Evaluation of the in vitro performance of the double forwarder knot, compared to square and surgeon's knots using large gauge suture.

OBJECTIVE: The aim of the study was to evaluate the strength and size of the double forwarder (DF) knot in 2 and 3 USP polyglactin 910 when used to form a ligature and to compare the knot holding capacity (KHC), size and weight of the DF knot to surgeon's (SU) and square (SQ) knots with varying numbers of throws. STUDY DESIGN: Laboratory study. STUDY POPULATION: Knotted suture. METHODS: Knots were tied using 2 and 3 USP polyglactin 910 and tested on a universal testing machine under linear tension. Mode of failure and (KHC) were recorded. Knot volume and weight were determined by digital micrometer and balance. KHC, size, and weight between knot type, number of throws, and suture type and size were compared using ANOVA testing, with p < .05 as significant. RESULTS: In both suture types, DF knots had a higher KHC than SQ/SU knots (p < .004), with the exception of SU knots with 6-8 throws in 3 USP polyglactin 910 (p > .42). All DF knots failed by suture breakage at the knot, as did all SQ/SU knots with >6 throws. DF knots in 2 and 3 USP polyglactin 910 were larger and heavier than SQ and SU knots when the same number of throws was applied (p < .003). CONCLUSION: Self-locking DF knots provided increased strength compared to SU/SQ in large gauge suture but only when fewer than six throws are applied to SU/SQ knots. CLINICAL RELEVANCE: The new DF knot could be an alternative for a secure ligature.

Fibro-Osseous Lesions Of The Craniofacial Complex In Horses: 30 Cases (2001-2019).

OBJECTIVE: To describe the presentation, diagnosis, treatment, and outcome for horses with fibro-osseous lesions of the craniofacial complex. STUDY DESIGN: Retrospective multicenter case series. ANIMALS: Thirty horses evaluated for fibro-osseous lesions of the skull from January 1, 2001 through December 31, 2019 in four centers. METHODS: Medical records were reviewed for signalment, clinical presentation, histological and diagnostic imaging findings, treatment instituted, and outcome. Long-term outcome information was obtained by owner questionnaire or the medical record. RESULTS: Diagnoses included ossifying fibroma in 20 of 30 horses, osteoma in eight of 30 horses, and fibrous dysplasia in two of 30 horses. Twelve of 30 lesions were diagnosed in horses <1 year old, and 20 of 30 lesions originated from the rostral mandible. The most common treatment was rostral mandibulectomy. Recurrence was not reported after complete excision. Incomplete excision was confirmed in eight horses (four ossifying fibromas, three osteomas, and one fibrous dysplasia), and follow-up information was available for seven horses. Recurrence occurred in one horse, while six horses had long-term resolution of clinical signs. Prognosis for survival and return to use was excellent in 23 horses with long-term follow-up. CONCLUSION: Fibro-osseous lesions were uncommon in this multicenter study; they were most commonly diagnosed in young animals and most frequently affected the rostral mandible. Long-term survival was excellent. CLINICAL SIGNIFICANCE: The definitive diagnosis of fibro-osseous lesions of the craniofacial complex in horses is made from results of histopathology and cannot be determined on the basis of clinical presentation alone. Surgical excision is indicated, and prognosis can be favorable even when complete surgical margins are not obtained.

Outcome following neurectomy of the deep branch lateral plantar nerve and plantar fasciotomy for hindlimb proximal suspensory desmopathy in western performance horses: 21 cases.

OBJECTIVE: To report the outcome of horses used in western performance disciplines after deep branch lateral plantar neurectomy/fasciotomy surgery for hind limb proximal suspensory desmopathy (PSD). STUDY DESIGN: Retrospective analysis. SAMPLE POPULATION: Twenty-one client-owned horses. METHODS: Medical records were reviewed (2009-2019) for horses involved in western performance disciplines that had been treated with deep branch lateral plantar neurectomy and plantar fasciotomy for lameness due to hind limb PSD. Follow-up was obtained by reexamination and/or verbal interviews with owners >2 years postoperatively. RESULTS: Sixteen quarter horses and five paints were used for western pleasure (14/21), barrel racing (2/21), cutting (1/21), steer wrestling (1/21), working cow horse (1/21), team roping (1/21) and reining (1/21). A median duration of 8 months was required before horses were able to resume training or athletic work. Nine horses were able to return to a similar or higher level of athletic use, nine horses returned to a lower level of athletic performance, and three horses could not return to intended function. Owner satisfaction with outcome after the procedure was high (16/21), average (3/21), and low (2/21). CONCLUSION: Deep branch lateral plantar neurectomy and plantar fasciotomy allowed most horses to resume some athletic function as western performance horses. CLINICAL SIGNIFICANCE: These results provide evidence of potential outcomes when considering surgical treatment of hind limb PSD in western performance horses.

