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.

Lipolysis inhibition as a treatment of clinical ketosis in dairy cows: A randomized clinical trial.

Excessive and protracted lipolysis in adipose tissues of dairy cows is a major risk factor for clinical ketosis (CK). This metabolic disease is common in postpartum cows when lipolysis provides fatty acids as an energy substrate to offset negative energy balance. Lipolysis in cows can be induced by the canonical (hormonally induced) and inflammatory pathways. Current treatments for CK focus on improving glucose in blood (i.e., oral propylene glycol [PG], or i.v. dextrose). However, these therapies do not inhibit the canonical and inflammatory lipolytic pathways. Niacin (NIA) can reduce activation of the canonical pathway. Blocking inflammatory responses with cyclooxygenase inhibitors such as flunixin meglumine (FM) can inhibit inflammatory lipolytic activity. The objective of this study was to determine the effects of including NIA and FM in the standard PG treatment for postpartum CK on circulating concentrations of ketone bodies. A 4-group, parallel, individually randomized trial was conducted in multiparous Jersey cows (n = 80) from a commercial dairy in Michigan during a 7-mo period. Eligible cows had CK symptoms (lethargy, depressed appetite, and milk yield) and hyperketonemia (blood ß-hydroxybutyrate [BHB] ≥1.2 mmol/L). Cows with CK were randomly assigned to 1 of 3 groups where the first group received 310 g of oral PG once per day for 5 d; the second group received PG for 5 d + 24 g of oral NIA once per day for 3 d (PGNIA); and the third group received PG for 5 d + NIA for 3 d + 1.1 mg/kg i.v. FM once per day for 3 d (PGNIAFM). The control group consisted of cows that were clinically healthy (HC; untreated; BHB <1.2 mmol/L, n = 27) matching for parity and DIM with all 3 groups. Animals were sampled at enrollment (d 0), and d 3, 7, and 14 to evaluate ketone bodies and circulating metabolic and inflammatory biomarkers. Effects of treatment, sampling day, and their interactions were evaluated using mixed effects models. Logistic regression was used to calculate the odds ratio (OR) of returning to normoketonemia (BHB <1.2 mmol/L). Compared with HC, enrolled CK cows exhibited higher blood concentrations of dyslipidemia markers, including nonesterified fatty acids (NEFA) and BHB, and lower glucose and insulin levels. Cows with CK also had increased levels of biomarkers of pain (substance P), inflammation, including lipopolysaccharide-binding protein, haptoglobin, and serum amyloid A, and proinflammatory cytokines IL-4, MCP-1, MIP-1α, and TNFα. Importantly, 72.2% of CK cows presented endotoxemia and had higher circulating bacterial DNA compared with HC. By d 7, the percentage of cows with normoketonemia were higher in PGNIAFM = 87.5%, compared with PG = 58.33%, and PGNIA = 62.5%. At d 7 the OR for normoketonemia in PGNIAFM cows were 1.5 (95% CI, 1.03-2.17) and 1.4 (95% CI, 0.99-1.97) relative to PG and PGNIA, respectively. At d 3, 7, and 14, PGNIAFM cows presented the lowest values of BHB (PG = 1.36; PGNIA = 1.24; PGNIAFM = 0.89 ± 0.13 mmol/L), NEFA (PG = 0.58; PGNIA = 0.59; PGNIAFM = 0.45 ± 0.02 mmol/L), and acute phase proteins. Cows in PGNIAFM also presented the highest blood glucose increment across time points and insulin by d 7. These data provide evidence that bacteremia or endotoxemia, systemic inflammation, and pain may play a crucial role in CK pathogenesis. Additionally, targeting lipolysis and inflammation with NIA and FM during CK effectively reduces dyslipidemia biomarkers, improves glycemia, and improves overall clinical recovery.

Ex vivo evaluation of a novel suture loop method for equine intestinal biopsies.

