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Intestinal Stomas and their Complications
COMMON ABDOMINAL CONDITIONS
The major general complications of intestinal stomas and their predisposing causes
Intestinal Stomas and their Complications
Complication Parastomal herniation
N P Lees
Stomal prolapse
J Hill
Stomal retraction
Intestinal stomas are openings of the small or large bowel onto the anterior abdominal wall. Stomas may comprise a single intestinal lumen (end), or give access to both an afferent and an efferent lumen (loop). Furthermore, some are temporary, being subsequently reversed, whilst others are permanent. Complications (e.g. parastomal herniation, prolapse, retraction, stenosis) may occur with any of the commonly fashioned stomas (Figure 1), but the frequency of complications varies with the specific stoma type.
Stomal stenosis
1
as a mucous fistula (see below). The end colostomy formed in a Hartmann’s procedure is potentially reversible. It is usual to wait several months before attempting reversal, to allow intraperitoneal tissues to recover. Reversal of a Hartmann’s procedure is a major task, with an associated mortality of around 4%. The patients are often elderly and frail, and 40% never undergo reversal.
End colostomy Types of operation In abdominoperineal excision: the entire anorectal intestinal tube (including mesorectum and anal sphincters) is removed. After the colon has been transected proximally, the remaining proximal colon end is brought to the surface as a permanent end colostomy, usually in the left iliac fossa. Most patients choose to allow the colostomy to pass semi-formed stools by mass action into a bag, which is emptied or changed once or more daily. Some patients prefer to empty the colon at their convenience, by colostomy irrigation, wearing a convene plug in between times, thereby avoiding the need for a bag.
Formation of an end colostomy An end colostomy is fashioned by bringing the bowel through the abdominal wall through an appropriately-sized split in the rectus muscle (usually 2 fingers’ breadth) and suturing bowel primarily to the skin. The mucosa is level with the skin as formed stool is expected to pass, and leakage of stool onto the skin is acceptable. There should be an adequate blood supply so care must be taken to avoid tension and too small an opening in the rectus muscle. Complications Ischaemia: ischaemia and frank infarction of end colostomies is more likely if the ascending branch of the left colic artery is sacrificed (during high ligation of the inferior mesenteric artery on the abdominal aorta). Ischaemia usually manifests as partial separation of nonviable stoma and skin, with subsequent stomal stricturing and stenosis. This causes difficulties with stomal therapy, but may also lead to a mechanical large bowel obstruction. Dilatation is rarely successful, and further mobilization of well-vascularized bowel is usually necessary. Frank infarction of the stoma will lead to necrosis and possible retraction of the stoma back into the peritoneal cavity, causing peritonitis.
In a Hartmann’s procedure: a segmental large bowel resection is performed, but continuity is not immediately restored. Primary anastomosis may be inadvisable for any one of several reasons: • sepsis • an unprepared bowel • uncertainty over the adequacy of bowel vascularity • macroscopically obvious residual tumour at the end of a resection for cancer. After the diseased bowel segment is resected, the proximal end is brought out as an end colostomy. The distal end is usually closed over and left in situ as a blind-ending (rectal) stump. Alternatively, it may be brought to the anterior abdominal wall
Prolapse: prolapse of end colostomies is less common than prolapse of loop stomas. Causes include an oversized fascial opening and a long redundant loop of intraperitoneal colon. It may also be more common in patients with raised intraperitoneal pressure caused by obesity, ascites and chronic cough.
N P Lees is a Specialist Registrar in General Surgery at Manchester Royal Infirmary, Manchester, UK. He qualified from Oxford University, UK, in 1992. His interest is in the molecular carcinogenesis of colorectal neoplasia.
Parastomal herniation: this is the most common late complication of end colostomies, occuring in 30% of cases (Figure 2). It is more common if the stoma is brought out lateral to the rectus muscle, rather than through a split in the rectus, and may be predisposed by too wide an aponeurotic opening. It is also more
J Hill is a Consultant Surgeon at Manchester Royal Infirmary, Manchester, UK. He qualified from Bristol University and trained in Bristol, UK, Boston, USA, and Manchester. His research interests include inherited bowel cancer and pelvic floor disorders.
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Cause(s) Aponeurotic opening too large; raised intra-abdominal pressure Aponeurotic opening too large; excessive mobilization of redundant bowel Inadequate bowel mobilization; weight gain Aponeurotic opening too small; stomal ischaemia
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toxic megacolon, where immediate anastomosis is unsafe. The ileum is brought out as an end ileostomy. There are two main options for the rectal stump: • to close it (with a stapling device and/or a suture line) • or to bring out the proximal end onto the anterior abdominal wall as a mucous fistula. The latter effectively avoids the risk of a ‘blown’ rectal stump, i.e. the dehiscence of the staple or suture line. Such a dehiscence may occur after as many as 10% of total colectomies for acute colitis. This high incidence is related to the steroids such patients have received and the presence of active disease in the rectum. Dehiscence of the stump in such patients is associated with a high morbidity and mortality, though both may be reduced by washing out the rectal stump with aqueous betadine during the procedure. A mucous fistula may facilitate later reanastomosis to the rectum, as the residual bowel is longer. Unlike stomas carrying the faecal stream, mucous fistulas pass little or no effluent, sometimes discharging a small amount of mucus. They are quite frequently brought out through the lower end of the laparotomy wound.
