Use of rotational periosteal flaps in primary repair of sinofacial fractures in seven horses.

Case history: Medical records were reviewed of horses (n = 7) undergoing surgery for fracture of one or more facial bones extending into the paranasal sinuses that was repaired primarily within 24 hours of the time of injury using a rotational periosteal flap, between April 2009 and May 2017. A kick from another horse was the cause of the injury of three horses, and one horse was injured when it collided with a tree. The cause of the injury of three horses was unknown.Clinical findings and treatment: Fractures were of the right maxillary bone in two horses, the left maxillary bone in two horses, the left frontal and left nasal bones in two horses, and the right frontal bones in one horse. The fracture of all but one horse was accompanied by an open wound. The fracture of all seven horses was reduced, stabilised, and covered with a rotational, periosteal flap. Surgery was carried out while standing in six horses, and while anesthetised in one horse. All horses had a deficit in the fractured facial bones after the fracture was reduced. Four horses had complications following surgery, but all horses were reported to have excellent cosmetic outcomes and had retuned to their previous level of activity, as reported by their owners.Clinical relevance: Covering a primarily repaired sinofacial fracture of a horse with a rotational periosteal flap resulted in good cosmetic outcomes, and may be especially beneficial if the fracture is accompanied by loss of bone.

Evaluation of the pharmacokinetics of imipenem following regional limb perfusion using the saphenous and the cephalic veins in standing horses.

This prospective experimental study goal was to determine the pharmacokinetics of imipenem after intravenous regional limb perfusion (IV-RLP) in standing horses. Nine horses participated in the study; that was approved by the University Animal Care and Use Committee. One thoracic limb or one pelvic limb of each horse was randomly selected. After the veins were catheterized, an Esmarch bandage tourniquet was applied and the catheter was injected with a solution containing 500mg of imipenem. Synovial fluid samples were collected from the fetlock joint and blood samples were collected from the jugular vein. All samples were analyzed for imipenem concentration using liquid chromatography mass spectrometry. Cmax of imipenem in the fetlock joint using the cephalic and the saphenous vein was 87 and 60µg/mL, respectively. The results indicate that by performing IV-RLP using the cephalic/saphenous, one can achieve imipenem concentrations in the fetlock joint that are well above the MIC of most susceptible pathogens including resistant bacteria such as Methicillin Resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. Thus, with selective; judicious use, RLP with imipenem can markedly increase treatment efficacy of severe distal limb infections in horses.

Evaluation of regional limb perfusion with chloramphenicol using the saphenous or cephalic vein in standing horses.

Regional limb perfusion (RLP) significantly decreases morbidity and mortality associated with distal limb injuries in horses. There is an urgent need for finding additional effective antimicrobial drugs for use in RLP. In this study, we tested the pharmacokinetics (PK) of chloramphenicol in RLP. Eight horses participated in the study, which was approved by the University Animal Care and Use Committee. The cephalic and the saphenous veins were used to perfuse the limbs. Synovial samples were collected from the metacarpo/metatarsophalangeal (MCP/MTP) joint. The Friedman Test was applied for assessing change in PK concentration over time, for all time points. The Wilcoxon Signed Ranks Test was used to test the difference between PK concentration in joint & serum as well as concentration in joint vs. MIC. The comparison of measurements between measurements taken on hind vs. front legs was carried out using the Mann-Whitney Test. A P-value of 5% or less was considered statistically significant. After RLP, the concentration of chloramphenicol in the synovial fluid of the MCP/MTP joint using either the cephalic or the saphenous vein was initially far above the minimal inhibitory concentration (MIC) of most susceptible pathogens and remained above the MIC for approximately 6 h. The results indicate that performing RLP using the cephalic and saphenous veins enables reaching concentrations of chloramphenicol in the MCP/MTP joint that are well above the MIC of most susceptible pathogens. The chloramphenicol concentrations achieved in the synovial fluid of the MCP/MTP joint in the current study were between 1.5 (MTP) and 7 (MCP) times the MIC of MRSA in horses. These results are encouraging since MRSA infections are becoming far more common, causing considerable morbidity. To the best of our knowledge, this is the first study to evaluate the pharmacokinetics of chloramphenicol following RLP in the horse and the results are positive.

Surgical treatment for acute small intestinal obstruction caused by Parascaris equorum infection in 15 horses (2002-2011).

REASONS FOR PERFORMING STUDY: There is a consensus in the veterinary literature that Parascaris equorum (ascarid) impaction carries a poor prognosis. Hence surgery is often delayed and foals are often subjected to euthanasia after diagnosis of ascarid impaction is established. Our clinical impression was that ascarid impaction carries a better prognosis than previously reported. OBJECTIVES: Our expectation was that manually evacuating the impaction into the caecum, thus refraining from opening the small intestine, would improve the prognosis for survival of horses with ascarid impaction. The aim of this study was to examine medical records of horses treated surgically for ascarid impaction, record their clinical findings and evaluate the association of outcome with the method of relieving the impaction. METHODS: The medical records of all horses presented to our hospital between October 2002 and December 2011 that underwent exploratory celiotomy for ascarid impaction were reviewed. Information retrieved from the medical record included surgical findings, surgical technique, complications, short- and long-term survival. The association between categorical variables was assessed using the Fisher's exact test. A P value < 0.05 was considered statistically significant. RESULTS: Fifteen horses fulfilled the inclusion criteria. Eighty percent of horses (12/15) survived to discharge and 60% (6/10) survived for at least one year. Five horses are doing well but are still in convalescence. Horses that underwent small intestinal enterotomy or resection and anastomosis (n = 5) were less likely to survive to discharge (P = 0.022). CONCLUSIONS: In our study, manual evacuation of ascarid impaction into the caecum, while refraining from opening the small intestine resulted in significantly improved survival in horses with ascarid impaction. POTENTIAL RELEVANCE: Refraining from opening the small intestine may be the key to improving surgical outcome in horses with ascarid impaction.