Total Colectomy and Ileorectal Anastomosis



Total Colectomy and Ileorectal Anastomosis


Steven Wexner

Sowsan Rasheid



Introduction

Total colectomy (sometimes referred to as subtotal colectomy) is the removal of the entire colon and preservation of the rectum. Intestinal continuity is restored by ileorectal anastomosis, also known as ileoproctostomy or ileorectostomy.

The role of total colectomy and ileorectal anastomosis in the treatment of colonic pathology is being redefined as the understanding of these different surgical pathologies is becoming more elucidated. Total colectomy has been replaced by total proctocolectomy with ileoanal J-pouch reconstruction as the surgical approach for treatment of ulcerative colitis. Previously, total colectomy with ileorectal anastomosis was undertaken for patients who had ulcerative colitis with “rectal sparing.” It is now agreed that this “rectal sparing” may result from the therapeutic enemas used in treatment of the disease and that rectal involvement is quite common. There is still a subset of ulcerative colitis patients who may benefit from the total colectomy approach, particularly young males who are reluctant to undergo a surgical procedure fraught with the risk of sexual dysfunction.

Patients with Crohn’s disease will sometimes require a total colectomy and patients with the attenuated form of familial adenomatous polyposis (FAP) syndrome are also candidates for a total colectomy as the rectum may not be involved by the polyposis. Other patients with neoplastic disease such as hereditary nonpolyposis coli carcinoma syndromes or even sporadic colon cancers may benefit from total colectomy and surveillance of the remaining rectum.

Total colectomy may be performed either prophylactically or for the treatment of an already diagnosed neoplasm. The clinical condition of the patient sometimes determines the need for proceeding with total colectomy. Patients with a lower gastrointestinal hemorrhage that is localized to the colon sometimes require a colectomy as a last resort for treatment of their bleeding. Patients with ischemic or infectious colitis may also require a total colectomy. This procedure is sometimes done on an emergency basis.

There are two surgical approaches for total resection of the colon: open and laparoscopic. Traditionally, the open technique has been utilized for colonic resection; however, as advances in laparoscopic surgery have been made more patients are undergoing laparoscopic colectomies. The colonic mobilization is usually laparoscopically undertaken. Once the colon is ready for removal a very small incision is made to exteriorize the colon and transect it at the rectosigmoid junction followed by creation of the ileorectal anastomosis.

The surgeon my elect not to perform an ileorectal anastomosis at the time of total colectomy based on the patient’s overall health and/or clinical condition. In patients who have poor continence or those who may be too hemodynamically unstable or suffering from a severe inflammatory process it may be prudent not to perform an anastomosis at the time of primary resection. Patients who require a total colectomy but have incontinence to stool would likely benefit from having a permanent ileostomy. Other patients who have fulminant colitis
with severe anemia, leucopenia or leukocytosis, malnutrition, and severe concomitant systemic diseases are better approached by a multistaged procedure. In performing a multistaged procedure the construction of the ileorectal anastomosis is delayed, the rectal stump is closed, and an end ileostomy is created. Alternatively, the proximal aspect of the distal stump may be exteriorized as a mucous fistula particularly if the rectum is involved by severe inflammation or infection such as in Clostridium difficile colitis. Regardless of the choice of either open mucus fistula or closed Hartmann’s stump, the presacral space should be left undisturbed. Violation of the presacral space at the initial operation significantly increases the difficulty of subsequent rectal mobilization and accordingly presacral hemorrhage and injury to the sympathetic and parasympathetic nerves.


Indications for Total Colectomy with Ileorectal Anastomosis


Colitis

Total colectomy with ileorectal anastomosis is seldom the best procedure for definitive management of ulcerative colitis as rectal involvement is quite common in ulcerative colitis and is often severe. Rectal “sparing” raises the specter of Crohn’s disease or may be due to enema therapy. Surgical management of this disease is best accomplished by restorative proctocolectomy with ileoanal J-pouch reconstruction. Some patients present with a toxic megacolon or toxic colitis or a severe exacerbation of their disease that is unresponsive to high dose steroids and other pharmacologic agents. This group of patients who tend to be critically ill may be best managed by a total colectomy and ileostomy. In this setting an end ileostomy is the most appropriate and safe choice for an unstable or a critically ill patient. Again, care must be taken not to open the presacral space.

Concerns of male sexual dysfunction and of infertility in females can present as quite profound anxiety about the possibility of sexual and/or reproductive dysfunction that could result from damage to the hypogastric nerves or nervi ergenti during rectal dissection. In some situations, proctectomy may be delayed while the remaining rectum is regularly surveyed with endoscopy and aggressively treated with local therapies such as enemas and possibly systemic therapies as well.