OBJECTIVE: To compare a novel suture loop method for intestinal biopsies (SLB) with a two-layer, hand-sutured biopsy (HSB) technique in equine small and large intestines. STUDY DESIGN: Experimental, randomized, ex vivo study. ANIMALS: Eight healthy adult horses. METHODS: The duodenum, aboral jejunum, and ventral and dorsal large colon were harvested after euthanasia and divided into three sections each. The sections were randomized to SLB, HSB, or control (C, no biopsy) groups. Tissue samples were excised after placement of a suture loop formed by a 4S Roeder knot and oversewn with a Cushing pattern using barbed suture (SLB), or a simple continuous pattern oversewn with a Cushing pattern (HSB). Intraluminal diameter was assessed with contrast radiographs; bursting pressure and wall tension were determined using a solid-state sensor after instillation of fluid. Tissue samples were evaluated by a board-certified pathologist. RESULTS: Tissue samples were full thickness with similar depth and quality (p > .3). Changes in intraluminal diameter did not differ between methods (p > .16). The bursting pressures were higher for controls than biopsied sections (p < .009) but were not different between biopsy methods (p = .998). Bursting wall tension was higher for controls (p < .02) and was similar for both biopsy methods (p = .852). CONCLUSION: The SLB was equivalent to HSB in strength and effect on intraluminal diameter. The HSB samples were larger and more likely to contain mucosa/villi for histologic diagnosis. CLINICAL SIGNIFICANCE: The SLB method can be adapted for laparoscopic surgery to obtain both small and large intestinal biopsies. Further investigation is needed before clinical use.

Prevalence of Gastric Ulceration in Horses with Enterolithiasis Compared with Horses with Simple Large Intestinal Obstruction.

Enterolithiasis is a well-documented cause of colic in horses, especially in some geographic areas such as California and Florida. This retrospective case-control study aims at comparing the prevalence of gastric ulcers in horses affected by enterolithiasis to that in horses affected by other types of large intestinal obstruction. Two hundred and ninety-six horses were included in the study sample. Horses that had surgery for the removal of one or more enteroliths were included in the study as cases. Patients that had surgery for large intestinal simple obstructions other than enterolithiasis (large colon displacement, non-strangulating large colon torsion, and large and small colon impactions) were selected to match case horses for age, sex, and breed and included as controls. A total of 101/148 horses with enteroliths (68%) had gastric ulcers diagnosed during hospitalization, compared with 46/148 of matched controls (31%). There was a significant association between enterolithiasis and gastric ulceration (odds ratio 4.76, p < 0.0001), and a greater prevalence in Thoroughbreds as compared with other breeds (odds ratio 22.6, p < 0.0001). We concluded that enterolithiasis is significantly associated with gastric ulceration (p < 0.0001). The association is stronger in Thoroughbreds.

Effects of methionine, leucine, and insulin on circulating concentrations and mammary extraction of energy substrates and amino acids in lactating dairy cows.

The aim of this experiment was to test whether insulin potentiates the effects of two abomasally infused amino acids (AA), leucine and methionine (LM), on mammary extraction efficiency of energetic and nitrogenous nutrients. Six lactating Holstein cows (155 ± 9 DIM) were ruminally-cannulated and had the right carotid artery subcutaneously transposed. Cows were fed a 20% metabolizable protein-restricted diet and abomasally infused with water (8 L/d) or AA (Met 26 g/d, Leu 70 g/d) for 8 h/d, for 7 days. On the last day of each period, cows were intravenously infused with saline (0.9% NaCl, 110 mL/h) or subjected to 8 h hyperinsulinemic clamp (IC) alongside abomasal infusions. For IC, insulin was infused at 1 µg/kg/h. Normoglycemia was maintained by varying glucose (50% w/v in water) infusion rate based on coccygeal vein glucose concentration. Carotid arterial and subcutaneous abdominal (mammary) vein blood samples were collected at 0, 1, 2, 4, and 6 h from the start of infusions. Milk weights and samples for baseline measurements of production were taken on day 5 PM, day 6 AM and PM, and day 7 AM of the experimental period. A final milk weight and sample was taken immediately after abomasal and intravenous infusions on day 7 PM for assessing the interaction between insulin and the infused AA. The experiment had an incompletely replicated Latin square design with a 2 × 2 factorial arrangement of treatments (abomasal and intravenous infusion). Baseline milk production when cows were only receiving abomasal infusions was largely unaffected by LM, but milk protein yield tended to be decreased. On day 7, LM tended to positively increase milk fat and de novo fatty acid content, and IC tended to decrease milk protein content. Both milk urea nitrogen and plasma urea nitrogen were decreased by IC. Circulating AA concentrations in plasma were decreased by both LM and IC, but mammary extraction efficiency was affected by neither. Infusion of LM had no effect on any energy metabolite analyzed. Circulating non-esterified fatty acid concentration was decreased by IC, with no effect on mammary extraction efficiency. Mammary extraction efficiency of both acetate and ß-hydroxybutyrate were decreased by IC. Overall, while both circulating concentrations of energy metabolites and amino acids were decreased in response to treatments, this was not due to improved mammary extraction efficiency.

