Scientific American Surgery DOI 10.2310/7800.2089

08/15

© 2015 Decker Intellectual Properties Inc

gastrointestinal tract and abdomen

O P E R A T I O N S F O R C O L O N C A N C E R

Kevork Kazanjian, MD, FACS, and David A. Etzioni, MD, MSHS, FACS*

Colon cancer continues to be a disease of significant burden worldwide. In the United States, it is the third most com­monly diagnosed cancer and cause of cancer death. In 2013, 102,480 new diagnoses of colon cancer are expected in the United States, with an additional 40,340 new cases of rectal cancer.1 This is despite the overall declining incidence of 2 to 3% per year seen since 1998, thought to be due to the growing prevalence of colorectal cancer screening.2,3

The majority of patients diagnosed with colon cancer will benefit from a properly performed oncologic surgery, which typically involves a partial colectomy to achieve locore­gional control and establish the true stage of the cancer. Par­tial colectomy is one of the most commonly performed operations in the United States. With well over 250,000 colectomies performed annually, colon cancer is the most common indication.4,5 Patient outcomes from these opera­tions are increasingly scrutinized because of the consider­able morbidity and mortality associated with these procedures.6 Overall, morbidity after colectomy stands at 24%, with major morbidity occurring in 11% and mortality in 3%.7 Therefore, it is critical that general surgeons are adept in managing this disease and performing the appro­priate operation. In this review, we address the technical issues of safe and oncologically proper methods of colon cancer resection with appropriate preoperative planning and postoperative care involved in these important and commonly performed operations.

Indications for Surgery

In general, resection is the mainstay of therapy for all patients with nonmetastatic disease. A small minority of patients may not be candidates for surgical resection due to medical comorbidity. For patients with metastatic dis­ease, thorough consideration of the risks and benefits of resecting the primary tumor will determine the proper approach. Patients who are candidates for resection of meta static disease can usually undergo resection of the pri­mary tumor simultaneously. However, the majority of patients with unresectable metastatic disease, which deter­mines the prognosis, can have their primary colon tumor managed without surgery.8 Patients with endoscopically unresectable polyps that are histologically benign should be treated according to the same oncologic principles as patients with colon cancer. There is a dual rationale for this seemingly aggressive approach. First, there is a distinct likelihood that the polyp may harbor an undiagnosed car­cinoma. This risk of carcinoma is approximately 17%, and polyps with dysplasia on histology from endoscopic biopsy

or those that are left sided are at greater risk for containing cancer.9 The risk is not necessarily proportional to polyp size, as previously reported.10–12 Second, there is a distinct but unquantifiable risk that the polyp will degenerate into a malignant lesion over time.

When a malignant polyp is identified after endoscopic polypectomy, it should be considered an indication for colectomy unless specific criteria are met: (1) pathologic evaluation confirms at least a 2 mm margin and (2) absence of any unfavorable histologic features, such as poor differ­entiation, lymphovascular invasion, or extensive budding. The cancer should also be limited to the superficial submu­cosal layer (SM1 or SM2).13,14 When unfavorable histologic features are present, even when the malignant polyp is ade­quately excised, the risk of nodal metastasis rises, requiring an oncologic resection even in the absence of residual disease in the bowel wall.

Preoperative Planning

Preoperative planning of an operation for a patient with colon cancer includes the need for the surgeon to under­stand as best as possible the location of the tumor in the colon, the clinical stage of the cancer, and the patient’s phys­iologic status and risk factors. The informed consent process should always include a discussion of the minor and major complications of a major abdominal operation, including the infrequent but dreaded complication of anastomotic leak and possible need for temporary ostomy, either at the time of surgery or as a result of postoperative complication.

colonoscopy

It is imperative that a patient with a colon cancer diagno­sis have a preoperative complete endoscopic evaluation of the colon whenever technically feasible. A patient who has a neoplastic process in one segment of the colon has greater risk in other segments. A study of patients with obstructing colon cancers demonstrated a 58% synchronous adenoma rate and a 6% synchronous cancer rate.15

Endoscopic tattooing of the tumor site should be per­formed routinely with submucosal injection except in situ­ations where localization is straightforward due to the tumor being within constant anatomic landmarks, such as the ileocecal valve, or the tumor is large and can be local­ized on a computed tomographic (CT) scan. Preoperative endoscopic tattooing is especially critical when dealing with the site of a malignant polyp that was removed endo­scopically with positive margins. In these cases, the patient should undergo a second endoscopy to ink the polypec­tomy site as soon as the endoscopist learns of the malig­nant diagnosis, before the polypectomy site heals and becomes impossible to localize. This tattoo is important regardless of whether or not a colon resection is planned.

* The authors and editors gratefully acknowledge the contribu­tions of the previous author, Noelle L. Bertelson, MD, to the development and writing of this review.

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Even if a colectomy is not performed, the tattoo will facili­tate future surveillance endoscopy.

endoscopic stenting

When a patient presents with a distal colonic obstruction due to a colon cancer, endoscopic stents can often be a valu­able tool to convert an emergency operation to a controlled semielective one. Although there are pitfalls such as perfo­ration, stenting can be an excellent bridge to resection or as palliation to relieve obstruction in patients with advanced metastatic disease who are not fit for surgery or have a very limited prognosis.16 Patients who are candidates for curative surgery can benefit from preoperative stent placement. In select cases, stents can facilitate primary anastomosis and avoid the need for ostomy formation by allowing normaliza­tion of bowel integrity. In addition, this allows time for pre­operative physiologic optimization of the patient. Successful stent deployment and subsequent definitive resection after about 7 days of decompression can be achieved in approxi­mately 70% of patients.17,18

Stenting as a bridge to resection is generally not useful in patients with colonic obstructions proximal to the splenic flexure as these lesions are best treated with a right hemico­lectomy or extended right hemicolectomy. These types of resection involve an anastomosis between ileum and colon distal to the site of obstruction and therefore are not facili­tated by decompression.

computed tomography

Contrast­enhanced CT scanning of the chest/abdomen/pelvis is the recommended initial staging study for colon cancer.19 Patients found to have unresectable hepatic metas­tases or those replacing more than 50% of the hepatic paren­chyma should be referred for systemic therapy as the risks of hepatic failure and mortality are high in these patients.20 When resectable or borderline resectable liver metastases are identified, a multidisciplinary decision should be made on the sequence of treatment. The options include simulta­neous liver and colon resection followed by systemic chemo­therapy or upfront chemotherapy followed by simultaneous versus staged liver and colon resection.21,22 CT imaging that identifies invasion of the tumor into adjacent structures such as the duodenum or bladder may also alter the surgical plan, possibly necessitating the involvement of multiple surgical disciplines. CT combined with positron emission tomogra­phy (PET) is not recommended for initial staging in lieu of a contrast­enhanced CT scan but may be useful in the eval­uation of indeterminate findings or in the setting where recurrence is suspected.23

genetic testing

Although a review of the ever­expanding role of genetic analysis in surveillance and personalized treatment plan­ning for colon cancer patients is beyond the scope of this review, its role in preoperative planning is worth noting. Hereditary colorectal cancer syndromes are thought to account for up to 10% of all colorectal cancers, with another 20% having a familial predilection for colorectal cancer without a clear genetic footprint being identified.24

Hereditary colorectal cancer syndromes can be divided into those associated with colonic polyposis (e.g., familial adenomatous polyposis [FAP]) and those not associated with colonic polyposis (e.g., hereditary nonpolyposis colon cancer [HNPCC]). The decision to initiate genetic testing and counseling for a patient with colon cancer diagnosed in the setting of polyposis is intuitive. Such a decision is more difficult when polyposis is not present; therefore, selecting which patients should be tested for HNPCC requires consid­eration of a number of clinical features, including personal and family history as well as morphologic features of the tumor(s). Germline mutations in the mismatch repair (MMR) genes MLH1 and MSH2 are responsible for the majority of cases of HNPCC, followed by MMR mutations in MSH6, PMS2, and EPCAM. Individuals with HNPCC have an 80% lifetime risk of colon cancer, with a predominance of cancers proximal to the splenic flexure (68% HNPCC versus 49% sporadic cases) and a higher incidence of synchronous can­cer (7% HNPCC versus 1% sporadic cases) and metachro­nous cancer (29% HNPCC versus 5% sporadic cases).

The propensity for development of a metachronous cancer after resection of the index cancer is the basis for the patient with HNPCC to consider a total abdominal colectomy with ileorectal anastomosis with subsequent annual proctoscopy over a partial colectomy. If this is not undertaken, the patient with HNPCC should be advised to undergo surveillance with annual colonoscopy.

