Overview of surgical ostomy for fecal diversion

INTRODUCTION — An ostomy is a purposeful anastomosis between a segment of the gastrointestinal tract and the skin of the anterior abdominal wall [1]. An ostomy can be created virtually anywhere along the gastrointestinal tract. For diversion of the fecal stream, the most common ostomies involve the distal small intestine (eg, ileostomy) and large intestine (ie, colostomy).

Temporary or permanent fecal diversions may be needed to manage a variety of pathologic conditions, including congenital anomalies, colon obstruction, inflammatory bowel disease, traumatic disruption of the intestinal tract, or gastrointestinal malignancy [2]. Overall, the number of fecal diversions appears to be declining.

The principles of ostomy construction for the purpose of fecal diversion, including types, site selection, and creation, is reviewed here. The routine care and management of common ostomy complications are reviewed separately. (See "Ileostomy or colostomy care and complications" and "Parastomal hernia".)

FECAL DIVERSIONS — Fecal diversion by the creation of an ostomy, which is a purposeful anastomosis between a segment of the gastrointestinal tract and the skin of the anterior abdominal wall, is indicated when restoration of intestinal continuity is contraindicated or not immediately feasible given the patient's clinical condition. As an example, patients who are at high risk for anastomotic leak (eg, malnourished, high-dose steroids), who have an intestinal anastomosis <5 to 7 cm from the anal verge (low anastomosis below the peritoneal reflection), or who are hemodynamically unstable (eg, trauma, sepsis) may benefit from a temporary ostomy until continuity of bowel can be restored safely [3,4].

Fecal diversions are commonly classified according to the segment of the bowel used to create the ostomy (eg, sigmoid, colon, ileum) and the manner of surgical construction (eg, loop, end, reservoir).

Ileostomy — An ileostomy (temporary or permanent) is performed when it is necessary to remove or bypass the entire colon and rectum or to protect a distal colorectal, coloanal, or ileoanal anastomosis (picture 1). An ileostomy can be constructed either as a diverting loop stoma or end stoma, with or without a continent reservoir.

Diverting loop ileostomy — Temporary loop ileostomy is preferred over colostomy for protecting a distal colorectal anastomosis or coloanal anastomosis following a sphincter-saving rectal resection [5-9]. A loop of terminal ileum is brought out through the abdominal wall, opened, and sutured to the dermis and stabilized with a rod or bridge until the bowel granulates to the abdominal wall. (See 'Loop ostomy' below.)

Temporary diversion is generally reserved for patients considered high risk for anastomotic breakdown, such as patients with previous irradiation of the pelvis; those on medications that impair wound healing such as steroids, immunosuppressive, or biologic agents; or those with a low colorectal anastomosis (<5 to 7 cm from anal verge) [10-12]. It is frequently used following ileoanal pouch procedures (figure 1). Although data are inconclusive on the effects of immunosuppressive medications on anastomotic healing, many surgeons still protect the primary anastomosis with a temporary diverting loop ostomy [13-16]. (See "Management of anastomotic complications of colorectal surgery", section on 'Risk factors'.)

End-ileostomy — If the anorectal sphincter mechanism is removed with the entire colon and rectum, a permanent end ileostomy is needed. An alternative approach is the continent ileal reservoir. (See 'Continent ileostomy' below.)

Brooke's technique, which involves eversion of the bowel to expose the mucosa followed by mucocutaneous suturing to create an end stoma, is the accepted approach for creation of an end stoma (figure 2). A Brooke ileostomy protrudes 2 to 3 cm above skin level, which promotes drainage of the effluent into the pouch and allows secure application of the stoma appliance. This reduces skin irritation by minimizing spillage of enzymatic effluent beneath the pouching system and prevents the development of serositis and potential stricture. The afferent or proximal limb of a diverting loop ileostomy is also often created with a Brooke's everting stitch while the distal efferent limb is sutured directly to the skin.

Continent ileostomy — The continent (permanent) ileostomy is performed by surgeons who specialize in this type of procedure. The stoma and ileal reservoir are intubated by the patient on a regular basis to provide elimination of reservoir contents. Continent ileal reservoirs are associated with a fairly high reoperation rate, most commonly due to slippage of the continence mechanism [17]. As a result, they are limited to patients who desire a continent procedure and who are not candidates for an ileal-anal pouch (figure 3) [17-19]. A continent ileal reservoir is contraindicated in patients with Crohn disease. (See "Ileostomy or colostomy care and complications", section on 'Nipple valve slippage'.)

The continent ileal reservoir, originally performed by Nils Kock, involves the creation of an internal pouch fashioned from detubularized ileum and rendered continent by intussuscepting the segment of ileum connecting the reservoir to the abdominal stoma. The original procedure was modified by Barnett, who added an ileal "collar" (a segment of ileum looped around the intussuscepted segment of bowel and connecting to the reservoir) that improved continence (Barnett continent ileal reservoir [BCIR]) (figure 4).

Colostomy — A colostomy is performed when it is necessary to bypass or remove the distal colon, rectum, or anus and it is either inadvisable or not feasible to restore gastrointestinal continuity. If the distal rectum and anorectal sphincter mechanism are removed, the colostomy is permanent; however, if the sphincter mechanism is preserved, there is the potential for ostomy reversal. As with ileostomies, colostomies may be created in a loop or end fashion.