Ex vivo comparison of the bursting strength of an equine ventral midline celiotomy covered by two standard abdominal bandages.

OBJECTIVE: To determine the compressive effect of abdominal bandages after ventral midline celiotomy closure in horses. STUDY DESIGN: Ex vivo, experimental study. ANIMALS: Equine cadavers (n = 18), six per group. METHODS: A 20-cm ventral midline celiotomy was created in each of 18 equine cadavers. A 200-L inflatable bladder was placed in the abdomen, and the linea alba was apposed. Horses were randomly assigned to no bandage (C), elastic (E), or Velcro inelastic (I) bandage groups for testing. Circumferential bandages were placed with a subbandage pressure monitoring system over the incision. The bladder was insufflated until construct failure, which was determined by a decrease in pressure reading. Bursting pressure, location of body wall or bandage failure, and subbandage pressures were recorded. RESULTS: Maximum bursting pressure was different between groups E and C (P = .004), with no difference between groups E and I (P = .146) or I and C (P = .085). Group I achieved higher subbandage pressure compared with group E (P = .036). Abdominal compliance was not different between groups (P = .099). Location of failure differed between groups (P = .011), with failure at the diaphragm more common in group I (6/6, 100%) compared with groups E (3/6 [50%]) and C (1/6 [16.7%]). CONCLUSION: Elastic abdominal bandages had higher abdominal bursting pressures compared with unbandaged incisions.

Outcome of external beam radiotherapy for treatment of noncutaneous tumors of the head in horses: 32 cases (1999-2015).

BACKGROUND: The long-term outcomes of external beam radiotherapy for treatment of noncutaneous tumors of the head in horses is unknown. OBJECTIVE: To report the long-term outcomes for treatment of noncutaneous tumors of the head of horses, and report short and long-term clinical adverse effects. ANIMALS: Thirty-two horses treated in 2 referral hospitals. METHODS: In this retrospective study, medical records of horses receiving radiation therapy for noncutaneous tumors between 1999 and 2015 were reviewed. Signalment, tumor type, treatment protocol, tumor control duration, and survival were recorded. Kaplan-Meier survival curves were generated for overall survival (OS), by tumor type and location, and compared using Log-rank tests, and treatment protocol adherence. RESULTS: Follow-up ranged from 2 to 145 months (median 14 months). Of 32 horses, 16 (50%) were alive at the time of reporting, with complete tumor response occurring in 12 (38%). Horses with tumors of the maxilla/nasal cavity had significantly shorter median OS compared to horses with tumors in other locations (21 months vs 145 months) (P = .06). Adverse effects resulting from the tumor or the therapy occurred in 20/32 (63%). The occurrence of major adverse effects and delays in treatment protocol were not significantly associated with median survival estimates. CONCLUSIONS AND CLINICAL IMPORTANCE: External beam radiotherapy can be used to treat a variety of noncutaneous tumors of the head of horses. Adverse effects related to radiotherapy or the tumor are common.

Evaluation of the effects of medial saphenous venous pressures as an indirect method of measurement of intra-abdominal pressures in the horse.