Mounting evidence suggests that there will likely come a time when all patients with colon cancer are offered some form of genetic testing, but a “test all” approach is not yet practical or cost­effective.25,26 Therefore, a selective approach is generally recommended. For a patient with colon cancer diagnosed at under 50 years of age or a patient with colon cancer over 50 years of age with a first­degree relative with HNPCC­related cancer under 50 years or adenoma at under 40 years, it is reasonable to directly proceed with germline testing for mutations in MMR genes. When the clinical risk is lower, microsatellite instability (MSI) testing of the tumor sample should be performed first. If the tumor is microsat­ellite stable (MSS) or MSI­low, it is reasonable not to per­form any further genetic testing. If the tumor is MSI­high, MMR gene sequencing is performed and the patient coun­seled according to the results.

bowel preparation

The role of preoperative mechanical bowel preparation in patients undergoing colectomy has been a topic of debate over the past decade. Patients have traditionally been required to undergo preoperative mechanical bowel prepa­ration with the belief that it would reduce the risks of surgi­cal site infection and anastomotic leak. We now know that the risk of overall complications is similar regardless of whether mechanical bowel preparation was performed and the prac­tice of mandatory bowel preparation of the past was largely unnecessary. However, there are some differences in indi­vidual complications, with a lower risk of intra­abdominal abscess and higher surgical site infection rates in patients who undergo preparation.27,28 These findings have sup­ported the omission of bowel preparation in enhanced recovery after surgery pathways to minimize the fluid shifts

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of bowel preparation that may result in delayed return of bowel function.29,30

Currently, bowel preparation is best considered discre­tionary. Apart from the mixed effect of bowel preparation on patient outcomes, there are a number of situations in which bowel preparation has practical utility. A prepared colon will allow for intraoperative colonoscopy if the loca­tion of a tumor is ever in question. Also, when performing laparoscopic colon surgery, a colon that is distended with solid stool can be very difficult to manipulate and exterior­ize, thereby compromising the surgeon’s ability to offer patients a minimally invasive operation. This is especially true when a left­sided colon resection is required.

stoma marking

Very few patients with colon cancer require a stoma. However, in situations when a stoma is contemplated or possible (e.g., obstruction, perforation, or immunocompro­mised state), preoperative marking of the stoma site is strongly advised. There are significantly fewer stoma­ related complications in patients who have been marked for a stoma site preoperatively.31 Stoma marking and education are typically done by a certified enterostomal therapy nurse, but if one is not available, the surgeon should mark the site preoperatively according to a few basic principles. This includes choosing a site over the rectus muscle that is flat and visible to the patient in the sitting and standing posi­tions and avoiding the creases of abdominal folds as these will lead to difficulty with pouching of the stoma with an appliance. In morbidly obese patients, placing the stoma through the rectus on the upper abdomen (where the abdominal wall is thinner) is a safe strategy.

deep vein thrombosis prophylaxis

Patients with cancer have an increased risk of deep vein thrombosis (DVT) and pulmonary embolism (PE). This risk is intensified with the addition of major abdominal surgery and is a major contributor to mortality after surgery for colon cancer. Without prophylaxis, the risk of DVT is as high as 30%.32 Patients undergoing surgery for colon cancer should receive a preoperative dose of subcutaneous heparin followed by postoperative heparin three times daily, as well as sequential compression devices and early mobilization.33 Pharmacologic prophylaxis regimens have not been associ­ated with any significantly increased risk of bleeding.34

preoperative antibiotics

Current guidelines under the Surgical Care Improvement Project include perioperative antibiotic (e.g., ertapenem) started within 1 hour of incision, usually as a single dose but not to exceed 24 hours of therapy if redosed. Surgical site hair should be clipped rather than shaved. Urinary catheters should be removed by postoperative day 2 unless there is a specific indication such as urinary retention, and normother­mia should be maintained perioperativel y.35

preoperative ureteral stenting

The intimate association of both ureters with the colon makes them vulnerable structures to injury that may lead to significant morbidity. A thorough understanding of anat­omy and meticulous dissection and identification of the

ureters should keep them safe in routine cases. However, in the setting of bulky tumors, recurrent cancer cases, or expected inflammatory disease in the rectosigmoid or cecum that may distort anatomy, ureteral stents can be very useful.36 Ureteral stents offer a means for both visualization and palpation of the ureters. A selective approach to uret­eral stenting in complex cases should not require a signifi­cant amount of additional time at the start of surgery, can save a significant amount of time, and provides reassurance during surgery in the setting of troublesome anatomy while being at least cost neutral.37,38

Technical Considerations

laparoscopic versus open surgery

The safety of laparoscopic surgery for colon cancer is now widely accepted and is gradually becoming the standard of care for the majority of cases.39,40 Laparoscopic colectomy has been shown to have short­term advantages over open colec­tomy in terms of earlier return of bowel function leading to shorter hospital stay (1 or 2 days); reduced postoperative pain, narcotic use, and complication rates; and improved quality of life in the initial postoperative period.41–47 Analy­ses of cost also favor laparoscopic colectomy because the greater expense of the surgical instruments and longer oper­ating times are outweighed by the savings incurred by a shorter hospital stay.46–48 Laparoscopic colectomy also pro­vides the advantage of cosmetic results and body image per­ception, although long­term quality of life is similar. The value of the reduced surgical site complications in colon cancer patients is probably understated, especially for patients who receive adjuvant chemotherapy as wound complications can delay initiation of systemic therapy. The multicenter prospective randomized trials carried out by the COST, CLASICC, and COLOR study groups showed that survival, recurrence, and complications were not signifi­cantly different between laparoscopic and open approaches over long­term follow­up.41,49,50

The decision of whether to pursue a laparoscopic or open operation for a patient with colon cancer should be deter­mined by both patient factors and surgeon factors. Some patients are not good candidates for laparoscopic surgery. It is also expected that some tumors are not appropriate for a laparoscopic approach. In fact, the most common indication for conversion from laparoscopic to open surgery in the COST trial was tumor­related factors. It is critical that the quality of the surgery is not compromised for the sake of performing the operation laparoscopically. When all else is equal, a laparoscopic approach is probably preferable, but it is important that surgeons are aware of their skill and expe­rience and remember that a well­performed open surgery is superior to a poorly performed laparoscopic one.

oncologic considerations

The key to a proper oncologic resection for a colon can­cer requires clear margins, resection of the locoregional lymph node–bearing mesentery for both cure and accurate staging, and fashioning of an air­tight, tension­free, and well­vascularized anastomosis. In general, a proximal and distal margin of at least 5 cm from the tumor is considered

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appropriate, although additional length of resection is often required as determined by the vascular supply to the colon segment. The proximal and distal margins are usually eas­ily obtained when an adequate mesenteric resection is per­formed. When a colon cancer has invaded locally into surrounding structures such as small bowel, duodenum, or bladder, an en bloc resection should be planned.

Once the tumor and its associated mesentery are resected, a large portion of the pathologic evaluation of the speci­men is focused on evaluation for nodal metastases. The correlation between the number of lymph nodes analyzed and the patient’s oncologic outcomes has been an area of extensive study. Numerous studies have shown an improve­ment in disease­specific and overall survival when increas­ing numbers of lymph nodes are examined for stage II and stage III colon cancer.51–53 In fact, consensus guidelines have suggested that examination of 12 regional lymph nodes is a minimum for adequate nodal evaluation for colon can­cer.19 These have led to a belief that an adequate lymph node analysis is a measure of quality of care.54 The improve­ment in outcomes is probably due in part to stage migra­tion or more accurate staging that allows for increased use of adjuvant chemotherapy. The adequacy of lymph node examination for colon cancer may alternatively be a proxy for other factors that account for the improvement in out­comes, such as overall surgical technique, multimodality

therapy, and cancer surveillance activities.55 The sugges­tion that there is a direct therapeutic benefit from a more complete surgical lymphadenectomy and pathologic exam­ination is speculative at this point. Therefore, the focus should be on adhering to meticulous oncologic principles and techniques to produce high­quality patient outcomes rather than achieving a specific lymph node “count” as the target outcome.

As a general rule, the extent of resection in a colectomy should encompass one blood vessel proximal and one ves­sel distal to the tumor location in the colon [see Figure 1 and Figure 2]. Therefore, for tumors anywhere along the ascend­ing colon, a right hemicolectomy is required. This involves proximal resection of 5 to 10 cm of terminal ileum with liga­tion of the ileocolic pedicle origin and right branch of the middle colic vessels, with distal margin transection at the level of the proximal to midtransverse colon. A tumor at the hepatic flexure or transverse colon requires an extended right hemicolectomy, which involves ligation of the middle colic vessels at their origin rather than only the right branch of the middle colic vessel as in a standard right hemicolec­tomy. The distal margin of resection is at the distal trans­verse colon. A transverse colectomy is not appropriate oncologically for a transverse colon cancer unless limited surgery is being performed for palliation or the patient can­not tolerate more extensive surgery. Tumors in the distal

Figure 1 Vascular anatomy of the colon.

Middle Colic Artery

Right Colic Artery

Ileocolic Artery

Appendicular Artery

Superior Rectal Artery

Superior Mesenteric Artery

Inferior Mesenteric Artery

Left Colic Artery

Jejunal Artery

Ileal Artery

Sigmoidal Artery

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Figure 2 (a) Oncologic resection of cecal and ascending colon carcinoma. (b) Oncologic resection of hepatic flexure carcinoma, in which the distance between the tumor and the left branch of the middle colic vessels is greater than 10 cm. (c) Oncologic resection of proximal transverse colon carcinoma, in which the distance between the tumor and the left branch of the middle colic vessels is less than 10 cm. (d) Two options for resection of transverse colon carcinoma: transverse colectomy (A) and extended right hemicolectomy (A plus B). (e) Two options for resection of splenic flexure carcinoma: splenic flexure resection (A) and left hemicolectomy (A plus B). (f ) Oncologic resection of descending colon carcinoma. (g) Oncologic resection of sigmoid colon carcinoma.