2 Parastomal herniation around an end colostomy for low rectal cancer (abdominoperineal resection).
common with nutritional deficiency and weight gain. The incidence of parastomal herniation increases with time. The usual contents of the hernia sac are small bowel and omentum, though loops of colon and other abdominal viscera may also be found. Complications of parastomal herniation are relatively rare, but bowel may become incarcerated, obstructed or strangulated. Surgical management of the elderly, obese, malnourished patient with an obstructed parastomal hernia (Figure 2) is associated with high morbidity and mortality. Parastomal herniation may coincide with colostomy prolapse.
Complications: there are relatively few complications: • When a mucous fistula is fashioned with a barely adequate length of bowel, the stoma may retract. • A mucous fistula may develop diversion colitis, a condition seen in defunctioned bowel. It may be asymptomatic or associated with the passage of blood and mucus. The histology is variable, but includes epithelial degeneration and mucosal inflammation. Defunctioned mucosa is no longer in contact with luminal shortchain fatty acids and this appears largely responsible for diversion colitis. Short-chain fatty acids can be given locally as treatment if symptoms warrant.
Disease recurrence: recurrence, both of inflammatory bowel disease and of adenocarcinoma of the large bowel, is occasionally seen in end colostomies. Mucous fistula Mucous fistulas are different from other forms of intestinal stomas since they do not act as a conduit for the faecal stream. A mucous fistula is fashioned in association with another end stoma (ileostomy or colostomy, Figure 3), through which the enteral stream passes. A mucous fistula is usually fashioned during an emergency total colectomy for acute severe colitis or
Loop colostomy The most common indication for a loop colostomy is to protect a more distal anastomosis, after low anterior resection. A loop of transverse, descending or sigmoid colon is brought to the anterior abdominal wall, a longitudinal incision is made in the bowel wall, and the bowel edges are sutured to the skin. A purpose-made bridge or improvised piece of plastic drain or rubber catheter is used to keep the loop up to the level of the skin whilst healing takes place, usually being removed after 7–10 days. This reduces the risk of retraction and improves faecal diversion. The segment of large bowel chosen to bring out as a loop colostomy will depend on the site of pathology and the relative mobility of the colon. If there is a choice, the more distal option is usually favoured as the stool is more formed. Loop colostomies are usually intended to be temporary, bowel continuity being restored when a distal anastomosis is clinically and radiologically intact, usually 2–3 months after the primary surgery. A loop colostomy may be reversed during the same hospital admission in selected individuals such as elderly, frail patients who would not be able to manage a stoma. Loop colostomies are also used to defunction complex perianal fistula procedures, difficult sphincter repairs and Fournier’s gangrene. They can also be used in the management of faecal incontinence. Most can be fashioned through the trephine
3 An ileostomy in the right iliac fossa and mucous fistula in the right upper quadrant after ileocaecectomy for perforated ileocaecal Crohn’s disease.
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COMMON ABDOMINAL CONDITIONS
opening, with a low risk of complication assuming there is no tension at the skin level.
tip brought out in the umbilicus (Figure 4) or right iliac fossa as a stoma, through which the patient intermittently self-catheterizes, washing out the bowel. The main complication is stenosis of the appendix. Other complications include leakage (i.e. an incontinent stoma), and trauma from catheterization, including perforation. A conduit can be fashioned using small bowel rather than the appendix, but the surgery includes both an ileocaecal anastomosis and a reconstructive ileoileal anastomosis.
Complications Prolapse: prolapse of the efferent limb is the most common complication. It is more common after the proximal transverse colon is brought out in the right upper quadrant than after the distal transverse colon is brought up to the left upper quadrant, the fixation of the splenic flexure usually preventing efferent limb prolapse in the latter case. If the stoma is fashioned during the treatment of obstructed bowel, both prolapse and parastomal herniation may occur if the fascial defect created is excessively large for the decompressed bowel.
End ileostomy End ileostomy is usually performed during surgery for inflammatory bowel disease of the large bowel, such as total colectomy for acute severe colitis. Immediate ileorectal anastomosis is rarely favoured, because of the patient’s general condition and the likelihood that the remaining rectum is inflamed. Definitive restorative surgery, by means of proctectomy and ileal pouch anal anastomosis (in ulcerative colitis) or ileorectal anastomosis (in ulcerative colitis or Crohn’s colitis) is undertaken at a later stage, in patients whose general condition is favourable, whose rectum is healthy and whose histology is known. An end ileostomy may also be performed after a segmental resection of small bowel and/or proximal colon, when immediate ileoileal or ileocolic anastomosis is not favoured (Figure 3). Examples include ileocolic Crohn’s disease complicated by intraperitoneal abscess, and spontaneous segmental small and/or large bowel infarction due to thromboembolic disease.
Retraction: this may occur if the stoma is raised under tension, particularly in the obese patient. Retraction may lead to overflow of bowel effluent from proximal to distal limbs, and loss of diversionary efficacy.
Caecostomy Caecostomy allows decompression of the large bowel. It is seldom performed, because it carries a risk of intraperitoneal leakage of bowel contents: the caecum is thin-walled when obstructed and its blood supply may be compromised in such circumstances. However, it is sometimes used in the treatment of large bowel pseudo-obstruction (Ogilvie’s syndrome) and caecal volvulus. Caecostomy does not divert the faecal stream completely, as the back wall of the caecum remains within the peritoneal cavity and intestinal contents are able to pass on distally. Caecostomy is therefore not a satisfactory means of defunctioning a distal anastomosis (loop colostomy or loop ileostomy both being more suitable for this purpose).
