David E. Freeman

Surgery of the Small Intestine

Although earlier reports describe a poor prognosis for small intestinal surgery in the horse, there is growing evidence that the short-term survival rate can exceed 80%. In addition to advancements in surgery and aftercare, early referral contributes considerably to the improved prognosis. Surgical procedures that restore anatomic and physiologic continuity to close to normal can minimize postoperative complications. Jejunojejunostomy carries a better prognosis than jejunocecostomy, probably because the latter involves anastomosis between two intestinal segments with dissimilar functions. Careful technique can reduce the prevalence of complications, such as postoperative ileus and serosal adhesions.

Epidemiologic analysis of nosocomial Salmonella infections in hospitalized horses

OBJECTIVE To examine the relationship between abdominal surgery and nosocomial Salmonella infections and the relationship between high caseload in combination with abdominal surgery and nosocomial Salmonella infections in hospitalized horses with signs of gastrointestinal tract disease. ANIMALS 140 horses. DESIGN Case-control study. PROCEDURES To accomplish the first objective, 1 to 4 control horses were matched with each nosocomial case horse on the basis of admission date of a primary case horse. The frequency of abdominal surgery and other investigated exposure factors were compared between nosocomial case horses and control horses. For the second objective, 4 control horses were matched with each nosocomial case horse on the basis of year of admission. The frequency of high caseload (>or=26 inpatients), abdominal surgery, and other factors was compared between nosocomial case horses and control horses. RESULTS The odds of nosocomial Salmonella infection were 8 times as high (odds ratio=8.2; 95% confidence interval=1.11, 60.24) in horses that underwent abdominal surgery, compared with the odds for horses that did not undergo surgery. High caseload alone or in combination with abdominal surgery was not associated with increased risk of nosocomial Salmonella infection. CONCLUSIONS AND CLINICAL RELEVANCE Abdominal surgery was identified as a risk factor for nosocomial Salmonella infections in horses. Horses that undergo abdominal surgery require enhanced infection control and preventative care. Risk of nosocomial Salmonella infections may be reduced by implementation of biosecurity measures (such as the use of plastic boots, gloves, and footbaths) immediately after surgery.

Short-term survival after surgery for epiploic foramen entrapment compared with other strangulating diseases of the small intestine in horses.

REASONS FOR PERFORMING STUDY Epiploic foramen entrapment (EFE) is one of the more common causes of colic in horses, but recent reports suggest a poor prognosis after surgical treatment. HYPOTHESIS That EFE has a good prognosis compared with other small intestinal strangulating lesions. METHODS Surgical findings, surgical procedures and short-term outcome were recorded for 157 horses that underwent surgery for strangulating lesions of the small intestine at the University of Illinois from 1994 to 2003. Horses were assigned to 3 groups for comparison; those with EFE, strangulation by lipoma and miscellaneous strangulating lesions. A logistic regression model and Monte Carlo tests of the binomial proportions were used to examine survival rates. The Kruskal-Wallis test was used to determine differences in usage of surgical treatments. Measurements of length and viability indices were analysed using a one-way analysis of variance followed by Tukeys HSD test, and viability scores were analysed using an exact Kruskal-Wallis test. Significance was set at P < 0.05. RESULTS Horses with EFE were significantly more likely to be discharged (95%) than those with the other conditions (P < 0.05). The proportion of horses with ileal involvement was greater in horses with EFE than in the other 2 groups (P < 0.05), although this did not affect outcome. The distributions of viability grades for EFE and lipoma differed significantly (P < 0.05). CONCLUSIONS The prognosis for horses that had surgery at this hospital for EFE was better than for those with the other conditions, although the greater proportion of horses with EFE with ileal involvement could influence outcome. Therefore, surgeons must consider ways of improving jejunocaecostomy and determining when bowel is viable, the latter to avoid jejunocaecostomy.

Effects of flunixin meglumine on recovery of colonic mucosa from ischemia in horses.

