Hemicolectomy

Anatomy and Physiology

Understanding the anatomy involved in hemicolectomy requires knowledge of structures, including the colon, arterial supply, venous drainage, lymphatic supply, peritoneal attachments. Anatomy will be discussed relevant to the right and left hemicolectomy.[4]

Anatomy of the Colon

The colon is comprised of the cecum, appendix, ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, and sigmoid colon. The ileocaecal valve lies between the ileum and cecum. The colon is derived embryologically from the midgut (cecum to two-thirds along the transverse colon) and the hindgut (remaining 1/3rd of the transverse colon to the sigmoid colon). The colon is composed of incomplete sacculations called haustra, and a longitudinal smooth muscle layer lying just below the serosa called the teniae coli. Fatty appendages, termed the appendices epiploicae, are located along the colon.

Right Colon

The right colon starts in a blind-ending pouch called the cecum, located in the right iliac fossa of the abdomen. The ascending colon is covered by a layer of peritoneum covering its anterior and lateral surfaces. The hepatic flexure lies intraperitoneal adjacent to the liver in the right hypochondrium. The paracolic gutter lies lateral to the ascending and descending colon and acts as a collecting point or conduit for free fluid in the peritoneal cavity.

The blood supply to the right colon is via the superior mesenteric artery (SMA) that branches off the abdominal aorta anteriorly at the lower pole of L1. The SMA gives off two main branches supplying the right colon that are the right colic and middle colic arteries. Another branch supplies the terminal ileum and caecum called the ileocolic artery. The marginal artery of Drummond is a branch of the middle colic that forms an anastomosis with a branch from the left colic artery. Venous drainage of the right colon is via the superior mesenteric vein and tributaries that drain into the hepatic portal vein. Lymphatic drainage of the colon is through lymph nodes that lie on the colon surface (epicolic), which drain into the paracolic nodes. Around the arterial branches from named vessels (e.g., branches of the right colic artery) are the intermediate nodes, and along the named vessels themselves are the mesocolic lymph nodes.

Left Colon

The transverse colon is intraperitoneal and is attached to the stomach via the gastrocolic ligament. It is also connected to the greater omentum. The transverse colon has its mesocolon and is relatively mobile within the abdominal cavity. The splenic flexure is a relatively fixed structure owing to the splenocolic ligament which is divided during left hemicolectomy with care to avoid splenic capsular tear.

The descending colon is covered by peritoneum on its anterior and lateral surfaces. Posterior and medial the descending colon is retroperitoneal. The sigmoid colon is surrounded by the peritoneum and attaches to the lateral abdominal wall via the "white line of Toldt." The ureters and kidneys can be identified and protected by beginning dissection at the intersigmoid fossa at the base of the mesosigmoid.

The inferior mesenteric artery (IMA) and its branches supply the distal transverse colon, descending colon (left colic artery), and sigmoid colon (sigmoid branches and superior rectal artery). The right branch of the left colic artery gives rise to the marginal artery of Drummond, which anastomoses with the left branch of the right colic artery and supplies the splenic flexure and distal transverse colon.

The inferior mesenteric vein drains the left colon and drains into the hepatic portal vein after anastomosis with the splenic vein and superior mesenteric vein.

The superior hypogastric plexus lies in close relation to the IMA pedicle at the bifurcation of the aorta and must be preserved during dissection.

Indications

Most commonly, hemicolectomy is performed for colon cancer. Other indications include inflammatory bowel disease, perforation or obstruction of colon cancer, colonic polyp with high malignant potential, cecal volvulus, isolated right or left side diverticular disease, complicated appendicitis involving the appendix base/cecum, ischemic colitis, non-iatrogenic trauma, and iatrogenic trauma (perforation during colonoscopy).[5][6][7][8][9][10][9][8][7][6][5]

Contraindications

Relative contraindications include high predicted mortality associated with patient-specific factors, including cardiovascular or renal disease, age, pre-morbid functional status. The P-possum score can be used as a guide to mortality and should be weighed against the risks of not operating.[11]

Equipment

The following is not an exhaustive list but covers the equipment used in most laparoscopic operations:

• A scalpel with no.11 blade, Langenbach retractors, artery clips
• A 30° laparoscope with light source and monitor
• Gas insufflation equipment
• Hasson trocars 5 mm and 10-12 mm ports
• Three bowel-safe graspers
• Laparoscopic ultrasonic dissector (e.g. harmonic scalpel)
• Electrocautery equipment
• Laparoscopic suction irrigator
• Laparoscopic clips
• Medium wound protector
• Laparoscopic linear cutting stapler
• Standard 75 mm gastrointestinal anastomosis stapler
• Linear noncutting stapler (60 mm)
• Left hemicolectomy: Circular cutting stapler
• Foley catheter

Personnel

Within an operating theatre, the surgical team consists of a lead operator, assisting surgeon, scrub nurse, and theatre assistants. The anesthetic team consists of an anesthetist and an anesthetic assistant.