Temporary — A temporary "diverting" colostomy can be performed on an emergency basis to decompress an obstructed or perforated distal colon. A temporary colostomy may also be performed electively to facilitate healing of perianal sepsis (ie, fistulas or perineal wounds) or acute inflammatory process distal to the colostomy. Diverting colostomy may also be used to protect a low-lying colorectal anastomosis when delayed healing is anticipated (eg, postradiation) or the risk of anastomotic complications is high. Still, the preferred type of ostomy for this purpose is a "diverting" loop ileostomy given the relative ease of reversal compared with loop colostomy [5,20,21]. (See 'Diverting loop ileostomy' above.)

Colostomy for decompression — Patients with obstructing lesions of the colon may require emergency decompression to prevent intestinal perforation [22]. (See "Large bowel obstruction", section on 'Management of acute large bowel obstruction'.)

Colostomy provides a mechanism for evacuating fecal contents and also permits access to the obstructed bowel for diagnostic colonoscopy. In addition, a colostomy allows the dilated proximal bowel to regain normal caliber, which may facilitate subsequent intestinal anastomosis.

The most commonly performed decompressing colostomies are:

●Transverse loop colostomy – A loop of transverse colon is brought out through the abdominal wall, opened, and sutured to the dermis and stabilized with a rod or bridge until the bowel granulates to the abdominal wall.

●Cecostomy – The anterior wall of the cecum is opened and sutured to an opening in the abdominal wall.

●Sigmoid loop colostomy – A sigmoid loop colostomy is similar to the transverse loop colostomy and useful for patients with a redundant sigmoid colon and an obstructive rectal or anal cancer.

Decompressing colostomies are typically temporary. A staged approach to colon resection using a decompressing colostomy is often beneficial by reducing the risk of abdominal contamination and enabling definitive management of the underlying disease process to be performed electively rather than urgently. However, the need for an additional separate procedure to reverse the ostomy and, for some patients, problems related to self-care and maintenance of a secure pouching system are particular disadvantages to the creation of a colostomy and should not be overlooked [23].

Colostomy for fecal diversion — Loop ileostomy is a safer diversion with lower morbidity rates in situations where temporary diversion is required, such that diverting colostomy is being used less frequently [5-9]. (See 'Diverting loop ileostomy' above.)

Nevertheless, colostomy can be used to divert the fecal stream proximal to a fistulous tract (entero-vaginal, -vesicular or -urethra), an area of inflammation (proctitis or perianal sepsis), unresectable distal malignancy, or for protection of a distal anastomosis. In these settings, fecal diversion promotes quiescence of the disease process or healing of the anastomotic site. A colostomy can also be used in the setting of fecal incontinence in patients who have failed conservative management or who are not candidates for other surgical intervention.

Approaches to temporary diverting colostomy include the following:

●A loop colostomy is created by bringing a loop of colon up to the abdominal wall. The ostomy is created with a proximal end (afferent limb) that allows fecal diversion and a distal end that allows venting of the distal length of bowel (efferent limb), thereby minimizing the potential for perforation of the distal colon or rectum (in the setting of obstruction).

●An end-loop colostomy is created by exteriorizing a loop of colon, dividing the colon with a linear stapler, allowing the distal end to recess into the subcutaneous space, and using the proximal end to create the stoma. These end-loop colostomies are generally created when there is concern for ischemia of the bowel segment due to a foreshortened mesentery; the loop allows for additional length over an end stoma. If one is concerned for persistent distal obstruction, the surgeon may mature the distal limb adjacent to the proximal limb as a mucous fistula.

●A double barrel stoma is created by transecting the bowel and bringing each end up to the abdominal wall as separate stomas (eg, a proximal functional colostomy and a distal mucous fistula), usually adjacent to one another.

●A Hartmann's procedure brings the proximal end of the transected bowel up to the abdominal wall as an end-colostomy, while the distal end is oversewn or stapled and left in the abdominal cavity as a nonfunctional stump (usually tagged with a suture to facilitate future identification). The distal end can also be secured in place adjacent to the colostomy as a mucous fistula in the subcutaneous tissue but not matured out to the skin. Creation of the mucus fistula is performed when there is a high likelihood of breakdown of the defunctionalized stump, which can lead to abdominal sepsis.

Permanent — When permanent fecal diversion is required, a colostomy is often beneficial due to a decreased risk for dehydration and electrolyte abnormalities associated with permanent ileostomy, which is particularly beneficial in older patients. (See 'End-ileostomy' above.)

Clinical settings that may warrant construction of a permanent colostomy include:

●Abdominal perineal resection for rectal cancer

●Fecal incontinence related to anal outlet dysfunction or perianal sepsis

PREPARATION AND COUNSELING — Preoperative preparation prior to planned ostomy creation includes stoma site selection, emotional support, and patient education, as well as early planning for subsequent discharge, ongoing rehabilitation care for the patient and loved ones, and outpatient follow-up [24].

