Comparison of one-layer (continuous Lembert) versus two-layer (simple continuous/Cushing) hand-sewn end-to-end anastomosis in equine jejunum

OBJECTIVE: To evaluate single and double layer end-to-end anastomosis in equine jejunum. STUDY DESIGN: Experimental in vitro study. ANIMALS: Mid-jejunal sections from 12 adult horses without gastrointestinal disease. METHODS: Jejunal end-to-end anastomoses were performed by a continuous Lembert pattern or a simple continuous pattern oversewn with a Cushing pattern. Jejunal segments were distended with fluid at 1 L/min, and intraluminal pressure at failure, and mode of failure were recorded. Bursting pressure and bursting wall tension were calculated. Anastomosis construction time and degree of luminal reduction were recorded. Results- Single layer anastomoses were constructed in less time than 2-layer anastomoses. Both anastomotic techniques resulted in luminal reduction compared with control tissue; however, the reduction was smaller with a 1-layer continuous Lembert anastomosis. No differences were noted in bursting pressure or bursting wall tension between groups. CONCLUSIONS: Anastomosis using a 1-layer continuous Lembert pattern resulted in a larger stoma, was faster to perform, and as strong as a 2-layer anastomosis. CLINICAL RELEVANCE: Use of a 1-layer continuous Lembert pattern for jejunojejunosotomy may be beneficial by decreasing anastomosis time and produce a larger stoma than a 2-layer anastomosis.     

Initial evaluation of a technique for complete cecal bypass in the horse

OBJECTIVE: To describe a novel stapling technique for creation of a complete cecal bypass, without ileal transection in horses. STUDY DESIGN: Experimental study. ANIMALS: Four adult horses. METHODS: Through a ventral median celiotomy, jejunocolostomy was made with an intraluminal anastomosis device (ILA-100) and oversewn with a Cushing pattern to reinforce the staple line. Immediately distal to the anastomosis, 4 rows of staples were applied using a thoracoabdominal stapling device (TA-90) to occlude the lumen of the distal jejunum and proximal ileum. Necropsy exams were performed at least 60 days after surgery. RESULTS: No intraoperative complications occurred. Cecal bypass was functional in all horses at necropsy. The most oral staple line across the ileum partially failed in 1 horse; however cecal bypass was functional. CONCLUSIONS: Complete cecal bypass without ileal transection is a viable alternative to traditional methods of complete cecal bypass. Two sets of staple lines across the ileum are recommended. Longer term follow-up is warranted before clinical use of this technique. CLINICAL RELEVANCE: Cecal bypass without ileal transection is technically simple and effectively bypasses the cecum. It also should intuitively require less time and have a reduced risk of contamination compared with complete cecal bypass with ileal transection.     

In vitro evaluation of an inverted end-to-end equine jejunojejunal anastomosis using skin staples

OBJECTIVE: To compare functional indices of end-to-end (EEA) jejunojejunal anastomosis using skin staples in horses with a 2-layer inverting hand-sewn technique. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Jejunal segments from 8 fresh equine cadavers. METHODS: For each bowel segment, 2 EEA anastomoses were created: one 2-layer hand-sewn and one 1-layer using skin staples. Time for anastomosis creation was recorded and compared. Lumen diameter of each anastomosis was measured on digital radiographs after intraluminal instillation of contrast medium and inflation of the jejunal segments to 14 mm Hg. Anastomotic indices (a compensated measure of stoma diameter) and bursting pressure were determined. RESULTS: EEA jejunal anastomosis using skin staples was significantly faster than use of a 2-layer hand-sewn technique. Anastomotic index, a measure of lumen size, was significantly larger with the skin-staple technique; however, the bursting pressure of stapled anastomoses was significantly less than for the hand-sewn technique, but the values were well above those reported for other anastomotic techniques. CONCLUSIONS: An anastomotic technique using skin staples was easy to learn and perform, effective and faster, and mechanically comparable with a hand-sewn 2-layer technique. CLINICAL RELEVANCE: The staple technique could be beneficial in equine gastrointestinal surgery by reducing anastomosis time, although further in vivo studies are needed to establish clinical safety.     

