The Equine Gastrosplenic Ligament: Anatomy and Clinical Considerations L
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EQUINE VETERINARY EDUCATION / AE / JANUARY 2013 15 Case Report The equine gastrosplenic ligament: Anatomy and clinical considerations L. Hunt*, E. Paterson†, H. Sare‡, C. Kearney, H. McAllister and F. David UCD Veterinary Hospital, School of Veterinary Medicine, University College Dublin, Dublin 4, Ireland; †Boswall Loan 5, Edinburgh, UK; and ‡Klinik fur Anasthesiologie and Perioperative Intensivmedizin, Veterinarmedizinische Universitat Wien, Vienna, Austria. *Corresponding author email: [email protected] Keywords: horse; gastrosplenic ligament; rent; colic; small intestine; abdominal ultrasound Summary Case description A gelding was referred for colic and inguinal wound evaluation. A 9-year-old Thoroughbred cross gelding was presented to our Abdominal ultrasound showed distended, oedematous and hospital for investigation of colic of 8 hours’ duration. The signs immotile small intestine abaxial to the spleen. An exploratory of pain had increased despite administration of nonsteroidal laparotomy revealed jejunal incarceration through a rent in the anti-inflammatory drugs by the referring veterinarian. gastrosplenic ligament (GSL). The rent in the GSL was opened On presentation the horse was in good body condition, and surgical correction (resection and anastomosis of weighing 584 kg, and was of dull mentation. Heart and nonviable jejunum) performed. The GSL was left open. The horse respiratory rates were elevated at 52 beats/min and 20 recovered uneventfully and one year after surgery no further breaths/min, respectively. Mucous membranes were pink episodes of colic have been observed. and slightly tacky, with a capillary refill time of 3 s. Intestinal borborygmi were absent in all abdominal quadrants on auscultation. Passage of a nasogastric tube did not reveal Introduction any net gastric reflux; however, a large volume of gas was Incarceration of the small intestine through a rent in the relieved. gastrosplenic ligament (GSL) represents only a minor A deep laceration, which had occurred 4 days previously proportion of all small intestinal colics. It is reported to account as a result of a hunting accident, was present in the right for 4.5% of all small intestinal lesions, with a prevalence of inguinal region. Primary closure of the wound had been 1.5% of all horses undergoing exploratory laparotomy in performed by the referring veterinarian. This had largely one report (Jenei et al. 2007). Previous reports suggest that dehisced and a large amount of malodorous, purulent geldings are predisposed to the condition (Yovich et al. 1985; material was discharging from the wound. Multiple loops of Marien and Steenhaut 1998; Rhoads and Parks 1999; Jenei distended small intestine were present in the mid caudal et al. 2007). abdomen on palpation per rectum. In addition, an The GSL is a broad, thin band of omentum that runs from accumulation of retroperitoneal fluid and air in the right the left part of the greater curvature of the stomach to the inguinal area (which extended cranially) could be cranial edge of the spleen (Budras et al. 2003). Ventrally, the appreciated. GSL is continuous with the greater omentum. The blood supply A complete ultrasonographic examination of the to the ligament is provided by the gastroepiploic artery, which abdomen was performed (Reef 1998) using a 3.5 MHz is split into left and right arteries (Budras et al. 2003). The role of curvilinear transducer (Sonoace Pico)1. Multiple loops of small the GSL is unclear, but it may provide structural support to the intestine were seen in the left inguinal region and along the abdominal organs and viscera (Barone 1997). In the normal ventral abdomen. Most of the small intestinal loops in this horse no small intestine lies abaxial to this ligament (Yovich region were normal in size and wall thickness. However, et al. 1985; Rhoads and Parks 1999). multiple loops of immotile, distended small intestine were seen To the authors’ knowledge, there are no specific between the left body wall and the spleen (Fig 1). Small preoperative findings that indicate the presence of an intestinal wall thickness was also increased (1.29 cm, normal entrapment of small intestine through a rent in the GSL and the <0.3 cm, Reef 1998). The right inguinal area was difficult to diagnosis is usually made during surgical exploration of the evaluate due to the presence of air in the tissues creating abdomen or at necropsy (Marien and Steenhaut 1998). artefacts. A moderate amount of peritoneal fluid was seen Typical management of these cases involves manual traction in the cranioventral aspect of the abdomen. Turbid, and reduction of the incarcerated intestine through the GSL serosanguinous fluid was yielded readily on abdominocentesis (Jenei et al. 2007). This report describes the ultrasonographic and based on this appearance, samples were submitted for