Patients who require an ostomy for fecal diversion often experience physical, psychological, and emotional stress related to misconceptions and fears regarding social acceptance, sexuality, and economic burden [25]. To allay these fears, preoperative education, counseling, and ostomy site selection should be undertaken, whenever possible, from a skilled ostomy nurse specialist (enterostomal therapy nurse, wound ostomy continence nurse).

Patient education and counseling — Preoperative counseling by an ostomy nurse specialist improves postoperative quality of life by helping patients psychologically adapt to the significant lifestyle changes associated with living with a stoma. Retrospective studies have demonstrated that involvement of an ostomy nurse specialist has a significant impact on long-term positive outcomes and reduced complication rates, as does involvement in ostomy support groups such as the United Ostomy Association of America [19,26-30].

In addition to improved overall quality of life, preoperative counseling is associated with decreased stoma-related postoperative complications [27,31], improved postoperative patient stoma proficiency, and earlier discharge from the hospital [32-34].

Site selection and marking — In retrospective reviews, proper site selection is essential for minimizing postoperative complications and achieving a good postoperative quality of life [27,35,36]. A poor site selection is more likely in patients undergoing emergency surgery compared with elective surgery [31,35,37,38]. A multicenter retrospective review of 748 patients found that those who had preoperative stoma site markings were significantly less likely to develop later problems and complications compared with those without preoperative stoma site markings (23 versus 46 percent) [35]. Typically, the site is selected preoperatively with collaboration of the enterostomal nurse, the surgeon, and the patient. In the absence of an ostomy nurse specialist, such as with urgent surgery, particularly during off hours, preoperative stoma site selection and patient counseling by an experienced surgeon is also appropriate. Follow-up counseling with an ostomy nurse specialist in the postoperative period is particularly important and recommended since postoperative stomal complications are more common when constructed on an urgent basis [31,37-39]. (See "Ileostomy or colostomy care and complications", section on 'Ostomy complications'.)

Factors to consider preoperatively with respect to stoma placement include abdominal wall contour (sitting and standing), prior abdominal incisions, bony prominences, occupation, clothing style (belt line), disability, and any physical limitations. Suboptimal stoma placement increases the risk of complications and worsens quality of life. (See "Ileostomy or colostomy care and complications", section on 'Ostomy complications'.)

To optimize pouch adherence and independence in self-care, the following general principles should be followed when identifying the ostomy site:

●The ostomy should lie on either side of the abdominal midline, just lateral and inferior to the umbilicus. Often, a site is selected that overlays the rectus abdominis muscle, which can provide additional support and stability for the stoma. (See 'Create the aperture' below.)

●The patient must be able to visualize the stoma and access it without difficulty. In patients with obesity, the stoma often must be located higher on the abdominal wall (above the umbilicus), where the stoma may be more visible to the patient and the abdominal wall is less thick.

●The ostomy placement ideally must be at least 5 cm from all folds, creases, previous incisions, belt line, umbilicus, and bony prominences because these can interfere with appliance adherence. This is particularly important in patients with obesity or those who have had prior abdominal surgery.

●In the setting of an urgent procedure without preoperative stoma site markings, a reasonable location is two-thirds the way along the line from the anterior superior iliac spine and the umbilicus.

ROLE OF LAPAROSCOPY — The laparoscopic approach is a safe and effective alternative to a laparotomy for creating loop ostomies, particularly loop ileostomy or loop sigmoid colostomy, since these do not typically require significant bowel mobilization [40-45]. Laparoscopy is our preferred approach when the principle indication for the procedure is the need for a defunctioning stoma (eg, relief of a bowel obstruction), provided the likelihood of adhesions is low (absence of multiple previous surgeries).

Advantages of the laparoscopic approach are that it provides an excellent view of the abdominal cavity and minimizes the risks and complications of an open procedure. A prospective study included 19 patients undergoing a laparoscopic approach for constructing a stoma and compared their results with historic controls of 23 patients undergoing a laparotomy [43]. The laparoscopic approach was associated with significantly lower postoperative morphine requirements (48 versus 90 mg), earlier time to return of bowel function (2.2 versus 3.6 days), earlier tolerance of solid diet (3.6 versus 5.5 days), and fewer postoperative complications (1 of 19 versus 4 of 23 patients). Conversion rates from a laparoscopy to a laparotomy range from 0 to 16 percent and are mainly related to adhesions from previous surgeries [43-45].

Several techniques have been described, varying in location and number of port sites. The author prefers a three-port technique for a loop or end ileostomy. Access to the peritoneal cavity is achieved using standard techniques. (See "Abdominal access techniques used in laparoscopic surgery".)

A 12 mm port is placed at the preselected stoma site. The entire abdominal cavity is examined visually. If feasibility is confirmed, two additional 5 mm ports are placed in the suprapubic and left iliac fossa, two fingerbreadths above and two fingerbreadths medial to the anterior superior iliac spine. If adhesions limit visibility and accessibility to the segment of bowel to be used for the ostomy, the procedure can be converted to a laparotomy. A similar approach is used for sigmoid loop or end colostomy, but the lateral working ports are positioned in a mirror image to those placed for a loop ileostomy.

