The most common indication for fashioning a colostomy is cancer of the rectum. Since a colostomy is an opening of the large intestine with no sphincteric control, its location would obviously be better on the abdominal wall than in the perineum, where an appliance cannot be maintained. A distal colorectal anastomosis in an elderly patient with a poorly functioning anal sphincter may result in what is essentially a “perineal colostomy.” In these cases, it often behooves the surgeon to construct a good colostomy rather than to restore intestinal continuity to an incontinent anus. Colostomies are also constructed as treatment for obstructing lesions of the distal large intestine and for actual or potential perforations.
Type by Anatomic Location
Traditionally, the type of colostomy has been categorized by the part of the colon used in its construction. The most common type has been called an “end-sigmoid” colostomy. However, if the origin of the inferior mesenteric artery is transected during an operation for cancer of the rectum, the blood supply to the sigmoid colon is no longer dependable, and it should not be used for stoma construction. Therefore, an “end-descending” colostomy is usually preferable to an end-sigmoid colostomy. Other types of colonic stomas include the transverse colostomy and cecostomy. The physiology of the colon should be taken into account when considering stoma construction. The right side of the colon absorbs water and has irregular peristaltic contractions. Stomas made from the proximal half of the colon usually expel a liquid content. The left colon serves as a conduit and reservoir and has a few mass peristaltic motions per day. The content is more solid, and in many cases the stoma output can be regulated by irrigation. Proximal colostomies should be avoided, as they will combine the worst features of both a colostomy and an ileostomy: liquid, high-volume, foul-smelling effluent. The left colon should be used for a colostomy if possible; the distal transverse colon is also a reasonable choice.
Determination of Colostomy Location
The location of the colostomy must be carefully selected preoperatively. It should avoid any deep folds of fat, scars, and bony prominences of the abdominal wall. The site is chosen by evaluating the patient in the standing, sitting, and supine positions. Often abdominal skin and fat folds are only noted with the patient in the sitting position. A stoma faceplate is applied to the abdominal wall with its medial margin at the midline; care is taken to not overlay any fold, scar, or prominence; and the stoma site is marked. The inguinal fold and waistline fold should be avoided. If a sigmoid or descending colostomy is contemplated, the most desirable position is usually in the left lower quadrant of the abdomen. However, if the patient is obese, it may be preferable to site the colostomy in the left upper quadrant so that it is visible to the patient and not trapped on the undersurface of a panniculus. If a distal transverse colostomy is planned, the left upper quadrant is usually the preferable site. Please refer to the section on determination of the ileostomy location for more details regarding stoma site selection.
More important than the anatomy of the colon is the function that the colostomy is intended to perform. There are two considerations: (1) to provide decompression of the large intestine, and (2) to provide diversion of the feces.
A decompressing colostomy is most often constructed for distal obstructing lesions causing dilation of the proximal colon without ischemic necrosis, severe sigmoid diverticulitis with phlegmon, and for select patients with toxic megacolon. Alternative treatments exist for these conditions: total abdominal colectomy with ileostomy or ileorectal anastomosis; segmental colectomy with construction of end colostomy; segmental colectomy with primary anastomosis; and segmental colectomy with intraoperative colonic lavage and primary anastomosis with temporary diverting loop ileostomy. However, temporary decompressing stomas are still useful and safe. The procedure acts as a bridge to definitive operation for toxic patients with benign disease and those with malignant distal obstruction. The disadvantages of a decompressing stoma is that it does not provide definitive management of the disease process and thus the patient often requires subsequent operation, and it does not necessarily provide complete fecal diversion and thus carries the risk of potentially fatal sepsis if there is distal perforation.
Types of Decompressing Stomas.
There are three types of decompressing colostomies: (1) the so-called “blow-hole” decompressing colostomy constructed in the cecum or transverse colon, (2) tube cecostomy, and (3) loop colostomy.
Cecostomy and “Blow-Hole” Colostomy.
A cecostomy should be constructed only rarely because it is difficult to manage postoperatively. It should be reserved for the severely, acutely ill patient with massive distention and impending perforation of the colon. This is seen most often with distal obstructing cancer or in some of the pseudo-obstruction syndromes seen in elderly or immuno-compromised patients. Because these operations are done on an urgent basis and the abdomen is usually distorted by intestinal dilation, the choice of site for an incision is over the dilated cecum. The location of this incision or of an intended decompressing transverse colostomy can be selected by placing a marker on the umbilicus when an abdominal film is obtained.
