Long-Term Prognosis for Return to Athletic Function after Interspinous Ligament Desmotomy for Treatment of Impinging and Overriding Dorsal Spinous Processes in Horses: 71 Cases (2012–2017)

Introduction: Impinging/overriding dorsal spinous processes (ORDSP) is a common cause of thoracolumbar pain in horses and interspinous ligament desmotomy (ISLD) has been described as a surgical treatment. This study aims to determine long-term prognosis for performance following ISLD and determine if radiographic or scintigraphic grade affected return to performance.

Materials and Methods: Records were reviewed for signalment, physical examination, gait evaluation, and number of interspinous spaces treated. Preoperative radiographic and scintigraphic images were evaluated with established grading scales. Follow‐up was obtained via telephone questionnaire. Prognostic value of the number of affected interspinous spaces, radiographic grading, and scintigraphic grading was tested using a χ2 test.

Results: A total of 71 horses with ORDSP underwent ISLD. 51/ 56 (91.1%) horses available for follow-up returned to performance, with a median follow-up of 35 months (range 8–64). 24/51 horses (47.1%) achieved lower performance and 27 of 51 horses (52.9%) achieved equivalent or higher performance. Lower performance was attributed to recurrent back pain in 9/ 24 horses (37.5%) and lameness in 9/ 24 horses (37.5%). Owners of 44/ 56 horses (78.6%) were satisfied with postoperative performance and owners of 46/ 56 horses (82.1%) would recommend the procedure in the future. 47/56 owners (83.9%) reported complete compliance with the rehabilitation protocol recommended postoperatively. None of the variables tested influenced postoperative performance.

Discussion/Conclusion: Combined with controlled rehabilitation, ISLD alleviated discomfort from ORDSP regardless of the severity based upon diagnostic imaging and allowed return to some level of performance. However, return to equivalent or higher performance was reduced compared with a previous report.

Acknowledgment: There was no proprietary interest or funding provided for this project.