Single-port techniques have also been described. Abdominal access is obtained at the previously determined site, and pneumoperitoneum is established. Once the anatomy has been confirmed, the selected loop of intestines is brought out through the aperture. Careful attention is taken to maintain the correct orientation as confirming the orientation is quite difficult in single-port surgery. As such, single-incision surgery should be reserved for more advanced laparoscopists. (See "Abdominal access techniques used in laparoscopic surgery".)

When creating an end or loop sigmoid ostomy laparoscopically, the bowel is mobilized in the lateral to medial direction, extending from the rectosigmoid to the mid-descending colon. Mobilization of the mesentery is generally not necessary, except in the presence of abdominal or pelvic adhesions. The aperture is created and matured to the skin as described below. Prior to maturing the stoma, the proper orientation of the bowel must be verified. (See 'Ostomy construction' below.)

OSTOMY CONSTRUCTION — A stoma is essentially an anastomosis of the intestine to the anterior abdominal wall skin [1]; however, construction of stoma, particularly in the presence of a thick abdominal wall and short, thick mesentery, can be challenging.

Mobilize the bowel — Selection of the appropriate intestinal segment is determined by several factors, including age, comorbidities, body habitus, and whether the fecal diversion will be permanent or temporary. Construction of an ostomy should always be performed using a segment of healthy, well-vascularized bowel. Expected difficulties arise in patients with severe obesity or extensive adhesions.

The following maneuvers will help mobilize sufficient large bowel, as needed, to ensure the creation of a properly protruding, well-vascularized, tension-free approximation to the abdominal wall and minimize the risk of complications:

●Peritoneal attachments should be adequately mobilized, including:

•Completely mobilize the splenic flexure when creating a descending colostomy

•Transect the medial peritoneal attachments at the base of the colon mesentery

•Transect the inferior mesenteric artery proximal to the left colonic arterial origin to decrease tethering effect

•If necessary to avoid tension or risk of retraction, create peritoneal windows over the colonic mesentery just below the stoma

●Trim thickened colonic mesentery and excess tenia epiploicae (fat appendages) to ease the passage of the intestine through the abdominal wall, while preserving the marginal artery

Create the aperture — The appropriate size of the aperture in the abdominal wall can be difficult to judge. Large apertures increase the risk for parastomal hernia, while small apertures can result in ischemia, stricture, stomal outlet obstruction strictures, or stomal necrosis. The skin and fascial openings should be large enough to pull the selected intestine through the abdominal wall without occluding the mesenteric vessels and intestinal lumen (figure 5). (See "Parastomal hernia".)

The skin overlying the previously determined ostomy site is excised using a full-thickness circular incision. The circular portion of subcutaneous tissue is dissected using knife or electrocautery and the anterior rectus fascia cleared. A 2 cm vertical or cruciate incision ("plus sign") is made in the anterior rectus fascia. A randomized trial found no difference in one-year parastomal hernia rate between cruciate incision, circular incision, or mesh reinforcement [46]. The author prefers a 2 cm vertical incision that minimizes fascial disruption and allows two fingerbreadths to pass snugly for both ileostomy and colostomy. Often, a colostomy will require a larger trephine to allow easy passage of the intestine through the abdominal wall, decrease tension, avoid ischemia, and minimize venous congestion (figure 6).

In the standard technique of stoma creation, the trephine typically traverses one of the rectus abdominis muscles, which in theory provides additional support and stability for the stoma. An alternative method of stoma creation, lateral rectus abdominis positioned stoma (LRAPS), places the trephine lateral to one of the rectus abdominis muscles through transverse incisions in both the anterior and posterior rectus sheath [47]. Despite good results reported by the inventor in a single-center case series [47], LRAPS did not lower the parastomal hernia rate compared with the standard trans-rectus technique in a subsequent small randomized trial [48] and a Cochrane review that included this trial and 10 observational studies [49].

Prophylactic mesh — Since 2012, multiple randomized trials have been published on the use of prophylactic mesh when constructing a permanent end colostomy during elective surgery [50-55]. Placement of mesh at the time of stoma formation reduced the risk of parastomal hernia formation in some studies [53,54] but had no effect in others [55]. For patients undergoing construction of a permanent stoma, we suggest not routinely placing prophylactic mesh. (See "Prophylactic mesh for ventral incisional hernia prevention".)

●The largest randomized trial (STOMAMESH), a multicenter, double-blind trial involving 232 permanent end colostomies, found that a sublay mesh of lightweight polypropylene did not reduce the incidence of parastomal hernia at one year (clinical exam 30 percent no mesh versus 29 percent mesh; radiologic exam 34 versus 32 percent) or three years (clinical exam 37 percent no mesh versus 39 percent mesh; radiologic exam 45 versus 42 percent) [55,56].

Another multicenter randomized trial also reported that sublay placement of non-cross-linked porcine-derived acellular dermal matrix at the time of stoma construction did not reduce the incidence of parastomal hernias at two years (12.2 percent mesh versus 13.2 percent control) [57]. Of note, this study included a high percentage of ileostomies, which historically have a low incidence of parastomal hernia herniation.

