Dr. Scott E. Palmer

Aitken MR, Parente EJ. Epiglottic abnormalities in mature nonracehorses: 23 cases (1990-2009). J Am Vet Med Assoc 2011;238(12):1634-1838.

Take Home Message: Coughing is a common complaint in mature non-racehorses with epiglottic abnormalities.  Upper airway endoscopy is recommended in the evaluation of older horses with a cough.  Surgical treatment can be beneficial in most horses with some requiring further postoperative medical treatment.

Allen KJ, Franklin SH. Assessment of the exercise tests used during overground endoscopy in UK Thoroughbred racehorses and how these may affect the diagnosis of dynamic upper respiratory tract obstructions. Equine Vet J Suppl 2010;42(38):587-591.

Take Home Message: A principle advantage of dynamic videoendoscopy is the ability to evaluate the horse in its natural surroundings and under race conditions. However, it may be difficult to standardize exercise tests in the field under widely varying conditions.  It is best to replicate race conditions as closely as possible.

Davidson EJ, Martin BB, Rieger RH, et al. Exercising videoendoscopic evaluation of 45 horses with respiratory noise and/or poor performance after laryngoplasty. Vet Surg 2010;39(8):942-948.

Take Home Message: There was no relationship between collapse of the left arytenoid cartilage and grade 3 or 4 postsurgical abduction but was likely in horses with no abduction.  Complex obstructions causing respiratory noise were observed in most examinations but were not specific for arytenoid collapse.  Common observations included dynamic collapse of the right vocal fold, billowing of the left vocal fold (if not removed at the time of surgery), dynamic collapse of the aryepiglottic folds or the corniculate process of the left arytenoid cartilage, dorsal displacement of the soft palate and pharyngeal collapse.  While some of these conditions may be diagnosed with a resting endoscopic examination, this data underscores the value of performing a dynamic examination prior to surgery.

Garrett KS, Woodie JB, Embertson RM. Association of treadmill upper airway endoscopic evaluation with results of ultrasonography and resting upper airway endoscopic evaluation. Equine Vet J 2011;43(3):365-371.

Take Home Message: Ultrasonography is a valuable addition to the diagnostic evaluation of abnormal arytenoid movement and may be extremely valuable for case selection, particularly in an effort to make a differential diagnosis between early chondritis and laryngeal hemiplegia.

Dixon PM, et al. Equine paranasal sinus disease: A long-term study of 200 cases (1997-2009): Treatments and long-term results. Equine Vet J 2011.

Take Home Message: More conservative treatments, including removal of intrasinus inspissated pus by sinoscopy, pre-existing sinonasal fistula or sinusotomy, are effective for chronic primary sinus disease in many cases.  Standing sinusotomy, mainly using a small maxillary site, was suitable for most cases of sinus disease in mature horses.  Not all horses with sinus disease require treatment with a flap procedure under general anesthesia.

Surgery Therapeutics

Alkabes SB, Adams SB, Moore GE, et al. Comparison of two tourniquets and determination of amikacin sulfate concentrations after metacarpophalangeal joint lavage performed simultaneously with intravenous regional limb perfusion in horses. Am J Vet Res 2011;72(5):613-619.

Take Home Message: In standing horses, IV regional limb perfusion performed simultaneously with joint lavage resulted in negligible loss of amikacin in the egress lavage fluids.  The Esmarch tourniquet was more effective in preventing loss of amikacin from the distal portion of the limb, easier to use, and less expensive than the pneumatic tourniquet.

Kasashima Y, Ueno T, Tomita A, Goodship AE, Smith RKW. Optimisation of bone marrow aspiration from the equine sternum for the safe recovery of mesenchymal stem cells. Equine Vet J 2011;43(3):288-294.

Take Home Message: Accurate placement of a Jamshidi needle into the medullary cavity of the 4^th to 6^th sternebrae is facilitated by use of ultrasonography and enables aspiration of bone marrow reliably with minimal damage to the sternum and risk to the horse.

Adams MK et al. Equine bone marrow-derived mesenchymal stem cells: Comparing the sternum and the ilium. In Proceedings, Am Coll Vet Surg Symposium 2011.

Take Home Message: Both the sternum and the ilium offer a rich supply of stem cells that have similar growth rate characteristics. The nucleated cell counts were significantly higher in the first 5 ml aspirate from both the sternum and the ilium than in the second 5 ml aspirate.

Goodwin EE, Young NJ, Dudhia J, et al. Implantation of bone marrow-derived mesenchymal stem cells demonstrates improved outcome in horses with overstrain injury of the superficial digital flexor tendon. Equine Vet J 2011;43(3) ….-….

Take Home Message: this study shows that marrow-derived mesenchymal stem cell implantation is safe and appears to reduce re-injury rate after superficial digital flexor injury, especially in National Hunt racehorses.  It is the first report that provides evidence for long term efficacy of mesenchymal stem cell treatment for tendinopathy in racehorses. However, the long term success in the Thoroughbred flat horse remains a challenge.

Schramme MC, et al. The effect of intralesional bone marrow derived mesenchymal stem cells and bone marrow supernatant on collagen fibril size in a surgical model of equine superficial digital tendonitis. In Proceedings, Am Coll Vet Surg Symposium 2011.

