Prevention and management of perineal complications following an abdominal perineal resection

INTRODUCTION — An abdominal perineal resection (APR) is a surgical procedure that removes the rectum and anus (perineal component) and creates an end colostomy (abdominal component). An APR is primarily used to resect a very low rectal or anal cancer. It also is a salvage treatment for recurrent rectal or anal cancer and is a surgical treatment for severe inflammatory bowel disease. (See "Abdominal perineal resection (APR): Open techniques".)

Following resection of the pelvic contents (eg, rectum, mesentery) and perineum (eg, pelvic floor musculature, anus), a large cavity is created that is partially surrounded by the pelvic bone. Serous fluid and blood accumulate in this space, which can serve as a reservoir for bacterial colonization and can contribute to wound infection and/or formation of a chronic perineal sinus. Wound infection and chronic nonhealing wounds predispose to perineal hernia formation.

The most frequent perineal complications of an APR include bleeding or hematoma, perineal sepsis, persistent perineal sinus, and perineal hernia. They will be the focus of this topic, along with measures to prevent and to manage such complications of an APR.

Other anastomotic and intra-abdominal, pelvic, and genitourinary complications of colorectal surgery are discussed elsewhere. (See "Management of anastomotic complications of colorectal surgery" and "Management of intra-abdominal, pelvic, and genitourinary complications of colorectal surgery".)

ANATOMY OF THE PERINEUM AND PELVIS — The perineum lies below the pelvic floor and anterior to the sacrum and coccyx. The perineum is bounded anteriorly by the pubic symphysis and the arcuate ligament, posteriorly by the coccyx, anterolaterally by the ischiopubic rami and the ischial tuberosities, and posterolaterally by the sacrotuberous ligaments (figure 1 and figure 2 and figure 3 and figure 4 and figure 5 and figure 6) [1,2].

INCIDENCES AND RISK FACTORS — The risk of perineal wound complications following an APR ranges from 14 to 80 percent and includes surgical site infection, abscess, dehiscence, and delayed healing [3]. A widely cited retrospective review of 153 patients undergoing APR reported a major perineal wound complication (>2 cm dehiscence, perineal abscess, or any wound requiring reoperation or readmission) rate of 14 percent and a minor perineal wound complication (<2 cm dehiscence, stitch abscess, or sinus tracts) rate of 24 percent [4]. A variety of patient, disease, and technical factors can contribute to the development of perineal wound complications [3,5,6].

●Patient factors – The two most significant patient-related risk factors are diabetes (odds ratio 5.58) and obesity (a 10 percent increase in wound infection rate for each unit increase in body mass index) [4,7,8]. Other risk factors include American Society of Anesthesiologists (ASA) classification, weight loss, malnutrition, anemia, tobacco smoking, and excessive alcohol consumption [4,7,9,10]. Preoperative medical optimization and a prehabilitation program, time permitting, may mitigate some of these risk factors. (See "Overview of prehabilitation for surgical patients".)

●Disease factors – APR performed for cancer or inflammatory bowel disease is associated with a higher risk of wound complications than one for other indications [4].

•Cancer – Patients with a diagnosis of anal or rectal cancer often require preoperative chemotherapy or radiation therapy, both of which have been shown to increase perineal wound complications after APR [8,11,12].

Additionally, APR performed for very low rectal cancer or anal cancer sometime requires extralevator dissection if the tumor invades the levator muscle on one or both sides. The extralevator abdominoperineal excision technique can result in a larger perineal defect than standard APR, and has been associated with higher wound morbidity rates in some studies [13-15]. (See "Abdominal perineal resection (APR): Open techniques", section on 'Perineal resection'.)

•Inflammatory bowel disease – Patients with inflammatory bowel disease, especially Crohn disease, often have perineal sepsis or fistulization, which can predispose to nonhealing wounds after APR [16]. In such patients, it is best to treat perineal wound problems locally with antibiotics, drainage, seton, or fecal diversion. A subtotal colectomy is preferred to a proctocolectomy in the acute setting. (See "Surgical management of ulcerative colitis", section on 'Emergency or urgent surgery'.)

PREVENTION — Meticulous surgical technique, including the avoidance of fecal contamination and control of hemostasis, is critical to reducing the risk of perineal wound complications. A variety of other technical points may also be beneficial:

●Antibiotics – Prophylactic antibiotics should be administered to all patients no later than 60 minutes prior to skin incision [17]. (See "Abdominal perineal resection (APR): Open techniques", section on 'Antibiotic prophylaxis'.)

