Assessment of the utility of using intra- and intervertebral minimum sagittal diameter ratios in the diagnosis of cervical vertebral malformation in horses
Royal School of Veterinary Studies, University of Edinburgh. Veterinary Radiology & Ultrasound
(Impact Factor: 1.45).
02/2008; 49(1):1-6. DOI: 10.1111/j.1740-8261.2007.00308.x
Cervical vertebral malformation is one of the most common causes of ataxia in horses. The most important factor in the diagnosis of cervical vertebral malformation is the identification of cervical vertebral canal stenosis, but published data for minimum sagittal diameter ratios in adult horses are only available for C4-C7 intravertebral sites. Intra- and intervertebral sagittal diameter ratios at C2-C7 were evaluated in 26 ataxic horses, for which a complete clinical and neuropathological evaluation was undertaken. Eight of these horses were diagnosed with cervical vertebral malformation. In these horses the majority of compressive lesions were intervertebral. The mean sagittal diameter ratios of horses with cervical vertebral malformation were significantly smaller than those of horses without cervical vertebral malformation, and for an individual horse in our study, the site with the smallest intervertebral sagittal diameter ratio was always the site at which the spinal cord was compressed. Mean sagittal diameter ratio intravertebral site measurements of horses with cervical vertebral malformation were smaller than those of horses without cervical vertebral malformation; however, the site of compression could not be predicted from the data. For our dataset, horses with a sagittal diameter ratio of < or = 0.485 at any inter- or intravertebral site could be correctly classified as having cervical vertebral malformation, and sagittal diameter ratio measurements were an effective tool to identify at least one site of compression in an individual case.
Available from: Fernando L Garcia-Pereira
- "More recently, intervertebral sagittal ratio diameters have been investigated in horses with CVSM and reported results are promising. Although the compression could be localised using this procedure in a small number of animals, further studies are necessary to validate this technique (Hahn et al. 2008). "
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ABSTRACT: Localisation of spinal cord compression in horses with cervical vertebral stenotic myelopathy is inexact. Vertebral canal endoscopy has been used in man to localise spinal cord lesions and has the potential to become a useful diagnostic technique in horses.
To establish a surgical approach via the atlanto-occipital space to the cervical vertebral canal in equine cadavers and describe the endoscopic anatomy of the cervical epidural and subarachnoid spaces.
The cadavers of 25 mature horses were used to assess 3 surgical methods to approach the cervical vertebral canal, including 2 minimally invasive and one open technique. Once the approach had been made, a flexible videoendoscope was inserted into the epidural space (epiduroscopy) or the subarachnoid space (myeloscopy) and advanced caudally until the intervertebral space between C7 and T1 was reached.
The epidural and subarachnoid spaces could not be accessed reliably using the minimally invasive techniques. Furthermore, damage to the nervous tissues was a frequent complication with these procedures. The open approach allowed successful insertion of the videoendoscope into the epidural and subarachnoid spaces in all horses and no inadvertent damage was observed. Anatomical structures that could be seen in the epidural space included the dura mater, nerve roots, fat and the ventral internal vertebral venous plexus. In the subarachnoid space, the spinal cord, nerve roots, blood vessels, denticulate ligaments and external branch of the accessory nerve were seen.
Using the open approach, epiduroscopy and myeloscopy over the entire length of the cervical vertebral canal are possible in the mature horse. Potential relevance: Cervical vertebral canal endoscopy may become a valuable tool to localise the site of spinal cord injury in horses with cervical vertebral stenotic myelopathy and could aid in the diagnosis of other diseases of the cervical spinal cord.
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ABSTRACT: Arthropathy of the caudal cervical articular process joints (APJs) in the horse is documented as a cause of ataxia and paresis secondary to spinal cord compression. Enlargement of the caudal APJs is reported to increase with age, but there are no known associations of any other factors. No association of the degree of APJ enlargement with neurological signs seen has been documented. This study investigated the associations of cervical APJ enlargement at the C5-C6 and C6-C7 articulations with case subject details (breed, age, sex, usage) and clinical signs.
To ascertain if there are of any associations between: the subject details and enlargement of the caudal cervical APJs; and the degree of APJ enlargement and the presence and type of clinical signs.
There would be an effect of age, breed and usage on APJ grade, with no effect of sex. Association between grade and clinical signs seen was also investigated.
The radiographs of 122 horses qualified for inclusion. Horses were excluded if they were known to have a neck lesion cranial to C5-C6, or if the radiographs were rotated or of poor quality. In order to standardise the interpretation of APJ enlargement, a novel grading system was developed and used.
An association was found between age and APJ grade at C5-C6 but not C6-C7. There was no association between grade, breed, sex and usage, or clinical signs seen. Data also showed a trend for increasing enlargement the more caudal the APJ.
The data in this study support that the size of the caudal cervical APJ at the level of C5-C6, appear to increase with age, but this enlargement may not be significant. Enlargement cannot be associated with breed, sex or discipline of the horse at present, and specific grades and therefore degree of enlargement, cannot necessarily be assumed to be the cause of neurological deficits.
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ABSTRACT: Cervical stenotic myelopathy (CSM) is the most common cause of noninfectious spinal cord ataxia in horses. Intra-articular injection of corticosteroids into the facet joints of horses with CSM may relieve clinical signs of the disease process. However, there is a paucity of literature regarding the efficacy of facet injection therapy in horses with CSM. This retrospective study describes the return to normal function or improvement in performance of horses after ultrasound-guided cervical facet injection that had previously shown signs of ataxia, obscure lameness or neck pain, prior to injection.
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