DSP impingement, colloquially known as “Kissing Spines” is a common cause of back pain in horses (1). The normal spaces between these uppermost process of the horse’s vertebral column are reduced and pain arises from the bone to bone contact and disruption to the interspinous ligament between the processes. (See image 1).
Traditional treatment options include conservative and surgical therapies. The former include physiotherapy and rehabilitative exercise programs to reduce muscle spasm and recruit core muscle strength, systemic anti-inflammatory medications and shock wave therapy. Under radiographic guidance corticosteriods can also be placed between or directly adjacent to the impinging DSPs. Severe cases or those which are refractory to conservative treatment can be treated surgically by resection of portions of the affected processes.
Historically the surgical procedure was performed under general anaesthesia (2). Currently there is a move to carry out the surgery under sedation and local anaesthetic to remove the risks of general anaesthesia (3). This standing technique has recently been reported to be associated with fewer complications and improved healing of the surgical wound (4). Despite this reported improvement there is a continued search for a less invasive treatment option as the average time for a return to ridden exercise is five months following standing surgery.
Recently a minimally invasive technique was devised by Richard Coomer and colleagues (5). This procedure sections the ligament between the DSPs but retains the bone contour. It can be performed through small skin incisions adjacent to each interspinous space and negates the need for deep dissection of the surrounding soft tissues. Convalescence is only a couple of weeks and ridden work can be resumed more rapidly. Early results are encouraging but further studies are required to ascertain the lasting effects of the technique.
At the clinic we routinely perform the bone resection technique in standing horses (see image 2). Careful consideration to precise diagnosis is given in each case as the presenting signs of back pain in horses is very varied. Crucially, the severity of the radiographic appearance of equine DSPs does not correlate well with the clinical signs and additional diagnostic techniques are required to confirm the indication for surgery. These include assessing the horse under saddle before and after injecting local anaesthetic around the affected areas and performing a bone scan of the spine to identify additional or confounding pathology.
If you have any questions about this blog or are concerned that your horse may be suffering from back pain, please do not hesitate to contact the clinic for advise.