Supplementary local application of absorbable gentamicin-impregnated collagen fleece sponges inserted into the sacral cavity (carriers releasing antibiotics) has been associated with a reduction of perineal wound infections and higher healing rates following an APR in some studies [18-20]. A systematic review including four trials and four studies (three comparative) did not find sufficient evidence to support the routine use of local gentamicin application for perineal wound healing [21]. However, the included trials and studies were so heterogenous that a meta-analysis by data pooling was not possible.

●Patient positioning – The perineal portion of the APR can be performed with the patient in either a lithotomy or prone (jack-knife) position. There is some evidence to suggest performing perineal resection in the prone position may be associated with a lower wound infection and dehiscence rate [22]. The rationale is that the prone position permits better visualization, exposure, and assisting. (See "Abdominal perineal resection (APR): Open techniques", section on 'Repositioning for perineal resection'.)

●Intersphincteric dissection for benign disease – When performing an APR for benign disease (eg, inflammatory bowel disease), the dissection should be performed in the intersphincteric space rather than the wide resection performed for malignancy [23]. The resultant perineal wound can be easily closed without tension by approximating the external sphincter muscles, which are not a part of the rectum. (See "Abdominal perineal resection (APR): Open techniques", section on 'Perineal resection'.)

●Meticulous dissection and hemostasis – Persistent and uncontrolled intraoperative bleeding is the typical cause of early, life-threatening postoperative perineal hemorrhage [9]. Thus, meticulous hemostasis during the perineal portion of the dissection is essential for reducing the risk of postoperative hemorrhage. (See 'Hemorrhage and hematomas' below.)

●Pelvic exclusion – Following resection of the rectum and anus, an inflexible dead space rendered by the surrounding bony pelvis results, allowing accumulation of exudative fluid and hematoma that provide a nidus for infection, abscess, and fistula or sinus formation. It stands to reason that filling or excluding this space with vascularized tissue may reduce perineal complication rates.

•Omentum flap – The tissue that is most abundant and the easiest to mobilize is the greater omentum. Indeed, both early trial and systematic reviews suggested that omentoplasty can reduce perineal healing time, wound infection, and wound dehiscence rates [24,25]. More recent studies, however, failed to confirm the same benefit for omentoplasty [26-28]. With the split data, we suggest that omentoplasty be used judiciously to ensure good perfusion of the flap that can reach the deep pelvis in order to avoid introducing ischemic (and potential future necrotic) tissue into the wound.

•Colon/uterus – Other organs that can be used to exclude the pelvis include the right colon and the uterus [29]. There are very little data published on this technique.

●Closure of the perineal wound – The perineal wound can be closed primarily with sutures, mesh reinforcement, or a flap. The United Kingdom guidelines state that most standard APR perineal wounds can be closed primarily, whereas primary closure, mesh use, and myocutaneous flap reconstruction can all be used following extralevator abdominoperineal excision (ELAPE) [30]. A European registry study reported that for non-ELAPE procedures, 54 percent of wounds were closed primarily without mesh, 29 percent with mesh, and 5 percent by a flap; for the ELAPE group, the perineal wound was closed primarily in 15 percent, with mesh in 55 percent, and with a flap in 21 percent [31].

•Primary closure – Primary suture closure of the perineum in layers is standard for conventional APR. Closure of the peritoneum (CPP) is recommended whenever possible to reduce the incidence of perineal wound complications and perineal hernia rates [32,33]. However, CPP is not always technically possible, especially with the ELAPE, but should be considered whenever possible.

•Pelvic floor reconstruction by tissue transposition – Autologous tissue transfer, or to move a piece of well-vascularized tissue from a nonradiated area to fill a voluminous defect such as the perineal wound after APR. It may be required for ELAPE or multivisceral resection where the perineal defect is too wide for primary closure, and for anal cancer where the perianal skin is heavily radiated. Common donor sites for myocutaneous transfer include rectus abdominis, gracilis, and gluteus, while a popular source of perforator pedicled flaps originates from the gluteal region [34].

In a meta-analysis of 10 mostly nonrandomized studies, myocutaneous flap reconstruction has been associated with fewer perineal wound complications than primary suture reconstruction [35]. The size of the perineal defect or the resection technique (conventional APR versus ELAPE) was not specified by the studies. Most patients received pelvic radiation preoperatively.

