intestinal obstruction in small animals

Intestinal ObstructionManagement in Small Animals (Dogs & Cats)

General principles of small intestinal surgery

1. Fluid therapy

-In animals with obstruction, secretion of

fluid in to intestinal lumen is increased and

reduced absorption of intraluminal fluid and

electrolytes leads to reduction in intravascular

fluid volume results in dehydration

-if untreated dehydration result in

hypovolemic shock.

Fluid therapy…(continued)

• profuse vomiting may cause

hypochloremia,hypokalemia,or hyponatremia

• Loss of sodium, water, and bicarbonate rich pancreatic

secretion leads to metabolic acidosis.

• With high intestinal obstruction, excessive loss of gastric

hydrochloride from persistent vomiting may result in

metabolic alkalosis.

• Administer balanced electrolytes i/v .

• Crystalloid solution more common.

• If shock-colloids.

2.Antibiotic prophylaxis

• Indicated in animals with intestinal obstructions• Stagnant luminal contents and devitalized wall are

excellent growth media• Opening of intestine results in leakage of

microflora and contamination of surgical field.• Pathogens cause peritonitis after surgery are Escherichia coli Enterococcus Bacteroides Coagulase ‘+’ve Staph aureus• First generation cephalosporin is the choice.• Redosed 2 hours after the initial dose.

3.Assessment of intestinal Viability

1. Colour

2.Peristaltic waves

3.Vascular pulsations

-subjective factors.

Assessment of intestinal Viability….(continued)

• Fluoresceine dye

10 to 15mg /kg

Intravenously

Wood lamp

- mucosal viability

• Surface oximetry

- for assessment of perfusion.

Newer techniques include electromyography, Doppler ultrasonic flow

probes.

4.Choice of suture material for enteric closure

• Monofilament synthetic absorbable

( polydioxnone, polyglyconate) or non absorbable

(nylon or polypropylene).

• Chromic catgut-inflammatory process during its

dissolution and occurs more quickly when it is

exposed to proteolytic action of gastro-intestinal

secretions.

5.Choice of suture pattern for enteric closure

• Serosa

• Muscularis

•Submucosa

Holding layer, strongest

part,submucosal apposition

result in primary intestinal

healing

• Mucosa

6.Suture Line Reinforcement

• Omentum-called “abdominal police man”

-has an extensive vascular and lymphatic supply,angiogenic,immunogenic,and adhesive properties –control infection, restore blood supply and lymphatic drainage.

Serosal patch

• Used after intestinal surgery when closure

Integrity is questioned or dehiscence is repaired.

( in acute emergencies)

• The antimesenteric border of healthy jejunum

placed over the questionable suture line and is

sutured in place with simple interrupted suture.

• Provide support, a fibrin seal, resistance to

leakage, blood supply to damage area, may

prevent intussusceptions.

7.Anesthetic considerations

• Special consideration for patients with bowel

obstructions,ischemia,or perforations

• Enlarged viscera may compress vena cava-circulatory and

vascular compromise.

• Viscera displacing diaphragm cranially may compromise

respiration.

• Visceral manipulations may induce bradycardia.

• Maintain patients body temperature above 95 ° F

Surgical Anatomy

• Intestine of dog -5 times the body length(80% is small intestine).

• The duodenum is the most fixed portion(25 cm)

• The jejunum forms most of small intestine coils lying in the ventrocaudal addomen.

• The ilium-15 cm long and has an antimesenteric vessel.

• Cranial mesenteric artery is the major source of blood supply.

• Cranial aspect of duodenum receives its blood supply from gastro duodenal artery which originates from celiac artery.

• The innervations of small intestine is by autonomous nervous system.(Vagus and splanchnic nerves)

Intestinal obstruction

• Interruption in the passage of intestinal

contents

• Intestinal obstruction classified as-

Acute or Chronic

Partial or Complete

Simple or Strangulated

High or Low

Causes of obstruction

• Extraluminal

eg:-intussusception ,volvulus,hernia etc

• Intramural

eg:-intestinal neoplasia, hematoma,granuloma etc

• Intraluminal eg:-foreign objects

• Intestinal Pseudo-obstruction and ileus

Intestinal luminal obstructions

• Most common indication for laparotomy in dog and cat.

• Clinical signs associated with

location

duration

severity of obstruction

• vomiting, anorexia, depression and abdominal tenderness are common.

Pathophysiological events

Diagnosis

• History• Physical Examinations

• Radiography

The classic sign of mechanical obstruction is the presence of

multiple loops of gas-dilated small intestine of varying diameters

GI CONTRAST STUDY

• confirm suspect disease found onsurvey radiographs

.

