Colorectal Surgery in the Obese and Morbidly Obese Patient: Preoperative Strategies and Surgical Techniques
For laparoscopic right colectomy, a Veress needle insertion is used at Palmer’s point in the left upper quadrant to gain insufflation. We utilize a four-port laparoscopic technique, but even within our practice, some variation in port placement does occur. In general, the laparoscopic ports should be separated by 10–12 cm. Figure 32.3 depicts a typical port placement scenario. Initially, a trocar is placed in the center of the abdomen equidistant from the pubic symphysis and the xiphoid process. Trocar size at this location will depend on the surgeon’s preference regarding camera size (5 vs. 10 mm). The lower midline port is placed 10–12 cm below the central camera port, and sometimes there is the opportunity to place this through the intended Pfannenstiel extraction site. The left lower quadrant port is placed between the camera port and the anterior superior iliac spine. Finally, the left upper quadrant 5 mm port is placed (Fig. 32.3). In this port arrangement, the left lower quadrant 12 mm port site can also be enlarged for specimen extraction depending on the preference of the surgeon.
The patient is placed in Trendelenburg position with the left side down. The small bowel is swept to the patients left to expose the ileocolic pedicle which is further defined by having the assistant elevate the cecum anteriorly and inferiorly. For a medial to lateral approach, the mesentery is scored below the ileocolic pedicle, and the plane is developed bluntly to separate the mesocolon from the retroperitoneum (Fig. 32.4a, b). The duodenum is identified and protected, and the ileocolic pedicle is divided (Fig. 32.5a, b). The omentum is then freed from the transverse colon, and the hepatic flexure is taken down from a medial to lateral fashion. Finally, the white line of Toldt is released, and the ileal mesentery is freed from its posterior attachments. The mesentery of the transverse colon and ileum are divided with the energy device and the bowel divided with laparoscopic staplers.
We prefer an intracorporeal anastomosis (ICA) in all patients, and evidence suggests that ICA in obese patients is associated with a reduced risk of postoperative incisional hernia presumably because the specimen is not being removed via a midline incision . For the intracorporeal anastomosis, multiple techniques can be applied. The anastomosis can be set up antiperistaltic or isoperistaltic. In both techniques, the ends of the colon and ileum are aligned side by side. Enterotomies are created in the ileum and colon using a hook electrocautery. The laparoscopic stapler is used to create a common channel. For closure of the common enterotomy, an additional staple fire can be used; this technique is reproducible, is reliable, and mirrors the open technique of a totally stapled side-to-side anastomosis. Alternatively, the common enterotomy can be closed with sutures (Fig. 32.6a–d). An intracorporeal handsewn closure of the common enterotomy is also effective and has the benefit of cost savings compared with stapled closure.
Once the anastomosis is complete, a small Pfannenstiel incision is made, and the specimen is extracted through a wound protector. Alternatively, the left lower quadrant port site may be enlarged via a muscle splitting incision and the specimen removed via that site. Please refer to Chap. 14 on options for ileocolonic reconstruction for more details on various anastomotic techniques.
Laparoscopic Left Colectomy
For left colectomy, the room is set up to facilitate all personnel and provide access to the rectum. Abdominal insufflation is again gained through a Veress needle technique. The camera port placement is identical to what is described above. The 12 mm port is placed now 10–12 cm from the camera port on a diagonal line from the camera to the right anterior superior iliac spine. Five millimeter ports are next placed 10–12 cm from the camera port in the right upper quadrant midclavicular line and superior midline below the xiphoid process (Fig. 32.7).
Next, the dissection can begin either above or below the level of the inferior mesenteric artery (IMA). The authors prefer to begin above the level of the IMA at the inferior mesenteric vein (IMV). The dissection is begun by incising the peritoneum just below the IMV, which is found adjacent to the ligament of Treitz (Fig. 32.8). Again, blunt dissection is used to separate the mesocolon from the retroperitoneum. As the dissection progresses, the IMV is clipped and divided which will allow for complete mobilization of the splenic flexure. The attachments of the splenic flexure are released in a medial to lateral fashion as well. This is performed by dissecting over the anterior surface of the pancreas and entering the lesser sac. Anecdotally, we have found that this seems to be an easier approach to splenic flexure mobilization in obese patients; however, care must be taken not to open a plane posterior to the pancreas and risk splenic vein injury. All attachments of the distal transverse colon and splenic flexure can be safely divided with this technique.
The dissection is next moved to below the level of the IMA. The sigmoid colon is elevated to the abdominal wall and the IMA put on stretch to aid in identification. The mesentery below the IMA is scored from the IMA to the sacral promontory and blunt dissection again utilized to free the mesocolon from the retroperitoneum (Fig. 32.9a, b). Here, the ureter and gonadal vessels must be identified prior to IMA division. Following division of the IMA, the white line of Toldt is incised to release the colon from the abdominal wall, and the omentum is elevated off the transverse colon as needed. The mesorectum and rectum are divided intracorporeally as this approach is straightforward, and this can be very challenging to perform extracorporeally via the Pfannenstiel incision in obese patients. Similarly, the proximal mesocolon is divided intracorporeally as this would also be very challenging to divide extracorporeally via the Pfannenstiel incision in an obese patient.
A Pfannenstiel extraction site is created, a wound protector placed, and the distal end of the specimen is brought out. Field isolation is employed, and the colon is divided at the proximal margin extracorporeally. An anvil is secured in the proximal colon, and it is returned to the abdomen. Next, a transanal circular stapler is used to anastomose the colon and rectum. Flexible endoscopy is used to test the anastomosis for bleeding and air leak testing.
Laparoscopic Total Colectomy
For laparoscopic total colectomy , our ports are typically placed in a box configuration as depicted in Fig. 32.10. This configuration allows for access to all four abdominal quadrants, allows for both the surgeon and assistant to work simultaneously, and is similar to port placements for both the right and left laparoscopic colectomies.