The construction of a blow-hole cecostomy or transverse colostomy (Fig. 9-1) is carried out by making a 4–6 cm transverse incision over the most dilated part of intestine and then placing a series of interrupted, seromuscular, absorbable sutures between the peritoneum and the seromuscular layer of the bowel to be decompressed. This should be done through an incision sufficient to allow subsequent incision of the intestine and suturing of the intestine to the skin. The bowel wall will be very thin, and it is not unusual to have leakage of gas as the sutures are being placed. A disadvantage of a cecostomy or loop colostomy done through a small incision is that one cannot evaluate other parts of the colon for potential ischemic necrosis due to massive dilation.
Construction of blow-hole cecostomy or colostomy. A. The incision is located over the most dilated aspect of the intestine. B. After the peritoneum is quarantined, gas is allowed to escape, decompressing the bowel. C. Placement of the quarantine sutures. D. The colon is opened, and more adequate aspiration is effected. E. Details of the second level of quarantine sutures between the fascia and seromuscular layer of the colonic wall (this should be completed before the bowel is opened). F, G. The stoma is completed by placement of sutures between skin and colonic wall. H. Completed blow-hole stoma.
Once the first layer of sutures has been placed and the intestine is sealed from the remainder of the abdominal cavity, needle decompression of the gas-distended viscus is performed to reduce the tension on the intestinal wall. When this procedure is completed, a second layer of absorbable sutures is placed between the seromuscular layer of the intestine and the fascia of the abdominal wall. Subsequently, the colon is incised, usually with release of a large amount of liquid and gas. The full thickness of intestine then is sutured to the full thickness of skin, again with absorbable sutures, and an appliance is placed over the stoma. Postoperatively, it is not unusual for there to be significant inflammation in the abdominal wall around such a stoma, and after a period of weeks, significant prolapse may occur. Therefore, these stomas should be used for short periods of time, with definitive resection performed as soon as possible.
A tube cecostomy (Fig. 9-2) is constructed by making an incision similar to that used for a “blow hole” colostomy, by formal laparotomy, or by laparoscopy. A purse-string suture is placed in the cecal wall, and a large mushroom-tipped or Malecot catheter is placed in the cecum. The purse-string suture secures the catheter. Usually a second purse-string suture is placed, and the tube is brought through a right lower quadrant incision. The cecum then is sutured to the peritoneum of the abdominal wall. The advantage of this stoma is that there is less chance of prolapse. The major disadvantage is that the tubes usually become blocked with feces, drain poorly, and sometimes leak stool adjacent to the drain. Because of all their disadvantages, tube cecostomy and blowhole colostomies are rarely performed at present.
Construction of a tube cecostomy. A. The cecostomy is constructed over the most dilated aspect of the cecum. B. A very large Malecot or mushroom-tipped catheter is used. C, D. The catheter is secured within the cecum by two purse-string sutures. E. The cecum is sutured to the abdominal wall at the entry site of the catheter. F. Cross section of the completed tube cecostomy.
A loop colostomy using the transverse colon (Fig. 9-3) or left colon can be used as a decompressive stoma, although it will usually completely divert the flow of stool away from the distal colon and can thus be considered a diverting stoma. Occasionally, the posterior wall of the stoma recesses far enough below the wall of the abdomen so that stool can enter the distal loop, although this is uncommon. These stomas are constructed for reasons similar to those described for the blow-hole type stoma and to provide temporary diversion for protection of complicated distal anastomoses. The other advantage is that when properly constructed, a loop colostomy can serve as a long-term stoma. The incidence of prolapse is not prohibitive. Parastomal hernias can occur if the fascia is not closed tightly enough, and these stomas usually cannot be regulated by irrigation techniques.
The site can be chosen for this stoma in an emergency situation as previously described, but it should be marked electively on the abdominal wall in preparation for potential construction in patients who are to have low colorectal anastomoses or in those in whom it is anticipated that an inflammatory reaction will be encountered and will require temporary diversion of intestinal contents as a safeguard against contamination from a leaking anastomosis. This occurs occasionally in patients with severe diverticulitis. In an elective situation, the stoma can be placed through the rectus muscle either on the right or left side, depending on later intentions of closing or resecting the colostomy site in continuity with a cancer operation, or it can be brought through the midline (Fig. 9-3A). If performed in conjunction with a midline incision, a midline colostomy site may be suboptimal because of difficulty with placing the ostomy appliance over the fresh incision.
