Laparoscopic cryptorchidectomy using a resorbable self-locking loop device in dorsally recumbent horses.

OBJECTIVE: To report the use and feasibility of a self-locking resorbable loop device for cryptorchidectomy. STUDY DESIGN: Clinical prospective study. POPULATION: Twenty horses. METHODS: Horses suspected to have an abdominal testicle/s after admission work-up were enrolled. Horses were anesthetized in dorsal recumbency and a standard laparoscopic technique was performed. The looped device was inserted into the abdomen, glided around the testis/cord and tightened. Then, the spermatic cord was transected prior testis removal. Surgical procedure details and remarks, perioperative complications and total surgical time were recorded. Short- (>3 weeks) and long-term (>6 months) follow-ups were obtained by telephone questionnaire. RESULTS: Median total surgical time was 67 min (range: 43-189 min) and significantly shortened after the first four horses. The loop device was easily glided around 13/20 abdominal testes and required more time and technical skills around larger testes (≥3 years). Excellent intraoperative hemostasis was achieved in 17 horses. Three horses demonstrated mild intraoperative bleeding that required retightening, device replacement or adding a second device, respectively. Three horses developed mild postoperative hemoabdomen identified ultrasonographically and were successfully managed medically. Follow-up revealed no significant complications related to the procedure. One horse was euthanized for colic 4 months after surgery and one died of hemolytic shock 17 months postoperatively. CONCLUSION: This device represents another method to perform equine cryptorchidectomy that requires minimal training and laparoscopic expertise but demands knowledge of the device and application to prevent complications. CLINICAL SIGNIFICANCE: Laparoscopic cryptorchidectomy using this device is an alternative technique for horses <3 years.

Minimally invasive ultrasound-assisted cutting thread tenotomy of the deep digital flexor tendon in horses: An ex vivo study.

OBJECTIVE: To evaluate the feasibility and limitations associated with a minimally invasive ultrasound-assisted cutting thread technique for tenotomy of the deep digital flexor tendon (DDFT) in horses. STUDY DESIGN: Ex vivo study. SAMPLE POPULATION: Twenty cadaveric forelimbs. METHODS: Forelimbs were placed on a jig to mimic a standing semiflexed position and the midmetacarpal region was prepared to perform tenotomy of the DDFT using a percutaneous technique with a cutting thread. For that purpose, the thread was placed percutaneously around the DDFT (first dorsally and then palmarly) with the aid of a curved 20 gauge spinal needle. Tendon palpation/manipulation and ultrasonographic assessment assisted thread placement. Procedure time and skin puncture size were recorded. Limbs were then dissected to evaluate the degree of DDFT transection and the presence of any iatrogenic lesions. RESULTS: The DDFT was completely transected in all cases. Minor lesions of the superficial digital flexor tendon were found in 11/20 limbs and considered clinically irrelevant. However, the neurovascular bundle was damaged in 6/20 limbs (four limbs had nerve damage and two limbs had a nerve and either a palmar artery or vein damaged). The skin puncture hole sizes ranged from undetectable to 5 mm long. The average duration of the procedure was 7 min and 38 s (range: 4 min 56 s to 10 min 19 s). CONCLUSION: A DDFT tenotomy can be performed reliably with a percutaneous cutting thread technique. However, refinement of the technique is required to minimize iatrogenic damage. CLINICAL SIGNIFICANCE: The reported technique allows a DDFT tenotomy to be performed in a minimally invasive manner and has the potential to be clinically applicable.

Standing Surgical Management of Splint Bone Fractures in 13 Horses: A Comparison to Management Under General Anaesthesia.

OBJECTIVE: The aim of this article was to describe the technique and outcomes of standing surgical management of splint bone fractures and to compare outcome variables and hospitalization cost to a group with similar fractures treated under general anaesthesia. STUDY DESIGN: It is a single-institution retrospective study. Surgical technique, surgical time, hospitalization cost and complications were retrieved from the medical records of horses treated surgically for splint bone fractures (2008-2020). Owner telephone follow-up provided data about athletic outcome, client satisfaction and cosmetic appearance. RESULTS: Forty-nine horses (13 standing, 36 under general anaesthesia) with 57 fractures (18 contaminated and 39 non-contaminated) were included. Seven fractures were in the proximal third (4 standing, 3 under general anaesthesia), 18 in the middle third (5 standing, 13 under general anaesthesia) and 30 were distal (4 standing, 26 under general anaesthesia). No significant difference between groups in surgical time was found (p= 0.8). Average total cost was 522 CAN$ lower for the standing group for non-contaminated fractures (p= 0.02). Three horses of the general anaesthesia group demonstrated postoperative colic signs and one case of the standing group was re-operated due to sequestration. Based on follow-up information (range: 3.8-151.2 months), no significant differences in cosmetic and athletic outcomes were found between groups. CONCLUSION: Surgical management of splint bone fractures in the standing horse is a valuable alternative for horses selected based on behaviour. When compared to general anaesthesia, standing management of splint bone fractures did not alter the surgical time or outcome variables and avoided general anaesthesia-associated risks.

