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Surgical treatment of colic
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Veterinary Medicine
Graduate
02/29/2016

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Cards

Term
Colic surgery indications
Definition

 

Any lesion that will not resolve with medical treatment alone. ref. medicine notes and see site specific lesions below.

Term
approach to a colic surgery
Definition

 

generally ventral midline laparotomy incision under GA

Term
the stomach
Definition

 

The equine stomach capacity approx. 15L, not possible to exteriorise the stomach at surgery, but impactions can occasionally be surgically treated.

1. pyloric stensosis

2. Gastric impaction/dilatation  

Term
pyloric stenosis
Definition

rare

 

Foals up to 4 months; congenital (rare) or acquired (secondary to gastroduodenal ulcerationhealing by fibrosisstricture formation). Diagnosis: contrast radiography shows delayed outflow. Treatment = pyloromyotomy or bypass the pylorus with a gastrojejunostomy. 

Term
Gastric impaction/dilatation (adults)
Definition

 

Aetiology unclear - ?due to ingestion of unsuitable feed (coarse, dry), primary motility problem or secondary to liver disease. Diagnosis very difficult often made at surgery. Surgical evacuation may be attempted but the risk of abdominal contamination is high because the stomach cannot be isolated outside the abdomen. Spontaneous rupture may occur. 

Term
SMall intestine lesions
Definition

Non strangulating lesions: 

1. Ileal/jejunal impaction

2. intestinal neoplasia

3. anterior enteritis

Strangulating lesions

1. pedunculated lipoma

2. small intestinal volvulus

3. intussusceptions

4. thromboembolic colic

5. SI entrapment 

Term

 

1. Ileal/ jejunal impaction 

Definition

 

May occur in association with certain diets (e.g. Bermuda grass hay in the US) or with severe Ascarid infestation in young horses or possibly related to tapeworm burden. Treatment = decompression (via enterotomy if required). Prognosis = good. 

Term

 

2. Intestinal neoplasia 

Definition

 

Tumours of the GIT thickening of the intestinal wall complete/partial obstruction. Lymphosarcoma = most common. Weight loss often also present. If focal can resect affected portion of gut. Often multifocal resection not possible. Long-term prognosis usually poor. 

Term

 

3. Anterior enteritis

Definition

 

Aetiology unknown - ?salmonella/clostridia/diet? marked distension of proximal SI and stomach, may resemble a surgical colic . Treatment: medical = repeated nasogastric intubation or surgical = manual decompression of SI. Prognosis: 50-70% survival. 

Term

 

Strangulating obstructions of the small intestine 

Definition

 

Once cause ascertained treatment usually involves reduction of the strangulation + resection of ischaemic gut followed by anastomosis of proximal and distal portions of gut
i.e. end to end or side to side: jejuno-jejunostomy, jejuno-ileolstomy, jejuno-caecostomy. Prognosis depends on length of gut affected, duration of obstruction and consequent cardiovascular/endotoxaemic status of horse and lesion type but around 60-85% survival. 

Term
surgery specific SI anatomy
Definition

 

Duodenum (1m) attached to right dorsal body wall by a short mesoduodenum preventing exteriorisation. Jejunum=15-30mlong,long(50cm)mesojejunumcanexteriorise. Ileum(70- 80cm) has slightly thicker wall (more muscle) and a distinctive antimesenteric band (ileocaecal fold dorsal taenia of caecum) and although short, is commonly involved in surgical colics. The distal ileum and ileocaecal junction cannot be exteriorised. 

Term
pedunculated lipoma
Definition

 

Most common cause of SI strangulation, especially in mature/obese animals. Lipoma is often suspended on a single fibrous band attached to the mesentery encircles a bowel segment strangulates intestinal vasculature. 

Term

 

 Small intestinal volvulus 

Definition

 

Rotation of some/all of jejunum about its attachment in the dorsal abdomen at the cranial mesenteric arterial root. Often severe pain and poor prognosis due to amount of gut affected. Volvulus may be secondary to other lesions causing SI distension. 

