Return to use and performance following exploratory celiotomy for colic in horses: 195 cases (2003–2010)

Reasons for performing study: There are few objective data on return to use and performance in horses following colic surgery. Objective: To investigate return to functional use of horses following colic surgery and factors associated with a negative outcome. Methods: The North Carolina State University Equine Colic Database was reviewed for horses that underwent exploratory celiotomy for colic (2003–2010). Horses were excluded from the study if they survived <6 months, had no intended use preoperatively, or if further data were not available at attempted follow‐up. Information retrieved included history, background, use, and selected pre‐, intra‐, and post operative factors. Telephone interviews were used to obtain follow‐up data. Logistic regression was used to investigate associations between clinical data and outcome, reported as odds ratios with a 95% confidence interval and corresponding P value. Results: Of patients surviving to 6 months, 133/195 (68%) were performing their intended use and 85/156 (54%) were at or above preoperative performance. At one year, 145/190 (76%) horses were performing their intended use and 101/153 (66%) were at or above preoperative performance. Animals were significantly less likely to return to use/performance if they had a previous celiotomy, stall rest for an orthopaedic condition, a nonstrangulating lesion type, incisional hernia, diarrhoea or laminitis. Conclusions: The overall prognosis for return to use and performance following colic surgery is fair to good. Multiple pre‐ and post operative factors may affect the likelihood of return to use and performance. Potential relevance: Targeted owner education regarding preoperative lameness, post operative rehabilitation and treatment for complications, such as incisional hernioplasty, may help inform owners about their horse's potential for return to use and performance following colic surgery.     

Anesthetic management of a white rhinoceros (Ceratotherium simum) undergoing an emergency exploratory celiotomy for colic

ObservationsA 26-year-old male white rhinoceros (Ceratotherium simum), weighing approximately 2000 kg was anesthetized for an exploratory celiotomy. Sedation was achieved with intramuscular butorphanol (0.04 mg kg^?1) and detomidine (0.025 mg kg^?1) and induction of anesthesia with intravenous glyceryl guaiacolate (50 g) and three intravenous boluses of ketamine (200 mg, each); the trachea was then intubated and anesthesia maintained with isoflurane in oxygen using a circle breathing system. Positioning in dorsal recumbency for the surgery and later in sternal recumbency for the recovery represented challenges that added to the prolonged anesthesia time and surgical approach to partially correct an impaction. The rhinoceros recovered uneventfully after 10.4 hours of recumbency.ConclusionsAnesthetic management for an exploratory celiotomy with a midline approach is possible in rhinoceroses, although planning and extensive staff support is necessary to adequately position the patient.     

Surgical treatment of colic in the miniature horse: a retrospective study of 57 cases (1993-2006)

REASONS FOR PERFORMING STUDY: It has been suggested that the rate of post operative abdominal adhesions in miniature horses is higher than that for other breeds. However, few reports exist in the veterinary literature describing complications and long-term survival following surgical treatment of colic in these horses. OBJECTIVES: To determine the prevalence of surgical lesions in miniature horses with acute abdominal disease in terms of clinical signs, surgical management, post operative treatment and complications, as well as short- and long-term survival. METHODS: Medical records of 57 American Miniature Horses undergoing surgical treatment for acute abdominal pain at the Michigan State University Large Animal Veterinary Teaching Hospital 1993-2006 were evaluated for clinical information. Owners and trainers were contacted to gain information regarding long-term survival. RESULTS: The most common surgical lesion was a faecalith (38/57 cases) located primarily within the descending colon and most frequently diagnosed in horses age <6 months (19/38 cases). Short-term survival to hospital discharge for horses recovered from anaesthesia was 98% (55/56) with the most common post operative complications being diarrhoea and inappetance. Intra-abdominal adhesions were identified in 2/8 horses requiring a second celiotomy. Long-term follow-up was available for 45 horses and 87% (39/45) were alive at least 12 months after surgery. CONCLUSIONS: As previously reported, faecalith obstruction is a frequent surgical lesion in the miniature horse and is most common in miniature horses age <6 months. The incidence of adhesion formation may be lower than previously reported.     

A giant nonstrangulating mesenteric lipoma as a cause of recurrent colic in a horse

Colic is a major cause of veterinary attendance in general practice and although most colic episodes remain isolated, recurrence may occur and definitive diagnosis can be difficult to obtain. This report describes an unusual presentation of a lipoma in a middle‐aged horse presented for recurrent colic. A massive lipoma causing a nonstrangulating space occupying obstruction of the small intestine was found during an exploratory celiotomy and was considered to be the most likely cause of the recurrent episodes of abdominal discomfort.     

