Best Approach

In the elective setting, a medial-to-lateral approach is the author’s preferred approach. However, in the setting of a perforation, the anatomy of the left lower quadrant, pelvis, and retroperitoneum is often distorted. The retroperitoneum at the site of the perforation is often inflamed such that critical retroperitoneal structures can be challenging to identify or kept out of harm’s way. A phlegmon may involve loops of small bowel or densely adhere the colon to the pelvic sidewall. For this reason, a lateral-to-medial mobilization is most useful and safe especially in the setting of benign disease where regional lymph node harvest is not of importance (Fig. 28.3). The colon mesentery needs only to be mobilized enough for resection leaving much of the colonic mesentery in place overlying the retroperitoneum and avoiding injury to critical structures such as the left ureter. The dissection should be started above the pathology typically along the proximal descending colon where the planes are less inflamed. The correct plane is followed as the dissection is extended toward the pelvis.

Identifying the Vascular Anatomy

The inferior mesenteric artery (IMA) is typically preserved during an emergent operation. The takeoff of the IMA occurs roughly at the level of L3 vertebrae. The IMA and its branches are the vascular supply to the hindgut structures including the distal transverse, descending, and sigmoid colon, as well as the rectum. Leaving the IMA intact preserves blood flow to the proximal colon and rectal stump while also avoiding the retroperitoneum and circumventing the potential risk of injury to underlying structures.

Identification of the Left Ureter

Given the left ureter’s close proximity to the rectosigmoid and left pelvic sidewall, it is often at risk for becoming secondarily involved from diverticular inflammation. Therefore, it is particularly vulnerable to injury during emergent surgery for complicated sigmoid diverticulitis. It lies under the parietal peritoneum along the pelvic sidewall and rests on the anterior surface of the psoas muscle (Fig. 28.4a, b). The right and left ureters generally both follow a straight path from the renal pelvis to the pelvic brim and then cross over the iliac vessels to enter the pelvic brim. The right ureter classically traverses the external iliac artery, whereas the left ureter lies slightly more medial and typically crosses the common iliac artery. The ureters then run posterior and inferior along the lateral pelvic sidewall before entering the posterolateral surface of the bladder to form the trigone. If possible, avoiding extensive mobilization in a lateral-to-medial fashion should avoid injury to the ureter and other underlying retroperitoneal structures such as the left gonadal vessels and the hypogastric nerve plexus.

If the underlying disease and circumstances dictate a more extensive retroperitoneal dissection, the ureter must be visualized and dissected out to avoid inadvertent injury. In cases where the ureter is not easily identified, it is prudent to alter the approach and mobilization to ensure that it is visualized prior to mesentery or bowel transection. In certain cases, the ureter may have been mobilized medially and placed on stretch with the mobilized left colon mesentery. Alternatively, it may be involved in a phlegmon and require dissection to free it. The latter cases require a different approach to dissect the colon mesentery safely away from the left ureter to avoid transection. In the non-emergent setting, preoperative ureteral catheters/stents placement can be particularly helpful to aide in laparoscopic palpation of the ureters. Though these stents do not reduce the risk for transection or injury, they do permit for earlier identification of these events and facilitate prompt repair.

Splenic Flexure Mobilization (If Needed)

Splenic flexure mobilization is typically not required when performing an HP unless the patient is morbidly obese and with a thick abdominal wall or PRA is planned. Splenic flexure mobilization is generally performed using a combination of approaches. A lateral-to-medial approach is our preferred approach in the emergency setting. The patient is placed in reverse Trendelenburg position with the table inclined toward the right. Laterally, the peritoneal attachments to the abdominal sidewall and spleen are carefully divided while being mindful not to injure the splenic capsule (Fig. 28.5). Often, there will be close and dense adhesions of the colon to the spleen. The hand-assist technique can also be advantageous in this scenario. The lesser sac can be entered and used to direct the dissection around the splenic flexure and safely mobilize left colon (Fig. 28.6). Dissection continues separating the attachments of the splenic flexure and its mesentery away from the spleen and pancreas.

Resecting the Source of Sepsis

Once the colon is adequately mobilized and the left ureter identified and protected, bowel resection is carried out. In the setting of a large perforation , the proximal and distal colon should be divided laparoscopically to control contamination. The mesentery is then divided using an energy device or stapler. Staying close to the colon will avoid injury to the underlying structures of the retroperitoneum. In the setting of a phlegmon or perforation, tissues are often friable, necrotic, and ischemic with little bleeding. The mesentery is divided caudally until the site of distal transection is reached.

Distal Colon Transection

A critical step in any left or sigmoid resection is identification of a distal transection point. The colon should be soft and viable. If planning a Hartmann’s procedure, then a lengthier rectal stump can be utilized. The superior hemorrhoidal arteries can be left intact ensuring the retroperitoneum is undisturbed facilitating possible reversal of the colostomy in the future.

When planning a primary anastomosis, division is generally performed at the level of the proximal rectum, past the splaying of the tenia coli on the anti-mesenteric surface. For diverticular disease, this minimizes recurrence by transection distal to the high-pressure zone encountered in the rectosigmoid colon. The upper rectum is isolated by creation of a window between the posterior wall of the rectum and mesentery at the proposed transection site (Fig. 28.7a). Once the bare rectum is appropriately dissected and exposed, division is generally performed with an endoscopic stapling device through the RLQ port (Fig. 28.7b). The appropriate stapling load should be chosen based on the thickness and integrity of the tissue to be divided. It may be required to use additional loads of the stapler in some cases.

