Brad B. Nelson

In vitro comparison of V‐Loc™ versus Biosyn™ in a one‐layer end‐to‐end anastomosis of equine jejunum

OBJECTIVE To compare a unidirectional barbed suture (V-Loc™) to its suture material equivalent (Biosyn™) in a single-layer end-to-end anastomosis of equine jejunum. STUDY DESIGN Experimental in vitro study. ANIMALS Jejunal sections from adult horses (n = 5) without gastrointestinal disease. METHODS Jejunal end-to-end anastomoses (n = 9) were performed for each group (V-Loc™, Biosyn™) with a continuous Lembert pattern with an interruption every 120°. Anastomosis construction time, luminal diameter, and number of suture bites were recorded. Anastomosis constructs were distended with fluid at 1 L/min until failure. Location and intraluminal pressure at failure were recorded and all measurements were compared between groups. RESULTS V-Loc™ anastomoses were significantly faster to perform (13.1 ± 0.35 minutes) when compared to the Biosyn™ group (15.6 ± 0.72 minutes; P = .0004). No differences were observed for anastomotic index or number of suture bites. V-Loc™ anastomosis constructs had a significantly decreased bursting pressure (160 ± 11.6 mmHg) compared to Biosyn™ constructs (184 ± 16.9 mmHg; P = .01). CONCLUSIONS V-Loc™ allowed faster construction time and did not cause a decreased anastomosis luminal diameter when compared with Biosyn™. V-Loc™ had a decreased bursting strength compared with Biosyn™, albeit well above pathologic pressures encountered clinically. Use of V-Loc™ may be beneficial for decreasing the amount of exposed suture material because of the absence of knots after construction and has the potential to result in decreased adhesions.Objective To compare a unidirectional barbed suture (V-Loc™) to its suture material equivalent (Biosyn™) in a single-layer end-to-end anastomosis of equine jejunum. Study Design Experimental in vitro study. Animals Jejunal sections from adult horses (n = 5) without gastrointestinal disease. Methods Jejunal end-to-end anastomoses (n = 9) were performed for each group (V-Loc™, Biosyn™) with a continuous Lembert pattern with an interruption every 120°. Anastomosis construction time, luminal diameter, and number of suture bites were recorded. Anastomosis constructs were distended with fluid at 1 L/min until failure. Location and intraluminal pressure at failure were recorded and all measurements were compared between groups. Results V-Loc™ anastomoses were significantly faster to perform (13.1 ± 0.35 minutes) when compared to the Biosyn™ group (15.6 ± 0.72 minutes; P = .0004). No differences were observed for anastomotic index or number of suture bites. V-Loc™ anastomosis constructs had a significantly decreased bursting pressure (160 ± 11.6 mmHg) compared to Biosyn™ constructs (184 ± 16.9 mmHg; P = .01). Conclusions V-Loc™ allowed faster construction time and did not cause a decreased anastomosis luminal diameter when compared with Biosyn™. V-Loc™ had a decreased bursting strength compared with Biosyn™, albeit well above pathologic pressures encountered clinically. Use of V-Loc™ may be beneficial for decreasing the amount of exposed suture material because of the absence of knots after construction and has the potential to result in decreased adhesions.

Risk factors associated with gastrointestinal dysfunction in horses undergoing elective procedures under general anaesthesia

