CASE DESCRIPTION Over a 2-year period, 6 horses (4 Selle Français, 1 Hanoverian, and 1 Thoroughbred) were referred for evaluation of forelimb lameness. All horses had radiographic evidence of synostosis of the first and second ribs (SFSR).
CLINICAL FINDINGS For 1 horse, the SFSR was considered the probable cause of the lameness (grade 3/5), with a shortening of the cranial phase of the stride in the affected limb. For 3 horses, it was considered a possible cause of the lameness (grade 1/5) for the same reason. For 2 horses, SFSR was considered an incidental finding unassociated with any clinical signs. The 4 horses with lameness suspected as attributable to SFSR had a moderate to severe amount of irregularly marginated new bone formation at the site of the SFSR, with a cranial displacement of the first rib, compared with findings for the 2 horses in which the SFSR was considered incidental. A likely congenital abnormality of the first rib was first suspected on nuclear scintigraphy in the 1 horse for which it was performed or on radiography of the caudal cervical portion of the vertebral column (3 horses) or shoulder joint (2 horses).
TREATMENT AND OUTCOME The horse in which SFSR was considered the probable cause of the lameness was retired to the field and remained chronically lame. Two of the 3 horses in which SFSR was considered a possible cause of lameness received an IV infusion of tiludronate disodium and mesotherapy over the caudal cervical and cranial thoracic regions; both returned to competition but with poor results. One of the 2 horses with subclinical SFSR never developed lameness on the affected side. No follow-up information was available for the other 2 horses.
CLINICAL RELEVANCE SFSR can be an incidental finding in horses, with or without clinical manifestations. This abnormality should be considered as a differential diagnosis for horses with forelimb lameness and associated shortening of the cranial phase of the stride that fails to improve with diagnostic analgesic techniques.
OBJECTIVE To report history, findings from clinical examinations and diagnostic imaging, treatment, and outcomes associated with distal interphalangeal primary degenerative joint disease (DIP-PDJD) and to evaluate diagnostic usefulness and limitations of standing low-field MRI, relative to radiography and ultrasonography, for the diagnosis of DIP-PDJD in horses.
DESIGN Retrospective case series with nested evaluation study.
ANIMALS 12 client-owned horses.
PROCEDURES Medical records were reviewed, and data were collected regarding signalment, history, results of physical and diagnostic imaging examinations, treatments, and outcomes of horses that underwent radiography, ultrasonography, and standing MRI for DIP-PDJD. Findings from radiography, ultrasonography, and MRI were recorded, and abnormal findings were graded. The diagnostic usefulness of MRI, relative to radiography and ultrasonography, in the diagnosis of DIP-PDJD in horses was evaluated.
RESULTS A diagnosis of DIP-PDJD was established in 12 of 176 (6.8%) horses that underwent MRI examination of a foot for locomotor disorders. Radiography and ultrasonography enabled confirmation of DIP-PDJD in 3 of the 12 horses, and standing MRI enabled confirmation of DIP-PDJD in the remaining 9. Mean grade for thinning joint space and cartilage were significantly greater when determined with MRI, compared with radiography. Mean grade for osteophytes and periarticular bone remodeling were significantly greater when determined with radiography and ultrasonography, compared with MRI.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that DIP-PDJD can be challenging to detect with routine imaging, especially when synovial effusion and periarticular new bone formation are absent. Standing low-field MRI represents a potentially useful diagnostic tool to diagnose advanced DIP-PDJD in horses.
To quantify the degree of dural compression and assess the association between site and direction of compression and articular process (AP) size and degree of dural compression with CT myelography.
26 client-oriented horses with ataxia.
Spinal cord-to-dura and AP-to-cross-sectional area of the C6 body ratios (APBRs) were calculated for each noncompressive site and site that had > 50% compression of the subarachnoid space. Site of maximum compression had the largest spinal cord-to-dura ratio. Fisher exact test and linear regression analyses were used to assess the association between site and direction of compression and mean or maximum APBR and spinal cord-todura ratio, respectively.
Mean ± SD spinal cord-to-dura ratio was 0.31 ± 0.044 (range, 0.20 to 0.41) for noncompressive sites and 0.44 ± 0.078 (0.29 to 0.60) for sites of maximum compression. Sites of maximum compression were intervertebral and extra-dural, most frequently at C6 through 7 (n = 10), followed by C3 through 4 (6). Thirteen horses had dorsolateral and lateral compression at the AP joints, secondary to AP (n = 7) or soft tissue proliferation (6). Site significantly affected direction of compression, and directions of compression from occiput through C4 were primarily ventral and lateral, whereas from C6 through T1 were primarily dorsal and dorsolateral. No linear relationship was identified between mean or maximum APBR and spinal cord-to-dura ratio.
CONCLUSIONS AND CLINICAL RELEVANCE
CT myelography may be useful for examination of horses with suspected cervical compressive myelopathy. Degree of compression can be assessed quantitatively, and site of compression significantly affected direction of compression.
To describe articular process joints (APJs) of the cervical spine in horses on the basis of CT and to determine whether abnormalities were associated with clinical signs.
86 client-owned warmblood horses.
Horses that underwent CT of the cervical spine between January 2015 and January 2017 were eligible for study inclusion. Medical records were reviewed for age, body weight, breed, sex, history, clinical signs, and CT findings. Horses were divided into 3 case groups and 1 control group on the basis of clinical signs.
70 warmblood horses were cases, and 16 were controls. Abnormalities were more frequent from C5 through T1 and were severe in only horses from the case group. Narrowing of the intervertebral foramen was common in horses in the case group (85.7%), often owing to enlarged, misshaped articular processes, followed by degenerative changes, periarticular osteolysis, cyst-like lesions, and fragmentation. High articular process-to-vertebral body (C6) ratio (APBR) and high-grade narrowing of the intervertebral foramen and periarticular osteolysis were noted for horses with forelimb lameness or signs of cervical pain or stiffness. No association was identified between APBR and age or sex. An APBR > 1.5 was found in only horses in the case group, and 32.3% of APJs with APBRs > 1.5 did not have any degenerative changes and periarticular osteolysis.
CONCLUSIONS AND CLINICAL RELEVANCE
CT was useful to identify abnormalities of the APJs of the cervical spine. An association existed between CT findings and clinical signs. The APJs can be enlarged without concurrent degenerative changes.