I. Introduction
When a person hears about rectal surgery, they often react with fear. Since the rectum is often a source of both benign and malignant disease, it is frequently treated with medications or surgery. But when hearing of the need for surgery, patients often worry about the need for an ostomy or “bag.” The goal of this Knol is to give you a brief overview of the types of surgery performed on the rectum. While it may be somewhat technical, our goal is to be comprehensive and accurate so that you can discuss with your surgeon the major issues involved with any rectal operation. We will start with a discussion of surgery for rectal cancer and then discuss surgery for benign (non-cancer) conditions.
II. Surgery for Rectal Cancer
Each year in the United States, approximately 42,000 patients are diagnosed with rectal cancer1, and 8,500 patients will die of this disease. While the treatment of rectal cancer frequently involves chemotherapy and radiation, surgical resection (removal by surgery) is essential for cure. The five-year survival rates following potentially curative surgical resections vary based on the stage of the disease, and generally range from 80-90% for patients with stage I disease down to 30-40% for patients with stage III disease.
The surgical management of rectal cancers depends on a number of factors, including stage, tumor size, location within the rectum, depth of invasion into the wall of the rectum, and involvement of the sphincter complex (the muscles responsible for the voluntary control of defecation). Select patients with small, superficial tumors with no evidence of spread to the lymph nodes may be candidates for limited surgery via a local excision. However, the majority of patients will require more extensive procedures such as low anterior resection (LAR) or abdominoperineal resection (APR) for management of their rectal cancer. This last operation is the procedure that leads a patient to having a permanent ostomy or “bag.” It is only recommended as a last resort, however, many patients live productive and active lives with the ostomy.
a. Anatomy of the Rectum
The rectum comprises roughly the last 20 centimeters of the large bowel. While it is similar to the rest of the colon in that it contains the same layers of tissue, there are some distinct anatomic considerations that make rectal surgery different from colon surgery. The upper rectum begins within the abdominal cavity and can be identified at the point where three longitudinal strips of muscle (the tenia coli) converge. From there, the middle rectum descends within the bony pelvis and runs between the sacrum and the bladder/prostate in males and the sacrum and uterus/vagina in females before terminating at the anus. Several nerves, including those responsible for proper sexual function in both sexes, run in close proximity to the rectum, and care must be taken to preserve the nerves during any operation.
The blood supply to the rectum comes from several different sources. The superior rectal artery arises as the end branch of the inferior mesenteric artery. The middle rectal arteries are branches off of the internal iliac arteries, and the inferior rectal arteries come from the pudendal arteries. The venous drainage follows these three different arteries and therefore can either go to the liver, or bypass the liver through the internal iliac veins into the inferior vena cava. This is important, as it can allow metastases (cancer growth away from primary tumor) to travel not only to the liver, but also to other distant sites like the lungs and brain without traveling to the liver first.
In the lower rectum, there are a number of muscles referred to as the sphincter complex that are responsible for the voluntary control of bowel movements. These muscles are left intact whenever possible in order to prevent incontinence postoperatively. However, in certain situations, it becomes necessary to sacrifice the sphincter complex and leave patients with a permanent ostomy. This will be discussed in greater detail below.
b. Resection Margins
The term margin refers to the distance between the edge of the surgically resected specimen and the edge of the tumor. Gross margins are calculated based on the edge of the tumor as it can be seen with the naked eye, while pathologic margins are determined using the microscopic edge of the tumor. In surgery for rectal cancer, there are three margins of interest: the proximal margin, the distal margin, and the radial margin.
The proximal margin refers to the distance between the proximal cut edge (the edge of the specimen that is closer to the mouth) and the beginning of the tumor. It is currently recommended that this margin be at least 5 centimeters in length2. While the proximal margin is certainly important, the distal margin and radial margin are more critical for preventing local recurrence of rectal cancer.
