Laparoscopic Left Hemicolectomy



Laparoscopic Left Hemicolectomy


Tonia M. Young-Fadok



Anatomy

True left hemicolectomy refers to resection of the colon from the mid-transverse colon to the junction of the descending and sigmoid colon. This involves resection of the mesenteric expanse that includes the left branch of the middle colic vessels, the inferior mesenteric vein (IMV), and the left colic artery, with preservation of the inferior mesenteric artery (IMA) and the sigmoidal and superior rectal vessels.

In practice, true left colectomy is a relatively uncommon procedure comprising <2% of the colorectal operations performed in the author’s institution. Complete mobilization of the entire left colon (distal transverse, descending, and sigmoid colon) is, however, frequently performed as it is required in order to perform sigmoid and rectal resections with an anastomosis that is not under tension. Thus, this chapter focuses on surgical techniques that describe full mobilization of the entire left colon, including the distal transverse, descending, and sigmoid colon. This mobilization is vital for a tension-free anastomosis after either low anterior resection or total mesorectal excision (TME) with coloanal anastomosis for resection of rectal cancer, although details of operations on the rectum are discussed in another chapter.


Definitions


Extent of Operation

Left colectomy describes resection of the colon from the mid-transverse colon to the junction of the descending and sigmoid colon. Typically, the proximal extent of the procedure would include the left branch of the middle colic vessels, and thus the proximal margin may be to the right of the midline abdomen and falciform ligament, as the middle colic origin is to the right of the midline. The distal extent has no rigid anatomic definition, but is approximately where the descending colon loses its close approximation to the left lateral sidewall of the abdomen, and the sigmoid colon begins its meandering course away from the left lateral peritoneal reflection. Sigmoid colectomy refers to resection of the colon from the junction with the descending colon to the rectosigmoid junction or proximal rectum. Again, this latter landmark has variable definitions. The two most useful definitions are: “where the colonic taenia coalesce” as this can be confirmed by visual inspection, and the other definition is practical, namely, “just below the sacral promontory,” as it is possible to advance a circular (endoanal anastomosis—EEA) stapler to this level.


Laparoscopic Conventions

Naming conventions for laparoscopic colorectal procedures can be varied. The following terminologies are used in this chapter. An operation is laparoscopic if the resection is performed laparoscopically and the main incision is no larger than required to extract the colon specimen.

Laparoscopic-assisted implies that a portion of the case is performed extracorporeally, for example, for a sigmoid resection, once the sigmoid colon is mobilized it is extracted via a 3- to 5-cm periumbilical incision, the proximal resection margin is transected extracorporeally, and the anvil of the EEA stapler is secured with a purse-string suture to secure the anvil, before returning the bowel to the peritoneal cavity to perform the anastomosis under laparoscopic visualization. The incision, however, is usually identical to that used to extract the specimen, so this differentiation is meaningless in terms of incision length.

The other two terms are hand-assisted and hybrid procedures. The author does not believe that these techniques demonstrate “mastery” of surgery, and thus these terms are mentioned here only to be complete. The author believes that these approaches may be useful for the beginner who is adopting these procedures, as a bridge to learning advanced operations, but these techniques are not a substitute for learning advanced techniques and are not used in our fellowship program. In a hand-assisted procedure a 6- to 8-cm incision (the number of centimeter is equal to the surgeon’s glove size) is used to place a device that allows a hand to be inserted into the peritoneal cavity to facilitate the procedure. This is larger than the typical 3- to 5-cm incision used to extract the specimen for a laparoscopic or laparoscopic-assisted operation. In a hybrid procedure, part of the case is performed laparoscopically and part is deliberately performed open, for example, laparoscopic mobilization of the descending colon and splenic flexure in a planned sigmoid resection, followed by resection and anastomosis through a small incision (infraumbilical midline or Pfannenstiel).


Clinical Presentation

Clinical presentation is dependent upon the underlying disease process. Although infrequently performed, true left colectomy may be indicated for polyp and cancer, and rarely for ischemic stricture, segmental Crohn’s disease, lipoma, or diverticulitis confined to the descending colon. Resection of the sigmoid may be indicated in the following disease processes: most commonly in colorectal neoplasia (polyp or cancer), diverticulitis and volvulus, and less commonly for segmental Crohn’s disease, ileocolic Crohn’s disease with fistula to the sigmoid, and diverticular colitis.

