QUESTION: Why might it be helpful to “blister” a bowed tendon or other soft tissue injury? Are there types of injuries you shouldn't blister?
DR. S. HEATH SOIGNIER: Different types of “blisters” are used for a “bowed” tendon. The most common involves the placement of a chemical irritant over the injured area of a distal limb and then placing it under bandage. The thought process behind blistering is that the increased blood flow caused by the blister will lead to a faster rate of healing to a chronic damaged tendon. Another type of counter irritation similar to blistering is “pin firing.” With advancing medicine and treatments, “blistering” is less commonly being used as a treatment for these injuries. The improvement to an injured tendon after blistering is often thought to be a result of the enforced rest in recuperating from the blister and not the actual counter irritation itself.
When people say a horse has a “bowed” tendon, generally they are referring to tearing of the tendon fibers of the superficial or deep digital flexor tendons from the carpus to fetlock of a forelimb or tarsus to fetlock of a hind limb (most commonly the forelimb is affected). When tendon fibers are torn, bleeding in the injured area within the tendon occurs. The acute swelling, heat, and pain the horse experiences can be attributed to this process. The tendon fibers heal with a fibrous scar tissue that is much less elastic than normal tendon fibers. This leaves the injured tendon much more vulnerable to re-injury if not rehabilitated correctly or given the ample amount of time to heal completely.
Icing, cold hosing, and bandaging helps with the initial local inflammatory process. This is most often coupled with nonsteroidal anti-inflammatory drugs, stall rest, and light hand walking within the first few days after the injury occurs. Ultrasonographic diagnosis of these injuries allow veterinarians to develop a treatment plan based on the severity of the injury. These plans could include surgical intervention (i.e. tendon splitting), injections within the tendon lesion (i.e. stem cells, platelet rich plasma, steroids, etc.), and other treatment modalities such as shockwave therapy, laser therapy, and acupuncture. All of the options along with a rehabilitation program, have shown to improve the outcome for these type injuries.
“Blistering” a “bowed” tendon or other soft tissue injury is usually not the appropriate treatment in most cases. Certainly any acutely inflamed tissue should not be blistered. Determining the severity of the injury can dictate the treatment protocol and length of time off for the horse. Oftentimes the best way for these injuries to heal is with careful rehabilitation, a good treatment protocol, and time.
Dr. Heath Soignier graduated from St. George's University School of Veterinary Medicine and completed his Ambulatory Internship with Rood and Riddle in 2013, the same year he joined Rood and Riddle as an associate. Dr. Soignier's special areas of interest include reproduction, neonatal medicine, and dentistry.
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