Construction of a loop-transverse colostomy. A. Choice of stomal location. B, C. Tracheostomy tape is used to pull the loop of colon through the incision. D. The fascia is closed tightly around the loop of intestine. E, F, G. The loop of colon is opened over a supporting rod and is sutured to the skin of the abdominal wall.
Construction of loop colostomy requires the colon to be mobile enough to be brought to the level of the abdominal wall (Fig. 9-3B). If this cannot be done or if the colon is so massively dilated that loop colostomy is not safe, one should resort to the use of a blow-hole colostomy as previously described, in which only one wall of the intestine is utilized and tension on the mesentery is avoided. A transverse loop colostomy can be constructed by placing a tracheostomy tape or soft latex drain around the colon at the site chosen for the colostomy. The transverse colon at this site is usually dissected free of the overlying omentum in the embryonic peritoneal fusion planes. The tracheostomy tape and colon are brought through an avascular window in the omentum to allow better sealing between the colon and the abdominal wall (Figs. 9-3B and 9-3C). The fascia is then closed on either side of the loop of colon tightly enough to allow snug passage of one fingertip (Fig. 9-3D).
The skin is then snugly closed, on either side of the loop of colon. The tracheostomy tape is replaced by a plastic rod that frequently has a suture through each end so that it can be easily repositioned should it be displaced (Fig. 9-3E). The wound is protected, and attention is directed to the protruding loop of colon, which is incised either longitudinally or transversely to allow the best separation of the edges of the colon (Fig. 9-3F). Full thickness of intestine is then sutured to full thickness of skin with absorbable suture material (Fig. 9-3G). If this stoma is properly constructed, the posterior wall will bulge upward, providing the desired diversion as well as decompression. An appliance is applied either over the rod or beneath the rod, depending on the tension of the stoma.
If there is a possibility that the colostomy may become permanent, it may be advantageous to divide the colon with a stapler and create a “divided end-loop” stoma in the manner of Prasad and Abcarian. The proximal colon is matured as an end colostomy, and a corner of the distal limb opened and matured as a mucus fistula in the same stoma incision to vent the distal colon (see Fig. 9-9, construction of separated [divided end-loop] ileostomy). The stoma size is typically smaller than a loop colostomy and the tendencies to prolapse or retract may be lessened.
In the postoperative period, the appliance is emptied or changed as necessary, and the wound is kept clean. The rod is usually left in place for several days and then is easily removed. The colostomy appliance is fashioned as necessary as the contour of the stoma and skin opening change. Patients with this type of stoma usually are not taught to irrigate, because irrigation is infrequently successful. After the immediate postoperative period, the patient usually is instructed to empty the appliance as necessary and to change the entire appliance every 3 to 4 days, depending on the condition of the skin and the ability to maintain an adequate seal of the appliance to the skin.
Closure of a Temporary Colostomy.
The most important consideration in dealing with closure of a temporary colostomy is deciding when it is safe to restore intestinal continuity. Distal integrity and adequacy of sphincter muscle function must be carefully evaluated before closure of the stoma is undertaken. The reason for constructing the stoma initially must be taken into account, and contrast studies and endoscopy should demonstrate clearly that the original reason for fecal diversion no longer exists.
Adequate function of the anal sphincter must be demonstrated before the temporary colostomy is closed. This can be done by formal manometric and electromyographic studies or by giving the patient a 500-mL enema and asking him or her to hold it until he or she can comfortably walk to a toilet and expel the enema. If the sphincter does not work and cannot be repaired, the patient will be better off with a properly constructed end colostomy than with attempts to preserve a nonfunctional sphincter. Once it is decided that it is safe to close the colostomy, the procedure should be undertaken with the same skill and precaution as that required for a colon anastomosis (Fig. 9-4). The complication rate following colostomy closure is not insignificant, and is cited by some authors as a reason to avoid diverting colostomy construction at all costs. However, as with all issues in medicine, careful consideration of the potential risks and benefits of the procedure in the individual patient should be made prior to deciding on whether or not fecal diversion is indicated.