Formation of ileostomy The principles of ileostomy formation are identical to those for colostomies. Because of the liquid contents, it is essential to fashion a Brooke-type evaginated stoma, with a spout 2–3 cm in length, positioned away from skin creases, ribcage and iliac crest. This is to facilitate application of a well-fitting appliance and avoid skin damage from the effluent (which contains activated digestive enzymes and may be at alkaline pH) and stoma damage from the appliance. The value of having a patient preoperatively marked for best ileostomy sites by a trained stoma therapist (see below) cannot be overstated. However, there are occasions when emergency surgery is required and a stoma therapist is unavailable. During emergency cases the small bowel is often oedematous and friable, but every effort should be made to produce at least some spout. Where ileal oedema makes eversion difficult, incisions along the serosa of the ileostomy may be helpful. Surgeons can greatly reduce the postoperative complications of end ileostomies by attention to positioning and stoma size.
Antegrade continent enema appendicostomy or ileostomy A specific and relatively unusual stoma is that fashioned from the appendix to administer antegrade continent enemas (the ACE procedure). It is used in patients with neuropathic bowels (e.g. from spina bifida) who are troubled by slow colonic transit, and constipation or overflow diarrhoea. In the ACE procedure, the appendix is mobilized, maintaining its blood supply, and the
Complications Stenosis and retraction: these are usually due to inadequate mobilization of small bowel, and may occur in 10% of cases. A patient rendered healthy after colectomy for severe colitis may gain considerable weight, and a stoma that was a little short may become retracted with time. Retraction may be fixed or intermittent. If retraction is intermittent, it is sometimes possible to maintain a spout by firing a 55 mm linear stapler (without a cutting blade) 1–3 times, along the length of the everted stoma. Even when an end ileostomy is fashioned carefully, its blood supply may prove inadequate in the septic patient requiring high doses of vasoconstricting inotropes, such as noradrenaline (Figure 5).
4 Formation of an appendicostomy for administering antegrade continent enemas (the ACE procedure).
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parastomal hernia sacs. A loop of intraperitoneal small bowel may twist around the terminal ileum where it passes up to the abdominal wall, and become obstructed or strangulated. Some surgeons choose to close off this ‘lateral space’, by suturing the terminal ileal mesentery to the peritoneum of the abdominal wall. Inflammatory bowel disease at the stoma: in patients with Crohn’s disease, recurrence tends to occur proximal to the stoma and can be visualized by retrograde enteroscopy and retrograde barium studies. Stenosing or fissuring disease may occur. Parastomal pyoderma gangrenosum and parastomal ulcers are also seen in association with recurrence of inflammatory bowel disease. Varices: chronic inflammatory bowel disease is associated with the development of sclerosing cholangitis. Patients with cirrhosis due to this or other reasons may develop portal–systemic shunting between ileal and cutaneous vessels with parastomal varices and a risk of life-threatening haemorrhage. The treatment of the varices is to treat the portal hypertension, often by transjugular intrahepatic portosystemic shunting (TIPS).
5 A necrotic end ileostomy in a patient presenting with caecal perforation from an obstructing sigmoid cancer. The patient was grossly septic and required enormous doses of noradrenaline postoperatively. Note the wound dehiscence (arrow).
Nutritional deficiencies: formation of an ileostomy often coincides with an ileal resection, which may result in B12 and/or bile acid deficiency, with risks of anaemia and gallstones respectively. Where ileostomy output is high (particularly if >1 l per day) dehydration and deficiencies of calcium and magnesium may ensue.
A severely retracted or stenosed ileostomy (and certainly a frankly necrotic ileostomy) will require surgical revision. Prolapse: this may be fixed or reducible. The latter may be more common after revisionary mobilization (e.g. for retraction) and can be treated by linear stapler fixation, as with retraction. Some ileostomies alternately prolapse and retract.
Loop ileostomy
Mucocutaneous fistulas: these are seen in association with ileostomies. Recurrence of Crohn’s disease in the neoterminal ileum may be the cause, though the inadvertent placement of full-thickness sutures to facilitate eversion of a Brooke ileostomy may result in local subcutaneous abscess formation with progression to parastomal fistulation. Paraileostomy fistulas can cause difficulties keeping effluent off the skin, and thus lead to severe dermatitis.
Studies have shown loop ileostomies to be associated with lower risks of complication (prolapse, parastomal herniation, incisional herniation) than loop transverse colostomy when used as a means of faecal diversion after low anterior resection. However, some researchers feel that the liquid effluent of an ileostomy presents greater inconvenience with regard to stoma appliance management than a loop colostomy, and the latter remains popular in surgical practice.