Ultrasonography

Endoscopy

Surgical techniques

• Enterotomy

• Enterectomy

• Intestinal resection and anastomosis

• Enteroplication

Enterotomy

• Most common indication is intraluminal foreign body that cause obstructions.

• Intestinal biopsy

• Milk away intestinal content

• Doyen’s clamp

Enterotomy for intestinal biopsy

•Enterotomy incision may be

closed transversely.

Irreducible Intussusception

Mesenteric volvulus

Neoplasia

Intestinal resection and Anastomosis

Recommended for removing ischemic, necrotic segments of intestine.

End-to-end anastomosis is recommended.

Technique

• The affected segment is clamped

• The mesenteric vessels are ligated.

• The triangular piece of mesentery distal to ligature is torn and bowel is divided close to the clamp and removed

Stump closure End-to-end anastomosis

There are several ways to eliminate disparity between luminal diameters of the ends to be apposed.

1. Transecting smaller segment at an angle, creating a lumen of larger diameter.

Stump closure End-to-end anastomosis

2.To eliminate marked luminal disparity ,the antimesenteric border of the smaller segment can be incised longitudinally to create a larger opening.

The first and second sutures are placed in mesenteric and antimesenteric border

• 3.Spacing each suture farther apart on the large lumen side

Stump closure-End-to- end anastomosis-suture patterns

1.Single layer simple interrupted suture pattern.

2.Simple continuous suture.

3. Parker Kerr suture

-Temp.cont.suture over clamp

-The free ends of thread pulled and clamp withdrawn.

-united by Lembert’s suture

-ends of stay suture are drawn out.

4.Maunsell’s suture -M. suture at mesenteric borderBoth eversion and inversion technique.

One strand from the suture is used to insert an inversion suturearound half of the circumferenceof intestine to the antimesenteric border.

• The second strand is used to stitch the other half of the intestinal circumference.

• The knot is then tied to complete the inversion.

Maunsell’s Maunsell’s suture(contd….)suture(contd….)

•Criteria in assessing tech. of anastomosis-

1.Absence of leakage

2.Minimal occlusion of lumen.

3.Minimal formation of adhesions.

4.Fast rate of healing.

Enteroplication

• Prevent recurrence of intussusception

• Serosa-serosa adhesions are formed by suturing together adjacent loops of intestine.

Post operative Complications

• Septic peritonitis -associated with dehiscence of anastomosis or

enterotomy site.

-clinical signs occur 2-5 days after surgery.

-Diagnosis-serial complete blood count. increase in band neutrophils

-Broad spectrum antibiotics,fluids ,supportive therapy+ surgical correction Of primary problem.(serosal patch or omental patch)

-Complete drainage of peritoneal cavity.

• Adhesions

-in human patients

-Dogs &cats have active active fibrinolytic

system prevents this.

-Peritoneal irrigation with dialysis solution

after surgery reduce this.

• Short Bowel Syndrome -Few cases are reported. -Characterized by maldigetion and

malabsorption occur after extensive resection.• Ileus -Common complication -Reduced motility due to overactivity of

sympathetic system caused by manipulation of intestine, long operative time, and extensive resection.

Other causes of

Intestinal Obstruction

INTUSSUSCEPTION

• Intussuception is the telescoping or invagination of one intestinal segment (intussuceptum) in to lumen of an adjacent segment.

INTUSSUSCEPTION(contd…)

• Occur any where ;ileocolic and jejunojejunal intussusceptions are most common.

• Are often associated with enteritis (i.e, parasitism, viral or bacterial infections, dietary change, foreign bodies, masses) or systemic illness. In old animals -neoplasia.

• Also reported after environmental changes and surgery.

INTUSSUSCEPTION(contd…)

• More common in younger animals ( less than 1

year)

• Clinical signs vary with level and completeness of

the obstruction.

• It can progress to a point at which the small

intestine protrudes from anus and differentiated

from rectal prolapse by easy passage of probe

between the prolapsed segment and rectum.

• On palpation, a cylindrical mass in the cranial to mid abdomen.

• On plain radiograph, a mass effect or accumulation of gas proximal to intussusception.

• Manual reduction –if enteric

vessels are patent, intestinal wall

not look ischemic.• Gentle traction on intussusceptum

and pressure on intussuscepiens

Mesenteric volvulus

• Rare and fatal

• Intestine twists on its mesenteric axis, resulting in strangulating mechanical obstruction of S.I. and compression of cranial mesenteric artery and its branches

leading to ischemic necrosis.

Intestinal neoplasia

• Most often occur in rectum and colon in dog and small intestine in cat.

• Commonly affect muscular layer and cause mechanical obstruction.

• Most common is adenocarcinomas and lymphocarcinomas.