●By contrast, a similar but smaller trial (PREVENT) published in 2016 showed that augmenting the abdominal wall with a retromuscular (sublay) lightweight polypropylene mesh reduced the parastomal hernia rate from 24.2 to 4.5 percent at one year, compared with the traditional formation of a colostomy, without affecting other patient outcomes (eg, infections) [53,54]. Compared with the STOMAMESH trial, which had a very similar design, the PREVENT trial lacked blinding in clinical assessment of the hernia and routine computed tomography follow-up.

Several systematic reviews and meta-analyses of randomized trials also demonstrated that prophylactic use of mesh at the time of stoma formation reduces hernia formation [58-61], either in hernia incidence (12.5 percent mesh versus 53 percent no mesh) [58] or odds ratio (OR 0.24; 95% CI 0.10-0.58) [62].

Most studies describe an open approach and place a retromuscular mesh with a hole in the center of the prosthesis; a few other studies used a laparoscopic approach either with a keyhole mesh or a modified Sugarbaker technique [57,63]. (See "Parastomal hernia".)

In general, if mesh is used, prosthetic (synthetic) mesh is favored over biologic mesh, and securing a prosthetic mesh adjacent to the bowel also appears to be safe with overall low rates of complications [57,60]. (See 'Location of mesh' below and 'Type of mesh' below.)

Location of mesh — The effectiveness of using mesh for reducing the risk of a parastomal hernia may depend upon the location of mesh placement and possibly the type of mesh. Mesh is placed in a manner similar to the repair of parastomal hernia, but at the time of primary stoma formation. In order of preference, the mesh can be placed in a sublay, onlay, or intraperitoneal position (figure 7) [63-68]. (See "Parastomal hernia".)

Sublay — Sublay mesh is placed anterior to the posterior rectus sheath, which limits contact between mesh and bowel wall and potentially decreases the risk for mesh migration, which can occur with the onlay technique. The sublay technique is the most frequently used and our preferred approach. In three randomized trials, ostomy creation using prophylactic mesh in the sublay position was compared with no mesh [63,66,69]. Prophylactic mesh significantly reduced the risk of a parastomal hernia (range 0 to 22 versus 44 to 81 percent). There were no differences in the incidence of complications between the groups (eg, stomal infection, necrosis, stenosis).

To place sublay mesh during ostomy creation, after creating the aperture in the skin and subcutaneous tissue, the rectus muscle is split in the direction of its fibers and the posterior rectus sheath is incised. The plane is developed between the rectus muscle and the posterior rectus sheath (figure 8). A circular opening is made in the center of a 6 by 6 cm biologic mesh, large enough to accommodate the circumference of the bowel used for the ostomy. The mesh is placed into the subfascial plane and tacked into place using polydioxanone (eg, PDS) suture at the 12, 3, 6, and 9 o'clock positions to prevent displacement of the mesh during extraction of the intestine. The bowel is guided through the mesh and the aperture. The bowel can be tacked to the mesh without added morbidity, but this has not been shown to provide any added benefit and is not performed by the author. The ostomy is then matured by everting the full-thickness bowel and securing to the skin without tension as described below.

Onlay — The onlay technique places the mesh anterior to the rectus fascia, which avoids extensive dissection and minimizes additional operative time. In a prospective study of 24 patients undergoing ostomy creation using prophylactic polypropylene mesh in an onlay position, only two patients developed parastomal hernia with a median follow-up of 12 months [70]. No wound infections were reported, and two patients had minor complications requiring revision of the mesh placement.

Intraperitoneal — Placement of intra-abdominal mesh at the time of the construction of the ostomy is not commonly used for prophylactic mesh placement [68,71]. The technique brings the bowel out directly through a "keyhole" defect made in the mesh [71], or the mesh is placed over the loop of intestine after it has been brought through the abdominal wall, similar to that of the Sugarbaker technique for parastomal hernia repair (figure 9) [72]. (See "Parastomal hernia".)

Each of these techniques for intraperitoneal mesh placement avoids abdominal wall dissection and is feasible via laparoscopy. The main disadvantage is the potential for adhesion formation and intestinal obstruction [73,74]. In a prospective study of 24 patients with intraperitoneal mesh placed at construction of an ostomy, no parastomal hernias or infections were observed with a median follow-up period of 11 months [75]. However, follow-up was too short to determine the risk of long-term complications, such as obstruction.

Type of mesh — The optimal mesh for preventing parastomal hernia has not been clearly determined. Based on available data, prosthetic mesh is favored over biologic whenever possible. Because there are no high-quality data associating prosthetic mesh with increased risk of infection or other complications, the high cost of a biologic mesh is usually not justified in routine cases [53,62,65]. However, biologic mesh remains favored for use in contaminated fields and for patients with inflammatory bowel disease due to the high risk of reoperation [76,77]. When using a prosthetic mesh, it is the author's preference to use a wide/large pore mesh.

Each type of mesh is safe and associated with low rates of complications, such as infection, erosion, fistula, and stenosis [78-80]. Biologic mesh is a biocompatible alternative to synthetic prosthetic mesh and has comparable tensile strength; acellular dermal matrix (ADM), which becomes vascularized and remodeled into autologous tissue after implantation, may represent the best alternative to prosthetic mesh [63,80].

