Step by step approach to the abdominal cavity in small animals – part 1 - Veterinary Practice
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Step by step approach to the abdominal cavity in small animals – part 1

CHIARA COSTA DEVOTI and JERRY O RIORDAN begin a twopart article on a surgical approach to the abdomen, outlining the reasons, the various considerations and thorough preparation required, the approach and exploration…

CELIOTOMY is commonly performed in veterinary practice; therefore, a systematic approach to the abdominal cavity is essential for every surgical-minded vet.

The term laparotomy refers to a flank incision while celiotomy is a more correct definition of a generic surgical approach to the abdomen: in reality both are used synonymously.


Celiotomy may be performed for a variety of reasons, both therapeutic and diagnostic.

  • Acute onset abdominal pain and findings suggestive of life-threatening abdominal pathology (GDV, intestinal obstructions and volvulus, etc.).
  • Abdominal trauma/foreign bodies.
  • Septic/aseptic peritonitis.
  • Haemoabdomen/internal haemorrhage in haemodynamic unstable patient.
  • Uroabdomen.
  • Pneumoabdomen.
  • Chyloabdomen.
  • Biopsies of abdominal organs (chronic pathologies of abdominal organs, staging of neoplasia, etc.).
  • Approach to the retroperitoneal space.
  • Reconstruction of abdominal wall defects and hernias.
  • Specialised surgery of the gastrointestinal tract, liver and pancreas, urinary system, reproductive system, haemolymphatic system.


All patients undergoing a celiotomy must be haemodynamically stable enough to go through anaesthesia. Therefore, compromised patients must be adequately stabilised before surgery.

While an explorative laparotomy represents a useful diagnostic tool, it must be performed only when extra-abdominal conditions have been ruled out. Inadequate surgical training and equipment also represent contraindications to surgery.

Pre-operative patient management

Pre-operative management depends on the underlying pathology. General indications are: performing an accurate general examination with special attention to the cardiovascular system; adequate diagnostic imaging work-up according to the initial presentation; placing of an intravenous catheter; blood works including a minimum of PCV, CBC, platelet count, total proteins, BUN and blood glucose; more biochemistry and clotting profiles according to the animal disease or if a coagulopathy is suspected; blood typing if an intra-operative haemorrhage is foreseen.

Anaesthetic/analgesic considerations

An anaesthetic plan must be organised according to the signalment, history, underlying disease process and ASA status classification. Appropriate analgesia is paramount. Pre-emptive and intra-operative analgesia may include opioids, ketamine, alpha-two agonists and local anaesthetics. Postoperative analgesia may include also NSAIDs.

Anaesthetic monitoring such as ECG, pulse oximetery, non-invasive or invasive blood pressure monitoring, capnography and body temperature monitoring are vital for debilitated patients. Mechanical ventilation may be required.

Surgical anatomy of the abdominal wall

The abdominal ventral wall is composed of an external and an internal leaf. The external leaf is formed by the aponeurosis of the external and internal abdominal oblique muscles and by the aponeurosis of the transversus abdominis muscle near the pubis.

The internal leaf is composed by a portion of the aponeurosis of internal abdominal oblique muscle, by the aponeurosis of the transversus abdominis muscle and by the transversal fascia. The internal leaf disappears in the caudal third of the abdomen.

Surgical instrumentation

A basic laparotomy tray should include: scalpel handle for 10 and 11 blades, needle holder (Mayo or Mathieu), Brown-Adson, DeBakey and thumb forceps, Allis tissue forceps, Babcock forceps, Halstead Mosquito and Rochester-Carmalt forceps (straight and curved), Metzenbaum and Mayo scissors (straight and curved), Doyen intestinal clamps, Balfour or Gosset self-retaining retractors, Senn-Miller or Faraboeuf manual retractor.

Also necessary are large laparotomy sponges, large and small swabs with radio-opaque markers, electrocoagulation,

suction and appropriate suture material. Sterile water-per injection or Hartmann’s must also be available to be warmed to flush the abdominal cavity if needed. Surgical instrumentation must be organised on the surgical tray before the first incision.

Patient preparation

The patient is placed in dorsal recumbence. The entire abdomen, including the inguinal area, the medial side of the legs and the caudal thorax must be clipped. The area clipped must be large enough to accommodate unforeseen complications and for expansion of the field if necessary.

The prepuce can be retracted to one side with a towel clamp but if left in the surgical site it must be flushed with an appropriate diluted antiseptic solution. The bladder should be voided prior to surgery and a urine sample obtained.

An initial layer of four drapes must be placed around the scrubbed area, and then a second bigger drape will cover all the exposed portion of the patient and the surgical table.

It is also possible to apply an antimicrobial adhesive drape to the site of the incision: this helps prevent leaking of fluid around the drapes.

All the swabs and sponges must be counted; they will be recounted before closure of the abdomen to verify that none has been left in the abdominal cavity.

