Abdominal perineal resection (APR): Open techniques

INTRODUCTION — 

An abdominal perineal resection (APR) includes the resection of the sigmoid colon, rectum, and anus (figure 1) and the construction of a permanent end colostomy.

The open techniques of APR are described here. Minimally invasive techniques of APR are discussed in another topic. (See "Minimally invasive techniques: Left/sigmoid colectomy and proctectomy".)

INDICATIONS — 

Benign and malignant conditions that can be treated by APR include but are not limited to:

●Crohn proctitis with anal disease

●Ulcerative colitis, not a candidate or amenable to an ileal pouch anal anastomosis

●Fecal incontinence, not amenable to sphincter-sparing procedures

●Low-lying rectal cancer involving anal sphincter complex and/or positive distal margin

●Anal cancer, failed neoadjuvant therapy

●Anal cancer, recurrent

●Anal melanoma

PREOPERATIVE PREPARATION

Enterostomal assessment — Preoperative counseling and education with a skilled enterostomal nurse therapist and site selection for optimal placement of the ostomy are the key components of preoperative preparation. (See "Overview of surgical ostomy for fecal diversion", section on 'Preparation and counseling'.)

Mechanical bowel preparation — The use of mechanical bowel preparation (MBP) prior to colon and rectal surgery is controversial. There is no study that specifically addressed the necessity of an MBP for APR; given the dwindling number of APRs performed, such study is unlikely to be performed.

Extrapolating from studies on other major colorectal resections (eg, low anterior resection), an MBP is beneficial and should be performed routinely prior to APR. A review of the evidence for MBP is discussed separately. (See "Overview of colon resection", section on 'Bowel preparation'.)

Antibiotic prophylaxis — Prophylactic intravenous antibiotics are routinely administered within one hour of the surgical incision. The preferred agents can be found in this table under colorectal surgery (table 1). (See "Antimicrobial prophylaxis for prevention of surgical site infection following gastrointestinal surgery in adults", section on 'Colorectal procedures'.)

Given the existing data, oral antibiotics are best administered in conjunction with MBP on the day before elective colorectal surgery. This is discussed elsewhere. (See "Overview of colon resection", section on 'Bowel preparation'.)

Venous thromboembolism prophylaxis — Patients undergoing an APR are at a high risk for developing a deep venous thrombosis (DVT) [1,2]. All patients scheduled for an APR should receive primary prophylaxis. Prevention of DVT is discussed in detail separately. (See "Prevention of venous thromboembolic disease in adult nonorthopedic surgical patients".)

OPEN SURGICAL TECHNIQUE

Patient positioning — Attention to patient positioning is integral to preventing peripheral nerve injuries, pressure sores, deep vein thrombosis, and compartment syndrome (figure 2) [3]. To lower the risk of surface pressure and subsequent peripheral nerve injury, the authors place an inflated bean bag with a soft gel layer under the patient [4], which can be moulded around the patient when the air is evacuated. Operating room safety and a review of strategies to prevent nerve injury during pelvic surgery are reviewed separately. (See "Patient safety in the operating room" and "Nerve injury associated with pelvic surgery".)

To begin the operation, the patient is placed in the modified dorsal lithotomy position, and:

●Intermittent pneumatic compression pumps are applied to both legs.

●The legs are raised simultaneously and secured in boots.

●The legs should be at the same height with the hips and knees flexed at 45 to 60°.

●Adequate padding should be placed around the posterolateral aspect of the lower legs to prevent a common peroneal nerve injury.

●The buttocks should be extended slightly over the end of the operating table so that the sacrum is supported on the bean bag surface, even with the lower break of the procedure bed [5].

●The patient's arms should either be padded and secured by the side of the patient or secured on padded arm boards and extended no more than 90º [6].

●For the patient with severe obesity, special operating tables with side extensions are used for added support [7]. The shoulders should be padded to prevent pressure sores from the bean bag.

At the completion of the abdominal portion of the operation, the patient can either stay in the modified dorsal lithotomy position or be repositioned to the prone position for the perineal portion of the procedure. (See 'Repositioning for perineal resection' below.)

Exploration for resectability — Prior to initiating the resection, the abdomen is thoroughly examined for resectability of the sigmoid colon and rectum.

For patients with cancer, this evaluation includes an assessment of local, regional, and distant disease.