The various types of mesh that are available for surgical reconstruction, including synthetic and biologic substitutes, are reviewed in detail elsewhere. (See "Reconstructive materials used in surgery: Classification and host response", section on 'Types of materials'.)

Ostomy construction and maturation

End-ostomy — Once the aperture is created and prophylactic mesh placed (if elected), the segment of intestine is advanced through the abdominal wall (and mesh). (See 'Prophylactic mesh' above.)

All remaining abdominal incisions should then be closed to prevent possible spillage into the abdomen while maturing the ostomy.

An ileostomy should protrude at least 2 to 3 cm above the abdominal wall after Brooke's eversion to allow adequate output of its contents into the appliance (figure 2). By contrast, because of its more solid output, colostomies require only a 1 to 2 cm protrusion above the abdominal wall. It is our practice to construct at least a small amount of protrusion for the colostomy to assure adequate ostomy appliance placement and adherence.

To mature an end-ileostomy or colostomy:

●Deliver the end of the small bowel or colon through the abdominal wall (figure 10 and figure 11).

●Transect the staple line with electrocautery (figure 12 and figure 13).

●Place four absorbable stay sutures equidistant at 12, 3, 6, and 9 o'clock to attach the intestine to the abdominal wall trephine. Leave the sutures untied and tag the tails of the stay sutures with small clamps to aid in everting the intestine.

•When constructing an ileostomy, the suturing incorporates (figure 14) Brooke's eversion technique by including the full-thickness cut end of bowel, the seromuscular layer of the bowel wall approximately 3 cm proximal to the cut end, and then the dermis of the abdominal wall.

•When creating a colostomy, the suture includes (figure 15) the full thickness of the cut end of the colon and the dermis of the abdominal wall, although the seromuscular layer may also be included to ensure an adequate eversion of the stoma.

●Evert the intestine by gently pulling on the sutures, then tie in place. If eversion has not occurred with tying of the sutures, gently push on the seromuscular layer in between sutures to complete the process.

●Place one to two additional sutures in between the originally placed stay sutures, approximating the full-thickness distal bowel with the dermis.

●Place a clear ostomy appliance over the stoma. A clear appliance allows for visual inspection at the bedside postoperatively.

Loop ostomy — A loop ileostomy or loop colostomy can be performed with a defunctionalized distal limb or as a double barrel ostomy. The resulting ostomies of the double barrel ostomy are larger and more cumbersome to manage (eg, leakage) compared with a loop ostomy that has a compressed distal limb; however, the double barrel ostomy may be preferable in urgent settings as some surgeons find it takes less time to perform.

●The defunctionalized distal limb (figure 16) is an efficient stoma with the proximal functioning limb occupying the majority of the abdominal wall aperture. This is the author's preference for both a loop ileostomy and loop colostomy. (See 'Loop ostomy with a defunctionalized distal limb' below.)

●A double barrel ostomy (figure 17) can be constructed as a loop ostomy with both limbs everted and the back wall intact or as completely divided proximal and distal limbs that are brought together through the abdominal wall trephine. (See 'Double barrel ostomy' below.)

Loop ostomy with a defunctionalized distal limb — Once the aperture is created and prophylactic mesh placed (if elected), the segment of intestine is advanced through the abdominal wall (and mesh) with the aid of a Penrose drain placed through a small mesenteric defect (figure 18). (See 'Prophylactic mesh' above.)

The abdominal incision should then be closed to prevent possible spillage into the abdomen while maturing the ostomy.

To mature a loop ostomy (ileostomy or colostomy) with a defunctionalized distal limb:

●If the stoma is advanced through the aperture and rests comfortably on the abdominal wall without retraction or tension, the Penrose drain can be removed and stoma constructed. If stoma is difficult to advance through the trephine, additional security may be desired to help support the stoma above the abdominal wall. In this scenario, you may replace the Penrose drain with a 14 Fr red rubber catheter. The red rubber catheter is shaped in a large loop and secured to itself with 0 silk ties (figure 19).

●Transect 80 percent of the circumference of the bowel wall with electrocautery, beginning on the antimesenteric wall at the distalmost portion of the descending or nonfunctional limb (figure 20 and figure 21).

●Secure the distal descending limb to the abdominal wall with three absorbable sutures, tacking the full-thickness bowel to the dermis, without everting the distal portion of the loop ostomy (figure 22).

●Evert and secure the proximal functional limb by suturing the full-thickness bowel wall to the seromuscular layer 3 cm proximal to the partially transected end with the dermis of the abdominal wall opening (figure 22).

•Four absorbable stay sutures are placed on the antimesenteric border of the bowel at the junction of the proximal and distal limbs of the stoma and secured (not tied) with small clamps.

•The functional proximal limb should occupy 80 percent of the aperture site.

•Tie the sutures in place to evert the proximal limb.

●Place one to two additional sutures in between the originally placed stay sutures, approximating the full-thickness distal bowel with the dermis.

●Place a clear ostomy appliance over the stoma. A clear appliance allows for visual inspection at the bedside postoperatively. The catheter or rod can be removed approximately three to five days after the procedure.

Double barrel ostomy — Once the aperture is created and prophylactic mesh placed (if elected), the segment of intestine is advanced through the abdominal wall (and mesh) with the aid of a Penrose drain (figure 18). (See 'Prophylactic mesh' above.)