Intramural jejunal leiomyoma as a cause of colic

A 15-year-old Thoroughbred gelding showjumper presented with colic after a history of chronic mild, intermittent colic. He was refractory to medical management. At surgery, he was found to have a 15-cm intramural mass in the distal jejunum, approximately 3 m orad to the ileum. Histopathology post-operatively revealed a leiomyoma. Leiomyomas in horses are rare. They have been reported most commonly in the reproductive tract, with other rare reports in the oesophagus and omentum. To the knowledge of the authors, there are no reports of identification and treatment of non-strangulating obstruction of the jejunum caused by a leiomyoma. The horse recovered from his surgery and went on to compete at the same level of showjumping as previous to the surgery with no further episodes of colic. Based on this report, leiomyoma should be a differential for small intestinal obstruction in the future.     

Pulmonary oedema associated with anaesthesia for colic surgery in a horse

A 506 kg Warmblood horse with colic was anaesthetized for exploratory celiotomy. Anaesthesia was complicated by arterial hypoxaemia which persisted throughout surgery from the induction of anaesthesia. After endotracheal extubation in the recovery box, a degree of airway obstruction probably occurred during a brief delay in naso-tracheal intubation. Signs of pulmonary oedema were seen shortly afterwards. Furosemide and oxygen were given. Arterial hypoxaemia was present [PaO2: 6.5 kPa (49 mmHg)] when FIO2 was an estimated 0.3. The horse recovered and stood after 45 minutes. It was re-anaesthetized 3 days later when arterial blood gas analysis did not reveal hypoxaemia. The horse was killed on this occasion; post-mortem examination revealed the presence of pulmonary oedema, which probably resulted from multiple causes.     

Fifty years of colic surgery

Colic surgery is one of few treatments in which a veterinarian can use a skill to save an animal's life from a deadly disease within a short timeframe. Unfortunately, such success is not achieved without considerable risk for surgical failure, which is responsible for most complications in the immediate post‐operative period. The last 50 years have witnessed considerable improvements in colic surgery, although a ranking of the most important ones might not meet with universal agreement. Teamwork plays a critical role in the final outcome, starting and finishing with the referring veterinarian and owner. These individuals are responsible for promptly transferring the horse to a surgical facility and then dealing with aftercare and delayed complications. The surgeon is responsible for the intervening steps, including the decision on the need for surgery, and works with the anaesthesiologist to help a metabolically challenged patient to tolerate surgery and anaesthesia. Although early referral and improved diagnostic procedures can have a positive influence on survival, perceived improvements in surgery and anaesthesia need to be reviewed with some circumspection. Although more rigorous definitions and statistical analyses used in recent studies can invalidate comparisons with older studies, complication rates appear to be on the rise, despite putative improvements in dealing with them. This trend tends to diminish the value of colic surgery through increasing costs, overreliance on post‐operative pharmacological management, growing pessimism, high rates of intraoperative euthanasia, and possibly reduced long‐term survival. Future efforts should address these concerns, mostly through emphasis on prompt referral, good surgical technique and reducing the cost of colic surgery to an affordable level that saves more lives.     

Removal of a nasogastric tube fragment from the stomach of a standing horse

An 82-cm fragment of nasogastric tube was removed from the stomach of an adult horse under standing sedation by use of an endoscope and electrocautery snare. This is the first report of successful non-surgical removal of a nasogastric tube fragment from the stomach of a horse.     

Clinical comparison of two regimens of lidocaine infusion in horses undergoing laparotomy for colic