The distal margin, which refers to the distance between the end of the tumor and the cut end of the specimen that is closer to the anus, has been a subject of great debate. The traditional belief was that a 5-centimeter margin was necessary for an adequate surgical resection. However, more recent studies have shown that there were no statistically significant differences in rates of local recurrence or survival between patients with <2cm, 2 to 2.9cm, and >3cm margins3. Therefore, the current recommendations are for a distal margin of at least 2cm whenever possible2, however, a shorter margin is sometimes accepted if this means that the patient will be spared a permanent colostomy. Radial margins refer to the circumferential amount of normal tissue between the edge of the tumor and the edge of the resected tissue. The importance of adequate radial margins in the prevention of local recurrence has only recently been appreciated, but appears to be beneficial both in terms of decreased local recurrence as well as improved overall survival. The importance of negative radial margins has led to the acceptance of the Total Mesorectal Excision (TME), which will be discussed in further detail later in this chapter.
c. Bowel Preparations
The goal of mechanical bowel preparation (cleansing of the bowel) is to reduce the amount of feces in the colon. This in turn makes the bowel easier to handle during the operation and reduces the chance of fecal spillage, which can lead to contamination of both the abdominal cavity and the wound. Most surgeons prefer preparation of the bowel prior to surgery with a mechanical bowel preparation, as well as a combination of oral and intravenous antibiotics. The addition of oral and intravenous antibiotics reduces the bacterial count of the colon and helps prevent infection should fecal contamination occur.
Most bowel preparations will require that you eat no solid foods the day before surgery. Instead, you will likely be instructed to have only clear liquids on the day prior to surgery and then nothing from midnight on. A number of products are currently used for mechanical bowel preparation, and the choice of bowel prep depends on your other medical illnesses as well as surgeon preference.
Polyethylene Glycol (PEG), which is used in products like GoLYTELY and NuLYTELY (http://www.nulytely.com/), is administered as a 4-liter solution that is drank the day prior to surgery. Patients are instructed to drink roughly 8 ounces every 15 minutes over 4 to 6 hours or until their bowel movements are clear of particulate matter. This regimen is not associated with severe electrolyte imbalances and therefore is ideal for patients with kidney disease. However, the large volume of salty-tasting liquid that must be drank can lead to nausea, bloating, and vomiting and should not be used in patients with disorders of gastric motility such as diabetes.
Sodium phosphate solutions, such as Fleets Phospho-soda(http://www.phosphosoda.com/), are an alternative to PEG preparations. It is usually given as two separate doses of 45mL of medication, each diluted in a glass of water. It does not require the ingestion of large volumes of fluid used for the PEG preps, but has been associated with some severe electrolyte disorders and should be avoided in patients with renal failure, cirrhosis, ascites (a collection of fluid in the abdomen), and a number of other medical conditions. Enemas can also be given on the morning of surgery to further wash out any particulate matter that may remain following either of these preparations.
The oral antibiotics administered as part of some bowel preparations are either minimally absorbed or not absorbed at all, and therefore help decrease bacterial counts in the colon. Most surgeons use a combination of neomycin and erythromycin, but some have started using a combination of ciprofloxacin and metronidazole to avoid the cramping associated with erythromycin. Intravenous antibiotics are given before incision, so that they reach maximal tissue levels at the time of operation. The use of intravenous antibiotics decreases a variety of postoperative infectious complications and is well supported in the literature.
d. Standard Resections
Two different standard resections are employed in the treatment of rectal cancer: the low anterior resection and the abdominoperineal resection. Both of these operations involve the removal of portions of the rectum through similar operative techniques. However, there are some important differences, which will be discussed in the following sections.
Low Anterior Resection
Low Anterior Resection (LAR) involves the removal of a portion of the rectum including the tumor, while maintaining continence by preserving the sphincter complex. LAR is the treatment of choice for upper and middle rectal lesions as well as some lower rectal lesions where there is enough distance between the end of the tumor and sphincter complex to ensure a 2cm distal margin. Therefore, during an LAR, the sphincter complex is preserved and the patient should have normal or near-normal bowel control as long as they do not require a temporary diverting ileostomy, which will be discussed later.