There is no consensus for the optimal flap for immediate repair of the pelvic defect [36]. The decision on the type of flap formation will be influenced by patient factors (current smoker, lifestyle factors), tumor factors (neoadjuvant therapy, size of defect to be repaired), and operative expertise in the unit offering the surgery. (See "Overview of flaps for soft tissue reconstruction".)

•Biologic mesh reconstruction – In both a randomized trial [37,38] and meta-analysis of retrospective studies [39,40], mesh reconstruction appears to lower perineal hernia rate, but not perineal wound complication rate. Thus, mesh is usually placed when repairing a perineal hernia, rather than when primarily closing the perineal defect.

When used in the perineum, mesh is sutured to the sacrum posteriorly, the remnant levator muscles laterally, and the transverse perineal muscle anteriorly to reconstruct the pelvic floor [37]. The mesh material has evolved from synthetic to biologic over the years.

●Closed suction drain – We suggest placing a transabdominal drain after an APR and to leave it in until the drainage is <30 mL per day. Closed suction drainage is associated with improved perineal wound healing [3,41,42]. A randomized trial of 165 patients undergoing APR for rectal cancer found that patients treated with closed suction drainage had a significantly higher rate of perineal wound healing at one month compared with patients treated with passive drainage (75 versus 61 percent) [42]. There are no high-quality data from large, randomized trials on optimal placement of the drains (transabdominal or transperineal) or the duration of usage. Drains typically remain in place for two to five days [43,44].

●Incisional negative pressure wound therapy (iNPWT) – Negative pressure wound therapy has been applied to the closed perineal incision to decrease perineal wound complications [45,46]. A systematic review of five studies (three retrospective studies, one case series, and a video case report) demonstrated a significantly decreased incidence of surgical site infection with the use of iNPWT compared with controls (9 versus 41 percent) [47]. The evidence is limited given the lack of large prospective studies, and, as such, a firm recommendation for iNPWT cannot be made.

HEMORRHAGE AND HEMATOMAS — The incidence of early and delayed postoperative perineal hemorrhage ranges from 0 to 4 percent [5]. Perineal bleeding can develop from several sources, including the presacral venous plexus, the prostate in men or vagina in women, the pelvic floor musculature, or distal branches of the internal iliac vessels. Life-threatening postoperative hemorrhage is related to lack of intraoperative control of hemostasis. Hematomas occur as fluid accumulates in an undrained or inadequately drained space. (See "Abdominal perineal resection (APR): Open techniques", section on 'Hemorrhage'.)

Presentation — Packing of the perineal wound is a maneuver used to control severe intraoperative pelvic and presacral hemorrhage. Early postoperative hemorrhage occurs with the first dressing change if the packing only temporarily tamponaded the bleeding vessels or if a hemostatic thrombus is dislodged while the dressing is removed. Delayed bleeding is caused by erosion of the packing into previously sealed blood vessels and often becomes evident when the packing is removed. (See "Management of intra-abdominal, pelvic, and genitourinary complications of colorectal surgery", section on 'Presacral bleeding'.)

Management — Management of perineal bleeding depends upon the source and severity of blood loss. For severe bleeding, such as bleeding from presacral or pelvic vessels, repacking serves as a temporizing measure until the patient is stabilized and transferred to the operating room where the bleeding source can be identified and adequately controlled. The management of presacral bleeding and other pelvic sources of bleeding is discussed elsewhere. (See "Management of intra-abdominal, pelvic, and genitourinary complications of colorectal surgery", section on 'Presacral bleeding'.)

For bleeding sites directly involving the perineal tissues, bleeding can be controlled with direct suture ligature of bleeding points, spray electrocautery, or application of topical hemostatic agents. Most minor venous bleeding can be controlled with temporary perineal packing, which usually stops the bleeding within 48 to 72 hours. Operative intervention is rarely required to localize and control the site of minor bleeding.

Outcomes — There are no high-quality data from randomized trials to determine the optimal treatment for perineal bleeding or to assess the outcomes of postoperative hemorrhage or hematoma formation. There is anecdotal evidence to suggest that perineal hemorrhage and hematoma predisposes patients to the development of subsequent perineal wound complications [48,49].