Comparison of analgesic and tissue effects of subcutaneous perineural injection of liposomal bupivacaine and bupivacaine hydrochloride in horses with forelimb lameness induced via circumferential clamp.

OBJECTIVE: To evaluate the analgesic and tissue effects of liposomal bupivacaine administered SC as an abaxial sesamoid nerve block in horses with experimentally induced lameness. ANIMALS: 6 healthy mature light-breed horses. PROCEDURES: In a randomized crossover study, a circumferential hoof clamp was applied to a forelimb to induce reversible lameness. An abaxial sesamoid nerve block of the lame forelimb was performed by SC perineural injection of 10 mg of liposomal bupivacaine or bupivacaine HCl/site. Quantitative gait data were objectively obtained with a body-mounted inertial sensor system before (baseline) and at 30-minute intervals after treatment. Time to return to 85% of baseline lameness was determined. After a minimum 4-day washout period, procedures were repeated with the alternate limb and treatment. Lastly, the palmar digital nerves and perineural tissues were collected and examined histologically. RESULTS: SC perineural injection of liposomal bupivacaine ameliorated forelimb lameness in 5 of 6 horses. The median duration of analgesia was not significantly different between liposomal bupivacaine (4.5 hours) and bupivacaine HCl (3.0 hours). Histologically, mild inflammation was noted in 3 of 10 sites injected with liposomal bupivacaine and in none of the sites injected with bupivacaine HCl. CONCLUSIONS AND CLINICAL RELEVANCE: SC perineural injection of 10 mg of liposomal bupivacaine/site ameliorated experimentally induced forelimb lameness in some horses. At milligram-equivalent doses, liposomal bupivacaine had a similar duration of analgesia to that of bupivacaine HCl. Further investigation is required before recommending clinical use of liposomal bupivacaine for nerve blocks in horses.

Evaluation of Locally Injected Mycobacterium Cell Wall Fraction in Horses with Sarcoids.

A reformulation of Mycobacterium cell wall fraction immunotherapeutic can be used to successfully treat sarcoids in horses. Sarcoids are reported to be the most common equine skin tumors with tumor type and location influencing the choice of treatment. Wide surgical excision is curative for many tumors, but may not always be feasible. Previous studies have reported sarcoid regression after injection with mycobacterial cell wall immunotherapeutics. A new formulation of the Mycobacterium phlei cell wall fraction immunostimulant (Immunocidin Equine) was used to treat cutaneous tumors in horses. Equids with skin tumors diagnosed as sarcoids were enrolled in the study. Sarcoids were injected at the initial visit with Immunocidin Equine and subsequently at approximately 2-week intervals. Of 17 cases, nine cases were completely resolved at the end of the study period evaluation or at the time of final follow-up (52.9%). Three cases were reported as improved (smaller), but not resolved (17.6%). Three cases were discontinued from the study as the respective masses were growing larger or not resolving (17.6%). One case (5.8%) with two masses had resolution of one mass, whereas the other tumor had a small regrowth 5 months after the last treatment. One case (5.8%) was lost to follow-up. All cases had mild to moderate swelling of the injection site, and some cases had discharge after the second, third, or fourth injections. No serious systemic side effects or complications were encountered during the study.

Adaptation and evaluation of a monopolar electrosurgical triangle-tip knife for transendoscopic ventriculocordectomy in healthy horses.

