C H A P T E R 65 • Miles Abdominoperineal Resection with Total Mesorectal Excision |
749 |
Patient lithotomy position
FIGURE 65–1
Midline incision
Foley catheter
Purse-string suture closing anus
Line of incision for perianal dissection
Coccyx
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2. DISSECTION
Once the peritoneum has been entered, a systematic exploration is performed to search for metastases in the peritoneal cavity, including the liver and the preaortic and iliac lymph nodes.
A fixed retractor is placed to retract small bowel superiorly and laterally out of the operative field. Retraction of small bowel is aided by placing the patient in a Trendelenburg position.
Mobilization of the sigmoid colon is achieved by using electrocautery to incise the lateral visceral fascia covering the mesosigmoid along the white line of Toldt, which can be easily visualized by retracting the sigmoid colon medially (Figure 65-3). The left ureter is identified along its course over the left iliac vessels into the pelvis.
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Line of transection |
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through peritoneum |
Rectum |
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and mesocolon |
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Sigmoid colon
Inferior mesenteric vessles
C H A P T E R 65 • Miles Abdominoperineal Resection with Total Mesorectal Excision |
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The medial visceral fascia is incised with electrocautery, and the right ureter is visualized as it courses over the right iliac vessels (Figure 65-4). The line of proximal resection is also outlined but not carried out until the tumor is able to be fully mobilized.
Line of peritoneal incision for abdominoperineal resection
Iliac vessels
Ureter
Inferior mesenteric vein
Inferior mesenteric artery
FIGURE 65–4
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The presacral space is entered by dividing the loose areolar tissue at the level of the sacral promontory. The presacral space is developed sharply with electrocautery caudally toward the levator ani muscle under direct vision. A fiber-optic pelvic retractor is used for retraction of the bladder and the rectum to facilitate visualization in the pelvis. Mobilization of the rectum continues caudally to the levator ani muscle. After the sharp posterior pelvic dissection is completed, the distal extent of dissection can be manually evaluated (Figure 65-5). Care must be taken to avoid injuring the presacral plexus of veins during the posterior dissection.
C H A P T E R 65 • Miles Abdominoperineal Resection with Total Mesorectal Excision |
753 |
The mesorectum is mobilized laterally toward the right and left pelvic side wall, preserving the hypogastric nerves on the sacrum. The lateral attachments to the pelvic wall containing the mesorectum are divided either with clamps and sutures (Figure 65-6) or with a vessel-sealer device, such as LigaSure.
The rectum is mobilized ventrally by dividing the rectovaginal septum or the rectovesicle space. In males, the dissection plane is ventral to Denonvillier’s fascia, preserving the seminal vesicles.
Attention is directed toward the resection of proximal sigmoid colon. First, the inferior mesenteric artery is divided just distal to the origin of the left colic artery either with clamps and sutures or with a vessel-sealer device. Next, the proximal sigmoid colon is divided with a gastrointestinal anastomosis (GIA) stapler (Figure 65-7).
Division of lateral attachments
FIGURE 65–6
GIA stapler used for transection of proximal sigmoid colon
FIGURE 65–7
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A colostomy site is created in the left lower quadrant at either the premarked site or halfway between the umbilicus and the left anterior superior iliac spine. A 2 cm in diameter circle of skin is excised with a scalpel, and the subcutaneous tissue is divided with electrocautery. A cruciate incision is made in the anterior rectus abdominis fascia, and 2 cm of the rectus abdominis muscle is divided with electrocautery. The peritoneum is incised with electrocautery to complete the colostomy site, which should be approximately 2 fingerbreadths in diameter.
The perineal dissection may be performed sequentially or simultaneously by a second team. After skin incision, the laterally ischiorectal space is entered. The skin and subcutaneous tissue is retracted with a self-retaining retractor to facilitate deep dissection (Figures 65-8 and 65-9). Inferior hemorrhoidal vessels are secured with sutures and divided. The coccyx is identified posteriorly, and the anococcygeal ligament located posteriorly is divided. Laterally, the levator ani muscle is divided with electrocautery and the perineal fossa is entered.
