INTRODUCTION — Parastomal hernia is the most frequent complication following the construction of a colostomy or an ileostomy, occurring in up to 50 percent of patients. A parastomal hernia is a type of incisional hernia that allows protrusion of abdominal contents through the abdominal wall defect created during ostomy formation (image 1). It should be recognized that, unlike a hernia development in a surgical incision for which the fundamental problem is healing between tissues that have been approximated, ostomy creation introduces an abdominal wall defect, the trephine, for which no healing is expected. A parastomal hernia forms as the trephine is continually stretched by the forces tangential to its circumference [1].
The construction of an ostomy and the management of patients with an ileostomy or colostomy are reviewed separately. (See "Overview of surgical ostomy for fecal diversion" and "Ileostomy or colostomy care and complications".)
EPIDEMIOLOGY AND RISK FACTORS — The reported incidence of parastomal hernia varies widely and is related to the type of ostomy constructed, the duration of follow-up after ostomy construction, and the definition used to identify parastomal hernia. The incidence of parastomal hernia is reported as ranging from 0 to 50 percent, depending upon the type of ostomy [2-12]. One review found the following rates of parastomal hernia formation [12]:
●End ileostomy – 1.8 to 28.3 percent
●End colostomy – 4.0 to 48.1 percent
●Loop ileostomy – 0 to 6.2 percent
●Loop colostomy – 0 to 30.8 percent
The lower rate for loop ostomy is related to the frequently temporary nature of most of these stomas and the short duration of follow-up. By contrast, the Swedish National Colorectal Cancer Registry and National Patient Register were used to identify colorectal cancer patients with a permanent colostomy. In over 6000 patients followed between 2007 and 2013, the cumulative incidence of patients either diagnosed with or surgically treated for a parastomal hernia was 7.7 percent [13]. The only identified risk factor for parastomal hernia development in this cohort was a body mass index (BMI) >30 kg/m2.
The incidence of parastomal hernia is also influenced by the means of construction. The incidence is lower for isolated laparoscopic ostomy construction (0 to 6.7 percent) compared with trephine single-incision ostomy construction (6.7 to 12 percent), and even higher when ostomy construction is combined with other procedures or open abdominal exploration. The placement of prophylactic mesh at the time of ostomy construction is associated with a significant decline in parastomal hernia formation (0 to 8.3 percent) [14-18]. (See "Overview of surgical ostomy for fecal diversion".)
Risk factors — Factors that increase the risk of parastomal hernia can be regarded as predominantly patient specific or technique specific.
Patient-specific factors include advanced age, wound infection, chronic or recurrent increases in intra-abdominal pressure, chronic obstructive pulmonary disease, obesity, abdominal wall strength, weight gain after ostomy construction, malnutrition, glucocorticoids, immunosuppression, malignancy, and inflammatory bowel disease [6,12,19-21]. Among these, obesity, defined as waist circumference >100 cm or BMI >30 kg/m2, is best supported by clinical evidence [6,21].
Technical factors that might influence the risk of parastomal hernia formation include emergency stoma placement and surgical technique for ostomy construction (open, laparoscopic). The diameter of the trephine in the abdominal wall fascia may be particularly important. An analysis of the forces acting upon the trephine that cause dilatation, and thus a hernia, revealed that the larger the trephine radius, the greater the tangential force pulling the trephine apart [1]. This physical analysis supports the clinical findings that parastomal hernia is less common following an ileostomy compared with colostomy and end stoma compared with loop stoma [22]. One study evaluated patients with permanent colostomies and found that at a mean follow-up of 26 months, no patient with an abdominal wall diameter ≤25 mm developed a parastomal hernia, which supports the concept that a smaller trephine is less likely to lead to parastomal hernia [23].
CLINICAL FEATURES — Most parastomal hernias occur within the first two years of construction, and studies with longer follow-up report higher parastomal hernia rates [7,20,24]. As with other types of abdominal wall hernias, patients typically present with a bulge at the stoma site (picture 1) or adjacent to it, with or without pain. A minor degree of parastomal abdominal wall weakness may be present in many patients, but this does not represent a true hernia [22]. (See "Overview of abdominal wall hernias in adults".)
