Overview of colon resection

INTRODUCTION — Colon resection is needed to manage a variety of malignant and benign colon lesions, including trauma. Planning colon resection needs to take into account the nature of the lesion and its location within the colon.

The general issues surrounding resecting the colon are reviewed here. Techniques for colon resection are reviewed separately. (See "Right and extended right colectomy: Open technique" and "Left colectomy: Open technique" and "Minimally invasive techniques: Left/sigmoid colectomy and proctectomy" and "Right and extended right colectomy: Minimally invasive techniques".)

INDICATIONS FOR COLON RESECTION — The indications for colon resection include benign and malignant conditions.

Malignancy

●Malignant and premalignant colon lesions (see "Surgical resection of primary colon cancer")

●Appendiceal cancer (see "Epithelial tumors of the appendix", section on 'Adenocarcinoma')

●Colonic carcinoid (see "Staging, treatment, and post-treatment surveillance of non-metastatic, well-differentiated gastrointestinal tract neuroendocrine (carcinoid) tumors", section on 'Colon')

●Colonic gastrointestinal stromal tumors (GISTs) (see "Local treatment for gastrointestinal stromal tumors, leiomyomas, and leiomyosarcomas of the gastrointestinal tract", section on 'Colon and rectum')

●Metastatic tumor (see "Metastatic melanoma: Surgical management", section on 'Gastrointestinal tract')

Benign disease

●Crohn disease (see "Medical management of moderate to severe Crohn disease in adults")

●Colon polyp unresectable through a colonoscope (see "Overview of colon polyps")

●Colonic ischemia (see "Colonic ischemia")

●Colon trauma (see "Traumatic gastrointestinal injury in the adult patient", section on 'Colorectal injuries')

●Fulminant Clostridioides difficile colitis

●Volvulus (see "Cecal volvulus" and "Sigmoid volvulus")

CONTRAINDICATIONS — An absolute contraindication to elective resection may occur when the clinician estimates that the operative risks outweigh the benefits of surgery, which could be due to patient comorbidities or extent of disease. As an example, patients with widespread metastatic disease and asymptomatic primary tumor will not benefit from definitive colectomy and should not be subjected to the procedure. (See 'Medical risk assessment' below and "Surgical resection of primary colon cancer", section on 'Complicated disease'.)

Relative contraindications include those patients with no social support and/or psychological issues where the magnitude of the procedure could be crippling and the patients would not be able to take care of themselves.

PREOPERATIVE EVALUATION

Medical risk assessment — Prior to elective colon surgery, major medical conditions should be identified and optimized before proceeding. (See "Evaluation of cardiac risk prior to noncardiac surgery" and "Evaluation of perioperative pulmonary risk".)

Patients with colon cancer are older and tend to have more comorbidities and a higher incidence of postoperative morbidity and mortality; otherwise, their disease prognosis is comparable to that of younger patients [1]. (See 'Perioperative morbidity and mortality' below and "Overview of the management of primary colon cancer", section on 'Prognosis'.)

In older patients, it is also important to assess nutritional status and the level of social support. The clinician should identify any patient who lives alone to allow social services to identify any relevant issues and identify a nursing facility for temporary placement during the patient's recovery. Until this is settled, elective colectomy can be postponed.

The same factors should be considered for emergency colectomy as for elective colectomy, except that at times there is no time for a complete evaluation due to the nature of the emergency.

Preoperative imaging — Prior to colon resection, regardless of indication, a contrast-enhanced computed tomography (CT) scan of the abdomen and pelvis should be obtained. If the patient has a cancer clinically staged II or higher, then a CT scan of the chest is also warranted. Under most circumstances, contrast-enhanced CT scan should provide adequate information regarding the mesenteric vasculature, such that standard arteriography is rarely needed. (See "Surgical resection of primary colon cancer", section on 'Preoperative evaluation' and "Clinical presentation, diagnosis, and staging of colorectal cancer", section on 'Staging'.)

PREOPERATIVE PREPARATION

Intravenous antimicrobial prophylaxis — The general issues surrounding the use and timing of intravenous antimicrobial prophylaxis for prevention of surgical site infection following gastrointestinal procedures are discussed separately (table 1 and table 2) [2]. Prior to elective colon surgery, we recommend intravenous antibiotic prophylaxis. We do not continue prophylaxis (intravenous or oral) postoperatively. (See "Antimicrobial prophylaxis for prevention of surgical site infection following gastrointestinal procedures in adults" and "Antimicrobial prophylaxis for prevention of surgical site infection in adults", section on 'Timing'.)