The distal stump of the transected sigmoid colon and the proximal rectum is delivered caudally through the opening of the levator ani muscle (Figure 65-10). Ventral mobilization of the rectum is facilitated by the anterior retraction of the skin and subcutaneous tissue and the posterior retraction of the sigmoid colon and rectum. The superficial transverse perineal muscle is divided with electrocautery to completely mobilize the rectum. In males, the urethra courses ventrally to the superficial transverse perineal muscle and can be identified and protected by palpating the urinary catheter. The sigmoid colon and rectum are removed through the perineal wound.
Line of incision for perianal dissection
C H A P T E R 65 • Miles Abdominoperineal Resection with Total Mesorectal Excision |
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Levator ani muscle and vessels
Perineal fossa
Ligated hemorrhoidal vessels
FIGURE 65–9
Transected stump of sigmoid colon and proximal rectum drawn through opening in levator ani muscle and peritoneum
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3. CLOSING
The pelvis is irrigated with saline, and hemostasis is obtained. Two Silastic 10-mm drains are placed in the pelvis through stab incisions in the right and left gluteal regions, lateral to the perineal wound, and secured with sutures of 2-0 nylon. The levator ani muscle is reapproximated with a running suture of 2-0 Vicryl (Figure 65-11).
The subcutaneous tissue of the perineum is reapproximated with a running suture of 3-0 Vicryl. The skin is closed with interrupted vertical mattress sutures of 2-0 nylon (Figure 65-12). The perineal incision is covered with povidone-iodine ointment and nonadhesive gauze.
A pedicle of the greater omentum is mobilized from the transverse colon and placed into the pelvis to promote healing and prevent small bowel adhesions in the pelvis (Figure 65-13). The proximal end of the resected colon is brought through the colostomy site, and the serosa of the colon is secured to the peritoneum with several interrupted sutures of 3-0 silk.
The midline abdominal incision is closed by reapproximating the fascia in one layer with two running absorbable sutures of loop 0 polydioxanone (PDS), beginning at the cranial and caudal end of the incision. The skin is reapproximated with staples.
The colostomy is matured by first removing the staple line with electrocautery. The fullthickness colonic mucosa is sutured to the dermis of the colostomy site circumferentially with interrupted sutures of 3-0 Monocryl. The colostomy is covered with a stoma appliance.
The nasogastric tube is removed before the patient awakes from anesthesia.
C H A P T E R 65 • Miles Abdominoperineal Resection with Total Mesorectal Excision |
757 |
Drains in place
Closing levator ani muscle with running sutures
FIGURE 65–11
Omentum
FIGURE 65–12 |
FIGURE 65–13 |
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STEP 4: POSTOPERATIVE CARE
Clear liquids are started on postoperative day 1, and diet is advanced as tolerated.
Postoperative antibiotics are not necessary.
A urinary catheter is left in place for 3 to 5 days to decrease the risk of urinary retention after pelvic dissection.
STEP 5: PEARLS AND PITFALLS
Obstructing rectal cancer may require a two-stage operation: a diverting descending colostomy, preoperative chemoradiation treatment, and a Miles abdominoperineal resection.
Large anal or distal rectal lesions will require wider perineal resection and may require a rectus abdominis myocutaneous flap to close the perineal wound. Patients who received preoperative chemoradiation treatment should also be considered for perineal reconstruction with a myocutaneous flap. Alternatively, the perineal defect can be left open and covered with a wound V.A.C. to allow healing by secondary intention.
SELECTED REFERENCES
1. Havenga K, Grossmann I, DeRuiter M, Wiggers T: Definition of total mesorectal excision, including the perineal phase: Technical considerations. Dig Dis 2007;25:44-50.
2. Fry RD, Mahmoud N, Maron D, et al: Colon and rectum. In Townsend CM (ed): Sabiston Textbook of Surgery, 18th ed. Philadelphia, Elsevier Saunders, 2008, pp 1348-1432.