Term

 

3. Intussusceptions 

Definition

 

Invagination of the proximal intussusceptum into the distal intussuscipiens initially simple obstruction, then strangulating as more gut entrapped and arterial supply is drawn in. May involve any segment of bowel but jejuno-jejunal intussusceptions more common in foals. Ileo-caecal intussuceptions associated with tapeworm infestation (Anoplocephala perfoliata) may require bypass of the ileo-caecal junction. 

Term

 

4. Thromboembolic colic 

Definition

 

Mesenteric vascular thrombi = result of the migration of Strongylus vulgaris larvae vascular infarction of a segment of SI which can be extensive. These lesions, formerly the most common cause of SI colics have become rarer since the widespread use of avermectin parasiticides. 

Term

 

SI Entrapment: 

Definition

 

  • Epiploic foramen entrapment: boundaries = caudal vena cava, caudate lobe liver, pancreas,

    (hepatic portal vein). Often hard to diagnose because entrapped gut is cranial to the liver

    may be no abnormal rectal findings and normal peritoneal tap


  •   Inguinal/scrotal hernia: usually breeding stallions. Swollen inguinal region. Palpate SI

    entering inguinal ring per rectum.


  •   Herniation through a mesenteric rent: ?spontaneous rent or broodmare after parturition

    (foetal foot)


  •   Gastro-splenic ligament: rare


  •   Umbilical hernia: up to 15% of umbilical hernias may SI strangulation

  •   Diaphragmatic hernia: rare ?congenital or after major traumatic episode. 

Term
caecum
Definition

 

  1. Surgery specific Caecal Anatomy:
    Only apex and part of body exteriorisable at laparotomy. Often used as ‘starting point’ for exploring abdomen. Dorsal bandileo-caecal fold. Lateral bandventral colon. 

Term
caecal impaction
Definition

 

  1. Primary impaction or secondary to motility disorder, common in hospitalised patients e.g. after GA or repeated sedation. Diagnosis + medical treatment see medicine notes. Surgery indicated if no response to medical treatment because the caecum is prone to spontaneously rupture (death).

    Surgery = evacuation via an apical typholotomy often recurs if primary motility problem.

    Caecocaecal and caecocolic intussusception +/- caecal bypass (ileocolostomy) because condition 

Term

 

Caecocaecal and caecocolic intussusception 

Definition

 

Caecocaecal intussusception (usually starts at apex) does not cause a total obstruction unless it progresses to obstruct the caecocolic area, at which point it is a simple obstruction. Further progression caecum can pass through into the RVC + draws in the caecocolic artery strangulating lesion. A firm mass may be palpable per rectum in the caecal base in some cases. Often initially present with mild to moderate pain, and progress slowly until complete obstruction occurs; at which point more rapid deterioration. Treatment of caeco-caecal = simple reduction if little damage, partial typhylectomy. Treatment of caeco-colic = enterotomy in the RVC and resecting the inverted caecal ischaemic stump from within the lumen (v.messy!) + jejunocolic anastamosis. 

Term

Colon Surgery specific Anatomy


Definition

 

CaecumRVCLVCLDCRDCtransverse colonsmall colon
Origin of RVC firmly attached proximally to the fixed caecal base, and RDC to the dorsal body wall i.e. these portions not exteriorisable at surgery. Left colons = highly mobile
displacements and torsions occur commonly.

N.B. Distension/secondary impaction of the large colon occurs secondary to most colonic disorders and evacuation of the colon is commonly indicated to ease manipulation of the colon and may improve post-operative motility. This is usually performed via an enterotomy at the pelvic flexure. 

Term

 

Large colon displacements N.B. see medicine notes on these conditions 

Definition

 

Causes: gaseous distention, transient motility disorders, sudden dietary changes, parturition, idiopathic. 

Term

 

  • Left dorsal displacement (aka nephrosplenic entrapment):  

Definition

 

  • Colon becomes entrapped between dorsal aspect of spleen and nephrosplenic ligament adjacent to the left kidney. Total or partial (simple) obstruction and variable pain. Diagnosis + medical treatment: see medicine notes. Severe cases with secondary impactions which do not respond to medical tx need surgery to reduce displacement. The prognosis is generally good. 