Bowel preparation — In patients undergoing elective colon resection, we suggest the use of mechanical bowel preparation combined with oral antibiotics:

●Mechanical bowel preparation is usually accomplished with polyethylene glycol solution (either 4 liters of GoLYTELY or 238 g of MiraLAX in 2 liters of Gatorade).

●Oral antibiotics should be given after the completion of mechanical bowel preparation in the evening before surgery following one of the following regimens [3]:

•Neomycin sulfate 1 gram and erythromycin base 1 gram at 8 PM, 9 PM, and midnight.

•Both neomycin sulfate 500 milligrams and metronidazole 500 milligrams at 9 PM and 11 PM.

•Ciprofloxacin 500 milligrams (250 milligrams if renally impaired) at 9 PM, PLUS metronidazole 500 milligrams at 9 PM and then again at 11 PM.

Our suggestion is consistent with surgical site infection guidelines issued by the American College of Surgeons and Surgical Infection Society (2017) [4] and the American Society of Colorectal Surgeons (2019) [5]. However, the optimal dose of oral antibiotics as a part of bowel preparation is not known, and other experts have suggested alternate regimens.

Traditionally, mechanical bowel preparation was used with oral antibiotics to prepare for all elective colon surgeries [3,6]. Subsequently, several randomized trials reported no benefit from mechanical bowel preparation [7-9], oral antibiotics [10], or both [11]. As a result, the practice of colon resection without preoperative bowel preparation (and without oral antibiotics) became widespread.

However, results from several studies suggest that the use of mechanical bowel preparation combined with oral antibiotics is associated with more favorable outcomes [12-16], despite a potential increase in the rate of C. difficile infection in some [13,17] but not other studies [18]. According to a meta-analysis, preoperative antibiotics were associated with a higher rate of C. difficile infection among four trials but not among six comparative cohort studies. However, the absolute incidence was extremely low at <1 percent [19].

The best data come from three large retrospective cohort studies of the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) targeted colectomy data [14,20,21]. In the largest study, 45,724 elective colectomies with anastomosis were performed from 2012 to 2015: 37 percent after both mechanical bowel preparation and oral antibiotics, 33 percent after mechanical bowel preparation only, 4 percent after oral antibiotics only, and 25 percent with no bowel preparation [20]. Compared with other bowel preparation strategies, the combination of mechanical bowel preparation and oral antibiotics was associated with lower rates of surgical site infection (2.9 versus 4.6 percent with oral antibiotics only, 5.9 percent with mechanical bowel preparation only, and 6.7 percent with no preparation), anastomotic leaks (2.2 versus 2.9, 3.5, and 4.2 percent), overall complications (10 versus 13.2, 15, and 17.3 percent), and 30 day mortality (0.4 versus 0.8, 0.7, and 1.4 percent). By multivariate analyses, the combination of mechanical bowel preparation and oral antibiotics, compared with no preparation, was associated with fewer surgical site infections in right colectomy (odds ratio [OR] 0.40, 95% CI 0.33-0.50), left colectomy (OR 0.57, 95% CI 0.47-0.68), and segmental colectomy (OR 0.43, 95% CI 0.34-0.54); the same combination was associated with fewer anastomotic leaks in left (OR 0.50, 95% CI 0.37-0.69) and segmental colectomy (OR 0.53, 95% CI 0.36-0.80).

Similarly, a 2015 meta-analysis of seven randomized trials showed that, compared with patients who received a mechanical bowel preparation, patients who received oral antibiotics plus a mechanical bowel preparation had a significantly lower rate of overall surgical site infection (7 versus 16 percent) and superficial surgical site infection (5 versus 12 percent) but not deep surgical site infection (4 versus 5 percent) [22]. Another trial published after the meta-analysis found a similar benefit for oral antibiotics [23].