10cm

A

a b c

d

g

e f

A

B

B

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transverse or splenic flexure require a left hemicolectomy with ligation of the left branche s of the middle colic vessels, inferior mesenteric vein (IMV), and left colic vessels. A sub­total colectomy from terminal ileum to descending colon may also be performed for tumors at or distal to the splenic flexure, particularly in the setting of an obstructing tumor, where the colon proximal to the tumor cannot be evaluated for synchronous disease. The surgical approach to cancers in the descending colon also requires a left hemicolectomy and should involve ligation of the left colic vessels at their roots with preservation of the superior rectal (hemor­rhoidal) artery, ligation of the IMV at the inferior border of the pancreas, and ligation of the arcade of vessels or left branch of the middle colic vessel at the proximal point of transection depending on the specific tumor location. A lesion in the sigmoid colon requires a high ligation of the inferior mesenteric artery (IMA) at its origin. High ligation of the IMV is usually performed to achieve adequate length for colorectal anastomosis. Once the specimen is completely removed, if the tumor is not obviously palpable, it is critical that the bowel is opened and examined to ensure that the pathology is adequately removed prior to proceeding with bowel anastomosis.

fundamentals of laparoscopic colon surgery

A successful laparoscopic colectomy requires a degree of planning that is often not part of an open colectomy. Patient positioning is critical in laparoscopic colectomy. For most laparoscopic operations, the patient is placed in the low lithotomy position to allow for a surgeon or assistant to stand between the legs as well as have access to the rectum for circular stapling devices and intraoperative endoscopy. Both arms should be carefully padded at all pressure points and tucked at the sides, with the hands well protected from the moving parts of the lower extremity stirrups. Specific attention should be given to securing the patient to the bed to avoid slipping during surgery. This can be achieved with the help of foam padding under the patient and placement of straps from the operating table across the patient’s chest. It is crucial for patients in the lithotomy position to have their knees in even profile with their torso to avoid collision of the laparoscopic instruments with the lower extremities. When the planned operation is a laparoscopic right hemico­lectomy for a definitively localized tumor and there is no risk of the need for intraoperative colonoscopy, positioning the patient supine with only the left arm tucked is an appropri­ate and simpler alternative. Once the patient is secured, this should be confirmed by tilting the table in all extreme posi­tions. Careful positioning will allow the patient to be placed safely in the deep Trendelenburg position, the reverse Tren­delenburg position, and lateral rotation, thereby allowing gravity to function as a retractor.

The choice of a straight laparoscopic approach versus a hand­assisted laparoscopic approach, especially in complex cases and the obese population, is largely a matter of sur­geon preference. The hand­assisted approach is rarely of significant benefit in right colectomy but can be very useful in expediting an operation or enabling a laparoscopic approach in left­sided or total colectomy. In a prospective randomized study, hand­assisted laparoscopic colectomy resulted in significantly shorter operative times and fewer

conversions while maintaining clinical outcomes similar to those of straight laparoscopic techniques for patients under­going left­sided colectomy and total abdominal colectomy.56 In most instances, an extraction site of approximately 3 to 5 cm in length will be required depending on the size of the specimen and the patient’s body habitus. This extraction incision is slightly larger (6 to 8 cm) when a hand­assisted approach is used. This extraction incision, which typically starts out as a working port, which is then enlarged for spec­imen removal, can be made around the umbilicus, the lower midline or Pfannenstiel, or at a planned ostomy site.

In open surgery, a colectomy can be performed effectively without the use of special energy delivery devices. In lapa­roscopic surgery, however, vessel­sealing energy devices have been revolutionary in easing some of the technical challenges surgeons would face without them. These include ultrasonic shears and bipolar sealing devices. The Harmonic Scalpel (Ethicon Endosurgery, Cincinnati, OH) is approved for sealing vessels up to 5 mm. The LigaSure (Covidien, Mansfield, MA) and EnSeal (Ethicon Endosurgery) are bipo­lar sealing devices that are effective for sealing vessels of up to 7 mm in diameter. All of the vascular pedicles that may need to be divided in a colectomy (ileocolic, middle cerebral artery, IMV, IMA) can usually be safely sealed with the EnSeal or LigaSure, making them currently the most com­monly used energy delivery devices in laparoscopic colec­tomy. Thermal spread does extend for 2 to 3 mm, however; therefore, care must be exercised when using these close to adjacent structures such as bowel to avoid inadvertent thermal injury.57–59 Lastly, although these energy devices have become safe alternatives to vascular staplers and clips, their efficacy is diminished when applied to calcified arteries. Therefore, vas­cular staplers and clips should be considered instead when a calcified mesenteric vascular pedicle is encountered.

colonic mobilization

There are several acceptable approaches to mobilizing and resecting segments of the colon for cancer, and expert sur­geons advocate various techniques. Our description here provides general technical principles and anatomic land­marks that should be applicable to all patients. There are two prevalent approaches to mobilization of the colon: medial to lateral and lateral to medial. Many surgeons find that a lateral to medial approach, performed similarly in both open and laparoscopic cases, is more straightforward. However, most of the early pioneers in laparoscopic colon surgery described a medial to lateral dissection, a technique that is not commonl y employed for standard open resec­tions. This technique advocates vascular isolation and high ligation first, followed by dissection into the retromesenteric plane to separate the mesocolon from the retroperitoneum, with lateral attachments of the colon left intact until the end of the dissection. Proponents of the medial to lateral approach point out that leaving the lateral attachments intact until the mesocolon is dissected and ligated provides upward retraction and exposure of the mesentery to facili­tate high ligation and keeps the redundancy of a laterally mobilized colon out of the way.

Regardless of the technique advocated, depending on the patient, each approach may have substantial advantages over the other. Therefore, it is wise for a surgeon to be

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versatile and familiar with anatomy and various approaches for dissection whether operating openly or laparoscopically in case of unexpected pathology or other anatomic obstacles that a patient may present.

open right colectomy

The patient is placed supine on the operating table. A ver­tical midline incision is made, mostly cephalad to the umbi­licus, and exposure of the operative field is established with a self­retaining retractor such as the Bookwalter. Thorough examination of the peritoneal cavity for metastatic disease is performed with particular focus on potential metastasis to the liver, peritoneal surfaces (carcinomatosis), and ovaries. The resectability of the tumor is determined, and if the tumor is adherent to adjacent viscera, an en bloc resection should be performed. It is uncommon for a right colon can­cer to be unresectable, and careful review of the preopera­tive staging CT scan usually avoids encountering an unresectable tumor intraoperatively as a surprise. When, on occasion, an unresectable tumor is encountered due to extensive involvement of the vena cava, head of the pan­creas, or superior mesenteric artery, a palliative resection or intestinal bypass is recommended.

The operation is commenced with retraction of the cecum anteriorly and medially, and the peritoneal attachments of

the inferolateral portions of the cecum and the terminal ileum are divided with electrocautery. With appropriate retraction on the cecum, sharp dissection is used to release the mesentery from the retroperitoneum. At this point, the right ureter can usually be seen laterally, crossing the iliac artery at its point of bifurcation [see Figure 3]. The lateral peritoneal attachment of the colon (i.e., the white line of Toldt) is sharply incised, allowing for lateral to medial mobi­lization of the right colon and mesentery. The retroperito­neal surface should deliberately be left intact and the mesentery sharply peeled off it. Dissecting into the retroper­itoneum can lead to losing the proper dissection plane and inadvertent mobilization and injury of the right kidney, ure­ter, or duodenum. The duodenum should always be identi­fied and preserved during a right colectomy as the colon mesentery is mobilized medially and dissected apart from the mesentery, pushing it back toward the retroperitoneum. This maneuver will facilitate high ligation of the colon mes­entery without risking injury to the duodenum. The hepatic flexure must also be completely released. The suspensory ligaments of the hepatic flexure should be ligated in a hemo­static fashion as large veins are often present within them, which can retract and bleed. While taking down the hepatic flexure, a decision should be made regarding whether an omentectomy will be performed. It is generally accepted

Figure 3 Anatomic relations between the colon and the retroperitoneal organs.

