BACKGROUND:Perianaesthetic fluid therapy can influence oxygen delivery and tissue oxygenation, yet the optimal fluid rate in horses remains undefined. OBJECTIVES:To compare two fluid strategies on peripheral tissue oxygenation (StO2) and cardiorespiratory variables in isoflurane-anaesthetised horses. STUDY DESIGN:Randomised, controlled, experimental design with two independent groups. METHODS:Sixteen euvolemic adult horses undergoing coeliotomy were anaesthetised with xylazine, ketamine, and midazolam, maintained on isoflurane with lidocaine infusion, and randomised to lactated Ringer's solution at 2.5 mL/kg/h (maintenance; MNT) or 40 mL/kg/h (high fluids; HF) for 120 min. StO2 was measured at the extensor carpi radialis muscle using near-infrared spectroscopy. Heart rate, mean arterial pressure (MAP), central venous pressure (CVP), cardiac output (CO), serum lactate, and urine output were recorded at baseline, 60, and 120 min and analysed using mixed-effects linear regression and Bland-Altman repeated-measures correlation. RESULTS:StO2 increased over time in both groups (p ≤ 0.018) and weakly correlated with MAP (ρ = 0.36, p = 0.0498) and lactate (ρ = 0.36, p = 0.05), but not with ScvO2 or PvO2 (p > 0.88). HF had significantly higher median MAP (80 vs. 76 and 79 vs. 72 mmHg), CVP (7.5 vs. 2.7 and 17.0 vs. 4.0 mmHg), serum lactate concentrations at 60 and 120 min, respectively (3.0 vs. 1.4; 2.8 vs. 1.3 mmol/L) and total urine output (0.72 vs. 0.37; mL/kg/h) than MNT (all p < 0.001). CO increased over time in MNT but not HF. No differences were detected in StO2, CO, ScvO2, or PvO2 between groups. MAIN LIMITATIONS:Small sample size and short observation window. CONCLUSIONS:High-rate fluid therapy increased MAP, CVP, and urine output not StO2 or CO, and was associated with higher serum lactate. Tissue oxygenation improved over time regardless of fluid rate, suggesting limited benefit of aggressive crystalloid administration in anaesthetised euvolemic horses.

Objectives: To compare end-to-side (ES) and side-to-side (SS) jejunocecostomy (JC) in healthy horses. Study design: Experimental study in vivo. Animals: A total of 14 healthy adult horses underwent ventral midline celiotomy, a resection, and either an ES (n = 7) or stapled SS (n = 7) JC. Methods: Surgical times and the external lengths of completed anastomoses were measured. Physical examinations and pain scoring were performed every 6 h for 5 days, then once daily until euthanasia and necropsy 28 days postoperatively. Results: The anastomosis was completed more rapidly (p < .002) with the SS JC (mean 44.21 +/- 4.91 min) than the ES JC (mean 54.24 +/- 4.59 min). One horse in the ES group developed colic from an ischemic anastomosis and was euthanized. Three horses (1 ES JC and 2 SS JC) exhibited mild colic postoperatively, and the remaining horses had no complications. Postoperative heart rates and pain scores were similar between groups (p < .16 and p < .67, respectively). The internal length of the anastomosis was significantly larger (p < .001) in the SS JC (mean 9.27 +/- 1.05 cm) than the ES JC (mean 6.31 +/- 1.4 cm) at necropsy. Conclusion: Both methods for JC were well tolerated and functional in both groups using the selected protocols for anesthesia, surgery and aftercare.

