Comparison of histomorphometric characteristics of dorsal colon and pelvic flexure biopsy specimens obtained from horses with large colon volvulus that underwent resection.

OBJECTIVE: To determine the degree of histomorphometric damage in dorsal colon and pelvic flexure biopsy specimens (DCBSs and PFBSs, respectively) obtained from horses with large colon volvulus (LCV) and assess the accuracy of predicting short-term outcome for those horses on the basis of DCBS or PFBS characteristics. ANIMALS: 18 horses with ≥ 360° LCV that underwent large colon resection. PROCEDURES: During surgery, biopsy specimens from the dorsal colon resection site and the pelvic flexure (when available) were collected from each horse. Interstitial-to-crypt (I:C) ratio (ratio of the lamina propria space occupied by the interstitium to that occupied by crypts), hemorrhage within the lamina propria (mucosal hemorrhage score [MHS] from 0 to 4), and percentage losses of glandular and luminal epithelium were determined in paired biopsy specimens and compared to determine optimal cutoff values for calculating the accuracy of DCBS and PFBS characteristics to predict short-term outcome (survival or nonsurvival after recovery from surgery). RESULTS: Paired biopsy specimens were obtained from 17 of the 18 horses. The I:C ratio and percentage glandular epithelial loss differed between DCBSs and PFBSs. For DCBSs, an I:C ratio ≥ 0.9 and MHS ≥ 3 each predicted patient nonsurvival with 77.8% accuracy. For PFBSs, an I:C ratio ≥ I and MHS ≥ 3 predicted patient nonsurvival with 70.6% and 82.4% accuracy, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Although different, histomorphometric measurements for either DCBSs or PFBSs could be used to accurately predict short-term outcome for horses with LCV that underwent large colon resection, and arguably PFBSs are easier to collect.

Prognostic value of colonic and peripheral venous lactate measurements in horses with large colon volvulus.

OBJECTIVE: To determine the prognostic value of (1) colonic venous lactate or peripheral lactate values obtained before and after manual correction of a large colon volvulus and (2) a combination of variables including pelvic flexure biopsy. STUDY DESIGN: Prospective clinical study. ANIMALS: Forty adult horses in which large colon volvulus was diagnosed intraoperatively. METHODS: Colonic venous, peripheral venous, and arterial blood samples were collected to measure lactate values before and after manual correction. Mucosal biopsy samples were obtained in cases that underwent enterotomy or colonic resection and anastomosis. Interstitium to crypt (I:C) ratio and hemorrhage scores were measured. Optimal cutoff values were determined by receiver operator curve analysis, and associations between variables and short-term outcome were determined by univariable regression. Short-term survival was defined as horses being discharged from the hospital. P ≤ .05 was considered significant. RESULTS: No association was found between colonic venous lactate values before (P = .011) or after (P = .201) manual correction of large colon volvulus and determination of short-term outcome. Peripheral venous lactate at admission ≥3.2 mmol/L and after manual correction ≥5 mmol/L, arterial lactate postmanual correction ≥3.53 mmol/L, and histomorphometric measurements of mucosal hemorrhage ≥3 and I:C ratio > 1 were associated with poor short-term outcome. CONCLUSION: Peripheral lactate values, histomorphometric measures of I:C ratio, and hemorrhage score provided prognostic information that could help guide recommendations made to owners. CLINICAL SIGNIFICANCE: Peripheral lactate values after manual correction provide important intraoperative diagnostic information to assist in predicting case outcome in the operative and immediately postoperative period.

Improvement in Bilateral Carpal Valgus Deviation in 9 Foals After Unilateral Distolateral Radial Periosteal Transection and Elevation.

OBJECTIVES: To evaluate the effect of periosteal transection and elevation in foals with naturally occurring carpal valgus deviation. STUDY DESIGN: Prospective clinical study. ANIMALS: Foals (n = 9) with bilateral carpal valgus. METHODS: Foals with bilateral carpal valgus had distolateral radial periosteal transection and elevation (PE) including distal ulnar transection on 1 limb. Foals were stall confined until the skin incisions healed, and then allowed free exercise in a small paddock or round pen. Dorsopalmar carpal radiographs were obtained at 14 day intervals to determine the carpal valgus angle (CVA) until it was <5°. RESULTS: All limbs had a reduction in CVA and there was no significant difference in total carpal valgus angular correction or the rate at which the correction occurred between the surgical and control limb. CONCLUSIONS: Unilateral distolateral radial PE had no effect on carpal angulation in 9 foals with naturally occurring bilateral carpal valgus deviation when performed between 19 and 43 days.