Right Suprarenal Gland

Inferior Vena Cava

Spleen

Left Kidney

Pancreas

Superior MesentericVein and Artery

Descending Colon

Duodenum: Ascending Part

Abdominal Aorta

Portal Vein

Right Kidney

Bile Duct

Duodenum: Superior Part

Gastroduodenal Artery

Duodenum: Descending Part

Duodenum: Inferior Part

Ascending Colon

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that partial omentectomy should be performed in the case of malignancies near or distal to the hepatic flexure. Next, the lesser sac must be entered to mobilize the proximal trans­verse colon. The most common approach to doing this is by lifting the omentum anteriorly and incising the avascular attachment of the posterior leaflet of the omentum to the anterior surface of the colon. If the omentum is planned to be resected en bloc with the transverse colon, the gastrocolic omentum itself is divided, leaving a small portion of omen­tum attached to the stomach and gastroepiploic vessels. As the hepatic flexure and proximal transverse colon are mobi­lized toward the middle colic vessels, excessive medial trac­tion must be avoided as that may lead to tearing of vessels, including the gastrocolic trunk, superior mesenteric vessels, and branches of the pancreaticoduodenal vessels, especially as they converge over the head of the pancreas, where these vessels will retract and lead to troublesome bleeding.

Once mobilization of the colon and mesentery is com­plete, the sites of proximal and distal transection of the bowel are determined. Proximally, transection of the termi­nal ileum is usually standard within 5 to 10 cm of the ileo­cecal valve. The distal site of transection is determined by whether a standard right hemicolectomy is planned versus an extended right hemicolectomy when the tumor involves or is distal to the hepatic flexure. A standard right hemico­lectomy is appropriate for tumors proximal to the hepatic flexure, removing the right branch of the middle colic artery along with the associated nodal tissue as its distal transec­tion site. When an extended right hemicolectomy is required, the dissection of the retroperitoneal plane from the mesoco­lon is extended distal to the main middle colic arterial trunk anterior to the pancreas, where it is ligated and included in the resected specimen. An extended right hemicolectomy requires considerably more effort than a standard resection, not only in isolating and ligating the middle colic pedicle at its origin but also perhaps more so in ensuring adequate mobility and perfusion of the remaining transverse colon and splenic flexure for the creation of an ileocolic anastomo­sis. Since the distal transverse colon and splenic flexure will no longer receive blood flow from the middle colic artery, its perfusion is dependent on collateral circulation via the mar­ginal artery arising from the left colic vessels. Although this collateral circulation is usually sufficient, there may be some patients, especially those with vascular disease, in whom the distal transverse colon or splenic flexure is no longer ade­quately perfused for anastomosis. If the remaining perfusion is questionable, the resection should be continued to include the remaining transverse colon and splenic flexure and an ileum to descending colon anastomosis should be planned.

Once the proximal and distal transection of bowel is per­formed along with mesenteric division and vascular pedicle ligation according to the location of the tumor, the specimen is liberated and an ileocolic anastomosis may be performed. A variety of anastomotic techniques may be performed, and these are generally categorized as stapled versus hand sewn. In a recent meta­analysis, stapled ileocolic anastomoses demonstrated a lower leak rate compared with hand sewn, although the rates of reoperation and other anastomotic complications were not significantly different.60 Therefore, the selection of anastomotic technique should ultimately be

determined by the experience and preferences of the operat­ing surgeon. The authors prefer a stapled side­to­side func­tional end­to­end anastomosis (EEA). Regardless of the chosen technique, the anastomosis should be performed on well­perfused small bowel and colon in antimesenteric areas where the staple or suture lines do not disrupt mesenteric blood flow, cause bleeding or hematoma at the anastomosis, or incorporate excessive serosal fat appendages. Furthermore, special attention must be paid to ensuring proper orienta­tion of the small bowel mesentery and preventing the small bowel from twisting proximal to the anastomosis. Tradi­tional teaching has also been to close the resulting mesen­teric defect to reduce the risk of an internal hernia and obstruction, but a recent study suggested that leaving the defect open does not lead to any significant consequences.61

laparoscopic right colectomy

The steps for a laparoscopic right colectomy [see Video 1] are very similar to those described above for open right colectomy when a lateral to medial dissection is chosen. The patient is positioned for a laparoscopic approach, as previously described, and ports are positioned after estab­lishing pneumoperitoneum with CO2 and placed in the steep Trendelenburg position with the right side elevated [see Figure 4]. The small bowel is swept out of the pelvis and to the left, and the omentum is also swept over the liver and into the epigastrium. The cecum is grasped through the left lower quadrant port, typically by the peri­cecal or periappendiceal appendages, and retracted anteri­orly and medially [see Figure 5]. The surrounding peritoneal attachments are incised with laparoscopic scissors with a cautery attachment through the right suprapubic port, and the lateral to medial mobilization is completed as described for open right colectomy.

When a medial to lateral approach is preferred, the cecum is grasped and retracted anteriorly and laterally to place the ileocolic vascular pedicle on stretch and the peri­toneal surface is incised along the posterior groove of the pedicle to create a retromesenteric window [see Figure 6]. The avascular plane between the mesentery and the retro­peritoneum is identified and bluntly dissected all the way to the abdominal wall laterally and the transverse colon

Video 1 Laparoscopic right colectomy.

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Figure 4 Port positioning for laparoscopic colectomy. (a) Right colectomy port placement. (b) Left colectomy port placement.

a b

Figure 5 Laparoscopic colectomy: right hemicolectomy. Right colon mobilization.

Figure 6 Laparoscopic colectomy: right hemicolectomy. Right colon mesenteric dissection.

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superiorly. The duodenum must be identified and dis­sected off the mesentery during dissection prior to ligating the ileocolic pedicle at its origin with a vessel­sealing device such as the LigaSure or EnSeal. The remainder of the ascending colon mesentery is divided up to and including the right branch of the middle colic artery. This leaves only a thin layer of lateral attachments of the ascending colon and terminal ileum as well as the hepatic flexure holding the right colon. These attachments are then easily incised to release the terminal ileum such that it could easily be exteriorized through an umbilical extraction incision.

Whether a lateral to medial or medial to lateral dissection is undertaken, as the hepatic flexure is approached, the patient should be repositioned in the reverse Trendelenburg position, still with the right side up, allowing the weight of the transverse colon to provide caudad retraction on the hepatic flexure. The attachments of the hepatic flexure can then be dissected posteriorly off the retroperitoneum and divided with a vessel­sealing device. The omentum and entrance into the lesser sac for transverse colon mobilization can be approached similarly to the description for open right hemicolectomy. Once the transverse colonic dissection is past the midline as referenced by the falciform ligament, the colon is replaced in its anatomic position. If a medial to lat­eral dissection was performed, the colon is at this point ready to be exteriorized as the mesentery is already divided. For a lateral to medial dissection, a high ligation of the vas­cular pedicles and adjacent mesentery must still be per­formed either intracorporeally or extracorporeally through the abdominal incision.

On complete laparoscopic mobilization of the bowel from terminal ileum to transverse colon and division of the vas­cular pedicle(s) and mesenteric attachments, the cecum is grasped with a locking grasper through the right suprapubic port. The terminal ileum and distal point of colonic transec­tion should easily reach the anterior abdominal wall prior to releasing pneumoperitoneum to ensure adequate mobility for specimen extraction and extracorporeal anastomosis. The umbilical camera trocar is then enlarged to 3 to 5 cm length depending on the size of the patient and anticipated size of the specimen. A wound protector is placed to avoid potential malignant contamination of the wound as well as facilitate delivery of the specimen through a small incision. The specimen is exteriorized from terminal ileum to mid–transverse colon, transected with staplers to liberate the specimen, and prepared for construction of an extracorpo­real ileocolic anastomosis using standard open surgical instruments and technique. Specific attention is paid to the orientation of the bowel to ensure that there are no twists in the small bowel leading into the anastomosis. Once the anas­tomosis is performed, the bowel is replaced in the abdomen and the incisions are closed. Laparoscopic intracorporeal ileocolic anastomosis can be performed but has not been adopted by most expert laparoscopic colon surgeons because the decrease in extraction incision length by 1 cm with intra­corporeal anastomosis is of no meaningful clinical value.62

open left colectomy

The patient is placed in low lithotomy on the operating table. A vertical midline incision is made, mostly caudad to the umbilicus to just above the pubis, and exposure of the

operative field is established with a self­retaining retractor such as the Bookwalter. Thorough examination of the peri­toneal cavity for metastatic disease is performed and resect­ability assessed as for a right colectomy. We usually begin by identifying the sigmoid colon, retracting it medially, and exposing the frequently encountered adhesions between the sigmoid colon, its mesentery, and the lateral abdominal wall. A segment of the sigmoid can often be found folded into the pelvis over the peritoneal reflection or adhesed to adnexal structures in women. A combination of gentle blunt dissection with careful cautery or sharp transection of tissue is used to free these attachments and straighten the sigmoid colon to achieve clear visualization of the white line of Toldt. However, blunt dissection of attachments and planes around the tumor itself should be avoided and direct manipulation of the tumor itself minimized.

The white line of Toldt is incised laterally and the colon retracted medially to free the sigmoid mesentery from the retroperitoneum. Care should be taken to stay in the avascu­lar plane between the mesentery and retroperitoneal surface. Preserving the integrity of the mesocolic and retroperitoneal surfaces will help ensure clearance of the mesenteric lymph node–bearing tissue for oncologic purposes as well as main­taining a bloodless field in the retroperitoneum, which helps ease identification of the left ureter as it crosses the iliac arteries and descends into the pelvis. When inflammation or a reoperative field that may distort this anatomic plane is anticipated preoperatively, a ureteral stent should be con­sidered as discussed earlier.