PERINEAL SEPSIS — Management of a perineal wound complication depends on the clinical findings (eg, fever, pain, drainage) and radiographic findings, if performed (eg, pelvic abscess).

Presentation — In the postoperative phase, patients typically present with drainage from the perineal wound. Purulent drainage suggests a deep organ space infection, enteric drainage suggests a fistula, and serous and voluminous drainage suggests possible bladder or ureter origin. A physical examination must be performed to directly assess the characteristics of the drainage, abscess formation, dehiscence, and small bowel or other organ evisceration. A computed tomography (CT) scan of the pelvis and a white blood count is indicated when the patient has pain and fever.

Management — The following steps are performed when managing a perineal wound complication:

●For patients with draining wounds in the absence of overt pelvic sepsis (eg, fever, pain), the management includes local wound opening and drainage, debridement of ischemic tissues, removal of foreign bodies, and packing with wet-to-dry dressings or the application of a vacuum-assisted closure device. (See "Basic principles of wound management" and "Negative pressure wound therapy".)

●For patients with a pelvic abscess, management includes administration of broad-spectrum intravenous antibiotics and image-guided percutaneous drainage.

●For patients with a complete perineal wound dehiscence, evisceration of bowel or other abdominal contents, or necrosis of the flap used to reconstruct the perineum, emergency operative intervention is required for reduction and packing via the perineum or even abdominal approach.

Outcomes — The majority of perineal wound complications are effectively managed when the above steps are followed. However, some perineal wounds fail to heal despite these measures, which are discussed in the following section. (See 'Persistent perineal sinus' below.)

Based upon evidence from retrospective reviews, it is inconclusive if there is an association between perineal wound infections following an APR for cancer and compromised oncologic outcomes [50-52].

●A retrospective review of 228 patients with rectal cancer who had undergone an APR with curative intent reported that the incidence of local recurrence was significantly higher in patients with perineal infections compared with those without a perineal infection (33 versus 9 percent), but the difference was not significant for an intra-abdominal infection (13 versus 9 percent) [50].

●However, a retrospective review of 258 patients reported identical local recurrence rate in patients who did and did not have septic complications (both 9.3 percent) [51].

●Another observational study of 473 patients who underwent laparoscopic APR reported worse overall and disease-specific survival in those who suffered a wound infection [53].

Although worse oncologic outcomes have been associated with infectious complications after colorectal resection [54], most investigations focused on anastomotic leaks, and no conclusion has been made specifically about perineal wound complications.

For patients who develop a perineal wound dehiscence, there is an increased risk of mortality. In a retrospective review of 249 patients undergoing an APR for rectal cancer, patients who developed a wound dehiscence had a shorter survival time compared with patients without a dehiscence (66.6 versus 76.6 months, hazard ratio [HR] 1.7, 95% CI 1.1-2.8) [52].

PERSISTENT PERINEAL SINUS — A persistent perineal sinus is a perineal wound that remains unhealed for longer than six months after surgery [55]. The sinus is typically a long fibrous tract covered by infected granulation tissue with a narrow external opening [56]. It is a common occurrence, especially in patients with Crohn disease undergoing intersphincteric dissection, with an incidence as high as 85 percent [57].

Presentation — Patients can present with pain, discharge, and bleeding from the sinus. Careful examination of the perineal area is essential to confirming the diagnosis, with wound cultures to identify a possible secondary infection and biopsy of the tract to diagnose malignant transformation or a local recurrence.

The sinus tract should be evaluated with imaging to define the anatomy and rule out causes of nonhealing such as an enteroperineal fistula, undrained sepsis, retained rectal mucosa, or retained foreign body. Magnetic resonance imaging of the pelvis is routinely performed as the initial imaging study, with sinography, small bowel series, and CT enterography used as adjuncts, depending on the index of suspicion of an enteroperineal fistula.

Management — Among patients with a persistent perineal sinus, initial conservative management with the application of topical analgesics, antiseptics, and local wound care can decrease perineal pain and alleviate odor but rarely results in complete healing [55].

As a result, early intervention is recommended. Vacuum-assisted closure (VAC) has the potential to assist with healing complicated perineal wounds [58,59]. (See "Basic principles of wound management".)

Operative repair is reserved for those who fail to heal with VAC therapy. There are no randomized trials to determine the optimal management of a perineal sinus, but the following options are available:

●Curettage and primary closure [60]. Minimally invasive techniques such as endoscopic application of electrocautery [61] and sinoscopic treatment [62] have been reported.

