro, numbers and proportions of OECs, astrocytes, and fibroblasts were determined via immunocytochemistry. Antibody against the low-affinity nerve growth factor receptor p75 was used to identify OECs, antibody against glial fibrillary acidic protein was used to identify astrocytes, and antibody against fibronectin was used to identify fibroblasts.
Results—Cultured OECs derived from the olfactory mucosa of the nasal cavity and frontal sinus had similar characteristics. However, whereas OECs in the OB cell cultures constituted approximately 50% of the cells at 7 days and approximately 75% at 21 days the proportion of OECs in cultures derived from both mucosal types was much lower, with approximately 40% OECs at 7 days and approximately 25% at 21 days. Analysis of OEC numbers revealed that these changes were accompanied by corresponding decreases and increases in the population of cells with fibronectin receptors.
Conclusions and Clinical Relevance—Although olfactory mucosal cell cultures yielded a sufficient number of OECs for spinal cord transplantation procedures in dogs, modification of culture conditions would be required to ensure that the derived cell population contained a sufficient proportion of OECs.
Objective—To determine whether magnetic resonance
imaging findings in dogs with paraplegia
caused by thoracolumbar intervertebral disk extrusion
were predictive of clinical outcome.
Design—Retrospective case series.
Procedure—Medical records and magnetic resonance
images were reviewed; clinical outcome was
classified as successful (regained ability to walk with
no more than mild neurologic deficits) or unsuccessful
(severe neurologic deficits persisted). The prognostic
value of magnetic resonance imaging was
compared with prognostic value of deep pain perception,
duration of clinical signs, and rate of onset of
Result—33 (43%) dogs had areas of hyperintensity of
the spinal cord greater than or equal to the length of
the L2 vertebral body on T2-weighted magnetic resonance
images. All 44 dogs without areas of hyperintensity
on T2-weighted images had a successful outcome,
but only 18 of the 33 (55%) dogs with an area
of hyperintensity did. Only 5 of 16 dogs with an area
of hyperintensity that had also lost deep pain perception
had a successful outcome. The odds ratio for an
unsuccessful outcome for a dog with an area of
hyperintensity (29.87) was higher than the odds ratio
for a dog that had lost deep pain perception (5.24).
Duration and rate of onset of clinical signs were not
associated with clinical outcome.
Conclusions and Clinical Relevance—Findings suggest
that results of magnetic resonance imaging can
be used to predict clinical outcome in dogs with paraplegia
caused by intervertebral disk extrusion. (J Am
Vet Med Assoc 2005;227:1454–1460)
Objective—To compare long-term survival and quality of life data in dogs with clinical signs associated with a congenital portosystemic shunt (CPSS) that underwent medical or surgical treatment.
Design—Prospective cohort study.
Animals—124 client-owned dogs with CPSS.
Procedures—Dogs received medical or surgical treatment without regard to signalment, clinical signs, or clinicopathologic results. Survival data were analyzed with a Cox regression model. Quality of life information, obtained from owner questionnaires, included frequency of CPSS-associated clinical signs (from which a clinical score was derived), whether owners considered their dog normal, and (for surgically treated dogs) any ongoing medical treatment for CPSS. A Mann-Whitney U test was used to compare mean clinical score data between surgically and medically managed dogs during predetermined follow-up intervals.
Results—97 dogs underwent surgical treatment; 27 were managed medically. Median follow-up time for all dogs was 1,936 days. Forty-five dogs (24 medically managed and 21 surgically managed) died or were euthanized during the follow-up period. Survival rate was significantly improved in dogs that underwent surgical treatment (hazard ratio, 8.11; 95% CI, 4.20 to 15.66) than in those treated medically for CPSS. Neither age at diagnosis nor shunt type affected survival rate. Frequency of clinical signs was lower in surgically versus medically managed dogs for all follow-up intervals, with a significant difference between groups at 4 to 7 years after study entry.
Conclusions and Clinical Relevance—Surgical treatment of CPSS in dogs resulted in significantly improved survival rate and lower frequency of ongoing clinical signs, compared with medical management. Age at diagnosis did not affect survival rate and should not influence treatment choice.
OBJECTIVE To investigate associations between recovery of locomotion and putative prognostic factors in dogs with loss of deep pain perception in the pelvic limbs caused by intervertebral disk herniation (IVDH).
DESIGN Prospective cohort study.
ANIMALS 78 client-owned dogs evaluated for IVDH that underwent spinal decompression surgery.
PROCEDURES Dogs with complete loss of deep pain perception in the pelvic limbs and tail underwent routine examinations, advanced imaging, and spinal decompression surgery in accordance with standards of practice and owner consent. For each dog, information was prospectively collected on duration of clinical signs prior to onset of paraplegia; delay between onset of paraplegia and initial referral evaluation; date of recovery of locomotion, death, or euthanasia (3-month follow-up period); and whether dogs had received corticosteroid drugs before surgery. Severity of spinal cord compression at the lesion epicenter was measured via CT or MRI.
RESULTS 45 of 78 (58%) of dogs recovered the ability to ambulate independently within 3 months after spinal decompression surgery. No evidence of prognostic value was identified for any of the investigated factors; importantly, a greater delay between onset of paraplegia and referral evaluation was not associated with a poorer prognosis.
CONCLUSIONS AND CLINICAL RELEVANCE In this group of dogs with IVDH, immediacy of surgical treatment had no apparent association with outcome. The prognosis for recovery may instead be strongly influenced by the precise nature of the initiating injury.