●The abdomen is explored for evidence of anomalies and/or metastatic disease, including peritoneal implants, hepatic metastases, and distant nodal metastases.

●The primary tumor is palpated to confirm its location. Local and regional resectability is determined by assessing tumor invasion into the pelvic walls or organs (eg, prostate, bladder, and uterus). The entire colon is palpated to identify synchronous colonic lesions.

Mobilization of colon — There are two approaches to mobilizing and resecting the sigmoid colon, medial to lateral (early ligation of vascular pedicle) or lateral to medial (early mobilization of the colon). The authors perform all dissections, both open and laparoscopic, in a medial to lateral fashion. (See "Left colectomy: Open technique", section on 'Mobilizing the left colon'.)

The advantages of the early division of the vascular pedicle include reduced bleeding during dissection, maximal time for sharp demarcation between ischemic and well-perfused bowel, and more efficient identification of the correct plane in the fine areolar tissue that connects the mesocolon to the mesentery. This approach helps to reduce the risk of injury to retroperitoneal structures such as the ureter.

Medial to lateral approach — The medial to lateral approach is ideal for resection of inflamed bowel and adjacent mesentery and for performing the "no-touch" approach to colon cancer resection (figure 3 and figure 4 and figure 5).

The general principles for performing a sigmoid colectomy, beginning with ligation of the mesenteric lymphovascular pedicle, include:

●Apply gentle traction to the sigmoid colon while the mesentery is incised using electrocautery behind the superior rectal artery (SRA), which overlies the sacral promontory (figure 6).

●Develop the avascular areolar tissue plane, located behind the SRA and anterior to the sacral promontory, laterally and diagonally over the pelvic brim.

●Perform the majority of the colon dissection with a gentle sweeping technique in the avascular plane. The colon is resected in a posterior to anterior motion to avoid injury to the underlying autonomic nerves and presacral venous plexus.

●Dissect in the avascular areolar tissue plane; a window is created and the ureters, gonadal, and iliac vessels are identified and preserved (figure 6). The left and right ureters are retroperitoneal and cross the iliac vasculature near the origins of the internal iliac arteries; the left ureter enters the pelvis at the apex of the sigmoid mesocolon. Dissection of the pelvic portion of the ureters should be performed medially to laterally, as the blood supply enters laterally.

●Incise the mesentery cephalad over the anterior surface of the aorta; the first major branch is the inferior mesenteric artery (IMA) (figure 3).

●Dissect the SRA to its origin from the IMA and ligate the SRA with a permanent tie suture (low tie method). This allows for removal of an appropriate amount of the associated lymphatics for a rectal cancer resection (figure 5). An alternative to the low tie method is the high tie method, where the IMA is ligated at its origin. The authors prefer the low tie method because it preserves the blood supply from the IMA to the left colon (left colic artery), without compromising survival for rectal cancer patients compared with the high tie method [8]. (See "Radical resection of rectal cancer", section on 'Vascular ligation'.)

●Release the left colon from its lateral attachments by retracting the sigmoid and left colon medially and incising the line of Toldt (figure 7). The dissection is continued medially to the previously developed space.

●Divide the colon with a linear stapling device near the junction of the descending and sigmoid colon to facilitate distal resection and prevent bowel spillage.

Lateral to medial approach — The lateral to medial approach is the traditional technique for mobilizing the colon in an open procedure. This technique includes the same principles for identifying and preserving the ureters and gonadal and iliac vessels and ligating the SRA as described in the above section.

Although this approach is more familiar to many surgeons, the disadvantages include potentially more blood loss from the early division of the lateral attachments prior to division of the vascular pedicles and more manipulation of the colon.

The general principles for performing a left colectomy, beginning with mobilization of the left colon, include [9]:

●Divide the lateral peritoneal attachments along the line of Toldt and mobilize the colon medially.

●Mobilize the IMA using blunt dissection in the avascular fusion plane.

●Identify the SRA as the artery passes into the pelvis at the base of the sigmoid mesentery.

●Mobilize the sigmoid colon and upper rectum in the avascular plane with a gentle sweeping posterior-to-anterior motion; the SRA is mobilized with the mesocolon.

Mobilization of rectum — Mobilization of the rectum is performed in the avascular presacral space between the fascia propria (the thin layer of fascia that encases the rectum and its lymphatics) and the presacral fascia (figure 8). Attention to detail is critical to avoid avulsion of the sacral plexus veins and middle sacral artery (figure 9) [9].