BACKGROUND:Obstruction by strangulating lipoma (SLO) is one of the most common causes of small intestinal strangulation in horses and is fatal without surgery. Current knowledge of risk factors for SLO is limited to horse signalment features. To date, other risk factors have not been investigated. OBJECTIVES:To investigate horse- and management-level risk factors for SLO using a population of healthy horses as controls. STUDY DESIGN:Matched, case-control study. METHODS:A prospective, international multicentre study was conducted in the UK and USA between January 2022 and May 2024. Cases were horses with SLO confirmed at exploratory laparotomy at the four participating hospitals. Three controls per case were randomly selected, matched on clinic and time. Conditional logistic regression was used to identify associations between variables and the risk of SLO. RESULTS:Data from 55 SLO cases (UK, n = 42; USA, n = 13) and 167 matched controls were analysed. In a final multivariable model, increased age (odds ratio [OR]: 1.15; 95% confidence intervals [95% CI]: 1.04-1.28; p = 0.008) and particular breeds (Pony, Welsh Section D/Cob, American Quarter Horse/American Paint Horse/Appaloosa/Arabian) were at increased risk of SLO (OR: 1.53; 95% CI: 1.10-2.15; p = 0.012). SLO was more likely in horses with a prior history of laminitis (OR: 10.94; 95% CI: 2.21-54.13; p = 0.003) or increased stabling in the previous 4 weeks (OR: 6.79; 95% CI: 1.96-23.54; p = 0.003). Management strategies to maintain optimal weight and address equine metabolic syndrome were protective (OR: 0.19, 95% CI: 0.39-0.94; p = 0.041). MAIN LIMITATIONS:Potential for selection and recall bias by horse owners. CONCLUSIONS:This study adds to knowledge of the epidemiology of SLO and has identified new risk factors which may be modifiable. Strategies to prevent endocrine-associated laminitis, including weight management in high-risk groups, should be considered to minimise SLO risk.

BackgroundJejunocaecostomy (JC) is frequently required to bypass diseased ileum as a side-to-side (SS) anastomosis with blind end closure of the small intestine. The effects of the blind end closure method on the performance of the anastomosis have not been studied. ObjectivesTo compare handsewn and stapled blind end closures of the ileum and jejunum. Study designIn vivo experiments. MethodsJC was performed with either Parker-Kerr (PK; 6 horses) or oversewn stapled technique (OS; 6 horses) to close jejunum and ileum for an SS anastomosis. At surgery, peritoneal fluid was analysed and various anastomotic measurements and time to complete the anastomosis were recorded. Physical and haematological findings and serum amyloid A (SAA) were recorded postoperatively. At necropsy on day 7, anastomotic measurements and peritoneal fluid analysis were repeated. Tissues collected at surgery and necropsy underwent histological and immunohistological evaluations. ResultsTwo PK horses developed intussusception of the jejunal blind end into the caecum and another PK horse was euthanised because of anastomotic impaction. One OS horse had mild postoperative colic. Postoperative peripheral neutrophil counts and SAA were similar between groups but SAA significantly (0.5 mg/L [0.3, 0.7], p < 0.001) increased with time in both. The OS jejunal blind ends (4.7 cm [4.41, 6.85]) were significantly larger (PK = 3.5 cm [3.3, 4.08], p = 0.004) and the OS blind ends (18.6 min +/- 1.32) were significantly slower to complete (11.3 min +/- 0.37, p = 0.002). Inflammation developed between the everting staple line and inverting suture line in the OS closure and along transected edges in the PK. Peritoneal fluid total protein increased significantly between surgery (19 g/L [19, 19]) and necropsy (34 g/L [30, 41], p < 0.001) without differences between groups. Main limitationsSmall sample size and short follow-up. ConclusionBoth blind-end techniques could be acceptable, although more complications developed with the PK method. The anastomotic intussusceptions were unexpected and possibly unique to the anastomotic design.

BACKGROUND:Strangulating lipoma obstruction (SLO) is the most common cause of equine small intestinal strangulation and is fatal without surgery. Currently, epidemiological information is primarily limited to signalment-related risk factors and requires further investigation. OBJECTIVES:To identify horse-level risk factors for SLO and/or abdominal lipoma(s) (LP) formation in horses with acute colic that underwent surgery or post-mortem examination at participating equine clinics. STUDY DESIGN:Prospective, international, multicentre, epidemiological study. METHODS:An epidemiological study was conducted over 27 months (January 2022-April 2024) in 8 clinics (UK n = 4, USA n = 4) to identify variables associated with altered likelihood of SLO and/or LP. Horses presenting with acute colic signs that underwent surgery or post-mortem examination were eligible. Those (i) that had SLO as the primary cause of colic, or (ii) those that had mesenteric and/or omental lipoma(ta) (LP) were compared to horses without lipomata. Signalment, adiposity, endocrine status, and lipomata deposition data were analysed using univariable and multivariable logistic regression models. RESULTS:Data from 392 horses was obtained (108 SLO; 190 LP). Increasing age (odds ratio [OR] 1.23) for every year increase in age 95% CI (95% CI: 1.17-1.30, p < 0.001), male sex (OR 1.78, 95% CI: 1.08-2.95, p = 0.02) and clinical indicators of Equine Metabolic Syndrome (EMS) (OR 4.77, 95% CI: 2.93-7.77, p < 0.001) were significantly associated with increased likelihood of SLO. Increasing age, clinical indicators of EMS, indicators of previous/current laminitis (hoof growth ring score), jejunal mesenteric fat score and omental fat scores were significantly associated with increased likelihood of LP. MAIN LIMITATIONS:Population restricted to horses with acute colic signs admitted to collaborating clinics. CONCLUSIONS:Measures to prevent adiposity and EMS development appear important to reduce the likelihood of LP and SLO. Further investigation of differential adipose tissue deposition between male and female horses is warranted.

