Anastomosis is the medical term for a surgical connection between two tubular structures, channels, or passages that typically do not attach.

In medical terminology, anastomosis is when surgeons connect two tube-like structures inside the body.

People may need anastomosis to join blood vessels or sections of the bowel.

This article looks at the types of anastomosis and their uses. It also outlines what to expect during and after anastomosis.

surgeons in a theatre doing a procedure involving anastomosisShare on Pinterest
Surgeons may perform anastomosis to repair damage to veins or arteries.

The term “anastomosis” refers to a connection between two tubes or passages that would usually branch away from each other.

Anastomosis in biology

Anastomosis occurs naturally in the body, where veins and arteries connect to transport blood around the body.

In the vascular system, it creates a backup pathway for blood flow if something blocks a blood vessel.

Vascular fistulae are abnormal anastomoses, where blood vessels join together through injury, inflammation, or disease.

Anastomosis in medicine

In surgery, an anastomosis occurs when a healthcare professional connects two tube-like structures in the body.

Examples of these structures include:

  • two blood vessels
  • two sections of bowel
  • two parts of the genitourinary tract

People may require anastomosis to:

  • repair damage to veins or arteries
  • create a bypass for blocked arteries
  • connect a donor organ to a blood supply
  • rejoin two sections of the intestine after the removal of damaged or diseased tissue

Conditions that may require anastomosis

Anastomosis can also be used to treat the following conditions:

Intestinal blockages

An intestinal blockage is an obstruction in the bowel. Blockages in the small intestine can come from scar tissue, hernias, or small bowel tumors. Large intestine obstructions are usually from cancer but may also result from other conditions, such as volvulus, when the intestine twists.

Doctors may perform a bowel resection to treat an intestinal blockage. A resection removes the part of the intestine with the blockage. As part of this procedure, surgeons reattach parts of the bowel using anastomosis.

Ulcerative colitis

Ulcerative colitis (UC) is a chronic condition that causes ulcers and inflammation in the large intestine. A doctor may recommend surgery to remove the rectum and colon if a person has UC complications, such as severe rectal bleeding.

Surgery options for UC are ileostomy and ileal pouch-anal anastomosis (IPAA). During an IPAA, or “J-Pouch” procedure, a surgeon removes the colon and rectum. The surgeon turns the end of the small intestine (ileum) into a pouch and connects it to the top of the anal canal using anastomosis.

Crohn’s disease

Crohn’s disease is a chronic inflammatory condition that causes irritation of the digestive tract. Doctors may recommend surgery to treat complications such as severe bleeding, fistulas, and bowel obstructions.

A person may have small bowel resection or large bowel resection to treat Crohn’s disease. In these procedures, anastomosis reconnects the parts of the bowel after a surgeon has removed sections.

Colon polyps

Colon polyps are growths inside the inner lining of the large intestine. They are rarely cancerous, but doctors remove and test them just in case. Most polyps are taken out using a wire loop during a colonoscopy.

If there are many polyps or they are very large, a doctor will remove them by cutting out part of the intestine. This procedure is known as a bowel resection. The surgeon reconnects parts of the intestine using anastomosis.

Colon cancer

Colorectal cancer describes co-occurring colon cancer and rectal cancer. Cancerous cells in these organs can quickly spread if a person does not receive treatment. Surgery is the main treatment for colorectal cancers.

The type of surgery depends on the location of the cancer.

A low anterior resection removes the part of the rectum that contains cancer. A surgeon connects the colon to the remaining rectum using anastomosis. During a proctectomy, the surgeon removes the entire rectum. A coloanal anastomosis then connects the colon to the anus.

Colectomy is another type of colon cancer surgery. A surgeon removes all or part of the colon and reconnects the intestine with anastomosis.

Traumatic injury

A person may have an injury to the bowel after a traumatic event, such as a motor vehicle accident. When a person has a blunt or penetrating bowel injury, there are different surgical options. One is to reconnect parts of the bowel by creating an anastomosis.

There are two main types of anastomosis: Bowel anastomosis and vascular anastomosis.

