Radiographic abnormalities of the thoracolumbar spinous processes do not differ between yearling and trained Thoroughbred horses without perceived back pain

Abstract

OBJECTIVE The purpose of this prospective study was to investigate the prevalence and severity of radiographic abnormalities of the interspinous spaces (ISSs) in the thoracolumbar vertebral column of unbroken yearlings and to compare these findings with a group of older trained Thoroughbred horses without perceived back pain. ANIMALS Yearlings (n = 47) and trained horses (55); 102 total. PROCEDURES Each horse underwent a digital radiographic study of the thoracolumbar vertebral column (T7–L3) and each space graded for narrowing of the ISSs, increased opacity, radiolucency, and modeling of the cranial and caudal margins of 2 contiguous dorsal spinous processes (DSPs). This generated both an individual anatomical space score for each space and a total score for each horse for subsequent comparison. Statistical analysis of the results was then undertaken. RESULTS Narrowing and impingement were detected in a third of the examined ISSs, while DSP increased opacity, radiolucencies, and modeling were found in over half of the yearlings. The median total score per horse was 33 (0 to 96) in the yearlings and 30 (0 to 101) in trained horses, indicating no significant difference in radiographic abnormalities (P = .91). Likewise, the median total score per anatomical space was 112 (25 to 259) and 127.5 (24 to 284) in the yearlings and trained horses (P = .83). No differences were found between the groups for number of radiographic abnormalities, scores, and total score. CLINICAL RELEVANCE This study reported the incidence of DSP radiographic abnormalities in Thoroughbred horses. The absence of difference in occurrence between yearlings and older horses supported a developmental rather than acquired etiology.

Should radiographs of the thoracolumbar spine remain part of the pre‐purchase examination?

“…Consequently, in this population, there did not appear to be a congenital narrowing of the SPs (Sinding & Berg, 2010). Pressanto et al (2023) stated that the absence of difference in the occurrence of radiographic findings of the SP between yearlings and older horses supported a developmental rather than acquired aetiology (Pressanto et al, 2023).…”

“…Both studies conclude that the likelihood of an acquired disease in impinging SPs is small. However, in Sinding and Berg (2010), it was thought more likely congenital, whereas Pressanto et al (2023) state a developmental aetiology. Long-term follow-up studies, of the same population, from foal to yearling to adult, are needed in order to further the aetiology.…”

Computed tomographic study analysing functional biomechanics in the thoracolumbar spine of horses with and without spinal pathology

“…The aetiology of ORSPs is not fully understood. Whilst there is no evidence for radiographic changes in the area of the spinous processes (SPs) in Warmblood foals, ORSPs were detected in untrained Thoroughbred yearlings (Pressanto et al, 2023;Sinding & Berg, 2010).…”

“…Fused SPs are found more frequently in older horses . A developmental or genetic component of the condition is the subject of current debate (Patterson Rosa et al, 2022;Pressanto et al, 2023). Alterations of the interspinous ligament structure and innervation have been associated with the pathogenesis of ORSPs (Ehrle et al, 2019).…”

International survey of equine orthopaedic specialists reveals diverse treatment strategies for horses with overriding spinous processes

“…[7][8][9][10] ORDSPs are described in asymptomatic ridden horses as well as in horses with thoracolumbar pain. 5,[11][12][13][14][15] Clinical signs are often non-specific and range from loss of performance and pain on palpation to subtle gait alterations or behavioural changes. 1,16,17 Radiographic and scintigraphic evidence for ORDSPs is not necessarily correlated with clinical signs of thoracolumbar pain.…”