Mid Rivers Equine Centre Veterinarian Dr. Hartman performed an interspinous ligament desmotomy (ISLD) to correct kissing spines on an eight year old TB mare. ISLD is a minimally invasive surgery that severs the interspinous ligaments located between each dorsal spinous process. This surgical technique was developed to relieve tension on pain receptors that are located where the interspinous ligament attaches to the spinous processes. Unexpectedly, researchers discovered that the technique increased the space between the dorsal spinal processes. Using this significant finding, surgeons are able to relieve pain and correct impinged or overlapping spinous processes, also known as “kissing spines.”
Interspinous Ligament Desmotomy (ISLD)
ISLD is a minimally invasive surgery where the interspinous ligament is cut. It is performed standing under sedation and local anesthetic. ISLD surgery “aims to remove pain and facilitate spinal remobilization.” The procedure is followed by 7 weeks between surgery and riding under saddle. ISLD is considered a superior long-term solution compared to other medical options however, it is not the only option for treating kissing spines. Other options for treating kissing spines are:
Traditionally, injections are the first step in relieving back pain associated with kissing spines. Corticosteroids are injected into the space between the dorsal spinous processes to reduce inflammation and pain. With this treatment, more than half of horses are expected to experience reoccurring back pain within the first year and require additional injections or treatment. While not curative, injections are an effective treatment and they avoid the convalescence that is required after surgery.
Improving Topline Strength
It has been observed that horses who come off a period of rest can have a reoccurrence of back pain. Veterinarians suggest that the loss in topline strength from the lack of conditioning is a contributing factor to back pain associated with Dorsal Spinous Process (DSP) Impingement. Topline strength can be improved with exercise and modifying nutrition.
Shock Wave Therapy
Shock wave therapy uses high intensity pressure waves for healing. The shock wave produces a biological response that releases growth factors and induces new blood vessel formation to promote healing.
Dorsal Spinous Process (DSP) Resection
DSP Resection is a surgical procedure where one or more of the dorsal spinous processes are removed to create space and alleviate pain. This surgery can be performed under general anesthesia or standing under sedation and local anesthetic. However, the horse will require a lengthy recovery period of five months before being permitted back under the saddle.
Comparing Success of ISLD & Joint Injections to Treat Kissing Spines
A study by Coomer, et al. performed in the UK completed a study of 75 horses comparing the effectiveness ISLD surgery to joint injections for treating kissing spines. The study concluded that horses treated with ISLD are “24 times more likely to experience long-term resolution of signs of back pain” than horses treated medically with injections (See Fig 1 below). Unlike those treated with injections, radiographs of the ISLD horses showed marked improvement in the space between the dorsal spinous processes.
ISLD Recovery & Rehab Time Table:
(Note: This time table is to be used for reference purposes only. Your surgeon will provide you with a rehabilitation protocol that is appropriate for your horse’s optimal recovery.)
- Weeks 1-3: Hand walk 30 minutes a day, twice a day
- Week 4: Turnout in SMALL paddock, 10 minutes of lunging with saddle on
- Week 5: Turnout in SMALL paddock, 20 minutes of lunging with saddle on
- Week 6: Turnout in SMALL paddock, 30 minutes of lunging with saddle on
- Week 7: Normal turn out, return to working under saddle
Cost & Time Effect of ISLD
While all methods of treatment have their merits ISLD’s benefits are substantial and sustainable in the following ways:
- The minimally invasive nature of this surgery makes it less expensive than other surgical methods.
- Long term relief is achievable. Pain associated with kissing spines was relieved for up to three years in 95% of the horses available for follow up in Dr. Coomer’s study using this technique. (Horses were only followed for 3 years so relief can be longer)
Long-Term Prognosis: EXCELLENT
According to Dr. Coomer ‘s published paper A Controlled Study Evaluating a Novel Surgical Treatment of Kissing Spines in Standing Sedated Horses, combining ISLD surgery “with a controlled exercise program” one can expect a “resolution in kissing spines.”
Fig 1. Dr. Hartman’s patient 6 weeks post-op shows significant space increase between the dorsal spinous processes.
Fig 2: Radiograph of spine prior to surgery.