The abdominal incision should then be closed to prevent possible spillage into the abdomen while maturing the ostomy.

To mature a double barrel ostomy with an intact back wall:

●A longitudinal or circumferential incision can be used to create the opening in the stoma at the apex of the selected limb, with the back wall remaining intact (figure 23).

●Both the proximal and distal limbs are everted (figure 17).

●The bowel is secured to the abdominal wall as described above. (See 'Loop ostomy with a defunctionalized distal limb' above.)

●A clear ostomy appliance is placed over the stoma. A clear appliance allows for visual inspection at the bedside postoperatively. The catheter or rod is removed approximately 7 to 10 days after the procedure.

To mature a double barrel ostomy with a divided back wall:

●The bowel is divided with a stapler, and the functioning proximal limb and decompressed distal limb are brought through the abdominal wall (figure 24). One abdominal wall aperture is created for the stoma when no bowel is resected (eg, emergency decompression of an obstruction), whereas the proximal and distal limbs are brought through separate apertures if bowel has been resected between the two ends.

●The ends are matured and secured to the abdominal wall as described above for end colostomy. (See 'End-ostomy' above.)

●A clear ostomy appliance is placed over the stoma. A clear appliance allows for visual inspection at the bedside postoperatively.

Delayed stoma maturation — Timing of maturation in the urgent clinical setting depends upon the appearance of the bowel and the condition of the patient. Maturation should be performed within seven days postoperatively, provided the patient has stabilized, the intestine is viable with adequate blood flow, and edema has resolved enough to properly secure the stoma to the abdominal wall.

Other sites of fixation — Stomal fixation to the fascia (or to the mesh) is optional. Additional fixation has not been shown to reduce the risk of parastomal herniation or prolapse [81,82]. Thus, we do not provide additional fixation beyond normal maturation of the stoma to the skin. (See 'Prophylactic mesh' above and "Parastomal hernia".)

One approach for fixing the stoma to the fascia is to place absorbable sutures transabdominally from the posterior fascia or peritoneum to the seromuscular layer of the bowel, effectively fixing the limb to the abdominal wall.

Suturing the ileal or colonic mesentery to the lateral abdominal wall to close the lateral sulcus has also been suggested as a means for preventing the rare complication of a volvulus around the stoma limb [83,84]. Given the rare occurrence of small bowel obstruction related to a volvulus after stoma construction [38], we do not perform this type of fixation either.

Placing of the stoma through the extraperitoneal route has been hypothesized to reduce the risk of herniation. An aperture is created in a similar fashion; however, a tunnel is made through the preperitoneal space to allow sufficient room for the intended bowel to be brought up and create the stoma. This technique has been reported in both open and laparoscopic techniques [85]. However, a Cochrane database meta-analysis of 10 retrospective studies and one trial found the effect of placing the stoma through the extraperitoneal route on parastomal hernia or stomal herniation to be uncertain [49].

OSTOMY REVERSAL

Colostomy closure — For temporary end colostomy, such as created in a Hartmann's procedure, closure is delayed until complete resolution of the underlying condition has occurred, the patient's health status is fully recovered to baseline, and inflammation has subsided with softening of adhesions, which can take three to six months or more. Colostomy reversal will often require takedown of residual adhesions that prevent proper mobilization of the colostomy from the abdominal wall. Laparoscopy can be used to free difficult adhesions prior to colostomy takedown; however, exploratory laparotomy may be needed.

For diverting loop colostomy, closure of the colostomy may be performed within six to eight weeks if diagnostic studies indicate that the need for diversion no longer exists (eg, if the distal anastomosis is well healed). Closure of a loop colostomy can be performed locally by freeing the colostomy circumferentially from the abdominal wall. The proximal and distal limbs are then aligned for a side-to-side functional end-to-end stapled anastomosis. The common channel between the two limbs is created with the use of a linear GIA stapler. The end-colostomy is then closed with either a second load of a GIA or TA stapler. The anastomosis is then placed within the peritoneal cavity and the fascia is closed. Alternatively, if a stapled anastomosis is not feasible, then a handsewn anastomosis may be performed.

Ileostomy closure — When a loop ileostomy is performed, it is usually closed between eight weeks and three months following the initial procedure, once the anastomosis is well healed.

A systematic review identified six trials that have compared early with delayed ileostomy closure. Early closure was defined as within 8 to 17 days of ileostomy creation by five trials and as within one month by the other trial [86]. Late closure was defined as between 57 and 278 days after ileostomy creation. Compared with late closure, early closure of ileostomy required less operative time and reduced the incidence of small bowel obstruction/postoperative ileus but increased the incidence of surgical site infection and the length of hospital stay. Otherwise, there was no difference in morbidity, reoperation, or anastomotic leak rate.

Closure is performed in a similar manner to loop colostomy as described above. The stoma is freed for the abdominal wall and extracted through the trephine. Once completely free of adhesions, the two limbs are aligned for a side-to-side functional end-to-end stapled anastomosis.