OBJECTIVE: To evaluate the effect of changes in intra-abdominal pressure (IAP) on medial saphenous venous pressure (MSVP) and hemodynamics in normal horses. DESIGN: Experimental, in-vivo study. SETTING: University Teaching Hospital. ANIMALS: Convenience sample of 7 mixed breed horses; 5 geldings, and 2 mares. INTERVENTIONS: Pneumoperitoneum was induced in horses under standing sedation with carbon dioxide gas using a laparoscopic insufflator for a total of 60 minutes to simulate clinical elevation in IAP. Pressure was increased stepwise to 20 mm Hg over 30 minutes, and maintained at that pressure for 30 minutes to evaluate the effect of sustained intra-abdominal hypertension. The MSVP and vital parameters were recorded, along with direct arterial blood pressure from the transverse facial artery. MEASUREMENTS AND MAIN RESULTS: As IAP increased, MSVP increased in a stepwise manner, in concert with changes in IAP. The consistency in measurement between MSVP and IAP was high (intraclass correlation coefficient = 0.92; P < 0.001) and repeated measures correlation was excellent (r = 0.98; P < 0.001). Heart rate was unchanged over the course of the experiment (P = 0.09), however, respiratory rate increased with increasing IAP (P < 0.001). Arterial blood pressure also increased with insufflation (P < 0.001), with a significant difference at an IAP of 15 mm Hg (P = 0.04). CONCLUSIONS: This report provides preliminary data demonstrating a strong correlation between equine MSVP and changes in IAP, similar to that observed in other species. Further investigations are needed to evaluate this relationship, and to confirm these results in clinical patients.

In vitro evaluation of the modified forwarder knot used to end a continuous suture pattern in large-gauge suture.

OBJECTIVE: To evaluate the strength and size of forwarder end (FE) knots modified to end continuous suture lines compared with Aberdeen (AB), square (SQ), and surgeon's (SU) knots. STUDY DESIGN: In vitro mechanical study. STUDY POPULATION: Knotted suture. METHODS: Knots were tied with 2 USP (United States Pharmacopeia) polydioxanone, 2 USP, and 3 USP polyglactin 910 and tested on a universal testing machine under linear tension. Mode of failure and knot holding capacity (KHC) were recorded, and relative knot security (RKS) was calculated. Knot volume and weight were determined by digital micrometer and balance. Knot holding capacity, RKS, size, and weight between knot type, number of throws, and suture type and size were compared by using analysis of variance testing, with P < .05 considered significant. RESULTS: In all suture types and number of throws, FE knot KHC/RKS was 28% to 66.99% (1.2-1.6 fold) stronger compared with SQ/SU knots (P < .001). For 2 USP polydioxanone, FE knots had 10% (1.1 fold) higher KHC/RKS compared with AB knots (P < .042). However, in 2 and 3 USP polyglactin 910, FE knot KHC/RKS values were not different from those of AB knots (P > .080). Forwarder end/AB knots failed by suture breakage at the knot, whereas some SQ/SU knots unraveled. Forwarder end knots in 2 and 3 USP polyglactin 910 were 21.1% to 44.4% (1.2-1.4 fold) smaller compared with SQ/SU knots (P < .028). Forwarder end knots in 2 and 3 USP polyglactin 910 were 40% to 99% (1.4-2.0 fold) larger compared with AB knots (P < .001). CONCLUSION: Forwarder end knots provided increased KHC/RKS compared with SQ/SU knots. CLINICAL RELEVANCE: Forwarder end knots should be considered for closures when suture is placed under tension.

Evaluation of the effects of intraabdominal hypertension on equine central venous pressure.