The general principles for mobilizing the upper rectum include:

●Gently retract the upper rectum anteriorly to facilitate identification of the avascular presacral space, using either the operator's nondominant hand or a St. Mark's deep pelvic retractor (picture 1).

●Identify and preserve the iliohypogastric nerves along either side of the rectum at the level of the sacral promontory (figure 10).

●Access the retrorectal space posteriorly in the midline, using electrocautery to divide the rectorectal fascia (Waldeyer's fascia) (figure 11) [10,11]. Precise dissection on the fascia propria reduces the risk of damage to the iliohypogastric nerves. Tethering from the lateral peritoneal reflexion is incised and divided. The lateral ligaments that contain the middle hemorrhoidal vascular pedicles are divided with electrocautery (figure 12 and figure 13). Circumferential dissection is completed by incising the peritoneum at the base of the cul-de-sac. Proceed with the dissection to the level of the pelvic diaphragm.

●Avoid injury to the posteriorly located parasympathetic fibers by using electrocautery judiciously when dissecting the posterior plane.

●Do not mobilize the mesorectum from the levator muscle at this time (figure 14). However, the bowel is divided at a level to permit at least a 5 cm margin proximal to the malignancy.

●Technical considerations when operating in the male pelvis (figure 15):

•Incise the peritoneum approximately 5 mm anterior to the fold of the cul-de-sac, exposing the seminal vesicles that are cleared by sharp dissection with electrocautery.

•Continue the plane of dissection anteriorly to encompass Denonvilliers' fascia [12], until reaching the junction with the prostate capsule. For rectal cancers located anteriorly, Denonvilliers' fascia is separated from the prostate capsule to provide a clear margin. For rectal cancers located posteriorly, the dissection is performed in the plane closer to the anterior surface of the rectum, leaving Denonvilliers' fascia intact to preserve the nerves.

•Terminate the mobilization anteriorly below the level of the seminal vesicles and posteriorly at the upper border of the coccyx.

●Technical considerations when operating in the female pelvis (figure 16):

•Retract the uterus superiorly using a St. Mark's retractor (picture 1) or by securing the uterus to the abdominal wall with a suture.

-Incise the peritoneum at the peritoneal reflection with electrocautery and dissect along the rectovaginal septum in the areolar tissue plane.

•Remove the vaginal segment en bloc if the tumor is tethered to the posterior wall of the vagina; the vaginal segment should be removed en bloc with the rectal specimen. The posterior vagina is reconstructed with absorbable sutures during the perineal portion of the procedure (figure 17).

-Avoid bearing in or coning the specimen during the circumferential dissection as this will compromise the circumferential resection margin.

•Terminate the mobilization anteriorly below the cervix uteri and posteriorly at the upper border of the coccyx (figure 14).

Colostomy construction — The colostomy is constructed prior to performing the perineal resection. The surgical principles of construction of an end colostomy, including technical insights and use of prophylactic mesh, are reviewed in detail separately. (See "Overview of surgical ostomy for fecal diversion".)

Omental flap — In patients who require adjuvant radiotherapy after surgery, an omental flap can be created by detaching the greater omentum from the transverse colon while keeping its vascular pedicle connected to the stomach. Once secured in the pelvic hollow with sutures, it serves to shield the small intestines and genitourinary organs from radiation damage [13].

Omental flaps were theorized to reduce perineal wound morbidity and aid in primary healing of the perineum. However, a systematic review and meta-analysis of 14 studies revealed no beneficial effect of omentoplasty on presacral abscess formation and perineal wound healing after APR, while it increased the likelihood of developing a perineal hernia [14]. (See "Prevention and management of perineal complications following an abdominal perineal resection", section on 'Prevention'.)

Repositioning for perineal resection — At the completion of the abdominal portion of the operation, the authors of this topic prefer to reposition the patient from the modified dorsal lithotomy to the prone position for the perineal portion of the procedure. The prone jackknife position is especially important for open extralevator abdominoperineal excision (ELAPE) for easier teaching and better visualization; laparoscopic or robotic ELAPE might not require a change in patient position due to a clearer and amplified field of vision [15]. (See 'Extralevator versus conventional approach' below.)

To change position, the boots are removed and the legs are slowly lowered to the operating table simultaneously. This will avoid injury to the hips from inadvertent rotation. The patient is now supine in preparation to be transferred to the prone (Kraske) jackknife position (figure 18).

