To (1) describe a safe, efficient surgical technique for subtotal ostectomy (SO) of diseased dorsal spinal processes (DSP) of the caudal thoracic vertebrae with the horse standing and (2) report outcome.

Study Design

Case series.


Horses (n = 23) with reduced performance caused by impingement of the DSP of the caudal thoracic vertebrae.


Affected DSP were resected through a dorsal median incision with the horse standing, sedated, and the surgical site desensitized with local anesthetic. Radiography was used to confirm removal of impinging bone before wound closure.


No serious complications occurred. Outcome was obtained for 22 horses. At <1 year, 19 horses (86%) returned to full athletic function, 2 horses (9%) improved but had failed to return to full function, 1 horse had no improvement. At >1 year, 2 horses that had returned to full athletic function were unable to function at full capacity; 1 was considered improved, but the other had not improved. Athletic function in 1 horse improved 6 months after surgery, but at 2.5 years was no better than before surgery.


Subtotal ostectomy of impinging DSPs can be performed with good results with the horse standing.