Minimally invasive removal of obstructive ureteral stones by intracorporeal lithotripsy in horses: 3 patients.

Three client-owned horses diagnosed with obstructive ureteral stones were referred and treated in a minimally invasive manner by retrograde ureteroscopy in conjunction with electrohydraulic lithotripsy (EHL) or laser Holmium:YAG lithotripsy (HYL). For all 3 horses, additional tests revealed variable degrees of azotemia and ureteral obstruction. Ultrasound examination (2 horses) revealed a loss of cortico-medullary distinction consistent with a chronic nephropathy. Ultrasound-guided biopsy of the right kidney in 1 horse revealed moderate glomerulosclerosis and lymphoplasmacytic nephritis. A standing anesthesia with a coccygeal epidural was done for each horse. A perineal urethrotomy was performed in 2 horses before the urethrocystoscopy. One horse was treated with Holmium:YAG laser lithotripsy and 2 others were treated using a electrohydraulic lithotripsy probe. Each procedure was successful. The ureteroscopy was successfully performed and visualization was excellent. Fragmentation of stones seemed easier with the electrohydraulic lithotripsy probe. No complications, pain, or signs of discomfort after the procedure were noticed. All 3 horses were discharged from the hospital. Key clinical message: Obstructive ureteral stones in horses can be successfully treated in a minimally invasive manner by retrograde ureteroscopy accompanied by lithotripsy. This technique is safe, not painful and did not require general anesthesia. Electrohydraulic lithotripsy appeared superior for stone fragmentation.

Exérèse minimalement invasive de calculs urétéraux obstructifs par lithotritie intracorporelle chez le cheval : trois patients. Trois chevaux appartenant à des clients diagnostiqués avec des calculs urétéraux obstructifs ont été référés et traités de manière peu invasive par urétéroscopie rétrograde en conjonction avec une lithotripsie électrohydraulique (EHL) ou une lithotripsie au laser Holmium:YAG (HYL). Pour les trois chevaux, des tests supplémentaires ont révélé des degrés variables d'azotémie et d'obstruction urétérale. L'échographie (deux chevaux) a révélé une perte de distinction cortico-médullaire compatible avec une néphropathie chronique. La biopsie échoguidée du rein droit chez un cheval a révélé une glomérulosclérose modérée et une néphrite lymphoplasmocytaire. Une anesthésie debout avec une péridurale coccygienne était effectuée pour chaque cheval. Une urétrotomie périnéale a été réalisée chez deux chevaux avant l'urétrocystoscopie. Un cheval a été traité par lithotripsie au laser Holmium:YAG et deux autres ont été traités à l'aide d'une sonde de lithotripsie électrohydraulique. Chaque procédure a réussi. L'urétéroscopie a été réalisée avec succès et la visualisation était excellente. La fragmentation des calculs semblait plus facile avec la sonde de lithotripsie électrohydraulique. Aucune complication, douleur ou signe d'inconfort après la procédure n'a été remarqué. Les trois chevaux ont obtenu leur congé de l'hôpital.Message clinique clé :Les calculs urétéraux obstructifs chez les chevaux peuvent être traités avec succès de manière peu invasive par urétéroscopie rétrograde accompagnée de lithotripsie. Cette technique est sûre, non douloureuse et ne nécessite pas d'anesthésie générale. La lithotritie électrohydraulique est apparue supérieure pour la fragmentation des calculs.(Traduit par Dr Serge Messier).

Standing surgery among equine board certified surgeons: Survey regarding current use and trends.