Closure of a loop-transverse colostomy. A. A circumferential incision is made around the stoma, with reopening of the midline incision if needed. B, C. The colon is mobilized adequately. D, E. Staple closure of the colostomy. F, G. Suture closure of the colostomy.
The closure is begun by making a circumferential incision around the stoma, including a small rim of skin (Fig. 9-4A). If the stoma has been placed in the midline, the midline incision may be opened on either side of it to allow adequate mobilization. The circumferential incision is deepened until the peritoneal cavity is entered and the colon and surrounding omentum can be separated from the abdominal wall. The colon is then brought through the incision, and the serosal surface is clearly defined circumferentially (Figs. 9-4B and 9-4C). This involves resecting omentum and fibrofatty tissue from the serosal surface. Once this step is completed, the stoma is ready for closure, which can be accomplished by a linear stapling device (Figs. 9-4D and 9-4E), by a hand-sutured closure (Figs. 9-4F and 9-4G), or if the bowel has been compromised in any way, by complete transection of the colon and construction of a formal end-to-end anastomosis. Caution must be taken to ensure that no small intestine has been injured and that no significant bleeding has been left unattended. Once this has been accomplished, the colon is returned to the abdominal cavity and the abdomen is closed. Usually the skin itself is left open for delayed primary closure.
A diverting colostomy is constructed to provide diversion of intestinal content. It is performed because the distal segment of bowel has been completely resected (as during abdominoperineal resection), because of known or suspected perforation or obstruction of the distal bowel (eg, obstructing carcinoma, diverticulitis, leaking anastomosis, or trauma), or because of destruction or infection of the distal colon, rectum, or anus (eg, Crohn's disease or failed anal sphincter reconstruction).
Choices for Construction.
Although a completely diverting colostomy can be made only by complete transection of the colon, a well-constructed loop-transverse or sigmoid colostomy may provide near complete fecal diversion. Stool and flatus will move preferentially toward the low-pressure side of any pressure gradient, and this usually means that it will flow into the stoma appliance, which is at atmospheric pressure, rather than into the distal bowel. However, patients who have loop stomas must be counseled that if the stoma appliance becomes full, stool and flatus can be forced distally because the pressure gradient now favors passage of intestinal contents into the distal limb of intestine. This discussion should take place prior to discharge from the hospital, as this phenomenon usually occurs late at night after the patient has slept and not emptied their appliance. The first passage of flatus or stool per anus in a patient who was under the impression that their fecal stream was completely diverted can be sufficiently alarming as to prompt an emergent call to the surgeon, usually in the wee hours of the morning.
There are some situations in which the diverting loop colostomy fails to divert the flow of stool because the stoma retracts into the abdomen and stool flows into the distal colon. Patients who are profoundly malnourished may be at increased risk of this complication. In addition, stomas that are constructed under tension may also be prone to retraction.
If a colostomy is being performed proximal to an obstructing lesion, to decompress the colon and divert the flow of stool, it is critical that the distal limb of the colostomy be vented to the atmosphere and not closed. If the distal limb is closed and there is a complete obstruction distal to the colostomy, this will create a closed loop obstruction, and there is a substantial risk of distention and perforation.
If the rectum and anus have been completely resected, an end colostomy is created. If a partial colectomy/proctectomy has been performed, and an anastomosis is not constructed, an end colostomy is created and the distal bowel is closed (as in a Hartmann resection) or brought to the skin as a mucus fistula. The decision about whether to create a mucus fistula or to close the distal segment will hinge on whether there is concern regarding distal obstruction, the length of the distal segment, and the integrity of the distal segment. For example, in a patient undergoing sigmoid colectomy and colostomy for complicated diverticulitis, it is reasonable to close the rectal stump providing that proctoscopy reveals a normal rectum. Conversely, in a patient undergoing abdominal colectomy and ileostomy for toxic colitis, it may be preferable to bring the distal sigmoid to the skin level as a mucus fistula to avoid rectal stump blowout. A mucus fistula may be constructed as a separate stoma, opening just a corner of the closed end as a small vent. Alternatively, the mucus fistula can be constructed so that the small vent is matured (“mature” means that the colonic wall is sutured primarily to the skin) in a corner of the abdominal wall opening used to create the proximal stoma in the manner of Prasad and Abcarian (the “divided end-loop” stoma). This facilitates care in that the patient has only one stoma appliance, and facilitates stoma closure because both limbs of the bowel are located adjacent to one another. The old operation of the so-called Divine double-barreled colostomy should be abandoned because the adjacent full-diameter stomas make application of an appliance very difficult.