The LAR begins with an incision in the middle of the abdomen that usually starts beneath the belly button and extends downwards towards the pubic bones. The fatty and muscular tissue beneath the skin is also divided in the midline until the abdominal cavity is entered. After placing a variety of retractors (surgical instruments used to hold tissue or organs out the way) that help to obtain an isolated view of the colon and rectum, the rectum is dissected (separated) free of its surrounding attachments and care is made to divide large blood vessels with minimal blood loss. The rectum is divided proximally and the dissection is carried down in the pelvis making sure to excise the rectum as well as its surrounding fatty tissue, referred to as the mesorectum. Care is also taken to identify and preserve the ureters, which are the tubes that drain urine from the kidneys into the bladder, and the nerves, which are responsible for sexual function. The dissection is carried down below the level of the tumor and the rectum is stapled off distally. At this point the surgeon can choose a variety of techniques to reconstruct the bowel. Frequently, a stapling device is used to reconnect the two ends (see Figure 1), and other times the surgeons will sew the two ends together by hand. In the majority of cases, the operation ends at this point and the abdomen is closed. In certain situations, such as a very low anastomosis, previous radiation to the pelvis, or any concern about the anastomosis (reconnection of the two ends of the bowel), the surgeon may choose to create a temporary ileostomy (an ostomy created out of the small intestine) to divert the stream of feces and provide the anastomosis with the adequate environment for healing.
Figure 1 – Stapled Anastomosis
Complications of an LAR include infectious complications, such as wound infection or abdominal abscess. Bleeding is another frequent complication and can come from any of a number of named and unnamed vessels encountered during the dissection. Anastomotic leak, which is a leak from where the bowel is put back together, is one of the most feared complications and can occur for a variety of reasons. When unrecognized, anastomotic leaks can lead to profound illness and potentially even death. Treatment of anastomotic leaks involves a combination of drainage of any infectious or fecal collections as well as diversion of the fecal stream via either a colostomy (an ostomy created out of the large intestine) or ileostomy. Additional complications include injury to the ureters, bladder, prostate, and vagina, as well as sexual dysfunction, deep venous thrombosis, and pulmonary embolism.
Abdominoperineal Resection
The Abdominoperineal Resection (APR) is reserved for cancers of the lower rectum where an acceptable distal margin between the tumor and the sphincter complex cannot be obtained. Therefore, the sphincter complex and anal canal are excised with the specimen, leaving the patient with a permanent colostomy.
APR begins similarly to an LAR, with a lower midline incision and careful dissection of the rectum as described above. However, once the abdominal portion of the rectal dissection is down to the pelvic floor, a second incision in the perineum is created. This incision encircles the anus and the sphincter complex, and the dissection is carried upwards through a muscle called the levator ani until it joins the abdominal portion of the dissection. At that point, the rectum is delivered through the perineal incision and the dissection is completed. The perineal incision is then irrigated and closed in several layers to prevent postoperative wound infection or dehiscence (separation of the wound).
Once the perineal wound has been closed, the stapled proximal end of the rectum is brought up to the abdominal wall as an end-colostomy. The midline wound is then irrigated, closed, and a sterile dressing is placed before the ostomy is opened or matured to prevent contamination of the wound with fecal content. Once this has been done, the ostomy is created using a number of sutures to secure the bowel to the skin while everting the bowel edge. Upon maturation of the ostomy, a stoma appliance (the actual bag and the other devices used to connect it to the skin) is placed and the procedure is concluded.
Complications of an APR are similar to an LAR and again include infectious complications, bleeding, inadvertent injury to surrounding structures, sexual dysfunction, and deep venous thrombosis. The perineal wound is at high risk for failure and patients are often asked not to sit up for several days to allow for proper healing. Additionally, the presence of an ostomy leads to several other potential complications, including stomal prolapse (displacement), stomal retraction, skin irritation, and difficulty with the appliance. Patients have also reported psychosocial changes and alterations of self perception from the presence of their ostomy.
e. Total Mesorectal Excision
The term Total Mesorectal Excision (TME) is used to describe the removal of the rectum along with its surrounding fatty tissue, blood supply, and lymph nodes, which is known as the mesorectum (See Figure 2). The first TME was described by Heald and Ryall in 19864, and its goal is the removal of the entire rectal mesentery in order to achieve a negative radial margin. Since the introduction of TME, numerous studies have found that it is associated with improved rates of local recurrence and overall survival5-8. The TME removes any disease that may have spread in the perirectal fat either above or below the level of the lesion. As an added benefit, the TME has been found to reduce the rate of postoperative impotence and retrograde ejaculation9,10. While the TME dissection is associated with a slight increase in the rate of anastomotic leak, the benefits of TME clearly outweigh the small additional risk of anastomotic leak.