The workup and interprofessional care for this operation include personnel cancer nurse specialists, stoma care nurses, radiology, histopathology, and ward teams, including doctors, nurses, pharmacists, health care assistants, and administrative staff.

Preparation

Work Up

Routine workup for elective hemicolectomy involves several steps. Initially, fitness for surgery should be assessed in all patients. This involves investigations including full blood count, urea and electrolytes, group and save, electrocardiogram (ECG) where indicated. Additional tests to investigate cardiovascular and respiratory fitness should be assessed if indicated, including spirometry, transthoracic echocardiogram (TTE), and cardiopulmonary exercise testing (CPET).[12]

Bowel Prep

In the absence of obstructing lesions, bowel preparation is administered pre-operatively and limits the effects of an early anastomotic leak. The bowel is most commonly prepared using a combination of sodium picosulphate and magnesium citrate. This product stimulates colonic contraction and reduces sodium/water reabsorption in the distal small bowel. Some alternative bowel preparation methods are discussed in the literature.[13]

Prophylactic Antibiotics

Cefuroxime and metronidazole are commonly administered immediately before the induction of anesthesia. Metronidazole provides cover against Bacteroides fragilis. Cephalosporin is a broad-spectrum antibiotic with action against gut anaerobes. There is a high-level randomized control trial evidence supporting the use of antibiotics to reduce rates of sepsis in colorectal resections. Prolonged use of antibiotics is indicated if heavy soiling has occurred intraoperatively.[14]

Bladder Catheterization

Performed after induction of anesthesia, bladder catheterization allows careful monitoring of fluid balance in the postoperative period.

Technique or Treatment

To obtain local control of colonic lesions and prevent lymphatic spread, radical en bloc resection is accompanied by excision of the supplying lymphovascular pedicle. Lymphatic supply to a region of the colon follows the arterial supply, and hence for oncological reasons division of supplying arteries close to the superior or inferior mesenteric arteries is essential. Right hemicolectomy involves the division of the ileocolic and right colic arteries as they branch from the superior mesenteric artery. The marginal artery of Drummond is also divided. In a formal left hemicolectomy to treat descending or sigmoid colon tumors, the inferior mesenteric artery is divided.

Tumors of the splenic flexure are most commonly managed by extended right hemicolectomy, dividing the ileocolic, right colic arteries, middle colic artery, and right branch of the left colic artery. An extended right hemicolectomy allows an ileo-sigmoid anastomosis, which can be formed tension-free, whereas the anastomosis in a left hemicolectomy would likely be formed under considerable tension between the rectum and right colon. There is debate amongst experts in the field, and a consensus is not yet reached as the best way to manage splenic flexure tumors.[15]

Right Hemicolectomy

A technique for laparoscopic right hemicolectomy will be described below. Open or robotic approaches follow similar fundamental steps.

Patient positioning is in the Trendelenburg position with a left lateral tilt. Following chlorhexidine preparation of the skin, careful sterile draping of the entire abdomen should be performed. A 10 mm port should be inserted infra-umbilically, using an open cut down technique and a Hasson trocar. Common sites include the suprapubic, epigastric, and left lumbar position for an additional 10-12 mm ports. A 30-degree endoscope should be used to acquire the views necessary during the procedure.

Step 1: Mobilization of the Right Colon

The mesentery of the terminal ileum is dissected using diathermy or harmonic device. Medial tension placed on the right colon allows careful dissection of the peritoneum layer covering the right paracolic gutter. The dissection is extended cephalad to mobilize the right colon from caecum to hepatic flexure. Exposure of Gerota fascia encapsulating the kidney occurs and allows dissection along this avascular plane. Further dissection into the retro-peritoneum should be avoided to prevent damage to ureter/kidney/great vessels. As the hepatic flexure is approached the 2 and 3 part of the duodenum is visible. Returning the colon to its' original position facilitates surgeon orientation.