BACKGROUND: Publications about equine standing surgery are flourishing, however, information regarding its use and prevalence among surgeons is still limited. OBJECTIVES: To determine the current use and recent trends for equine standing surgery among board certified surgeons and to identify the main reasons and limitations for performing a procedure standing. STUDY DESIGN: Cross-sectional survey. METHODS: A 139-item questionnaire was sent by email to 733 large animal surgery Diplomates (ACVS and ECVS) from November 2020 to February 2021. The survey collected demographic information and general data regarding standing surgery before being divided into seven identical sections for each body system, involving 36 standing procedures. RESULTS: The survey response rate was 29.7% (218/733). Most respondents (58.9%, 126/214) had performed standing surgery for <10 years regardless of length of time they were board certified (48.2% board certified <10 years and 51.8% >10 years). Most respondents (range: 50.0%-92.9%, mean 69.5%) changed from performing 14/36 surgeries under general anaesthesia (GA) to standing within the previous 10 years and had always performed 8/36 surgeries standing (51.6%-73.9%, mean 61.4%) regardless of board certification time. Surgeons board certified <10 years ago performed more often 3/36 listed procedures standing than those board certified >10 years ago (p < 0.05). Avoiding GA (179/218) and/or reducing procedure cost (111/218) were the two main reasons to perform standing surgeries whereas the horse's behaviour (183/218) and/or the patient size/age (94/218) were the two main limiting factors. MAIN LIMITATIONS: Low response rate. Results biased towards the opinion of a subgroup of surgeons, those performing standing surgery. Some standing procedures were not included in the survey. CONCLUSIONS: The use of standing surgery is well established among board certified surgeons and progressively increasing, especially in the last 10 years and among recent Diplomates. With increased training and awareness, more Diplomates may be encouraged towards performing standing surgeries.

Effects of azithromycin on bronchial remodeling in the natural model of severe neutrophilic asthma in horses.

Steroid resistance in asthma has been associated with neutrophilic inflammation and severe manifestations of the disease. Macrolide add-on therapy can improve the quality of life and the exacerbation rate in refractory cases, possibly with greater effectiveness in neutrophilic phenotypes. The mechanisms leading to these beneficial effects are incompletely understood and whether macrolides potentiate the modulation of bronchial remodeling induced by inhaled corticosteroids (ICS) is unknown. The objective of this study was to determine if adding azithromycin to ICS leads to further improvement of lung function, airway inflammation and bronchial remodeling in severe asthma. The combination of azithromycin (10 mg/kg q48h PO) and inhaled fluticasone (2500 µg q12h) was compared to the sole administration of fluticasone for five months in a randomized blind trial where the lung function, airway inflammation and bronchial remodeling (histomorphometry of central and peripheral airways and endobronchial ultrasound) of horses with severe neutrophilic asthma were assessed. Although the proportional reduction of airway neutrophilia was significantly larger in the group receiving azithromycin, the lung function and the peripheral and central airway smooth muscle mass decreased similarly in both groups. Despite a better control of airway neutrophilia, azithromycin did not potentiate the other clinical effects of fluticasone.

Pharmacokinetics of ceftiofur in the metacarpophalangeal joint after standing intravenous regional limb perfusion in horses.

This study investigated the pharmacokinetics of ceftiofur after intravenous regional limb perfusion (IVRLP). Six horses were involved in 3 IVRLP sessions. For each session, operators with varying clinical experience placed the tourniquet. A wide-rubber tourniquet was applied in the antebrachium as 2 g of ceftiofur in a total volume of 100 mL was injected into the cephalic vein. Plasma and metacarpophalangeal synovial fluid samples were obtained to evaluate perfusate leakage and synovial fluid concentrations of ceftiofur over 24 h. Overall, mean plasma concentrations were not significantly different before and after tourniquet removal. Mean synovial fluid ceftiofur concentrations were significantly higher 5 min and 8 h after tourniquet removal versus 24 h, after which values above the minimum inhibitory concentration (MIC) (1 µg/mL) were not detected. Concentrations above the MIC were detected in 72% and 50% of the horses at 5 min and 8 h, respectively. Overall, higher synovial fluid concentrations were obtained for the operator with the most recent clinical experience performing IVRLP.