The points of transection in a left colectomy are not as standard as a right colon resection. Depending on the loca­tion of the tumor, proximal margins are defined as the dis­tal transverse colon or somewhere along the descending colon according to the principle of having a minimum of a 5 cm clear margin on either side of the tumor. The distal margin has been described as the rectosigmoid junction or the sigmoid colon, again depending on the location of the tumor along the significant distance between the rectosig­moid junction and splenic flexure. The operation that is undertaken should respect basic oncologic principles as previously discussed, with resection of one blood vessel proximal and one distal to the tumor. If nodal disease is apparent outside the scope of standard mesenteric resec­tion, then a broader resection, including retroperitoneum and adherent peritoneal structures, should be undertaken for locoregional control. Another important determinant of the points of transection in a left colectomy is blood supply. A tension­free anastomosis with good blood supply is crit­ical to minimize the risk of an anastomotic leak. When the tumor is in the sigmoid colon, the distal margin will be the rectosigmoid junction and the IMA should be divided near its origin with the mesentery in its distribution incorpo­rated in the specimen. If a resection is planned that incor­porates the sigmoid colon as the distal portion of the anastomosis, as it would be for a descending colon or splenic flexure tumor, then it is important to carefully pre­serve the sigmoid arteries arising from the IMA to maintain perfusion of the distal side of the anastomosis. The portion of colon that comprises the proximal portion of the anasto­mosis, usually the transverse colon, should be mobilized

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sufficiently to allow a tension­free anastomosis. This often requires proximal division of the IMV and the complete mobilization of the splenic flexure.

Once the lateral to medial mobilization of the colon is completed according to the extent of resection required by the tumor location, the points of transection are selected and the colon is divided proximally and distally with a gastroin­testinal stapler. The associated mesentery surface is scored with cautery and then serially clamped and ligated with absorbable sutures or with an energy delivery device accord­ing to the oncologic and blood supply considerations described above. This liberates the specimen, and an anasto­mosis is then performed. A stapled side­to­side colocolic anastomosis is generally discouraged in the left colon as these anastomoses may create a dilated reservoir. A hand­sewn EEA is preferred in these circumstances. Colorectal anastomoses can be hand­sewn or stapled using an EEA sta­pling device according to the preference and experience of the surgeon. We generally perform these anastomoses with the EEA stapler.

When the sigmoid colon is resected as part of the speci­men and a colorectal anastomosis is planned, an EEA sta­pler can be used to easily and reliably perform an EEA into the upper rectum as long as the surgeon adheres to a few technical principles. The largest stapler that will fit into the rectum and colon is selected; placing sizers in the rectum and colon for a test run prior to committing to a stapler size is recommended. Avoid using EEA staplers smaller than 28 to 29 mm for a colorectal anastomosis to minimize the risk of stricture. If a 28 to 29 mm or larger stapler is not able to fit into the rectal stump, it usually indicates that the stump is composed of distal sigmoid colon, which usually has a narrower luminal caliber than the true rectum and may be associated with diverticular disease. When this occurs, it is advised that further resec­tion is performed toward the rectum rather than forceful

placement of the stapler into the stump or using a smaller caliber EEA stapler.

Once the surgeon is confident that the EEA stapler will reach the top of the rectal stump, the EEA anvil is secured into the colon with a monofilament purse­string stitch around the cut edge of the colon tied in place. This must be done precisely to incorporate full thickness of the colon in its entire circumference to avoid any gaps in the circular sta­ple line on the proximal side of the anastomosis. The stapler is placed through the anus into the rectum and guided such that the spike of the stapler can be protracted adjacent to the transverse staple line on the rectal stump rather than through it, which runs the risk of separating the staple line. Another technical pitfall to avoid is deploying the spike of the stapler too far from the transverse staple line, which would align the circular staples line adjacent to the transverse staple line, creating an ischemic ridge of tissue at the anastomosis, which renders the anastomosis at risk for dehiscence [see Figure 7]. After engaging the anvil to the spike of the stapler, the stapler is fired and removed from the rectum with gentle twisting motions. The tissue donuts are removed from the stapler and examined for completeness. The pelvis is then filled with irrigation fluid, and a rigid proctoscope or flexible sigmoidoscope is inserted into the rectum. With the colon clamped proximal to the anastomosis, the rectum is insufflated with air to determine if there is any air leak from the anastomosis. An advantage of using a flexible sigmoid­oscope for this step instead of the traditional rigid procto­scope is that the surgeon and any other assistant involved can clearly visualize the anastomosis on a high­resolution monitor and assess its integrity and hemostasis. In cases where an air leak is appreciated, the anastomosis should either be reinforced with sutures and reevaluated or com­pletely resected and reconstructed. If the surgeon is not fully satisfied with the repair of an air leak, a temporary diverting ileostomy is the safest course of action.

Figure 7 Configuration of an end-to-end stapled colorectal anastomosis. (a) Double-staple colorectal anastomosis (ideal). (b) Double-staple colorectal anastomosis (avoid).EEA = end-to-end anastomosis.

a b

Transverse staple line Transverse staple lineEEA staple line

EEA staple line

Rectal WallRectal Wall

Ischemic Ridge

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laparoscopic left colectomy

The laparoscopic approach to sigmoid and descending colon mobilization is very similar to the open approach when the lateral to medial dissection is employed. The patient is positioned in low lithotomy for a laparoscopic approach, as previously described, and ports are positioned after establishing pneumoperitoneum with CO2 and placed in the steep Trendelenburg position with the left side rotated anteriorly [see Figure 4]. The small bowel is swept out of the pelvis and to the right, and the omentum is also swept into the right upper quadrant. The sigmoid is grasped and retracted medially, and the lateral adhesions are taken down with cautery and bluntly as necessary [see Figure 8]. Medial traction placed on the peritonealized surfaces provides visu­alization of the avascular plane between the mesentery and retroperitoneum to facilitate gentle and bloodless dissection. This dissection proceeds proximally to the splenic flexure and distally to the pelvic brim, where the left ureter is iden­tified. As in right colon mobilization, the plane between the mesentery of the colon and retroperitoneum is often more medial than expected. The unsuspecting surgeon can easily dissect too lateral, close to the lateral abdominal wall, pene­trate the retroperitoneum, and lead to dissection behind the kidney. Once the dissection reaches the upper extent of the descending colon, the patient is shifted into the reverse Trendelenburg position, still with the left side rotated ante­riorly, and splenic flexure mobilization proceeds. Once the

left colon is completely mobilized, proximal ligation of the vascular pedicles and mesentery is performed according to the tumor location and patient anatomy.

When a medial to lateral approach is performed, the left colon mesentery is visualized medially down to its origin as the lateral attachments hold up the colon and mesentery. The IMV and IMA vascular pedicles are identified with upward traction on the mesentery. A reliable anatomic landmark to identifying the IMV is the ligament of Treitz. The peritoneal surfaces on the caudal side of the IMV and IMA are incised to find the avascular plane between the mesentery and the retroperitoneum. This plane is bluntly dissected all the way to the abdominal wall laterally and the transverse colon/splenic flexure superiorly. When in the proper plane, this dissection is bloodless. Bleeding indicates that the surgeon has likely penetrated either the retroperi­toneum or the colon mesentery and should modify the approach to find the correct plane. The left ureter must be identified during dissection prior to any vascular ligation. The IMA and/or IMV pedicles are ligated with a vessel sealing device such as the LigaSure or EnSeal according to the tumor location and vascular supply considerations. This leaves only a thin layer of lateral attachments of the sig­moid and descending colon as well as the splenic flexure holding the left colon. These attachments are then easily incised to release the entire left colon, and the patient is similarly repositioned to the reverse Trendelenburg posi­tion for splenic flexure mobilization.

Whether a lateral to medial or medial to lateral dissection is undertaken, for resections that include the sigmoid colon and/or upper rectum, dissection should proceed distally into the pelvis to mobilize the upper rectum. This can be performed laparoscopically or using open techniques directly through a small lower midline or Pfannensteil inci­sion that is planned for specimen extraction. The mesentery and other fatty tissue are then cleared to the bowel wall of the rectum/rectosigmoid junction, allowing for division of the bowel in a region that has minimal adherent fat or mes­entery. If this mesenteric clearing is not performed, espe­cially in obese patients, fitting a stapling device across the bowel will be problematic. An endoscopic articulating sta­pling device with a 3.5 mm staple height (4.1 mm when the bowel is thicker as with the rectum) is placed through a right lower quadrant port and fired across this cleared area for distal transection of the bowel. The number of staple loads fired to transect the bowel should be minimized as multiple crossing staple lines could place the quality of the anastomosis at risk. Alternatively, the distal transection could be performed directly through the extraction or hand­assisted port incision with a single firing of a trans­verse stapling device. The distal margin of the specimen is then manually exteriorized through the planned extraction incision after placement of a wound protector to deliver the tumor, intact mesentery, and whatever proximal level of colon (descending or transverse) transection is required according to the tumor location. The proximal margin of bowe l is divided extracorporeally, but the surgeon must be confident that there is enough mobilized and well­perfused proximal bowel to return into the peritoneal cavity for a tension­free anastomosis. Typically, if the proximal bowel can be stretched to the symphysis pubis through a lower

Figure 8 Laparoscopic colectomy: left hemicolectomy and sigmoid resection. Sigmoid mesentery and pelvic dissection.

