Effects of intra-articular anesthesia of the tarsometatarsal joint on skin sensation of the distal limb in horses.

Objective: To determine with mechanical nociceptive threshold (MNT) testing whether distal limb skin sensation is affected by intra-articular anesthesia of the tarsometatarsal joint (TMTJ). Animals and procedure: This was a prospective cohort study. Ten client-owned horses that had intra-articular TMTJ anesthesia were included in the study. The MNT was measured at 6 sites on the distal limb at 3 time points: before anesthesia (T0) and at 10 min (T10) and 30 min (T30) post-injection. Linear mixed-model analyses were done, with the significance level set at P < 0.05. Results: There was an increase in MNT (P = 0.001) across combined testing points between T0 and T30, indicating loss of skin sensation in the distal limb 30 min after TMTJ anesthesia. Regarding individual MNT sites, there were increases at the lateral proximal sesamoid bone (P = 0.002) and dorsal coronary band (P = 0.037) at T30 compared to T0. Conclusion: Intra-articular anesthesia of the TMTJ significantly increased the combined MNT of the skin of the distal limb at 30 min, indicating decreased skin sensation. Clinical relevance: Diagnostic anesthesia of the distal hind limb should be performed before TMTJ block. However, if patient compliance prevents this, lameness evaluation 10 min after blocking may enhance the reliability of interpretation.

Effets de l'anesthésie intra-articulaire de l'articulation tarsométatarsienne sur la sensation cutanée du membre distal chez le cheval. Objectif: Déterminer à l'aide d'un test de seuil nociceptif mécanique (MNT) si la sensation cutanée du membre distal est affectée par l'anesthésie intra-articulaire de l'articulation tarsométatarsienne (ATMT). Animaux et procédure: Il s'agissait d'une étude de cohorte prospective. Dix chevaux appartenant à des clients et ayant subi une anesthésie intra-articulaire pour l'ATMT ont été inclus dans l'étude. Le MNT a été mesuré sur 6 sites du membre distal à 3 moments: avant l'anesthésie (T0) et à 10 min (T10) et 30 min (T30) après l'injection. Des analyses linéaires sur modèles mixtes ont été effectuées, avec le niveau de signification fixé à P < 0,05. Résultats: Il y avait une augmentation du MNT (P = 0,001) sur tous les points de test combinés entre T0 et T30, indiquant une perte de sensation cutanée dans le membre distal 30 minutes après l'anesthésie du ATMT. En ce qui concerne les sites MNT individuels, il y avait des augmentations au niveau de l'os sésamoïde proximal latéral (P = 0,002) et de la bande coronaire dorsale (P = 0,037) à T30 par rapport à T0. Conclusion: L'anesthésie intra-articulaire du ATMT a augmenté de manière significative le MNT combiné de la peau du membre distal à 30 min, indiquant une diminution de la sensation cutanée. Pertinence clinique: Une anesthésie diagnostique du membre postérieur distal doit être réalisée avant le bloc de l'ATMT. Cependant, si l'observance du patient l'empêche, l'évaluation de la boiterie 10 minutes après le blocage peut améliorer la fiabilité de l'interprétation.(Traduit par Dr Serge Messier).

Ex Vivo Biomechanical Comparison of 4 Suture Materials for Laparoscopic Bladder Closure in the Horse.

OBJECTIVE: To compare a knotless, barbed suture to standard suture using laparoscopic suturing methods in an ex vivo model of equine bladder repair. STUDY DESIGN: Cadaveric study. SAMPLE POPULATION: Equine cadaver bladders (n=42). METHODS: A 5-cm incision was created and repaired in a laparoscopic training box with 4 different suture materials. Groups 1 and 2 used 2-0 poliglecaprone and 2-0 glycomer knotless, barbed suture, respectively, placed using laparoscopic instruments. Groups 3 and 4 used 0 and 2-0 polyglyconate knotless, barbed suture, respectively, placed using an automated laparoscopic suturing device. All groups used a double-layer inverting pattern. Time for suture placement was recorded. Bladders were inflated with water and bursting strength pressures recorded, including a control group of intact bladders. Statistical analysis using a linear model and taking into account the unequal variances was followed by a post-hoc Tukey's test. Significance was set at P<.05. RESULTS: Bursting strength did not vary significantly between treatment groups, but was significantly decreased compared to the control group (P<.001). Time to place the sutures with the 2 automated suture device groups (groups 3 and 4) was significantly faster than those in which the suture was placed using laparoscopic needle holders and forceps (groups 1 and 2; P=.001). CONCLUSION: Knotless, barbed suture may be a viable alternative to standard suture material for laparoscopic closure of the urinary bladder in horses. Further cyclic and in vivo testing should be performed before use in clinical cases.