Hernia prevention — Reversal of an ostomy can result in a high rate of incisional hernia at the ostomy site. A systematic review and meta-analysis estimated that about one in three patients will develop a hernia after stoma closure, and half of the hernias will require surgical repair [87].

In a multicenter trial (ROCSS) of 394 patients, reinforcing the abdominal wall with a biologic mesh placed intraperitoneally at the time of stoma closure reduced clinical detectable incisional hernias at two years (12 versus 20 percent, p = 0.012) and radiologically detectable hernias at one year (9 versus 21 percent, p <0.001) without increasing complication rates compared with standard suture closure [88].

Two other randomized trials are ongoing, both of which study the efficacy of synthetic mesh placed in the retrorectus position (NCT02576184; NCT03750942).

A 2019 systematic review and meta-analysis supported the use of prophylactic mesh reinforcement at the site of stoma. Despite longer operative times, the placement of mesh was associated with lower risk of surgical site incisional hernia (7.8 versus 18.1 percent) and reoperations (8.1 versus 12.1 percent). There was no difference in other outcomes such seroma formation, anastomotic leakage, or length of stay. A preferred mesh type was not identified [89].

Overall, the evidence is growing for either synthetic or biologic mesh being placed at the time of stoma reversal without incurring additional risks such as mesh infection. However, caution is warranted regarding routine prophylactic mesh placement, given that high-risk patients with large parastomal hernias were excluded from the randomized trials and that the optimal position of the mesh (eg, intraperitoneal versus retrorectus) remains unclear.

The author of this topic performs a small component separation when reversing an ostomy in patients at high risk for incisional hernia. Relaxing the external oblique fascia reduces the tension at the ostomy closure site, which may reduce the incisional hernia risk while avoiding the use of mesh.

COMPLICATIONS — The complications of ostomy construction and later complications related to fecal diversion are discussed in detail separately. Parastomal hernia and its management are reviewed separately. (See "Ileostomy or colostomy care and complications", section on 'Ostomy complications' and "Parastomal hernia".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Parastomal hernia".)

SUMMARY AND RECOMMENDATIONS

●Types of fecal diversion – An ostomy is a purposeful anastomosis between a segment of the gastrointestinal tract and the skin of the anterior abdominal wall. Fecal diversions are commonly classified according to the segment of the bowel used to create the ostomy (eg, sigmoid, colon, ileum) and the manner of surgical construction (eg, loop, end, reservoir). Fecal diversion by creation of an ostomy (ileostomy, colostomy) is indicated when restoration of intestinal continuity is contraindicated or not immediately feasible given the patient's clinical condition. (See 'Fecal diversions' above.)

●Preoperative preparation – Preoperative evaluation includes counseling and site selection. Prior to elective procedures, preoperative siting of the stoma by an enterostomal nurse is preferred, rather than intraoperative site selection. In the absence of an enterostomal nurse, such as with urgent surgery, particularly during off hours, preoperative stoma site selection and patient counseling by an experienced surgeon is also appropriate, but we refer the patient for counseling with an ostomy nurse specialist in the postoperative period. (See 'Site selection and marking' above and 'Preparation and counseling' above.)

●Stoma site selection – The stoma should be located to either side of the abdominal midline, just lateral and inferior to the umbilicus. The patient must be able to see the stoma and access it without difficulty. The ostomy placement must be at least 5 cm from all folds, creases, previous incisions, belt line, umbilicus, and bony prominences for optimal appliance adherence. (See 'Site selection and marking' above.)

●Laparoscopic approach – For patients undergoing construction of a defunctioning stoma (eg, relief of a bowel obstruction) as the sole indication and who have not undergone multiple prior abdominal surgeries, we suggest a laparoscopic approach, rather than an open abdominal approach (Grade 2C). (See 'Role of laparoscopy' above.)

●Temporary diversion – For patients requiring temporary loop ostomy for the sole purpose of diversion, we use a diverting loop ileostomy, rather than a diverting loop colostomy. Reversal of a loop ileostomy is easier compared with loop colostomy. However, when permanent or immediate fecal diversion is required, we use a colostomy when feasible, rather than an ileostomy, particularly in older patients. Colostomy has less risk for dehydration and electrolyte abnormalities.

●Prophylactic mesh placement – For patients undergoing construction of a permanent stoma, we do not suggest routinely placing prophylactic mesh (Grade 2C). Placement of mesh at the time of stoma formation remains controversial and has been associated with a reduction in the incidence of parastomal hernia formation in some studies but not in others. When mesh placement is elected, prosthetic meshes are generally safe and preferred; biologic meshes may be preferred in contaminated cases or inflammatory bowel disease patients (for a higher risk of reoperation). Most meshes are placed in the retromuscular (sublay) position. (See 'Prophylactic mesh' above and "Parastomal hernia".)

●Ostomy reversal – Reversal of temporary ostomy is delayed until the underlying condition has resolved, the patient has recovered to baseline status, and inflammation has subsided with softening of adhesions, which can take up to three months. Ostomy closure can generally be performed locally by freeing the stoma circumferentially from the abdominal wall and using a stapler to create a side-to-side functional end-to-end anastomosis. If a stapled anastomosis is not feasible, then a handsewn anastomosis may be performed. (See 'Ostomy reversal' above.)