Other dermatological problems: mucosal seeding, in which mucosal cells grow along the suture line between the ileum and skin edge, may occur. Paraileostomy herniation: this has similar risk factors to paracolostomy hernias. The incidence of paraileostomy herniation may be of the order of 30%, when prospectively and rigorously looked for. The hernia sac may result in small bowel incarceration, obstruction or strangulation. As with paracolostomy hernias, there are several methods of surgical repair for paraileostomy herniation. They include simple suture repair of the rectus sheath, and the use of prolene meshes, either as onlays, or as preperitoneal (synonymous with properitoneal, see Mahadevan, page 25) inlays. Simple suture is associated with high recurrence rates. Techniques using mesh have lower recurrence rates, but carry a risk of mesh infection and of stomal stenosis. If local measures fail, laparotomy and resiting of the ileostomy may be required. 6 Prolapse of a loop ileostomy, fashioned to protect an ileal pouch anal anastomosis. The stoma was reversed uneventfully.
Small bowel obstruction: this may occur even in patients without
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Management of Intestinal Fistulas
Complications of stomas Parastomal skin complications A number of skin conditions adjacent to stomas occur where pathology originates in, or is associated with, the intestine (e.g. parastomal abscesses, pyoderma gangrenosum). Other skin complications are more closely linked to the efficacy of enterostomal therapy (though a malpositioned or otherwise suboptimal stoma is difficult to fit appliances to).
S Chintapatla Nigel A Scott
Allergy to appliance products may result in a contact dermatitis, whilst skin contact by bowel effluent, particularly small bowel, will result in a chemical dermatitis. Removal of adherent appliances may traumatize hair and cause a parastomal folliculitis. The warm, moist environment around stomas may lead to Candida albicans overgrowth.
A gastrointestinal (GI) fistula is an abnormal communication between the epithelial-lined lumen of the GI tract and the epithelium of an adjacent viscus or the skin. Fistulas may be congenital or acquired (Figure 1). • A primary GI fistula arises as a consequence of disease in the wall of the gut (e.g. Crohn’s disease, malignancy). • A secondary GI fistula occurs as a consequence of injury to otherwise normal gut (e.g. surgical resection).
Psychosocial complications and quality of life The psychosocial morbidity associated with stomas should not be underestimated. The patient may feel they should feel ‘gratitude’ to their surgeons for physical well-being and thus be inhibited from expressing worries on matters such as body image and sexual attractiveness. Fear that the stoma is noticeable or malodorous is common, and some become impotent for psychological (not physical) reasons.
Primary GI fistulation Crohn’s disease: the pathophysiology of the primary Crohn’s fistula begins with a fissuring ulcer penetrating the full thickness of the gut wall. This breach of the intestine is followed by abscess formation. It is the abscess breaking through into an adjacent viscus (e.g. sigmoid colon, bladder, normal small bowel) or through the abdominal wall that establishes the fistula tract. A significant proportion of patients with Crohn’s disease have perforating or fistulating disease. This fistulating disease often involves the terminal ileum, but can also involve the small bowel proximal to an ileocolonic anastomosis and can occasionally arise from Crohn’s colitis. Such a patient usually presents with a palpable mass consisting of both fistulating gut and abscess cavity in the right iliac fossa. Neglect of a fistulating Crohn’s mass (Figure 2) inevitably leads to progressive involvement of adjacent normal small and large bowel and increases the extent of the resection. The clinician has to be especially alert to the problem of fistulating Crohn’s disease from an ileocolonic anastomosis, with involvement of the second or third part of the duodenum. Management – the strategy for resection of a primary Crohn’s fistula is influenced by the degree of sepsis (Figure 3). Anastomotic suture lines must be avoided in hypoalbuminaemic, septic patients. Such patients are at risk of anastomotic dehiscence and so the probability of a temporary ileostomy should be discussed and the best site for it should be marked preoperatively.
7
The stoma should be fashioned to ensure that the proximal limb (from which effluent will be eliminated) lies inferiorly, minimizing the chance of small bowel fluid overflowing into the distal limb. The ileum should not be twisted to achieve this. Complications of loop ileostomies are relatively rare. Since they are usually fashioned as a temporary diversion, being reversed some months later, parastomal herniation rarely has time to develop. Small bowel obstruction is perhaps the most common significant complication. Problems with stomal retraction and parastomal abscesses are also seen, and stomal prolapse occurs occasionally (Figure 6). During stoma formation, the proximal limb may prove difficult to evert, and appliance-related problems might ensue. Reversal of loop stomas is usually straightforward and can be performed through the trephine opening in most cases. Patients should be warned about the possible risk of laparotomy. Role of stoma therapists An experienced stoma therapist can provide valuable help after stoma formation and, where possible, preoperatively. The therapist determines the optimal site for a stoma preoperatively, avoiding bony prominences (e.g. iliac crest, ribcage), scars, skin creases and anticipated surgical wounds, taking into account patients’ clothing habits (e.g. waistband position). They usually have a much better knowledge of the appliances available and adjuncts to enterostomal care. By meticulous protection of parastomal skin (Figure 7), they are usually pivotal in the treatment of parastomal dermatitides. By developing a rapport with patients both in the hospital and in the community, they are also often best placed to address patients’ psychological anxieties (Figure 7). u
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Diverticular disease of the colon: the most common fistula associated with colonic diverticular disease is a sigmoid fistula into the dome of the bladder (colovesical fistula), which is clinically S Chintapatla is a Specialist Registrar in colorectal surgery at Hope Hospital, Manchester, UK. Nigel A Scott is Consultant Colorectal and Intestinal Failure Surgeon at Hope Hospital, Manchester, UK.