Despite these varied pathologies, the colon has a relatively limited way of presenting with a disease process. These presentations can be categorized into asymptomatic, physiologic, and anatomic. Asymptomatic disease may be discovered incidentally on a screening colonoscopy or even a computed tomography (CT) scan (e.g., polyp or cancer), fecal occult blood test (not the standard of care but still used), or barium enema. Physiologic presentations include patients presenting with anemia (polyp and cancer), localized pain and inflammation (diverticulitis), or diarrhea (Crohn’s disease). Anatomic presentation is related to obstruction (circumferential tumor, diverticular stricture, ischemic stricture, or volvulus).


Diagnosis

If a diagnosis of any of the entities described earlier has been made by any means other than a colonoscopy (e.g., flexible sigmoidoscopy, barium enema, or CT scan) most patients will require a colonoscopy to delineate the extent of the process, obtain histological confirmation with biopsies, tattoo the distal margin in the case of cancer and polyp, and rule out other pathology in the colon. Patients with colon cancer require staging studies that typically include CT scan of the abdomen, pelvis and chest (or chest X-ray), liver function tests, and baseline carcinoembryonic antigen (CEA).



Indications

Colon cancer in the absence of metastatic disease is an indication for resection. In the presence of metastatic disease one must balance the burden of disease (i.e., extent of disease and estimated life expectancy) with the patient’s symptoms (e.g., bleeding requiring transfusion, obstruction) and give consideration to resection and colostomy without the increased risks of anastomotic leak in the patient with extensive metastatic disease.

Polyps require resection if they are not amenable to colonoscopic resection and require an oncologic procedure: if they are too large to resect endoscopically, by definition they are large enough to carry a risk of already having undergone malignant transformation, and biopsies from the periphery of the lesion may be unable to sample this.

Guidelines for resection in diverticular disease are in a process of flux: older guidelines suggested resection after two confirmed episodes (i.e., CT scan confirmation), but more recent evidence suggests that episodes do not become more severe with each subsequent attack but stay “true to form,” that is, remain similar in severity for that patient. Thus, surgical intervention should be tailored to the patient based on severity, frequency of attacks, impact on ability to work and travel, and any complications such as abscess or stricture.

In the case of volvulus, the classic teaching is that surgical resection should be recommended after one episode given the high risk of recurrence. In practice, this is often modified, as patients with this entity are frequently high-risk surgical candidates, bedridden, institutionalized, and with multiple comorbidities. If the patient lives close to high-class medical care and symptoms can be recognized promptly, allowing endoscopic decompression, then the management should be tailored to the patient.

The indication for surgical resection in Crohn’s disease is disease refractory to medical therapy. This definition is very much open to the gastroenterologist’s and patient’s interpretations. If a fibrostenotic stricture does not respond to steroids, it is highly unlikely to respond to immunomodulators (such as 6-mercaptopurine and azathioprine) or biologic agents (anti-TNF agents such as Remicade, Humira, or Cimzia), but by the time the patient presents they have often been treated with these escalating medical regimens. It is important to assess parameters of malnutrition (albumin, prealbumin, and weight loss) when determining the operative approach, which may require a temporary ileostomy to protect an anastomosis.


Preoperative Planning

All patients undergoing elective operations have a formal preoperative assessment: evaluation in our preoperative clinic by a trained clinician to rule out issues pertaining to anesthesia; blood tests including electrolytes, complete blood count, and albumin and prealbumin when indicated by history; chest X-ray and electrocardiogram when appropriate; type and screen within 72 hours of operation; and pregnancy test if indicated. When relevant, patients consult with the stoma nurses to mark the most appropriate site for a planned stoma. With regard to use of a bowel preparation, some data suggest this is not necessary, but these data are from open cases. Data from some randomized trials suggest that bowel preparation may not be necessary, but likewise do not indicate a downside of performing a preparation. Laparoscopic handling of the bowel is facilitated by a bowel preparation, and a “completely laparoscopic” approach demands it! A gallon of polyethylene glycol the afternoon before the day of operation, accompanied by a diet restricted to clear liquids is the author’s preference.