Construction of an End Colostomy (Fig. 9-5).
An end, completely diverting, colostomy usually is located in the left lower quadrant, where the site is chosen preoperatively by placing a vertical line through the umbilicus and another line transversely through the inferior margin of the umbilicus and by affixing a disk, the size of a stoma faceplate to designate the stoma opening through the rectus muscle and on the summit of the infraumbilical fan fold (Fig. 9-5A).
Construction of an end (diverting) colostomy. A. Selection of stoma location and technique of incision of the abdominal wall at the colostomy site. B. Technique of colonic mobilization and provision of adequate blood supply for the colostomy. C, D, E. Final stages of constructing a “mature” end colostomy. (LC, left colic artery; MC, middle colic artery; ALC, ascending left colic artery; DLC, descending left colic artery.)
Once a site is chosen, the patient should be evaluated in multiple body configurations to verify the adequacy of the stoma site. A common mistake is to choose the site with the patient supine and then find when the patient rises to a standing or sitting position that the chosen site is completely obscured by fat folds, scar tissue, or a protruding skeletal structure. The location should be adjusted up or down, even considering the use of upper quadrants of the abdomen if necessary, to allow proper fixation of an appliance and easy access by the patient. The site usually is marked with ink in the patient's room and then is scratched into the skin with a needle in the operating room after induction of anesthesia. This is totally painless for the patient and does not leave a permanent tattoo should colostomy not be needed.
An end colostomy most often is constructed after removal of the rectum for low-lying malignancy (see Chap. 40). The entire left colon is mobilized on its mesentery, and depending on mobility of the colon and thickness of the abdominal wall, may require mobilization of the splenic flexure (Fig. 9-5B). If the patient has received neoadjuvant pelvic radiotherapy and/or the inferior mesenteric artery is transected at its origin at the aorta, the entire sigmoid colon should be removed because of concerns regarding ischemia and a descending colostomy created.
If the colostomy is to be brought through the left lower quadrant, an opening in the abdominal wall is made at the previously marked site by excising a 3 cm disk of skin. The undesirable oval configuration of a stoma is avoided by placing traction clamps in the dermis, the fascia, and the peritoneum. These clamps are held in alignment when the opening is made through the abdominal wall. This duplicates the configuration of the abdominal wall when the abdomen is closed and should allow construction of a desirable circular stoma.
The fat, fascia, muscle, and posterior peritoneum are incised longitudinally (Fig. 9-5A). The opening is then dilated, and the closed end of the colon is pulled through the abdominal wall (Fig. 9-5C). The mesentery of the colon can be sutured to the lateral abdominal wall with a running suture, although the complication of small bowel obstruction due to torsion of the small bowel mesentery around the colon mesentery has not been proven to be reduced by this maneuver. After the wound is closed and protected, attention is directed to completing the colostomy (Figs. 9-5C, 9-5D, and 9-5E). The stoma is completed by excising the staple or suture line and by placing chromic catgut sutures between the full thickness of colon and skin. If the stoma is constructed because of inflammatory bowel disease or radiated bowel, a spigot configuration is utilized by applying principles similar to those for ileostomy construction. This facilitates a good appliance seal for anticipated high-volume, liquid effluents.
Once the stoma construction is complete, an appliance is applied in the operating room. The simplest is a one-piece appliance with a skin barrier that can be cut to the appropriate size of the stoma. This same appliance can be used for colostomy and ileostomy. The appliance, which need not be sterile, is held in place with the skin adhesive of the appliance. Tincture of benzoin or other similar adhesives should never be used to maintain adhesion of an appliance to the skin because it has a high risk of initiating contact dermatitis. If colostomy function does not begin within 4 or 5 days, the stoma can be irrigated with small volumes (250 mL) of normal saline to initiate stoma function. The stoma nurses are involved early in the care of the stoma and in teaching the patient and family to provide long-term care of the colostomy. In some cases, the patient is taught the technique of stoma irrigation, and then each individual decides in the more distant postoperative course if she or he wishes to irrigate the stoma or not.