Perineal resection — The general principles for performing the perineal resection include:

●Tape the buttocks apart and close the anus with a silk pursestring suture.

●Make an incision around the anus, extending to the lower edge of the sacrum.

●Dissect through the subcutaneous adipose tissue just outside the plane of the external sphincter (figure 14 and figure 19), using electrocautery and a self-retaining retractor (eg, Lone Star retractor system) to optimize exposure and access.

●Identify the levator muscle and dissect to the point of insertion of the muscle on the pelvic sidewall (figure 20).

Extralevator versus conventional approach — An APR can be performed following one of three lateral dissection planes [16]:

●Extrasphincteric plane – This is the conventional APR technique, which removes less tissue at the level of the tumor ("coning in"). Such a "waist" in the specimen can potentially lead to a positive circumferential radial margin [17].

●Extralevator plane – This is the ELAPE technique, also referred to as the cylindrical APR [18]. In this technique, the lateral limits of resection are extended to the origin of the levator muscles at the pelvic sidewall. ELAPE removes more tissue around the tumor and decreases the risk of tumor perforation at the point of separation of the rectum from the levator muscles. Thus, ELAPE is the preferred approach for low rectal tumors with involvement of the levators as shown by preoperative magnetic resonance imaging [19]. For those cases in which levators are not involved, ELAPE cannot be recommended over conventional APR because of a potential for higher perineal wound morbidities [20-22].

●Intersphincteric plane – This plane is reserved for resection of inflammatory bowel disease-related dysplasia or malignancy, or a very low rectal cancer that does not involve the anal sphincter complex. For such patients, the goal of an APR is to remove the entire rectal wall to achieve an adequate distal resection margin [23]. Leaving the external sphincter, which is not a part of the rectal wall, would ensure an easy, tension-free closure.

Perineal wound closure — The general principles for closure of the perineal wound after resection include:

●The perineal wound is closed in layers with a series of 2-0 absorbable sutures used to approximate the subcutaneous adipose tissue.

●An absorbable subcuticular suture is used to close the skin. In the majority of cases, we close the skin primarily.

●For defects too large for a primary closure, the perineal defect may require reconstruction with a biological mesh [24,25] or a myocutaneous flap, such as a pedicled gluteus maximus, gracilis, or rectus abdominal flap [26-28].

●Placement of peritoneal drains is per surgeon preference. (See "Prevention and management of perineal complications following an abdominal perineal resection", section on 'Prevention'.)

INTRAOPERATIVE CHALLENGES — 

Resection of the rectum is associated with several technical challenges, including preservation of the ureters and urethra, sacral venous plexus, and pelvic autonomic nerves.

Ureter and urethra — The ureter is at risk for transection or injury during the lateral mobilization of the colon and ligation of the superior rectal artery during the abdominal portion of the operation, while the urethra is at risk when performing the anterior portion of the perineal resection [29].

The following key points and maneuvers help identify and preserve the ureters [30]:

●The ureter never branches.

●The ureter shows evidence of peristalsis or vermiculation when manipulated.

●If the ureter cannot be identified distally due to inflammation or tumor, identify a more proximal portion and dissect distally.

●Avoid excessive dissection of the ureter to preserve blood supply and avert ischemic necrosis.

●Place ureteral stents prior to resection, particularly in settings of large cancers or previous pelvic surgery or inflammation [31].

●Identify all structures prior to division and ligation. Vascular ligation (eg, superior rectal artery) should not be performed prior to identification of the ureters.

●Palpate the indwelling urinary catheter to define the plane between the prostate and the rectum. The urethra is at risk of injury with anterior rectal tumors that require the resection of the prostate gland. If a urethral injury has occurred, then the catheter is typically visible.

The management of transection or other injury to the ureters is reviewed separately. (See "Surgical management of an iatrogenic ureteral injury" and "Management of intra-abdominal, pelvic, and genitourinary complications of colorectal surgery", section on 'Pelvic and genitourinary injuries'.)

Hemorrhage — Life-threatening hemorrhage can be encountered during the pelvic dissection and typically arises from injury to the presacral plexus or internal iliac vessels (figure 21). In the setting of bleeding from the presacral plexus, the first step is to apply pressure to the area and advise the anesthesiologist so blood products can be administered. Titanium thumbtacks can be used to directly compress the bleeding vein [32]. If local control measures fail, the pelvis is packed with laparotomy sponges, the procedure is terminated, and resuscitation is continued in the intensive care unit [33-35]. The pH, intravascular volume, and clotting status must be optimized prior to returning to the operating room, typically in 24 to 48 hours, to remove the packs and complete the planned procedure. (See "Evaluation and management of disseminated intravascular coagulation (DIC) in adults", section on 'Treatment'.)