OBJECTIVE: To evaluate the effect of changes in intraabdominal pressure (IAP) on central venous pressure (CVP) in normal horses. DESIGN: Experimental, in vivo study. SETTING: University Teaching Hospital. ANIMALS: Convenience sample of 7 mixed breed horses-5 geldings and 2 mares. INTERVENTIONS: Pneumoperitoneum was induced in horses under standing sedation with carbon dioxide gas using a laparoscopic insufflator for a total of 60 minutes to simulate clinical elevation in IAP. Pressure was increased stepwise to 20 mm Hg over 30 minutes, and maintained at that pressure for 30 minutes to evaluate the effect of sustained intraabdominal hypertension. CVP was obtained from the cranial vena cava, concurrent with pressure obtained from the peritoneal cavity. MEASUREMENTS AND MAIN RESULTS: CVP increased as IAP increased up to 12 mm Hg, and declined as IAP increased further. The changes in CVP over time were significantly different (P < 0.03). Repeated measures correlation was positive, and highest, for mean CVP as IAP increased from 0 to 12 mm Hg (r = .70; 95% CI, .43-.85; P < 0.0001). Correlation of mean CVP with insufflation pressure became negative as IAP increased further from 15 to 20 mm Hg (r = -.47; 95% CI, -.66 to -.21; P = 0.0006). CONCLUSIONS: This report provides preliminary data demonstrating a biphasic trend in equine CVP caused by changes in IAP, similar to that observed in other species. Further investigations are needed to evaluate this trend and to confirm these results in clinical patients.

Meta-analysis of the Effect of Treatment Strategies for Nephrosplenic Entrapment of the Large Colon.

A variety of treatment strategies for nephrosplenic entrapment of the large colon are reported, with conflicting evidence in the published literature as to the preferred treatment option. The aim of this study is to provide a systematic meta-analytical assessment of the efficacy of different treatment strategies in horses with confirmed or suspected nephrosplenic entrapment. This study involves meta-analysis including nonrandomized studies. A comprehensive literature search was performed from January 1970 to January 2017. Inclusion criteria were retrospective studies involving horses with confirmed and suspected nephrosplenic entrapment. A meta-analysis was performed using a random effects model, with the effect size calculated as an odds ratio (OR) with 95% confidence intervals. Statistical significance was P < .05. Out of 84 peer reviewed publications that met the search criteria, 19 relevant studies were identified. Using an OR as the effect size, the meta-analysis noted that the choice of medical or surgical therapy had no statistically significant effect on survival (P = .134). Patients treated via the rolling technique were no more likely to resolve with medical management than those treated via jogging (P = .187). Patients treated with phenylephrine were no more likely to exhibit medical resolution than patients that did not receive phenylephrine, either when all medical treatment methods were considered (P = .290), or when rolling under general anesthesia was used (P = .331). Treatment strategy, including medical versus surgical therapy, does not affect the likelihood of resolution of nephrosplenic entrapment. However, the lack of randomized trials means the results should be treated with caution and case selection remains important..

Transposition of the common carotid artery in standing cattle.

OBJECTIVE: To describe a method for permanent transposition of the common carotid artery (CCA) in standing cattle. STUDY DESIGN: Experimental study. ANIMALS: Eight healthy, adult, lactating Holstein-Friesian cows. METHODS: Cows were restrained with the head and neck extended by using halters, head catch, and squeeze chute. Surgery was performed under local anesthesia and intravenous sedation. The right CCA was approached through a skin incision dorsal and parallel to the jugular vein. The skin incision was extended through the brachiocephalicus and longus capitus muscles. When the vessel was present, ligation of accessory vessels of the CCA and internal jugular vein was performed to facilitate exposure. The artery was sharply dissected from the carotid sheath and elevated by using Penrose drains. The muscles were closed in two layers, leaving the artery in a subcutaneous position. The incision was protected with a tie-over bandage for 1 week. Sampling from the CCA was initiated approximately 6 weeks after surgery. RESULTS: The CCA was successfully transposed and used for repeated arterial blood sampling in all eight cows. No cows had intraoperative complications or evidence of surgical site infection. One cow had a postoperative suture reaction at the site of a suture used for maintaining the tie-over bandage. All arteries remained patent for use in subsequent studies. CONCLUSION: Permanent translocation of the CCA was successful in all cows in this study and consistently allowed serial arterial blood sampling. CLINICAL SIGNIFICANCE: Common carotid artery translocation is possible without general anesthesia in adult cattle and is useful in studies requiring serial sampling of arterial blood.

Meta-analysis of the effects of lidocaine on postoperative reflux in the horse.