Figure 2 – Total Mesorectal Excision
f. Laparoscopic Rectal Surgery
While laparoscopic surgery has been shown to have equivalent outcomes compared to open surgery for cancer of the colon, there is currently no definitive evidence that laparoscopic surgery for rectal cancers is associated with similar long-term results compared to LAR or APR. That being said, laparoscopic-assisted LAR and APR have been performed and can achieve many of the goals of open surgery11. The benefits of laparoscopic surgery include improved cosmesis (preservation of appearance) from smaller incisions, decreased postoperative pain, shorter length of hospital stay, and earlier return to normal activity. However, laparoscopic surgery is also associated with longer operative times and some specific complications such as port-site recurrences (tumor growing back at the skin incision of the laparoscopic port) and hernias. Laparoscopic surgery has also been associated with higher rates of sexual dysfunction in men. While laparoscopic rectal resections are not the current standard of care, there are some experienced surgeons who are able to perform this procedure with acceptable outcomes. If this is something that you are interested in pursuing further, be sure to find an experienced practitioner, but also keep in mind that the goal of any cancer surgery is to successfully remove the cancer. Until studies are performed that show that laparoscopic or “hand” assisted surgery has the same cancer survival rates, the standard of care are still the “open” operations.
g. Local Excision of Rectal Cancer
Local excision of rectal cancer involves the removal of the tumor alone without a resection of the remainder of the rectum or the surrounding mesorectum. Only patients with tumors that meet a specific set of characteristics are candidates for local excision, and even then they may be at an increased risk of local recurrence compared with patients who undergo LAR or APR. Tumors that are amenable to local excision must be small, well or moderately “differentiated” on the biopsy, and most importantly must have specific pathologic characteristics. Several studies have shown very poor results following local excision for patients with lymph node metastases and for patients whose tumors invade beyond a certain level of the bowel wall12-15. All patients seeking local excision should be evaluated with either endorectal ultrasound or endorectal MRI to assess for the presence of lymph node metastases and the level of tumor invasion. Patients with tumors that invade beyond the submucosa of the rectum or that have any suspicious lymph node metastases should not be offered local excision. They should either have more extensive surgery or a combination of chemotherapy and radiation with the local excision. However, patients with tumors limited to the submucosa and no evidence of lymph node metastases, or patients with profound medical problems who are not candidates for standard resections may be appropriate for local excision of their rectal cancer.
Transanal Approach
The transanal approach to local excision involves the removal of the tumor with a surrounding piece of rectal tissue through the anus (See Figure 3). Depending on where in the rectum the tumor is located, the patient can be placed in a variety of positions on the operating table to make accessing the tumor easier for the surgeon. The anus is then dilated initially with the surgeon’s fingers and then with a variety of dilators that can be used both for dilation and for exposing the lesion. Once adequate exposure has been obtained, a full thickness excision of the tumor with a 1-centimeter margin down to the perirectal fat is performed.
Figure 3 – Local Excision via Transanal Approach
Most local excisions are performed as outpatient procedures and do not require an overnight hospital stay. While local excision is associated with fewer complications than LAR and APR, there is still a risk of bleeding, infection, and urinary retention following local excision. Additionally, for tumors that are higher in the rectum, there is also a chance of perforation into the abdominal cavity, which may require an operation to fix. Additionally, local excision does not allow for a thorough pathologic assessment of disease, as the regional lymph nodes are not excised with the specimen.
Transanal Endoscopic Microsurgery
Transanal Endoscopic Microsurgery (TEM) is a relatively new technique that uses an operating microscope and special instruments to perform local excisions. The microscope allows for the excision of lesions that are located in the more proximal rectum that were not previously amenable to local excision via the transanal approach. Additionally, some studies have shown equivalent outcomes with TEM16-19. TEM is currently not performed at all centers and should only be performed by surgeons with considerable experience.
h. Ostomies – The patient’s worst fear
The greatest fear amongst patients requiring surgery on the rectum is that they will awaken with an ostomy (See Figure 4). An ostomy is a connection between the bowel and the skin of the abdominal wall so that bowel contents exit the body into a bag attached to the skin rather than through the anus. While an ostomy is a truly life-changing experience, and will affect you in many profound ways, it is important to know both why ostomies are necessary and the benefits associated with them, should you in fact need one.