OBJECTIVE To examine the effects of flunixin meglumine (FM) on recovery of colonic mucosa from experimentally induced ischemia in horses. ANIMALS 14 research horses. PROCEDURES Ischemia was induced in the colons of anesthetized horses for 2 hours. Afterward, horses received saline (0.9% NaCl) solution (12 mL, IV, q 12 h; n = 7) or FM (1.1 mg/kg, IV, q 12 h; 7) and were allowed to recover for 18 hours after termination of the ischemic event. Postoperative pain scores were recorded every 4 hours throughout the recovery period. At the end of the recovery period, horses were anesthetized, and ischemic and nonischemic segments of colonic mucosa were harvested for histologic evaluation, western blot analysis, and in vitro assessment of transepithelial electric resistance (TER) and transmucosal flux of tritium-labeled (3H-) mannitol. Horses were then euthanatized. RESULTS Flunixin meglumine significantly lowered pain scores at the first postoperative recording. There were no significant differences between treatment with saline solution and FM in any of the measurements for TER, 3H-mannitol flux, histomorphometric variables, neutrophil infiltration (detected via calprotectin immunostaining), and expressions of cyclooxygenase-1 and -2. After both treatments, TER declined significantly in nonischemic tissues in vitro, whereas it increased significantly in ischemic-injured tissues. CONCLUSIONS AND CLINICAL RELEVANCE Flunixin meglumine did not affect recovery of equine colonic mucosa from ischemic injury, and continued use in horses with colonic ischemia is therefore justified.

Diseases and Surgery of the Large Colon

Displacements and intraluminal obstructions of the large colon carry a good to excellent prognosis for long-term recovery, and surgery for these diseases is rarely followed by short-term or long-term complications. Entrapment of the large colon over the renosplenic ligament is amenable to medical therapies so that surgery can be avoided in many cases. However, preoperative diagnosis of all nonstrangulating diseases of the large colon can be difficult. Vascular diseases of the large colon, such as thromboembolic diseases and large colon volvulus, are more difficult to treat and carry a poorer prognosis for survival.

Comparison of complications and long-term survival rates following hand-sewn versus stapled side-to-side jejunocecostomy in horses with colic

OBJECTIVE To evaluate survival rate and complications after jejunocecostomy in horses with colic and to compare outcomes after hand-sewn versus stapled side-to-side jejunocecostomy. DESIGN Retrospective cohort study. ANIMALS 32 horses. PROCEDURES Information was retrieved from medical records and through telephone calls on horses that had a hand-sewn or stapled side-to-side jejunocecostomy for treatment of colic, which was performed by or under the supervision of the same surgeon. Kaplan-Meier life table analysis was used to compare survival times and rates between horses that underwent a hand-sewn or stapled side-to-side anastomosis. RESULTS 32 horses met inclusion criteria; 22 underwent a hand-sewn anastomosis, and 10 underwent a stapled anastomosis. Horses in the stapled group had a significantly greater prevalence of postoperative colic and combined postoperative colic and reflux than horses in the hand-sewn group. In the hand-sewn group, repeated celiotomy was performed within the same hospitalization period for 3 of 22 horses; in the stapled group, 4 of 10 horses had repeated celiotomies. Hospital discharge rates (ie, short-term survival rates) were similar between horses in the hand-sewn group (20/22 horses) and those in the stapled group (9/10 horses). Long-term survival rates were similar for both groups, ranging from 5 to 126 months. CONCLUSIONS AND CLINICAL RELEVANCE Short- and long-term results justify use of jejunocecostomy in horses. Despite similar survival rates between groups, horses that underwent a stapled anastomosis had significantly greater prevalences of postoperative complications than horses that underwent a hand-sewn anastomosis, suggesting that horses were sensitive to minor differences in anastomosis techniques.

