Colectomy


Colectomy is the surgical removal of any extent of the colon, the longest portion of the large bowel. Colectomy may be performed for prophylactic, curative, or palliative reasons. Indications include cancer, infection, infarction, perforation, and impaired function of the colon. Colectomy may be performed open, laparoscopically, or robotically. Following removal of the bowel segment, the surgeon may restore continuity of the bowel or create a colostomy. Partial or subtotal colectomy refers to removing a portion of the colon, while total colectomy involves the removal of the entire colon. Complications of colectomy include anastomotic leak, bleeding, infection, and damage to surrounding structures.

Indications

Common indications for colectomy include:

Pre-operative preparation

Before surgery, patients typically undergo preoperative bloodwork, including a complete blood count and type and screen of blood type. Diagnostic imaging may include colonoscopy or CT scans of the abdomen and pelvis. In cancer patients, lesions are commonly tattooed via colonoscopy before colectomy to give the surgeon an intraoperative visual guide. For non-emergent procedures, patients are typically instructed to follow a clear liquid diet or fast and take a mechanical bowel preparation to clear the bowels before surgery. Antibiotics may also be prescribed ahead of surgery to reduce risk of post-operative infection.

Operation

Traditionally, colectomy is performed via an abdominal incision, a technique known as laparotomy. Minimally invasive colectomy using laparoscopy is a well-established procedure in many medical centers. Robot-assisted colectomy is growing in scope of indications and popularity.

Laparoscopic approach

As of 2012, more than 40% of colon resections in the United States are performed via a laparoscopic approach. For laparoscopic colectomy, the typical operative technique involves 4-5 separate incisions made in the abdomen. Trochars are introduced to gain access to the peritoneal cavity and serve as ports for the laparoscopic camera and other instruments. Studies have proven the feasibility of single port access colectomy, which would require only one small incision, but no clear benefit in terms of outcome or complication rate has been demonstrated.

Resection

Before removal, the portion of the bowel to be resected must be freed or mobilized. This is done by dissection and removal of the mesentery and other peritoneal attachments. Resection of any part of the colon entails mobilization and the cutting and sealing, or ligation, of the blood vessels supplying the portion of the colon to be removed. A stapler is typically used to cut across the colon to prevent spillage of intestinal contents into the peritoneal cavity. Colectomy as treatment for colorectal cancer also includes lymphadenectomy, or removal of surrounding lymph nodes, which may be done for staging of the cancer or removal of cancerous nodes. More extensive lymphadenectomy is sometimes accomplished by the removal of the mesocolon, the fatty tissue adjacent to the colon, which contains blood supply, lymphatics, and nerves to the colon.

Primary anastomosis vs colostomy

When the resection is complete, the surgeon has the option of reconnecting the bowel by stitching or stapling together the cut ends of the bowel or performing a colostomy to create a stoma, an opening of the bowel to the abdominal wall that provides an alternate exit for the contents of the gastrointestinal tract. When colectomy is performed as part of damage control surgery in life-threatening trauma resulting in destructive colon injury, the surgeon may opt to leave the cut ends of the bowel sealed and disconnected for a short time to allow for further resuscitation of the patient before returning to the operating room for definitive repair.
In modern times, surgical staplers are typically used to create colorectal anastomoses, although hand sewn, or sutured, anastomoses are still done today. Studies have shown that differences in rates of anastomotic leak and surgical site contamination for stapled vs. sutured anastomoses are not statistically significant. The increased speed and decreased human variability afforded by stapling make it an attractive option for most surgeons.
Several factors are taken into account when deciding between anastomosis or colostomy, including:
  • Urgency of presentation;
  • Contamination of the operative field;
  • Technical difficulty of the anastomosis;
  • Disease severity and stage;
  • Physiologic considerations: pelvic floor function, length of bowel remaining;
  • Patient factors: social support, socioeconomic status, level of education and health literacy, availability of specialist services, and level of functioning.
Giving a patient a colostomy avoids the risk of a failed anastomosis. Still, it places a societal, psychological, and physical burden on the patient, as a stoma requires special care and consideration.