Pharmacocinétique du ceftiofur dans l'articulation métacarpophalangienne après perfusion intraveineuse loco-régionale chez le cheval debout. Cette étude a examiné la pharmacocinétique du ceftiofur après perfusion intraveineuse loco-régionale des membres (PLR). Six chevaux ont participé à trois séances PLR. Pour chaque séance, un opérateur d'expérience clinique différente a placé le garrot. Un garrot large en caoutchouc a été appliqué dans l'avant-bras tandis que 2 g de ceftiofur dans un volume total de 100 mL ont été injectés dans la veine céphalique. Des échantillons de plasma et de liquide synovial métacarpophalangien ont été prélevés pour évaluer les fuites de perfusion et les concentrations de liquide synovial de ceftiofur au fil du temps. Dans l'ensemble, les concentrations plasmatiques moyennes n'étaient pas significativement différentes avant et après le retrait du garrot. Les concentrations moyennes de ceftiofur dans le liquide synovial étaient significativement plus élevées 5 min et 8 h après le retrait du garrot par rapport à 24 h, où les valeurs supérieures à la CMI (1 µg/mL) n'étaient pas détectées. Des concentrations supérieures à la CMI ont été détectées chez 72 % et 50 % des chevaux à 5 min et 8 h, respectivement. Des concentrations plus élevées de liquide synovial ont été obtenues pour l'opérateur avec une expérience clinique plus récente sur PLR.(Traduit par les auteurs).

Use of Clinical Audits to Evaluate Timing of Preoperative Antimicrobials in Equine Surgery at a Veterinary Teaching Hospital.

Based on human surgical guidelines, intravenous antimicrobials are recommended to be administered within 60 min of surgical incision. Achieving this target in horses is reportedly challenging and influenced by hospital policies. The objectives of this study were to evaluate and improve: (1) the timing of antimicrobial administration to surgical incision (tAB-INC), (2) contributions of anesthesia pre-induction (tPRI) and surgical preparation (tPREP) periods to tAB-INC, and the (3) completeness of antimicrobial recording. Two clinical audits were conducted before and after the policy changes (patient preparation and anesthesia record keeping). tPRI, tPREP, and tAB-INC were calculated and compared for elective arthroscopies and emergency laparotomies within and between the audits. The percentage of procedures with a tAB-INC <60 min was calculated. Antimicrobial recording was classified as complete or incomplete. A median tAB-INC <60 min was achieved in laparotomies (audit 1; 45 min, audit 2; 53 min) with a shorter tPREP than arthroscopies (p < 0.0001, both audits). The percentage of procedures with tAB-INC <60 min, tAB-INC, tPRI, and tPREP durations did not improve between the audits. There was a positive correlation between the number of operated joints and tPREP (audit 1, p <0.001, r = 0.77; audit 2, p < 0.001, r = 0.59). Between audits, antimicrobial recording significantly improved for elective arthroscopies (82-97%, p = 0.008) but not emergency laparotomies (76-88%, p = 0.2). Clinical audits successfully quantified the impact of introduced changes and their adherence to antimicrobial prophylaxis guidelines. Antimicrobial recording was improved but further policy changes are required to achieve a tAB-INC <60 min for arthroscopies.

Desensitisation of the distal forelimb following intrathecal anaesthesia of the carpal sheath in horses.

BACKGROUND: The effect of intrathecal anaesthesia of the carpal sheath on distal forelimb sensitivity in horses remains unknown. OBJECTIVES: To assess the effect of carpal sheath anaesthesia on skin sensitivity of the distal forelimb and to determine potential locations for desensitisation of palmar nerves. STUDY DESIGN: In vivo experimental and descriptive anatomical studies. METHODS: Mepivacaine hydrochloride 2% (0.6 mg/kg) was injected unilaterally in the carpal sheath of 8 horses. Mechanical nociception of the distal forelimb was measured with a dynamometer and compared with the control limb at t0, t15, t30, t60, t90, t120 and t180 minutes . Additionally, the carpal sheath of 10 pairs of cadaveric limbs was injected with latex and potential locations for anaesthetic diffusion to the neighbouring nerves were identified during longitudinal dissection (one limb) and in 3-cm-thick transverse cuts (opposite limb). RESULTS: Six of 8 horses (75%) were completely desensitised at the level of both heel bulbs. Anaesthetic injection was not smooth in the 2 horses without desensitisation. Desensitisation started between 30 and 60 minutes in 67% of desensitised heel bulbs (8/12), and 50% (6/12) of them were still completely desensitised at 180 minutes. Cadaveric specimens revealed close proximity between the sheath and the medial palmar nerve as it travels inside the mesotenon of the digital flexor tendons in the carpal region and with both palmar nerves at the proximal metacarpal region. MAIN LIMITATIONS: Skin mechanical nociception does not necessarily correlate with deep pain but remains the main clinical tool used by practitioners to assess distal limb anaesthesia. CONCLUSIONS: Intrathecal anaesthesia of the carpal sheath led to distal limb skin desensitisation through diffusion to the palmar nerves at 2 possible locations. Carpal sheath anaesthesia should be interpreted within 15 minutes following injection and anaesthetic blocks distal to the carpus should be delayed for more than 3 hours following carpal sheath anaesthesia.