Frequency of Undetected Glove Perforation and Associated Risk Factors in Equine Surgery.

OBJECTIVE: To estimate the frequency of undetected perforations in surgical gloves during equine surgery and to identify risk factors associated with occurrence. STUDY DESIGN: Observational cohort study. SAMPLE POPULATION: Surgical gloves-292 pairs. METHODS: Water leak tests were performed on gloves after equine surgery to detect perforations. Fifty pairs of unused gloves were also tested. Potential risk factors were recorded. Logistic regression was used to explore associations between putative risk factors and perforation. RESULTS: No perforations were detected in the unused gloves. Of 292 pairs of used gloves tested, 80 (27%) had at least one glove perforation per pair. The frequency of perforations was not different between surgery diplomates and residents (P=.69). The length and type of surgery were significantly associated with the likelihood of undetected glove perforation with surgeries longer than 60 minutes approximately 2.5 times more likely to result in glove perforation (P=.005). Surgery classified as soft tissue, orthopedic or exploratory celiotomy was 3 times more likely to result in glove perforation than minimally invasive surgery. The perforations occurred significantly more frequently in the nondominant hand (19%) than the dominant hand (11%) (P=.009). CONCLUSION: There is a high occurrence of undetected glove perforation in equine surgery. Precautions can be suggested based on this study although further investigation is required to assess whether glove perforations are associated with surgical site infections.

Comparison of 2 equine transfixation pin casts and the effects of pin removal.

OBJECTIVE: To (1) compare strain on the dorsal aspect of the proximal phalanx (P1) between 2 types of transfixation pin casts (TPC) and (2) evaluate the change in strain as the pins are removed. STUDY DESIGN: Experimental. ANIMALS: Equine cadaver forelimbs (n = 10 pair). METHODS: Each limb of a pair was assigned to 1 of 2 TPC constructs. Construct 1 consisted of a TPC with 2 positive profile, centrally threaded pins placed in the distal aspect of the third metacarpus (MC3) and construct 2 had 4 smooth Steinmann pins placed similarly. A strain gauge was mounted on P1 and axial compression (444.8-5337.9 N) applied. One forelimb of each pair was tested as a control with no construct in place. The 2 TPC groups were retested after removal of 1 proximal (n = 5 limbs) or distal (n = 5) pin from construct 1, and 2 proximal (n = 5) or distal (n = 5) pins from construct 2. Limb specimens were retested after all pins had been removed. RESULTS: There was a significant decrease in strain between both TPC constructs and the non-casted control at all loads except 444.8 N. There was no significant difference in strain reduction between the 2 TPC constructs. After proximal pin removal there was a 7% (construct 1) and 10% (construct 2) increase in strain. When distal pins were removed there was a 0.5% (construct 1) and 1% (construct 2) increase in strain. The difference between proximal and distal pin removal was only statistically different from each other at high loads. CONCLUSION: Both constructs provided equivalent reduction in strain. Removal of the proximal pin(s) increased the strain.

BEVA primary care clinical guidelines: Wound management in the horse.

BACKGROUND: There are currently no evidence summaries on wounds in the horse. OBJECTIVES: To develop evidence-based guidelines on wound management in the horse. STUDY DESIGN: Evidence review using the GRADE framework. METHODS: Research questions were proposed by a panel of veterinarians, and developed into PICO format. Evidence in the veterinary literature was evaluated using the GRADE evidence-to-decision framework. Searches for human evidence summaries were conducted in the NICE, Cochrane and JBI databases. Final recommendations were based on both veterinary and human evidence. RESULTS AND RECOMMENDATIONS: The research questions were categorised into three areas: A. Wound lavage and topical treatments; B. Wound debridement and closure; C. Therapeutics for wound healing. Three hundred and six veterinary publications were identified across thirteen different topics. Fourteen papers were assessed using the GRADE criteria. Twenty-five human evidence summaries were reviewed. The results were developed into recommendations: Wound lavage and topical treatments: (i) Tap water should be considered instead of saline for lavage; (ii) Povidone iodine lavage should be considered for contaminated wounds; (iii) Topical silver sulfadiazine may not be suitable for acute wounds; (iv) Optimal lavage pressures are around 13 psi. Wound debridement and closure: (i) Debridement pads should be considered for wound preparation; (ii) Larvae debridement should be considered in selected cases; (iii) Hydrosurgery should be considered in acute contaminated wounds. Therapeutics for wound healing: (i) Honey may reduce duration of some phases of wound healing. There was insufficient evidence to draw conclusions on the use of chemical debridement, therapeutic ultrasound, laser therapy, wound closure with staples compared to sutures, or identify optimal concentrations of antiseptic lavage solutions. MAIN LIMITATIONS: Low quality evidence in veterinary literature; majority of recommendations were based on human evidence. CONCLUSIONS: These findings should be used to inform decision-making in equine primary care practice.