In most studies, oral antibiotics were coadministered with mechanical bowel preparation to a majority of patients. Given the existing data, oral antibiotics are best administered in conjunction with mechanical bowel preparation for bowel preparation before elective colorectal surgery. This recommendation is consistent with the World Health Organization global guidelines for the prevention of surgical site infection [24]. In a network meta-analysis of 38 randomized trials, mechanical bowel preparation with oral antibiotics was associated with the lowest risk of surgical site infection. Oral antibiotics only were ranked as the second best, but based on limited data. There was no difference in surgical site infection rate between mechanical bowel preparation only and no preparation [25].

In the rare situations where mechanical bowel preparation is contraindicated, there is suggestion that oral antibiotics should be administered anyway. In one study, preoperative antibiotics, independent of mechanical bowel preparation, were associated with lower morbidity and mortality rates compared with no oral antibiotics, although only 4 percent of the study cohort received oral antibiotics only [20].

Selective decontamination of the digestive tract (SDD), a concept of using orally administered, nonabsorbable antibiotics and fungicides to eliminate pathogenic bowel organisms, has been shown to benefit patients in the intensive care unit [26] and undergoing esophagogastric [27] or gastrointestinal surgery [28]. In the SELECT trial, a combination of amphotericin B, colistin, and tobramycin administered for six or more days perioperatively in patients undergoing colorectal cancer surgery reduced the overall rate of infectious complications but not anastomotic leaks compared with no oral antibiotics [29]. More data are required before SDD can be recommended for routine use. Until then, our suggestion for oral antibiotics is described above.

Prophylactic ureteral stenting — The key to preventing ureteral injury is intraoperative identification. Placement of ureteral stents can help identify the ureters but will not prevent injury. Some surgeons routinely consult a urologist to have ureteral stents placed. However, a more selective approach may be prudent, only placing ureteral stents for those patients at high risk for ureteral injury, such as those with bulky tumors, obesity, undergoing reoperations (benign or recurrent disease), prior pelvic surgery, and/or prior radiation. (See "Placement and management of indwelling ureteral stents".)

Thromboprophylaxis — Patients undergoing colon resection frequently are at moderate-to-high risk for developing a deep venous thrombosis (DVT) given their age, presence of malignancy, and nature and duration of surgery (table 3) [30].

Patients identified as having moderate-to-high risk of developing a venous thromboembolic event (DVT or pulmonary embolism [PE]) should be given chemical thromboprophylaxis in addition to mechanical prophylaxis. Chemical prophylaxis is typically administered as subcutaneous injections of unfractionated heparin or low-molecular-weight heparin starting either immediately before surgery or shortly thereafter.

In a randomized trial of 376 patients undergoing colorectal surgery, patients who received chemical prophylaxis before surgery had similar rates of DVT postoperatively (1.6 versus 2.6 percent) and at 30 days (1.6 versus 3.6 percent) compared with those who only received chemical prophylaxis postoperatively [31]. The two groups of patients had similar rates of bleeding events that required reoperation (0.5 versus 1.6 percent). No PE was reported in either group. Thus, when the first dose of chemical prophylaxis should be given remains unclear and continues to be dictated by surgeon preferences and local practices.

DVT prophylaxis in surgical patients, including the duration of therapy, is discussed in detail separately. (See "Prevention of venous thromboembolic disease in adult nonorthopedic surgical patients", section on 'Selecting thromboprophylaxis' and "Prevention of venous thromboembolic disease in adult nonorthopedic surgical patients".)

Anticipated splenectomy — When the surgeon anticipates that left hemicolectomy will require splenectomy (eg, large splenic flexure cancers, local invasion of the spleen), vaccination to prevent sepsis should ideally be administered two weeks prior to colon surgery [32]. Specific vaccines and vaccine schedules are discussed elsewhere. (See "Prevention of infection in patients with impaired splenic function", section on 'Vaccinations'.)

MINIMALLY INVASIVE COLON RESECTION — Several systematic reviews and meta-analyses of randomized trials have compared outcomes for open versus laparoscopic colectomy for patients undergoing resection for colon cancer, diverticular disease, and colitis [33-38]. Although laparoscopic colectomy may take longer than open colectomy, it is associated with short-term benefits, fewer complications, and no differences for long-term outcomes. Thus, for patients with uncomplicated localized colon disease not involving or invading adjacent organs, and who have not had prior extensive abdominal surgery, we suggest laparoscopic colectomy rather than open colectomy whenever a surgeon experienced with advanced laparoscopic colectomy techniques is available, provided there are no contraindications to the technique (eg, severe pulmonary disease).

