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Colectomy
For removal of a portion of colon

Surgery of colon and rectum is done for various reasons including cancer, diverticulitis, inflammatory bowel disease, volvulus and fistulae.

Anatomy and Physiology

  • The large bowel absorbs 90% of the water content of the digested food it receives from the small intestine.
  • It also propels the residue towards the rectum, where it is stored and expelled with a bowel movement
  • The large bowel is composed of:
    1. Colon. The colon averages 150 cms. (60 inches) in length. The colon is divided into four segments: the ascending colon, transverse colon, descending colon and sigmoid colon. There are two bends (flexures) in the colon. The hepatic flexure is where the ascending colon joins the transverse colon. The splenic flexure is where the transverse colon merges into the descending colon. (Figure 1)
    2. Cecum. This is the first portion of the large bowel and is joined to the small bowel. The appendix lies at the lowest portion of the cecum. (see Appendectomy)
    3. The ascending colon is about eight inches in length, extends upwards from the cecum to the hepatic flexure near the liver
    4. The transverse colon is usually over 18 inches in length and extends across the upper abdomen to the splenic flexure
    5. The descending colon, usually less than 12 inches long extends from the splenic flexure downwards to the start of the pelvis
    6. The sigmoid colon, which is S-shaped and measures about 18 inches long. It extends from the descending colon to the rectum
  • Rectum. The rectum is a curved pouch that lies in the hollow formed by the sacrum and connects with the anal canal at its lower end.
  • The wall of the colon is composed of four layers (Figure 2):
    1. Mucosa - The epithelial (single layer of cells) lining is flat and regenerates itself every 3-8 days. Small glands lie beneath the surface
    2. Submucosa - The area between the mucosa and circular muscle layer and is separated from the mucosa by a thin layer of muscle, the muscularis mucosa
    3. Muscularis propria - The inner circular and outer longitudinal muscle layers
    4. Serosa - The outer single cell thick covering of the bowel. Similar to the peritoneum, the layer of cells that lines the abdomen
  • The colon does not have lymphatic channels in the submucosa between the mucosa and muscle. This is important because tumors invading into this area do not have lymphatic channels to metastasize (spread) through
Figure 1 - Anatomy of the colon. Figure 2 - Cross-section through the wall of the colon (see text). © C. Hogan

Pathology

  • Cancer of the colon and rectum is the most common cancer of the bowel. (Figure 3)
  • In men, it is the third most common lethal cancer next to cancer of the lung and prostate
  • In women, it is second only to lung and breast cancer as a cause of cancer related death
  • Cancer of the colon and rectum is common in patients over age 50 and steadily rises after that. Americans have about a five percent chance of developing colorectal cancer if they live to 70 years of age
  • The onset of familial and hereditary forms of colorectal cancer occurs at a much earlier age
  • Diverticulosis is a condition that is common in western society. It increases with age and is present in approximately 75% of Americans over the age of 80
    1. It is associated with diverticula, which are protrusions of the innermost lining of the colon through the muscular outer layers of the colon wall
    2. The diverticula can become inflamed, a condition called diverticulitis, which can cause perforation of the bowel abscess, bleeding, obstruction of the bowel or fistulae of the colon (a communicating hole between the colon and other organs such as the small bowel, urinary bladder, vagina or skin)
  • There may also be inflammatory bowel disease (called Crohn's disease}, ulcerative colitis or ischemic (decreased blood supply) colitis. These conditions result in inflammation of the colon that can involve the entire thickness of the colon wall (Crohn's disease, ischemic colitis) or only the mucosa, the innermost lining of the colon (ulcerative colitis)
Figure 3 - Colon cancer as seen through a colonoscope. The cancer completely surrounds the bowel wall leaving only a small lumen (opening). This cancer caused bowel obstruction.

History and Exam

Symptoms
that may not require surgery that may require surgery
rectal bleeding bleeding
abdominal pain perforation of the bowel wall
vomitingfistulae
 pain that is severe and persistent

