A study of impingement of thoracic dorsal spinous processes in young Warmbloods prior to training

Summary Background The development of impinging dorsal spinous processes (IDSP) is not fully understood. To the authors' knowledge, no studies have previously been made to clarify the occurrence of IDSP in Warmblood horses just before onset of ridden training. Objectives The purpose of this study was to investigate if IDSP occurred in a population of 2‐year‐old unridden Warmblood horses. Study design Cross‐sectional study. Methods Twenty‐nine horses had a radiographic examination performed of the dorsal spinous processes (DSPs) from T10 to L1. Interspinous space width was measured from T10 to L1. Interspinous spaces were defined as narrow if the width was <4 mm. Prevalence of each gender group was calculated. Mean interspinous space width was calculated. The DSPs of the horses were graded using a radiological grading. Results Mean ± SD age of the horses was 951 days ± 59 (median: 564). The prevalence of IDSP within each gender group was 2 mares (33.3%), 4 geldings (33.3%) and 2 stallions (18.2%). The mean width of the narrowest and the widest interspinous spaces ± SD was 8.05 mm ± 4.08 and 20.37 mm ± 3.25, respectively. Eight horses (27.6%) had IDSP. The mean number of narrow interspinous spaces in affected horses was 1.88 (range 1–4). The interspinous space of T15–T16 was the space with the mean narrowest width (8.05 mm ± 4.08). Narrow interspinous spaces were found between T15 and T16 ( n = 4), T16 and T17 ( n = 4), T17 and T18 ( n = 4) and T18 and L1 ( n = 3). Radiological grading was performed and found 7 horses with grade 1 and 1 horse with grade 3. Main limitations Small sample size. Conclusion This study concluded that IDSP between T10 and L1 was present in 27.6% in a population of young Warmblood horses, thereby IDSP can be developed in Warmblood horses before the onset of ridden training.