Short-term (perioperative) outcomes — Laparoscopic colon surgery has been associated with a lower perioperative morbidity in most studies and a lower perioperative mortality in some reports.

In a review of National Surgical Quality Improvement Program (NSQIP) data that included 12,455 laparoscopic and 33,190 open colectomies performed between 2005 and 2008, overall morbidity was 34.9 percent for open colectomy and 19.9 percent for laparoscopic colectomy [39]. In a separate review of the same database, patients undergoing laparoscopic colectomy between 2006 and 2007 had significantly fewer superficial wound infections (6.6 versus 10.3 percent), deep wound infections (1.0 versus 2.4 percent), organ space infections (2.4 versus 4.3 percent), and wound dehiscence rates (0.85 versus 2.7 percent) [40].

In another study using the same dataset (2005 to 2008), patients who underwent laparoscopic surgery were 2.3- to 5.5-fold less likely to have a severe complication (Dindo-Clavien Class 4 or 5 (table 4)) than those who underwent open surgery [41]. The odds ratio remained between 1.6 and 2.2, favoring laparoscopic surgery after multivariable adjustment [41].

Long-term outcomes — Laparoscopic surgery is associated with less intra-abdominal adhesion formation, which can reduce the risk of postoperative bowel obstruction. The best evidence comes from a 2016 meta-analysis of 24 randomized trials and 88 observational studies. Compared with open surgery, laparoscopic surgery was associated with fewer early (106 studies, odds ratio [OR] 0.62, 95% CI 0.54-0.72) and late (12 studies, OR 0.61, 95% CI 0.41-0.92) postoperative bowel obstructions [42].

Laparoscopic colectomy can be performed with the single-incision technique or the standard multiport technique. In a randomized trial involving 200 patients, single-incision laparoscopic colectomy was not superior to standard laparoscopic colectomy except for requiring a shorter total skin incision length (4.4 versus 6.8 cm) [43]. Single-incision laparoscopic techniques are discussed elsewhere. (See "Abdominal access techniques used in laparoscopic surgery".)

Robotic colectomy — Robot-assisted laparoscopic procedures combine the advantages of the laparoscopic approach (eg, less postoperative pain, faster recovery) with the advantages of the open approach (eg, high-quality three-dimensional vision, restoration of the eye-hand-target axis) [44-46]. The disadvantages of robotic surgery include high cost, long intraoperative setup times, and long procedure times [47]. There are no data from randomized trials comparing survival and disease-related outcomes for procedures performed by the robotic-assisted approach with either the open or the laparoscopic approach.

Nevertheless, a population-based study of Medicare beneficiaries undergoing colectomy reported that the proportional use of robotic colectomy rose from 0.7 percent in 2006 to 10.9 percent in 2010 in all hospitals and from 0.8 to 32.8 percent in hospitals with the highest adoption rate of robotic colectomy [48]. In those hospitals, robotic colectomy displaced laparoscopic colectomy (43.8 to 25.2 percent) more than it did open colectomy (55.4 to 41.9 percent). In this study, robotic colectomy was associated with minimal safety benefit over open colectomy (17.6 versus 18.6 percent of overall complication rate) and no benefit over laparoscopic colectomy. Another study reported that the use of robotic colectomy increased from 2.5 to 16.3 percent from 2012 to 2018 using data from the Michigan Surgical Quality Collaborative [49].

Techniques of minimally invasive colorectal resection are discussed elsewhere. (See "Minimally invasive techniques: Left/sigmoid colectomy and proctectomy" and "Right and extended right colectomy: Minimally invasive techniques".)

COLON RESECTION

Types of colon resection — Types of colon resection are described below. Resections are based anatomically on the location of the lesion, blood supply (figure 1 and figure 2) and, for malignant lesions, the lymphatic drainage of the colon (figure 3). Resection margins must be chosen to ensure adequate blood supply in the remaining colon. (See "Left colectomy: Open technique" and "Right and extended right colectomy: Open technique".)