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The major general complications of intestinal stomas and their predisposing causes
Intestinal Stomas and their Complications
Complication Parastomal herniation
N P Lees
Stomal prolapse
J Hill
Stomal retraction
Intestinal stomas are openings of the small or large bowel onto the anterior abdominal wall. Stomas may comprise a single intestinal lumen (end), or give access to both an afferent and an efferent lumen (loop). Furthermore, some are temporary, being subsequently reversed, whilst others are permanent. Complications (e.g. parastomal herniation, prolapse, retraction, stenosis) may occur with any of the commonly fashioned stomas (Figure 1), but the frequency of complications varies with the specific stoma type.
Stomal stenosis
1
as a mucous fistula (see below). The end colostomy formed in a Hartmann’s procedure is potentially reversible. It is usual to wait several months before attempting reversal, to allow intraperitoneal tissues to recover. Reversal of a Hartmann’s procedure is a major task, with an associated mortality of around 4%. The patients are often elderly and frail, and 40% never undergo reversal.
End colostomy Types of operation In abdominoperineal excision: the entire anorectal intestinal tube (including mesorectum and anal sphincters) is removed. After the colon has been transected proximally, the remaining proximal colon end is brought to the surface as a permanent end colostomy, usually in the left iliac fossa. Most patients choose to allow the colostomy to pass semi-formed stools by mass action into a bag, which is emptied or changed once or more daily. Some patients prefer to empty the colon at their convenience, by colostomy irrigation, wearing a convene plug in between times, thereby avoiding the need for a bag.
Formation of an end colostomy An end colostomy is fashioned by bringing the bowel through the abdominal wall through an appropriately-sized split in the rectus muscle (usually 2 fingers’ breadth) and suturing bowel primarily to the skin. The mucosa is level with the skin as formed stool is expected to pass, and leakage of stool onto the skin is acceptable. There should be an adequate blood supply so care must be taken to avoid tension and too small an opening in the rectus muscle. Complications Ischaemia: ischaemia and frank infarction of end colostomies is more likely if the ascending branch of the left colic artery is sacrificed (during high ligation of the inferior mesenteric artery on the abdominal aorta). Ischaemia usually manifests as partial separation of nonviable stoma and skin, with subsequent stomal stricturing and stenosis. This causes difficulties with stomal therapy, but may also lead to a mechanical large bowel obstruction. Dilatation is rarely successful, and further mobilization of well-vascularized bowel is usually necessary. Frank infarction of the stoma will lead to necrosis and possible retraction of the stoma back into the peritoneal cavity, causing peritonitis.
In a Hartmann’s procedure: a segmental large bowel resection is performed, but continuity is not immediately restored. Primary anastomosis may be inadvisable for any one of several reasons: • sepsis • an unprepared bowel • uncertainty over the adequacy of bowel vascularity • macroscopically obvious residual tumour at the end of a resection for cancer. After the diseased bowel segment is resected, the proximal end is brought out as an end colostomy. The distal end is usually closed over and left in situ as a blind-ending (rectal) stump. Alternatively, it may be brought to the anterior abdominal wall
Prolapse: prolapse of end colostomies is less common than prolapse of loop stomas. Causes include an oversized fascial opening and a long redundant loop of intraperitoneal colon. It may also be more common in patients with raised intraperitoneal pressure caused by obesity, ascites and chronic cough.
N P Lees is a Specialist Registrar in General Surgery at Manchester Royal Infirmary, Manchester, UK. He qualified from Oxford University, UK, in 1992. His interest is in the molecular carcinogenesis of colorectal neoplasia.
Parastomal herniation: this is the most common late complication of end colostomies, occuring in 30% of cases (Figure 2). It is more common if the stoma is brought out lateral to the rectus muscle, rather than through a split in the rectus, and may be predisposed by too wide an aponeurotic opening. It is also more
J Hill is a Consultant Surgeon at Manchester Royal Infirmary, Manchester, UK. He qualified from Bristol University and trained in Bristol, UK, Boston, USA, and Manchester. His research interests include inherited bowel cancer and pelvic floor disorders.
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Cause(s) Aponeurotic opening too large; raised intra-abdominal pressure Aponeurotic opening too large; excessive mobilization of redundant bowel Inadequate bowel mobilization; weight gain Aponeurotic opening too small; stomal ischaemia
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COMMON ABDOMINAL CONDITIONS
toxic megacolon, where immediate anastomosis is unsafe. The ileum is brought out as an end ileostomy. There are two main options for the rectal stump: • to close it (with a stapling device and/or a suture line) • or to bring out the proximal end onto the anterior abdominal wall as a mucous fistula. The latter effectively avoids the risk of a ‘blown’ rectal stump, i.e. the dehiscence of the staple or suture line. Such a dehiscence may occur after as many as 10% of total colectomies for acute colitis. This high incidence is related to the steroids such patients have received and the presence of active disease in the rectum. Dehiscence of the stump in such patients is associated with a high morbidity and mortality, though both may be reduced by washing out the rectal stump with aqueous betadine during the procedure. A mucous fistula may facilitate later reanastomosis to the rectum, as the residual bowel is longer. Unlike stomas carrying the faecal stream, mucous fistulas pass little or no effluent, sometimes discharging a small amount of mucus. They are quite frequently brought out through the lower end of the laparotomy wound.