In vitro comparison of a novel external fixator and traditional full-limb transfixation pin cast in horses.

OBJECTIVE: To compare the mechanical properties and failure modes of a standardized short oblique distal radial metaphyseal osteotomy stabilized using either a transfixation pin cast (TPC), a modular-sidebar external skeletal fixator (ESF), or a solid-sidebar ESF (modular- or solid-ESF, respectively) using static or cyclic axial loading to failure. STUDY DESIGN: In vitro study. ANIMALS: Equine cadaver forelimbs. METHODS: A 30 degrees oblique distal radial osteotomy was created and stabilized using 1 of the 3 fixation methods: (1) TPC, (2) modular-ESF, or (3) solid-ESF. Limbs were tested using static (TPC, modular-ESF, and solid-ESF) or cyclic (TPC and solid-ESF) axial loading to failure. The stiffness, yield load, yield displacement, failure load, and failure displacement for static loading and the cycles to failure for cyclic loading at 75% failure load were obtained. Data were analyzed using a Kruskal-Wallis test. Level of significance was P<.05. RESULTS: The solid-ESF had a greater stiffness, higher yield and failure load and a lower yield and failure displacement than the TPC (P=.01) and the modular-ESF (P=.02). TPC had a higher yield load, failure load, and yield displacement than the modular-ESF (P=.01). Mean cycles to failure for TPC was 2996+/-657 at a load of 16,000 N and for solid-ESF 6560+/-90 cycles at a load of 25,000 N. CONCLUSIONS: The solid-ESF was stiffer and stronger than the TPC and modular-ESF and failed at a greater number of cycles in axial loading compared with the TPC. CLINICAL RELEVANCE: This study is an initial step in evaluating the solid-ESF. Further testing needs to be performed, but this fixation may offer a viable alternative to the traditional TPC for stabilization of long bone fractures in adult horses.

Exophthalmus secondary to a sinonasal cyst in a horse.

CASE DESCRIPTION: A 13-year-old female Miniature Horse was evaluated for progressive unilateral exophthalmia of the left globe of 3 weeks' duration. CLINICAL FINDINGS: Results of a physical examination were unremarkable. Ophthalmic examination identified exophthalmus of the left globe with complete resistance to retropulsion and mild blepharoconjunctivitis. Computed tomography revealed a large, space-occupying mass within the left caudal maxillary and left conchofrontal sinuses. The mass extended into the left retrobulbar space and contacted the cribriform plate. Trephination yielded copious amounts of turbid yellow fluid. The diagnosis was a sinonasal cyst. TREATMENT AND OUTCOME: Subtotal surgical excision of the cyst via a frontonasal osteoplastic flap was curative, with complete resolution of the exophthalmus. Histologic examination confirmed diagnosis of a sinonasal cyst. There was no evidence of cyst recurrence by 4 months after surgery. CLINICAL RELEVANCE: Sinonasal cyst should be a differential diagnosis for retrobulbar disease in horses. Exophthalmia may be the only clinical finding in horses with a sinonasal cyst.

Analysis of sodium carboxymethylcellulose administration and related factors associated with postoperative colic and survival in horses with small intestinal disease.

OBJECTIVE: To analyze the effect of the intraoperative use of sodium carboxymethylcellulose (CBMC) and related perioperative factors on postoperative colic and survival in horses that had abdominal surgery for colic. STUDY DESIGN: Retrospective study. ANIMALS: Horses (n=203) that had surgery for small intestinal disease; 33 horses had intraoperative administration of CBMC. METHODS: Information was obtained from medical records for 170 horses that had surgery for colic before use of CBMC and 33 horses that had intraoperative CBMC. Kaplan-Meier survival curves were used to estimate median survival time and a Cox proportional hazards model was used to estimate the hazard ratio for the effect of CBMC and other perioperative variables on survival. RESULTS: Seventy-five percent of horses administered CBMC survived to 180 days, whereas 75% of untreated horses survived 8 days (median survival time=18 days). Horses not administered CBMC were twice as likely to die compared with horses administered CBMC. Horses that had postoperative ileus (POI) were 1.4 times more likely to die than horses without ileus. Similarly, horses with signs of colic after surgery were 1.3 times more likely to die than horses without postoperative signs of colic. CONCLUSIONS: CBMC administration is seemingly protective against death and prolongs survival when used intraoperatively in horses with small intestine disease, particularly horses with postoperative colic or POI. Both POI and colic increased risk of death after surgery. CLINICAL RELEVANCE: Intraoperative administration of CBMC in horses that have surgery for small intestinal disease may improve survival, possibly by reducing early adhesion formation.

