Principles of colonic surgery

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Colonic anastomosis

is more liable for : disruption , leakage & peritonitis because of the followings:

1-the highly infective aerobic &anaerobic organisms in the colon.2-constant gaseous distention.3-Incomplete serous coat.4-the terminal arteries poorly connect with each other.

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Preoperative preparation for colonic surgery

Patient counselingImproving nutritional statusBowel preparation

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In order to reduce the risk of leakage &wound sepsis:

The bowel must be empty at the time of operation

The bacterial flora of the colon is reducedIn elective cases the bowel is empty &clean ,so primary resection

(i.e. Resection &anastomosis at the same session)

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Mechanical preparation1- Standared prerarationnon-residue diet for 4 days before the operationenemas & mild laxatives 2-3 days before the operation2- rapid preparation: is an alternative that can be performed one day before surgery by one of the following methods: a- whole gut irrigation using 2-3 L/hour of a balanced crystalloid solution passed through a nasogastric tube until the patient passes clear fluid per rectum.(This method is not used in patients with cardiac ,renal diseases &in those with partially obstructed colon)

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b-Mannitol: one liter of flavoured Mannitol is given orally or by nasogastric tube. Metachlopromide may be administered to inhibit vomiting.

Chemical preparation:

intestinal antiseptics administered orally help to reduce the density of colonic bacteriaCombination of Neomycin & Metronidazole (Flagyl) for 2 days will cover the gram –ve bacilli and anaerobes which are normal residents in the large intestine

Prophylactic parenteral Antibiotics:

To minimize septic complication following colonic surgery ,systemic antibiotics are administered immediately before surgery & are continued for 1 day postoperatively ,this is termed ''perioperative antibiotic prophylaxis'‘ and is usually a combination of Cephalosporin or an aminoglycoside with either metronidazole or clindamycin .

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Operative Procedure

Resection:

The extent of resection is governed by the arterial blood supply &by the disease process

In radical surgery for malignant tumors ,it is essential to remove the draining lymphatics

Division of the peritoneal attachments allowsadequate mobilization of the bowel on its mesentery.

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Anastomosis:

For a successful anastomosis the two bowel ends should be adequatly vascularize and should be sutured without tensionAn intestinal anastomosis can be done in one of 2 methods:

Hand suturing is commonly done in 2 layers of interrupted sutures .The first layer induces the whole wall thickness .while the second incorporates the serosa and muscle only .to invert & seal the suture line .The defect in the mesentery is closed to prevent an internal hernia .

-Mechanical staplersare increasingly used ,They are faster but more coasty

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Emergency Surgery: In patients with obstruction ,,perforation ,toxic dilatation .or

massive bleeding from the colon →emergency surgery may be required.

In clinically ill obstructed cases ,a temporary Proximal colostomy to decompress the colon is done ,postponing resection to a later date.

If the patient's condition allows resection of the diseased colon should be carried out in the course of the emergency operation

�After exision of the diseased segment,• the surgeon is faced with a colon that is heavily loaded with

stools and bacteria ,the decision for further management depends on the site of the resected part .

• with right colon resection ,restoration of the bowel continuity by primary anastomosis is feasible. The ilium is anastomosed to the transverse colon (ilio-transverse anastomosis)

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With emergency excision of the other parts of the colon ,primary anastomosis is avoided because of the high possibility of disrupted suture line &leakage .The options are:

a-the proximal colon end is opened to the skin as a temporary colostomy .and the distal end is closed by sutures and replaced in the abdomen (Hartmann's procedure) ,both ends are opened to the skin ,the proximal one as a temporary colostomy ,

2.distal one as a mucous fistula ,

In either case,a second operation is needed to restore bowel continuity within few weeks

This second elective operation should be preceded by proper bowel preparation ..

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Intestinal stomas

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Intestinal stomas ileostomyIndications Proctocolectomy for ulcerative colitis or familial polyposis coli.Conventional ileostomy The stoma is fashioned so that a nipple of ileum protrudes from the skin, facilitating direct delivery of the irritant small bowel con tent into an appliance. Conventional ileostomosis are incontinent.Continent ileostomyA continent ileostomy may be done by fashioning a valve with an underlying reservoir (Kock pouch) which the patient regularly evacuates by passing a tube.ColostomyA colostomy is an opening of the colon to the skin.

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Colostomy13

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Permanent colostomy

1. After abdomino-perineal resection.

2. Irresectable carcinoma of the large bowel with obstruction.

3. Incurable cases of anal incontinence.

4. High anal fistulae that is not amenable to surgery.

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Types

1. Loop colostomy is usually temporary and is usu ally done in the right side of the transverse colon (transverse colostomy). This part is brought to the surface, fixed to the ab dominal wall, opened along one of the taeniae coli, and then stitched to the skin. A rod is passed beneath the loop to pre vent retraction, and is removed after one week.

2. End colostomy may be permanent or temporary. It is com monly constructed in the left or the sigmoid colon (iliac colos tomy) by bringing the divided end of the bowel to the surface.

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The lateral space between the exiting colon and the parietal peritoneum is closed to prevent an inter nal hernia. The colon is fixed to the abdominal wall muscles and is then stitched to the skin.

3. Caecostomy is occasionally used for temporary decompres sion of the colon but it is not as effective as the loop colostomy. Caecostomy is done by inserting a wide bore tube into the caecum.

Colostomy care A colostomy is an incontinent opening on the abdominal wall.• An iliac colostomy is easy to manage, as by time it functions

once or twice a day. The patient usually uses a colostomy ap pliance and evacuates its plastic bag when it is full .An alternative method is to wash out the colon through the colostomy once every morning. As the colostomy does not act during the rest of the day, a simple dressing is all that is neces sary.

• A transverse colostomy is wet, i.e., it discharges semi-liquid stools frequently, and, therefore, requires an appliance.

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Complications of colostomy The following complications can occur to any colostomy but are more

common after poor technique or siting of the stoma: prolapse; retraction; necrosis of the distal end; fistula formation; stenosis of the orifice; colostomy hernia; bleeding (usually from granulomas around the margin of the

colostomy); colostomy ‘diarrhea’: this is usually an infective enteritis and will respond

to oral metronidazole 200 mg three times daily.

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Many of these complications require revision of the colostomy.

Sometimes, this can be achieved with an incision immediately around the stoma but, on occasion, reopening the abdomen and freeing up the colostomy may be necessary. Occasionally, transfer to the opposite side of the abdomen may be necessary.

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