findings that led preoperatively to a suspicion of entrapment both cytology and bacterial culture. Total protein level was of small intestine through a rent in the GSL and some variations 38 g/l (reference range [rr] <20 g/l) and the white blood cell in the surgical technique used to reduce a portion of count was 0.32 ¥ 109/l (rr <5 ¥ 109/l) with 74% neutrophils. No incarcerated jejunum through a tight rent in the dorsal portion bacteria were observed on cytological evaluation and no of the GSL. In addition, a description of the normal anatomy in bacterial growth was yielded after 7 days of culture. the gastrosplenic region is given to help further treatment of A complete blood count (CBC) showed a mild lesions involving this area. leucocytosis (11.2 ¥ 109/l, rr 5.5–9.2 ¥ 109/l) with a mature © 2012 EVJ Ltd 16 EQUINE VETERINARY EDUCATION / AE / JANUARY 2013 administered over 45 min. CSL fluids at twice maintenance level (100 ml/kg bwt/day) were administered thereafter. Crystalline penicillin (22,000 iu/kg bwt i.v.), gentamicin sulphate (6.6 mg/kg bwt i.v.) and subcutaneous tetanus antitoxin were administered prior to surgery. The gelding was premedicated with xylazine (0.3 mg/kg bwt i.v.) and butorphanol (0.01 mg/kg bwt i.v.). Anaesthesia induction was achieved with administration of ketamine (2 mg/kg bwt i.v.) and diazepam (0.05 mg/kg bwt i.v.). A 30 mm diameter endotracheal tube was placed and anaesthesia was maintained with isoflurane in oxygen using positive pressure ventilation. CSL fluids, supplemented with 20 mEq of KCl/l, were administered i.v. throughout surgery. Dobutamine was administered at 0.1–0.4 mg/kg bwt/min to maintain mean arterial blood pressure at approximately a) 70 mmHg. Four litres of plasma (Hypermune)2 and 2 litres of 6% hetastarch (Voluven)3 were administered during surgery due to a worsening of the hypoproteinaemia. Lidocaine was given as a loading dose (1.3 mg/kg bwt i.v. over 10 min), followed by a continuous rate infusion (CRI: 0.05 mg/kg bwt/min i.v.); 1 which was discontinued 30 min prior to the end of surgery. 5cm Morphine (0.1 mg/kg bwt i.v.) was administered at the end of surgery. Urine output was also measured during anaesthesia 2 (2.5 ml/kg bwt/h). 2 The horse was positioned in dorsal recumbency. The 10cm * abdomen was clipped and an aseptic preparation performed using a chlorhexidine based scrub4. A 30 cm ventral midline * incision was made through the linea alba to access the 3 15cm abdomen. Abdominal exploration revealed a rent in the dorsal portion of the GSL. A right-to-left (caudal to cranial) herniation of jejunum through the rent was palpable. Despite multiple attempts, manual reduction (including enlargement b) D0 1.29cm Mean 1.29cm of the rent), was not possible as the ileum and caecum were Fig 1: (a) Schematic diagram showing position of ultrasound probe also displaced and pulled cranially. The GSL was transected on cranioventral aspect of left flank, where (b) was obtained in this parallel to the gastroepiploic arteries using the Ligasure Vessel 5 case. (b) Transabdominal preoperative ultrasound image of the Sealing System (Ligasure-8) in a ventral to dorsal direction, cranioventral aspect of the left flank showing distended, thickened until the rent was reached (Fig 2a and d).A6mlength of loops of small intestine between the lateral surface of spleen and jejunum were deemed nonviable and a resection was the body wall. This finding was strongly indicative of small intestine undertaken. An end-to-end jejunojenunal anastomosis was incarceration through the GSL. 1) Retroperitoneal fat; 2) distended performed using a one layer Lembert suture pattern (Nieto and thickened loops of small intestine; 3) spleen. The peritoneum is et al. 2006) using USP 3-0 polydioxanone (PDS) on a 36 mm, indicated with arrowheads, the lateral capsule of the spleen by half-circle round-bodied needle. asterisks. In the caudal abdomen, an area of fluid and crepitus was present on the peritoneal surface overlying the right inguinal neutrophilia (6.72 ¥ 109/l, rr 2–6 ¥ 109/l) and a left shift with band wound. No direct communication between the wound neutrophils (2.69 ¥ 109/l, rr 0–0.1 ¥ 109/l). Fibrinogen was and abdomen was identified on palpation and no other elevated at 6 g/l (rr 1–4 g/l). All other parameters were within abnormalities of the intestines or diaphragm were evident on normal limits. Biochemistry revealed a hypoproteinaemia exploration. No attempt was made to close the transected (54 g/l, rr 57–79 g/l) with a mild hypoalbuminaemia (28 g/l, GSL due to poor access and friability. The abdomen was rr 29–37 g/l); in addition to an elevated creatinine kinase lavaged with 10 litres of CSL fluid and the abdominal incision (826 iu/l, rr 0–70 iu/l), slightly increased creatinine level routinely closed in 3 layers. The linea alba was closed with (199 mmol/l, rr 100–170 mmol/l) and mildly increased bilirubin USP 6 polyglactin 910 (Vicryl) and the subcutaneous layer (60 mmol/l, rr 5–51 mmol/l).