Andrea S. Bischofberger

Magnetic resonance imaging, ultrasonography and histology of the suspensory ligament origin : a comparative study of normal anatomy of Warmblood horses

REASONS FOR PERFORMING STUDY The diagnosis of lameness caused by proximal metacarpal and metatarsal pain can be challenging. Magnetic resonance imaging (MRI) offers the possibility for further diagnosis but there have been no studies on the normal MRI appearance of the origin of the suspensory ligament (OSL) in conjunction with ultrasonography and histology. OBJECTIVES To describe the MRI appearance of the OSL in fore- and hindlimbs of sound horses and compare it to the ultrasonographic and histological appearance. The findings can be used as reference values to recognise pathology in the OSL. METHODS The OSL in the fore- and hindlimbs of 6 sound horses was examined by ultrasonography prior to death, and MRI and histology post mortem. Qualitative evaluation and morphometry of the OSL were performed and results of all modalities compared. RESULTS Muscular tissue, artefacts, variable SL size and shape complicated ultrasonographic interpretation. In MRI and histology the forelimb OSL consisted of 2 portions, the lateral being significantly thicker than medial. The hindlimb SL had a single large area of origin. In fore- and hindlimbs, the amount of muscular tissue was significantly larger laterally than medially. Overall SL measurements using MRI were significantly higher than using histology and ultrasonography and histological higher than ultrasonographic measurements. Morphologically, there was a good correlation between MRI and histology. CONCLUSIONS MRI provides more detailed information than ultrasonography regarding muscle fibre detection and OSL dimension and correlates morphologically well with histology. Therefore, ultrasonographic results should be regarded with caution. POTENTIAL RELEVANCE MRI may be a diagnostic aid when other modalities fail to identify clearly the cause of proximal metacarpal and metatarsal pain; and may improve selection of adequate therapy and prognosis for injuries in this region.

Difference in incisional complications following exploratory celiotomies using antibacterial-coated suture material for subcutaneous closure: Prospective randomised study in 100 horses

REASONS FOR PERFORMING STUDY Incisional complications are a major post operative challenge following ventral midline exploratory celiotomy for abdominal pain in horses. They lead to discomfort, prolonged hospitalisation, longer recovery times and increased cost; therefore, investigation of preventative procedures are warranted. OBJECTIVES To determine the clinical effect of antibacterial (triclosan) coated 2-0 polyglactin 910 suture material on the likelihood of incisional infections when used for closure of subcutaneous tissue following ventral midline celiotomies in horses. METHODS One hundred horses undergoing exploratory celiotomy assigned at random to one of 2 groups. In the control group coated 2-0 polyglactin 910 (Vicryl) was used for apposition of the subcutaneous tissue in a simple continuous pattern and, in the study group, antibacterial (triclosan) coated 2-0 polyglactin 910 suture material (Vicryl Plus) was used. Post operatively an elastic adhesive abdominal bandage was applied, changed and the incision was inspected by a clinician blinded to the study protocol at 24-36 h and 6-9 days post operatively. Outcomes of interest were evidence of incisional pain, incisional oedema, sheath/udder oedema, incisional drainage, hernia formation and dehiscence. RESULTS Antibacterial-coated suture material did not decrease the likelihood of incisional complications in 100 horses. CONCLUSIONS A beneficial effect on ventral midline incisions in 100 horses was not evident by using antibacterial-coated suture material. POTENTIAL RELEVANCE Lack of effectiveness of antibacterial-coated suture material in equine ventral midline closure after exploratory celiotomy and the observed potential adverse effects suggest that further clinical investigations are needed before using such material routinely on horses.

A Preliminary Study on the Effect of Manuka Honey on Second‐Intention Healing of Contaminated Wounds on the Distal Aspect of the Forelimbs of Horses

OBJECTIVE To determine the effect of manuka honey on second-intention healing of contaminated, full-thickness skin wounds in horses. STUDY DESIGN Experimental. ANIMALS Adult Standardbred horses (n = 8). METHODS One wound was created on the dorsomedial aspect of the third metacarpus in both forelimbs, contaminated with feces, and bandaged for 24 hours. Bandages were removed and wounds rinsed with isotonic saline solution. Wounds on 1 limb had manuka honey applied daily (n = 8) whereas wounds on the contralateral limb received no treatment (n = 8). Bandages were replaced and changed daily for 12 days, after which treatment stopped, bandages were removed, leaving wounds open to heal. Wound area was measured 24 hours after wound creation (day 1), then weekly for 8 weeks. Overall time for healing was recorded. Wound area and rate of healing of treated and control wounds were compared statistically. RESULTS Treatment with manuka honey decreased wound retraction and treated wounds remained significantly smaller than control wounds until day 42; however, there was no difference in overall healing time between treatment and control wounds. CONCLUSIONS Treatment with manuka honey reduced wound area by reducing retraction but did not affect overall healing time of full-thickness distal limb wounds using this wound-healing model.