REASONS FOR PERFORMING STUDY Gastrointestinal dysfunction occurs commonly following elective anaesthesia. Identification of risk factors may allow implementation of preventative measures to reduce the prevalence of colic following elective anaesthetic procedures. OBJECTIVES To examine risk factors associated with gastrointestinal dysfunction or post anaesthetic colic for horses undergoing elective surgical or diagnostic procedures under general anaesthesia. STUDY DESIGN Retrospective case series. METHODS Medical records were collected from adult horses undergoing general anaesthesia from 1 January 2008 to 31 December 2010 using a retrospective cohort design. Potential risk factors were examined using univariable logistic regression with a limit of a P<0.25. Through backward elimination, the final multivariate model was created to identify variables significantly associated with gastrointestinal dysfunction. RESULTS Colic or delayed faecal output was reported in 36 out of 416 (8.7%) horses undergoing general anaesthesia in the study period. In the final multivariable model, horse breed (P = 0.05), intraoperative peripheral blood lactate (P = 0.02), right lateral recumbency during general anaesthesia (P = 0.04), post anaesthetic rectal temperature (P = 0.03) and hours to first passage of faeces (P<0.01) were statistically significant between horses that exhibited colic compared with those that did not. Arabians were more likely to develop colic compared with other horse breeds (4/13, 30.8%). Horses that exhibited gastrointestinal dysfunction passed faeces later than those that did not (7.2 ± 0.8 h and 5.4 ± 0.2 h, respectively). As blood lactate increased at the end of anaesthesia, the odds of colic occurring also increased (odds ratio:1.4, 95% confidence interval: 1.04-1.83, P = 0.02). CONCLUSIONS This study demonstrated the prevalence of colic in horses undergoing elective general anaesthetic procedures in our hospital population. Arabian horses, increasing blood lactate and delayed passage of faeces were significantly associated with an increased risk of gastrointestinal dysfunction.

COMPARISON BETWEEN COMPUTED TOMOGRAPHIC ARTHROGRAPHY, RADIOGRAPHY, ULTRASONOGRAPHY, AND ARTHROSCOPY FOR THE DIAGNOSIS OF FEMOROTIBIAL JOINT DISEASE IN WESTERN PERFORMANCE HORSES

The femorotibial joints are a common source of lameness in Western performance horses. The objective of this prospective study was to compare the radiography, ultrasonography, computed tomographic arthrography (CTA), and arthroscopy findings in horses with lameness localized to the femorotibial joints. Twenty-five stifles in 24 horses were included and were evaluated with all four of these diagnostic methods. Defects detected in femorotibial joint structures were compared between diagnostic methods using a McNemars test to evaluate for disagreement. Cranial medial meniscotibial desmopathy was most detected on arthroscopy (in 14/25 cases) and was only detected on ultrasonography in three out of 11 (27.3%) arthroscopically observed cases, but was detected on CTA in nine out of 12 (75%) arthroscopically observed cases. Medial meniscal injury located on the craniolateral border was most detected on arthroscopy (n = 9) and was detected on CTA in five cases, but on ultrasonography in 0 cases. Detection of articular cartilage defects on the medial femoral condyle was most detected with arthroscopy (24/25, 96% cases) and was also detected on CTA in 12/20 (60%) cases with a significant disagreement identified between modalities (P = 0.02). Cranial and caudal cruciate ligament defects were detected on CTA in 6/22 (27.3%) and 7/19 (36.8%) cases, respectively, and with arthroscopy in 3/25 (12%) and 2/25 (8%) cases, respectively. The use of CTA detected more defects in the cruciate ligaments, proximal tibia, and ligament entheses than the other diagnostic methods, but was not reliable for detection of articular cartilage damage on the medial femoral condyle.

Use of contrast media in computed tomography and magnetic resonance imaging in horses: techniques, adverse events, and opportunities

The use of contrast media in computed tomography (CT) and magnetic resonance imaging (MRI) is increasing in horses. These contrast-enhanced imaging techniques provide improved tissue delineation and evaluation, thereby expanding diagnostic capabilities. While generally considered safe, not all contrast media exhibit the same safety profiles. The safety of contrast media use and descriptions of adverse events occurring in horses are sparsely reported. This review summarises the reported evidence of contrast media use and adverse events that occur in horses, with added contribution from other veterinary species and studies in man for comparison. This comprehensive data set empowers equine clinicians to develop use and monitoring strategies when working with contrast media. Finally, it summarises the current state-of-the-art and highlights the potential applications of contrast-enhanced CT and MRI for assessment of diseased or injured equine tissues, as well as (patho)physiological processes.