Expression of cyclooxygenase-1 and -2 in naturally occurring squamous cell carcinomas in horses.

OBJECTIVE: To assess expression of cyclooxygenase (COX)-1 and -2 in naturally occurring squamous cell carcinomas (SCCs) and the analogous normal tissues in horses. SAMPLE POPULATION: Tissue samples collected from 3 conjunctival, 2 vulvar, 4 preputial, and 5 penile SCCs during surgical excision in 14 horses and from corresponding body regions (conjunctiva [n = 5 horses], vulva [2], prepuce [3], and penis [3]) in 5 horses euthanized for reasons unrelated to neoplasia. PROCEDURES: Tissue samples were snap frozen in liquid nitrogen and stored at -80 degrees C until analysis. Protein was extracted from the frozen tissues, and western blot analyses were performed. Nonneoplastic and abnormal tissues from each body region were run on the same blot, and blots were run in triplicate. Molecular-weight markers and COX-1 and 2 ovine standards (positive control samples) were run concurrently on the gels; negative control samples were not used. RESULTS: All tissues, including the nonneoplastic and SCC tissues, expressed both COX-1 and -2 proteins. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the expression of COX proteins in both nonneoplastic and SCC-affected tissues in horses is markedly different from that in other species. The reason for the potential benefit of COX-2 inhibitors in horses and other species is unknown. Further research needs to be performed to evaluate the efficacy of COX-2 inhibitors as cancer treatments in horses. Investigation of the mechanisms of tumor development in horses should be performed to increase understanding of this disease and ascertain how the mechanisms differ from those in other animals.

Infections in the equine abdomen and pelvis: perirectal abscesses, umbilical infections, and peritonitis.

This article addresses the pathophysiology, diagnosis, management, and prognosis of several different infections within the equine abdomen and pelvic region. The latest advances in the diagnosis and treatment of perirectal abscesses, umbilical infections, and local and diffuse peritonitis are discussed. Emphasis is placed on recent advances in diagnostics and therapeutics with reference to human literature that may be useful in equine practice.

Evaluation of survival rate and athletic ability after nonsurgical or surgical treatment of cleft palate in horses: 55 cases (1986-2008).

OBJECTIVE: To determine survival rate and athletic ability after nonsurgical or surgical treatment of cleft palate in horses. DESIGN: Retrospective case series. ANIMALS: 55 horses with cleft palate. PROCEDURES: 13 of the 55 horses died or were euthanized without treatment and were not included in all analyses. Medical records were reviewed for signalment, history, method of diagnosis, soft or hard palate involvement, type of surgical procedure performed, postoperative complications, and survival to hospital discharge. Information on athletic ability was acquired from race records and follow-up conversations with owners, trainers, or referring veterinarians. RESULTS: The predominant reason for initial evaluation was milk or feed in the nostrils (60%). The diagnosis was confirmed by means of videoendoscopy of the upper portion of the airway in all cases. Most cases involved the soft palate only (92.7%). Twenty-six of the 55 (47.3%) horses underwent surgical repair, and 12 of these had dehiscence at the caudal edge of the soft palate. Among potential racehorses, 14 of 33 had surgery. Of these, 12 of 14 survived to discharge and 2 horses raced. Among potential racehorses, 10 of 33 were discharged without surgery and 2 of these raced. Among nonracehorses, 12 of 22 underwent surgery and 11 survived to discharge. All horses that were discharged and for which follow-up information was available survived to 2 years of age or older without ill thrift despite dehiscence at the caudal edge of the soft palate and continued mild nasal discharge. CONCLUSIONS AND CLINICAL RELEVANCE: Horses with cleft palate had a higher survival rate than previously reported.

Bilateral ureterocystostomy to correct left ureteral atresia and right ureteral ectopia in an 8-month-old standardbred filly.