Objective:To determine if blood and peritoneal fluid levels of syndecan-1, heparan sulfate, and hyaluronan are elevated in horses with small intestinal disease compared to healthy counterparts. Methods:61 horses were categorized into control (n = 20), inflammatory (11), and strangulating (30) groups. Paired peritoneal fluid and blood samples were obtained from each group from December 2016 through December 2024 and analyzed via equine-validated ELISAs for syndecan-1, heparan sulfate, and hyaluronan concentrations. Patient survival to discharge was recorded for all groups. Immunofluorescence staining was performed on sections of healthy and diseased jejunum. Results:Syndecan-1 concentrations were higher in horses with disease (inflammatory and strangulating lesions) compared to controls, in inflammatory peritoneal fluid relative to controls, and in horses that did not survive to discharge. Heparan sulfate concentrations were higher in diseased horses versus controls, in strangulating lesions compared to controls, and in horses that did not survive to discharge. Hyaluronan concentrations were higher in disease compared to control, lower in the peritoneal fluid of strangulating lesions, elevated in plasma from strangulating lesions, and higher in horses that did not survive to discharge. Immunofluorescence revealed a greater number of heparan sulfate-positive cells in diseased intestinal tissue. Conclusions:These findings suggest that endothelial glycocalyx degradation is associated with small intestinal disease and nonsurvival to discharge in equine small intestinal colic. Clinical Relevance:Further investigation is needed to determine if measurement of endothelial glycocalyx biomarkers may offer a novel approach for assessing intestinal injury and guiding clinical decision-making in horses with gastrointestinal disease.

OBJECTIVE:To develop a modified stapled (MS) jejunocecostomy (JC) in healthy horses. STUDY DESIGN:In vivo experimental study. ANIMALS:Six healthy adult horses underwent ventral midline celiotomy, a jejunal resection, and an MS. METHODS:Time to complete anastomosis and anastomotic length at necropsy were recorded. Horses were assessed by physical examination every 6 h for 5 days after surgery, then once daily until euthanasia at 7 days. A group of seven horses that had a stapled side-to-side JC and were euthanized 28 days postoperatively was used as an historical control (SS). RESULTS:All MS horses recovered well, although one developed transient mild colic and another had a brief period of pyrexia and diarrhea. Postoperative heart rates returned to preoperative values shortly after surgery. At necropsy, the MS anastomoses appeared grossly to be healing well and formed a wide triangulated stoma. Times to complete the anastomosis (p = .49) and lumen size at necropsy (p = .32) were similar for both groups. CONCLUSION:The MS method was performed with ease and appeared to function effectively. It produced a triangulated stoma that could facilitate flow and reduce the risk of impaction. CLINICAL SIGNIFICANCE:This study supports the use of MS for JC in horses. Although the study size was small, the results compared favorably with historical data for a SS for JC in healthy horses. The elimination of oversewn ends simplifies the MS technique and allows a single application of the stapler, minimizing cost.