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midline or Pfannensteil extraction incision, there will be adequate length for a pelvic anastomosis. The colorectal anastomosis is performed with an EEA stapling technique as described earlier for open left colectomy. If the extraction incision required to remove the specimen accommodates visualization of the rectal stump, the EEA stapling can be performed under direct vision. Otherwise, the proximal colon is returned to the peritoneal cavity with the anvil secured in it, the extraction incision is either closed or sealed with the wound protector, and pneumoperitoneum is reestablished. The EEA stapling is then performed intra­corporeally, adhering to the same technical and quality con­trol principles as previously described. If the colectomy is for a proximal descending colon or splenic flexure tumor, then a colocolonic anastomosis between the transverse colon and sigmoid colon is required. This usually cannot be performed with an EEA stapler because the transanally placed stapler cannot reach the sigmoid stump. In these sit­uations, the sites of proximal and distal transection should be mobilized sufficiently to allow an extracorporeal hand­sewn anastomosis.

splenic flexure mobilization

Splenic flexure mobilization is a critical and often under­appreciated technical element of left­sided colectomy. It allows the surgeon to release the transverse and descending colon from the left upper quadrant, facilitating reach of the bowel for a well­perfused and tension­free anastomosis. Depending on the patient’s anatomy and body habitus, the splenic flexure mobilization can often be the most challeng­ing task for the surgeon to perform during a left colectomy or proctectomy. The difficulty is primarily due to issues regarding exposure and the risk of injuring the splenic cap­sule, vessels within the splenocolic ligament that can retract and bleed, or injury to the colon wall or mesentery. Stretch­ing the descending colon down toward the pelvis or resect­ing a shorter segment of colon to leave enough, but poorly perfused, length of colon for anastomosis may result in an anastomosis that is under tension and/or ischemic, which places the patient at higher risk for anastomotic leak that could have been avoided with splenic flexure mobilization.

When performed during an open operation, the midline incision used generally needs to extend above the umbilicus, although there are occasional patients in whom the splenic flexure is unusually mobile or low where the mobilization can still be performed through a primarily infraumbilical incision. In exposing the splenic flexure, a self­retaining retractor is used, elevating the ring or fixed bar so that retractors pull the abdominal wall anteriorly as well as toward the left upper quadrant. It is usually helpful to reposition the center of the retractor ring cephalad and toward the left upper quadrant after completing the sig­moid and pelvic dissection. It is also helpful for the assis­tant surgeon to stand between the patient’s legs for better visualization, especially with high and difficult flexures. Complete splenic flexure mobilization usually requires a bidirectional approach: clockwise from transverse colon to splenic flexure or counterclockwise from descending colon to splenic flexure [see Figure 9].

The counterclockwise approach requires that the surgeon lift the plane of the dissected descending colon, exposing the

attachments of the splenic flexure to the retroperitoneum and proceeding toward the transverse colon. The proper plane here is again closer to the colon, and not recognizing it will lead to the deeper and more lateral retroperitoneal plane misleading the surgeon posterior to the left kidney. With a hand in the plane posterior to the colon providing gentle traction toward the right lower quadrant, the tissue attaching the apex of the flexure to the spleen is exposed and divided. This requires suture ligation or division using an energy delivery device; otherwise, vessels within this tissue can retract toward the spleen and then bleed. Care should be taken with this maneuver to avoid excessive traction on the splenocolic ligament, which can result in avulsion of the splenic capsule and troublesome bleeding that, on occasion, requires splenectomy to control. To minimize this risk, the surgeon should gently expose these attachments with a fin­ger or right angle clamp underneath the attachments and allow them to be divided in situ, closer to the bowel wall, instead of attempting to retract them anteriorly. There is no need to dissect near the spleen itself; the colon needs to be mobilized, not the spleen. As the apex of the flexure is released, dissection proceeds medially. Attention must be paid during this dissection to avoid injuring the pancreas and duodenum laying directly posterior and medial to the splenic flexure. The lesser sac can be entered through the gastrocolic omentum, leaving the omentum on the trans­verse colon, or the omentum can be manipulated superiorly and the lesser sac entered from beneath the omentum along the border of the transverse colon, leaving the omentum attached to the stomach. The counterclockwise dissection often reaches a point where the exposure becomes subopti­mal or the planes of dissection become less clear; this will be the point where dissection should be converted to a clock­wise direction from the transverse colon to splenic flexure. As the lesser sac is opened and omental attachments are released, the remaining attachments of the splenic flexure become obvious and are released. The medial extent of transverse colonic dissection depends on the distance it needs to be mobilized to reach the site of anastomosis with­out tension.

laparoscopic splenic flexure mobilization

Laparoscopic mobilization of the splenic flexure is similar to that described above but often more challenging than the open approach, particularly in obese patients with high flex­ures. Placing an additional trocar in the right upper quadrant is very helpful, allowing the surgeon to retract the omentum and stomach anteriorly/cephalad, thereby giving better exposure to the lesser sac. The hand­assisted laparoscopic approach is a valuable tool to overcome these challenges and provide the traction needed instead of laparoscopic graspers with patients anticipated to have a difficult flexure. Placing the patient in the reverse Trendelenburg position with the left side rotated anteriorly is key to establishing the needed exposure for the counterclockwise and clockwise dissections described.

total abdominal colectomy with ileorectal anastomosis

A total abdominal colectomy may be indicated in cases where a patient is diagnosed with HNPCC, attenuated FAP,

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synchronous cancers in the right and left colon, or an acutely obstructing left colon cancer with unknown status of the proximal colon. The technical aspect of the total colectomy is a conglomeration of the descriptions above for the seg­mental colectomies. The terminal ileum must be mobilized from its lateral attachments to reach the rectum without tension and without any twisting of the mesentery to avoid ischemia and obstruction. Given the usual size discrepancy between the ileum and rectum, attention must be given to proper sizing of the EEA circular stapler. The anvil of the EEA stapler should be secured into the ileum such that it is not a tight fit and is not incorporating the mesentery of the ileum into the anastomosis. According to the preference of the surgeon, the antimesenteric side of the ileum can be anastomosed to the end of the rectum or an EEA can be performed.

postoperative care

Care after colectomy is primarily a function of three main goals: (1) adequate pain control, (2) awaiting the return of bowel function, and (3) vigilance for complications of surgery.

Patient­controlled analgesia is widely accepted as effective management of postoperative pain, although many proto­cols call for the use of epidural catheters when appropriate. The routine use of nasogastric tubes after colectomy is no longer considered acceptable. Similarly, a course of antibiot­ics longer than 24 hours postoperatively is also not recom­mended. Early enteral feeding has been proven to be safe. Once patients are tolerating a low­residue diet, which decreases the local inflammatory response at the anastomo­sis, and passing flatus or stool, they can be discharged home, with follow­up after 2 weeks.63

Fast­track protocols have been developed and studied in multiple institutions in the hope of creating uniformity of care and decreasing postoperative stay. Common character­istics of these protocols are fluid minimization both in the operating room and postoperatively, epidural use, and early enteral feeding.64 Further components of fast tracking include Foley catheter removal on postoperative day 1, no oral bowel preparation, scheduled nonnarcotic analgesia (e.g., intravenous ketorolac or oral acetaminophen), and early ambulation.29,64 These strategies have commonly been shown

Figure 9 Dissection of the splenic flexure can be approached in one of two directions: clockwise or counterclockwise. Usually, both directions need to be undertaken to perform a complete mobilization.

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Table 1 Complications of ColectomyComplications common to any abdominal surgery requiring general anesthesia DVT and PE Myocardial infarction Stroke Pneumonia Wound infection Urinary tract infection

Complications specific to colectomy Injury to the spleen mandating splenectomy Enterocutaneous fistulas Injuries to the genitourinary structures Extremity nerve injury secondary to positioning Small bowel obstruction Anastomotic leak

DVT = deep vein thrombosis; PE = pulmonary embolism.

to decrease length of stay by 4 to 6 days without increasing readmissions and potentially decrease complications by nearly 50% in open colorectal surgery.65,66 The efficacy of fast­track protocols has been demonstrated in laparoscopic surgery as well, with fast­track patients having shorter times to enteral feeding (decreased by 1 day) and first bowel movement (decreased by 1 day), shorter lengths of stay (3 versus 4 to 5 days), and fewer complications (15 to 29% versus 25 to 56%).29,64

complications

Complications are best minimized through careful plan­ning and adherence to the principles of safe surgical tech­nique. Despite this, complications will occur, even in the most skilled and experienced hands.67 The ability to recog­nize and successfully manage complications is often what distinguishes the most capable surgeons. Colectomy is associated with a distinct set of complications, in addition to those common to any abdominal surgery requiring gen­eral anesthesia [see Table 1]. The rates of these complica­tions, although never completely eliminated, may be minimized by following national guidelines for prevention and treatment.

