Cannula Positioning

The cannulae are placed as shown in Figure 8.7.2. Technique

Phase I: Transection of the Inferior Mesenteric Artery and Vein, Medial Dissection of the Left Mesocolon, Pelvic Dissection, Left Lateral Mobilization of the Sigmoid Colon, and Transection of the Upper Rectum

The procedure begins as in proctosigmoidectomy. The patient is placed in a steep Trendelenburg position and is tilted right side down so the small intestine falls into the right upper quadrant. All small intestinal loops are retracted out of the pelvis using bowel graspers. The assistant holds the mesosigmoid close to the inferior mesenteric artery (IMA) bundle under traction in a ventrolateral direction using a bowel grasper in the left-lower-quadrant cannula and a bowel grasper in the left-upper-quadrant cannula to lift up the bowel edge close to the rectosig-moid junction. The peritoneum is incised immediately to the right of the IMA, starting at the sacral promontory (Figure 8.7.3). Under continuous traction, the peritoneum is incised cephalad toward the direction of the origin of the IMA and caudally toward the right lateral rectal

Figure 8.7.2. Positions of the cannulae for the laparoscopic total abdominal colectomy.

Laparoscopic Transverse Colectomy

Figure 8.7.2. Positions of the cannulae for the laparoscopic total abdominal colectomy.

Small Intestine Mesenteric Dissection

Figure 8.7.3. Dissection is commenced at the sacral promontory posterior to the inferior mesenteric vessels.

stalks. Using blunt dissection, the inferior mesenteric artery and vein are swept ventrally away from the preaortic hypogastric neural plexus, which is swept dorsally to prevent injury to it. Dissection is continued medially beneath the inferior mesenteric artery and vein; the left ureter and the gonadal vessels are identified and are swept posteriorly (Figure 8.7.4). If the ureter cannot be readily and easily identified at this point in the dissection, the lateral attachments of the sigmoid are incised, the sigmoid colon is mobilized left to right, and the gonadal vessels and the left ureter then are identified and dissected free of the mesentery.

Once the origin of the IMA is identified, the peritoneum is incised anteriorly over this pedicle and then left toward the inferior mesenteric vein. Using a combination of blunt and sharp dissecting techniques, a peritoneal window is made just lateral to the inferior mesenteric vein. The pedicle of the inferior mesenteric artery and eventually vein (if anatomically close) is ligated above or below the left colic artery (according to the surgeon's judgment) with a 30-mm endoscopic vascular stapler, but only after the left ureter has been clearly identified and retracted so it is not injured (Figure 8.7.5). We prefer to leave the IMA 1.0-1.5 cm long so if any bleeding occurs, an additional ligature can be applied to the vessel. After the stapler has been placed across the IMA (and concurrently placed across the inferior mesenteric vein if this is feasible and safe), the stapler is closed and again the ureter is checked. The tip of the stapler should be free and clearly visible, and then fired. Before the fired stapler is opened, both ends of the pedicle are grasped by surgeon and assistant so any bleeding can be easily

Inferior Hypogastric Plexus
Figure 8.7.4. Dissection is continued superiorly beneath the IMA, protecting the hypogastric neural plexus.
Ligation Superior Rectal Pedicle
Figure 8.7.5. After creating a peritoneal window to the left of the inferior mesenteric vein, the pedicle is ligated using an endoscopic stapler. Note that the ureter is clearly isolated posterior to the pedicle.

