Patient setup . Patient is placed in the split-leg position for all cases
The patient is placed in Trendelenburg position with the left side tilted up, which assists in displacing the small intestine into the upper abdomen. Prior to any mobilization or resection, inspect the abdominal and pelvic cavity to rule out feculent peritonitis and localize abscesses or phlegmons and evaluate their relationship to the sigmoid colon. It is also appropriate to take this opportunity to visualize the pelvis including the relationship of the inflammatory sigmoid mass to the bladder, left pelvic sidewall and retroperitoneum, ovaries, adjacent colon and small bowel loops, and anterior peritoneal reflection. The small bowel should also be thoroughly inspected to assess the degree of peritonitis and the likelihood that a minimally invasive approach is feasible.
Identification of Pathology
The pathology is often identified during diagnostic laparoscopy at which point adjustments to the preoperative surgical plan may be required. In the setting of perforated diverticulitis, the extent of peritonitis will dictate whether minimally invasive approach is feasible. The identification of feculent peritonitis is often difficult to control with minimally invasive techniques, even hand-assist, and is typically associated with conversion to an open procedure. Patients with purulent peritonitis (Hinchey III) may only require laparoscopic lavage.
Those who present with large bowel obstruction may be difficult to resect due to chronic inflammation such that fecal diversion may be the safest option. In this circumstance the entire large and small bowel should be inspected to rule bowel compromise which may present as large serosal tears or even frank perforation. If there is a concern for malignancy, then an intraoperative colonoscopy is warranted if feasible and temporary fecal diversion may be in the patient’s best interest. Subsequently, the patient may undergo appropriate staging, allow inflammation to settle, and subsequently undergo an appropriate oncologic resection in the future. Pathology located in the proximal sigmoid colon or distal descending colon may necessitate mobilization of the splenic flexure for appropriate tension-free anastomosis or fecal diversion.
Minimally Invasive Resectional Approach
Critical Steps of Resection
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
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)
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.
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 . 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 . 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 . 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.