We compared the frequency and severity of osteochondrosis lesions in young Thoroughbred horses with cervical stenotic myelopathy (CSM) vs that in clinically normal Thoroughbreds of the same age. All lesions of the cervical vertebrae and appendicular skeleton were classified histologically as osteochondrosis or nonosteochondrosis and were measured for severity. Minimal sagittal diameter was significantly smaller in horses with CSM from C2 through C6; no difference was detected at C7. Severity of cervical vertebral osteochondrosis was greater in the horses with CSM, however frequency was not different. Frequency and severity of nonosteochondrosis lesions were not different in cervical vertebrae or appendicular skeleton. Frequency and severity of appendicular skeleton osteochondrosis lesions were both greater in horses with CSM. Osteochondrosis and nonosteochondrosis lesions were more severe on facets at sites of compression than on facets at noncompressed sites in horses with CSM. However, compression was also observed at sites with no articular facet lesions. The association of widespread osteochondrosis and spinal canal narrowing with CSM suggests CSM may represent a systemic failure in the development or maturation of cartilage and bone.

Lumbar and thoracic vertebrae of the extinct horse, Equus occidentalis, were examined for gross and radiographic evidence of overriding spinous processes. Of 2,661 vertebrae examined, 580 had intact spinous processes. Thirty-six intact spinous processes, which appeared grossly similar to overriding spinous processes in the modern domestic horse, E caballus caballus, were radiographed. Of these 36 vertebrae, 2 had radiographic signs compatible with a radiographic diagnosis of overriding spinous processes, ie, radiographically observed lysis and/or sclerosis. Seemingly, weight bearing or other stresses imposed by human beings may not have induced the signs of overriding spinous processes.

Magnification of cervical radiographs prevents accurate interpretation of vertebral canal absolute minimum sagittal diameter (MSD) values and application of the established MSD values for diagnosis of cervical stenotic myelopathy (CSM). Variability in MSD determination in human beings, owing to radiographic magnification, is minimized by assessing a ratio of the vertebral canal diameter to the sagittal width of the vertebral body. This relative measurement technique improves the accuracy of diagnosis of cervical spinal stenosis in human beings. The MSD of the vertebral canal was determined in 50 horses with CSM and 50 control horses, using a radiopaque marker method for correction of magnification. In addition, a ratio of the absolute MSD to the sagittal width of the vertebral body and a ratio of the absolute MSD to the length of the vertebral body were determined in 100 CSM-affected and 100 control horses. Response operating characteristic curve analysis of each method determined that the sagittal ratio method of canal diameter assessment provided the most accurate interpretation of cervical radiographs for diagnosis of CSM, with sensitivity and specificity of larger than or equal to 89% at each vertebral site. The accuracy of the ratio method, without consideration of bony malformation, supports the importance, and perhaps prerequisite, of generalized vertebral canal stenosis in the pathogenesis of CSM. Subjective evaluation of bony malformations from cervical radiographs of 100 CSM-affected horses and 100 control horses indicated that CSM-affected horses have more severe bony malformation than do control horses. However, moderate to marked degenerative joint disease of the articular processes was frequently observed in control horses. Subjective evaluation of bony malformation does not distinguish between CSM-affected and unaffected horses.