In vitro assessment of movements of the sacroiliac joint in the horse

REASONS FOR PERFORMING STUDY: Sacroiliac joint (SIJ) disease is associated with poor hindlimb action, lameness and poor performance in horses. However, little is known about the biomechanics of this low-motion joint. OBJECTIVES: To determine in vitro the capacities of movement of the SIJ in the sagittal plane, and to test the effect of a sacrosciatic and sacrotuberal desmotomy on its stabilisation. METHODS: Six anatomical specimens underwent cycles of flexion-extension of the lumbosacral joint (LSJ) before and after desmotomy. Kinematic triads were linked rigidly to the sacrum, spinous process of vertebra L5 and iliac wing. Angles were measured using a joint coordinate system based on anatomical frames. RESULTS: The LSJ underwent regular movements of flexion and extension (overall mean +/- s.d. range 23.4 +/- 1.6 degrees). The only recorded movement of the SIJ was a nutation during LSJ flexion (overall mean +/- s.d. 0.8 +/- 0.5 degrees). Desmotomy induced an increase of that nutation (overall mean +/- s.d. 1.7 +/- 0.2 degrees). CONCLUSIONS AND POTENTIAL RELEVANCE: Movements of the SIJ were small and coupled only with the flexion of the LSJ. The ligaments surrounding the SIJ have a strong effect on the stabilisation of this joint. Due to the limited amount of movement, its biomechanical study in vivo seems to be difficult. Further in vitro studies would be useful to determine the role of each ligament, to better understand the clinical consequences of the tears frequently observed during necropsy.     

Comparison of suture materials and suture patterns for inverting intestinal anastomosis of the jejunum in the horse

In 7 horses, 4 anastomoses were done in the small intestine in each, using the combinations of synthetic absorbable monofilament and multifilament suture materials with continuous- and interrupted-suture patterns in the serosubmucosal layer of a 2-layer inverting-suture technique. Horses were evaluated 30 days after the operation for adhesion formation, lumen diameter, evidence of chronic obstruction, and suture tract inflammation at the anastomosis. Postoperative obstruction occurred in 5 of the 7 horses, and 6 horses survived. One horse was euthanatized on postoperative day 6 after 48 hours of ileus and obstruction; necropsy revealed a partial intussusception involving the anastomosis done with continuous multifilament-suture material. Two other horses that became obstructed between postoperative days 3 and 5 had protracted ileus and gastric reflux up to 48 hours' duration, but survived. Horses that had obstruction after the 6th postoperative day recovered within 4 hours of onset. The continuous inverting-suture pattern in the serosubmucosal layer resulted in significantly (P less than 0.05) fewer adhesions than did the interrupted pattern, and suture material had no effect on adhesion formation. There was no significant difference in the percentage of reduction of lumen diameter between the variations of the 2-layer technique, and there was no evidence of chronic obstruction related to any of the anastomoses. Suture tract inflammation was moderate in the anastomoses, using continuous-multifilament suture, with neutrophils being the predominant cell type. The anastomoses with continuous-monofilament suture had mild inflammation with focal accumulations of neutrophils. Minimal inflammation was associated with both types of suture in the interrupted pattern.     

In vitro effects of tachykinins on the smooth musculature of horse gut

The contractile effects of the tachykinins eledoisin, substance P and neurokinin A and B were investigated in vitro on circular and longitudinal muscle strips from horse duodenum, ileum and colon. Circular smooth muscle of the small intestine was highly responsive, large intestine circular smooth muscle less so, while longitudinal muscle from all gut segments was much less sensitive. pD₂ values and intrinsic activities on small intestine circular muscle indicated differences in receptor distribution between the duodenum and ileum: NK₃ and a smaller number of NK₂ receptors being present in the duodenum, and NK₂ receptors predominating in the ileum. Notwithstanding this, eledoisin and neurokinin B were the most active substances on duodenum and ileum, respectively. These findings suggest that tachykinins may play a role in equine gastrointestinal pathophysiology.     