Background: The need for capsular closure during arthroscopic hip labral repair is debated. Purpose: To compare pain and functional outcomes in patients undergoing arthroscopic hip labral repair with concomitant repair or plication of the capsule versus no closure. Study Design: Cohort study. Methods: Outcomes were compared between patients undergoing arthroscopic hip labral repair with concomitant repair or plication of the capsule versus no closure at up to 2 years postoperatively and with stratification by age and sex. Patients with lateral center-edge angle <20°, a history of instability, a history of prior arthroscopic surgery in the ipsilateral hip, or a history of labral debridement only were excluded. Subanalysis was performed between patients undergoing no capsular closure who were propensity score matched 1:1 with patients undergoing repair or plication based on age, sex, and preoperative Modified Harris Hip Score (MHHS). We compared patients who underwent T-capsulotomy with concomitant capsular closure matched 1:5 with patients who underwent an interportal capsulotomy with concomitant capsular repair based on age, sex, and preoperative MHHS. Results: Patients undergoing capsular closure (n = 1069), compared with the no-closure group (n = 230), were more often female (68.6% vs 53.0%, respectively; P < .001), were younger (36.4 ± 13.3 vs 47.9 ± 14.7 years; P < .001), and had superior MHHS scores at 2 years postoperatively (85.8 ± 14.5 vs 81.8 ± 18.4, respectively; P = .020). In the matched analysis, no difference was found in outcome measures between patients in the capsular closure group (n = 215) and the no-closure group (n = 215) at any follow-up timepoint. No significant difference was seen between the 2 closure techniques at any follow-up timepoint. Patients with closure of the capsule achieved the minimal clinically important difference (MCID) and the patient acceptable symptom state (PASS) for the 1-year MHHS at a similar rate as those without closure (MCID, 50.3% vs 44.9%, P = .288; PASS, 56.8% vs 51.1%, P = .287, respectively). Patients with T-capsulotomy achieved the MCID and the PASS for the 1-year MHHS at a similar rate compared with those with interportal capsulotomy (MCID, 50.1% vs 44.9%, P = .531; PASS, 65.7% vs 61.2%, P = .518, respectively). Conclusion: When sex, age, and preoperative MHHS were controlled, capsular closure and no capsular closure after arthroscopic hip labral repair were associated with similar pain and functional outcomes for patients up to 2 years postoperatively.

The purpose of this study was to compare PROMs in patients undergoing anterior glenoid labral repair using all-suture versus conventional anchors. We hypothesized PROMs would be similar between groups. We performed a retrospective review of the Arthrex Global Surgical Outcomes System (SOS) database, querying patients who underwent arthroscopic glenoid labral repair between 01/01/2015 and 12/31/2020. Patients aged 18–100, who had isolated glenoid labrum repair with at least 12-month follow-up were included. The visual analog pain scale (VAS), Western Ontario Shoulder Instability Index, Veteran’s RAND 12-items health survey, single assessment numeric evaluation and the American Shoulder and Elbow Surgeons score (ASES) were compared preoperatively, 3 months, 6 months, 1 year and 2 years postoperatively in patients who received all-suture anchors versus conventional anchors in the setting of anterior glenoid labrum repair. Our primary aim was comparison of PROMs between patients receiving all-suture versus conventional suture anchors. Secondarily, a sub-analysis was performed comparing outcomes based on anchor utilization for patients with noted anterior instability. We evaluated 566 patients, 54 patients receiving all-suture anchors and 512 patients receiving conventional anchors. At two-year follow-up there was no significant difference between the two groups in PROMs. In a sub-analysis of isolated anterior labrum repair, there was an improvement in ASES (P = 0.034) and VAS (P = 0.039) with the all-suture anchor at two-year follow-up. All-suture anchors provide similar or superior pain and functional outcome scores up to 2 years postoperatively compared to conventional anchors. As all-suture anchors gain popularity among surgeons, this is the largest scale study to date validating their use in the setting of glenoid labrum repair. Institutional Review Board (IRB): IRB202102550.