Diagnostic Tests

  • Chemical testing of the stool for the presence of blood. The test is performed by placing a swab of stool on porous paper. A chemical is added that checks for the iron in red blood cells.
  • X-ray of the abdomen (flat plate). A simple X-ray of the abdomen may show pockets of fluid indicating problems with the colon.
  • Barium Enema. A solution of barium sulfate is given as an enema. The barium solution coats the inside of the bowel and any abnormality present. X-rays highlight the abnormalities.
  • CT of abdomen. A CT scan is obtained of the abdomen looking for a mass, fluid pocket or abnormal air/fluid level.
  • Colonoscopy/Sigmoidoscopy/Anoscopy. A short tubular instrument with a handle may be used to inspect the anus and adjacent rectum. A flexible tube attached to a fiber optic light source and television camera is passed into the rectum to the sigmoid colon (sigmoidoscopy). A longer flexible scope may be used to investigate the entire colon (colonoscopy). If a lesion such as a polyp is found, it may be biopsied or removed. (see Colonoscopy, Figure 4)
  • Virtual CT colonoscopy. This is a new technique. The patient is given a cathartic and enema to clear the bowel of feces. Air is used to inflate the bowel. A CT scan is then taken of the bowel. A special computer program then begins at the rectum and follows the inside of the bowel as it twists and turns. This technique may detect a lesion but a biopsy cannot be obtained. (Figure 5)
Figure 4 - Endoscopes used in the diagnosis of colon lesions. The anoscope is a short tubular instrument that examines the anus and rectum. The rigid sigmoidoscope can extend into the sigmoid colon while the flexible sigmoidoscope extends to the descending colon. The flexible colonoscope can be used to investigate the entire colon.
Figure 5 - Virtual CT colonoscopy demonstrating two polyps in the transverse colon.

Indications

  • Colectomy (removal of the colon) can be carried out for various diseases including:
    1. Cancer: Removal of the colon and rectum is the main stay of treatment for cancer. It can be curative or palliative at which time the surgery is performed to relieve symptoms. Colon surgery for cancer may be combined with other forms of treatment including radiotherapy and chemotherapy
    2. Polyps: Removal of the colon is performed for a condition called Familial Adenomatous Polyposis that is associated with numerous polyps in the colon at a young age. It carries a very high incidence of colon cancer and hence requires the removal of the entire colon to prevent malignancy
    3. Colitis: Colon resection may be performed in patients with inflammatory bowel disease (ulcerative colitis and Crohn's disease) with persistent, intractable pain and failure of medical treatment, intestinal obstruction, fistulae, bleeding, perforation, and marked dilatation of the colon
    4. Diverticular disease: Colon surgery is performed in patients with diverticulitis (acute inflammation of the diverticuli) with or without abscess formation, persistent profuse bleeding, or perforation of the bowel wall
    5. Other conditions that may necessitate removal of the colon include
      • Intestinal obstructions
      • Perforation of the colon wall
      • Volvulus in which the bowel is twisted on itself causing obstruction
      • Ischemic colon (lack of blood supply to the colon)
      • Toxic megacolon (massive dilatation of the colon)
      • Fistulae between the colon and other organs such as the bladder or vagina
  • Removal of the colon may be carried out as a scheduled procedure or as an emergency in life saving situations such as severe bleeding or perforation of colon
  • The extent of removal of the colon varies depending on the site of the disease. In the removal of the colon for cancer, all the lymph nodes that drain the tumor are also removed

Adjuvant Therapy (Complimentary Therapy)

  • Clinical trials are underway to determine the role of neoadjuvant therapy in treatment of carcinoma of the rectum
  • Neoadjuvant therapy for rectal tumors usually consists of external beam irradiation (X-ray radiation therapy) to the affected area plus administration of chemosensitizing agents (medication that enhances the effect of radiation)
  • Neoadjuvant therapy appears to result in a lower local recurrence rate following surgery. This downstages the tumor (shrinks the tumor mass) and more often allows preservation of the anal sphincters (muscles) in lower rectal tumors avoiding permanent colostomy
  • Neoadjuvant therapy appears to improve survival. A standard of care for these rectal lesions that includes neoadjuvant therapy should be forth coming in the next few years

