Segmental Jejunal Entrapment, Volvulus, and Strangulation Secondary to Intra-abdominal Adhesions in a Dog

Introduction

The more common causes of acute abdominal distress in dogs include gastritis, pancreatitis, and gastrointestinal foreign body obstruction.¹ Other differentials for acute abdomen include peritonitis, intussusception, and, rarely, mesenteric volvulus. With either mesenteric or intestinal volvulus, the intestines rotate around the mesenteric axis, causing vascular compromise.² The cranial mesenteric artery and its branches (i.e., the caudal pancreaticoduodenal, jejunal, ileocolic, and right and middle colic arteries) are all affected. As a consequence of vascular compromise, intestinal necrosis and subsequent release of toxins occur, leading to shock. Clinical signs observed in patients with mesenteric volvulus include weakness, tachycardia, hypothermia, and mucosal pallor. Sloughing of the intestinal mucosa also occurs. The prognosis is poor to grave if bacteremia has occurred as a result of bacterial translocation through the ischemic intestinal mucosa.³ This report describes a case of jejunal entrapment by a fibrous tissue band with associated (secondary) volvulus resulting in segmental jejunal necrosis in a dog. To the authors' knowledge, this is the first report of this potential postoperative complication.

Case Report

A 4 yr old, castrated male dachshund was referred to the University of Illinois Veterinary Teaching Hospital emergency service with a 12 hr history of lethargy, restlessness, a “hunched” posture, and a painful abdomen. The owner also reported episodes of nonproductive vomiting. The patient had a gastric foreign body surgically removed 2 yr previously. Abdominal radiographs were performed and supportive care was initiated by the primary care veterinarian prior to referral. The referral radiographs showed multiple round gastric foreign bodies approximately 3 mm in diameter. Mild distention of some loops of small intestine was also evident. On presentation, the dog was depressed, weighed 16.7 kg, and had a body condition score of 5/9. He was normothermic with a heart rate of 90 beats/min and a respiratory rate of 30 breaths/min. The mucous membranes were pink and moderately tacky. Pain was elicited on abdominal palpation, especially in the cranial abdomen. Oxygen saturation of hemoglobin was 98% and systolic and diastolic blood pressures (measured with an oscillometric blood pressure monitor) were elevated at 182 mm Hg (reference range, 100–165 mm Hg) and 119 mm Hg (reference range, 40–85 mm Hg), respectively. Packed cell volume and total solids were within normal limits at 53% (reference range, 36–53%) and 7.1 g/dL (reference range, 6–8 g/dL), respectively.

No abnormalities were noted on an electrocardiogram. A serum chemistry profile revealed a slightly elevated hematocrit (52%; reference range, 35– 51%), mild hyponatremia (145.5 mmol/L; reference range, 146.8–153.1 mmol/L), hyperglycemia (134 mg/dL; reference range, 83–112 mg/dL), and a decreased anion gap (10.0 mmol/L; reference range, 12.9–20.8 mmol/L). There was a mild hypoglobulinemia (2.6 g/dL; reference range, 2.7–4.4 g/dL) and an elevated albumin-globulin ratio (1.6; reference range, 0.6–1.1). The complete blood count revealed lymphocytosis (8,000/μL; reference range, 1,000–4,800/μL), monocytosis (2,000/μL; reference range, 200–1,400/μL), and eosinopenia (0/μL; reference range, 100–1,000/μL). The canine pancreatic lipase immunoreactivity snap test^a was normal. Urinalysis revealed alkalotic urine with a pH of 9.0 and a specific gravity of 1.040. There was a moderate amount of triple phosphate crystals.

Right and left lateral and ventrodorsal abdominal radiographs were repeated at the University of Illinois Veterinary Teaching Hospital. Six small (3–4 mm) radiopaque foreign bodies were present in the lumen of the stomach. A moderate amount of gas and fluid was present in the stomach and small intestines; both organs were dilated. There was a mild loss of serosal detail suggesting the presence of a mild amount of peritoneal fluid.