Background Restoration of external (ER) and internal rotation (IR) after Grammont-style reverse shoulder arthroplasty (RSA) is often unreliable. The purpose of this systematic review was to evaluate the influence of RSA medio-lateral offset and subscapularis repair on axial rotation after RSA. Methods We conducted a systematic review of studies evaluating axial rotation (ER, IR, or both) after RSA with a defined implant design. Medio-lateral implant classification was adopted from Werthel et al. Meta-analysis was conducted using a random-effects model. Results Thirty-two studies reporting 2,233 RSAs were included (mean patient age, 72.5 years; follow-up, 43 months; 64% female). The subscapularis was repaired in 91% (n=2,032) of shoulders and did not differ based on global implant lateralization (91% for both, P=0.602). On meta-analysis, globally lateralized implants achieved greater postoperative ER (40° [36°–44°] vs. 27° [22°–32°], P<0.001) and postoperative improvement in ER (20° [15°–26°] vs. 10° [5°–15°], P<0.001). Lateralized implants with subscapularis repair or medialized implants without subscapularis repair had significantly greater postoperative ER and postoperative improvement in ER compared to globally medialized implants with subscapularis repair (P<0.001 for both). Mean postoperative IR was reported in 56% (n=18) of studies and achieved the minimum necessary IR in 51% of lateralized (n=325, 5 cohorts) versus 36% (n=177, 5 cohorts) of medialized implants. Conclusions Lateralized RSA produces superior axial rotation compared to medialized RSA. Lateralized RSA with subscapularis repair and medialized RSA without subscapularis repair provide greater axial rotation compared to medialized RSA with subscapularis repair. Level of evidence 2A.

OBJECTIVE Right dorsal colitis causes chronic colic associated with long-term treatment with nonsteroidal antiinflammatory drugs (NSAIDs). This study was designed to determine if NSAIDs could inhibit anion transporters that protect against intestinal mucosal injury in other species. ANIMALS 20 healthy horses. METHODS The effects of indomethacin (INDO) and firocoxib (FIR), on short-circuit current (Isc) in mucosa from the right dorsal colon (RDC) and right ventral colon (RVC) were measured in Ussing chambers by standard electrophysiological techniques. Immunohistochemical methods were used to detect apoptosis (caspase-3) with these NSAIDs and phenylbutazone (PBZ) and to locate the NKCC1 transporter. RESULTS The Isc in RDC and RVC incubated with INDO or FIR was increased almost 3-fold ( P < .0001) by prostaglandin E 2 (PGE 2 ) through a system inhibited by loop diuretics ( P < .0001). Although these findings and anion replacement studies were consistent with anion secretion, the RDC also displayed an Isc response suggestive of a unique transporter apparently absent in RVC or NSAID-free solutions. In RDC, FIR, INDO, and PBZ induced apoptosis in the lower half of crypts. However, significant differences in apoptotic index were recorded in the RDC between NSAID-treated and control tissues (no NSAID). CLINICAL RELEVANCE The effects of NSAIDs on Isc were consistent with reduced anion secretion, which could represent the pharmacological equivalent of the transport failure responsible for Cystic Fibrosis (CF) in other species. Failure of anion secretion could interfere with buffering acid from intraluminal fermentation, which could suggest a treatment target for right dorsal colitis.

Objective: To compare single-layer anastomoses (modified continuous Lembert [mod-CL] and modified-interrupted Lembert [mod-IL]) and a 2-layer simple continuous anastomosis (2 L; seromuscular and mucosal) for jejunojejunal anastomoses in equine cadavers and to compare ex vivo to in vivo time to complete the anastomosis and stoma size with a mod-IL pattern. Study design: Measurements in jejunum from cadaver and anesthetized horses. Animals: Ten live horses and 18 equine cadavers. Methods: Time to complete anastomosis, bursting pressures (BP), leakage sites, and anastomotic index (size ratio of anastomotic lumen to control lumen) were recorded. Time to completion and lumen size were compared between in vivo and ex vivo mod-IL patterns. Results: The mod-CL pattern was fastest (8.44 +/- 1.30 min, p < .05), and the 2 L pattern was slower (17.07 +/- 2.0 min) than the mod-CL and mod-IL (p < .05). The anastomotic index exceeded 100 and did not differ between patterns. Segments reached higher bursting pressures when anastomosed with mod-IL (145.94 +/- 24.18 mm Hg) than mod-CL (p < .05). In vivo closure was approximately 8 minutes slower than ex vivo, and with a smaller anastomotic index. Conclusions: All anastomoses increased lumen size over control segments. Lumen size after placement of a mod-IL was greater ex vivo than in vivo, and completion was slower in vivo than ex vivo. Clinical significance: Slower and smaller anastomoses should be anticipated in vivo compared to ex vivo results. Anastomoses with a mod-IL pattern appear clinically advantageous, producing a comparable lumen size in less time than 2 L.