Diagnostic needle arthroscopy of the scapulohumeral joint in standing sedated horses.

OBJECTIVE: To describe the technique to perform diagnostic standing scapulohumeral joint needle arthroscopy with a 1.2-mm-diameter arthroscope in horses. STUDY DESIGN: Experimental study. ANIMALS: Eight thoracic limbs in phase 1 and six horses in phase 2. METHODS: In phase 1, the feasibility of the technique was evaluated by using a craniolateral arthroscopic approach. An evaluation of the visible structures of the scapulohumeral joint was performed with both a needle arthroscope and a 4-mm-diameter arthroscope. In phase 2, the technique was performed in six healthy sedated horses to validate the technique in live animals and to report any complications or limitations. RESULTS: In phase 1, joint evaluation was similar between arthroscopes and allowed complete evaluation of approximately the lateral half of the humeral head and the lateral glenoid rim. In phase 2, all joints were successfully accessed, and fluid extravasation was mild. Arthroscopic visualization was complete for the centrolateral aspect of the joint in all horses and either complete (3/6) or partial (3/6) for the craniolateral and caudolateral structures, respectively. The procedure was rapidly performed and well tolerated, and no postoperative complications occurred. CONCLUSION: The described technique was simple and allowed direct inspection of the scapulohumeral joint. Nonetheless, the standing nature of the technique prevents evaluation of the medial aspect of the humeral head and most of the glenoid cavity. CLINICAL SIGNIFICANCE: Needle arthroscopy of the scapulohumeral joint is feasible in horses and offers a diagnostic technique that may improve the surgeon's diagnostic ability for certain shoulder pathologies.

Influence of abdominal elevation on radiographic measurements of the thoracolumbar interspinous spaces in asymptomatic horses.

The objective of this study was to determine if abdominal elevation could induce radiographically visible widening of the interspinous spaces in the thoracolumbar region of standing sedated horses and facilitate the surgical approach to the region. Radiographs centered on T13 and T18 were taken while applying different degrees of tension on a wide strap placed under the abdomen of 7 healthy horses. Then, the interspinous spaces between T11 and L2 were measured following a standardized method. The interspinous spaces widen radiographically between T11 to L2, except for T18-L1. Thus, the reported technique could potentially facilitate the surgical approach for horses with impinging and overriding dorsal spinous processes.

Influence de l'élévation abdominale sur les mesures radiographiques des espaces intervertébraux thoraco-lombaires chez des chevaux asymptomatiques. L'objectif de la présente étude était de déterminer si l'élévation abdominale pouvait causer un élargissement radiographique visible des espaces intervertébraux dans la région thoraco-lombaire de chevaux sous sédation en position debout et faciliter l'approche chirurgicale de la région. Des radiographies centrées sur T13 et T18 furent prises tout en appliquant différents degrés de tension sur une large courroie placée sous l'abdomen de sept chevaux en santé. Puis, les espaces intervertébraux entre T11 et L2 furent mesurés en suivant une méthode standardisée. Les espaces intervertébraux s'élargissaient radiographiquement entre T11 à L2, sauf pour T18­L1. Ainsi, la technique radiographique rapportée ici pourrait potentiellement faciliter l'approche chirurgicale chez des chevaux avec empiètement et chevauchement des apophyses épineuses.(Traduit par Dr Serge Messier).

Needle arthroscopy of the radiocarpal and middle carpal joints in standing sedated horses.

OBJECTIVE: To develop a technique for standing diagnostic needle arthroscopy of the radiocarpal and middle carpal joints in standing sedated horses. STUDY DESIGN: Experimental study. ANIMALS: Six cadaveric forelimbs (phase 1) and six healthy horses (phase 2). METHODS: In phase 1, six cadaveric forelimbs were used to assess needle arthroscopic evaluation of both joints. Six healthy horses were subsequently enrolled in phase 2 to validate the procedure in live animals. The joint was maintained in flexion with a custom-made splint and base. RESULTS: In phase 1, needle arthroscopy allowed thorough evaluation of the dorsal and palmar recesses of both joints with traditional arthroscopic portals. In phase 2, joint evaluation was also thorough but only dorsal approaches were performed. All horses underwent radiocarpal joint arthroscopy, whereas the middle carpal joint was evaluated in only three of six horses because of limb movement. The technique was quickly performed and well tolerated by all horses. Complications included moderate movement, mild iatrogenic cartilage damage, and mild hemarthrosis. CONCLUSION: Standing needle arthroscopy allowed thorough evaluation of the dorsal aspect of both joints, although only three of six middle carpal joints were assessed because of movement limitations. CLINICAL SIGNIFICANCE: The proposed technique offers an alternative diagnostic tool for radiographically silent intra-articular lesions of the carpus while initially avoiding the cost and risks associated with general anesthesia. Arthroscopy of a single joint is recommended to minimize risks associated with movement during the procedure.