Surgical Procedure

  • Before surgery, the bowel must be prepared to decrease the incidence of infection. Preparation begins a few days prior to colon surgery. The patient is placed on a low residue diet for 2-3 days prior to surgery and on liquids the day before surgery, with complete fasting from the midnight before surgery
  • The patient is usually admitted to the hospital on the day before surgery and is given some purgatives to cleanse the large bowel along with antibiotics
  • Intravenous fluids are given on the night before surgery to avoid dehydration resulting from the diarrhea due to the cleansing action of the purgatives
  • Intravenous antibiotics are usually administered just before surgery to reduce the incidence of infections. They may be continued after surgery.
  • The procedure is usually done under general anesthesia
  • An incision is made in the abdomen. The incision is carried through the wall of the abdomen to expose the bowel
  • The diseased portion of the colon is identified and that part of the colon and its blood supplied is divided and removed. The ends of the bowel are sutured together by hand with individual sutures. (Figure 6) Care is taken to identify the ureters, small intestine and other organs so as to avoid injury to these organs
  • In the last ten years, special instrumentation has greatly simplified the procedure. A stapler placed across the colon seals the colon on each side of the stapler and then cuts the colon between the staples. Likewise, a different type of stapler staples the anastomosis together. (Figure 7)
  • After surgery, the abdominal wound is usually closed although in cases with colon perforation, the wound may be left open and closed at a later date
Figure 6a - Left. Example showing removal of the left side of the colon. The tumor or other lesion is isolated with clamps and the bowel cut between the clamps. The bowel containing the tumor is removed. Figure 6b - Right. The two cut ends of the bowel are then joined together with sutures (anastomosis).
Figure 7a - Left. The tumor or other lesion is isolated by the use of a stapler that lays down two rows of staples across the colon and then cuts the colon between the staple rows. This is done both above and below the lesion (see dotted line and stapler). Figure 7b - Right. Stapler used for stapling the bowel together after laproscopic sigmoid colectomy. One part of the stapler is inserted into the colon above the sigmoid colon and pushed through the end (left). A suture gathers in the colon wall about the end of the stapler. The other end of the stapler is passed up though the rectum and through the staple line (center). The two parts are mated together (right) and the two parts of the stapler pushed together and stapled together. The wall is cut within the circular staples to complete the anastomosis and the stapler removed.
  • Sometimes, an emergency operation may need to be performed to remove the colon in cases with perforation of the colon, bleeding or diverticulitis
    1. In such cases, a colostomy is usually performed
    2. When a colostomy is performed the colon is brought out through a separate incision in the abdominal wall and sutured to the skin
    3. Feces are then excreted in to a bag attached to the skin
    4. This may be temporary or permanent
  • Tumors or lesions in the ascending colon can be treated by an operation to remove the last part of small bowel, the ascending colon, hepatic flexure, and a small part of transverse colon (right hemi-colectomy)
  • In a similar fashion, lesions of the descending colon and sigmoid are dealt with by left hemi-colectomy (removal of descending colon and adjoining parts of sigmoid colon, splenic flexure and part of transverse colon) and sigmoid colectomy respectively
  • After removal of a segment of colon, the two ends of the bowel are joined together (called an anastomosis). Tumors in the upper part of rectum and lower part of sigmoid colon are dealt with by an operation called an anterior resection, wherein the rectum and sigmoid colon are removed and lower end of the rectum is joined to the colon
  • Removing the entire rectum and part of the sigmoid colon (abdomino-perineal resection) is used in the treatment of tumors low in the rectum
    1. The end of the remaining colon is brought out as a colostomy
    2. Polyps or tumors that are very low in the anal canal can sometimes be resected from below, through the anus (transanal resection of the tumor)

Complications

In addition to the routine complications of any general anesthetic, there can be complications as a result of the colon surgery. These include:

  • postoperative bleeding
  • dehiscence or breakdown of the anastomosis
  • recurrence of tumor
  • wound infection
  • urinary or respiratory infections
  • deep vein thrombosis with or without pulmonary embolism
  • urinary retention
  • adhesions with bowel obstruction
  • injury to the ureter
  • obstruction at the anastomosis site

After Surgery

  • The recovery period after colon surgery is widely variable. It usually involves a stay in the hospital from 3-10 days in uncomplicated cases
  • The patient will have a catheter in the urinary bladder for a few days and will be given adequate pain relief, intravenous fluids, antibiotics etc
  • For patients who do not have any oral intake for several days, nutrition may be provided intravenously or through a tube in the stomach or bowel
  • The function of the bowel is monitored closely to await the passage of gas and stool after surgery
  • The patient then gradually begins to take liquids by mouth and solid food later on, following which they will be discharged home

After Care

  • The patient resumes normal activity in 1-3 weeks
  • Heavy exertion and lifting is avoided weights for 4-6 weeks
  • If a colostomy is required, the patient receives instruction on its care

Laparoscopic Colon Surgery

  • Because of recent advances in instrumentation, colon surgery can also be performed using the laparoscope
  • This method employs the use of a long tube containing a light and lens system for visualization and special instruments for manipulating the bowel through small incisions in the skin called ports
  • This surgery, however, is still in its development phase and is not widely done
  • Laparoscopic colon surgery can be performed for various elective indications of colon removal other than cancer
  • In cancer surgery, there have been instances of recurrence of tumor at the site of the laparoscopic ports. (There is, however, an ongoing study by the National Institutes of Health (NIH) to further evaluate the use of laparoscopic colon surgery for cancer.)
  • Stapling instruments similar to that used for routine colectomy have been developed for the laproscopic approach. (Figures 7)
  • Laparoscopic colon surgery enhances the prospect of speedy recovery of the patient as the incisions used are small and the patient experiences minimal postoperative pain. These patients may be discharged home earlier than routine open colon surgery