Laparoscopic Closure of the Nephrosplenic Space in Horses with Nephrosplenic Colonic Entrapment: Factors Associated with Survival and Colic Recurrence

OBJECTIVES 1) To identify factors associated with short-term survival and time to death after hospital discharge in horses with nephrosplenic entrapment (NSE). 2) To compare the frequency of recurrent colic episodes in horses with and without laparoscopic closure of the nephrosplenic space. STUDY DESIGN Historical cohort with a nested case control. ANIMALS Client-owned horses. METHODS Medical records of horses treated for NSE from January 1, 2002 to June 1, 2014 were reviewed. Data collected included signalment, physical examination parameters, laboratory results, diagnostic findings, and treatments. Factors associated with short-term survival to discharge were analyzed with a multivariable logistic regression model and time to death after hospital discharge was analyzed with a Cox proportional hazards model. RESULTS During the study period, 211 horses had 231 NSE events and 192/211 (91%) horses survived to discharge. A positive difference in packed cell volume (PCV at admission - PCV after treatment) was associated with reduced odds of nonsurvival with each increment (OR: 0.899, 95% CI 0.816-0.991, P=.03) while the presence of concurrent alimentary lesions (OR: 8.47, 95% CI 1.42-50.4, P=.02) were significantly associated with increased odds of nonsurvival in the short term. Of 156 horses that survived to discharge for which follow-up was available, 152 (97%) were alive for ≥1 year. Increasing age (incremental years) at hospital admission was significantly associated with death after discharge (hazard ratio 1.078, 95% CI 1.002-1.16, P=.049). Recurrence of NSE was documented in 49/211 (23%) horses. The overall change in colic score indicated a reduction in colic in horses following laparoscopic closure of the nephrosplenic space compared with horses that did not have closure of the nephrosplenic space (P<0.001). CONCLUSION An increase in PCV from admission to after treatment and concurrent abdominal lesions were associated with increased odds of nonsurvival to discharge in horses with NSE. Horses that underwent laparoscopic closure had reduced colic episodes compared with horses without laparoscopic closure.

Recent advances in articular cartilage evaluation using computed tomography and magnetic resonance imaging

Articular cartilage is a critical joint tissue and its evaluation remains a diagnostic challenge in horses. Coupled with a poor capacity for healing, early degenerative changes in articular cartilage are difficult to characterise using routine diagnostic imaging evaluations. Both computed tomography (CT) and magnetic resonance imaging (MRI) provide volumetric joint assessment and highlight morphological and quantitative properties of articular cartilage, improving assessment of this essential tissue. While the use of CT and MRI for joint evaluation is not new, there still remains a shortage of literature and scientific studies on the ability of these methods to evaluate articular cartilage in the horse. This review article summarises current CT and MRI techniques capable of characterising equine articular cartilage, highlights recent advances in these techniques and discusses the numerous methods studied in human subjects that have been minimally investigated in horses. Imaging techniques are presented in terms of their capabilities of offering morphological and quantitative evaluation along with a discussion of their benefits and limitations. Finally, it summarises the current state-of-the-art approaches and identifies unmet clinical imaging needs to propel the advancement of articular cartilage and joint imaging in the horse.

Use of a minimally invasive fasciotomy technique for treatment of antebrachial compartment syndrome in two horses

CASE DESCRIPTION An 18-year-old Paint stallion (horse 1) and a 17-year-old Morgan gelding (horse 2) were evaluated because of an acute onset of severe unilateral forelimb lameness. CLINICAL FINDINGS Both horses were unable to bear weight on the affected forelimb and had a dropped elbow appearance. Radial nerve paralysis, triceps myopathy, and fractures of the humerus and ulna were ruled out. The caudal aspect of the affected antebrachium of each horse was very firm to palpation and became firmer when weight was shifted onto the limb. Ultrasonographic examination revealed swelling and suspected intramuscular hemorrhage of the caudal antebrachial muscles. On the basis of clinical examination and diagnostic imaging findings, both horses had antebrachial compartment syndrome diagnosed. Lameness did not substantially improve with medical treatment in either horse. TREATMENT AND OUTCOME Caudal antebrachial fasciotomy was performed in each horse. Following sedation and local anesthetic administration, a bistoury knife was inserted through small incisions to perform fasciotomy. Horses remained standing throughout the procedure and were immediately able to bear weight on the affected limb without signs of discomfort. Horse 1 developed colitis and horse 2 developed a mild incisional infection, but both fully recovered and returned to their previous activities. CLINICAL RELEVANCE Antebrachial compartment syndrome is a rare cause of severe unilateral forelimb lameness and should be considered as a differential diagnosis in horses with a dropped elbow appearance. Both horses of this report had a successful outcome following antebrachial fasciotomy.