Repeat celiotomy can be lifesaving in horses with a surgically treatable postoperative obstruction, although guidelines for its use are lacking, except for uncontrollable postoperative pain. Overdiagnosis of ileus as the cause of postoperative obstruction could delay a second surgery so the disease progresses beyond a manageable level of severity. Although many horses respond favorably to repeat celiotomy, complications can be severe and life threatening, such as incisional infection and adhesions. Repeat celiotomy does not seem to exacerbate postoperative ileus, despite additional surgical manipulation. An important benefit of repeat celiotomy is termination of hopeless cases, thereby reducing cost and suffering.

OBJECTIVE:To develop 3D models of larynges to compare arytenoid abduction measurements between specimens and models, and to investigate the anatomic feasibility of placing an implant across the cricoarytenoid joint (CAJ) with or without arthrotomy.SAMPLES:Cadaveric equine larynges (n = 9).PROCEDURES:Equine larynges underwent sequential CT scans in a neutral position and with 2 arytenoid treatments: bilateral arytenoid abduction (ABD) and bilateral arytenoid abduction after left cricoarytenoid joint arthrotomy (ARTH). Soft tissue, cartilage, and luminal volume 3-dimensional models were generated. Rima glottidis cross-sectional area (CSA) and left-to-right quotient (LRQ) angles were measured on laryngeal specimens and models. Arytenoid translation, articular contact area, and length of modeled implants placed across the CAJ were measured on models. Data were analyzed using paired t test or ANOVA and Tukey's post hoc test or non-parametric equivalents (P < .05).RESULTS:ARTH CSA was larger for laryngeal specimens than models (P = .0096). There was no difference in all other measures of CSA and LRQ angle between treatment groups or between specimens and models. There was no difference between ABD and ARTH groups for arytenoid cartilage translation, contact area, and implant length. The articular contact area was sufficient for modeled implant placement across the CAJ with a narrow range of implant lengths (17.59 mm to 23.87 mm) across larynges with or without arthrotomy.CLINICAL RELEVANCE:These results support further investigation of a CT-guided, minimally invasive surgical procedure. Future studies will evaluate the outcomes of the new procedure for technical precision, biomechanical stability, and post-operative success rates for horses with recurrent laryngeal neuropathy (RLN).

BACKGROUND:Although survival rates have been reported after small intestinal surgery for strangulating diseases in horses, none have followed survival for periods relevant to the long lifespan of horses and none have described effect of age, disease and surgical treatments over such long survival periods. OBJECTIVES:To examine effects of age, disease and type of surgery on long-term survival in horses after surgical treatment of small intestinal strangulating diseases over periods relevant to the expected lifespan of a horse. STUDY DESIGN:Retrospective clinical study. METHODS:Post-operative data were gathered from medical records and owner contact for 89 horses with small intestinal strangulation. Survival times from surgery to the date of death or the date of last follow-up were analysed by Kaplan-Meier statistics. Variables of interest were age, type of strangulating disease and surgical correction. Cox proportional hazards regression was used to evaluate these variables. RESULTS:Short-term survival was not affected by any of the variables measured. For long-term survival with Kaplan-Meier statistics, horses ≥16 years old had significantly shorter (P = .002) median survival times (72 months; 95% CI 32.0-96.0) than younger horses (121.7 months; 95% CI 90.0-162), horses without resection had significantly longer (P = .02) survival times (120 months; 95% CI 86-212) than horses that had jejunocecostomy (76.8 months; 95% CI 24-125), and horses with miscellaneous diseases had significantly longer (P = .02) median survival times (161.9 months; 95% CI 72.0-M) than horses with strangulating lipoma (79.8 months; 95% CI 32.0-120.0). In the multivariable Cox Proportional Hazard model, age (HR = 2.67; 1.49-4.75, P < .001) and anastomosis (HR = 0.65; 0.46-0.92, P = .02) had the most significant effect on median survival time. MAIN LIMITATIONS:Limitations were small numbers in some categories, loss of cases to follow-up, owner recall failures and lack of a control group. CONCLUSIONS:The remaining lifespan of older horses at the time of surgery had the greatest effect on survival. Age could influence long-term survival studies after colic surgery, and therefore needs to be considered for survival analyses. Horses that did not require resection and anastomosis had favourable outcomes, underscoring the potential importance of early intervention to reduce the need for resection.