On the day of operation, NSQIP guidelines are followed. Patients who do not have a penicillin allergy are given ertapenem 1-g IV within 60 minutes of the incision; no postoperative doses are required. Patients who are penicillin-allergic receive metronidazole 1-g IV and ciprofloxacin 500-mg IV. within 60 minutes of the incision, and one or two doses postoperatively. All patients are given a warming blanket in the preoperative area as this contributes to the maintenance of normothermia intra- and postoperatively.


Surgical Technique


Positioning

Performing a laparoscopic operation is facilitated by correct positioning. There are three key points: (a) steep position changes are used so that the patient must be safely secured to the table; (b) access to the perineum may be required for stapled anastomosis or intraoperative endoscopy; and (c) the position must allow instruments to be used through any of the ports. To ensure that the patient does not slip, a table is prepared with medical grade pink “egg-crate” foam taped to the bed over a drawer sheet placed beneath the foam, to be used for tucking the arms. The patient is placed in a modified combined synchronous position (modified lithotomy). Padded Allen stirrups are used to position the legs so that the thighs have 5 degrees of flexion and are almost parallel to the abdominal wall. This ensures that instruments used in the lower trocars during dissection in the upper abdomen are not hampered by the thighs. The hands are wrapped in foam and tucked adjacent to the torso. A warming blanket is placed over the chest, followed by a folded blanket (to prevent tearing of the warming blanket so that it may be used in the recovery room), and linen tape is wrapped around the patient’s chest and around the table three times. A “tilt test” is then performed by moving the OR table into all the potential extreme positions used during the case to ensure that the patient is safely secured. Bladder and gastric decompression are obtained with a Foley catheter and orogastric tube respectively, the latter being removed at the end of the case.


Technique: Rationale

This technique uses a lateral-to-medial approach, for several reasons. First, the approach is similar to the open approach and trainees recognize the anatomic landmarks more readily. Second, a medial-to-lateral approach involves sacrificing the IMA and the IMV. Although the IMA requires division in the case of sigmoid colon cancer (to obtain an adequate lymphadenectomy specimen), the author’s preference is to preserve it in benign disease, for example, diverticulitis, by dividing the mesentery close to the colon and thus preserving the superior rectal blood supply to the rectal stump. Proximal division of the IMV is not required as part of an oncologic approach, and it is divided selectively, if required, to obtain adequate length of the proximal colon margin to obtain an anastomosis without tension. Third, in a medial-to-lateral approach, the colon is devascularized early in the case leaving ischemic bowel in situ while the case proceeds.

Whether a sigmoid or a left colectomy is being performed, the full mobilization of the left colon is essentially the same. The author routinely mobilizes the splenic flexure for a sigmoid colectomy as this ensures a tension-free anastomosis and facilitates exteriorization of the specimen. Essentially, the sigmoid and descending colon and the splenic flexure are fully mobilized, followed by a decision regarding transection margins in the colon and the vasculature.


Instrumentation

Most of the mobilization is performed with two laparoscopic graspers and scissors. For graspers, the author’s preference is for
Babcock clamps, avoiding the use of ratchet mechanism, but bowel clamps are acceptable. Curved laparoscopic scissors with electrocautery supplied by a trigger switch on the handle avoids the loss of concentration (and balance) associated with the usage of a foot pedal. The retroperitoneal plane is a bloodless plane and use of the scissors mimics the use of electrocautery in an open case, and keeps the surgeon “honest” regarding the plane, that is, there is no temptation to leave the correct plane that can arise with a vessel-sealing device. A vessel-sealing device is useful for division of the splenocolic attachments and the mesentery. Not all vessel-sealing devices are capable of dividing the IMA (7 mm) and the surgeon must be aware of the industry specifications for the instrument being used.

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Aug 2, 2016 | Posted by in GENERAL SURGERY | Comments Off on Laparoscopic Left Hemicolectomy
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