Crohn’s colitis may worsen despite aggressive medical management and bowel rest and thus requires total colectomy. Colonic strictures and fistulae are other complications of Crohn’s disease for which a total colectomy may be required. Patients’ medical conditions may vary along the spectrum of nutritionally replete to profoundly malnourished and markedly immune suppressed. The multiple medical therapies instituted to treat these patients such as steroids and immune modulatory drugs exacerbate immune dysfunction and are detrimental to wound and anastomotic healing. In addition, the disease commonly involves the rectum and anus, which may severely compromise both rectal and anal sphincter functions and thus continence. It is therefore necessary to carefully assess the anorectal aspects of Crohn’s disease during the history and physical examination. Inspection for anal fissures, skin tags, and fistulae, as well as digital examination to evaluate resting and squeeze tone and the presence of any stenosis is mandatory. Anorectal manometric studies can be helpful in objectively quantifying anal sphincter function and rectal compliance. Examination of the rectum with flexible sigmoidoscopy is also important in assessing the extent of involvement of the rectum by inflammation or scarring. Distensibility can also be judged by insufflation of air through the sigmoidoscope. If the rectum is found to be nondistensible due to severe involvement by Crohn’s disease it is best to either remove it during the planned surgical intervention or leave it in situ but without performing an ileorectal anastomosis at the time of surgery.

Patients with a history of abscess or fistula should be carefully examined and the extent and complexity of any fistulous tracts should be documented. Any abscess or fistula should be treated prior to consideration of an ileorectal anastomosis. It may be necessary for the patient to undergo a total colectomy with an ileostomy after which resolution of anorectal sepsis or fistula may permit construction of ileorectal anastomosis. If a patient had undergone a prior fistulatomy causing damage to the anal sphincters an ileorectal anastomosis may be contraindicated as patient’s poor continence may not be capable of controlling the resultant diarrhea following an ileorectal anastomosis. This assessment includes quantification of an incontinence score as well as anal ultrasonography and possibly also anal electromyography with bilateral pudendal nerve terminal motor latency evaluation.

Many patients with Crohn’s disease without anorectal disease or sphincter damage may be well adjusted and tolerant of diarrheal bowel movements. These individuals may be willing to live with mild to moderate diarrhea following an ileorectal anastomosis rather than having an ileostomy. Unfortunately, the risk of subsequent proctectomy and end ileostomy due to progression of Crohn’s disease and/or rectal dysfunction may be as high as 60% to 70%.

Ten percent to fifteen percent of patients present with colitis of unclear etiology known as indeterminate colitis. These patients tend to have a clinical course similar to that of ulcerative colitis may be reasonable candidates for a restorative proctocolectomy and ileal anal J-pouch. Alternatively, these patients may benefit from total colectomy with ileorectal anastomosis. After removing the entire abdominal colon a larger specimen is now available for close pathologic examination to help make a definitive diagnosis. The patient’s clinical course is also closely followed as manifestations of Crohn’s disease may become more apparent upon removal of the colon. It is best to have all perianal issues resolved prior to construction of ileorectal anastomosis.


Neoplasia

Family history of colon cancer and advances in genetic testing has helped define three different risk groups for colorectal cancer. These three different neoplastic conditions are FAP, hereditary nonpolyposis colon cancer syndrome, and genetic mutations that lead to sporadic colon cancer. In addition, synchronous or metachronous colon cancers represent high-risk patients who should likely be managed by a total or completion colectomy with ileorectal anastomosis or possibly a restorative proctectomy with ileal pouch anal anastomosis.

FAP syndrome is characterized by the presence of hundreds to thousands of colonic and rectal polyps that if left untreated will eventually become cancerous. It is the second most common genetically inherited colon cancer condition and accounts for <1% of cases of colorectal cancers in the United States. This disorder is inherited in an autosomal dominant pattern with 100% penetrance. A germline mutation in the adenomatous polyposis coli (APC) gene, located on the long arm of chromosome 5, is responsible for the FAP phenotype. This mutation is inherited or may occur de novo in patients without any family history of FAP. The APC gene protein product has a multitude of functions, which involve tumor suppression, modulation of cellular adhesion, and migration. It is also responsible for maintenance of microtubular and
chromosomal stability as well as having a role in cell cycle control.