●Segmental colectomy – Segmental resection, which removes only an affected portion of bowel, can be performed when a lesser resection is indicated (eg, trauma, diverticulitis), provided the anastomosis will be performed in well-vascularized bowel (figure 4).

●Ileocecectomy – Ileocecectomy resects a portion of the distal ileum and the cecum (figure 5).

●Right hemicolectomy – Right hemicolectomy removes a portion of the distal ileum, the cecum, ascending colon, and the transverse colon to the right of the middle colic artery (figure 6A-B).

●Extended right hemicolectomy – Extended right hemicolectomy expands right hemicolectomy to include the transverse colon over to the splenic flexure (figure 7).

●Transverse colectomy – Transverse colectomy removes the transverse colon (figure 8). Transverse colectomy is uncommonly performed for malignancy as cancers are generally to the right or left of the midline and, thus, an extended right or left hemicolectomy should be performed to achieve an adequate lymphadenectomy.

●Left hemicolectomy – Left hemicolectomy removes the transverse colon to the left of the middle colic artery and the left colon and sigmoid colon to the level of the upper rectum (figure 9A-C).

●Sigmoidectomy – Sigmoidectomy removes the sigmoid colon (figure 10).

●Total colectomy – Subtotal colectomy removes most of the colon including most of the sigmoid colon, whereas total abdominal colectomy removes the entire intraperitoneal colon (figure 11).

Benign versus malignant disease

The extent of colon resection depends upon the disease process being treated. (See 'Types of colon resection' above.)

●Benign lesions are generally removed using a segmental resection or hemicolectomy (right or left). For localized benign conditions of the colon (eg, trauma, diverticular disease, inflammatory bowel disease), a segmental resection with a primary anastomosis in well-vascularized colon and a limited mesenteric resection can be performed. Diverticular disease, typically treated with a sigmoidectomy, may require a left hemicolectomy if the descending colon is unsuitable for an anastomosis. Extended resection (extended right or left colectomy) or subtotal or total colectomy may be needed for more extensive benign disease of the colon (eg, inflammatory bowel disease, diverticular disease, fulminant C. difficile colitis). For large polyps that require resection because of a possible malignancy, the authors perform a formal cancer operation.

●Malignant lesions located in the appendix, cecum, and ascending colon can be resected by a right hemicolectomy. Malignant lesions located in the hepatic flexure or proximal to the midtransverse colon are resected with an extended right colectomy. Malignant lesions of the left colon are typically resected with a left hemicolectomy. For malignant lesions of the splenic flexure, a limited resection extending from the transverse to the sigmoid colon can be performed, but the pedicle of the left colic artery and the first sigmoid branch should be included in the specimen. A small number of transverse tumors may be amenable to transverse colectomy. The surgical margins for a curative resection for colon cancer should be at least 5 cm from the tumor on both sides [50].

The extent of the mesenteric resection also varies according to whether the resection is being performed for benign conditions or malignancy. Figures that show these differences are given in the section above. (See 'Types of colon resection' above.)

●For benign disease including trauma, mesenteric vessels can generally be divided close to the mesenteric border of the colon since it is unnecessary to resect draining lymph nodes. However, in settings of severe mesenteric inflammation (eg, diverticulitis, inflammatory bowel disease) and thickening of the mesentery near the bowel wall, a more extensive mesenteric dissection may be necessary.

●For malignancy, a complete mesocolic resection ligates the mesenteric vessels close to their root to optimally resect the lymphovascular tissue. As an example, for left colectomy, the inferior mesenteric artery is ligated at its origin from the aorta and the inferior mesenteric vein is ligated at the level of the pancreas; the mesentery and draining lymphatics are removed with the vascular pedicle. Whether to perform a complete mesocolic resection for right colectomy remains controversial, and available data are presented elsewhere. (See "Surgical resection of primary colon cancer", section on 'Cecum or right colon'.)

BOWEL ANASTOMOSIS — There is insufficient evidence to suggest that the method of performing the colon anastomosis (hand sewn or stapled) or its configuration (end to end, end to side, side to side) is better functionally or less likely to leak [51]. Experience, surgeon preference, and availability of equipment dictate the type of anastomosis a surgeon performs in a given situation. Stapling the anastomosis requires less time to perform and offers the potential for reduced fecal contamination but at times may not be practical. Specific types of anastomoses (ileocolic, colo-colonic, colorectal) are discussed separately. (See "Right and extended right colectomy: Open technique" and "Left colectomy: Open technique" and "Bowel resection techniques".)