2 Parastomal herniation around an end colostomy for low rectal cancer (abdominoperineal resection).
common with nutritional deficiency and weight gain. The incidence of parastomal herniation increases with time. The usual contents of the hernia sac are small bowel and omentum, though loops of colon and other abdominal viscera may also be found. Complications of parastomal herniation are relatively rare, but bowel may become incarcerated, obstructed or strangulated. Surgical management of the elderly, obese, malnourished patient with an obstructed parastomal hernia (Figure 2) is associated with high morbidity and mortality. Parastomal herniation may coincide with colostomy prolapse.
Complications: there are relatively few complications: • When a mucous fistula is fashioned with a barely adequate length of bowel, the stoma may retract. • A mucous fistula may develop diversion colitis, a condition seen in defunctioned bowel. It may be asymptomatic or associated with the passage of blood and mucus. The histology is variable, but includes epithelial degeneration and mucosal inflammation. Defunctioned mucosa is no longer in contact with luminal shortchain fatty acids and this appears largely responsible for diversion colitis. Short-chain fatty acids can be given locally as treatment if symptoms warrant.
Disease recurrence: recurrence, both of inflammatory bowel disease and of adenocarcinoma of the large bowel, is occasionally seen in end colostomies. Mucous fistula Mucous fistulas are different from other forms of intestinal stomas since they do not act as a conduit for the faecal stream. A mucous fistula is fashioned in association with another end stoma (ileostomy or colostomy, Figure 3), through which the enteral stream passes. A mucous fistula is usually fashioned during an emergency total colectomy for acute severe colitis or
Loop colostomy The most common indication for a loop colostomy is to protect a more distal anastomosis, after low anterior resection. A loop of transverse, descending or sigmoid colon is brought to the anterior abdominal wall, a longitudinal incision is made in the bowel wall, and the bowel edges are sutured to the skin. A purpose-made bridge or improvised piece of plastic drain or rubber catheter is used to keep the loop up to the level of the skin whilst healing takes place, usually being removed after 7–10 days. This reduces the risk of retraction and improves faecal diversion. The segment of large bowel chosen to bring out as a loop colostomy will depend on the site of pathology and the relative mobility of the colon. If there is a choice, the more distal option is usually favoured as the stool is more formed. Loop colostomies are usually intended to be temporary, bowel continuity being restored when a distal anastomosis is clinically and radiologically intact, usually 2–3 months after the primary surgery. A loop colostomy may be reversed during the same hospital admission in selected individuals such as elderly, frail patients who would not be able to manage a stoma. Loop colostomies are also used to defunction complex perianal fistula procedures, difficult sphincter repairs and Fournier’s gangrene. They can also be used in the management of faecal incontinence. Most can be fashioned through the trephine
3 An ileostomy in the right iliac fossa and mucous fistula in the right upper quadrant after ileocaecectomy for perforated ileocaecal Crohn’s disease.
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opening, with a low risk of complication assuming there is no tension at the skin level.
tip brought out in the umbilicus (Figure 4) or right iliac fossa as a stoma, through which the patient intermittently self-catheterizes, washing out the bowel. The main complication is stenosis of the appendix. Other complications include leakage (i.e. an incontinent stoma), and trauma from catheterization, including perforation. A conduit can be fashioned using small bowel rather than the appendix, but the surgery includes both an ileocaecal anastomosis and a reconstructive ileoileal anastomosis.
Complications Prolapse: prolapse of the efferent limb is the most common complication. It is more common after the proximal transverse colon is brought out in the right upper quadrant than after the distal transverse colon is brought up to the left upper quadrant, the fixation of the splenic flexure usually preventing efferent limb prolapse in the latter case. If the stoma is fashioned during the treatment of obstructed bowel, both prolapse and parastomal herniation may occur if the fascial defect created is excessively large for the decompressed bowel.
End ileostomy End ileostomy is usually performed during surgery for inflammatory bowel disease of the large bowel, such as total colectomy for acute severe colitis. Immediate ileorectal anastomosis is rarely favoured, because of the patient’s general condition and the likelihood that the remaining rectum is inflamed. Definitive restorative surgery, by means of proctectomy and ileal pouch anal anastomosis (in ulcerative colitis) or ileorectal anastomosis (in ulcerative colitis or Crohn’s colitis) is undertaken at a later stage, in patients whose general condition is favourable, whose rectum is healthy and whose histology is known. An end ileostomy may also be performed after a segmental resection of small bowel and/or proximal colon, when immediate ileoileal or ileocolic anastomosis is not favoured (Figure 3). Examples include ileocolic Crohn’s disease complicated by intraperitoneal abscess, and spontaneous segmental small and/or large bowel infarction due to thromboembolic disease.
Retraction: this may occur if the stoma is raised under tension, particularly in the obese patient. Retraction may lead to overflow of bowel effluent from proximal to distal limbs, and loss of diversionary efficacy.
Caecostomy Caecostomy allows decompression of the large bowel. It is seldom performed, because it carries a risk of intraperitoneal leakage of bowel contents: the caecum is thin-walled when obstructed and its blood supply may be compromised in such circumstances. However, it is sometimes used in the treatment of large bowel pseudo-obstruction (Ogilvie’s syndrome) and caecal volvulus. Caecostomy does not divert the faecal stream completely, as the back wall of the caecum remains within the peritoneal cavity and intestinal contents are able to pass on distally. Caecostomy is therefore not a satisfactory means of defunctioning a distal anastomosis (loop colostomy or loop ileostomy both being more suitable for this purpose).