Total and partial ovariohysterectomy in seven mares

REASONS FOR PERFORMING STUDY Ovariohysterectomy appears to have a low mortality rate in mares, but the procedure needs to be reviewed because of the high risk of life-threatening complications. HYPOTHESIS That ovariohysterectomy can be effective treatment for a variety of uterine diseases in mares and carries a good prognosis. METHODS Diagnosis, clinical data, surgical technique, post operative care, complications and outcome were recorded from medical records of 7 mares that underwent total (6) and partial (1) ovariohysterectomy at the University of Illinois from 1994 to 2001. RESULTS The indications for ovariohysterectomy were chronic pyometra (4 mares), chronic uterine torsion (n = 2) and chronic intramural haematoma (n = 1). Surgical exposure was difficult but was improved by traction on stay sutures and right-angled clamps. In some cases, application of the TA-90 autosuture instrument as a right-angled clamp to the caudal part of the uterus improved access to the uterine stump. The most common post operative complications were decreased faecal output, decreased intestinal sounds (4 mares) and mild abdominal pain (2). Two mares had mild to moderate incisional infections. Other previously reported complications, such as haemorrhage, septic peritonitis, uterine stump infection or necrosis, and diarrhoea, did not occur. All mares survived over follow-up periods of 6 months to 5 years and were used for riding (6 mares) and embryo transfer (1 mare, after partial ovariohysterectomy). CONCLUSIONS AND POTENTIAL RELEVANCE According to this study, the prognosis for mares after ovariohysterectomy appears to be good, despite the technical difficulties of the procedure. The prevalence of life-threatening complications can be lower than reported.

Management of Rectal Tears

Rectal tears have important medicolegal implications, and severe tears have a poor prognosis. Prompt diagnosis, immediate application of first aid measures, early referral, use of appropriate definitive treatments, and aggressive aftercare will improve the prognosis. The grade of rectal injury will determine the definitive treatment, but there are few guidelines to determine which treatment is best in each case. Bypass procedures, such as colostomy and indwelling rectal liner, have their own advantages and disadvantages, but can facilitate healing and prevent life-threatening complications if they are used with minimum delay. Suture of the tear can be difficult, but should be attempted to hasten healing and to prevent progression of the tear to a more severe injury.

Expression of cyclooxygenase-1 and -2 in the left dorsal colon after different durations of ischemia and reperfusion in horses.

OBJECTIVE-To identify expression and localization of cyclooxygenase (COX)-1 and COX-2 in healthy and ischemic-injured left dorsal colon of horses. SAMPLE POPULATION-Left dorsal colon tissue samples from 40 horses. PROCEDURES-Tissue samples that were used in several related studies on ischemia and reperfusion were evaluated. Samples were collected during anesthesia, before induction of ischemia, and following 1 hour of ischemia, 1 hour of ischemia and 30 minutes of reperfusion, 2 hours of ischemia, 2 hours of ischemia and 30 minutes of reperfusion, and 2 hours of ischemia and 18 hours of reperfusion. Histomorphometric analyses were performed to characterize morphological injury. Immunohistochemical analyses were performed to characterize expression and localization of COX-1 and COX-2. RESULTS-COX-1 and COX-2 were expressed in control tissues before ischemia was induced, predominantly in cells in the lamina propria. Ischemic injury significantly increased expression of COX-2 in epithelial cells on the colonic surface and in crypts. A similar significant increase of COX-1 expression was seen in the epithelial cells. CONCLUSIONS AND CLINICAL RELEVANCE-On the basis of information on the role of COX-2, upregulation of COX-2 in surface epithelium and crypt cells following ischemic injury in equine colon may represent an early step in the repair process.

Liver lobe torsion in six horses

CASE DESCRIPTION 6 horses were determined to have torsion of a liver lobe at 4 referral institutions over a 21-year period. CLINICAL FINDINGS Clinical findings were nonspecific but often included signs of marked inflammation. Two of the 6 horses were examined because of colic, and 2 were assessed because of peritonitis that failed to respond to treatment; the remaining 2 horses were examined because of nonspecific clinical signs that included inappetence, lethargy, and weight loss. The results of laboratory tests were widely variable, and values for liver enzyme activities were typically within reference limits or only mildly increased. Most affected horses had markedly increased peritoneal nucleated cell counts. TREATMENT AND OUTCOME Exploratory laparotomy and resection of the affected liver lobe was performed in 5 horses. Three of those patients survived to discharge. CLINICAL RELEVANCE Results suggested that diagnosis of liver lobe torsion in horses may be difficult because clinical signs and results of laboratory testing are nonspecific and variable. Most affected horses had markedly abnormal peritoneal fluid. The prognosis for hepatic lobe torsion can be good, and early surgical correction is expected to improve outcome.