Stapled versus sutured anastomosis — Stapled and hand-sewn anastomosis have long been considered equivalent and to be chosen by the operating surgeon depending on personal preference, past experience, and the anatomical/clinical conditions of the patient. Until data demonstrate conclusively the superiority of one technique, we continue to recommend that surgeons become facile with both techniques and tailor their use to each individual patient situation.

The surgeon has to be comfortable with the technique they are using and perform it meticulously. As an example, when closing the common enterotomy with a stapler, one staple line should not lie on top of the other. With either technique, if there is any question of ischemia or any other problems (eg, the anastomosis does not look "right") at the end of the anastomosis, the surgeon must take the time to take it down and redo it. (See "Bowel resection techniques".)

Ileocolic anastomosis following a right hemicolectomy is the most studied anastomosis because its technique is standard and its leak rate the lowest among all colorectal procedures. However, trials and observational studies draw completely opposite conclusions:

●A 2011 Cochrane review of 11 trials (1125 ileocolic anastomoses; 441 stapled, 684 handsewn) reported fewer leaks following stapled anastomosis than handsewn anastomosis (2.5 versus 6.1 percent; odds ratio [OR] 0.48, 95% CI 0.24-0.95) [52]. A subgroup analysis of cancer patients confirmed that there were also fewer leaks with stapled anastomosis (1.3 versus 6.7 percent; OR 0.28, 95% CI 0.10-0.75).

●On the contrary, several observational studies from Europe reported more leaks following stapled anastomosis than handsewn anastomosis [53-57]. As an example, a study from Denmark analyzed 1414 patients who underwent colon surgery for right-sided cancer [56]. The leak rates following stapled and handsewn anastomosis were 5.4 and 2.4 percent, respectively. All of these studies were large (involving from 400 to 3400 patients) and contemporary (published between 2015 and 2019); most patients underwent surgery for cancer or Crohn disease. Stapled anastomosis was associated with more leaks with an odds ratio in the range of 1.43 to 2.41. However, these results should be interpreted with caution as the study populations are heterogeneous and the surgical techniques are not standardized.

Intraoperative anastomotic perfusion assessment — Although inadequate blood supply is believed to be a major risk factor for bowel anastomotic complications, para-anastomotic perfusion is most often only assessed subjectively by the surgeon. Indocyanine green (ICG) angiography using near-infrared (NIR) imaging has emerged as a new technology that permits real-time assessment of intestinal microvascularization. (See "Instruments and devices used in laparoscopic surgery", section on 'In vivo fluorescence imaging'.)

NIR imaging with ICG has been associated with reduced rates of anastomotic complications in observational studies [58-61] but not randomized trials. In a meta-analysis of 25 comparative studies, the use of intraoperative ICG fluorescence angiography was associated with a reduction in all grades of anastomotic leaks (OR 0.39, 95% CI 0.31-0.49) and a reduction in the length of hospital stay [62]. For low or ultra-low rectal anastomosis, the odds ratio of developing anastomotic leakage was 0.32 (95% CI 0.23-0.45). ICG fluorescent injection was not associated with any side effects or prolongation of operative time.

If its efficacy in reducing anastomotic complication can be confirmed by randomized trials (at least one is under way [63]), ICG angiography using NIR imaging may become a useful tool for assessing perfusion before and after a bowel anastomosis.

Primary closure versus ostomy — Most patients can have a primary colon anastomosis to restore continuity of the bowel. Although a primary anastomosis is the preferred goal for patients with perforated or obstructing lesions, it may not be possible if the patient is too sick to undergo a definitive procedure (eg, intraoperative medical instability, generalized peritonitis), in which case a staged approach may be needed if the latter were used.

Drain (not routine) — We do not routinely place drains in the abdomen or pelvis after colon resection due to a lack of clinical benefit. A meta-analysis of four trials that compared drained versus undrained patients undergoing colorectal anastomosis found similar rates of clinical leaks, radiological leaks, mortality, overall morbidity, wound infection, pelvic sepsis, bowel obstruction, and reintervention for abdominal complications [64].