A survey of all complications specific to colectomy requires a dedicated review. One complication, however, requires special attention: the dreaded complication of anastomotic leak. Clinically significant anastomotic leaks probably occur more frequently in daily practice than the surgical literature admits, which is often biased to report our successes rather than our failures. If we focus on the reported leak rates from the CLASICC, COLOR, and COST trials, which are the results of a highly selected group of surgeons, anastomotic leaks occur in 2 to 6% depending on where in the colon the anastomosis is made.47–49 In general, the more distal the anastomosis, the higher the rate of leak­age. This rate should be distinguished from distal colorectal anastomoses after proctectomy, where leak rates are signifi­cantly higher, in the range of 10 to 20%, especially in the setting of neoadjuvant radiation therapy.

The goals in management of an anastomotic leak are to effectively treat the leak and control sepsis. The treatment approach is individualized to the location and severity of

the leak and the condition and comorbidities of the patient. Management of the stable patient without signs of peritoni­tis usually begins with imaging to identify and localize the process. A CT scan of the abdomen and pelvis with triple contrast (oral, intravenous, and rectal) is the imaging modality of choice. Large collections are often amenable to percutaneous drainage. In the era of modern CT scanning and interventional radiology, the routine practice of repeat laparotomy, abdominal washouts, and large sump drains is usually not necessary and can be reserved for patients who fail to respond to, deteriorate following, or are not candi­dates for percutaneous drainage. On the other hand, man­agement of the patient with progressive generalized peritonitis requires resuscitation, broad­spectrum antibiotics, and urgent laparotomy. If the findings at exploration show ischemia and necrosis of greater than one third of the anas­tomosis, the anastomosis should be resected with creation of an end stoma. If the findings identify a smaller leak with healthy bowel, the anastomosis can usually be salvaged with suture repair, washout with drainage, and proximal diversion with a loop ileostomy.

Another common anastomotic problem is bleeding, which varies in severity, but most cases are mild and self­limited. Significant anastomotic bleeding occurs approximately 1% of the time, which can usually be suc­cessfully managed with endoscopic epinephrine injection or clip application at the bleeding site. If this fails and the anastomosis is proximal, selective endovascular emboliza­tion may be an option. When bleeding is massive and results in hemodynamic instability, the patient is best returned to the operating room for surgical intervention. Anastomotic strictures can occur in up to 10%, which may be related to anastomotic compromise or subclinical leak secondary to ischemia, tension, or inflammation. Although assessment of blood flow, tension, and bowel appearance as discussed in the technical descriptions earlier makes anas­tomotic complications less likely, these will still occur. Finally, mortality may occur in 1% or more of colectomy cases, although this risk depends heavily on patient preop­erative risk factors, emergent indications for surgery, and the complexity of the surgery itself.68

One notable theme that has emerged in the recent litera­ture investigating the quality of surgical care is the concept of “rescue.” In examining hospitals with widely varying death rates, it has been demonstrated that the underlying rate of serious complications is similar across these hospi­tals.69 What is markedly different is the ability of hospitals to respond quickly and adequately to prevent worsened morbidity or mortality from a complication of surgery. This ability to “rescue” patients is an emergent property of various aspects of each hospital, including nursing care, ancillary staff, and culture. It is incumbent on each surgeon who performs colectomies to be part of a system that is focused not only on preventing complications with metic­ulous surgical technique but also on recognizing them and treating them quickly and appropriately.

Financial Disclosures: Kevork Kazanjian, MD, FACS, and David A. Etzioni, MD, MSHS, FACS, have no relevant financial relationships to disclose.

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References

1. American Cancer Society. Cancer facts & figures. 2013. Atlanta (GA): American Cancer Society.

2. Kohler BA, Ward E, McCarthy BJ, et al. Annual report to the nation on the status of cancer, 1975–2007, featuring tumors of the brain and other nervous system. J Natl Cancer Inst 2011;103:714–36.

3. Edwards BK, Ward E, Kohler BA, et al. Annual report to the nation on the status of cancer, 1975–2006, featuring colorec­tal cancer trends and impact of interventions (risk factors, screening, and treatment) to reduce future rates. Cancer 2010;116:544–73.

4. Etzioni DA, Beart RW Jr, Madoff RD, Ault GT. Impact of the aging population on the demand for colorectal proce­dures. Dis Colon Rectum 2009;52:583–90; discussion 590–1.

5. Bal DG. Cancer in African Americans. CA Cancer J Clin 1992;42:5–6.

6. Arriaga AF, Lancaster RT, Berry WR, et al. The Better Colectomy Project: association of evidence­based best­ practice adherence rates to outcomes in colorectal surgery. Ann Surg 2009;250:507–13.

7. Cohen ME, Bilimoria KY, Ko CY, Hall BL. Development of an American College of Surgeons National Surgery Quality Improvement Program: morbidity and mortality risk calcu­lator for colorectal surgery. J Am Coll Surg 2009;208: 1009–16.

8. Poultsides GA, Servais EL, Saltz LB, et al. Outcome of pri­mary tumor in patients with synchronous stage IV colorectal cancer receiving combination chemotherapy without surgery as initial treatment. J Clin Oncol 2009; 27:3379–84.

9. Bertelson NL, Kalkbrenner KA, Merchea A, et al. Colec­tomy for endoscopically unresectable polyps: how often is it cancer? Dis Colon Rectum 2012;55:1111–6.

10. Nusko G, Mansmann U, Altendorf­Hofmann A, et al. Risk of invasive carcinoma in colorectal adenomas assessed by size and site. Int J Colorectal Dis 1997;12: 267–71.

11. Alder AC, Hamilton EC, Anthony T, Sarosi GA Jr. Cancer risk in endoscopically unresectable colon polyps. Am J Surg 2006;192:644–8.

12. McDonald JM, Moonka R, Bell RH Jr. Pathologic risk factors of occult malignancy in endoscopically unresectable colonic adenomas. Am J Surg 1999;177:384–7.

13. Kudo S. Endoscopic mucosal resection of flat and depressed types of early colorectal cancer. Endoscopy 1993;25: 455–61.

14. Nivatvongs S. Surgical management of malignant colorectal polyps. Surg Clin North Am 2002;82:959–66.

15. Bat L, Neumann G, Shemesh E. The association of synchro­nous neoplasms with occluding colorectal cancer. Dis Colon Rectum 1985;28:149–51.

16. Small AJ, Coelho­Prabhu N, Baron TH. Endoscopic place­ment of self­expandable metal stents for malignant colonic obstruction: long­term outcomes and complication factors. Gastrointest Endosc 2010;71:560–72.

17. Sebastian S, Johnston S, Geoghegan T, et al. Pooled analysis of the efficacy and safety of self­expanding metal stenting

in malignant colorectal obstruction. Am J Gastroenterol 2004;99:2051–7.

18. Brehant O, Fuks D, Bartoli E, et al. Elective (planned) colec­tomy in patients with colorectal obstruction after placement of a self­expanding metallic stent as a bridge to surgery: the results of a prospective study. Colorectal Dis 2009;11: 178–83.

19. National Comprehensive Cancer Network (NCCN). Clinical practice guidelines in oncology: colon cancer version 3. 2013. www.nccn.org/professionals/physician_gls/f_guidelines.asp (accessed June 29, 2015).

20. Liu SK, Church JM, Lavery IC, Fazio VW. Operation in patients with incurable colon cancer—is it worthwhile? Dis Colon Rectum 1997;40:11–4.

21. Croner RS, Merkel S, Papadopoulos T, et al. Multivisceral resection for colon carcinoma. Dis Colon Rectum 2009; 52:1381–6.

22. Mayo SC, Pulitano C, Marques H, et al. Surgical manage­ment of patients with synchronous colorectal liver metasta­sis: a multicenter international analysis. J Am Coll Surg 2013;216:707–16; discussion 716–8.

23. Selzner M, Hany TF, Wildbrett P, et al. Does the novel PET/CT imaging modality impact on the treatment of patients with metastatic colorectal cancer of the liver? Ann Surg 2004;240:1027–34; discussion 1035–6.

24. Schrader K, Offit K, Stadler ZK. Genetic testing in gastroin­testinal cancers: a case­based approach. Oncology 2012; 26:433–46.

25. Vasen HF, Blanco I, Aktan­Collan K, et al. Revised guide­lines for the clinical management of Lynch syndrome (HNPCC): recommendations by a group of European experts. Gut 2013;62:812–23.

26. Moreira L, Balaguer F, Lindor N, EPICOLON Consortium. Identification of Lynch syndrome among patients with colorectal cancer. JAMA 2012;308:1555–65.

27. Slim K, Vicaut E, Launay­Savary MV, et al. Updated sys­tematic review and meta­analysis of randomized clinical trials on the role of mechanical bowel preparation before colorectal surgery. Ann Surg 2009;249:203–9.