Outcome of medial patellar ligament desmoplasty for treatment of intermittent upward fixation of the patella in 24 horses (2005-2012).

This retrospective study provides long-term results of medial patellar ligament (MPL) desmoplasty in horses with intermittent upward fixation of the patella (UFP) that were treated at a single referral hospital over a 7-year period. Follow-up interviews were conducted with owners, trainers, or referring veterinarians using a standardized questionnaire. Overall, 71% of horses returned to their intended use with only 18% at a higher level. Recurrence of UFP was noted in 33% of cases. Satisfaction with the procedure was generally low, with only 50% of owners being completely satisfied. Further investigation is warranted to determine appropriate medical and/or surgical therapy.

Résultat de la desmoplastie du ligament superficiel interne pour le traitement de l'accrochement supérieur intermittent de la rotule chez 24 chevaux (2005­2012). Cette étude rétrospective présente les résultats à long terme de la desmoplastie du ligament superficiel interne (LSI) chez des chevaux atteints d'un accrochement supérieur intermittent de la rotule (ASI) qui ont été traités dans un seul hôpital spécialisé pendant une période de 7 ans. Des entrevues de suivi ont été réalisées auprès des propriétaires, des dresseurs ou des vétérinaires traitants à l'aide d'un questionnaire standardisé. Dans l'ensemble, 71 % des chevaux sont retournés à leur utilisation attitrée et seulement 18 % des chevaux ont réussi à mieux performer. La récurrence de l'ASI a été notée dans 33 % des cas. La satisfaction à l'égard de l'intervention était généralement faible, et seulement 50 % des propriétaires étaient entièrement satisfaits. De nouvelles études sont justifiées afin de déterminer le traitement médical et/ou chirurgical approprié.(Traduit par Isabelle Vallières).

The influence of perfusate volume on antimicrobial concentration in synovial fluid following intravenous regional limb perfusion in the standing horse.

This study investigated the influence of perfusate volume on antimicrobial concentration in synovial fluid following intravenous regional limb perfusion (IVRLP) and assessed the efficacy of low volume IVRLP. The front limbs of 9 horses were randomly assigned to 1 of 3 volume groups: 10 mL (Group 1), 30 mL (Group 2), or 60 mL (Group 3). A tourniquet was applied distal to the carpus and the limbs were perfused with 500 mg genta-micin diluted to the assigned volume via a catheter placed in the lateral palmar digital vein at the level of the proximal sesamoid bones. Synovial fluid samples were collected from the metacarpophalangeal joint at 30 minutes, followed by removal of the tourniquet. Gentamicin concentration in synovial fluid was detected using a fluorescence polarization immunoassay. There were no statistically significant differences among gentamicin concentrations in synovial fluid among perfusate volume groups. Mean gentamicin concentration in Group 1 (125.9 µg/mL) was higher than Group 2 (82.7 µg/mL) and Group 3 (56.1 µg/mL).

Influence du volume perfusé sur la concentration antimicrobienne dans le liquide synovial après la perfusion intraveineuse régionale d'un membre chez un cheval debout. Cette étude a étudié l'influence du volume perfusé sur la concentration antimicrobienne dans le liquide synovial après la perfusion intraveineuse régionale d'un membre (PIRM) et a évalué l'efficacité d'un faible volume de PIRM. Les membres antérieurs de 9 chevaux ont été assignés au hasard à 1 de 3 groupes de volume: 10 ml (Groupe 1), 30 ml (Groupe 2) ou 60 ml (Groupe 3). Un tourniquet a été appliqué en aval du carpe et les membres ont été perfusés avec 500 mg de gentamicine diluée au volume assigné par un cathéter placé dans la veine digitale palmaire latérale au niveau des os sésamoïdes proximaux. Les échantillons de liquide synovial ont été prélevés de l'articulation métacarpo-phalangienne à 30 minutes, suivis de l'enlèvement du tourniquet. La concentration de gentamicine dans le liquide synovial a été détectée à l'aide d'un immuno-essai par fluorescence polarisée. Il n'y avait pas de différences statistiquement significatives entre les concentrations de gentamicine dans le liquide synovial parmi les groupes de volume perfusé. La concentration médiane de gentamicine du Groupe 1 (125,9 µg/ml) était supérieure à celle du Groupe 2 (82,7 µg/ml) et du Groupe 3 (56,1 µg/ml).(Traduit par Isabelle Vallières).

Tenosynoviotomy for sepsis of the digital flexor tendon sheath in 9 horses.