Figure 4 – An Ostomy
So who needs an ostomy? All patients who require an APR for the treatment of their rectal cancers will be left with a permanent colostomy. Many patients have reported profound psychosocial changes in their lives with a permanent ostomy, and many patients who worked prior to their APR did not feel comfortable returning to work following the procedure20. These ostomies can be a source of embarrassment with potential leakage of foul smelling contents, uncontrollable passage of flatus, and difficulty wearing certain clothing that may interfere with the appliance. Unfortunately for patients who require an APR, there are currently no other options than a permanent colostomy. Thankfully, with new products, proper construction at surgery and the teaching of ostomy patients by a group of nurse specialists, the vast majority of colostomy patients have no complications such as leakage. They are able to do any and all activities in a normal life and have no restrictions on their diet.
The majority of patients who undergo an LAR do not require any form of ostomy. However, in certain situations, such as a very low anastomosis, previous radiation to the pelvis, or any concern about the anastomosis, the surgeon may choose to create a loop ileostomy (See Figure 5). These ileostomies are used to divert the fecal stream and allow the anastomosis to heal without being disturbed by the presence of hard stool. These ileostomies are often reversible and are usually taken down within a few months of the initial operation. Reversal of an ostomy does require a separate operation as well as a couple of days in the hospital to recover. The overwhelming majority of surgeons will use a loop ileostomy for diversion, and these can be reversed via a small incision that encircles the prior ostomy. The loop is then stapled back together and the incision is either loosely closed or left open to prevent a wound infection.
While ileostomies are again a nuisance, they are extremely beneficial in that they help prevent the dreaded complication of anastomotic leak. Anastomotic leaks can be life threatening and when they occur, they are almost always treated with a diverting ileostomy. Sometimes anastomotic leaks can lead to complications like rectal stricture that then require a permanent colostomy. So while you may be justifiably disappointed at the potential of requiring a temporary ileostomy, try to remember that it is being created to provide you with the best chance of healing from your LAR.
In the end, it is appropriate to be concerned about the potential of an ostomy during your rectal surgery. Be sure to have a discussion with your surgeon about the possibility of an ostomy during your preoperative office visits. Additionally, you should make an effort to meet with an enterostomal nurse who specializes in stoma appliances so that he/she may help you situate your ostomy in an ideal location and help you find the appliances that work best for you.
In patients with active UC for longer than 10 years, there is an increased risk of colorectal cancers. While some patients choose to be followed by serial colonoscopies and frequent biopsies to assess for changes consistent with cancer, surgery is a means of prophylaxis (prevention) against colorectal cancers. In patients with UC, the entire colon and rectum is at risk for malignancy, and therefore the recommended procedure is removal of the entire colon and rectum along with the creation of neo-rectum using small bowel. This procedure is known as a total proctocolectomy with ileal-pouch anal anastomosis (IPAA), or J-pouch.
Prior to undergoing a total proctocolectomy with IPAA, your surgeon will want you to be medically optimized for the procedure. This may require the administration of some supplemental nutrition, either via a feeding tube or intravenously. Some patients may need bowel preparations, although they are not routinely used as most patients with UC suffer from profound diarrhea. Lastly, most surgeons will perform a staged procedure in which a diverting ileostomy is created to allow the IPAA to heal properly, and therefore you should meet with an enterostomal nurse to mark your stoma site preoperatively.
The procedure begins with the removal of the entire colon and rectum. This can be done via an open technique with a midline incision, or can be laparoscopically assisted. The rectal portion of the surgery is similar to the rectal surgery performed for LAR, in that the rectal dissection is carried down from the abdominal compartment towards the pelvic floor. There is no perineal incision during this procedure, and the sphincter complex remains intact to allow for controlled defecation postoperatively.