Surgical management of complete diaphyseal third metacarpal and metatarsal bone fractures: Clinical outcome in 10 mature horses and 11 foals

REASONS FOR PERFORMING STUDY Osteosynthesis of third metacarpal (McIII) and third metatarsal (MtIII) bone fractures in horses is a surgical challenge and complications surrounding the repair are common. Retrospective studies evaluating surgical repair, complications and outcome are necessary to increase knowledge and improve success of long bone fracture repair in the horse. OBJECTIVES To evaluate clinical findings, surgical repair, post operative complications and outcome of 10 mature horses and 11 foals with McIII or MtIII fractures that were treated with open reduction and internal fixation (ORIF). METHODS Medical records were reviewed and follow-up information obtained by means of radiographs and/or telephone questionnaire. RESULTS Survival was achieved in 62% of the horses (3 mature/10 foals). On long-term evaluation (> 6 months) 11 horses (2 mature/9 foals) were fit for their intended activity, one mature horse had a chronic low grade lameness, and one foal was lost to follow-up because it was sold. The main fracture types were simple transverse (333%) or simple oblique (28.6%) and 71.4% of the fractures were open, 3 Type I (one mature/2 foals) and 12 type II (7 mature/5 foals). The preoperative assessment revealed inadequate emergency treatment in 10 horses (5 mature/5 foals; 47.6%). Survival rate of horses with open fractures was 12.5% (1/8) in mature and 85.7% (6/7) in foals. Post operative incisional infection (4 mature, 3 foals) was only managed successfully in 2 foals. Fracture instability related to inadequate fracture fixation technique occurred in 4 horses (all mature) and was always associated with unsuccessful outcome. CONCLUSIONS Age, bodyweight and infection are strongly associated with outcome in treatment of complete McIII/MtIII fractures. CLINICAL RELEVANCE Rigid fixation using plates and screws can be successful in treatment of closed or open, complete diaphyseal McIII/MtIII fractures in mature horses and foals. Instable fixation, infection and a bodyweight > 320 kg are major risk factors for unsuccessful outcome.

Effect of Manuka honey gel on the transforming growth factor β1 and β3 concentrations, bacterial counts and histomorphology of contaminated full-thickness skin wounds in equine distal limbs

OBJECTIVE To investigate the effect of 66% Manuka honey gel on the concentrations of transforming growth factor (TGF)-β1 and TGF-β3, bacterial counts and histomorphology during healing of contaminated equine distal limb wounds. METHODS In this experimental study of 10 Standardbred horses, five full-thickness skin wounds (2 × 1.5 cm) were created on one metacarpus and six similar wounds were created on the contralateral metacarpus. Wounds were assigned to three groups: non-contaminated control wounds; contaminated control wounds; contaminated wounds treated daily with 1 mL Manuka honey gel topically for 10 days. For the contaminated wounds, faeces were applied for 24 h after wound creation. In five horses wounds were bandaged and in the other five horses wounds were left without a bandage. Biopsies were taken on days 1, 2, 7 and 10 after wounding to evaluate the effects of Manuka honey gel, wound contamination and bandaging on TGF-β1 and TGF-β3 concentrations, aerobic and anaerobic bacterial counts, and histomorphology. RESULTS Manuka honey gel had no significant effect on TGF-β1 and TGF-β3 concentrations or wound bacterial counts. Manuka honey gel decreased wound inflammation (days 7, 10), increased angiogenesis (days 2, 7, 10), increased fibrosis and collagen organisation (day 7) and increased epithelial hyperplasia (days 7, 10). CONCLUSIONS Treatment with Manuka honey gel resulted in a more organised granulation tissue bed early in wound repair, which may contribute to enhanced healing of equine distal limb wounds.

Ocular angiosarcoma in a pony - MRI and histopathological appearance

Ocular angiosarcomas are an infrequent aetiology of exophthalmus in the horse. In the case presented here, a pony was referred with a history of supraorbital swelling, exophthalmus and conjunctivitis of the right eye. Radiographic and ultrasonographic examinations were used for diagnosis; however, the exact definition of the retrobulbar changes could only be made by magnetic resonance imaging (MRI). MRI shows anatomic and physiological detail in both the osseous and soft tissue structures. Only 3 sequences were used in this case: a transverse T2-weighted and a dorsal high resolution, T1-weighted gradient echo with multiplanar reconstruction capability pre- and post contrast application. This case report suggests that MRI should be used more frequently in the diagnosis of head tumours in horses.