OBJECTIVE: To describe a tenosynoviotomy technique for treatment of sepsis of the digital flexor tendon sheath (DFTS) in horses and report long-term outcome. STUDY DESIGN: Case series. ANIMALS: Horses (n = 9). METHODS: Horses were positioned in lateral recumbency with the affected limb uppermost. A linear incision was made just lateral to the mesotenon beginning 5 cm proximal to the apices of the proximal sesamoid bones, extending 2 cm distal to the bifurcation of the superficial digital flexor tendon (SDFT). The incision was continued through the skin, subcutaneous tissue, palmar/plantar annular ligament, and DFTS. Tenotomy of the distal lateral branch of the SDFT was also performed. The site was thoroughly debrided, lavaged, and packed with gauze and allowed to heal by second intention. Follow-up was obtained via owner telephone interview. RESULTS: Mean surgery time was 32 minutes (range, 10-64 minutes). Systemic antibiotics were administered postoperatively (range, 11-46 days; mean, 23 days). Mean hospitalization was 11 days (range, 0-49 days). Follow-up was available for 7 (70%) horses. One year postoperatively, 5 (71%) horses were serviceable for their intended use, and 2 (29%) had been euthanatized. Of 5 survivors, 3 returned to ridden exercise, 1 was retired as a broodmare, and 1 was a broodmare. All owners were satisfied with the cosmetic appearance of the surgery site. CONCLUSION: Open drainage via tenosynoviotomy, performed as a salvage procedure, represents a feasible treatment for DFTS sepsis.

Use of a suprapatellar pouch portal and laparoscopic cannula for removal of debris or loose fragments following arthroscopy of the femoropatellar joint of 168 horses (245 joints).

OBJECTIVE: To validate the safety of a suprapatellar pouch (SPP), approach to the femoropatellar joint (FPJ), and describe use of a laparoscopic cannula to remove debris or loose bodies. STUDY DESIGN: Retrospective case series ANIMALS: Horses (n = 168) with osteochondritis dissecans (OCD) of the FPJ. METHODS: Arthroscopy was performed on 245 FPJ with OCD. Two subpatellar portals were created, 1 axial and 1 abaxial to the lateral patellar ligament. Additionally, a SPP egress portal for lavage, was created 2 cm proximal to the most palpable dorsolateral eminence of the patellar base. A 10-mm laparoscopic cannula and trocar unit was used in all SPP portals. The SPP portal was closed in 2 layers in the first 121 horses and the skin only in the remaining 47 horses. Medical records were reviewed for complications and surgical time and owner satisfaction with cosmesis obtained. RESULTS: No complications were recorded for the SPP portal regardless of closure technique. All owners were satisfied with the cosmetic outcome of the procedure once the hair had grown back and felt the additional incision did not negatively impact horses presented for sale at public auction. Mean surgery time was 27.7 min/joint. CONCLUSION: No complications were recorded using a SPP portal and laparoscopic cannula, and owner satisfaction was high.

Survival and complications after large colon resection and end-to-end anastomosis for strangulating large colon volvulus in seventy-three horses.

OBJECTIVE: To report complications and survival after large colon resection and end-to-end anastomosis in horses with strangulating large colon volvulus. STUDY DESIGN: Retrospective case series. ANIMALS: Horses (n=73) with strangulating large colon volvulus. METHODS: Records (January 1995 to December 2005) of horses that had large colon resection and anastomosis for strangulating large colon volvulus were reviewed for complications. Follow-up data were obtained by telephone questionnaire at least 1 year postoperatively. Cox proportional hazards model was used for multivariate association with survival time. Variables included admission date, age, temperature, heart rate, packed cell volume, total plasma protein concentration, white blood cell count, breed, and sex. Significance was set at P<.05. RESULTS: The most common postoperative complication was diarrhea. None of the 9 variables of interest were significant for survival. Short-term survival rate (to discharge) was 74%. Overall survival rates at 1, 2, and 3 years postoperatively were 67.8%, 66.0%, and 63.5%, respectively. Four horses died of colic in the first year after surgery. All horses surviving long-term (>1 year) returned to their intended use (37 brood mares, 2 racehorses, and 1 show horse) with no chronic problems related to the surgical procedure. CONCLUSION: None of the variables examined were associated with survival. Outcomes were similar to other large studies of surgical colic in the horse. Self-limiting diarrhea is common after large colon resection and the prognosis for survival after hospital discharge is favorable. CLINICAL RELEVANCE: Horses that survive the early postoperative period and are discharged after large colon resection and anastomosis have a good chance for long-term survival with minimal negative impact on quality of life and use.

Fertility and complications after fetotomy in 20 brood mares (2001-2006).