Antimicrobial susceptibility patterns of bacterial isolates cultured from synovial fluid samples from horses with suspected septic synovitis: 108 cases (2008-2017).

OBJECTIVE: To describe the antimicrobial susceptibility patterns of the most commonly isolated bacteria cultured from synovial fluid samples from horses with suspected septic synovitis treated at an equine referral hospital between May 1, 2008, and September 24, 2017. SAMPLE: 131 synovial fluid samples from 108 client-owned horses. PROCEDURES: A retrospective medical record search was conducted to identify horses with suspected septic synovitis and results of synovial fluid bacterial culture and antimicrobial susceptibility testing. Data collected included signalment, known or suspected origin of synovial contamination, synovial structures affected, antimicrobial treatment, and results of synovial fluid cytologic evaluation and bacterial culture and susceptibility testing. Horses were grouped as adults (≥ 6 months old) or foals (< 6 months old). RESULTS: Results of bacterial culture were positive for 34 of 70 (49%) and 18 of 61 (30%) samples from 68 adult horses and 40 foals, respectively. Gram-positive bacteria were more common in adult horses, whereas gram-negative bacteria were more common in foals. No multidrug-resistant microorganisms were identified. For adult horses, 92% (23/25) of gram-positive isolates tested with penicillin and gentamicin were susceptible to the combination. For foals, 94% (15/16) of isolates tested with penicillin, gentamicin, or both had susceptibility to 1 or both antimicrobials. CONCLUSIONS AND CLINICAL RELEVANCE: Periodic review of bacterial profiles and antimicrobial susceptibility in horses with septic synovitis can help to detect early changes in bacterial pressure and antimicrobial resistance. Findings suggested that in the geographic area we serve, a combination of penicillin and gentamicin would be an effective empirical antimicrobial treatment for most horses with septic synovitis while results of bacterial culture and susceptibility are pending.

Diagnostic needle arthroscopy of the tarsocrural joint in standing sedated horses.

OBJECTIVE: To develop and assess a needle arthroscopic technique to diagnose conditions of the tarsocrural joint (TCj) in standing sedated horses. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Six cadaveric hind limbs (phase 1) and six healthy horses (Phase 2). METHODS: In phase 1, each TCj was examined with a 1.2-mm-needle arthroscope. Suitability of the needle arthroscope and degree of joint visualization with traditional arthroscopic approaches were assessed. In phase 2, the feasibility of the procedure was assessed in six standing healthy horses. A custom-made splint and base were developed to maintain joint flexion during the procedure. RESULTS: Thorough evaluation of the dorsal intra-articular structures of the TCj via dorsomedial and dorsolateral approaches was possible in both phases. The procedure was feasible, quickly performed, and well tolerated by all horses. Complications consisted of moderate movement (2/6 horses) and hemarthrosis (3/6 horses). CONCLUSION: Diagnostic standing needle arthroscopy of the TCj allowed thorough evaluation of the dorsal aspect of the joint while avoiding the cost and risks associated with general anesthesia. Inadvertent puncture of the dorsomedial vasculature with the cannula and obturator led to significant hemarthrosis. CLINICAL IMPACT: Needle arthroscopy of the TCj offers an alternative diagnostic tool when traditional imaging techniques (radiography and ultrasonography) are unrewarding or nondiagnostic. The technique is conceived mainly for diagnostic purposes, but its use during short interventions warrants investigation.

Diagnostic tenoscopy of the carpal sheath with a needle arthroscope in standing sedated horses.