ObjectiveTo compare, in horses undergoing laparotomy for colic, the effects of administering or not administering a loading intravenous (IV) bolus of lidocaine prior to its constant rate infusion (CRI). Effects investigated during isoflurane anaesthesia were end-tidal isoflurane concentration (Fe’ISO), cardiovascular function, anaesthetic stability and the quality of recovery.Study designProspective, randomized clinical study.AnimalsThirty-six client-owned horses.MethodsHorses were assigned randomly to receive lidocaine as a CRI (50 μg kg⁻¹ minute⁻¹) either preceded (LB) or not preceded (L) by a loading dose (1.5 mg kg⁻¹ IV over 15 minutes). Lidocaine infusion (LInf) was started (T0) within 20 minutes after induction of general anaesthesia and discontinued approximately 30 minutes before the end of surgery. Anaesthetic depth, Fe’ISO, intra-operative physiological parameters and quality of recovery were assessed or measured. Data were analysed using one-way anova, t-test, Fisher test, Wilcoxon and Kruskal–Wallis tests as appropriate (p < 0.05).ResultsMean ± SD Fe’ISO was 1.21 ± 0.08% in group LB and 1.23 ± 0.06% in group L. Heart rate was significantly higher in group L than in group LB at times T5-T15, T25, T35 and T95. No difference was found between groups in other measured physiological values, nor in any measure taken to improve these parameters. Recovery phase was comparable and satisfactory in all but one full term pregnant horse in group L which fractured a femur during recovery.ConclusionPreloading with a lidocaine bolus prior to a CRI of lidocaine did not influence isoflurane requirements, cardiopulmonary effects (other than a reduction in heart rate at some time points) or recovery compared to no preloading bolus.Clinical relevanceA loading dose of lidocaine prior to CRI does not confer any advantage in horses undergoing laparotomy for colic.     

Molecular insights into dietary induced colic in the horse

Equine colic, a disorder manifested in abdominal pain, is the most frequent cause of emergency treatment and death in horses. Colic often requires intestinal surgery, subsequent hospitalisation and post operative care, with a strong risk of complications arising from surgery. Therefore strategies that explore approaches for preventing the condition are essential. To this end, a better understanding of the factors and mechanisms that lead to the development of colic and related intestinal diseases in the horse allows the design of preventive procedures. Colic is a multifactorial disorder that appears to be induced by environmental factors and possibly a genetic predisposition. One factor that seems to influence the risk of developing colic is the excessive consumption of diets containing high levels of carbohydrates. Therefore, major efforts have been made by various laboratories and institutions across the world to study the type and digestibility of various feed in order to formulate accurate and safe feed components and proportions. However, relatively little work has been carried out to characterise, in detail, the carbohydrate digestive and absorptive capacity and mechanisms underlying the potential adaptive response of equine gut epithelium to a changing diet. This review focuses on advances made towards understanding the molecular and cellular mechanisms involved in digestion and absorption of dietary carbohydrates in the equine gastrointestinal tract and the implication of these processes for the whole body physiology. It addresses the underlying mechanisms that may govern the adaptive response of equine small intestine to increased dietary hydrolysable carbohydrates. Furthermore, it describes changes that occur in the equine large intestinal microbiology and host tissue biology brought about by alterations in diet and in colic. It is hoped that a better understanding of the molecular and cellular processes that play important roles in the physiology and pathology of the equine gastrointestinal tract will assist the development of effective strategies to prevent equine colic.     

Congenital hypoplasia of the dorsal colon in a Quarter Horse filly with chronic,intermittent colic

Congenital colonic anomalies are rare in the horse and, to the authors' knowledge, no cases have been reported that include measurements of each segment of the large colon to confirm which section is abnormal. This case report describes chronic, intermittent colic in a Quarter Horse filly that had been attributed to chronic idiopathic hepatitis prior to an exploratory laparotomy. A colonic anomaly discovered at surgery became the primary differential for aetiology of the intermittent colic. Euthanasia of the filly and necropsy allowed further examination of the anomaly, where it was determined that the dorsal colon was short compared to the ventral large colon. In addition, the diagnosis of chronic idiopathic hepatitis was confirmed.     

Risk factors for epiploic foramen entrapment colic in a UK horse population: a prospective case-control study

REASONS FOR PERFORMING STUDY: Epiploic foramen entrapment (EFE) is a common cause of small intestinal strangulation in the horse and its epidemiology requires further investigation. OBJECTIVES: To identify horse- and management-level risk factors for EFE and to explore reasons for the apparent seasonality of this condition. HYPOTHESIS: Horses exhibiting certain behaviours and those exposed to particular management practices that vary seasonally are at increased risk of EFE. METHODS: A prospective unmatched, multicentre case-control study was conducted over 24 months in the UK. Data on 77 cases and 216 control horses were obtained from 9 collaborating clinics and logistic regression was used to identify associations between horse and management variables and the likelihood of EFE. RESULTS: In a final multivariable model crib-biting/windsucking behaviour was associated with the largest increase in likelihood of EFE. A history of colic in the previous 12 months, increased stabling in the previous 28 days and height of the horse also increased the likelihood of EFE. Horses with access to a mineral/salt lick, those easily frightened and horses not fed at the same time as others were at reduced risk of EFE. CONCLUSIONS: Horses exhibiting certain behaviours, those with a previous history of colic and horses of greater height appear to be at inherently greater risk of EFE. The increase in likelihood of EFE with increased duration of stabling may explain the apparent seasonality of this condition.     