The dog had six radiopaque gastric foreign bodies that appeared to be small enough to pass through the gastrointestinal tract. Additional differentials included radiolucent gastric or intestinal foreign bodies, gastroenteritis, acute pancreatitis, or peritonitis. The radiographs did not indicate an obstructive pattern. It was decided to hospitalize the patient, provide supportive care, and continue to monitor for continued vomiting or worsening of the dog's clinical appearance. The dog was hospitalized, an intravenous (IV) catheter was placed, and lactated Ringer's solution^b supplemented with 16 mEq/L of potassium chloride was administered at a rate of 120 mL/kg/day. Buprenorphine^c (0.01 mg/kg IV q 6 hr) and intramuscular maropitant citrate^d (1 mg/kg q 24 hr) were administered for pain management and antiemesis, respectively.

The blood pressure was re-evaluated 12 hr later. The diastolic pressure remained elevated at 113 mm Hg, whereas the systolic pressure had decreased to 133 mm Hg. Abdominal radiographs 12 hr later remained unchanged compared with the previous radiographic findings. During the night, there was one episode of regurgitation that consisted of a small amount of brown liquid.

On the second day of hospitalization, the dog was reluctant to walk and his abdomen had become distended and was more painful on palpation. He had a bowel movement with frank blood and another episode of regurgitation. The packed cell volume and total solids were 50% and 6.1 g/dL, respectively. The chemistry panel revealed hyponatremia (144.4 mmol/L), decreased partial pressure of carbon dioxide in venous blood (42 mm Hg; reference range, 43.8–111.0 mm Hg), hypochloremia (108.7 mmol/L; reference range, 110.6–115.5 mmol/L), hypocalcemia (1.15 mmol/L; reference range, 1.18–1.35 mmol/L), and increased lactate (3.1 mg/dL; reference range, <2.5 mg/dL). The IV fluid administration rate was increased to 180 mL/kg/day.

Due to the patient's deteriorating condition, an exploratory celiotomy was performed. Perioperative ampicillin^e was administered (22 mg/kg IV q 1.5 hr). A standard ventral midline celiotomy was performed from the xiphoid process to 3 cm caudal to the cranial aspect of the prepuce. Abdominal effusion was observed and a sample was obtained for aerobic culture and sensitivity testing. A segment of approximately 30 cm of dark red to black small intestine was identified. A rotated mesentery that was apparently obstructing the blood flow supplying the affected segment of bowel was also noted. Several adhesions and fibrous bands were identified within the abdomen between viscera and from viscera to peritoneum, presumptively from the surgery performed previously (Figure 1). Because the stomach was distended, an orogastric tube was passed and the stomach contents were drained, allowing the foreign bodies to be palpated in the stomach. A jejunal resection and was performed taking care not to untangle the mesenteric vessels supplying the devitalized intestines. Approximately 30 cm of intestines were resected and removed from the abdominal cavity. An end-to-end anastomosis of the intestine was performed with a simple interrupted appositional pattern using 3–0 polydioxanone^f.

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A gastrotomy was then performed and a 3 cm × 3 cm black rubber foreign body, nine choke cherry pits, raspberries, and other pieces of ingesta were removed. The stomach was closed using a two layer closure. The mucosa and submucosa were apposed with a simple continuous pattern and the seromuscular layer was apposed with a Cushing's pattern using 2–0 polydioxanone^f. Intra-abdominal adhesions and fibrous bands were broken down using electrosurgery. The abdomen was irrigated with 2 L of warm saline prior to routine closure

After being resected, the segment of intestine was untangled. It was determined that there was a fibrous tissue band spanning a segment of jejunum. The affected segment had passed between the band and the intestine, becoming entrapped. At the site of the entrapment, the intestines and its mesentery had undergone volvulus, compromising the blood flow to the entrapped segment of jejunum. The excised tissues were submitted for histopathology.