●Sinus excision with partial coccygectomy and either primary closure or reconstruction with a flap or skin graft [63].

●Cleft closure, which is a modification of the Bascom cleft lift for pilonidal disease [64].

●Reconstruction with split-thickness skin grafting, omentoplasty, gracilis muscle transposition, rectus abdominis myocutaneous flap, or gluteus maximus VY-advancement flap [65-67].

At the author's institution, we routinely perform a wide local excision of the sinus and sinus tract, with or without partial coccygectomy, and use VAC devices to facilitate healing by secondary intention. We reserve reconstruction with flaps for extremely large defects in otherwise suitable surgical candidates.

Outcomes — The rate of complete healing with the above techniques for patients with a persistent perineal sinus varies by the indication for the APR. In one study, the cumulative probability of perineal wound unhealed at 6 and 12 months after APR was 85 and 48 percent, respectively, for 81 patients who underwent APR for Crohn disease, in contrast to 21 and 13 percent, respectively, for 25 non-Crohn patients [57]. After a medical follow-up of four years, eight patients with Crohn disease (10 percent) remained with an unhealed wound, whereas spontaneous perineal healing occurred for all non-Crohn patients.

PERINEAL HERNIA — A perineal hernia, defined as a protrusion of intra-abdominal contents through a defect in the pelvic floor, may contain small bowel, large bowel, bladder, uterus, and/or omentum [9]. Perineal hernia is rare, with only 8 cases reported in 3761 APRs recorded in a Mayo clinic database [68].

Presentation — The most common symptoms include pain, discomfort when standing or sitting, urinary symptoms (eg, dysuria, stress incontinence), intestinal obstruction, and/or breakdown of the perineal skin [68-71]. A perineal bulge, wound dehiscence, or evisceration can be identified on physical examination. (See "Overview of abdominal wall hernias in adults", section on 'Perineal hernia'.)

Management — The management of perineal hernia depends upon the clinical presentation.

●In the acute setting with evisceration of the abdominal contents, immediate operative reduction and packing and/or reclosure are performed [9].

●In the elective setting for symptomatic patients, surgical repair of the perineal hernia is indicated. (See 'Surgical techniques' below.)

●In patients with an asymptomatic perineal hernia, surgical repair is not indicated. There are no high-quality data to suggest that repair of asymptomatic perineal hernias results in a reduction in complications such as incarceration or strangulation. We recommend counseling patients regarding the common symptoms associated with perineal hernias and prompt them to seek medical attention should these symptoms arise.

Surgical techniques — The surgical principles for repair of a perineal hernia are the same as for other hernias and include mobilization of the hernia sac, reduction of the contents, excision of the sac, and repair of the defect.

Several options for repair are available, including primary repair via the perineal approach, abdominal approach, or a combined approach, insertion of prosthetic or biologic mesh material, omentoplasty, closure with myocutaneous flaps (eg, gracilis flap, rectus abdominis flap), and/or retroflexion of the uterus. The procedures are challenging, and there is no consensus on the optimal repair.

There is no randomized trial that compares various repair techniques. Retrospective studies tend to be small and heterogeneous. Systematic reviews reach different conclusions depending on the individual studies included:

●In a 2023 systematic review and meta-analysis of 29 studies including 325 patients, perineal and abdominal repair were associated with similar hernia recurrence (19 versus 18 percent) and complication rates; the use of synthetic mesh was associated with reduced hernia recurrence rate, especially with abdominal repair (16 versus 30 percent) [72].

●Another 2023 systematic review of 20 studies including 213 patients reported that the perineal approach was both the most commonly used (56 percent) and the one with the highest recurrence rate (35 percent) [73]. Synthetic mesh repair with either combined abdominoperineal (0 percent), abdominal (8 percent), or laparoscopic (11 percent) approach was associated with fewer recurrences.

●A 2017 systematic review and meta-analysis of 21 studies including 105 patients concluded that perineal and laparoscopic approaches are currently the most commonly used techniques [74]. Primary defect closure was supplanted by synthetic or composite mesh placement. Use of flap reconstruction spread rapidly and the recurrence rate was low.

