14. Basic surgical interventions. Anastomosis. Bypass.

Anastomosis

Written by Rhiana Devadasan

Anastomosis = a connection made surgically between 2 tubes/channels of the body (e.g. adjacent blood vessels, parts of the intestine, ducts, etc.), joint together using sutures, mechanical staplers and biological glues.

The 3 different types of Anastomoses:

1. End-to-end

2. End-to-side

3. Side-to-side

Examples of Anastomoses:

In the Digestive tract

• To reconnect bowel after resection (cutting out) of a segment or to bypass a diseased portion. (the reconnection involves the inverting of the bowel ends which are then united with a seromuscular stitch. Conventionally, the anastomosis is performed in four successive layers. The bowel ends are apposed and their back layers united with a continuous seromuscular suture of synthetic absorbable thread. It has been shown that single layer can be as safe as two layer anastomoses. The technique that can best be applied to all gastrointestinal anastomoses is a single layer of extramucosal interrupted sutures of synthetic absorbable thread, with edge-to-edge union)
• Colostomy (a surgical procedure used to divert one end or a loop of the large intestine out through the wall of the abdomen, through an opening called a stoma)

Vascular anastomosis

• The union of blood vessels (must be carried out by eversion in order to bring into apposition the inner endothelial layers. If this is not done, clots form at the anastomosis and block the lumen. Very small vessels can be united using very fine instruments and the procedure is performed using an operating microscope. It is not possible to evert the vessels; instead, the anastomosis is formed using a series of interrupted sutures bringing the ends together, edge-to-edge).
• Arteriovenous fistula (an opening created between an artery and vein) for dialysis
• A connection between a graft and a blood vessel to create a bypass

Can be reanastomosis to detached a previously anatomically anastomosis

• E.g. tubal reversal after tubal ligation

Complications:

1. Leakage

• Vascular leakage occurs earlier & leads to haemorrhagic shock
• Bowel leakage occurs later & leads to peritonitis

1. Bleeding

• -Needs attention to prevent formation of a large haematoma (with risk of subsequent abscess if contaminated).
• -The absence of bleeding at a bowel edge may indicate ischaemia.
• -A bowel anastomosis that looks cyanosed needs serious consideration for refashioning.
• -Urgent attention to persistent bleeding from an anastomotic edge is needed in vascular surgery.

1. Stenosis in bowel

May be due to: a fibrosis following a leak; inexpert technique; or recurrent tumour in a suture line.

1. Stenosis in arteries