Pain that does manifest can be mild abdominal discomfort, back pain, intermittent cramping, or more severe pain. In a French study of 782 patients, 25 percent developed parastomal hernia, of whom 76 percent had symptoms; however, only one-half of these patients had symptoms that were sufficiently bothersome to warrant repair [20]. The main complaints were pain occurring in 35 percent and difficulties in fitting a stomal appliance with leakage in 28 percent. Pain might also be due to peristomal skin irritation/breakdown related to stoma appliance leakage because of poor appliance fit related to the hernia. Peristomal pressure ulcers may develop as patients try to compensate for poor appliance fit by increasing appliance convexity or use belts to hold the appliance in place.
Patients with incarcerated or strangulated bowel within the hernia sac can have symptoms of bowel obstruction with nausea, vomiting, severe abdominal pain, and obstipation. Patients will frequently report significant "hardness" and pain at the site of the hernia if that is the site of the obstruction. (See 'Acute complications' below and "Etiologies, clinical manifestations, and diagnosis of mechanical small bowel obstruction in adults", section on 'Clinical presentations'.)
After removal of the appliance, the patient should be examined in the standing position and asked to perform the Valsalva maneuver. The peristomal skin needs to be evaluated for evidence of injury reflecting leakage or excessive appliance contact pressure. The extent of the hernia defect can be assessed by examining the paracolostomy or para-ileostomy tissue [12]. It is important to determine if the hernia sac content can be reduced. A digital examination of the stoma might provide further information if there are concerns about the abdominal wall or the hernia defect contributing to stoma dysfunction.
CLASSIFICATION — Several classifications for parastomal hernia have been proposed, but none are universally accepted [25-28]. Although these classification schemes may be useful in research and for academic discussions, in clinical practice there is little added value since management is based upon the symptoms induced by the hernia. These different types of hernia basically are treated in the same manner.
One of these classifications separates parastomal hernia into four subgroups based on the location of the hernia sac, which can contain bowel or omentum, but practically speaking, differences in hernia location and composition may be difficult to appreciate on physical examination (figure 1) [26]:
●Interstitial – The herniation extrudes alongside the bowel for the stoma, then burrows into one of the intermuscular planes.
●Subcutaneous (most common type) – The herniation extrudes from the abdomen alongside the bowel for the stoma and bulges into the subcutaneous fat alongside the stoma.
●Intrastomal – The herniation extrudes from the abdomen alongside the bowel for the stoma and enters the plane between the emerging and the everted part of the bowel. It usually occurs in the spout type of stoma, such as an ileostomy.
●Peristomal – The stomal bowel is prolapsed, and loops of bowel and/or omentum enter the hernia space produced between the layers of the prolapsed bowel.
A radiologic classification scheme using findings from cross-sectional imaging has also been developed [29]. This scheme distinguishes between possible contents of the hernia sac, including omentum, the loop of bowel forming the ostomy, and other loops of bowel not forming the ostomy.
DIAGNOSIS — A diagnosis of parastomal hernia is primarily clinical and can usually be made by history and physical examination of stoma. Patients with classic symptoms of a parastomal hernia and a negative examination of the abdominal wall and stoma generally do not require any imaging.
However, patients with obstructive symptoms should undergo further imaging studies, preferably a computed tomography (CT) of the abdomen to exclude other pathologies that could mimic or complicate a parastomal hernia. Ultrasound can only define the extent and degree of small para-ostomy hernias.
Differential diagnosis — For patients with abdominal complaints and a stoma, few entities would be confused for parastomal hernia. However, if the stoma is close to a midline incision, clinical findings may be due to an incisional hernia rather than related to the stoma. For patients with obstructive symptoms (nausea, vomiting, abdominal distention, obstipation) for whom examination of the stoma cannot account for the degree of symptoms, abdominal CT is warranted to identify the severity and location of the obstruction, which may not be related to the stoma (image 1), though a negative CT scan does not exclude a parastomal hernia (as it might only be present when the patient is upright). (See "Etiologies, clinical manifestations, and diagnosis of mechanical small bowel obstruction in adults", section on 'Diagnosis'.)