An international prospective cohort study of 1805 patients undergoing elective colorectal surgery reported that drains were not associated with reduced rates (OR 1.33, 95% CI 0.79-2.23) or earlier detection (hazard ratio [HR] 0.87, 95% CI 0.33-2.31) of collections [65]. Drains were associated with delayed hospital discharge (HR 0.58, 95% CI 0.52-0.66) and an increased risk of surgical site infections (OR 2.47, 95% CI 1.50-4.05).

POSTOPERATIVE CARE AND FOLLOW-UP — Postoperative management of colectomy patients emphasizes reduced perioperative fluid volume, early postoperative feeding, and early ambulation [66-73]. (See "Enhanced recovery after colorectal surgery".)

The majority of patients tolerate partial colectomy with only minor physiologic consequences related to fluid absorption, such as temporary loose stools [74-76]. There is great variability in frequency, with most patients having a minimal increase in frequency, but some have at least a temporary increase to four or more movements per day. Such patients may benefit from the addition of dietary fiber and, when necessary, an antimotility agent. The remaining colon will often adapt over a four-to-six-month period, gradually returning to a more normal bowel pattern.

At the time of discharge from the hospital, the patient is instructed to avoid strenuous activity and heavy lifting for four to six weeks following surgery but is encouraged to participate in light activity, such as walking, and to return if unexpected symptoms such as significant abdominal pain, nausea/vomiting, obstipation, fevers and chills, or signs of wound infection including redness or drainage occur. Otherwise, patients should return for an outpatient visit 10 to 14 days after hospital discharge for wound examination and/or skin staple removal. Patients who undergo colectomy for cancer should be discharged with 28 days of thromboembolic event prophylaxis, starting from the day of surgery.

PERIOPERATIVE MORBIDITY AND MORTALITY — Perioperative morbidity and mortality following colon resection depends, to a large extent, upon whether the procedure is performed under elective or emergency circumstances (eg, obstructing lesion, bowel perforation) and the patient's associated comorbidities (eg, cardiopulmonary disease, multiple trauma). Patients with colon cancer are older and tend to have more comorbidities and as a result have a higher incidence of postoperative morbidity and mortality [1]. Longer-term survival is disease specific (eg, colon cancer) and is reviewed in a separate topic review for various conditions [1,77-79]. (See "Overview of the management of primary colon cancer", section on 'Prognosis'.)

Complications of colectomy include surgical site infection, ureteral injury, anastomotic leak, intra-abdominal abscess, enteric fistula, bleeding, and postoperative bowel obstruction. The frequency and management of the intra-abdominal complications, including anastomotic complications, of colorectal surgery are reviewed elsewhere. (See "Management of anastomotic complications of colorectal surgery" and "Management of intra-abdominal, pelvic, and genitourinary complications of colorectal surgery".)

●A later study included data from the University Health System Consortium Data Base on patients undergoing right (n = 9336) or left (n = 5744) hemicolectomy for colon cancer at academic medical centers between 2002 and 2006 [80]. The overall complication rate was comparable to that reported by the VA study and similar for right and left hemicolectomy (26.8 and 28.3 percent, respectively). The most common complications were wound and pulmonary related. Thirty-day in-hospital mortality rates were 1.4 and 1.3 percent for right and left hemicolectomy, respectively, much lower than in the VA study [80].

●The frequency of surgical site infection after colorectal surgery for benign and malignant disease was evaluated in a review from the National Surgical Quality Improvement Program (NSQIP) of patients in the database between 2006 and 2007. The overall rate of surgical site infection was 14 percent and was significantly lower in patients undergoing laparoscopic compared with open colectomy (9.5 versus 16.1 percent) [40]. (See 'Minimally invasive colon resection' above.)

●Patients with obesity have more postoperative complications after colon surgery. In a retrospective review of 1048 patients undergoing colon resection for cancer, a one-category increase in body mass index (eg, from normal weight to overweight, or from overweight to obese) (table 5) was associated with a 1.6-fold increase in wound infections and a 1.5-fold increase in slow wound healing [81]. The risk of fascial dehiscence was also increased in patients with a higher body mass index, but only with open procedures.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Colorectal cancer" and "Society guideline links: Colorectal surgery for cancer".)