Surgical approach to the abdominal cavity

  • Incise the skin on the ventral midline with a 10 blade scalpel, going from xiphoid process and extending caudally to the pubis. The incision must be long enough to permit a complete exploration of the abdominal cavity. In male dogs extend the incision around the prepuce cutting only through the skin to avoid damage to the external pudendal vessels. It is not possible to perform an exploratory laparotomy through a small excision.
  • With Metzenbaum scissors extend the incision to the subcutaneous fat. In cats the linea alba is easily identified once the subcutaneous fat has been trimmed. In dogs subcutaneous fat can obscure linea alba, therefore more dissection may be necessary (push-cut technique). Ligate or cauterise small subcutaneous vessels.
  • In the male dog, identify and transect the preputial muscle (the two ends of this muscle will be re-apposed during closure). Identify, ligate and transect the superficial branches of the pudendal muscle.
  • With the linea alba visible, tent it away from abdominal organs with thumb forceps. Holding the scalpel with the cutting edge facing up and parallel to the body of the patient, make a sharp incision into the linea.
  • With fingers or closed blunt forceps, palpate the interior surface cranially and caudally to verify there are no adhesions.
  • Use Mayo curved scissors or a blade to extend cranially and caudally the linea alba incision.
  • The falciform ligament cranially must be removed if it interferes with a complete exploration of the abdominal cavity. Its lateral attachments are transected and the base is ligated and removed.
  • Gosset retractors are essential to maintain exposure of the abdomen. Place moistened laparotomy sponges between the arms of the retractors and abdominal wall to protect tissue from excessive pressure, making sure no organs are caught in them.

Systematic exploration of the abdominal cavity

Systematic evaluation of all the abdominal contents must be performed in all cases. If fluid is present, samples must be obtained for evaluation.

If present, isolation and control of internal haemorrhage and gastrointestinal leakage must take priority. All organs must be gently manipulated and maintained moistened with laparotomy sponges or warm solution.

The abdominal cavity is divided into four quadrants and thoroughly explored. All organs are examined, paying attention to size, shape, colour, location and consistency. Normally the first thing seen on opening the abdomen is the greater omentum attached to the greater curvature of the stomach and covering the abdominal organs.

  • Cranial quadrant: exteriorise, inspect and palpate the two leafs of the greater omentum. With gentle traction, displace the liver and examine the diaphragm and the hiata. Evaluate and palpate all liver lobes. Inspect and express the gall bladder and check the integrity of the extra-hepatic biliary tree. Examine and palpate the whole stomach, the mobilisation of which is limited by the oesophagus and the pylorus. Inspect and palpate the duodenum and the duodeno-pancreatic vessels. The spleen can be examined in situ or completely exteriorised; check both surfaces for pulsation of the splenic artery. Inspect both the pancreatic limbs, handling it gently; to visualise the left, apply a gentle traction on the body of the stomach. Then examine the portal vein, the caudal vena cava and the hepatic arteries.
  • Caudal quadrant: inspect the descending colon and mesocolon. The urinary bladder should be emptied prior to surgery; applying traction to its pole, it’s possible to visualise also its dorsal face. Digitally, palpate and examine the intrapelvic urethra. By manipulating the urethra it’s possible to examine both lobes of the prostate. The uterine body and horns are deep in the abdominal cavity, in an extraomental position. Inspect the inguinal rings and the local vascularisation. Examine the rectum by applying gentle caudal traction on the descending colon.
  • Intestinal tract: the greater omentum is displaced cranially and the intestinal tract is examined starting from the duodenum. The jejunum and the ileum are elevated outside the abdominal cavity and palpated. Check the mesenteric vascularisation and lymph nodes. Mesenteric arterial pulsation and intestinal peristalsis must also be evaluated.
  • “Gutters”: use the mesoduodenum as an anatomical retractor to displace the intestines medially (left side of the animal) and examine the right abdominal contents. Palpate the kidneys and examine the adrenal glands, the ureter and the ovary if present. Inspect the renal artery and veins, following them till the caudal vena cava. Similarly, using the descending colon to retract the abdominal contents to the right side of the animal, inspect and palpate the left kidney, adrenal gland, ureter and ovary.
  • Part two will include indications and instructions as to how to obtain biopsies in the abdomen and closure of the abdomen.

References and further reading

Tobias and Johnston (2012) Veterinary Surgery: Small Animal, 1st ed.

Theresa Welch Fossum (2012) Small Animal Surgery, 4th ed.

Karen Tobias (2008) Manual of Small Animal Soft Tissue Surgery, 1st ed.

Moisonnier, Degueurce et Bougault (2008) Laparotomie exploratrice chez le chien, 1st ed.

Ettinger and Feldman (2010) Textbook of Veterinary Internal Medicine, 7th ed.

Tranquilli, Thurmon Grimm (2007) Lumb and Jones’ Veterinary Anesthesia and Analgesia, 4th ed.

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