MANAGEMENT — Most patients with a parastomal hernia do not have symptoms that are sufficiently bothersome to warrant repair. For patients with no or only mild symptoms, we suggest conservative management with measures to improve patient comfort and ostomy functioning. Surgical repair is generally avoided due to the propensity for parastomal hernia to recur. (See 'Recurrence' below and 'Recurrent parastomal hernia repair' below.)
Patients who are being conservatively managed should be educated about signs and symptoms of bowel obstruction and bowel strangulation/infarction and should be instructed to seek medical attention if such symptoms occur to avoid delays in diagnosis, which can be life-threatening. Patients can call their surgeon or primary care provider or go to the nearest emergency room. (See "Etiologies, clinical manifestations, and diagnosis of mechanical small bowel obstruction in adults", section on 'Acute small bowel obstruction'.)
Stoma care — Patients without indications for surgery can be managed with a stoma belt (ostomy binder) [12]. A stoma belt is designed to provide stability around the stoma site to minimize bulging at the skin level. The main goal is not to reduce the hernia but to help fix the appliance in a stable position and lessen shearing, which causes the ostomy appliance to leak. When a stoma belt is appropriately sized by a wound/ostomy nurse, there are few, if any, complications. Issues related to ostomy care, including methods of limiting ostomy leakage and peristomal skin breakdown, ostomy trauma, and abdominal distention from excessive gas, are discussed in detail elsewhere. (See "Ileostomy or colostomy care and complications".)
Indications for hernia repair — Surgical repair is indicated for patients who develop acute parastomal hernia complications and for those with chronic symptoms that impair the quality of life. (See 'Clinical features' above.)
Acute complications — There is a low rate of life-threatening complications associated with parastomal hernia [12,22]. Urgent surgical repair is necessary for patients with a bowel obstruction resulting from an incarcerated hernia because of the risk for strangulation and bowel ischemia. (See "Management of small bowel obstruction in adults", section on 'Indications for immediate surgery'.)
Chronic bothersome symptoms — Patients with chronic symptoms that impair the quality of life are listed below, and patients may benefit from elective hernia repair.
●Stoma appliance dysfunction and leakage not responsive to conservative measures.
●Peristomal skin breakdown related to shear injury or ischemia from pressure on the thinned peristomal skin.
●Recurrent partial bowel obstruction.
●Chronic abdominal pain related to the parastomal hernia.
●Chronic back pain or hip pain related to the parastomal hernia [30].
●Psychological distress caused by any of the previous symptoms. The evaluation of psychological effects of parastomal hernia should be individualized. For some patients, the fear of stomal leakage in public is debilitating.
MESH FOR PARASTOMAL HERNIA REPAIR — Various types of mesh (polypropylene, expanded polytetrafluoroethylene [ePTFE], biologic) have been used in the repair of parastomal hernia. A systematic review of parastomal hernia repair techniques found no significant differences for one type of repair over the other with respect to mesh-related complications [31]. The risk of recurrent parastomal hernia was reduced when mesh was used compared with primary stoma repair [15-18,32-44]; however, parastomal hernia can still occur, but there are limited data regarding parastomal hernia that has occurred in spite of prophylactic mesh placement. (See 'Primary repair versus mesh repair' below.)
The use of a biologic substitute obviates the placement of prosthetic mesh material near the stoma [33], which is a contaminated site. Although data are limited regarding the use of biologic substitutes for repair of parastomal hernia [45-47], these should be considered in patients who are at high risk for prosthetic mesh complications, such as those with inflammatory bowel disease [48] or risk factors for wound infection. The expense of biologic substitutes, which can cost thousands of dollars per piece, probably cannot be justified for others. A systematic review identified four retrospective studies with a total of 57 patients, with all reports using a collagen-based biologic scaffold to reinforce or bridge the parastomal hernia defect [45]. Although wound complications occurred in 26 percent, there were no wound infections. Recurrence occurred in 16 percent of patients, a rate comparable to the failure rate of parastomal hernia repair using prosthetic mesh. (See 'Recurrence' below.)