Recovery from anesthesia and surgery was uneventful and IV fluids were continued at a rate of 120 mL/kg/day. Hydromorphone^g (0.1 mg/kg IV q 4 hr) was administered for analgesia. Enrofloxacin^h (20 mg/kg IV q 24 hr) and ampicillin^e (22 mg/kg IV q 8 hr) were administered for 3 days. Tramadolⁱ (3 mg/kg q 12 hr) and carprofen^j (2.2 mg/kg q 12 hr) were administered orally for 5 days starting 2 days after surgery for inflammation and pain management. The patient remained in the hospital for 9 days following surgery at the owner's request. The incisional sutures were removed at discharge and the incision appeared healed at that time.

Histopathology revealed focal circumferential constriction, necrosis, and degeneration of the jejunum, which was consistent with volvulus. There was wide-spread transmural intestinal hemorrhage and neutrophilic mesenteritis, which was likely a result of ischemic degeneration and necrosis secondary to the volvulus. The peritoneal fluid did not yield any bacterial growth.

At 2 mo and 3 mo postsurgically, the owners reported via telephone that the dog had been doing well, except for one episode of vomiting that they felt was a result of the dog eating too quickly. There had been neither restrictions nor changes in his normal activity and attitude.

Discussion

Previous case reports of either mesenteric or intestinal volvulus in dogs describe a rotation of the intestines around the root of the mesentery, resulting in ischemia and subsequent necrosis of the affected tissue.^2,4,5 Several etiologies for mesenteric or intestinal volvulus have been suggested, including treatment of worm infestation, lymphocytic-plasmacytic enteritis, ileocolic carcinoma, pancreatic insufficiency, intussusception, parvovirus infection, vigorous exercise, closed abdominal trauma, concurrent gastric dilatation and volvulus, and gastric foreign bodies; however, most cases are idiopathic.^5–9 When torsion persists, the affected intestinal wall becomes hypoxic, resulting in destruction of the mucosal barrier, allowing bacterial translocation and toxins to diffuse into the peritoneal cavity. The majority of tissue damage occurs when the previously ischemic tissue is reperfused, resulting in a reperfusion injury, which is characterized by oxygen-derived free radicals causing widespread tissue damage.^5,10 There is a higher incidence of intestinal volvulus in large breed dogs, especial German shepherd dogs, that initially have nonspecific gastrointestinal signs, such as restlessness, abdominal pain and distention, vomiting, and tenesmus.²

The case described herein is unique because it involved a focal area of the jejunum that was incarcerated in fibrous adhesions with volvulus and ischemic necrosis. It was hypothesized that the fibrous adhesions observed were secondary to the previous abdominal surgery for gastric foreign body removal performed 2 yr previously.

Any abdominal surgery will cause some trauma to the peritoneal lining and the serosa of viscera that can induce an inflammatory response.¹¹ The fibrin that is initially formed as a response to tissue insult functions to repair injured tissue and stabilize local organs and damaged serosal surfaces. These postoperative abdominal adhesions have a function in the healing process, but can also lead to increased postoperative morbidity and mortality if fibrinolysis does not subsequently occur. Several factors, such as ischemia, endotoxemia, intestinal manipulation, intestinal distention, and dessication of serosal surfaces, all reportedly contribute to the formation of adhesions.¹² Foreign body contamination, such as lint, cotton fibers, gauze fragments, glove powder, and antibiotic powder in the peritoneal cavity, also contribute to fibrin formation.

There is no published information in dogs describing postoperative morbidity secondary to adhesion formation and subsequent bowel entrapment. Postoperative adhesions in equine abdominal surgeries are common and of concern.¹³ In horses, intra-abdominal adhesions not only form at the surgical site, but also throughout the peritoneal cavity. Adhesions are the most common pathologic finding at repeat laparotomy in horses. The occurrence of intra-abdominal adhesions after small intestinal surgery in horses may be higher than 22%. Only adhesions involving the small intestine result in clinical signs.¹⁴ In one study examining the factors influencing postoperative survival in 140 horses, the most commonly reported cause of death or euthanasia after discharge was adhesions and repeated episodes of colic.¹⁵ One case report described a 4 mo old colt that presented for necropsy following a jejunocecostomy.¹⁶ Necropsy revealed volvulus of the jejunum that formed due to fibrous adhesions. That equine case is similar to the findings in the case described here. Due to the colt's age and history, the fibrous adhesions were determined to be secondary to the previous jejunocecostomy surgery.