28. Güenaga KF, Matos D, Wille­Jørgensen P. Mechanical bowel preparation for elective colorectal surgery. Cochrane Data­base Syst Rev 2011;(9):CD001544. DOI: 10.1002/14651858.CD001544.pub4.

29. Larson DW, Batdorf NJ, Touzios JG, et al. A fast­track recovery protocol improves outcomes in elective laparo­scopic colectomy for diverticulitis. J Am Coll Surg 2010; 211:485–9.

30. Hendren S, Morris AM, Zhang W, Dimick J. Early discharge and hospital readmission after colectomy for cancer. Dis Colon Rectum 2011;54:1362–7.

31. Millan M, Tegido M, Biondo S, Garcia­Granero E. Preoper­ative stoma siting and education by stoma therapists of colorectal cancer patients: a descriptive study in twelve Spanish colorectal surgical units. Colorectal Dis 2010;12 (7 Online):e88–92. DOI: 10.1111/j.1463­1318.2009.01942.x.

32. Alizadeh K, Hyman N. Venous thromboembolism pro­phylaxis in colorectal surgery. Surg Technol Int 2005; 14:165–70.

33. Geerts WH, Bergqvist D, Pineo GF, et al. Prevention of venous thromboembolism: American College of Chest Physicians Evidence­Based Clinical Practice Guidelines

Scientific American Surgery

08/15

gastro operations for colon cancer — 17

(8th Edition). Chest 2008;133(6 Suppl):381S–453S. DOI: 10.1378/chest.08­0656.

34. Leonardi MJ, McGory ML, Ko CY. A systematic review of deep venous thrombosis prophylaxis in cancer patients: implications for improving quality. Ann Surg Oncol 2007;14:929–36.

35. Nelson RL, Glenny AM, Song F. Antimicrobial prophylaxis for colorectal surgery. Cochrane Database Syst Rev 2009; (1):CD001181.

36. Bothwell WN, Bleicher RJ, Dent TL. Prophylactic ureteral catheterization in colon surgery. A five­year review. Dis Colon Rectum 1994;37:330–4.

37. Palaniappa NC, Telem DA, Ranasinghe NE, Divino CM. Incidence of iatrogenic ureteral injury after laparoscopic colectomy. Arch Surg 2012;147:267–71.

38. Redan JA, McCarus SD. Protect the ureters. JSLS 2009;13: 139–41.

39. Sticca RP, Alberts SR, Mahoney MR, et al. Current use and surgical efficacy of laparoscopic colectomy in colon cancer. J Am Coll Surg 2013;217:56–62; discussion 62–3.

40. Alnasser M, Schneider EB, Gearhart SL, et al. National dis­parities in laparoscopic colorectal procedures for colon cancer. Surg Endosc 2014;28:49–57. DOI: 10.1007/s00464­013­3160­8. [Epub 2013 Sep 4]

41. A comparison of laparoscopically assisted and open colec­tomy for colon cancer. N Engl J Med 2004;350:2050–9.

42. Klarenbeek BR, Veenhof AA, Bergamaschi R, et al. Laparo­scopic sigmoid resection for diverticulitis decreases major morbidity rates: a randomized control trial: short­term results of the Sigma Trial. Ann Surg 2009;249:39–44.

43. Bilimoria KY, Bentrem DJ, Merkow RP, et al. Laparoscopic­ assisted vs. open colectomy for cancer: comparison of short­term outcomes from 121 hospitals. J Gastrointest Surg 2008;12:2001–9.

44. Delaney CP, Marcello PW, Sonoda T, et al. Gastrointestinal recovery after laparoscopic colectomy: results of a pro­spective, observational, multicenter study. Surg Endosc 2010;24:653–61.

45. Marcello PW, Milsom JW, Wong SK, et al. Laparoscopic total colectomy for acute colitis: a case­control study. Dis Colon Rectum 2001;44:1441–5.

46. Marcello PW, Milsom JW, Wong SK, et al. Laparoscopic restorative proctocolectomy: case­matched comparative study with open restorative proctocolectomy. Dis Colon Rectum 2000;43:604–8.

47. Fleshman J, Sargent DJ, Green E, et al. Laparoscopic colec­tomy for cancer is not inferior to open surgery based on 5­year data from the COST Study Group trial. Ann Surg 2007;246:655–62; discussion 662–4.

48. Marshall CL, Chen GJ, Robinson CN, et al. Establishment of a minimally invasive surgery program leads to decreased inpatient cost of care in veterans with colon cancer. Am J Surg 2010;200:632–5.

49. Colon Cancer Laparoscopic or Open Resection Study Group, Buunen M, Veldkamp R, Hop WC, et al. Survival after laparoscopic surgery versus open surgery for colon cancer: long­term outcome of a randomised clinical trial. Lancet Oncol 2009;10:44–52.

50. Green BL, Marshall HC, Collinson F, et al. Long­term follow­up of the Medical Research Council CLASICC

trial of conventional versus laparoscopically assisted resection in colorectal cancer. Br J Surg 2013;100: 75–82.

51. Sjo OH, Merok MA, Svindland A, Nesbakken A. Prognos­tic impact of lymph node harvest and lymph node ratio in patients with colon cancer. Dis Colon Rectum 2012;55:307–15.

52. Berger AC, Sigurdson ER, LeVoyer T, et al. Colon cancer survival is associated with decreasing ratio of meta­static to examined lymph nodes. J Clin Oncol 2005;23: 8706–12.

53. Johnson PM, Porter GA, Ricciardi R, Baxter NN. Increasing negative lymph node count is independently associated with improved long­term survival in stage IIIB and IIIC colon cancer. J Clin Oncol 2006;24:3570–5.

54. Chang GJ, Rodriguez­Bigas MA, Skibber JM, Moyer VA. Lymph node evaluation and survival after curative resec­tion of colon cancer: systematic review. J Natl Cancer Inst 2007;99:433–41.

55. Mathis KL, Green EM, Sargent DJ, et al. Surgical quality surrogates do not predict colon cancer survival in the set­ting of technical credentialing: a report from the prospec­tive COST trial. Ann Surg 2013;257:102–7.

56. Marcello PW, Fleshman JW, Milsom JW, et al. Hand­ assisted laparoscopic vs. laparoscopic colorectal surgery: a multicenter, prospective, randomized trial. Dis Colon Rectum 2008;51:818–26; discussion 826–8.

57. Newcomb WL, Hope WW, Schmelzer TM, et al. Compari­son of blood vessel sealing among new electrosurgical and ultrasonic devices. Surg Endosc 2009;23:90–6.

58. Harold KL, Pollinger H, Matthews BD, et al. Comparison of ultrasonic energy, bipolar thermal energy, and vascular clips for the hemostasis of small­, medium­, and large­sized arteries. Surg Endosc 2003;17:1228–30.

59. Campagnacci R, de Sanctis A, Baldarelli M, et al. Electro­thermal bipolar vessel sealing device vs. ultrasonic coagu­lating shears in laparoscopic colectomies: a comparative study. Surg Endosc 2007;21:1526–31.

60. Choy PY, Bissett IP, Docherty JG, et al. Stapled versus handsewn methods for ileocolic anastomoses. Cochrane Database Syst Rev 2007;(3):CD004320.

61. Cabot JC, Lee SA, Yoo J, et al. Long­term consequences of not closing the mesenteric defect after laparoscopic right colectomy. Dis Colon Rectum 2010;53:289–92.

62. Hellan M, Anderson C, Pigazzi A. Extracorporeal versus intracorporeal anastomosis for laparoscopic right hemico­lectomy. JSLS 2009;13:312–7.

63. Martinez­Mas E, Vazquez­Prado A, Larrocha­Grau M, et al. The impact of low­residue enteral feeding on the healing of colonic anastomoses. Hepatogastroenterology 1993;40:481–4.

64. Tsikitis VL, Holubar SD, Dozois EJ, et al. Advantages of fast­track recovery after laparoscopic right hemicolectomy for colon cancer. Surg Endosc 2010;24:1911–6.

65. Muller S, Zalunardo MP, Hubner M, et al. A fast­track program reduces complications and length of hospital stay after open colonic surgery. Gastroenterology 2009; 136:842–7.

Scientific American Surgery

08/15

gastro operations for colon cancer — 18

66. Basse L, Thorbol JE, Lossl K, Kehlet H. Colonic surgery with accelerated rehabilitation or conventional care. Dis Colon Rectum 2004;47:271–7; discussion 277–8.

67. Kwaan MR, Vogler SA, Sun MY, et al. Readmission after colorectal surgery is related to preoperative clinical conditions and major complications. Dis Colon Rectum 2013;56:1087–92.

68. Killingback M, Barron P, Dent O. Elective resection and anas­tomosis for colorectal cancer: a prospective audit of mortality and morbidity 1976–1998. Aust N Z J Surg 2002;72:689–98.

69. Ghaferi AA, Birkmeyer JD, Dimick JB. Variation in hospital mortality associated with inpatient surgery. N Engl J Med 2009;361:1368–75.

Acknowledgments

Figures 1, 3, and 9 Christine KenneyFigure 2 Alice Y. ChenFigures 5, 6, and 8 Tom Moore