Formation of ileostomy The principles of ileostomy formation are identical to those for colostomies. Because of the liquid contents, it is essential to fashion a Brooke-type evaginated stoma, with a spout 2–3 cm in length, positioned away from skin creases, ribcage and iliac crest. This is to facilitate application of a well-fitting appliance and avoid skin damage from the effluent (which contains activated digestive enzymes and may be at alkaline pH) and stoma damage from the appliance. The value of having a patient preoperatively marked for best ileostomy sites by a trained stoma therapist (see below) cannot be overstated. However, there are occasions when emergency surgery is required and a stoma therapist is unavailable. During emergency cases the small bowel is often oedematous and friable, but every effort should be made to produce at least some spout. Where ileal oedema makes eversion difficult, incisions along the serosa of the ileostomy may be helpful. Surgeons can greatly reduce the postoperative complications of end ileostomies by attention to positioning and stoma size.
Antegrade continent enema appendicostomy or ileostomy A specific and relatively unusual stoma is that fashioned from the appendix to administer antegrade continent enemas (the ACE procedure). It is used in patients with neuropathic bowels (e.g. from spina bifida) who are troubled by slow colonic transit, and constipation or overflow diarrhoea. In the ACE procedure, the appendix is mobilized, maintaining its blood supply, and the
Complications Stenosis and retraction: these are usually due to inadequate mobilization of small bowel, and may occur in 10% of cases. A patient rendered healthy after colectomy for severe colitis may gain considerable weight, and a stoma that was a little short may become retracted with time. Retraction may be fixed or intermittent. If retraction is intermittent, it is sometimes possible to maintain a spout by firing a 55 mm linear stapler (without a cutting blade) 1–3 times, along the length of the everted stoma. Even when an end ileostomy is fashioned carefully, its blood supply may prove inadequate in the septic patient requiring high doses of vasoconstricting inotropes, such as noradrenaline (Figure 5).
4 Formation of an appendicostomy for administering antegrade continent enemas (the ACE procedure).
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COMMON ABDOMINAL CONDITIONS
parastomal hernia sacs. A loop of intraperitoneal small bowel may twist around the terminal ileum where it passes up to the abdominal wall, and become obstructed or strangulated. Some surgeons choose to close off this ‘lateral space’, by suturing the terminal ileal mesentery to the peritoneum of the abdominal wall. Inflammatory bowel disease at the stoma: in patients with Crohn’s disease, recurrence tends to occur proximal to the stoma and can be visualized by retrograde enteroscopy and retrograde barium studies. Stenosing or fissuring disease may occur. Parastomal pyoderma gangrenosum and parastomal ulcers are also seen in association with recurrence of inflammatory bowel disease. Varices: chronic inflammatory bowel disease is associated with the development of sclerosing cholangitis. Patients with cirrhosis due to this or other reasons may develop portal–systemic shunting between ileal and cutaneous vessels with parastomal varices and a risk of life-threatening haemorrhage. The treatment of the varices is to treat the portal hypertension, often by transjugular intrahepatic portosystemic shunting (TIPS).
5 A necrotic end ileostomy in a patient presenting with caecal perforation from an obstructing sigmoid cancer. The patient was grossly septic and required enormous doses of noradrenaline postoperatively. Note the wound dehiscence (arrow).
Nutritional deficiencies: formation of an ileostomy often coincides with an ileal resection, which may result in B12 and/or bile acid deficiency, with risks of anaemia and gallstones respectively. Where ileostomy output is high (particularly if >1 l per day) dehydration and deficiencies of calcium and magnesium may ensue.
A severely retracted or stenosed ileostomy (and certainly a frankly necrotic ileostomy) will require surgical revision. Prolapse: this may be fixed or reducible. The latter may be more common after revisionary mobilization (e.g. for retraction) and can be treated by linear stapler fixation, as with retraction. Some ileostomies alternately prolapse and retract.
Loop ileostomy
Mucocutaneous fistulas: these are seen in association with ileostomies. Recurrence of Crohn’s disease in the neoterminal ileum may be the cause, though the inadvertent placement of full-thickness sutures to facilitate eversion of a Brooke ileostomy may result in local subcutaneous abscess formation with progression to parastomal fistulation. Paraileostomy fistulas can cause difficulties keeping effluent off the skin, and thus lead to severe dermatitis.
Studies have shown loop ileostomies to be associated with lower risks of complication (prolapse, parastomal herniation, incisional herniation) than loop transverse colostomy when used as a means of faecal diversion after low anterior resection. However, some researchers feel that the liquid effluent of an ileostomy presents greater inconvenience with regard to stoma appliance management than a loop colostomy, and the latter remains popular in surgical practice.