For elective perineal hernia repair, we suggest the abdominal approach because of superior visualization of the hernia sac and contents and therefore a lower risk of injury to major blood vessels and the bowel [75]. The abdominal approach also facilitates placement of mesh or a myocutaneous flap. Attempting to primarily repair the hernia from the perineum alone offers a limited exposure, and the pelvic floor must be reconstructed with limited anchoring points for the mesh.

At the author's institution, we perform an abdominal repair with mesh placement, using a running, continuous suture to secure the mesh to avoid creating smaller potential defects (as can happen with the use of interrupted sutures) through which incarceration and/or strangulation can occur.

Outcomes — The recurrence rate following repair of a postoperative perineal hernia is high regardless of approach and technique [68,76]. Thus, prevention of a perineal hernia with meticulous operative technique and primary closure of the perineum, as well as avoidance of perineal wound complications, is paramount.

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: Colorectal cancer" and "Society guideline links: Colorectal surgery for cancer".)

SUMMARY AND RECOMMENDATIONS

●Perineal wound complications – Perineal wound complications are common following an abdominal perineal resection (APR). The most frequent complications include hemorrhage, perineal sepsis, persistent perineal sinus, and perineal hernia. (See 'Introduction' above.)

●Risk factors – Patients who have diabetes and obesity have a high risk of developing perineal wound complications. Patients who undergo APR for inflammatory bowel disease and cancer also have a high risk of developing perineal wound complications. (See 'Incidences and risk factors' above.)

●Prevention – The technical principles that reduce perineal wound complications include prophylactic antibiotics, avoidance of fecal contamination, meticulous hemostasis, secure closure of the perineal wound with sutures, mesh, or flap, and closed-suction drainage of the pelvis.

Primary suture closure of the perineum in layers is standard for conventional APR. A myocutaneous flap may be required for extralevator abdominoperineal excision (ELAPE) or multivisceral resection where the perineal defect is too wide for primary closure, and for anal cancer where the perianal skin is heavily radiated. Mesh is usually placed when repairing a perineal hernia, rather than when primarily closing the perineal defect.

Other measures such as prone positioning, pelvic exclusion with omentum, and incisional negative pressure vacuum therapy are controversial. (See 'Prevention' above.)

●Hemorrhage and hematomas – Meticulous hemostasis must be achieved when performing an APR, particularly with respect to the presacral vessels, to reduce the risk of early postoperative hemorrhage. For severe postoperative bleeding, such as bleeding from presacral or pelvic vessels, repacking serves as a temporizing measure. For bleeding sites directly involving the perineal tissues, bleeding can be controlled with direct suture ligature of bleeding points, spray electrocautery, or application of topical hemostatic agents. (See 'Hemorrhage and hematomas' above.)

●Perineal sepsis – Treatment of infectious complications of the pelvis/perineum depends on presentation (see 'Perineal sepsis' above):

•For patients with draining wounds in the absence of overt pelvic sepsis (eg, fever, pain), management includes local wound opening and drainage, debridement of ischemic tissues, removal of foreign bodies, and packing with wet-to-dry dressings or the application of a vacuum-assisted closure (VAC) device.

•For patients with a pelvic abscess, management includes administration of broad-spectrum intravenous antibiotics and image-guided percutaneous drainage.

•For patients with either complete dehiscence/evisceration or loss of flap, urgent reoperative intervention and packing is required.

●Persistent perineal sinuses – A persistent perineal sinus is a perineal wound that remains unhealed for longer than six months after surgery. For persistent perineal sinus, we suggest an initial trial of a VAC closure (Grade 2C). Operative repair is reserved for those who fail to heal with a VAC closure. (See 'Persistent perineal sinus' above.)

●Perineal hernia – A perineal hernia is a rare complication following an APR. Treatment depends on the acuteness and symptoms of the presentation (see 'Perineal hernia' above):

•In the acute setting with evisceration of the abdominal contents, management includes immediate operative reduction and packing or reclosure.

•For elective repair of a symptomatic perineal hernia, we suggest an abdominal repair with mesh placement (Grade 2C). The abdominal approach offers superior visualization of the hernia sac and contents and therefore a lower risk of injury to major blood vessels and the bowel. Alternative techniques include the perineal or combined abdominoperineal approach with or without using mesh or myocutaneous flap. (See 'Perineal hernia' above.)

•Asymptomatic perineal hernias do not need surgical repair.

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Lara J Williams, MD, MSc, FRCSC, who contributed to an earlier version of this topic review.