In vitro evaluation of porcine lymphocyte response to phytohaemagglutinin using a modified “whole blood” technique

The purpose of these investigations was to develop a modified whole blood technique for measuring quantitatively the responsiveness of pig peripheral blood lymphocytes to phytohaemagglutinin (PHA) in vitro. Washed blood cells from a fixed volume of blood were suspended in culture medium supplemented with foetal calf serum and stimulated with a pure mitogenic PHA preparation. The stimulation was measured by the incorporation of ³H-thymidine.Data are presented to show the effect of different variables on the culture system. The transformation response was measured at different levels of PHA and the reproducibility of the different responses from repeated investigations was used to evaluate the usefulness of the test.The best reproducibilities of the stimulation response were found at the high PHA concentrations.Also the calculated PHA concentration giving maximum stimulation response had a relatively high reproducibility and indicates that this value is a convenient and reliable alternative measure of the functional capacity of the lymphocytes.     

A technique for assessing hoof function in the horse

This paper describes the application of foil strain gauges to the hoof wall, and the use of measuring equipment to monitor weightbearing and changes in hoof shape in shod and unshod horses. It concludes that the systems can detect hoof movement and that results are reproducible. It is also concluded that the use of a conventional nailed on iron shoe restricts flexion and spreading of the hoof wall at the ground surface, but has little effect on the degree of expansion of the heels of the foot.     

A technique for pelvic radiography in the standing horse

REASONS FOR PERFORMING STUDY: An alternative technique of radiographing the pelvis in the standing horse is required, to avoid the risks associated with general anaesthesia. HYPOTHESIS: That lateral oblique radiography in the standing horse would be a useful technique in the investigation of pelvic injury. OBJECTIVES: To describe the technique of lateral oblique pelvic radiography in the standing horse and demonstrate the feasibility and usefulness of this technique. METHODS: A technique for lateral oblique radiography in the standing horse was devised and retrospective review made of radiographic findings in 18 clinical cases. RESULTS: The caudal iliac shaft, greater trochanter of the femur, femoral head, acetabulum and coxofemoral articulation on the side under investigation were visualised consistently using this technique. Of the 18 cases, 3 iliac shaft fractures, 1 acetabular fracture, 2 coxofemoral luxations and 4 horses with new bone formation around the coxofemoral joint and/or proximal femur were identified. CONCLUSIONS: Lateral oblique radiography in the standing, conscious horse can be used to investigate conditions affecting the caudal iliac shaft, coxofemoral articulation and proximal femur in the horse. POTENTIAL RELEVANCE: The technique is straightforward, noninvasive and useful in the investigation of horses with suspected pelvic injury. However, not all pelvic injuries would be identified, and normal radiographic findings do not rule out injury or fractures elsewhere in the pelvis.     

In vitro evidence for effects of magnesium supplementation on quinolone-treated horse and dog chondrocytes

Quinolones and magnesium deficiency cause similar lesions in joint cartilage of young animals. Chondrocytes cultivated in the presence of quinolones and in Mg-free medium show severe alterations in cytoskeleton and decreased ability to adhere to the culture dish. We investigated whether Mg2+ supplementation can prevent quinolone-mediated effects on chondrocytes in vitro. Chondrocytes cultivated in Dulbecco's modified Eagle's medium/HAM's F-12 medium were treated with ciprofloxacin (80 and 160 microg/ml) and enrofloxacin (100 and 150 microg/ml). Mg2+ was added at a concentration of 0.0612 mg/ml (MgCl) and 0.0488 mg/ml (MgSO4) or a triple dose. In addition, cells were cultivated in Mg-free medium and accordingly treated with Mg2+ supplementation. After 5 days in culture, the number of adherent cells per milliliter was determined. The number of chondrocytes in quinolone-treated groups decreased to 12-36% that of the control group within the culture period. With Mg2+ supplementation, the number of attached cells increased to 40-70% that of control cells. The threefold dose of Mg2+ led to better results than did the single dose. Cell proliferation tested by immunohistochemical staining with Ki67 (clone MIB5) decreased from 70% in control groups to 55%, 48%, and 30% in enrofloxacin-treated groups in a concentration dependent manner (50, 100, and 150 microg/ml). Addition of Mg2+ did not increase the rate of cell proliferation. These results suggest that a great part of quinolone-induced damage is due to magnesium complex formation, as Mg2+ supplementation is able to reduce the effects in vitro. However, quinolone effects on cell proliferation seem to be an independent process that is not influenced by magnesium supplementation.     