Other dermatological problems: mucosal seeding, in which mucosal cells grow along the suture line between the ileum and skin edge, may occur. Paraileostomy herniation: this has similar risk factors to paracolostomy hernias. The incidence of paraileostomy herniation may be of the order of 30%, when prospectively and rigorously looked for. The hernia sac may result in small bowel incarceration, obstruction or strangulation. As with paracolostomy hernias, there are several methods of surgical repair for paraileostomy herniation. They include simple suture repair of the rectus sheath, and the use of prolene meshes, either as onlays, or as preperitoneal (synonymous with properitoneal, see Mahadevan, page 25) inlays. Simple suture is associated with high recurrence rates. Techniques using mesh have lower recurrence rates, but carry a risk of mesh infection and of stomal stenosis. If local measures fail, laparotomy and resiting of the ileostomy may be required. 6 Prolapse of a loop ileostomy, fashioned to protect an ileal pouch anal anastomosis. The stoma was reversed uneventfully.
Small bowel obstruction: this may occur even in patients without
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COMMON ABDOMINAL CONDITIONS
Management of Intestinal Fistulas
Complications of stomas Parastomal skin complications A number of skin conditions adjacent to stomas occur where pathology originates in, or is associated with, the intestine (e.g. parastomal abscesses, pyoderma gangrenosum). Other skin complications are more closely linked to the efficacy of enterostomal therapy (though a malpositioned or otherwise suboptimal stoma is difficult to fit appliances to).
S Chintapatla Nigel A Scott
Allergy to appliance products may result in a contact dermatitis, whilst skin contact by bowel effluent, particularly small bowel, will result in a chemical dermatitis. Removal of adherent appliances may traumatize hair and cause a parastomal folliculitis. The warm, moist environment around stomas may lead to Candida albicans overgrowth.
A gastrointestinal (GI) fistula is an abnormal communication between the epithelial-lined lumen of the GI tract and the epithelium of an adjacent viscus or the skin. Fistulas may be congenital or acquired (Figure 1). • A primary GI fistula arises as a consequence of disease in the wall of the gut (e.g. Crohn’s disease, malignancy). • A secondary GI fistula occurs as a consequence of injury to otherwise normal gut (e.g. surgical resection).
Psychosocial complications and quality of life The psychosocial morbidity associated with stomas should not be underestimated. The patient may feel they should feel ‘gratitude’ to their surgeons for physical well-being and thus be inhibited from expressing worries on matters such as body image and sexual attractiveness. Fear that the stoma is noticeable or malodorous is common, and some become impotent for psychological (not physical) reasons.
Primary GI fistulation Crohn’s disease: the pathophysiology of the primary Crohn’s fistula begins with a fissuring ulcer penetrating the full thickness of the gut wall. This breach of the intestine is followed by abscess formation. It is the abscess breaking through into an adjacent viscus (e.g. sigmoid colon, bladder, normal small bowel) or through the abdominal wall that establishes the fistula tract. A significant proportion of patients with Crohn’s disease have perforating or fistulating disease. This fistulating disease often involves the terminal ileum, but can also involve the small bowel proximal to an ileocolonic anastomosis and can occasionally arise from Crohn’s colitis. Such a patient usually presents with a palpable mass consisting of both fistulating gut and abscess cavity in the right iliac fossa. Neglect of a fistulating Crohn’s mass (Figure 2) inevitably leads to progressive involvement of adjacent normal small and large bowel and increases the extent of the resection. The clinician has to be especially alert to the problem of fistulating Crohn’s disease from an ileocolonic anastomosis, with involvement of the second or third part of the duodenum. Management – the strategy for resection of a primary Crohn’s fistula is influenced by the degree of sepsis (Figure 3). Anastomotic suture lines must be avoided in hypoalbuminaemic, septic patients. Such patients are at risk of anastomotic dehiscence and so the probability of a temporary ileostomy should be discussed and the best site for it should be marked preoperatively.
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The stoma should be fashioned to ensure that the proximal limb (from which effluent will be eliminated) lies inferiorly, minimizing the chance of small bowel fluid overflowing into the distal limb. The ileum should not be twisted to achieve this. Complications of loop ileostomies are relatively rare. Since they are usually fashioned as a temporary diversion, being reversed some months later, parastomal herniation rarely has time to develop. Small bowel obstruction is perhaps the most common significant complication. Problems with stomal retraction and parastomal abscesses are also seen, and stomal prolapse occurs occasionally (Figure 6). During stoma formation, the proximal limb may prove difficult to evert, and appliance-related problems might ensue. Reversal of loop stomas is usually straightforward and can be performed through the trephine opening in most cases. Patients should be warned about the possible risk of laparotomy. Role of stoma therapists An experienced stoma therapist can provide valuable help after stoma formation and, where possible, preoperatively. The therapist determines the optimal site for a stoma preoperatively, avoiding bony prominences (e.g. iliac crest, ribcage), scars, skin creases and anticipated surgical wounds, taking into account patients’ clothing habits (e.g. waistband position). They usually have a much better knowledge of the appliances available and adjuncts to enterostomal care. By meticulous protection of parastomal skin (Figure 7), they are usually pivotal in the treatment of parastomal dermatitides. By developing a rapport with patients both in the hospital and in the community, they are also often best placed to address patients’ psychological anxieties (Figure 7). u
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Diverticular disease of the colon: the most common fistula associated with colonic diverticular disease is a sigmoid fistula into the dome of the bladder (colovesical fistula), which is clinically S Chintapatla is a Specialist Registrar in colorectal surgery at Hope Hospital, Manchester, UK. Nigel A Scott is Consultant Colorectal and Intestinal Failure Surgeon at Hope Hospital, Manchester, UK.
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