Common Colorectal Operations
Doctors and medical students should be familiar with these five common colorectal operations
Medical students and trainee doctors attached to my firm should make themselves familiar with the following five common major colorectal operations:
In this operation the right side of the colon is removed because it is diseased (red area in diagram). The caecum is always excised because this is the most expandable part of the colon and not a good area to anastomose to. Therefore the proximal resection margin is usually in the terminal ileum (see black line through ileum in diagram). The distal resection margin depends on the position of the disease process such as a colon carcinoma and can be in the ascending colon or anywhere in the transverse colon (see black line through ascending colon in diagram below). About 5cm of healthy bowel is resected distally to the colon pathology (see bold straight black lines either side of red pathology in diagram below). The terminal ileum has an excellent blood supply so the bowel is usually joined back together again and an ileocolic anastomosis is fashioned (X to X in the diagram below). This operation can be performed in the traditional open approach but patients often recover more quickly if the procedure is performed laparoscopically.
In this operation the left colon is removed because it is diseased by a condition such as tumour or diverticular disease (shown as red in diagram below). The proximal and distal resection margins (straight bold lines in diagram below) will depend on where the pathology is because we usually resect 5cm of healthy bowel either side of the lesion. The descending colon and sigmoid colon are usually removed. An anatomosis is always made (X to X in diagram below). The procedure can be carried out in the traditional open style via a large incision or in the more modern laparoscopic style via smaller incisions. Left hemicolectomy is becoming an old-fashioned term and many surgeons often now call this operation an anterior resection operation (see below).
It’s all in the words! In an anterior resection a part of the colon or rectum is removed via the anterior abdominal wall. The term used to be used exclusively for rectal resections but it is often now used for resections of the sigmoid colon and descending colon as well to simplify matters. Low rectal anterior resection operations can be much more technically challenging than high left colon operations so to help operation administrators know if an operation is likely to be longer or shorter than normal the terms ‘High anterior resection’ for descending and rectosigmoid colon lesions, ‘Low anterior resection’ for mid rectal lesions and ‘Ultralow anterior resection’ for low rectal lesions are often employed. In an anterior resection the proximal and distal resection margins depend on the position of the bowel lesion and normally 5cm of healthy bowel is taken either side of the lesion if possible (see bold straight lines in diagram below). In an anterior resection an anastomosis is always made (X to X in diagram below). However, the surgeon may sometimes want to give the bowel join a good rest especially if the anastomosis is in the low rectum. This is because the blood supply is not too good here which can compromise healing and it is thought that an anastomosis regularly passing stool through will likely require more energy and a greater blood supply than one that is not passing stool through. The surgeon can give the anastomosis a good rest by fashioning a defunctioning stoma such as a loop ileostomy. With a loop ileostomy all of the patients effluent escapes out of the ileostomy in to a stoma bag and the anastomosed bowel at the rectum does not have to work hard to move faecal material towards the anus. There is also the advantage that if the anastomosis develops a small leak then there is no stool around there to make the situation and likely infection worse and the body has time to heal and seal the small leak while the patient can still eat and drink and collect their stool in to an abdominal wall bag. The defunctioning stoma is usually temporary for a period of about three months. A contrast enema X-Ray will show if the anastomosis has healed nicely and if so a smaller operation can be conducted to reverse the ileostomy. Anterior resection operations can be conducted as open operations via a large midline abdominal incision or as laparoscopic operations via small keyhole incisions.
To recap an anterior resection operation always has an anastomosis made but the patient may be given a defunctioning stoma (usually a defunctioning loop ileostomy).
This operation was first described by Henri Hartmann, a French surgeon, in 1921. It is a common emergency operation and is used when the surgeon does not want to rejoin the bowel. Similarly to a left hemicolectomy or anterior resection, the pathology is in the descending or sigmoid colon or rectum (shown as red in diagram below). The pathology is excised but then in this case the surgeon decides that they do not want to make an anastomosis usually because there is peritoneal contamination or the patient is particularly sick and there is a risk that the blood supply to any anastomosis would be compromised and unsafe. Therefore the surgeon closes the distal resection margin (bold straight line at top of rectum below) leaving a rectal stump (see diagram below) and they bring out the proximal resection margin (upper bold straight line in diagram below) through the anterior abdominal wall to make an end colostomy (blue oval in diagram below). If the patient recovers from this operation then there is a possibilty that they can have their colostomy rejoined on to their rectal stump at a later date and this is called Reversal of Hartmann’s operation. Reversal of Hartmann’s procedure can be carried out in the open fashion via a large midline abdominal incision or in the modern laparoscopic fashion via small keyhole incisions.
To recap a Hartmann’s operation always has a rectal stump made and it always has an end colostomy formation.
Abdomino-Perineal (AP) Resection
It’s all in the words! In this operation the pathology is in the low rectum or anus. After the pathology is excised there is not enough distal rectum and anus to be anastomosed on to so the anus is excised completely (X in diagram below) and the proximal resection margin (bold straight line in diagram below) is brought out through the anterior abdominal wall to form a permanent end colostomy (blue oval in diagram below). This operation can be performed as an open operation by hand or by the keyhole laparoscopic approach which often has the advantage of a quicker recovery time and smaller scars. The surgeon first works through the abdomen to mobilise the left colon and rectum. Then they excise the anus via a perineal incision around the anus exit hole and the pathology specimen is usually pulled out through the perineal incision. This is therefore why the procedure is called abdomino-perineal resection or AP for short.
To recap an abdomino-perineal resection always involves the removal of the anus and the patient is always left with a permanent end colostomy.
Students should now draw five colon and rectum templates and see if they can draw the proximal and distal resection margins and any anastomoses or stomas for the above five common major colorectal operations.