Radiofrequency Probe and Sharp Transection for Tenoscopic‐Guided Desmotomy of the Accessory Ligament of the Superficial Digital Flexor Tendon

Objective To compare intra and postoperative clinical features of desmotomy of the accessory ligament of the superficial digital flexor tendon (ALSDFT) using the Saber radiofrequency (SaberRF) electrosurgical probe versus sharp transection with a tenotomy knife. Study Design Randomized, controlled, blocked (horse) design. Animals Adult horses (n = 6). Methods Each horse received bilateral, tenoscopic-guided ALSDFT desmotomy with a SaberRF and tenotomy knife, randomly assigned to left, or right limb. The desmotomy duration and intraoperative hemorrhage grades were recorded. Postoperatively, the grades for surgical incision, carpal sheath effusion, carpal range of motion, flexion pain, and lameness were recorded. Light microscopy using hematoxylin and eosin, and viability staining were performed on the ALSDFT, flexor carpi radialis tendon, radial head of the deep digital flexor tendon, and the deep digital flexor tendon. Variables were compared between desmotomy methods with a paired t-test, Wilcoxon signed rank test, or a repeated measures mixed model. Statistical significance was set at P < .05. Results Desmotomy of the ALSDFT was completed in all horses. Only mild hemorrhage was observed and not different between methods (SaberRF 2/5 limbs; tenotomy knife 5/6 limbs, P = .078). Carpal sheath effusion was greater for SaberRF at Day 1 (P = .019) but not different from tenotomy knife at any later time. There was no significant difference between methods for viability staining or other measured outcomes. Conclusions Tenoscopic-guided ALSDFT desmotomy with the SaberRF probe showed no difference in measured outcomes to sharp transection with a tenotomy knife and minimal collateral tissue damage was observed.OBJECTIVE To compare intra and postoperative clinical features of desmotomy of the accessory ligament of the superficial digital flexor tendon (ALSDFT) using the Saber radiofrequency (SaberRF) electrosurgical probe versus sharp transection with a tenotomy knife. STUDY DESIGN Randomized, controlled, blocked (horse) design. ANIMALS Adult horses (n = 6). METHODS Each horse received bilateral, tenoscopic-guided ALSDFT desmotomy with a SaberRF and tenotomy knife, randomly assigned to left, or right limb. The desmotomy duration and intraoperative hemorrhage grades were recorded. Postoperatively, the grades for surgical incision, carpal sheath effusion, carpal range of motion, flexion pain, and lameness were recorded. Light microscopy using hematoxylin and eosin, and viability staining were performed on the ALSDFT, flexor carpi radialis tendon, radial head of the deep digital flexor tendon, and the deep digital flexor tendon. Variables were compared between desmotomy methods with a paired t-test, Wilcoxon signed rank test, or a repeated measures mixed model. Statistical significance was set at P < .05. RESULTS Desmotomy of the ALSDFT was completed in all horses. Only mild hemorrhage was observed and not different between methods (SaberRF 2/5 limbs; tenotomy knife 5/6 limbs, P = .078). Carpal sheath effusion was greater for SaberRF at Day 1 (P = .019) but not different from tenotomy knife at any later time. There was no significant difference between methods for viability staining or other measured outcomes. CONCLUSIONS Tenoscopic-guided ALSDFT desmotomy with the SaberRF probe showed no difference in measured outcomes to sharp transection with a tenotomy knife and minimal collateral tissue damage was observed.