Long-Term Colostomy Management
The patient with a properly constructed, well-functioning colostomy may elect to irrigate once a day or every other day and to wear only minimal appliance over the stoma or simply cover it with a gauze in the intervening period, although the patient should be instructed to always carry an appliance should episodes of diarrhea occur. Simple appliances exist to allow absorption of mucus and deodorized passage of gas during the period between irrigations, if the patient elects to irrigate.
The advantages of irrigating the colostomy include the absence of need for wearing an appliance at all times, the provision of a more regulated lifestyle, the reduced passage of uncontrolled gas, less leakage of stool between irrigations, and the general feeling of comfort that some people experience after irrigating the colostomy. The disadvantages are that it is a time-consuming ritual and that some people feel discomfort when the bowel is distended during irrigation. Irrigation carries a minimal risk of perforation. Absorption of water during the irrigation process can be significant, and the patient with an irritable bowel syndrome will usually not achieve adequate control by irrigation and may be frustrated by attempting to do so. The principle of irrigation is based on the fact that the distal colon displays a few mass peristaltic motions each day and that these can be stimulated by distention of the intestine. It has been shown that 80% of people who irrigate daily can depend on the discharge from the colostomy being one or two movements per day. Poor results from irrigation can be anticipated if the patient has irritable bowel syndrome, a peristomal hernia, irradiated bowel, inflammatory bowel disease, poor eyesight, reduced manual dexterity, or simply fear of dealing with the intestine at the abdominal wall. A preoperative history of irritable bowel syndrome is most important because these patients must never be promised regular function of their colostomies.
The technique of irrigation, usually performed in the morning, uses a cone tip that fits into the stoma only enough to provide a seal and to allow the instillation of 500–1000 mL of water. It is not necessary to dilate the stoma, and a finger is inserted only periodically to determine the direction for placement of the cone tip. Once the water has been instilled, a drainage bag is applied, and the individual can proceed with morning chores while the colostomy empties in response to the stimulation. Between irrigations the patient usually wears a security pouch, which permits passage of gas through a charcoal filter and provides a small pad to absorb any mucus normally secreted by the colonic mucosa.
Ischemia or infection causing partial loss of the intestinal wall or separation of the stoma from the skin can result in stricture of the colostomy. A tight stricture makes irrigation impossible and frequently causes the patient significant discomfort because of the resulting partial obstruction. Because the stricture is always at skin level, its correction is simple and no patient should suffer because of a colostomy stricture.
A common problem experienced by the patient with a colostomy is irregularity of function, which most often is related to irritable bowel syndrome or irradiation of the intestine. Many problems are related to improper location of the stoma, which allows seepage of mucus and maceration of the skin because an appliance seal cannot be adequately maintained. Parastomal hernia formation is common, and prolapse less so. Patients experience episodes of diarrhea and constipation depending on their underlying disease, dietary habits, and episodic infections. Patients with colostomies can be troubled with gas and odor problems because there is no sphincter around the stoma and gas can be passed uncontrollably. However, most appliances today are odor-proof, making odor only an issue during changing or emptying the appliance. This problem is usually regulated by diet, and in some cases by administering mild antidiarrheal agents when social activity dictates. Minimal bleeding around a stoma is common because the mucosa is exposed to environmental trauma. Of course, prolonged bleeding should be evaluated to be sure that there is not a recurrence of the primary disease process. The same is true of cramps and diarrhea. These can be acceptable occasionally, but anything of a prolonged or severe nature must be evaluated.
Evaluation of the UOA data registry shows that hernia formation is the most common complication of end colostomy, with obstruction, abscess, and fistula presenting less frequently. Of all the complications that occur, few require surgical correction. Fecal impaction can occur with a colostomy and can be managed by irrigation and laxatives. Digital disimpaction is rarely required.
In the past, it was believed unsafe to open the colon and suture the edges to the skin at the time of initial operation and stomas were thus opened in a delayed fashion. Serositis developed because the serosal surface of the exposed colon was irritated by exposure to air. After the exposed end of the colon was opened, it would take some time for the mucosa to eventually anneal to the epidermis. This process was called “maturation” of the colostomy. Strictures were common because the inflammation associated with serositis often led to fibrosis. Surgeons eventually learned to open stomas immediately at the time of initial operation and suture the intestinal wall to the skin. For historical reasons, this maneuver is still referred to as immediate “maturation” of the stoma.
