One of the most popular sessions at each American Association of Equine Practitioners’ (AAEP) convention is the Kester News Hour, which features three renowned veterinarians sharing their picks for the top studies of the previous year in three research areas: equine medicine, reproduction, and surgery.
This year, Elizabeth Santschi, DVM, Dipl. ACVS, a professor of equine surgery at the Kansas State University College of Veterinary Medicine, in Manhattan, shared her top take-home messages for equine surgery-related studies of 2016 during the AAEP convention, held Dec. 4-7 in Orlando, Florida.
Radial Fracture Outcomes
Researchers behind the first study Santschi described sought to determine survival-to-discharge rates for horses with radial fractures and examine risk factors affecting survival to discharge in conservatively and surgically managed fractures. The radius is the large leg bone located above the horse’s knee (or carpal joint).
The team included 54 horses in the retrospective study, 13 of which were euthanized at admission due to fracture severity or owner financial constraints. Of the remaining 41 horses, 14 had incomplete fractures and were managed conservatively with Robert-Jones bandages and splints; 12 survived to discharge. The other 27 horses had complete fractures that were repaired surgically; 15 of those horses survived to discharge.
Santschi said both conservatively managed horses that were euthanized developed support-limb laminitis. Of the surgical horses that did not survive, two were euthanized following recovery from anesthesia, 11 developed surgical site infections (and these were closely associated with open fractures), and eight suffered failure of the surgical repair.
Risk factors tied to surgical failure were age (older horses were less likely to survive than younger horses), surgical duration (procedures that took more than 168 minutes—nearly three hours—were less likely to have a successful outcome), and surgical site infection (which trended toward a decreased survival rate).
Santschi’s take-home message: Younger horses and older horses with incomplete fractures tend to have a good prognosis for recovery. Also, horses with open fractures are more likely to develop surgical site infection, which is associated with a poor prognosis for survival.
Stewart S, Richardson D, Boston R, et al. Risk factors associated with survival to hospital discharge of 54 horses with fractures of the radius. Vet Surg 2015;44:1036-1041.
Long-Term Outcomes of Upward Fixation of the Patella Treatment
Next, Santschi described a study in which researchers evaluated the long-term outcome of a procedure called medial patellar ligament splitting to treat upward fixation of the patella (UFP). During the procedure, a surgeon inserts a blade or needle (sometimes guided by ultrasound) through the skin to split the proximal (inner) third part of the medial patellar ligament.
The study authors looked at the medical records of 85 horses that underwent the ligament splitting procedure, 83 (97.6%) of which showed complete UFP resolution immediately after or within two weeks of surgery. Santschi said UFP persisted in the remaining two horses (2.4%), even after the procedure was repeated.
The team collected follow-up data on 78 horses (90.5%) 3 to 14 years after surgery. None of those horses experienced complications, and no recurrence of UFP was reported in horses that returned to work after surgery.
Santschi summed up that the ligament splitting procedure was highly effective, had a low complication rate, and offered a rapid return to function for horses with UFP.
Anderson C, Tnibar A. Medial patellar ligament splitting in horses with upward fixation of the patella: A long-term follow-up. Equine Vet J 2016;48:312-314.
Comparing Joint Lavage Techniques
It’s never good when debris winds up inside your horse’s body, but it can be especially problematic—even career-threatening—if it ends up in a joint and becomes infected. When debris does end up in a joint, veterinarians use a joint lavage to clean as many contaminants out of the structure as possible.
The researchers that completed the next study Santschi described evaluated different lavage techniques to see which was most effective in removing 1.5 million tiny microspheres from a cadaver horse’s tarsocrural joints (between the tibia and the talus in the upper hock joint). Joints were lavaged with saline via an arthroscope or three 14-gauge needles, each placed in a different position.
Santschi said the team found that the 14-gauge needles lavaged 2.5 times more microspheres from joints than did the single arthroscope. But, regardless of which technique the researchers used, about 80% of the microspheres were removed from the joint with the first liter of lavage fluid.
Her take-home message for veterinarians: It’s better to place more smaller needles than one large one when lavaging joints, and one to two liters of lavage fluid is probably sufficient to remove most of the debris.
Loftin P, Beard W, Guyan M, et al. Comparison of arthroscopic and needle lavage and lavage volume on the recovery of colored microspheres from the tarsocrural joints of cadaver horses. Vet Surg 2016;45:240-245.