SUMMARY AND RECOMMENDATIONS

●Indications for colon resection – Colon resection is needed to manage benign disease (eg, volvulus, ischemia, endoscopically unresectable polyps), traumatic injuries, and malignant tumors of the colon. (See 'Indications for colon resection' above.)

●Preoperative evaluation – Assessment of the patient prior to elective colon resection includes evaluation of medical comorbidities, functional status, and social support. Planning colon resection takes into account the nature of the lesion, its location within the colon, and the status of the colonic circulation. Regardless of indication, we obtain a contrast-enhanced computed tomography (CT) scan of the abdomen and pelvis and include a CT scan of the chest if the patient has a colon cancer staged II or higher. (See 'Preoperative evaluation' above.)

●Preoperative bowel prophylaxis

•Mechanical bowel preparation and oral antibiotics – In patients undergoing elective colon resection, we suggest mechanical bowel preparation combined with oral antibiotics rather than mechanical bowel preparation alone or no preparation (Grade 2C). Typical oral antibiotics regimens are neomycin plus erythromycin or neomycin plus metronidazole. Administering oral antibiotics independently of mechanical bowel preparation is of unproven benefit. (See "Antimicrobial prophylaxis for prevention of surgical site infection following gastrointestinal procedures in adults" and 'Bowel preparation' above.)

•Intravenous antibiotics – In addition, we recommend preoperative intravenous antibiotic prophylaxis immediately prior to colon resection rather than no intravenous antibiotics (Grade 1B). (See 'Intravenous antimicrobial prophylaxis' above.)

●Minimally invasive colon resection – For patients with uncomplicated colon disease not involving or invading adjacent organs, and who have not had prior extensive abdominal surgery, laparoscopic colectomy rather than open colectomy is suggested whenever a surgeon experienced with advanced laparoscopic colectomy techniques is available, provided there are no contraindications to abdominal insufflation. (See 'Minimally invasive colon resection' above.)

●Extent of colon resection – The different types of colon resections are based upon the arterial anatomy of the colon to ensure adequate blood supply in the remaining colon. For malignant diseases, the surgical margins should be at least 5 cm from the tumor on both sides. Examples of conditions or lesions resected using each of these are listed below. (See 'Types of colon resection' above.)

•Segmental resection – Focal traumatic colon injury

•Ileocecectomy – Benign disease

•Right hemicolectomy – Right-sided cancer

•Extended right hemicolectomy – Proximal transverse colon cancer

•Transverse colectomy – Extensive trauma

•Left hemicolectomy – Left-sided colon cancer

•Sigmoidectomy – Refractory sigmoid diverticulitis

•Subtotal/total colectomy – Fulminant Clostridioides difficile

●Mesenteric resection – The extent of the mesenteric resection varies according to whether the resection is being performed for benign conditions or for malignancy. For benign disease including trauma, mesenteric vessels can generally be divided close to the mesenteric border of the colon, provided the anastomosis will be well vascularized. For malignant tumors, the mesenteric vessels should be ligated close to their origin to optimally resect the lymphovascular tissue. (See 'Benign versus malignant disease' above.)

●Bowel anastomosis – The experience and preference of the surgeon generally dictates whether the colon anastomosis is hand-sewn or stapled or configured end to end versus end to side or side to side. Restoring gastrointestinal continuity using a primary colon anastomosis is the goal for most patients following colon resection. For patients undergoing colon surgery for perforated or obstructing colon lesions, definitive surgery may not be possible, and a staged approach may be needed. (See 'Bowel anastomosis' above.)

●Postoperative care – For postoperative management, a "fast-track" protocol includes oral feedings on postoperative day 1, solid foods on postoperative day 2, and early ambulation. (See 'Postoperative care and follow-up' above and "Enhanced recovery after colorectal surgery".)

●Morbidities – Complications of a colectomy include surgical site infection, ureteral injury, splenic injury, anastomotic leak, intra-abdominal abscess, enteric fistula, bleeding, and postoperative bowel obstruction, among others. (See 'Perioperative morbidity and mortality' above and "Management of anastomotic complications of colorectal surgery" and "Management of intra-abdominal, pelvic, and genitourinary complications of colorectal surgery".)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Miguel A Rodriguez-Bigas, MD, who contributed to earlier versions of this topic review.