Patients having the APC mutation are usually asymptomatic, although, some young patients may present with nonspecific complaints of abdominal pain, diarrhea, or rectal bleeding. Identification of these patients at a young age is very important as phenotypic expression in the form of >100 colorectal polyps begins in early adolescence, at around age 16, followed by inevitable progression to cancer by age 40. In families suspected of having FAP, surveillance consisting of flexible sigmoidoscopy and genetic testing should begin early in the teen years. Once polyps are identified, patients should undergo colectomy to remove the risk of cancer. Patients with FAP who have rectal involvement by polyps require a restorative proctocolectomy.

The rectum is rarely found not to be involved by polyposis or it may contain a minimal amount of polyps and therefore can be spared by performing a total colectomy with ileorectal anastomosis. In these cases, the patient may be suffering from attenuated FAP or MUTYH-associated polyposis (MAP), both of which are variants of FAP. Patients with attenuated FAP suffer from APC gene mutation in regions different from the classical FAP syndrome. They are found to have <50 colonic polyps, which tend to be in proximal locations with minimal to no rectal involvement. The average age of onset of polyposis and colorectal cancer is later than seen in classic FAP, mid-30s and 50s, respectively. Approximately 10% to 20% of patients with FAP do not have the APC mutation but rather have MAP, which is an autosomal recessive condition characterized by mutations in the DNA repair gene known as MUTYH. These patients are difficult to distinguish from classic FAP patients but tend to have <100 polyps, which present at a much later time in life, usually by the fifth decade. Rectal involvement also tends to be minimal, and therefore like their attenuated FAP counterparts, these patients are usually good candidates for total colectomy and ileorectal anastomosis. Rectal preservation is advantageous to young patients as it limits the risk of compromised sexual function and carries less risk of incontinence. Spontaneous regression of rectal polyps following total colectomy and ileorectal anastomosis has been described in up to 50% to 64% of patients. Twenty percent to 38% of patients have complete resolution while 15% to 26% show partial resolution of the rectal polyps. It is thought that colectomy is responsible for causing regression and at times resolution of rectal polyps by decreasing rectal mucosal proliferation. The mechanism behind this decrease in mucosal proliferation is attributed to changes in the chemical composition of stool to which the rectum becomes exposed. Changes in the fecal flora, concentrations of primary bile acids, coprostanol, and reduction of carcinogenic factors have all been noted to occur following a total colectomy. These effects may be temporary or permanent but still do not prevent later redevelopment of polyps and subsequently cancer. Approximately 55% of patients who had initial regression are eventually found to have rectal polyps during long-term follow-up. Therefore, patients who undergo this procedure require regular sigmoidoscopic surveillance, which makes compliance a potential problem. Restorative proctocolectomy with ileal pouch-anal anastomosis remains the preferred procedure because it almost entirely eliminates the risk of cancer while preserving the anal sphincters.

Hereditary nonpolyposis colorectal cancer (HNPCC) is the most common genetically inherited colorectal cancer disorder, accounting for 2% to 5% of newly diagnosed colorectal cancers. Also known as Lynch syndrome after Dr. Henry Lynch who was one of the first to describe a familial group of colorectal cancers in association with endometrial and stomach tumors in 1966. Since then Lynch syndrome has been divided into Lynch I and II. Patients with Lynch I syndrome suffer from predominantly right-sided colorectal cancer without any other associated types of cancer, whereas those individuals with Lynch II have other cancers involving the GI and GU tracts in addition to colorectal cancer. Patients with Lynch II syndrome have 40% to 50% chance of developing endometrial carcinoma and a 12% chance of developing ovarian carcinoma. They are also at increased risk of having transitional cell carcinoma involving the ureters as well as other cancers involving the stomach, hepatobiliary system, and small intestines. The onset of cancer is usually earlier than in the general population with these patients presenting in their mid-40s as opposed to 60 to 65 years in patients with sporadic cancer.