Conservative Lower Jaw Fracture Management
Next, Santschi described a retrospective study in which researchers evaluated the outcome of conservative management (no surgery) of unilateral mandibular (lower jaw) fractures in horses. The outcome was considered successful if horses returned to their normal use, chewed normally, and had no additional fracture-related problems.
The team included 24 horses, aged 1 to 24 years. Sixty-seven percent of fractures occurred on the right side of the jaw, 33% occurred on the left, and 62% involved horses’ teeth. Additionally, 67% of fractures were open when horses presented to veterinarians.
Santschi said 23 horses (96%) had a successful outcome. One horse (4%) had chronic tooth loosening, feed impaction, and chewing problems and was euthanized five years following conservative treatment.
The bottom line, she said: Most horses with one-sided mandibular fractures managed conservatively will do well following treatment.
Jansson N. Conservative management of unilateral mandibular fractures in horses. Vet Surg 2016;45:1063-1065.
Triamcinolone Joint Injections With and Without HA Compared
Does adding hyaluronic acid (HA) to triamcinolone (TA) joint injections improve the outcome? That’s what the researchers behind Santschi’s next study sought to determine.
They collected and evaluated data on 80 horses treated with either TA alone or TA + HA at 13 clinics with an average lameness score of 2 (on a scale of 1 to 5). Success was defined as two-point reduction in lameness score.
Three weeks after injection, treatments in 87.8% of horses that received TA alone were considered successful, compared to 64.1% of treatments that received TA + HA. After three months, however, there was no difference between the groups, with about 50% of horses from each returning to their previous level of work.
Santschi’s take-home: TA alone appeared to offer quicker results, but ultimately, both treatments had similar long-term success rates.
De Grauw J, Visser-Meijer M, Lasjley F, et al. Intra-articular treatment with triamcinolone compared with triamcinolone with hyaluronate: A randomized multicenter clinical trial. Equine Vet J 2016;48:152-158.
Sarcoid Treatments Compared
Next, Santschi described a retrospective study in which researchers compared several sarcoid treatments applied to 230 equids (including six donkeys) with 614 sarcoids.
The treatment depended on the type of sarcoid and its location, Santschi said, and included surgical excision, topical treatment with imiquimod or acyclovir, cryosurgery, local chemotherapy with cisplatin or carboplatin, and bacillus Calmette-Guerin (BCG) vaccine injection. Follow-up was conducted six months after the patient’s last treatment.
Overall, Santschi said, 74.9% of treatments were considered successful. She said treatment failure was more common when multiple sarcoids were present, and success was more likely when immunostimulation (i.e., a BCG vaccine) was administered in conjunction with another treatment.
Treatment complications included wound dehiscence, skin irritation, and abscess formation, though no complications were noted with cryosurgery, acyclovir administration, or local chemo, she added.
Both Santschi and the study authors cautioned that there was selection bias in this study—essentially, specific types of sarcoids in certain locations were treated with certain procedures. But, the study authors said the results could still help clinicians select treatments and determine prognosis for equids with sarcoids treated with the procedures highlighted in their article.
Haspeslagh M, Vlaminck L, Martens A. Treatment of sarcoids in equids: 230 cases (2008–2013). J Am Vet Med Assoc 2016;249:311-318.
Treating Nose Bleeds due to Guttural Pouch Mycosis
The final study Santschi described sought to evaluate carotid artery ligation coupled with topical treatment for epistaxis (nose bleed) resulting from guttural pouch mycosis, a potentially fatal fungal infection in the guttural pouch.
A little background: The guttural pouch is full of vital structures (the nerves that control swallowing and the carotid artery). And, in some cases, the fungal infection involves the carotid artery as well as the guttural pouch. As such, evidence of bleeding from one or both nostrils should be treated as an emergency, as horses can hemorrhage and bleed out. One surgical treatment—the one tested in this study—involves, essentially, tying-off the carotid artery to prevent blood loss.
Santschi said the researchers carried out the procedure in 24 horses that were an average of 7.4 years old. In addition to ligation, veterinarians applied topical treatments in 16 horses and removed fungal plaques in the guttural pouch in eight. It took an average of six topical treatments to resolve lesions in the guttural pouch.
Epistaxis recurred in five horses (20.8%), four of which died as a result. Additionally, two horses died after surgery due to colic or pleuropneumonia.
Ultimately, Santschi said, ligation did not provide as successful results as coil embolization (a procedure that involves catheterizing the carotid artery and placing tiny coils in the artery to prevent bleeding), but is less technically demanding for the veterinarian. The study authors said this procedure could serve as “a salvage procedure when financial or technical constraints prevent the use” of more advanced treatments.