Integrity and airtightness of the rectal stump staple line may be tested at this point. The stump is submerged under sterile solution, and gentle insufflation per anus is performed. This can be done with a variety of modalities including rigid proctoscopy, flexible sigmoidoscopy, or bulb syringe insufflation. The former two allow for visualization of the mucosa and staple line. Direct laparoscopic visualization during rectal insufflation should confirm appropriate distension of the stump without air leak (visualized bubbles). If air leak is encountered at this point, two options are available. The first is to introduce the spike of the end-to-end anastomotic circular stapler through the defect. The second option is to resect an additional distal margin incorporating the prior staple line. Air testing may then be repeated.

Extraction and Proximal Colon Transection

Prior to extraction, the distal end of the colon is held with a locking grasper and placed under the location of the anticipated extraction site. Potential extraction sites include extension of the periumbilical incision, creation of a Pfannenstiel incision, or extension of the RLQ incision. When performing a minimally invasive HP, the specimen can be extracted through the marked colostomy site. In a patient who has had prior abdominal operations, using a prior incision may be appropriate. Cosmetically, a Pfannenstiel incision may be preferable and may minimize hernia rates [16]. The incision size will vary between 3 and 6 cm but ultimately is determined by the size of the pathology. Once the abdominal wall is opened appropriately and the peritoneal cavity entered, a wound protector is inserted to protect the skin and soft tissue from contamination during externalization and creation of anastomosis.

Through the wound protector, the distal stapled end of the colon and the proximal mobilized colon and mesentery are extracorporealized. The proximal dissection point is predicated upon a number of factors including inflammation, edema, induration, and perfusion. Appropriate maintenance of vascular supply must be assured to minimize risk of ischemia of the anastomosis. Sharp transection of the marginal artery with resultant pulsatile flow from the proximal end is one method to verify and document appropriate healthy vascular tissue. In the elective setting, newer methods including fluorescence imaging may also be utilized to identify well-perfused tissue prior to transection.

Anastomosis and Intraoperative Leak Testing

A double-stapled technique is often employed during a left or sigmoid colectomy. An end-to-end anastomotic (EEA) stapler height is chosen based on tissue thickness and compliance. Common staple heights range between 3.5 and 4.8 mm staples with optimal closure of 1.5–2 mm in height, respectively. When dealing with the rectum, inflamed or not, the authors typically prefer the latter, green loads. The diameter of the stapler will also vary between 21 and 33 mm and may be selected based on the diameter of the proximal and distal bowel as well as the compliance of the patient’s anal tone. Testing of the anastomosis is essential with recent data suggesting the ability to reduce the incidence of missed anastomotic leak [17]. The bowel proximal to the anastomosis is clamped, and an air leak test is performed as described above. Flexible sigmoidoscopy is preferred by the authors as it allows superior visualization of the mucosa and staple line as well as quick resolution of CO₂. If an air leak is encountered, several options exist including direct repair of the anastomotic leak point(s) with or without fecal diversion, takedown and creation of a new anastomosis, or creation of an end colostomy. Choosing the appropriate surgical management of a positive air leak test is dependent on multiple factors and is beyond the scope of this chapter.

Given that risks for anastomotic leak are multifactorial, the absence of a “positive” leak test does not preclude later occurrence of an anastomotic leak. Other factors should be considered when deciding whether to divert including the severity of immunosuppression, worsening hemodynamic instability, difficult dissection or anatomy resulting in increased tension on the anastomosis, malnutrition, and obesity. Routine prophylactic drain placement is not recommended as it was not shown to reduce surgical site infection or anastomotic leaks [18]. Drains should be used selectively in the setting of residual purulent collections or phlegmons or gross feculent spillage.

Considerations During Laparoscopic Hartmann’s Procedure

In certain cases, anatomic, physiologic, or disease processes preclude safe or appropriate anastomosis. In those cases, as above, the distal colon or proximal rectum should be transected and divided using an endoscopic stapling device. If there is any potential for future anastomosis, it is helpful to add tags at the staple line using permanent monofilament suture to ease future identification of the rectal stump. When mobilizing the proximal sigmoid and descending colon, all attempts should be made to minimize excess dissection and mobilization more than is necessary to bring out a tension-free colostomy. This will aide in future Hartmann’s reversal . Similarly, it may be prudent to have localizing ureteral stents placed at the time of Hartmann’s reversal. For more details, please refer to Chap. 20 on Key Steps During Hartmann’s Procedures to Facilitate Minimally Invasive Hartman’s Reversal.

Fistula/Phlegmon in Diverticular Disease

In the case of fistulas between the colon and other intraperitoneal structures or processes involving phlegmonous collections, care should be taken to minimize concomitant injury/resection (Fig. 28.8a). In general, the authors prefer to place preoperative ureteral catheters (or stents) to help in identification of these structures during dissection. Oftentimes, a combination of lateral-to-medial and medial-to-lateral dissection is required. Initiating the dissection with a medial-to-lateral mobilization close to the takeoff of the IMA may help gain access to the retroperitoneal surface and space between the colon and its mesentery and the sidewall due to decreased acute on chronic inflammatory processes in the central mesentery. This will then help in identification of the ureter and other structures more easily than a primary lateral-to-medial dissection. Dissection may then proceed laterally with anterior retraction of the colon and mesentery. In some cases, it may be helpful to initiate the dissection proximally along the descending colon at an area of decreased inflammatory reaction and proceed caudally. Similarly, rectal mobilization with retrograde dissection can also be a helpful adjunct in mobilizing the colon from the pelvic sidewall and ureter. In certain cases, this dissection and separation of the colon to the sidewall and ureter may require manual disruption with a finger-fracture technique. If significant inflammation and/or abscess are encountered (Fig. 28.8b), in certain cases, anastomosis may be precluded or protected with the use of a diverting loop ileostomy.

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