Term

 

  • Right dorsal displacement  

Definition

 

  • The left colons migrate around the body of caecum (clockwise or anticlockwise). Diagnosis and medical treatment: see medicine notes. Indication for surgery = unremitting pain, increasing distension, deteriorating CV status (some cases progress to colonic volvulus). If no volvulus, good (70-80%) prognosis of success. Colopexy to the abdominal wall can be performed if colon displacement recurrs (breeding mares) but has high rate of complications (wt loss, chronic colic, colon rupture). 

Term

 

  1. Colon volvulus/torsion 

Definition

 

  1. Torson often around caecolic junction whole colon involved. Can be 180 degrees (possibly non strangulating) to 360 degrees (strangulating) Extremely painful, rapidly deteriorating patient due to massive endotoxaemia. Treatment = surgical correction +/- colonic resection (if neccessary). If survive surgery, prone to acute colitis + systemic effects of endotoxaemia postoperatively. The prognosis is guarded unless surgically treated early 

Term

 

  1. Enterolithiasis 

Definition

 

  1. rare in the UK. Mineralised enteroliths tend to obstruct narrow transverse colon. Tx = Surgical removal of the enteroliths via an enterotomy carries a good prognosis. 

Term

 

Atresia coli 

Definition

 

A heritable congenital condition of foals, which results in atresia of a segment of colon and/or atresia ani. Diagnosis = contrast radiography, surgical correction possible if segment missing is not too long. 

Term

 

Small colon impaction 

Definition

 

Focal enterolith (US) or primary motility dysfunction, ? assoc. with Salmonellae?. Tx=manual decompression or enterotomy at surgery. 

Term

 

Rectal prolapse 

Definition

 

Graded 1-4 in increasing severity, grades 3 and 4 guarded prognosis because mesorectum tears. Tx: Mild = clean, resect affected mucosa + replacement, provided the seromuscular layer is intact. Prolapse > 25-30 cm probable mesocolon rupture, more aggressive surgery - refer. 

Term

 

Rectal tears 

Definition

 

Usually occur during rectal palpation. Graded 1-4, depending on the depth: grade one = mucosa only, grade 2 = muscularis only, grade-3 = mucosa and muscularis and grade 4 tears involve all layers, and result in abdominal contamination with faeces = life threatening. Most important step is to realise and identify the lesion early, report it to the owner, institute appropriate first aid + refer if necessary. It is very unadvisable to attempt to cover it up.

First aid = sedate, give epidural or large volume of local anaesthetic per rectum, careful evacuation and packing of the rectum to prevent further contamination, broad-spectrum antibiotics non steroidal anti- inflammatories, then referral/surgery in the case of severe lesions. Grade 3 and 4 lesions carry a guarded but not hopeless prognosis. Surgical management of severe lesions = temporary colostomy, temporary rectal liners or attempted primary surgical repair of the tear. 

Term

 

Repeat episodes of colic:

Definition

 

Common, especially in first year post surgery. Severity varies markedly. May require repeat laparotomy. 

Term
Ileus
Definition

 

Ileus:

Prevalence = 20%. Ileus (lack of peristalsis) may result from inflammation (peritonitis, handling at surgery, systemic effects of endotoxaemia), distension (obstructive problem e.g. at anatomosis site) or denervation (grass sickness). Ileus further distension and pain + dehydration if SI or impaction if LI affected. Diagnosis: rectal or abdominal ultrasound distended loops of SI with little movement, nasogastric intubationreflux. Treatment = reflux as necessary, supportive therapy, motility stimulants (e.g. lignocaine, cisapride, metaclopramide). Stomach may rupture if not refluxed regularly. 

Term

 

Incisional drainage/infections/herniation: 

Definition

 

Prevalence = 10-40%. Predisposes horses to incisional herniation at later date. Tx: early recognition, bacterial culture, establish drainage, lavage wound if necessary, ? belly bandage. 

Term

 

Adhesions: 

Definition

 

Usually weeks after surgery fibrinous then fibrous adhesions may cause intestinal obstruction, strangulation etc recurrence of colic. Prevention = careful tissue handling, use of anti-adhesion therapy e.g. carboxymethylcellulose, heparin, seprafilm, peritoneal lavage. Tx = laparoscopic or open adhesiolysis if possible. 

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