Complications and risks

All surgery involves a risk of serious complications, including bleeding, infection, damage to surrounding structures, and death. Additional complications associated with colectomy include:
  • Damage to adjacent structures such as ureter, bowel, spleen, etc.;
  • Need for further operations;
  • Conversion of primary anastomosis to colostomy;
  • Anastomotic dehiscence or leak;
  • Inability to resect colon as intended;
  • Cardiopulmonary or other organ failure;
  • Death.
The overall risk depends significantly on the person's overall health. This type of surgery usually has high survival rates, but an emergency colonic resection performed on a frail elderly person with other health problems can have a significant chance of dying.

Anastomotic dehiscence and anastomotic leak

An anastomosis carries the risk of dehiscence or breakdown of the surgical connection. Contamination of the peritoneal cavity with fecal matter as a result of the anastomotic leak can lead to peritonitis, sepsis or death. In patients who underwent colectomy as a treatment for colorectal cancer, an anastomotic leak increases the risk of recurrence of cancer in the same area and reduces survival in the long term. Several factors influence the risk of anastomotic dehiscence, including preservation of blood supply to the cut ends of the bowel, tension on the anastomosis, and the patient's intestinal microbiome, which affects wound healing and potential for surgical site infection.
The use of NSAIDS for analgesia following gastrointestinal surgery remains controversial, given mixed evidence of an increased risk of leakage from any bowel anastomosis created. This risk may vary according to the class of NSAID prescribed.

Types

Right hemicolectomy and left hemicolectomy refer to the resection of the ascending colon and the descending colon, respectively. When middle colic vessels and transverse colon are also resected, it may be referred to as an extended hemicolectomy. Left hemicolectomy is most commonly indicated for cancer in the splenic flexure or descending colon, diverticular disease of the descending colon, and colovesicular or colovaginal fistulas that develop as a consequence of diverticular disease. The main limitation to performing a left extended colectomy is the difficulty of achieving a colorectal anastomosis afterward. Different techniques, such as Deloyer's or Rosi-Cahil's techniques, have been proposed to solve this issue. Right hemicolectomy is most commonly indicated for masses in the right, or ascending, colon but may also be performed for neoplasms of the cecum or appendix. Right-sided diverticulitis, cecal volvulus, inflammatory bowel disease, and adenomatous polyps are benign conditions that may require right hemicolectomy.
Transverse colectomy involves resection of the transverse colon, the segment of the colon between the hepatic flexure and the splenic flexure. Transverse colectomy is uncommon, as malignant pathologies of the transverse colon typically call for removal of the left colon or right colon as well as the transverse colon due to the variable contributions of the ileocolic, right colic, and left colic blood vessels to lymphatic drainage of the transverse colon. Transverse colectomy is sometimes appropriate for focal benign pathologies such as local inflammation and local trauma or injury such as perforation.
Sigmoidectomy is a resection of the last part of the colon, known as the sigmoid colon, and can include part or all of the rectum. Precancerous polyps and sigmoid colon cancer are common indications for sigmoidectomy. Benign indications for sigmoidectomy include diverticular disease, especially when complicated by perforation or fistulae, sigmoid volvulus, trauma, and ischemic or infectious colitis. When a sigmoidectomy is followed by terminal colostomy and closure of the rectal stump; it is called a Hartmann operation. This is usually done out of the impossibility of performing a "double-barrel" or Mikulicz colostomy, which is preferred because it makes "takedown" considerably easier.
When the entire colon is removed, this is called a total colectomy, also known as Lane's Operation. Total colectomy may be indicated as a prophylactic measure in certain hereditary polyposis syndromes such as familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer. Total colectomy is also performed for certain forms of inflammatory bowel disease, severe acute colitis, slow-transit constipation, and cancer. If the rectum is also removed, it is a total proctocolectomy. Sir William Arbuthnot-Lane was one of the early proponents of the usefulness of total colectomies and was considered a pioneer of colon surgery for routinely performing this procedure. However, his overuse of the procedure called the wisdom of the surgery into question.
Subtotal colectomy is resection of part of the colon or a resection of all of the colon without complete resection.