OBJECTIVE: To investigate the use of a needle arthroscope for diagnostic tenoscopy of the carpal sheath in standing horses. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Six forelimbs for the cadaveric part of the study and six horses for the in vivo part of the study. METHODS: Six cadaveric limbs were used to perform carpal sheath tenoscopy with a 1.2-mm-diameter needle arthroscope (65 and 100 mm long), followed by tenoscopy with a 4-mm arthroscope through a standard proximolateral approach. Then, unilateral standing carpal sheath tenoscopy was performed in six healthy sedated horses with a 65-mm-long needle arthroscope. Limbs were maintained in flexion during the procedure by using a custom-made splint and base. Degree of tenoscopic evaluation, safety, horse tolerance, and complications were recorded. RESULTS: Visibility at the most distal aspect of the sheath was absent for the needle arthroscopes vs a standard arthroscope. The maneuverability with a 65-mm needle arthroscope was excellent and allowed exhaustive visualization of the proximal region of the carpal sheath in cadaveric limbs and standing horses (six of six). However, visualization of the intertendinous recess was partial in most horses (four of six) vs cadavers (complete in six of six) because of remaining flexor tendon tension in standing horses. No major complications were encountered. CONCLUSION: Standing carpal sheath tenoscopy allowed a safe and thorough evaluation of most structures in the proximal region of the sheath and offers an alternative diagnostic technique. CLINICAL SIGNIFICANCE: Horses with unrewarding results after traditional imaging or that require an accurate diagnosis before treatment may benefit from this alternative procedure.

Standing Needle Arthroscopy of the Metacarpophalangeal and Metatarsophalangeal Joint for Removal of Dorsal Osteochondral Fragmentation in 21 Horses.

OBJECTIVE: The aim of this study was to report the technique, experience and outcome of standing arthroscopic removal of dorsal osteochondral fragmentation of the metacarpophalangeal and metatarsophalangeal joint using a 1.2-mm needle arthroscope. STUDY DESIGN: This was a prospective clinical study. MATERIALS AND METHODS: All horses referred for standing arthroscopic removal of dorsoproximal first phalanx fragments or fragments embedded in the distal aspect of the synovial plica were included. Relevant information from the cases was recorded. Follow-up was obtained by a telephone questionnaire. RESULTS: Twenty-one horses with a mean age of 4.5 years old were included. Osteochondral fragments removed were from the proximal margin of first phalanx in 18 horses (24 joints), in the synovial plica in 2 horses (2 joints) or free-floating fragment in 1 horse (1 joint). Fifteen out of twenty-one horses were unilaterally affected and 6/21 bilaterally. Fifteen out of twenty-seven affected joints were forelimbs and 12/27 hindlimbs. All articular structures within the dorsal recess of the joint were visible. The arthroscope was deemed easy to use and manoeuvre. Only minor complications occurred during the procedure. Surgery time was 15 to 20 minutes for most patients. CONCLUSIONS: All fragments were successfully removed and needle arthroscopy allowed a thorough evaluation of the dorsal aspect of the joint. The technique offers an alternative for standing fetlock arthroscopy for surgeons concerned about equipment damage or portability.

Concurrent or sequential tibial subchondral cystic lesions in 4 horses with medial femoral condyle subchondral cystic lesions.

CASE DESCRIPTION 4 horses were examined because of signs of chronic hind limb lameness. CLINICAL FINDINGS 3 horses had a history of lameness for > 6 months; specific duration was unknown for 1 horse. On initial evaluation, grade 3 to 4 (on a scale from 1 to 5) hind limb lameness was present in all 4 horses. Radiography of the stifle joint of the affected limb revealed medial femoral condyle subchondral lucencies or subchondral cystic lesions (SCLs) in all 4 horses, medial femorotibial osteoarthritis in 3 horses, and medial tibial condyle SCLs in 3 horses. TREATMENT AND OUTCOME 2 horses were treated medically (stall rest and oral NSAID administration), and 2 horses were treated surgically by means of medial femoral transcondylar lag screw placement through the medial femoral condyle SCLs. The 2 horses treated medically did not improve and were euthanized. Necropsy confirmed the presence of medial femoral condyle and medial tibial condyle SCLs. Surgical treatment did not resolve the lameness in 1 horse with SCLs in the medial tibial condyle and medial femoral condyle, and euthanasia was performed 150 days after surgery. In the second horse, a medial tibial condyle SCL was evident on radiographs obtained 3 months after surgery; however, this was not addressed surgically, and signs of lameness resolved 11 months after surgery. CLINICAL RELEVANCE Results of this small case series suggested that SCLs in the medial tibial condyle can occur in association with SCLs of the medial femoral condyle, with a poor prognosis for return to athletic function in affected horses. Further investigation is indicated.

Potential for iatrogenic coil embolization of the caudal cerebellar artery during treatment of internal carotid artery bifurcation in two horses with guttural pouch mycosis.