Pitfalls and Troubleshooting
Laparoscopic colectomy often involves working in multiple quadrants within the abdomen (Fig. 32.11). Improper port placement can severely limit your ability to access each quadrant of the abdomen without undue stress put on the patient’s abdominal wall as well as the surgeon. It is critical to consider the trajectory of the laparoscopic port during placement. The patient’s abdomen exists as a dome once insufflated; the surgeon’s goal should be to have their port placement be exactly perpendicular to the skin and abdominal wall at the point of insertion. This insertion results in the least amount of trauma to surrounding tissue and the most ergonomic positioning for working in multiple quadrants within the abdomen. One technique that can help achieve this positioning is to push trocars directly forward until the tip of the trocar engages the fascia. After that, it is appropriate to begin twisting motion required of spreading trocars for insertion. Twisting prior to engaging the fascia can often result in skiving tangentially in the subcutaneous fat prior to engaging the fascia. It is easier to skive the trocar in obese patients given the greater distance between the skin and abdominal wall.
Identification of Anatomic Landmarks
Proper identification of vascular landmarks and critical structures such as the ureters is essential for successfully completing a laparoscopic or open colectomy. However, obesity can challenge identification of these landmarks secondary to a thickened and shortened mesentery. Indeed, some studies have shown that it is the presence of excessive visceral fat, rather than BMI, that is highly predictive of postoperative complications in colon resection [42, 43]. Furthermore, men tend to carry the obesity in the mesentery rather than the subcutaneous tissue . This can generally make for a more challenging colon resection. In the event it is difficult to expose a given vascular pedicle, i.e., the ileocolic pedicle, inferior mesenteric vein, or inferior mesenteric artery, the surgeon should always review factors that can assist exposure. Proper bed positioning can often be critical for exposing vascular anatomy. Proper positioning will allow the small bowel to fall away from structures of interests. Adequate assistance is also critical, often it may be necessary to use an extra 5 mm assistant port for laparoscopic colectomy to aid in retraction. Those two factors can often make a large difference in avoiding a conversion for inability to progress during a laparoscopic colectomy.
Failure to Progress
If in the course of a minimally invasive operation the surgeon determines that there has been failure to progress based on disease burden, unclear anatomy, unfavorable anatomy, bleeding, or other factors, conversion to an open approach is recommended. Advocates for hand-assisted laparoscopy (HALS) suggest this may reduce the risk of conversion to an open surgery. With regard to HALS in obese patients, a retrospective single-center study did demonstrate a decreased conversion to open procedure in patients, BMI > 30, undergoing hand-assisted laparoscopy when compared with conventional laparoscopic resection . Subgroup analysis in that study demonstrated this benefit was only statistically significant in patients undergoing right colectomy. Interestingly, differences in conversion rate did not reach statistical significance in the left colectomy, sigmoid colectomy, total colectomy, proctocolectomy, low-anterior resection, or abdominoperineal resection subgroups.
Minimally Invasive Proctectomy: A Word of Caution
Minimally invasive total mesorectal excision in an obese male patient is generally regarded as one of the most challenging surgeries that a colorectal surgeon will face. The choice of which minimally invasive approach a surgeon should take (laparoscopic, robotic, transanal TME) depends on what the surgeon is comfortable performing and what the surgeon has the most experience in performing. In the UK Medical Research Council (MRC), trial of conventional vs. laparoscopic-assisted surgery in colorectal cancer (CLASICC), surgeons were required to have performed at least 20 laparoscopic resections to enter the study . Over the study period, the rate of conversion to open surgery fell from 38% to 16% suggesting that an experience of 20 cases was not enough. Given a general surgeon in the United States performs an average of 11 colon resections annually , and that not all cases are candidates for laparoscopic surgery, it could take a surgeon years to gain adequate experience to perform these cases.
In addition , it has been demonstrated that the hospital experience with minimally invasive proctectomy also matters. In the Colon Cancer Laparoscopic or Open Resection (COLOR) trial , “high-volume” hospitals that performed more than 10 laparoscopic proctectomy procedures per year had a lower conversion rate compared with “low-volume” hospitals that performed fewer than five cases per year (9% conversion vs. 24% conversion) . High-volume hospitals also had more lymph nodes recovered, fewer complications, shorter hospital stay, and shorter operative time independent of surgeon experience. What this means for the surgeon is that experience matters for both the individual and the institution.
As noted previously, there appears to be some evidence that robotics offers benefit over laparoscopy in obese male proctectomy patients in terms of decreased risk of conversion to open surgery . At least two articles have suggested the robotic learning curve for proctectomy has three phases and could be achieved within 25 cases [49, 50]. A direct comparison of the laparoscopic proctectomy learning curve vs. the robotic proctectomy learning curve is difficult to find. However, one study from South Korea noted that while tasks like splenic flexure mobilization and IMA dissection had similar learning curves between laparoscopic and robotic surgery, TME had a shorter learning curve when performed robotically . In this study, TME showed consistently shorter operative times for robotics after 22 cases. For the surgeon who is new to minimally invasive proctectomy, robotic surgery may prove to be easier to learn than a laparoscopic approach. The literature regarding transanal TME is developing, but currently it would seem prudent for this to only be performed by high-volume experts in proctectomy.
Tips and Tricks to Successful Minimally Invasive Colorectal Surgery in Obese Patients
Regarding minimally invasive proctectomy and colectomy in the obese patient, we have several recommendations for the surgeon:
Be clear with patients regarding your experience level. It is important to manage patients’ expectations regarding the duration of surgery and risk of conversion to open surgery. As you gain experience, the duration of surgery and risk of conversion will improve.