Another cause of colostomy stricture is ischemia, usually as a result of resection of too much mesentery during construction of the stoma, or from inadequate mobilization and tension. Repair may require a simple local procedure if the stricture is focal at the skin level, or revision of the stoma via a transabdominal approach if the stricture involves a longer segment.
Ischemia or necrosis of the colostomy results from excessive resection of colonic mesentery, excessive tension on the mesentery leading to the stoma, creation of a fascial opening too small to accommodate the bowel and its mesentery, or poor perfusion due to low-flow states. The blood supply to an end colostomy is unidirectional, without collaterals; therefore, it will be most sensitive to changes in visceral perfusion. If the necrosis is limited to the area of the stoma anterior to the fascia, it may be observed carefully, and stoma revision performed electively at a later date, if necessary. If the necrosis extends into the peritoneal cavity, the abdomen should be explored and the stoma recreated. In some cases it is difficult to ascertain the extent of necrosis. Gentle flexible endoscopy via the stoma is an accurate method to determine the level of necrosis. Occasionally it may be possible to use a glass test tube and light to make this determination, but endoscopy is more reliable.
Paracolostomy hernia is a frequent complication of colostomy creation, even when all is done according to acceptable surgical principles. The creation of an abnormal opening in the abdominal wall that is then subjected on a daily basis to the pressures of Valsalva maneuvers may predispose the patient to suffer a gradual enlargement of the fascial opening. The relative weakness of the posterior rectus sheath in the inferior abdominal wall, with the potential space that exists alongside the rectus muscle, may also predispose the patient to develop a peritonealized sac in the rectus sheath without a large fascial defect. Although it is surgical dogma to create stomas in the rectus sheath to lessen the development of parastomal hernias, there are no definitive data to support this contention.
Asymptomatic parastomal hernias should be observed because the rate of recurrence after repair or relocation of the stoma is high. Patients should be counseled to seek immediate medical attention if they develop symptoms or signs of intestinal incarceration in the hernia. Symptomatic hernias may be relocated or repaired, although no technique has proven to be reliably successful. Local suture repair often fails, and although broad fascial mesh repair appears to be a more rigorous method of repair, there is still a substantial risk of recurrence and the added concern of mesh infection. Laparoscopic repair with intraperitoneal mesh is being used more frequently, although it would appear to offer no advantage over open mesh repair other than a potential reduction in wound complications and short-term postoperative recovery. Some surgeons are placing mesh in the abdominal wall at the time of permanent stoma creation as prophylaxis against hernia formation, but the experience is too preliminary to make definitive assessments of the safety and efficacy of this technique.
Prolapse of the colostomy is seen most often with the transverse loop colostomy. This is probably the result of several factors, most prominent being the lack of fixation of the transverse mesocolon to the retroperitoneum, and the size of the fascial opening necessary to bring both limbs of the colon and the mesocolon to the skin level. If the transverse loop colostomy is constructed to decompress a dilated colon, the fascial opening may need to be large initially, and then be excessive once the colon decompresses and thus predispose the colostomy to prolapse later. The surgical treatment of transverse loop colostomy prolapse is difficult, and the best treatment is to rid the patient of the primary disease and restore intestinal continuity. If this is not possible, the loop colostomy should be converted to an end colostomy with mucous fistula, or a divided end-loop colostomy, with concurrent tightening of the fascial defect.
Prolapse of an end colostomy can be managed by a local procedure in which the mucocutaneous junction is disconnected, the redundant colon resected, and the mucocutaneous junction recreated. Concurrent hernia repair can be performed as indicated.
Perforation of the colon just proximal to the stoma most often occurs during careless irrigation with a catheter or during contrast x-ray studies when a catheter is placed in the colostomy and a balloon is inflated. This occurrence represents a surgical emergency and must be dealt with by laparotomy and reconstruction of the colostomy with adequate drainage, if there is significant fecal or barium contamination. Cases of mild inflammation with extravasation of air can only be managed with antibiotics and localized drainage, and surgery can be avoided.