Step 2: Mobilization of the Transverse Colon

The bed is tilted to adopt the reverse Trendelenburg position. The gastrocolic ligament is dissected, and the left upper quadrant (LUQ) port is used to elevate the stomach with a Nathanson retractor allowing further dissection and entry into the lesser sac. As the dissection is continued towards the hepatic flexure, the previous plane of dissection is encountered and met.

Step 3: Control of Mesentery

The right colon is retracted laterally, and the proximal transverse colon is elevated, revealing the mesocolon. The mesocolon is dissected initially at the hepatic flexure between the right colic and middle colic pedicles. The mesocolon overlying the ileocolic and right colic pedicles is dissected, and these arteries are then clipped and divided close to their source.

Step 4: Anastomosis

The extracorporeal anastomosis can be achieved with relative ease compared to the intracorporeal anastomosis and without increasing the size of the wound required for specimen extraction. It further allows for a more accurate assessment of margins. Once the wound is extended and the wound protector inserted, the specimen is brought out with terminal ileum. Commonly a functional end-to-end ileocolic anastomosis is performed. The terminal ileum is divided with linear stapler proximal to the ligament of Treves. The colon is similarly dissected distally to the specimen with a stapling device. Two enterotomies are performed at the ends of the colon and ileum to permit the insertion of the stapling arms. Then a side-to-side anastomosis is achieved with anastomotic stapler, taking care not to include any mesentery. The remaining defect is closed with a linear stapler. Careful inspection of the integrity of anastomosis is crucial, with any deficits requiring oversewing. The "crotch" of the anastomosis is the commonest site of a leak.

Step 5: Closure and Re-inspection

The rectus sheath is closed en mass, insufflation of the abdomen allows laparoscopic visualization of the anastomosis, hemostasis, and irrigation is performed before trochar removal under vision. Many surgeons leave an intra-peritoneal drain near the anastomotic site; however, the evidence fails to identify an advantage to doing so in this type of surgery.[16] The theoretical advantage is to minimize the effects of contamination should a leak occur, or reduce the accumulation of fluid that may become infected.

Left Hemicolectomy

Step 1: Mobilization of the Sigmoid Colon:

A medial to lateral approach is taken, dividing the sigmoid mesentery at its border with the retroperitoneum. The IMA becomes visible, and dissection of avascular planes cranial and caudal to this artery is dissected, allowing circumferential isolation. Care is taken to identify the ureter lying adjacent to the IMA and avoid damage to this structure. For oncological purposes as described above, the IMA is divided close to its junction with the aorta.

Step 2: Mobilization of the Descending Colon:

The ascending colon is mobilized using electro-cautery or ultrasonic dissection techniques up to the splenic flexure. Minimal bleeding should be encountered in the avascular plane between the mesentery and retroperitoneum as above.

Step 3: Mobilization of the Splenic Flexure:

The splenic flexure is mobilized by transecting the gastrocolic ligament gaining access to the lesser sac. This dissection is extended superiorly up to the inferior pole of the spleen, avoiding dissection close to the splenic hilum. Planes medial and lateral to the left branch of the middle colic vessels are dissected, allowing division of this branch. Preservation of the marginal artery of Drummond and the remaining branches of the middle colic artery is ensured while allowing further mesenteric dissection to allow the transverse colon to form an anastomosis in the pelvis.

Step 4: Extracorporeal Anastomosis:

The most common method of anastomosis in left hemicolectomy is an end to end anastomosis via transanal circular stapler. In this technique, the staples are cut from the transverse colon, and the anvil is placed inside the colon, locked in place by a purse-string suture. The stapling device is then inserted per rectum and inserted to pierce the staple line of the rectum. The anvil is locked into the stapling device, and the stapler is deployed. A side-to-end anastomosis or side to side anastomosis as described above can be performed in certain circumstances.[17]

Step 5: Closure and Re-inspection:

The extraction site wound is closed, and the abdomen re-insufflated for inspection of the anastomosis and thorough hemostasis of the surgical field. For both right and left hemicolectomy, to facilitate anastomotic healing, a defunctioning loop ileostomy can be performed.

Complications

Overall complication rates from laparoscopic surgery for colorectal surgery are similar to open surgery.[18] Meta-analysis evidence suggests laparoscopic favors quicker recovery while oncological outcomes are non-inferior. The main troubling complications specific to laparoscopic hemicolectomy will be discussed below, including anastomotic leak, ureteric injury, and conversion to open. Other complications general to surgical procedures will be discussed in less detail.