Prior to identification of the genetic basis of this syndrome many criteria were used to identify these patients and their family members. The modified Amsterdam criteria is currently used to identify patients with HNPCC by evaluating their family history, which includes: (a) three or more relatives with histologically proven colorectal carcinoma, one of whom is a first-degree relative of the other two people; (b) colorectal carcinoma involving at least two generations; and (c) one or more cases of colorectal carcinoma diagnosed before the age of 50 years. Mutations in DNA-mismatch repair genes such as the most commonly affected MLH1, MSH2, and MSH6 are responsible for predisposition to cancer development over a patient’s lifetime. These mutations are inherited in an autosomal dominant pattern and lead to approximately an 80% disposition to subsequently developing colorectal cancer. Failure of DNA repair, due to defective mismatch repair proteins, during replication leads to development of microsatellite instability (MSI) in the DNA of colorectal cancer. This characteristic finding is often used as a marker for HNPCC as 90% of both cancerous lesions and polyps contain MSI in their DNA. The revised Bethesda criteria incorporates the findings of MSI in pathologic specimens and is another set of criteria that may be used to identify these patients: (a) colorectal carcinoma identified in a patient younger than 50 years of age; (b) synchronous or metachronous colorectal cancer or other HNPCC-associated cancer; (c) colorectal cancer with finding of MSI in pathologic specimens in patients younger than 60 years; (d) colorectal cancer or other HNPCC cancer in a first-degree relative with one of these cancers in a family member <50 years old; and (e) colorectal cancer in two or more first- or second-degree relatives along with HNPCC-associated tumors regardless of age. Despite the availability of genetic testing, it is not standard of care in identification of these patients and family history and the use of the above criteria remain important in making the diagnosis of HNPCC.

Patients known to have HNPCC or those having a family history of HNPCC should undergo regular endoscopic surveillance consisting of colonoscopy every 1 to 3 years starting at the age of 20 to 25 years or 5 to 10 years earlier than the age of the youngest relative diagnosed with colon cancer. The frequency of screening should increase to every 1 to 2 years after the age of 40. Since flexible sigmoidoscopy alone is not adequate as a screening method for these patients as most colon cancers tend to be proximal. A barium enema needs to be performed along with flexible sigmoidoscopy. The screening schedule and frequency remains the same. Extra-colonic screening of the endometrium and ovaries should also be done starting at age 30 to 35 years with including examinations, transvaginal ultrasound, and endometrial biopsy every 1 to 2 years. Patients with family history of other related extra-colonic neoplasms should undergo screening applicable to the organs in question such as the stomach and GU systems. The role of prophylactic colectomy in patients with HNPCC is debatable as it may cause 15% to 20% of patients who would not develop colon cancer due to
the incomplete penetrance of this disease to undergo unnecessary surgery. For patients who have already had a colon cancer associated with HNPCC, total colectomy with ileorectal anastomosis is the ideal procedure to eliminate their risk of subsequently developing a metachronous cancer in the remaining colon. Patients who refuse yearly colonoscopies or are poorly compliant may qualify for a prophylactic total colectomy with ileorectal anastomosis. Women who have a strong family history of endometrial cancer in association with HNPCC may also be candidates for prophylactic hysterectomy and salpingo oophorectomy. However, for any patient who undergoes total colectomy with ileorectal anastomosis in the setting of HNPCC, all must undergo yearly flexible sigmoidoscopies for surveillance of the rectum, which still has a 6% to 20% risk of developing cancer.

Colon cancer occurring due to sporadic mutations such as in the p53 gene may present as an obstructing cancer of the left colon with a dilated proximal colon, which is not suitable for a primary resection and anastomosis. These patients can be treated by total colectomy and ileorectal anastomosis although other alternatives are a staged approach or the use of on-the-table washout with primary colonic or colorectal anastomosis. Nonobstructing cancer of the distal transverse or proximal descending colon can be treated by total colectomy with ileorectal anastomosis. This procedure avoids anatomically awkward attempts to restore the continuity of the hepatic flexure to the sigmoid colon or rectum. In addition, it avoids the possibility of making an anastomosis in a watershed region of the colon.


Lower Gastrointestinal Hemorrhage

Severe bleeding from the colon can be massive and uncontrollable. Typically, these patients are elderly and their condition develops from hemorrhagic diverticulosis coli or angiodysplasia, also called an arterial venous malformation. Oftentimes, the hemorrhage spontaneously stops, possibly associated with the resultant hypotension. Fortunately, surgeons today are seldom faced with an operative decision in these patients. As with any bleeding patient resuscitation and stabilization is usually necessary. If bleeding continues, aggressive preoperative diagnostic evaluation, including colonoscopy, radionuclide scanning, and angiography, usually localizes the bleeding to a segment of the colon. Choice of localization modality is dependent upon many factors including patient stability, rate of bleeding, available institutional expertise and algorithms. Clinical resuscitation and selective nonoperative treatment usually controls the hemorrhage. Patients may receive selective embolization or selective vasopressin infusion of the distal colonic vessels. Colonoscopic investigation in the acute phase may be both diagnostic in terms of localization of the source and therapeutic in terms of its treatment. Therapeutic options include monopolar diathermy, bipolar electrocautery, laser coagulation, vasoconstrictor and/or sclerosant injection, and direct hemoclip placement. Unstable patients who fail medical therapy must undergo surgery. Intraoperative colonoscopy may assist in pinpointing the bleeding site and thus limits the resection to one segment. Patients rarely present with a primary hemorrhage or recurring episodes, with two possible sources (typically, angiodysplasias in the right colon and severe diverticulosis in the left colon). These patients are candidates for total colectomy to eliminate both potential sources of bleeding.