OBJECTIVE: To determine the efficacy of lidocaine at reducing incidence of postoperative reflux (POR) in horses by using quantitative statistical analysis. STUDY DESIGN: Systematic meta-analytical review. SAMPLE POPULATION: Studies on horses undergoing gastrointestinal surgery for small intestinal lesions, identified by systematic search between 2001 and 2017. METHODS: A search with PubMed/MEDLINE, Web of Science, and Google Scholar was performed, followed by secondary searches of veterinary trade journals and bibliographies of relevant articles. The primary outcome measure for this study was the effect of lidocaine therapy on the odds of POR. Subgroup analysis assessed included the timing of lidocaine therapy, incidence of mortality, and incidence of repeat celiotomy. A meta-analysis was performed with a random effects model, with the effect size calculated as an odds ratio (OR) with 95% confidence intervals (CI). Statistical significance was set at P < .05. RESULTS: Among 1933 peer reviewed publications that met the initial search criteria, 12 relevant studies were available for analysis. Lidocaine was associated with an increased incidence of diagnosis of POR (OR 6.3, 95% CI [1.4, 27.0], P = .01). Horses treated with lidocaine were more likely to survive to discharge (OR 6.8, 95% CI [3.9, 11.7], P < .01). CONCLUSION: Lidocaine was associated with an increased survival rate in horses undergoing exploratory celiotomy for small intestinal disease according to this meta-analysis of the recent literature. CLINICAL SIGNIFICANCE: This body of published evidence provides support to administer lidocaine in horses to improve survival rather than preventing POR.

Evaluation of a Chinese herbal supplement on equine squamous gastric disease and gastric fluid pH in mares.

BACKGROUND: Wei Le San (WLS) is a Chinese herbal formula comprised of 9 herbs selected for their putative anti-inflammatory effects. OBJECTIVES: To evaluate the effects of WLS administration in horses with nonglandular gastric ulcers. ANIMALS: Ten mixed breed mares (aged 7-21 years, 401-567 kg body weight). METHODS: Experimental design was a blinded, prospective, 2-period crossover study. All horses received a placebo (25 mL dextrose-based syrup; n = 10) and the treatment (WLS, 5 g in 25 mL dextrose-based syrup; n = 10), administered twice daily. Horses underwent a 1-week, alternating feed-deprivation period to induce or worsen existing ulcers; treatment began on day 7. Gastroscopic examination was performed on d0, d6, and d35, with gastric fluid pH obtained on d6 and d35. Gastric ulcer scores assigned by 3 masked observers were averaged for each examination. RESULTS: Ulcer number scores for horses treated with WLS (median = 0; range, 0-4) was not different from the untreated controls (median = 0.5; range, 0-4; P = .81) by the end of the treatment period. Ulcer severity score for treated horses (median = 0; range, 0-1) was also unchanged compared to the control group (median = 0.5; range, 0-1; P = .85). Gastric pH was not altered by either treatment, with a median of 2.1 (range, 1.9-4.1) for the horses treated with WLS and 2.8 (range, 1.6-7.2) in the untreated controls (P = .46). CONCLUSIONS AND CLINICAL IMPORTANCE: The experimental model used to induce gastric ulceration was unable to discern a difference between the herbal supplement and the placebo in normal horses.

In vitro evaluation of the knot-holding capacity and security, weight, and volume of forwarder knots tied with size-3 polyglactin 910 suture exposed to air, balanced electrolyte solution, or equine abdominal fat.

OBJECTIVE: To evaluate the effect of exposure to a balanced electrolyte solution (BES), or equine abdominal fat on the knot-holding capacity (KHC), relative knot security (RKS), weight, and volume of forwarder knots versus surgeon's knots. SAMPLE: 315 knots tied and tested in vitro. PROCEDURES: United States Pharmacopeia size-3 polyglactin 910 suture exposed to air (dry [control]), equine abdominal fat (fat-exposed), or BES (BES-exposed) was used to tie forwarder knots with 2, 3, and 4 throws and surgeon's knots with 5, 6, 7, and 8 throws. A universal materials testing machine was used to test the tensile strength of suture and knots to failure, and the KHC, RKS, weight, and volume of knots were determined. RESULTS: Forwarder knots had significantly higher KHC and RKS and lower volume, compared with surgeons' knots. Forwarder knots tied with fat-exposed suture had greater weight, but not volume, than did forwarder knots tied with dry or BES-exposed suture with the same number of throws. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that forwarder knots were superior to surgeon's knots when configured as start knots intended for continuous lines of suture. Exposure to media did not negatively affect mechanical or physical properties of forwarder knots and may improve specific biomechanical functions, including KHC and RKS.