OBJECTIVE: To evaluate the efficacy and safety of a transendoscopic monopolar electrosurgical triangle-tip knife as instrumentation to perform unilateral ventriculocordectomy (VC) in healthy adult horses. STUDY DESIGN: In vivo experimental study. STUDY POPULATION: Nine horses donated for medical conditions unrelated to respiratory system. METHODS: The triangle-tip knife was applied in contact fashion. Left VC was performed under standing sedation. Endoscopic images of the upper airway were graded for inflammation by 2 masked surgeons preoperatively and immediately, 24 hours and, in 2 cases, 7 and 14 days postoperatively. Four larynxes were examined for histological evidence of inflammation and collagen deposition at 24 hours (n = 2) and at 14 days (n = 2) after surgery. RESULTS: Ventriculocordectomy was successfully performed in all horses. Endoscopic evidence of inflammation was scored as normal (preoperatively), mild (immediately postoperatively), mild (24 hours postoperatively), mild (7 days postoperatively), and normal (14 days postoperatively). According to histopathology, inflammation of the surgical site and ventricularis muscle was generally increased (variable is common and is present in most high-power fields) 24 hours and 14 days postoperatively. Fibrosis and collagen deposition also seemed increased at the surgical site 14 days postoperatively. CONCLUSION: Ventriculocordectomy was successfully performed with an electrosurgical triangle-tip knife and resulted in acceptable short-term outcomes. CLINICAL SIGNIFICANCE: The use of an electrosurgical triangle-tip knife alternative instrumentation may be offer an alternative option to perform VC in practices when diode laser is not available or is cost prohibitive. Longer term evaluation of the VC site is required to determine the effect on rima glottic cross-sectional area.

Tenotomy of the semitendinosus muscle under standing sedation versus general anesthesia: Outcomes in 20 horses with fibrotic myopathy.

OBJECTIVE: To compare outcomes after semitendinosus tenotomy performed under standing sedation versus general anesthesia. STUDY DESIGN: Retrospective case series. SAMPLE POPULATION: 20 horses with fibrotic myopathy of the semitendinosus muscle. METHODS: Medical records (2002-2015) of horses undergoing tenotomy of the semitendinosus muscle for the treatment of fibrotic myopathy were reviewed. Signalment, history, affected muscles, restrain method, surgical procedures, and short-term outcome as well as complications were retrieved from records. Long-term outcome (gait and athletic function) was assessed at least 6 months postoperatively by conversation with the owners. Pearson's χ2 statistical analysis was used to compare restrain method and affected muscles with overall outcome. Significance was set at P < .05. RESULTS: Tenotomy of the semitendinosus muscle was performed under standing sedation in 8 horses and under general anesthesia in 12 horses. Follow-up period ranged from 9 months to 10 years. Gait was improved to variable degrees in 8 of 14 horses when the semitendinosus muscle alone was affected and in 4 of 6 horses when both the semitendinosus and semimembranosus muscles were involved (P = .11). Six of 8 horses treated under standing sedation and 6 of 12 horses treated under general anesthesia exhibited some improvement in the characteristic fibrotic gait (P = .4473). Five of 6 athletic horses treated under standing sedation and 6 of 9 athletic horses treated under general anesthesia returned to their preinjury level of athleticism. Horses treated under standing sedation had no incisional complications; 2 of 12 horses treated under general anesthesia exhibited incisional drainage. CONCLUSION: Tenotomy of the semitendinosus muscle in horses with fibrotic myopathy leads to similar improvement in gait, whether performed under standing sedation or general anesthesia.

Efficacy of Teaching the Gambee Suture Pattern Using Simulated Small Intestine versus Cadaveric Small Intestine.

OBJECTIVE: To determine if instruction using simulated small intestine (SSI) is as effective as using cadaveric small intestine to teach the Gambee suture pattern to second year veterinary students. STUDY DESIGN: Prospective, randomized, blinded study. SAMPLE POPULATION: Second year veterinary students (n=59). METHODS: Students were randomly assigned to groups using SSI or equine cadaver small intestine (CSI) to learn the Gambee suture pattern. The same educator, an experienced surgical instructor, instructed all students. Instruction consisted of verbal description of the technique with a schematic diagram followed by a demonstration. Students then practiced the technique with supervision and verbal feedback. One week later, 3 board certified surgeons experienced in surgical instruction evaluated each student suturing equine CSI and scored them using a rubric developed and validated for surgical skills assessment. RESULTS: Fifty-nine students were enrolled (4 students were absent for the lab during which the assessment was performed; 55 students were available for evaluation). Of the 55 students evaluated, 26 were in the SSI group and 29 were in the CSI group. There was no significant difference between CSI and SSI groups in ability to perform the Gambee suture pattern using equine CSI 1 week following training. CONCLUSION: SSI is as effective as equine cadaveric small intestine tissue to teach the Gambee suture pattern to second year veterinary students. If cadaver tissue is unavailable or undesirable, SSI could be used to instruct suture placement techniques.

CD47 expression in cryopreserved equine cutaneous masses and normal skin.