Once the entire colon and rectum has been removed, the J-pouch is then created and brought down into the pelvis. From there, the pouch is connected to the anal canal using via either a stapled or hand-sewn anastomosis (See Figures 6 and 7). The majority of surgeons prefer to create a proximal diverting loop-ileostomy to allow this anastomosis to heal without the continuous presence of fecal material. This in turn requires a future operation to reverse the ileostomy, which is similar to the procedure described above. The wounds are then irrigated and closed and the patient is awakened from their general anesthesia.
Figure 7 – Completed IPAA
Complications from the procedure are similar to other surgeries on the colon and the rectum and include infectious complications, such as wound infection and urinary tract infection, deep venous thrombosis, hemorrhage, and anastomotic leak. One late complication specific to pouches is pouchitis, or inflammation of the pouch. This is believed to be caused by bacterial overgrowth as well as a number of other factors. Initially, pouchitis can be treated with antibiotics, but if the attacks increase in severity or frequency, then it may require the construction of an ileostomy in order to divert the fecal stream. Overall, total proctocolectomy with IPAA is a well-tolerated procedure and should be discussed with patients whose UC has been present longer than ten years.
IV. Surgery for Rectal Prolapse
Rectal prolapse is a condition where either a portion of the rectum or the entire rectum protrudes out from the anus. It is often associated with chronic constipation and straining during bowel movements, and is more common in females than males. Rectal prolapse initially presents as a mass protruding from the anus and is often mistaken for hemorrhoids on routine physical exams. There are several different types of disorders of defecation that can be addressed surgically including:
- Mucosal rectal prolapse
- Full thickness rectal prolapse (Procidentia)
- Paradoxic Puborectalis
- Internal Rectal Intussusception
- Abdominal Approach
- Suture Rectopexy
- Sigmoid Resection and Suture Rectopexy
- Perineal Approach
- Delorme Procedure
- Perineal Rectosigmoidectomy
Each procedure has its own specific indications and recurrence rates. In general, the abdominal procedures involve the repair of the loose rectal attachments to fix the rectum in place, while the perineal approaches address the redundant mucosa of rectum. Recurrence rates are lower for abdominal approaches than perineal approaches, but the perineal procedures are better tolerated by high-risk patients.
Abdominal Approach
Perineal Approach
The Delorme procedure is ideal for the treatment of mucosal rectal prolapse. It can be done under spinal, epidural, or even local anesthesia, and the patient can be positioned either facedown or face-up with their legs elevated in stirrups. The procedure basically involves a resection of the redundant portion of rectal mucosa as a full sleeve of tissue. The underlying muscle is then folded up like an accordion and sutured in place in what is referred to as a placation. At this point the mucosa is reconnected and the procedure is completed. Complications include bleeding, recurrent prolapse, and urinary retention. As there is no complete resection of the bowel, there are fewer infectious complications associated with the Delorme procedure.
Perineal Rectosigmoidectomy (removal of the rectum and part of the sigmoid colon) involves the full-thickness resection of the redundant rectum through the perineum. The procedure can again be performed under spinal or epidural anesthesia with the patient either face-up or facedown. Once the patient is positioned properly, the rectum is prolapsed, and a circumferential, full-thickness incision is made just above the line that demarcates the point where the rectum transitions into the anus. The rectum is then continually prolapsed and its blood supply is ligated (tied off) until the redundant bowel can no longer be pulled out any further. At this point, another full-thickness, circumferential incision is made in the bowel and the two ends are reconnected either via a stapled or hand-sewn anastomosis. Perineal rectosigmoidectomies have similar complications to the Delorme procedure, but also carry a risk of anastomotic leak and pelvic and intra-abdominal abscess, as there is a connection between two ends of the bowel that can potentially separate.
As you can see, there are a variety of choices for repair of your rectal prolapse, and it is important to have a lengthy discussion with a colon and rectal surgeon in order to determine which procedure is the ideal treatment for you.
Referenties
- Jemal A, Siegel R, Ward E, Murray T, Xu J, Thun MJ. Cancer statistics, 2007. CA Cancer J Clin 2007;57(1):43-66.