Evaluation of phenylephrine and exercise with or without trocarization for treatment of suspected nephrosplenic entrapment in horses.

OBJECTIVE To report the outcomes of horses with suspected nephrosplenic entrapment (NSE) of the large colon treated by IV phenylephrine administration and exercise with and without trocarization (ie, medical management). DESIGN Retrospective, observational study. ANIMALS 134 horses. PROCEDURES Electronic medical records were searched to identify horses that underwent medical management for suspected NSE at a veterinary teaching hospital between 1995 and 2014. Demographic information, physical and ultrasonographic examination findings, treatment information (including the number of times the treatment was performed and patient response), surgical findings if applicable, complications, and patient outcome were recorded. Descriptive statistics were reported. RESULTS 72 horses had suspected NSE that resolved with medical treatment; 59 of 62 horses underwent laparotomy when medical management failed, and 3 were euthanized without surgery. Twenty-five of the 59 horses had confirmed NSE that was surgically corrected, and 34 had lesions other than or in addition to NSE. All horses that had surgically corrected NSE and 18 of 34 horses that had other lesions survived to hospital discharge. The odds of resolution of NSE with medical management were greater for horses that underwent ≤ 2 (vs > 2) treatments. The treatment success rate for horses that underwent trocarization was not greater than that for horses that did not have the procedure. CONCLUSIONS AND CLINICAL RELEVANCE Suspected NSE resolved with the described medical management for most horses. However, results indicated the potential for misdiagnosis was high. Timely surgical intervention is recommended for horses that fail to respond to medical treatment.

Bursting strength of surgeon's and self-locking knots for closure of ventral midline celiotomy in horses.

OBJECTIVE: To compare the bursting strength and failure mode of ventral midline celiotomy closed with a simple continuous suture pattern with 1 of 2 knot combinations, a novel self-locking knot combination of a forwarder start with an Aberdeen end knot (F-A) and a traditional combination of a surgeon's start with a surgeon's end knot (S-S). STUDY DESIGN: Ex vivo experimental. SAMPLE POPULATION: Equine cadavers (n = 14). METHODS: A 20-cm ventral midline celiotomy was created in 14 equine cadavers. Horses were assigned to celiotomy closure with an F-A or S-S knot combination. Prior to closure, a 200-L inflatable bladder was placed in the abdomen and then insufflated until failure of the celiotomy closure. The horses' signalment, weight, breed, and age, as well as knot combination type, mode of failure, closure time, and bursting strength (mm Hg) were recorded. RESULTS: The median bursting strength was significantly greater when incisions were closed with the F-A knot combination (388 mm Hg) compared with the S-S knot combination (290 mm Hg) (P = .035). Most incisions failed along the fascia when closed with F-A combinations and at the knot when closed with S-S combinations. CONCLUSION: The bursting strength of ventral midline incisions in equine cadavers was increased by an average of 25% when closed with the self-locking F-A knot combination. CLINICAL SIGNIFICANCE: Closing ventral midline celiotomies with an F-A knot combination may provide a more secure closure than the traditional S-S knot combination. Additional in vivo investigation is required prior to recommending this closure in clinical cases.

In vitro evaluation of square and surgeon's knots in large gauge suture.