We investigated CD47 expression in cryopreserved sections of equine cutaneous masses and normal skin. CD47 is a cell surface protein expressed on many cell types and overexpressed in some tumors. Interaction of CD47 and signal regulatory protein-alpha (SIRPα) inhibits phagocytosis by macrophages. Formalin-fixed tissues from horses prospectively enrolled in the study were used to establish a histologic diagnosis. Immunohistochemical assays were performed on cryopreserved tissues using anti-CD47 antibodies or IgG control antibodies. CD47 was not expressed on equine normal skin but positivity to CD47 was present in 13 of 24 (54%) masses. Immunotherapy with anti-CD47 antibodies for equine cutaneous tumors that express CD47 warrants further investigation.

Wound care in horses.

Care of equine wounds in the field can be a challenging endeavor. Many times, wound care is complicated by chronicity or by prior inappropriate care in addition to the great degree of tissue trauma that occurred when the horse was wounded. Recognizing involvement of synovial structures, loss of skin, and damage to bone are critical in the initial examination of wounds and will guide future care. Education of clients is also important in that preparing them for possible outcomes during healing may help improve compliance and proper treatment of wound. Owners and trainers often perform much of the daily care and monitoring of equine wounds and thus can greatly assist or impede the progress. Bandaging is important to management of equine wounds-especially on the limbs-and is sometimes overlooked because of its labor-intensive nature and the desire for a spray, ointment, or salve that will heal the wound. The practitioner that improves and utilizes his or her understanding of the wound-healing process in concert with his or her knowledge of local anatomy will be the one who is best equipped to care for wounds in ambulatory practice.

Evidence-based musculoskeletal surgery in horses.

Musculoskeletal disorders comprise a large portion of the conditions treated by equine veterinarians. Surgical intervention is the treatment of choice in many cases. The body of literature describing and exploring surgical correction of musculoskeletal disorders in horses is steadily growing but still lacking. At this juncture, we can use what information we have with the understanding that as the quality of research advances, we should apply stricter standards to the evidence we use to answer our clinical questions.

Effect of hyperimmune plasma on the severity of pneumonia caused by Rhodococcus equi in experimentally infected foals.

This study evaluated the prophylactic effectiveness of hyperimmune plasma (HIP) as an aid in the prevention of pneumonia caused by experimental infection with Rhodococcus equi. Thirty neonatal foals were administered R. equi HIP or saline at 2 days of age and were infected with virulent R. equi at 7 days. All foals developed signs or symptoms of respiratory disease. Radiographic scores on day 28 and neutrophil concentrations on day 49 were significantly greater in control foals, and time to respiratory effort score of 2 or higher was significantly shorter for control foals. Three foals, all in the principal group, died or were euthanized before the end of the study, but there was no significant difference in mortality between groups. VapA titers were significantly greater in principal foals. Administration of R. equi HIP decreased the severity of radiographic lesions and prolonged time to increased respiratory effort due to R. equi-induced pneumonia.

Assessment of the ultrasonographic characteristics of the podotrochlear apparatus in clinically normal horses and horses with navicular syndrome.

OBJECTIVE: To characterize the normal ultrasonographic appearance of the podotrochlear apparatus in horses by use of standardized measurements and identify soft tissue changes associated with navicular syndrome. DESIGN: Prospective study. ANIMALS: 7 clinically normal horses and 28 horses with navicular syndrome. PROCEDURE: The feasibility of identifying and measuring the soft tissue structures of the podotrochlear apparatus ultrasonographically via the transcuneal approach was assessed in 2 additional horses without navicular syndrome; both horses were euthanatized, and the structures identified ultrasonographically were confirmed at necropsy. Ultrasonographs were obtained in the study horses. Objective and subjective data were obtained to characterize ultrasonographic changes associated with navicular syndrome. RESULTS: Abnormalities of the flexor surface of the distal sesamoid (navicular) bone, the impar ligament, the distal digital annular ligament, deep digital flexor tendon (DDFT), and the podotrochlear (navicular) bursa were assessed via the transcuneal ultrasonographic approach. No significant differences were found between the measurements of the podotrochlear apparatus in normal horses and those with navicular syndrome; however, important subjective differences were detected ultrasonographically in horses with navicular syndrome. In horses with navicular syndrome, ultrasonographic findings were indicative of navicular bursitis, dystrophic mineralization of the DDFT and impar ligament, tendonitis and insertional tenopathy of the DDFT, desmitis of the impar ligament, and cortical changes in the flexor surface of the navicular bone. CONCLUSIONS AND CLINICAL RELEVANCE: Findings of ultrasonographic evaluation of the hoof appear to be useful in determining the cause of caudal heel pain and characterizing the components of navicular syndrome in horses.