Take Home Message: The matrix of normal, uninjured SDFT tendon consists of populations of small and large diameter collagen fibrils.  Injured tendon healed with a prominence of small diameter fibrils, regardless of whether lesions were treated with bone marrow-derived mesenchymal stem cells at 4 weeks.

Becerra P, et al. In vivo tracking of injected mesenchymal stem cells using Technetium-99m. In Proceedings, Am Coll Vet Surg Symposium 2011.

Take Home Message: Highest cell numbers were retained in the damaged area of the tendon after intra-lesional injection (approximately 10% of cells were still present in the tendon after 24 hrs).  Regional perfusion was a viable alternative if no core lesion is present.  No detectable cells were found in the damaged area of tendon following intravenous injection of stem cells.

Bohannon L, et al. The effects of mixing pharmaceuticals with equine stem cells prior to treatment of orthopedic injuries in the horse. In Proceedings, Am Coll Vet Surg Symposium 2011.

Take Home Message: Incubation of MSCs with hyaluronic acid and penicillin/streptomycin resulted in susteained MSC viability of 80%.  Aminoglycoside antibiotics (Gentamicin and Amikacin) are toxic to equine bone marrow-derived mesenchymal stem cells.  Aminoglycoside antibiotics  should not be mixed with MSCs prior to injection.

Bischofberger AS, et al. The effect of short and longer-term treatment with manuka honey gel on second intention healing of wounds contaminated with feces and non-contaminated wounds on the distal aspect of equine forelimbs. In Proceedings, Am Coll Vet Surg Symposium 2011.

Take Home Message: There was no effect of manuka honey gel on healing of contaminated wounds.  Wounds treated with manuka honey gel throughout the healing period healed faster than did all other wounds.

Colic

Scantlebury CE, Archer DC, Proudman CJ, et al. Recurrent colic in the horse: Incidence and risk factors for recurrence in the general practice population.  In Proceedings, Colic Research Symposium 2011. 

Take Home Message: The incidence of recurrence of colic in horses following a medical episode of colic was high in this population (36.5%).  Horses with a known dental problem or cribbing were at increased risk of recurrence.  Comment: This confirms long-held beliefs and gives us a baseline number to share with clients when treating medical colics in the field.

Burford JH, Tudur-Smith C, Smith J, et al. The incidence of post-operative colic in 1412 horses discharged following exploratory laparotomy for investigation of acute gastrointestinal disease.  In Proceedings, Colic Research Symposium 2011;126.

Take Home Message: The prevalence of subsequent episodes of colic in horses undergoing exploratory surgery may be higher than previously estimated.  The incidence of colic in this large population of horses following exploratory laparotomy (54.4%) is far greater than the estimated rate within the general equine population. 

Peloso JG, Cohen N. Using serial peritoneal lactate in referred horses with signs of colic to identify strangulating intestinal lesions.  In Proceedings, Colic Research Symposium 2011;105.

Take Home Message: Use of a point-of-care lactate measurement showed that a positive increase in lactate concentration of peritoneal fluid over a 30 min period was significantly associated with presence of a strangulating bowel lesion.  Sensitivity of this procedure was 79% and specificity was 88%. 

Ness SL, et al. Ultrasonic visualization of colonic mesenteric vasculature as an indicator of larg colon right dorsal displacement and/or 180 degree vovulus in horses. In Proceedings, Colic Research Symposium 2011;128.

Take Home Message: Ultrasonic visualization of colonic mesenteric vasculature adjacent to the right body wall was found to be highly specific and sensitive for the detection of right dorsal colon dorsal displacement and/or 180 degree colon volvulus in horses. 

Racing Injuries

Powell SE. Low-field standing magnetic resonance imaging findings of the metacarpo/metatarsophalangeal joint of racing Thoroughbreds with lameness localized to the region: A retrospective study of 131 horses. Equine Vet J 2011.

Take Home Message: 35.8% of horses with lameness localized to the fetlock region had MRI findings consistent with fracture pathology that was not evident radiographically.

Trope GD, Anderson GA, Whiton RC. Patterns of scintigraphic uptake in the fetlock joint of Thoroughbred racehorses and the effect of increased radiopharmaceutical uptake in the distal metacarpal/tarsal condyle on performance. Equine Vet J 2011;43(5):509-515.

Take Home Message: Overload of the MC/MT condyles is a common and significant problem of Thoroughbred racehorses that is readily identified with scintigraphy.  Scintigraphy is less useful for screening for potential condylar fractures in horses that are lame or performing poorly.

Tull T, Bramlage LR. Racing prognosis after cumulative stress-induced injury of the distal portion of the third metacarpal and third metatarsal bones in Thoroughbred racehorses: 55 cases (2000-2009). J Am Vet Med Assoc 2010;238(10):1316-1322.

Take Home Message: Thoroughbred racehorses with cumulative stress-induced bone injury of the distal portion of MC/MT3 treated with free-choice exercise have a favorable prognosis with no appreciable decrease in class or performance.  However, horses with semilunar articular fractures had a reduced prognosis for racing.