Chronic Constipation and Colonic Inertia

Severe chronic constipation refractory to vigorous medical management may be an indication for total colectomy with ileorectal anastomosis. These conditions are referred to as intestinal motility disorders. When the motility disorder resides within the colon, it is termed colonic inertia. Other conditions such as diabetes mellitus or collagen vascular disorders may manifest themselves as gastroparesis, small intestine motility dysfunction, or colonic inertia. Disorders in motility could be related to specialized neural ganglion in the intestine such as Meissner, Auerbach plexus, or the cells of Cajal. Small intestinal contrast imaging may demonstrate multiple, scattered true diverticula, which may represent sequelae of underlying panenteric motility disorder.

The most important aspect of evaluation of colonic inertia is physiologic investigation.

Colonic motility is assessed with the use of radiopaque markers while gastric emptying is evaluated with scintigraphy and small-bowel motility most easily examined by a lactulose breath hydrogen transit study. It is important to distinguish isolated colonic inertia from panenteric dysmotility. While patients with inertia may potentially benefit from a colectomy, patients with panenteric dysmotility will not. In addition to exclusion of upper intestinal dysfunction, pelvic floor dysfunction must be excluded. Anorectal functional assessment includes cinedefecography, anal electromyography, and anal manometry to evaluate rectal function and to exclude pelvic outlet dysfunctions such as nonrelaxing puborectalis syndrome. Patient selection for functional disorders is a vital part of the surgical decision. Potential candidates for total colectomy with ileorectal anastomosis should have isolated colonic inertia, without gastric or small bowel dysmotility and with normal pelvic floor function.


Surgical Technique


Open Resection

Although total colectomy certainly can be accomplished with the patient supine, the lithotomy position has the advantage of access to the anus for intraoperative colonoscopy or sigmoidoscopy, for stapling, and for inspection of the anastomosis for integrity. Proper positioning should include placement of intermittent compression stocking or other means for deep venous thrombosis prevention; compression stockings may also assist in preventing sural nerve damage. With the patient in heel and calf stirrups, the rectum can be examined and a triple-lumen irrigation catheter is positioned for use with rectal irrigation with a balanced salt solution before skin preparation and draping.

The positions of the surgical team depend on the experience and the anticipated role of the assistants. If the first assistant is capable of dissection under guidance, it is advantageous for the surgeon to stand on the patient’s left side. The surgeon thus has control of retraction and exposure of the right and transverse colon. The description of technique here assumes this arrangement. When the left colon is dissected, the assistant retracts with one hand and dissects with the other while the surgeon laterally displays the tissues to be incised. In a teaching setting, there is sometimes a shifting of positions around the table.

A midline incision is standard for gaining access to the peritoneal cavity to perform a colectomy. A transverse incision below the umbilicus is a possible approach for slender patients or patients with a long-standing inflammatory bowel disease, which often leads to a shortened colon and mesocolon. Some surgeons prefer a transverse incision with the thought that it lowers the incidence of incisional hernias. However, transverse incisions can be too low and they will not always facilitate splenic mobilization.

After inspection of the abdomen, mobilization of the colon begins on the right side. The surgeon retracts the colon medially being careful to protect the bowel from injury and an incision is made in the peritoneal reflection lateral to the cecum. The peritoneal incision is made close to the cecum to expose the retroperitoneal avascular
plane and facilitate dissection of the right colon from its posterior attachments. Electrocautery is usually used to accomplish this incision and minimize bleeding from small peritoneal vessels, but scissors can be used as well. Once the lateral peritoneal reflection is opened, the surgeon inserts the left index finger into the defect; retracting the cecum and right colon more medially as the lateral peritoneum is incised further cephalad (Fig. 1). The peritoneal incision should be made close to the colon so as not to unnecessarily expose Gerota’s fascia by overly lateral dissection. As the dissection proceeds immediately adjacent to the mesocolon, the gonadal vessels and the right ureter will be exposed in the retroperitoneum; the ureter should remain untouched in the retroperitoneum.

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Aug 2, 2016 | Posted by in GENERAL SURGERY | Comments Off on Total Colectomy and Ileorectal Anastomosis
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