In a 5-year prospective study, computed tomographic (CT) morphometry of the lumbosacral vertebral canal was performed on 42 large-breed dogs (21 controls and 21 dogs with lumbosacral stenosis). Dogs were allotted to 4 groups. Group 1 (n = 13) consisted of cadaver specimens obtained from dogs that died or were euthanatized for reasons unrelated to the spine; group 2 (n = 8) consisted of live dogs with no history of clinical signs related to the spine and with normal neurologic examination findings; group 3 (n = 10) consisted of dogs with surgically confirmed lumbosacral stenosis; and group 4 (n = 11) consisted of dogs with suspected lumbosacral stenosis that were managed conservatively. The CT scans were performed, using 5-mm contiguous slices obtained perpendicular to the vertebral canal, from the midbody of the 5th lumbar vertebra through the caudal endplate of the sacrum (L5-S3). Lumbosacral lordosis was minimized in all dogs by positioning them in dorsal recumbency with the hind limbs flexed. A tuberculin syringe calibration phantom was placed within the scanning field of view, parallel to the axis of the spine. In each dog, 11 CT slice locations within the lumbosacral spine were evaluated. At each slice location, sagittal plane diameter, dorsal plane diameter, and transverse area of the vertebral canal, vertebral body, and calibration phantom were measured, using the CT computer's software programs for distance and area calculation. Window/level settings were constant, and all measurements were made by the same operator (JCJ). Accuracy of calibration phantom CT measurements was 100% for sagittal and dorsal plane diameter and was 85% for transverse area. In control dogs (groups 1 and 2), vertebral canal dimensions were significantly (r greater than or equal to 0.50, P less than or equal to 0.0001) correlated with vertebral body dimensions, but not with dog weight or age. There were no significant differences between group 1 vs group 2, and group 3 vs group 4 for all absolute vertebral canal dimensions and for 5 ratios of vertebral canal to correlated vertebral body dimensions (general linear model for ANOVA). Pooled control dogs (n = 21) and those with lumbosacral stenosis (n = 21) were compared, and significant differences were not identified for absolute canal dimensions. Significant differences between control dogs and those with lumbosacral stenosis were identified in the ratios of vertebral canal transverse area to vertebral body sagittal diameter (P less than or equal to 0.01) and vertebral canal transverse area to vertebral body transverse area (P less than or equal to 0.001). For both these ratios, analysis by slice location identified significant differences (P < 0.05) between pooled groups at the caudal pedicles of L5 and L6. For the ratio of transverse canal area to sagittal vertebral body diameter, differences (P less than or equal to 0.05) also were found at the cranial pedicle of L7. These results indicate that: CT is an accurate method for performing morphometry of the canine lumbosacral spine; vertebral canal dimensions can be corrected for differences in dog size by calculating ratios of vertebral canal to vertebral body dimensions; statistical comparisons, using such corrected vertebral canal dimensions, may reveal differences not evident when absolute vertebral canal dimensions are used; and corrected transverse area of the vertebral canal differs in large-breed dogs with lumbosacral stenosis vs normal controls. Morphometric differences identified at more than 1 vertebral level support a theory that multilevel congenital or developmental stenosis of the lumbosacral vertebral canal may be a predisposing or contributing factor in large-breed dogs with acquired lumbosacral stenosis.

Three laparoscopic procedures were performed on each of 6 adult jersey cows in the first trimester of gestation to describe normal laparoscopic anatomy of the bovine abdomen. Also, a technique for laparoscopy of the cranioventral portion of the abdomen was described. Right paralumbar fossa, left paralumbar fossa, and cranioventral midline laparoscopy were performed 72 hours apart on each cow. Physical examination findings, CBC, serum biochemical analysis, and peritoneal fluid analysis before and 72 hours after the first surgery were used to assess the effects of the procedures on the cows. Exploratory celiotomy was performed 2 weeks after the last laparoscopy. The cows were then reexamined 6 weeks after the last procedure. The t-test for paired data was used for statistical analysis; the level of significance was P < 0.05. Laparoscopy was performed without complication in all cows. Adverse effects of laparoscopy, individually or serially, were not observed. Significant differences were not found between CBC, serum biochemical, and peritoneal fluid variables taken before and 72 hours after surgery.

We compared the frequency and severity of osteochondrosis lesions in young Thoroughbred horses with cervical stenotic myelopathy (CSM) vs that in clinically normal Thoroughbreds of the same age. All lesions of the cervical vertebrae and appendicular skeleton were classifiedhistologically as osteochondrosis or nonosteochondrosis and were measured for severity. Minimal sagittal diameter was significantly smaller in horses with CSM from C2 through C6; no difference was detected at C7. Severity of cervical vertebral osteochondrosis was greater in the horses with CSM, however frequency was not different. Frequency and severity of nonosteochondrosis lesions were not different in cervical vertebrae or appendicular skeleton. Frequency and severity of appendicular skeleton osteochondrosis lesions were both greater in horses with CSM. Osteochondrosis and nonosteochondrosis lesions were more severe on facets at sites of compression than on facets at noncompressed sites in horses with CSM. However, compression was also observed at sites with no articular facet lesions. The association of widespread osteochondrosis and spinal canal narrowing with CSM suggests CSM may represent a systemic failure in the development or maturation of cartilage and bone.

One hundred two dogs without known gastric lesions were evaluated to establish a reference range of gastric rugal fold thickness (millimeters). Mucosal folds were measureable for 63 examinations, and the length of the second lumbar vertebra was measured for 61 of the 63 (centimeters). Body weight was available in the case records of 29 dogs. Measurements of the mucosal folds were related to body weight (n = 29) and length of the second lumbar vertebra (n = 61) by use of linear regression analysis. Reference range of normal gastric mucosal fold thickness, 1 to 8 mm, was defined by this study for dogs of any breed weighing between 2 and 50 kg.