Effects of intra‐articular sodium pentosan polysulfate and glucosamine on the cytology, total protein concentration and viscosity of synovial fluid in horses

OBJECTIVE Evaluate synovial fluid cytology, total protein concentration and viscosity after intra-articular administration of combined pentosan polysulfate and glucosamine in horses. DESIGN Ten adult Standardbred horses had each carpal joint (n = 20) randomly assigned to one of two treatments: control (5 mL saline) or treated (pentosan polysulfate and glucosamine). All horses received an intra-articular injection every 7 days for 3 weeks and synovial fluid samples were collected on days 1 (baseline), 2, 3, 7, 8, 9, 14, 15, 16 and 21. Synovial fluid variables measured included total protein concentration, total nucleated cell count, red blood cell count, the neutrophil, lymphocyte, mononuclear cell and eosinophil percentages, and viscosity. RESULTS Following injection, the total nucleated cell count increased in the synovial fluid samples from both groups. Values were significantly higher in treated joints on days 2, 3, 15 and 16. Red blood cell counts were low and no differences were seen between treated and control joints. Total protein concentrations and neutrophil percentages increased in both groups after injection, but decreased towards normal ranges within 7 days. Total protein concentration was significantly higher in treated joints on days 1, 3, 8, 9 and 15. Percentages of neutrophils were higher in treated joints on day 2, but significantly lower on days 8 and 15. Viscosity was significantly higher in treated joints on day 2 only. CONCLUSIONS Intra-articular administration of combined pentosan polysulfate and glucosamine causes a mild inflammatory synovitis that is not substantially different to that elicited by injection of a similar volume of saline and so we conclude that these drugs are safe to use in the horse.

Optimal Tension, Position, and Number of Prostheses Required for Maximum Rima Glottidis Area After Laryngoplasty

OBJECTIVES To evaluate the effect of 3 laryngeal prostheses alone or in combination on rima glottidis area in horses. STUDY DESIGN Experimental randomized design. SAMPLE POPULATION Cadaveric equine larynges (n = 22). METHODS Three prostheses were preplaced in each of 14 larynges. Rima glottidis area was measured after loading each suture in 5 Newton (N) increments from 0 N to 35 N. In 8 larynges, the 3 prostheses were tied alone or in combination at a fixed load of 15 N and rima glottidis area measured. RESULTS Rima glottidis cross-sectional area increased as the load on each prosthesis increased with maximum area reached at 20 N for each prosthesis. At a fixed load of 15 N, tying 2 and 3 prostheses in combination resulted in a larger rima glottidis cross-sectional area than achieved with each prosthesis alone. CONCLUSIONS A combination of 2 or 3 prostheses tied at a fixed load of 15 N optimized rima glottidis cross-sectional area irrespective of the anatomic location of the prosthesis.

Effect of activated protein C in second intention healing of equine distal limb wounds: a preliminary study

OBJECTIVE To investigate the effect of activated protein C (APC) on second intention healing of distal limb wounds in horses. METHODS In this experimental study of eight Standardbred geldings, six full-thickness skin wounds (2 × 1.5 cm) were created on one metacarpus (biopsy limb) and five similar wounds were created on the contralateral metacarpus (photographed limb). Three wounds on the biopsy limb were treated topically with 190 µg APC on days 1, 3, 6 and 9, while the remaining three wounds were untreated (control). One treated and one control wound were biopsied on days 4, 7 and 11 for histopathology. Wounds on the photographed limb were treated with either 66% Manuka honey gel, a commercial antibiotic ointment (bacitracin-neomycin-polymixin B ointment; BNP) or petrolatum daily throughout healing, treated on days 1,3,6 and 9 with 190 µg APC or left untreated. These wounds were digitally photographed and the wound area measured on day 1, then weekly until day 49. Overall time to healing was recorded. RESULTS There was no effect of APC on wound size, the rate of healing or the overall time to heal. However, compared with control wounds, histological scoring demonstrated enhanced epithelialisation (day 4) and angiogenesis (day 11). Wound healing variables for wounds treated with APC, Manuka honey gel and control wounds were not different and the variables for wounds treated with BNP and petrolatum demonstrated delayed healing. CONCLUSION The improvements in histological scores in APC-treated wounds suggest further study into the effect of APC on second intention wound healing in horses is warranted.

Erkrankungen im Bereich des Fesselträgerursprungs beim Pferd: Eine diagnostische Herausforderung

Lameness in horses due to pain originating from the proximal metacarpal/metatarsal region remains a diagnostic challenge. In cases of obvious lameness the pain can be localised to this region by diagnostic anaesthesia. Because a variety of disorders can cause lameness in this region different imaging modalities including radiography, ultrasonography and scintigraphy should be used to arrive at an accurate diagnosis. Even though a precise anatomic-pathologic diagnosis can still be an enigma, because not only bone and joints, but also soft tissue structures including the proximal suspensory ligament, its origin at the proximal metacarpus/ metatarsus, its fascia, the superficial fascia, as well as the intermetacarpal/metatarsal ligaments, the accessory ligament of the deep digital flexor tendon and both digital flexor tendons may be involved. Magnet resonance tomography (MRT) shows a high diagnostic sensitivity in imaging soft tissue structures and bone. In horses MRT is still at the beginning. The MRT appearance of the proximal metacarpal/metatarsal region has not yet been evaluated in detail and there are only few anatomic studies of the origin of the suspensory ligament in horses. The first experiences showed, that more gross and histologic examinations are necessary to fully interpret MRT-images and to differentiate pathologic alterations from clinically not relevant variations.