In vitro evaluation of frozen-thawed stallion semen: a review

The article reviews methods used for in vitro evaluation of sperm, with particular emphasis on frozen-thawed stallion sperm. The techniques, limitations of the methods and correlations with fertility results are discussed. Very few studies have tried to find correlation between fertility of frozen stallion semen and laboratory tests. It is difficult and expensive to inseminate an adequate number of mares to achieve statistically significant differences. Significant, but low correlations have been demonstrated between the foaling rate and subjective motility of sperm incubated for 2 h and 4 h at 37 degrees C and hypoosmotic swelling test after 0 and 3 h of incubation. Significant correlations have been reported between the pregnancy rate and viability of propidium iodide-stained sperm assessed by flow cytometry as well as for glass wool and Sephadex filtration tests. No correlations have been detected between fertility and motility immediately after thawing. In spite of that, motility estimation by light microscope is the most commonly used method to evaluate frozen-thawed stallion sperm. Computer assisted automatic sperm analyzers have replaced light microscopy in research projects, but so far nobody has been able to demonstrate a correlation between fertility of frozen stallion semen and any of the motility parameters obtained by these instruments.     

In vitro evaluation of nonrigid support systems for the equine metacarpophalangeal joint

Metacarpophalangeal (MCP) joint extension is primarily resisted by the digital flexor tendons and suspensory ligament. A variety of external support techniques are used to protect these supporting structures from or after injury by resisting MCP joint extension, although not all are effective and/or practical for use in an exercising horse. In this study, 7 forelimbs were loaded in vitro to determine the effect of a simple gamgee bandage, a 3-layered bandage with and without a contoured palmar splint, a neoprene exercise boot, and an innovative carbon fibre composite exercise boot (Dalmar tendon support boot). There was no significant resistance to MCP joint extension by the gamgee or neoprene exercise boot. The 3-layered bandage had a significant (P<0.01) supporting effect at MCP angles of > or = 245 degrees, and when combined with the contoured splint at angles of > or = 230 degrees. The Dalmar tendon support boot resisted MCP extension at angles of > or = 245 degrees (settings 1 and 2) and > or = 225 degrees (setting 3). These data demonstrate that the contoured splint and the Dalmar tendon support boot (which is also easily fitted for use during exercise) are useful for the management of tendon/ligament injury and during rehabilitation.     

Use of computed tomography angiography for the evaluation of a cutaneous haemangioma in a Standardbred horse

Cutaneous haeangiomas are benign vascular neoplasms that arise from endothelial cells of blood vessels. Haemangiomas account for 0.6%–4% of all equine cutaneous neoplasms and the fetlock is the most commonly affected site. We describe the use of computed tomography angiography (CTA) for the evaluation of a cutaneous haemangioma located on the plantarolateral aspect of the left hindlimb fetlock of a 9-month-old Standardbred colt. Computed tomography angiography of the affected fetlock was performed under general anaesthesia. The medial plantar artery was catheterised and a total volume of 50 ml of iodinated non-ionic contrast medium (Iopamidol, 300 mg I/ml, Bracco Imaging Canada) was injected at a rate of 2 ml/s. Following contrast medium administration, the dorsal metatarsal artery and branches including the lateral and medial digital arteries were well demarcated. Two smaller lateral and medial arteries were also identified, forming the vascular network of the metatarsophalangeal joint. At the level of the haemangioma, two tortuous arteries arising from the lateral digital artery were identified, in addition to multiple small branches from nearby cutaneous arteries. These vessels supplied the homogeneously strongly contrast-enhancing cutaneous mass. The initial goal of the CTA study was to map the vascular anatomy for arterial embolisation in conjunction with pharmacological therapy. Considering the involvement of multiple small arterial branches, complete surgical excision along with ligation of the two main supplying arteries was alternatively elected, resulting in a successful long-term outcome.     

A new technique for accessing the cerebral ventricles of the horse

A technique is described for catheterisation of the ventricular recess within the olfactory bulb of the horse. Twelve adult horses were used. The olfactory recess is in the frontal region, 42±3 mm below the skin, on the line joining the supraorbital foramina, and approximately 18±2 mm from the midline. The approach is relatively easy under normal experimental conditions.