33rd Annual Scientific Meeting proceedings

Introduction
The purposes of this study were to investigate the prevalence and severity of radiographic abnormalities of the interspinous spaces (ISSs) in the thoracolumbar tract of unbroken yearlings and to compare the radiographic findings with a group of trained Thoroughbred without perceived back pain.

Material and methods
One-hundred-two clinically normal thoroughbred horses without perceived back pain were included in the study, including 47 untrained yearlings (group Y) and 55 trained horses (group T). Each horse underwent a radiological investigation of the thoracolumbar spine (T7-L3). Radiographs were evaluated for narrowing, increased opacity, presence of radiolucency and modelling of the cranial or caudal margins of two contiguous dorsal spinous processes. A radiographic score (0-3) for each ISS was assigned for narrowing, increased opacity, radiolucent area, modelling and impingement, calculated per space and per horse. Statistical analysis was performed to detect differences between the groups.

Results
Impingement was present in 6.4% (42/658) of group Y and 11.6% (90/770) in group T. The median number of impingements was 1(0-6) and 1.5(0-9) for group Y and group T, respectively. No differences were found between group Y and group T for number of radiographic abnormalities, scores, and total score for either per horse or per tract.

Conclusion
This study demonstrated the high prevalence of radiographic abnormalities in both groups. No detectable difference was found, hinting at a congenital more than acquired aetiology.