Bowel anastomosis

Bowel anastomosis connects two sections of the bowel or connects the bowel to other structures within the body. The different types of bowel anastomosis include:

  • Intestinal anastomosis: This involves removing part of the colon and joining the two remaining sections.
  • Ileocolic or ileocolonic anastomosis: This connects the end of the small intestine to the colon, usually after a bowel resection.
  • Colectomy: A colectomy involves removing the colon and attaching the end of the small intestine to the rectum.
  • Single anastomosis gastric bypass (SAGB): People may have a gastric bypass to aid weight loss. A SAGB procedure involves turning part of the stomach into a gastric pouch and attaching it to a small loop of intestine. This restricts a person’s food intake and reduces calorie absorption.
  • Hepaticojejunostomy: This involves connecting a hepatic duct to a section of the small bowel, permitting digestion of food following certain pathological processes that harm the bile ducts, pancreas, or the duodenum.

Vascular anastomosis

Vascular anastomosis connects blood vessels. There are three types:

  • arterioarterial anastomosis, which connects two arteries
  • venovenous anastomosis, which connects two veins
  • arteriovenous anastomosis, which connects an artery to a vein

This procedure can create durable dialysis access for people with kidney failure.

Surgeons often use staples or stitches when connecting tissues during an anastomosis.

Stapling is the more common method for most bowel anastomoses because it is quicker than sewing and offers consistency in the quality of the intact seal between the joined structures.

Depending on the type of anastomosis procedure that a doctor plans, the person may receive a general anesthetic or a local anesthetic.

The type of anastomosis a person has depends on their underlying condition.

The surgeon will carry out the anastomosis during one of the following procedures:

  • Laparoscopy, or “keyhole surgery”: This is a minimally invasive procedure that involves inserting a laparoscope into a small incision in the abdomen. A laparoscope is a thin, flexible tube that has a light and camera at one end. The instrument allows the surgeon to see inside the abdomen while operating.
  • Open surgery, or “laparotomy”: This procedure involves making a larger incision across the abdomen.
  • Hand-assisted laparoscopy: The surgeon makes an incision large enough to insert a hand to manipulate tissue. The procedure creates a smaller incision than is necessary for conventional open surgery but is more invasive than a laparoscopy.
  • Robotic surgery, or “robot-assisted laparoscopy”: This is minimally invasive and similar to laparoscopy, but the surgeon uses a console to control a surgical robot. The chief advantage is that the system allows the surgeon more dexterity and 3D vision of the structures inside the body.

The recovery time from surgery that involves anastomosis will depend on several factors, including:

  • the medical reason for the surgery
  • the type of technique the surgeon used
  • whether the person had any other health issues

People who have laparoscopic or robotic surgery typically experience a shorter recovery time than those who have open surgery. Both minimally invasive methods may also be less painful and result in less scarring.

A person can expect to feel weak or tired for 2–3 months after bowel surgery. People should follow their doctor’s instructions to ensure they heal effectively and minimize the risk of complications.

The following may help the healing process:

  • eating small, frequent meals and reducing fiber if a person has bloating or flatulence
  • resting when necessary, but also doing moderate exercise such as walking
  • not lifting anything heavy
  • following the doctor’s advice for wound care at home
  • taking any medications as the doctor prescribes

A potential complication of any anastomosis is leakage.

Anastomotic leakage is when the anastomosis does not heal correctly, causing internal fluid to leak out. This is a serious condition that requires immediate medical treatment.

Risk factors and symptoms

Researchers do not know the causes of anastomotic leakage. However, the following may increase a person’s risk:

  • malnutrition
  • existing health problems
  • poor wound healing due to smoking or diabetes
  • long operation time
  • previous abdominal surgery
  • emergency surgery
  • older age
  • being male
  • technical challenges

Symptoms of an anastomotic leak include:


Doctors may use the following to diagnose an anastomotic leak affecting the intestinal tract:

  • CT scan: A CT scan combines a series of X-rays to produce a detailed picture of the inside of the body. However, CT scans may be less effective at detecting leakage than other methods.
  • Contrast enema: A person receives an enema containing a contrast agent such as iodine or barium. The agent provides a detailed image of the colon during X-ray.
  • Endoscopy: During an endoscopy, a doctor inserts a thin, flexible tube, or endoscope, into the abdomen via the rectum. The endoscope has a light and camera to allow the doctor to see inside the abdomen.
  • Repeat surgery (exploration): A doctor may perform another surgery to examine the area.

Anastomotic leakage can be life threatening and requires immediate medical treatment.

In medicine, an anastomosis is when surgeons join two tube-like structures or passageways in the body. There are two main types of anastomosis: Bowel and vascular.

Recovery from an anastomosis may take several weeks. During this time, a person will need to follow their doctor’s instructions for wound care to ensure proper healing.

In some cases, people may experience complications of anastomosis. Anyone who experiences symptoms of anastomotic leakage should seek immediate medical treatment.