SURGICAL APPROACH — There are many options for parastomal hernia repair using differing approaches (figure 2) [11,31,49-75]. Each has advantages and disadvantages. Parastomal hernias are repaired using various standard surgical techniques, but there is no one repair technique that is suited to all clinical situations, and all techniques are associated with hernia recurrence.
The general approaches for managing parastomal hernia include primary repair, mesh repair, and relocation of the stoma.
●Primary repair of the parastomal hernia is technically simple, avoids manipulation of the abdominal contents, and has low morbidity, but excessive tension on the repair leads to high recurrence rates. (See 'Primary repair' below and 'Recurrence' below.)
●Prosthetic mesh repair, which is the most common type of repair, closes the hernia defect using mesh placed anterior to the rectus or external oblique fascia (onlay) or below the fascia and muscular layers (preperitoneal or sublay technique) (figure 3). The mesh onlay technique is performed using open techniques, while the sublay technique is performed from an intra-abdominal approach (open or laparoscopic/robotic). (See 'Onlay versus sublay mesh' below and 'Onlay mesh repair' below and 'Intra-abdominal repair with mesh' below.)
●Relocation of the stoma to another site on the abdominal wall was once a common approach but is generally avoided because the new stoma is associated with the same high risk of hernia formation as the initial stoma [70,76]. The recurrence rate is approximately 36 percent (range 0 to 76 percent), and complication rates are as high as 88 percent [70,71,76]. When this option is chosen, the abandoned stoma site should be repaired using a mesh technique (onlay or sublay) rather than with a primary repair to avoid recurrent hernia and, more importantly, to limit tension on the abdominal wall that could lead to hernia formation at the new stoma site. (See "Overview of surgical ostomy for fecal diversion".)
Primary repair versus mesh repair — The overall success rate for parastomal hernia repair with mesh is relatively high compared with repair not using mesh. In a systematic review analyzing various techniques for repair of parastomal hernia, the risk for recurrent parastomal hernia was significantly higher for primary suture repair compared with mesh repair (odds ratio [OR] 8.9, 95% CI 5.2-15) [31]. However, all reports were nonrandomized, included small numbers of patients, and had variable follow-up. Mesh repair is still associated with recurrence rates of up to 30 percent [31,56,57,70-75].
Complications such as contamination of the mesh, erosion, and fistula formation, while rare, can be difficult to manage [74]. Thus, in general, although mesh repair is desirable, there may be circumstances under which a primary repair or relocation of the stoma may be preferred, even though the risk of recurrence is higher.
Open versus laparoscopic repair — Reports of decreased patient morbidity and improved outcomes with laparoscopic tension-free mesh repair of ventral and incisional hernias have led surgeons to apply these techniques to the repair of parastomal hernia [31,49,77-83].
There are very few data to determine which patients with parastomal hernia are best treated via a laparoscopic approach or an open approach. Based upon the experience with midline incisional hernias, laparoscopic repair is also best reserved for when the surgeon does not anticipate extensive intestinal adhesions or extensive anterior peritoneal wall scarring from prior surgery [84]. A laparoscopic approach may also be preferred for patients with smaller (<8 to 12 cm) hernias.
Onlay versus sublay mesh — The onlay mesh technique has the advantage of being technically straightforward and avoids the intra-abdominal dissection required for a sublay approach, which increases the risk for future abdominal adhesions and intestinal obstruction. However, similar to the surgical experience with incisional hernia repairs, the sublay technique is associated with fewer recurrences because intra-abdominal pressure cannot dislocate the mesh from the repair [85]. The main problems with the sublay technique are identifying the best material for the mesh and establishing the best site for its placement. The onlay technique is associated with a higher risk of wound/mesh infection.
TECHNIQUES
Primary repair — Parastomal hernia repair was once performed in a manner similar to traditional primary suture repairs of inguinal and incisional hernias, reducing the size of the hernia defect by reapproximating the fascial edges of the trephine with permanent sutures. Primary repair involves a dissection of the fascia at the site of the stoma. This approach can be performed locally at the parastomal hernia site extra-abdominally, intra-abdominally via a laparotomy incision, or laparoscopically. This approach is generally avoided because the physics of parastomal hernia and the nature of the defect unavoidably create tension on the repair, which leads to a high rate of recurrence.