Standing flank laparotomy for the treatment of small colon impactions in 15 ponies and one horse

Impactions are the most common problem affecting the small colon in horses and are much more prevalent in ponies and miniature horses. Ventral midline laparotomy under general anaesthesia is the standard of care for this condition when medical management fails to resolve the impaction or when the impaction causes complete intraluminal obstruction and tympany. This case series reports the use of standing flank laparotomy (SFL) in 15 ponies with focal small colon impactions and one large breed horse with an elongated small colon impaction. All cases presented with signs of colic of 1–4 days' duration. The horses were initially vigorously treated with both enteral and parental fluids but failed to pass faeces, with no resolution of abdominal distention or pain. In all cases, a definitive diagnosis was made during SFL and the small colon appeared to be viable. The impaction was resolved by extraluminal massage. In the horse and in one pony, in addition to extraluminal massage, high enema was administered during surgery. Routine perioperative treatment with fluids, analgesics, antimicrobials and wound care was provided. All animals survived to discharge. The time from surgical resolution of the impaction to passing faeces was less than 2 h in all but one case. Median duration of hospitalisation was 2 days and all animals returned to their original use by 2 months. The encouraging results of this case series suggest that SFL is a viable alternative to ventral laparotomy for ponies and horses with either focal SCI or extensive SCI.     

Acute hindlimb paresis caused by extension of a peripheral nerve sheath tumour into the spinal canal of a horse

A 10-year-old Quarter Horse gelding presented for a large, slowly growing mass in the right thoracic region caudal to the withers (approximately at the level of thoracic vertebrae 10 to 16). The mass was surgically removed, the horse returned to normal riding activity, and no external regrowth was observed. Two years after surgery, the horse developed progressive signs of hindlimb weakness, ataxia and adopting a dog-sitting stance. Post-mortem examination confirmed spinal canal infiltration and spinal cord compression (at the level of the 12th thoracic vertebra) by a similar soft tissue sarcoma as diagnosed previously. Immunohistochemistry confirmed the tumour as a peripheral nerve sheath tumour (PNST) likely originating from the twelfth thoracic spinal nerve. This report demonstrates that with incomplete tumour resection, local recurrence and extension of a PNST into the central nervous system can occur even years after initial tumour removal. Immunohistochemistry to differentiate the type of soft tissue sarcoma in cases with close association to the nervous system may prove beneficial to anticipate this uncommon complication. Early surgical resection with adjunctive therapies should be considered in these cases.     

Use of ultrasound to evaluate outcome following colic surgery for equine large colon volvulus

Reasons for performing study: The post operative response of the large colon wall after a surgically corrected large colon volvulus (LCV) has not been investigated. Objectives: To use transabdominal ultrasound to monitor the post operative change in large colon wall thickness following surgical correction of LCV. Hypothesis: A prolonged period to colon wall involution is correlated with an increased rate of post operative morbidity and mortality. Methods: A prospective clinical study including horses that presented to the North Carolina State University Veterinary Teaching Hospital for colic between September 2006 and March, 2008, had surgically diagnosed and corrected LCV (at least 360°) without resection and recovered from anaesthesia. Ultrasound of the ventral large colon was performed at the time of anaesthetic recovery and every 6–8 h until the colon wall returned to normal thickness (≤5 mm). Outcome was evaluated using a one‐way ANOVA to compare average time to colon wall involution between: 1) survivors and nonsurvivors; and 2) horses that developed multiple organ dysfunction syndrome (MODS) during the post operative period and those that recovered without evidence of MODS. Results: Sixteen horses that recovered without evidence of MODS had a significantly shorter period to colon wall involution (≤5 mm) compared to those diagnosed with MODS (mean ± s.e. 19.6 h ± 2.5 and 39.7 h ± 6.7 respectively, P = 0.006). There was no significant difference in mean period to colon wall involution between survivors and nonsurvivors (26.2 ± 4.9 and 33.2 ± 7.8 h, respectively). Conclusions: A shorter time to colon wall involution was associated with decreased post operative morbidity in horses presented for surgical correction of large colon volvulus without resection. Potential relevance: Ultrasonographic monitoring of colon wall involution after surgical correction of LCV may aid in identifying those cases at risk of MODS. Further investigation of colon wall involution time using a larger number of horses is warranted.