If bleeding is from the internal iliac vessels, the first step is to obtain control by direct pressure proximally and distally and determine the source of the bleeding [36]. It is prudent to consult a vascular surgeon, if available. If a repair is unfeasible, or if the patient is becoming unstable, both the internal iliac artery and vein can be ligated if necessary.

The management of bleeding complications following colon and rectal operations is discussed separately. (See "Management of intra-abdominal, pelvic, and genitourinary complications of colorectal surgery", section on 'Major vessel injury' and "Management of intra-abdominal, pelvic, and genitourinary complications of colorectal surgery", section on 'Presacral bleeding'.)

Pelvic autonomic nerves — The pelvic autonomic nerves consist of sympathetic and parasympathetic components that regulate urinary and sexual function (figure 22 and figure 23).

Injury to the nerves can occur during the following steps of the operation:

●The sympathetic nerves are at risk of injury at their origin from the aortic plexus during ligation of the internal mesenteric artery (IMA) and at the sacral promontory during the division of the hypogastric nerves from the hypogastric plexus.

●The parasympathetic nerves are at risk of injury during the lateral dissection, especially during the division of the lateral ligaments and anterolaterally during the dissection behind the prostate and seminal vesicles.

●Interlacing sympathetic and parasympathetic nerve fibers from the pelvic plexus form the inferior hypogastric nerve plexus that innervates the rectum, bladder, ureter, prostate, seminal vesicles, and corpora cavernosa and are at risk when dissecting the rectum from these structures.

Damage to these autonomic nerves can lead to bladder and sexual dysfunction and is reviewed separately. (See "Management of intra-abdominal, pelvic, and genitourinary complications of colorectal surgery", section on 'Genitourinary complications'.)

POSTOPERATIVE MANAGEMENT — 

Patients are managed by the fast-track multimodal protocol. (See "Overview of enhanced recovery after major noncardiac surgery (ERAS)".)

Management of the colostomy is described separately. (See "Ileostomy or colostomy care and complications".)

PERINEAL WOUND COMPLICATIONS — 

Perineal wound complications are common. The incidence, risks, and management are discussed separately. (See "Prevention and management of perineal complications following an abdominal perineal resection".)

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

●Abdominal perineal resection – Abdominal perineal resection (APR) includes the resection of the sigmoid colon, rectum, and anus and the construction of a permanent end colostomy. (See 'Introduction' above.)

●Indications – The indications for an APR include benign conditions (eg, Crohn's proctitis) and malignancy (eg, low rectal cancers, recurrent anal cancers). (See 'Indications' above.)

●Preoperative preparation – Preoperative assessment includes an evaluation by an enterostomal nurse, mechanical bowel preparation, oral and intravenous prophylactic antibiotics, and venous thromboembolism prophylaxis. (See 'Preoperative preparation' above.)

●Surgical techniques – Key steps of the operation include:

•Colonic mobilization – The authors mobilize the colon using the medial to lateral approach by ligating the lymphovascular pedicle prior to mobilizing the colon. (See 'Mobilization of colon' above.)

•Rectal mobilization – Mobilization of the rectum is performed in the avascular presacral space between the fascia propria (the thin layer of fascia that encases the rectum and its lymphatics) and the presacral fascia. Attention to detail is critical to avoid avulsion of the sacral plexus veins and middle sacral artery. (See 'Mobilization of rectum' above.)

•Perineal resection – The perineal resection can be performed in the modified dorsal lithotomy or the prone (Kraske) jackknife position. For cases in which levators are not involved, we suggest a conventional APR rather than an extralevator resection (ELAPE) (Grade 2C). ELAPE has been associated with higher perineal wound complication rates than conventional APR. For low rectal tumors with involvement of the levators, ELAPE is required to achieve a negative circumferential radial margin. (See 'Perineal resection' above.)

•Perineal wound closure – The perineal wound can be closed primarily with sutures or with biologic mesh or myocutaneous flap reconstruction. Peritoneal drainage is optional. (See 'Perineal wound closure' above.)