Onlay mesh repair — Onlay mesh repair is performed by making an incision in the abdominal wall, typically in the midline, well away from the stoma. In some situations, a lateral incision may be appropriate. A subcutaneous dissection along the rectus and oblique fascia is performed circumferentially around the stoma. The contents of the hernia are reduced into the abdomen, and the abdominal wall defect is closed using a tension-free mesh repair. While all of the series describing this technique are small, nonrandomized, and lack long-term follow-up, these reports describe low perioperative complication rates but recurrence rates ranging from 0 to 20 percent.
Undermining the skin around the stoma also risks ischemic injury to the skin, which can result in significant management problems with the stoma appliance. The use of closed suction drains overlying the mesh appears to reduce complications resulting from seroma collections [57]; however, this needs to be balanced against the possible risk of mesh infection, which is higher for this technique than for intraperitoneal placement of mesh.
Intra-abdominal repair with mesh — The common aspect of each of the various approaches to intraperitoneal mesh placement is reduction of the hernia contents into the abdominal cavity and closure of the fascial defect by securing a piece of mesh under the defect with wide overlap onto the normal abdominal wall. Intra-abdominal access is usually accomplished by reopening the prior midline incision, but the incision can be made at other positions on the abdominal wall depending upon the size and nature of the parastomal hernia defect. However, the incision needs to be far enough away from the stoma to ensure that the stoma appliance will not cover the incision.
The loop of bowel forming the ostomy can be brought around the mesh (eg, Sugarbaker technique), similar to extraperitoneal ostomy construction, or directly through a defect in the mesh (ie, the "keyhole" technique) (figure 4).
●Sugarbaker technique – Sugarbaker was the first to describe the intraperitoneal mesh repair of a parastomal hernia [59]. This technique involves securing the mesh over the entire fascial defect circumferentially, but laterally, to create a mesh flap valve around the stoma. This prevents herniation and contact with the stoma bud, theoretically reducing infection. The bowel loop exiting at the stoma site is secured to the lateral and anterior abdominal wall, and then a large piece of mesh is attached to the anterior and lateral abdominal wall over this loop of bowel, preventing other loops of bowel from contacting or protruding through the abdominal wall at the trephine for the stoma.
●Keyhole technique – In the keyhole technique, a 2 to 3 cm "keyhole" cut-out is made to surround the ostomy while covering the entire hernia defect (Von Sprundel, Morris, Hofstetter, Byers). However, there is a risk of obstructing the enterostomy if a small keyhole is made and a risk of recurrence if the keyhole is large. Morbidity using this technique has been overall low.
Laparoscopic approach — The technique of laparoscopic parastomal hernia repair has not been standardized. Various methods utilizing different mesh materials have been reported by small, single-surgeon, retrospective studies [55,67,86].
Among them, the laparoscopic modification of the Sugarbaker technique is most widely used because it does not require apertures to be created in the mesh (figure 5), which simplifies its laparoscopic placement [67]. In a retrospective study of 62 patients who underwent parastomal hernia repairs, the laparoscopic Sugarbaker technique was associated with a lower complication rate (40 versus 76 percent) and a lower recurrence rate at 20 months (16 versus 60 percent) compared with other laparoscopic techniques [87]. However, longer-term follow-up results have not been reported for any of the techniques. (See 'Intra-abdominal repair with mesh' above and 'Recurrence' below.)