In humans, it is well-recognized that postoperative abdominal adhesions lead to increased postoperative morbidity and mortality. Between 93% and 100% of patients that undergo transperitoneal surgery will develop postoperative adhesions.¹¹ Also, 86% of small bowel volvulus in humans is secondary to acquired lesions, such as postoperative adhesions.¹⁷

Postoperative intraperitoneal adhesions or bands are a life-long concern in humans, making this an area of active research.¹⁸ General principles of appropriate surgical technique, such as gentle tissue handling, hemostasis, tissue irrigation, minimal use of electrocautery, and small, nonreactive sutures, should be emphasized.¹⁹ In an analysis of risk factors, 66% of human patients with postoperative obstruction due to adhesions had undergone laparotomy, whereas only 34% had undergone laparoscopy.¹⁸ The extent of adhesions following laparoscopy in a canine model were found to be significantly less than following laparotomy, presumably due to the less invasive nature of laparoscopic surgeries.²⁰

Several experimental products and procedures have been evaluated in an attempt to decrease adhesion formation and subsequent mortality. Using barriers prior to closure in an attempt to eliminate postoperative adhesions is currently being explored in animal models for use in human surgery.²¹ These barriers are composed of glycerol, sodium hyaluronate, and carboxymethylcellulose. They are lightweight, tissue-like films that can be placed at the surgical site and throughout the abdomen. The theory is that they will protect tissue surfaces during healing and separate the tissue surfaces at areas where adhesions are likely to form. In the case reported here, the patient's abdomen was lavaged with 2 L of sterile saline. No additional treatments were used due to the low likelihood of serious consequences resulting from postoperative abdominal adhesions in dogs.

A generalized, gas distended intestinal pattern consistent with a paralytic ileus is a common radiographic finding with mesenteric volvulus.^2,5 In the dog described in this report, preoperative abdominal radiographs were not consistent with the reported abnormal findings in dogs with mesenteric volvulus. Abdominal ultrasound would likely have provided more preoperative information, but was not performed. An abdominal exploratory surgery was thought to be in the best interest of the patient due to the deterioration in the dog's status.

In humans, abdominal ultrasonography is considered an acceptable imaging modality for diagnosing intestinal entrapment and volvulus because of its noninvasive nature and diagnostic images, such as a whirlpool or baber-pole sign of volvulated bowel loops encircling the mesenteric vasculature.²² Color Doppler ultrasound can identify the location of and relationship between the mesenteric vein and artery, which can be diagnostic for midgut volvulus in humans.²³ Transverse sonogram can reveal the mesenteric vein going around the mesenteric artery in a clockwise or, less commonly, in a counterclockwise direction. The mesenteric artery is centrally located in this whirlpool-like image of the vessels.

In humans, computed tomography is the ideal diagnostic tool because it is fast and reliable.²² It can also demonstrate the characteristic whirlpool pattern described above. Other imaging modalities that have been used to diagnosis volvulus include gastrointestinal contrast studies, mesenteric angiography, and magnetic resonance imaging. A spiral configuration of jejunal loops can be observed with gastrointestinal contrast studies. Angiography will reveal a twisting mesenteric artery and magnetic resonance imaging will also show a mesenteric vein rotation and the characteristic whirlpool sign.

Conclusion

This is the first report of postoperative fibrous adhesions causing bowel incarceration and subsequent volvulus leading to necrosis of a segment of intestine in a dog. A segment of the jejunum was successfully resected without any postoperative complications. Care was taken not to untangle the ischemic tissue to minimize the risk of reperfusion injury. Segmental intestinal entrapment and volvulus secondary to intra-abdominal adhesions should be considered in any animal that presents with an acute abdomen and a history of previous abdominal surgery.