OBJECTIVE: To investigate the strength and size of surgeon's and square knots for starting and ending continuous suture lines using large gauge suture. STUDY DESIGN: In vitro mechanical study. STUDY POPULATION: Knotted suture. METHODS: Surgeon's and square knots were tested using 2 and 3 USP polyglactin 910 and 2 USP polydioxanone under linear tension on a universal testing machine. Failure mode and knot holding capacity (KHC) were recorded, and relative knot security (RKS) was calculated as a percentage of KHC. Comparisons were made between number of throws, suture size, suture type, and knot types. Knot volume and weight were assessed by a digital micrometer and balance, respectively. RESULTS: There were no significant differences in KHC (P = .295), RKS (P = .307), volume (P = .128), or weight (P = .310) between square and surgeon's knots at the start or end of suture lines with the same number of throws and suture type. A minimum of 6 throws were required for start knots and 7 throws at end knots to prevent unraveling. Knots tied with 3 polyglactin 910 were strongest (P < .001) and 2 polyglactin 910 produced knots with higher KHC and RKS than 2 polydioxanone (P < .001). CONCLUSION: No consistent differences were detected between knots types tied with the same suture material; however, number of throws affected KHC and RKS up to 6 throws in start or 7 throws in end knots. The configuration of square and surgeon's knots performed at the end of a continuous line alters their KHC, supporting the use of additional throws for knot security.

Effect of fluid media on the mechanical properties of continuous pattern-ending surgeon's, square, and Aberdeen knots in vitro.

OBJECTIVE: To investigate the knot holding capacity (KHC) of pattern-ending square, surgeon's and Aberdeen knots each tied in 4 throw combinations using large gauge suture after exposure to media commonly found in equine abdominal surgery. STUDY DESIGN: In vitro mechanical study. SAMPLE POPULATION: Knotted suture strands (n = 10/group). METHODS: Strands of 2 polydioxanone or 3 polyglactin 910 were exposed to 1 of 4 media for 15 minutes. Control suture strands remained dry. Media used included balanced electrolyte solution, 1% sodium carboxymethylcellulose, equine serum, or equine fat. Pattern-ending knots for the 3 knot configurations were loaded to failure in a linear fashion on a materials testing machine to determine KHC. RESULTS: Surgeon's knots tied using media-exposed 3 polyglactin 910 had a significantly higher KHC than the same dry knots with 5 and 6 throws. Square knots tied using media-exposed to 3 polyglactin 910 had a significantly higher KHC than the same dry knots at 5 throws. Aberdeen knots tied with either media-exposed 2 polydioxanone or 3 polyglactin 910 had a significantly higher KHC than their equivalent dry knots. Aberdeen knots had a superior KHC, while requiring less suture than both surgeon's and square knots. CONCLUSION: Media exposure either had no effect on KHC or significantly improved the KHC of all knots investigated. Based on KHC and knot volume, Aberdeen knots tied using media-exposed 3 polyglactin 910 with 3 throws and 1 turn are recommended to end a continuous suture pattern.

In Vitro Evaluation of the Aberdeen Knot for Continuous Suture Patterns with Large Gauge Suture.

OBJECTIVE: To evaluate the strength, size, and holding capacity of the Aberdeen knot compared to surgeon's and square knots using large gauge suture. STUDY DESIGN: In vitro mechanical study. STUDY POPULATION: Knotted suture. METHODS: Aberdeen, surgeon's, and square knots were tested using 2 and 3 USP polyglactin 910 and 2 USP polydioxanone under linear tension on a universal testing machine. Mode of failure and knot holding capacity (KHC) were recorded and relative knot security (RKS) was calculated as a percentage of KHC. Knot volume and weight were quantified by a digital micrometer and balance, respectively. Strength between number of throws, suture, suture size, and knot type were compared by ANOVA and post hoc testing. P≤.05 was considered significant. RESULTS: Aberdeen knots had higher KHC and RKS than surgeon's or square knots for all suture types and number of throws (P<.001). For all suture materials, none of the Aberdeen knots unraveled, but a portion of square and surgeon's knots with <7 throws did unravel (P=.101). Aberdeen knots had a smaller volume and weight than both surgeon's and square knots with equal numbers of throws (P<.001). The knot with the combined highest RKS and smallest size and weight was an Aberdeen knot with 4 throws using 3 USP polyglactin 910. CONCLUSION: The Aberdeen knots were stronger, more secure, and smaller than surgeon's and square knots for ending a continuous suture pattern. Clinically, the Aberdeen knot may be a useful alternative for completion of continuous patterns using large gauge suture, without sacrificing knot integrity.