RECURRENCE — The various types of parastomal hernia repair are associated with a wide range of recurrence rates due to variations in the definition of a parastomal hernia recurrence, either radiographic, clinical, or symptomatic; type of stoma; size of hernia defect; indications for repair; and length of time of follow-up. Recurrence rates for primary suture repair are high, ranging from 30 to 76 percent [12,20,70,76,88]. In a systematic review, primary suture repair significantly increased the risk for recurrent hernia compared with mesh repair [31]. There were no significant differences between open and laparoscopic hernia repair for recurrence; the laparoscopic Sugarbaker technique had significantly fewer recurrences compared with a keyhole technique (odds ratio 2.3, 95% CI 1.2-4.6). The following recurrence rates were noted [31]:
●Primary suture repair – 69.4 percent
●Onlay mesh – 17.2 percent
●Sublay mesh – 6.9 percent
●Open, intraperitoneal mesh
•Sugarbaker – 15 percent
•Keyhole – 7.2 percent
●Laparoscopic mesh
•Sugarbaker - 11.6 percent
•Keyhole – 34.6 percent
•Sandwich – 2.1 percent
Recurrent parastomal hernia repair — Recurrent parastomal hernias present many challenges for repair. Recurrent repair is best done if there was no mesh used previously. If mesh was used as an onlay or sublay and the hernia recurred, one option is to perform a Sugarbaker repair. If all else fails, relocating the stoma to the other side of the abdomen and using prophylactic mesh during creation of the new stoma is the next best option.
PERIOPERATIVE MORBIDITY AND MORTALITY — Perioperative mortality following elective repair of parastomal hernia using commonly performed mesh repairs is low (<3 percent) but increases in emergency settings [89]. In a systematic review, laparoscopic repair had no advantage over open repair with respect to morbidity or mortality [31]. Complications following parastomal hernia repair are similar to those of any hernia repair and include recurrence (discussed above), inadvertent enterotomy, postoperative bowel obstruction, surgical site infection, mesh infection, and mesh erosion. Mesh erosion is a consequence of placing mesh adjacent to the bowel. Shrinkage of the mesh may lead to late erosion into the bowel [31,74].
Overall, wound/mesh infection rates following parastomal hernia range from 6 to 20 percent [31,90]. Infection rates for laparoscopic hernia repairs may be lower. Mesh infection results from contamination of the mesh at the time of placement or late seeding from hematogenous sources, which is less common but occurs at higher rates following repair of complicated parastomal hernia (eg, strangulation). (See "Wound infection following repair of abdominal wall 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
●A parastomal hernia is a type of incisional hernia that allows protrusion of abdominal contents through the abdominal wall defect created during ostomy formation or immediately adjacent to the stoma. The development of a parastomal hernia is an almost inevitable complication following the construction of an intestinal stoma. (See 'Introduction' above.)
●Risk factors for parastomal hernia are similar to those for other abdominal hernias and include advancing age, wound infection, chronic or recurrent increases in intra-abdominal pressure, chronic obstructive pulmonary disease, obesity, weight gain after ostomy construction, malnutrition, glucocorticoids, immunosuppression, malignancy, and inflammatory bowel disease. (See 'Epidemiology and risk factors' above.)
●Most patients with a parastomal hernia are asymptomatic. Patients typically present with a bulge at the site of or adjacent to the intestinal stoma, with or without associated pain (picture 1). Symptoms range from mild abdominal discomfort to symptoms of strangulated bowel obstruction, which can be life-threatening. The diagnosis of parastomal hernia is based on characteristic findings and physical examination. (See 'Clinical features' above and 'Diagnosis' above.)
●Patients with symptoms and signs of complicated bowel obstruction (complete, strangulated) should undergo urgent parastomal hernia repair. (See 'Acute complications' above and "Management of small bowel obstruction in adults".)
●For patients with mild or no symptoms referable to the parastomal hernia, we suggest conservative management rather than hernia repair (Grade 2C). Standard measures to care for the ostomy may be sufficient to relieve the patient's symptoms and concerns. If symptoms persist or the hernia progressively increases in size, the patient may elect hernia repair. (See 'Management' above and 'Indications for hernia repair' above.)
●For most patients, we suggest using prosthetic mesh for repair of the parastomal hernia rather than primary, suture repair (Grade 2B). The mesh can be placed extraperitoneally or intraperitoneally. (See 'Surgical approach' above.)
●For patients with appropriate indications for repair who have small defects (<5 inches) and no expectation of significant intra-abdominal adhesions, we suggest a laparoscopic approach rather than open repair (Grade 2C). (See 'Surgical approach' above.)
