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.

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.

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.

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.

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.

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.

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.

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.

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 t_0, t_15, t_30, t_60, t_90, t₁₂₀ and t_180 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.

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.

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.

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.

Validation of a 2-mm videoendoscope for the evaluation of the paranasal sinuses with a minimally invasive technique

OBJECTIVE

To describe the technique, experience, and limitations of using a 2-mm flexible endoscope to perform standing minimally invasive sinoscopy.

STUDY DESIGN

In phases 1 and 2, we used cadaveric heads (ex vivo). In phase 3, we used unaffected horses (in vivo).

ANIMALS

Five cadaveric equine skulls in phase 1 and 10 cadaveric equine skulls in phase 2. Six horses older than 5 years in phase 3.

METHODS

In phase 1, the specimens were used to determine the suitability of the endoscope for sinoscopy and the ideal landmarks to approach the paranasal sinuses through minisinusotomies performed with a 14 gauge needle. In phase 2, a nonblinded evaluation of the visualization of the different sinus compartments was performed, and a score was attributed to each structure. Procedures were video recorded and compared with direct visualization of the sinuses after performing frontal and maxillary flaps. In phase 3, the technique was validated in healthy horses under sedation.

RESULTS

The landmarks determined in phase 1 allowed a thorough exploration of the sinuses in phases 2 and 3. Sinoscopy findings were confirmed after direct visualization of the sinuses via frontal and maxillary bone flaps in phase 2. The procedure was well tolerated by all horses.

CONCLUSION

Minimally invasive sinoscopy was readily performed without relevant complications in standing horses. A thorough evaluation of most sinus structures was obtained only using the frontal and the rostral maxillary portals.

CLINICAL SIGNIFICANCE

Minimally invasive sinoscopy offers an alternative diagnostic tool to veterinarians. A specialized endoscope and appropriate training are required to perform this minimally invasive 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.

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.

Minimally invasive repair of a calcaneus fracture in a Standardbred foal

CASE DESCRIPTION

A 4-month-old Standardbred colt was examined because of a fractured right calcaneus of 8 days' duration with increased distraction of the fracture fragment evident on sequential radiographs.

CLINICAL FINDINGS

The foal was severely lame with diffuse periarticular tarsal swelling. Radiographically, a complete, displaced long oblique fracture of the right calcaneal body was evident. Because the fracture gap was increasing with time and lameness remained severe, despite medical management, surgical repair was recommended.

TREATMENT AND OUTCOME

The foal was anesthetized, and minimally invasive fracture reduction and internal fixation were achieved by use of two 4.5-mm cortical screws placed in lag fashion via stab incisions over the lateral aspect of the calcaneus. External coaptation with a Robert-Jones bandage only was used after surgery. The foal recovered well and the fracture healed appropriately, but at 8 weeks following surgery, tenosynovitis of the tarsal sheath had developed. This was attributed to the tip of the distal screw encroaching on the sheath. The screw was removed under anesthesia and the tarsal sheath drained. The tenosynovitis resolved with rest and bandaging. Fourteen months after surgery, the colt was free of lameness.

CLINICAL RELEVANCE

Findings suggested that a minimally invasive internal fixation technique for treatment of a calcaneus fracture in horses may be successful and may be associated with decreased morbidity, compared with the use of open reduction and plate fixation.