- Nelson H, Petrelli N, Carlin A, et al. Guidelines 2000 for colon and rectal cancer surgery. J Natl Cancer Inst 2001;93(8):583-96.
- Wolmark N, Fisher B. An analysis of survival and treatment failure following abdominoperineal and sphincter-saving resection in Dukes' B and C rectal carcinoma. A report of the NSABP clinical trials. National Surgical Adjuvant Breast and Bowel Project. Ann Surg 1986;204(4):480-9.
- Heald RJ, Ryall RD. Recurrence and survival after total mesorectal excision for rectal cancer. Lancet 1986;1(8496):1479-82
. - Adam IJ, Mohamdee MO, Martin IG, et al. Role of circumferential margin involvement in the local recurrence of rectal cancer. Lancet 1994;344(8924):707-1
1. - Cawthorn SJ, Parums DV, Gibbs NM, et al. Extent of mesorectal spread and involvement of lateral resection margin as prognostic factors after surgery for rectal cancer. Lancet 1990;335(8697):1055-
9. - Enker WE, Thaler HT, Cranor ML, Polyak T. Total mesorectal excision in the operative treatment of carcinoma of the rectum. J Am Coll Surg 1995;181(4):335-46.
- Wibe A, Moller B, Norstein J, et al. A national strategic change in treatment policy for rectal cancer--implementati
on of total mesorectal excision as routine treatment in Norway. A national audit. Dis Colon Rectum 2002;45(7):857-66. - Havenga K, Enker WE, McDermott K, Cohen AM, Minsky BD, Guillem J. Male and female sexual and urinary function after total mesorectal excision with autonomic nerve preservation for carcinoma of the rectum. J Am Coll Surg 1996;182(6):495-502.
- Maas CP, Moriya Y, Steup WH, Klein Kranenbarg E, van de Velde CJ. A prospective study on radical and nerve-preserving surgery for rectal cancer in the Netherlands. Eur J Surg Oncol 2000;26(8):751-7.
- Leung KL, Kwok SP, Lau WY, et al. Laparoscopic-assiste
d abdominoperineal resection for low rectal adenocarcinoma. Surg Endosc 2000;14(1):67-70. - Bleday R, Breen E, Jessup JM, Burgess A, Sentovich SM, Steele G, Jr. Prospective evaluation of local excision for small rectal cancers. Dis Colon Rectum 1997;40(4):388-92.
- Ota DM. M.D. Anderson Cancer Center Experience with Local Excision and Multimodality Therapy for Rectal Cancer. Surg Oncol Clin N Am 1992;1(1):147-152.
- Paty PB, Nash GM, Baron P, et al. Long-term results of local excision for rectal cancer. Ann Surg 2002;236(4):522-29; discussion 529-30.
- Steele GD, Jr., Herndon JE, Bleday R, et al. Sphincter-sparing treatment for distal rectal adenocarcinoma. Ann Surg Oncol 1999;6(5):433-41.
- Azimuddin K, Riether RD, Stasik JJ, Rosen L, Khubchandani IT, Reed JF, 3rd. Transanal endoscopic microsurgery for excision of rectal lesions: technique and initial results. Surg Laparosc Endosc Percutan Tech 2000;10(6):372-8.
- de Graaf EJ, Doornebosch PG, Stassen LP, Debets JM, Tetteroo GW, Hop WC. Transanal endoscopic microsurgery for rectal cancer. Eur J Cancer 2002;38(7):904-10.
- Farmer KC, Wale R, Winnett J, Cunningham I, Grossberg P, Polglase A. Transanal endoscopic microsurgery: the first 50 cases. ANZ J Surg 2002;72(12):854-6.
- Lezoche E, Guerrieri M, Paganini AM, Feliciotti F. Long-term results of patients with pT2 rectal cancer treated with radiotherapy and transanal endoscopic microsurgical excision. World J Surg 2002;26(9):1170-4.
- Williams NS, Johnston D. The quality of life after rectal excision for low rectal cancer. Br J Surg 1983;70(8):460-2.
- MacRae HM, McLeod RS, Cohen Z, O'Connor BI, Ton EN. Risk factors for pelvic pouch failure. Dis Colon Rectum 1997;40(3):257-62.
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