OBJECTIVES: To report the diagnosis and outcome after surgical correction of bilateral distal ureteral anomalies in a Standardbred filly. STUDY DESIGN: Clinical case report. ANIMAL: An 8-month-old, 310 kg Standardbred filly with left ureteral atresia and right ureteral ectopia. METHODS: The filly was admitted for evaluation of incontinence since birth and severe urine scalding of the hindquarters. Diagnosis was made by both direct (cystoscopy and vaginoscopy) and indirect (intravenous pyelography, ultrasonography, and scintigraphy) evaluation of the ureters and bladder. The filly had left ureteral atresia, hydronephrosis, and decreased left-sided renal function and right ureteral ectopia before surgery. Surgical correction was performed on the left by an end-to-side stapled anastomosis technique and on the right by a side-to-side hand-sewn anastomosis technique. RESULTS: Surgical correction was successful. The filly had no postoperative complications and remained continent 18 months after surgery. Left renal function improved. CONCLUSION: Ureteral anomalies can be successfully repaired in larger (>300 kg) foals and some renal function may be restored after surgical correction. CLINICAL RELEVANCE: Scintigraphy should be considered in diagnosis of ureteral anomalies, assessing renal function, and determining prognosis for horses with hydronephrosis caused by ureteral ectopia and atresia.

Arthroscopic removal of dorsoproximal chip fractures of the proximal phalanx in standing horses.

OBJECTIVE: To report a technique for, and outcome after, arthroscopic removal of dorsoproximal chip fractures of a proximal phalanx in standing horses. STUDY DESIGN: Retrospective study. ANIMALS OR SAMPLE POPULATION: A total of 104 horses, 1 to 13 years of age, with a dorsoproximal chip fracture of a proximal phalanx. METHODS: Horses were restrained in standing stocks and sedated with intravenous xylazine, detomidine, or a combination of both drugs. Local analgesia was achieved with 2% mepivacaine administered intra-articularly and by subcutaneous infiltration in a crescent-shaped block dorsal to the fetlock. Sterile drapes were placed on the surgical field, and impervious drapes were used on the hoof and floor. Arthroscopic portals were created in the dorsal pouch of the metacarpophalangeal or metatarsophalangeal joints to remove chip fractures. Statistical analysis was performed on race records for all Thoroughbred racehorses and compared with previously published studies. Operative and hospitalization times were compared with those of the general hospital population, and risks associated with general anesthesia were examined. RESULTS: No major operative or postoperative complications occurred. Ninety-one percent of racehorses raced after surgery with 78% returning to race at the same or higher level. CONCLUSION: Standing arthroscopic surgery can be performed successfully to remove dorsoproximal chip fractures of the proximal phalanx. CLINICAL RELEVANCE: Standing arthroscopic surgery is a valid alternative treatment for experienced surgeons to avoid the expense and potential risks associated with general anesthesia.

Unilateral thyroidectomy in 6 horses.

OBJECTIVE: To describe the surgical technique, complications, and outcome of thyroidectomy in 6 horses. STUDY DESIGN: Retrospective study. ANIMALS: Six horses, 10 to 22 years of age, with unilateral, rapidly enlarging thyroid masses. METHODS: Medical records between 1985 and 2000 were reviewed for horses that had unilateral thyroidectomy. Retrieved data included signalment, physical, clinical, and ultrasonographic examination findings, surgical technique, complications, and outcome. A minimum of 6 months follow-up was obtained. RESULTS: Six horses were identified. Three horses had tracheal compression and 2 of these also had exercise intolerance. On ultrasonography (5 horses), the enlarged thyroid ranged from 125 to 990 cm(3), and had either a heterogeneous (1 horse), cystic (2), or homogeneous (2) appearance. En bloc, unilateral thyroidectomy under general anesthesia was performed in all horses. After surgery, 3 horses had ipsilateral laryngeal hemiplegia, but tracheal compression was resolved. Thyroid masses were adenoma (3), C-cell compact carcinoma (1), and adenocarcinoma (1). No tumor recurrence or metastatic disease was reported 6 to 14 months after surgery. CONCLUSIONS: Unilateral thyroidectomy can be successfully performed in horses with large thyroid tumors, but laryngeal hemiplegia can be an important surgical complication. Ultrasonographic examination is useful to define thyroid enlargement and location but is seemingly not useful to characterize tumor type. CLINICAL RELEVANCE: Thyroidectomy is an uncommon surgical procedure and has an attendant risk for recurrent laryngeal nerve damage. Laryngoscopic examination before and after surgery and careful isolation of the recurrent laryngeal nerve during surgery is recommended.