Anastomotic Leak

Leak rates from laparoscopic right hemicolectomy are around 4% and represent the major risk to morbidity in patients undergoing this operation.[19] Risk factors for a leak can be grouped into local and generalized. General causes include poor nutritional state, anemia, uremia, diabetes, steroid administration, age, smoking status, and sepsis.[20] Local causes include poor blood supply, inappropriate tension, or infection of the anastomosis. Timing and onset of symptoms from a leak can vary and may occur at any time in the first 2 to 3 weeks following the operation. Warning signs include pyrexia, tachycardia, ileus, and hypoxemia, as well as failure to progress post-operatively.[21] If the leak develops further, then local or generalized peritonitis can occur if rapid fecal contamination occurs; the onset of these features is quicker. An anastomotic leak has not been shown to increase the risk of local recurrence or impact disease-free survival.[21] An investigation by CT with water-soluble (oral in right hemicolectomy, rectal in left hemicolectomy) contrast is the gold standard investigation.[22] Results of which must be interpreted within patient context to avoid over-treating a radiological leak. In the patient with systemic deterioration and generalized peritonitis, a return to theatre for laparotomy is essential for source control. In a major disruption, the anastomosis should be taken down and formed into an end ileostomy and mucous fistula. A thorough peritoneal washout should be performed with warm saline. In the systemically well patient, conservative management with bowel rest and antibiotics may be appropriate. Repair of small defects, intra-peritoneal drain, and defunctioning of the anastomosis with a proximal loop ileostomy/colostomy in systemically well patients without generalized peritonitis is another management strategy.[23]

Ureteric Injury

The ureters become difficult to identify in patients with obesity, diverticular disease, inflammatory bowel disease, and those with previous abdominal surgery/resection in close proximity. Preoperative placement of ureteric stents can aid the identification of ureteral injury.[24] Overall ureteric injury remains a rare occurrence.

Conversion to Open

Indications for open surgery include extensive adhesions, T4 tumors with surrounding invasion, hemorrhage. Conversion to open is associated with worse overall survival in curable resections.[25]

Bleeding

Laparoscopic surgery reduces blood loss.[26]

Wound Infection

Wound infection is reduced in laparoscopic surgery.[26]

Clinical Significance

Improving understanding of the steps involved in hemicolectomy facilitates better surgical assistance in trainees. Predicting the next step of the operation is key to help organize equipment, organize the scrub team, retract tissue, and direct the laparoscopic camera.

Understanding the complications involved in hemicolectomy and their detection permits early recognition and management, leading to better patient outcomes.

Enhancing Healthcare Team Outcomes

As discussed above, preoperative assessment is crucial to the identification of patients unsuitable for anesthesia and those who are considered high-risk patients so that a thorough postoperative plan can be put in place preoperatively. The identification of those patients with cardiorespiratory issues requiring high care or intensive care beds is a prime example.

The interprofessional team approach in the workup for colorectal cancer has been shown to improve patient outcomes.[27] A discussion and consensus opinion on the best management strategy is considered vital to modern practice and facilitates communication between all specialties involved in patient care simultaneously.

Enhance recovery programs are well established in recovery from colorectal resections.[28] The setting of recovery aims for each day regarding factors including nutrition, mobility, analgesia, drains, antibiotics, venous thromboembolism prophylaxis and removal of indwelling lines have been shown to decrease time in hospital and associated costs, reduce nursing workload, and is non-inferior in terms of complications, readmission or mortality.

Nursing, Allied Health, and Interprofessional Team Interventions

Cancer nurse specialists provide patient support throughout the patient journey, involved in breaking bad news, providing detailed information regarding the operation and recovery, and many centers now familiarise patients with the intensive care unit/ward environment before the procedure.[29]

Specialized stoma care nurses provide advice and reassurance for patients and monitor stoma function if one is formed during the operation. They play an important role pre-operatively in assessing the patient, familiarizing them with the bag, and marking the stoma site. Following discharge, the stoma care nurse holistically provides ongoing support covering psychological, spiritual, and social needs.[30][31]

Nursing, Allied Health, and Interprofessional Team Monitoring

The role of the nurse is crucial in facilitating inpatient recovery and monitoring for deterioration post-operatively. Hourly observations in recovery until the patient is considered stable allow an assessment of how the patient is recovering post-op with escalation to anesthetic colleagues if required. Nursing monitoring includes regular four hourly vital signs and the use of major early warning scores is key to the escalation of deteriorating patients. Monitoring and accurate charting of patient urine output, drain output, bowel function and nutritional intake are also key elements of inpatient care.