OBJECTIVE: To report fertility (foals conceived, live foal births) of mares after partial fetotomy to resolve dystocia and complications associated with fetotomy. STUDY DESIGN: Retrospective study. ANIMALS: Horses (n=20). METHODS: Medical records (2001-2006) of mares that had partial fetotomy (1-3 cuts) for dystocia were reviewed. Complications and subsequent fertility were obtained by interview and live foal data were recorded by the Jockey Club. Postfetotomy conception and live foals produced over 21 breeding seasons (defined as years each mare was bred regardless of conception) were recorded. RESULTS: Twenty mares were identified. Bilateral carpal flexion alone (3 mares) or in combination with another deformity (7 mares) was the most common presentation for dystocia. From 2001 to 2006, there were 24 breeding seasons for which 20 mares conceived (83%). Eighteen mares conceived before 2006 and all produced live foals. Three mares were bred in 2006; 2 became pregnant, 1 was electively aborted, and 1 is pregnant. Eight of 19 (42%) mares had retained placenta, which were expelled within 24 hours after medical therapy. CONCLUSION: Partial fetotomy performed with 1-3 cuts does not impede a successful reproductive future. CLINICAL RELEVANCE: In selected equine dystocia cases, partial fetotomy should be given primary consideration when the foal is dead and vaginal delivery cannot be readily achieved. Fetotomy should not adversely affect the future fertility of the mare.

Use of colonic luminal pressure to predict outcome after surgical treatment of strangulating large colon volvulus in horses.

OBJECTIVE: To evaluate the relationship of colonic luminal pressure (CLP) measurements to outcome in horses with large colon volvulus (LCV) after either manual correction or large colon resection and anastomosis (LCRA). STUDY DESIGN: Retrospective study. ANIMALS: Horses (n=57) that had LCV. METHODS: Records for horses with LCV (March 1997-December 2003) were reviewed. Inclusion criteria were strangulating LCV proximal to the cecocolic ligament (>270 degrees), recorded CLP, and successful recovery from anesthesia. CLP measurements and survival/mortality rates were compared between horses that had manual correction (M) or LCRA (R). RESULTS: Of 57 horses, 27 had M and 30 had LCRA. For group M, CLP measurements had a sensitivity of 0.60 and specificity of 0.77 for predicting survival, whereas for group R, sensitivity was 0.50 and specificity was 0.54. CONCLUSION: In our LCV population, elevated CLP measurements had poor accuracy for predicting outcome in horses after surgical correction, especially after LCRA. CLINICAL RELEVANCE: CLP measurements based on a single hospital population of horses with LCV should be used with caution for other hospital populations of LCV. CLP may be only one of many variables needed for predicting outcome of horses with strangulating LCV, especially after LCRA.

Efficacy of omeprazole paste for prevention of recurrence of gastric ulcers in horses in race training.

OBJECTIVE: To determine whether omeprazole oral paste administered at a dosage of 0.5 or 1 mg/kg (0.23 or 0.45 mg/lb), PO, every 24 hours would effectively prevent the recurrence of gastric ulcers in horses in race training. DESIGN: Prospective study. ANIMALS: 135 horses. PROCEDURES: Horses with gastric ulcers were treated with omeprazole at a dosage of 4 mg/kg (1.8 mg/lb), PO, every 24 hours for 28 days. Horses in the dose selection portion of the study were sham dose treated or received 0.5 or 1 mg of omeprazole/kg, PO, every 24 hours for an additional 28 days. Horses in the dose confirmation portion of the study were sham dose treated or received 1 mg of omeprazole/kg, PO, every 24 hours for an additional 28 days. Gastric ulcers were scored before and after the preventive phase of the study (day 28 to day 56) via gastroscopy, and ulcer scores were compared. RESULTS: Sham-dose-treated horses and horses receiving 0.5 mg of omeprazole/kg had significantly higher ulcer scores than did horses receiving 1 mg of omeprazole/kg. There was a significant difference between the proportion of horses receiving 1 mg of omeprazole/kg (38/48 179%]) that remained ulcer free and the proportion of sham-dose-treated horses (7/44 [16%]) that remained ulcer free. CONCLUSIONS AND CLINICAL RELEVANCE: Omeprazole oral paste administered at a dosage of 1 mg/kg, PO, every 24 hours for 28 days was effective for prevention of recurrence of gastric ulcers in horses in race training.

Severe diaphragmatic necrosis in 4 horses with degenerative myopathy.

Severe diaphragmatic necrosis occurred in horses with degenerative myopathy due to polysaccharide storage myopathy (n = 2), nutritional myopathy (n = 1), and vasculitis (n = 1). Blood gas analysis performed in 1 horse indicated development of respiratory acidosis. Respiratory muscle necrosis can be severe in horses with degenerative myopathy and can lead to respiratory failure.