CASE DESCRIPTION: 2 horses were examined for chronic nasal discharge secondary to unilateral guttural pouch mycosis. CLINICAL FINDINGS: Initial endoscopic examination of both horses confirmed the presence of a fungal plaque on the dorsomedial aspect of the medial compartment of the guttural pouch (auditory tube diverticulum) involving the internal carotid artery (ICA). No signs of hemorrhage or neurologic deficits were present at admission. TREATMENT AND OUTCOME: Transarterial stainless steel coil embolization of the affected ICA was performed under general anesthesia, with fluoroscopic guidance. During treatment, an aberrant branch of the ICA, or a proposed bifid ICA, that anastomosed with the caudal cerebellar artery was identified. Occlusion of the distal (noncardiac) side of the aberrant branch was performed in both horses because of potential mycotic involvement at that level. Following treatment, resolution of the mycotic infection was observed in both horses; however, 1 horse developed neurologic signs compatible with unilateral caudal cerebellar artery ischemia on recovery from anesthesia; these signs resolved over the following 2 months. CLINICAL RELEVANCE: Findings highlighted variability of the anatomy of the ICA in 2 horses that was identified during treatment for guttural pouch mycosis and identified caudal cerebellar artery infarction as a potential complication of treatment. Because of the size and pathway of both arterial branches, we suggest that the term bifurcation of the ICA is more appropriate than aberrant branching, as has been previously described in the literature. The information in this report may be of value to clinicians performing procedures involving the vasculature of the head and neck in horses.

Comminuted fracture of the accessory carpal bone removed via an arthroscopic-assisted arthrotomy.

A 16-year-old American paint horse gelding was presented for evaluation of a left forelimb lameness grade III/V. Radiographs and computed tomography revealed a comminuted fracture of the accessory carpal bone involving the entire articulation with the distal radius and the proximal aspect of the articulation with the ulnar carpal bone. Multiple fragments were present in the palmar pouch of the antebrachiocarpal joint. An arthroscopic-assisted open approach was necessary to remove all fractured fragments. Subsequently the horse was re-admitted for lameness and was treated successfully with antibiotics and long-term supportive bandaging.

Fracture comminutive de l'os du carpe accessoire enlevé à l'aide d'une arthrotomie assistée par arthroscopie. Un cheval American Paint Horse âgé de 16 ans a été présenté pour l'évaluation d'une boiterie de la jambe avant gauche de grade III/V. Les radiographies et la tomodensitométrie ont révélé une fracture comminutive de l'os du carpe accessoire touchant toute l'articulation avec le radius distal et l'aspect proximal de l'articulation avec l'os du carpe cubital. Des fragments multiples étaient présents dans la poche palmaire de l'articulation antébrachio-carpienne. Une approche ouverte assistée par arthroscopie a été nécessaire pour retirer tous les fragments fracturés. Le cheval a ensuite été réadmis pour boiterie et a été traité avec succès à l'aide d'antibiotiques et de pansements de soutien à long terme.(Traduit par Isabelle Vallières).

Ex vivo equine medial tibial plateau contact pressure with an intact medial femoral condyle, with a medial femoral condylar defect, and after placement of a transcondylar screw through the condylar defect.

OBJECTIVE: To determine ex vivo contact data on the equine medial tibial plateau loaded by an intact medial femoral condyle (MFC), by an MFC with an osteochondral defect, and with a screw inserted in lag fashion through the MFC defect. STUDY DESIGN: Ex vivo experiment. ANIMALS: Stifles (n = 6). Horses (n = 4). METHODS: Stifle joints were axially loaded to 1800 N at 155°, 145°, and 130°, under 3 conditions: Intact, MFC with a 15 mm circular osteochondral defect, and with a transcondylar screw inserted in lag fashion through the defect. An electronic pressure sensor (Tekscan®) on the medial tibial plateau recorded contact area, force, peak pressure, and contact maps. Stress load (N/cm(2) ) was calculated for the entire medial plateau and in 3 sub-regions; cranial, caudal, and central. Significance was set at P ≤ .05. RESULTS: Flexion increased force, contact area, and stress load for all conditions. An MFC defect significantly reduced force at both flexion angles and contact area at 145°. The transcondylar screw returned force to intact values at 130° and reduced contact area in extension. Intact MFC contact maps revealed pressure peaks on the central cartilage at all angles and contact pressure and area expansion and caudal movement with flexion. Contact maps with an MFC defect amplified the caudal and abaxial pressure movement during flexion, and the screw did not further change them. CONCLUSIONS: Stifle flexion increases force, contact area, and stress load on the medial tibial plateau and is most pronounced caudally. An MFC defect alters load on the medial tibial plateau, and a transcondylar screw may reverse some of those changes.