Summary The current hypothesis proposed for strangulation of small intestine by a pedunculated lipoma in horses involves movement of the lipoma around the small intestine until it loops through its own pedicle. This mechanism is difficult to demonstrate during surgical correction. The objective was to examine an alternative explanation for strangulation by pedunculated lipomas that is logical and consistent with intraoperative findings by the analysis of the anatomical features of 11 cases of lipoma strangulation in horses. In the proposed hypothesis, the stalk of the lipoma is tensed by the weight of the lipoma alone or by external forces on it from adjacent intestine. This produces a slit‐like aperture formed by the stalk and the contiguous mesentery. One or more loops of intestine pass across the lateral edge of the stalk before turning into this aperture, either because of lack of space in the abdominal cavity or through the effects of peristalsis. The weight of the intestine itself causes the loop to ‘fall’ into the aperture and become entrapped. This creates a half‐hitch knot in which the loop of intestine uses the lipoma pedicle as a ‘post’ around which it becomes strangulated. It was concluded that the proposed hypothesis differs from the existing one by requiring intestinal movement to create the strangulation, which is more plausible than the current proposal that the strangulation is caused by movement of the lipoma itself. It is also more consistent with surgical findings.

OBJECTIVE:To assess the safety and efficacy of a method for digitally enlarging the caudal aspect of the epiploic foramen (EF).STUDY DESIGN:Healthy horses and clinical cases of EF entrapment (EFE).ANIMALS:Fourteen healthy horses and three clinical cases.METHODS:Through a ventral midline celiotomy under general anesthesia, the EF was enlarged by digital separation of the caudal attachments of the caudate lobe of the liver from right dorsal colon, right kidney, gastropancreatic fold, and pancreas. Healthy horses were euthanized under anesthesia, and the enlarged EF was measured at necropsy.RESULTS:The method used for enlarging the EF did not cause clinically relevant hemorrhage, as determined by visual inspection of the EF in 14 horses at necropsy and by vital parameters under anesthesia in all horses. In clinical cases, EFE was reduced following enlargement of the EF, and no intraoperative complications were encountered. In one clinical case, necropsy at 30 days confirmed partial closure of the enlarged EF.CONCLUSION:The method proposed enlarged the EF safely and effectively. Limitations of the study include the small number of clinical cases and the lack of postoperative follow-up on the healthy horses.CLINICAL SIGNIFICANCE:Enlargement of the EF at its caudal extent should be considered in selected cases of EFE in which manual reduction is difficult or protracted. Although the procedure was safe in this study, knowledge of the anatomy, practice on cadavers, and careful selection of cases with greatest need are recommended before clinical use.

OBJECTIVE To examine bicarbonate (HCO3-) secretion ex vivo in the equine large colon to determine any differences between the right dorsal colon (RDC) and right ventral colon (RVC). The effect of phenylbutazone (PBZ) on HCO3- secretion was examined in the RDC. ANIMALS 14 healthy horses. PROCEDURES In anesthetized horses (n = 10), segments of mucosa from RDC and RVC were harvested to measure HCO3- secretion ex vivo with the pH Stat method. The effect of PBZ on HCO3- secretion in the RDC was studied in 4 additional horses. RESULTS Three distinct mechanisms of HCO3- secretion previously described in a murine model were confirmed in the equine colon. The RDC had a greater capacity for electrogenic, Cl--independent HCO3- secretion than the RVC (P = 0.04). In the RDC, all HCO3- secretion was decreased by PBZ (P < 0.02) but was not studied in the RVC because of low baseline secretion. CLINICAL RELEVANCE Secretion of HCO3- by the RDC could play a pivotal role in equine colon physiology, because intense microbial fermentation in this site could require HCO3- secretion to buffer short-chain fatty acids. Inhibition of this secretion by PBZ could interfere with mucosal buffering and predispose to changes associated with right dorsal colitis.