controlled. If the inferior mesenteric vein is not simultaneously ligated by the first stapler, it is clipped or stapled separately. Next, the left colic artery must be ligated along with its accompanying vein (Figure 8.7.6). After this, the left mesocolon is dissected free posteriorly using a blunt instrument such as the endoscopic paddle, sweeping Gerota's fascia away from the posterior surface of the colonic mesentery until close to the splenic flexure and below the descending and left transverse colon (Figure 8.7.7). In thin patients, the spleen may become visible below the colonic flexure. Then, the left-lateral attachments of the upper rectum and sigmoid colon are dissected free, and the sigmoid colon is completely mobilized using sharp and blunt dissection as in open surgery. Again, great care should be taken at this juncture to identify and to avoid any injury to the gonadal vessels or the ureter. The upper rectum is mobilized. To identify the distal resection line of the bowel exactly, an experienced assistant may perform proctoscopy. At the specified point of resection (12-15 cm from the anal verge), otherwise just below the level of the promontory, the mesorectum is divided sharply, starting on the right side; the superior hemorrhoidal artery which is encountered during division is coagulated using the harmonic scalpel or may be clipped (Figure 8.7.8). If the mesorectum is difficult to dissect or if several prominent vessels must be divided, it may be most expeditious to divide the mesorectum with a 30-mm endoscopic stapler, after dissecting a plane between the posterior wall of the rectum and the anterior portions of the mesorectum. The rectum itself is then transected with one or two applications of the Endo GIA stapler (Figure 8.7.9).

Left Colic Artery
Figure 8.7.6. The left colic artery and vein are ligated separately.
Laparoscopic Staplers
Figure 8.7.7. The left mesocolon is dissected away from the retroperitoneal structures using medial to lateral blunt dissection.
Harmonic Scalpel Device
Figure 8.7.8. The mesorectum is divided sharply, starting on the right side, using a harmonic scalpel or bipolar device.
Laparoscopic Scalpel
Figure 8.7.9. The rectum is next divided from the right side using one or two applications of an endoscopic stapler.

Phase II: Mobilization of the Left Colon and the Splenic Flexure, Dissection of the Omentum

As soon as the rectosigmoid junction is divided, the surgical team repositions itself for the second phase of the operation, splenic flexure and left colon mobilization. The surgeon works through the suprapubic and the left-lower-quadrant cannulae, whereas the first assistant works through the right-upper-quadrant and the right-lower-quadrant cannulae.

First, the colon is pulled laterally by the assistant or the surgeon. All medial mesenteric attachments should be divided as far cephalad as possible, in a line parallel to and just to the left of the inferior mesen-teric vein. Occasionally, there is a left colon or a splenic flexure venous branch that must be isolated and divided during this process. As the posterior surface of the left mesocolon has already been dissected ceph-alad as far as possible, the colon is now pulled medially and caudally by the assistant using a Babcock and a bowel grasper. This way, the lateral attachments of the left colon are placed under tension and may be divided by the surgeon more easily. This process moves proximally up the colon as the dissection proceeds cephalad. This sequence of retraction and dissection will greatly expedite the splenic flexure takedown (Figure 8.7.10). During this dissection, the surgeon must remain in the proper planes - generally close to the bowel edge laterally, and between Gerota's fascia and the colonic mesentery (Toldt's fascia overlying the Gerota's fascia is swept posteriorly with it).

Splenic Flexure
Figure 8.7.10. The colon is reflected medially and dissection of the lateral attachments of the left colon proceed up to the splenic flexure.

In the region of the splenic flexure, the greater omentum gradually appears and is distinguishable from the epiploic appendices by its finer lobulated fatty texture. Separation of the omentum from the colon and these appendices is essential for accurate mobilization of the flexure (Figure 8.7.11). The surgeon may need to switch cannula positions to comfortably reach the splenic flexure, moving from the suprapubic and the left-lower-quadrant cannulae to the left-upper-quadrant and the left-lower-quadrant cannulae.

If the splenic flexure proves difficult to dissect, the dissection can be continued right to left from the distal transverse colon toward the splenic flexure, detaching the omentum from this area as in conventional surgery and gaining entry into the lesser sac (Figure 8.7.12). In our experience, it is important to mobilize the left colon and the left mesocolon as far cephalad as possible in the dorsal mesenteric plane adjacent to Gerota's fascia. This greatly simplifies the mobilization of the splenic flexure, and may simplify dissection of the greater omentum and the lateral adhesions close to the colonic wall. With complete mobilization of the splenic flexure, the surgical team dissects the omentum from the distal transverse colon as far to the right as is possible and practical. This ends the second phase.

Phase III: Transection of the Ileocolic and Middle Colic Vessels, Medial and Lateral Mobilization of the Right Colon and the Hepatic Flexure

At this point, the surgical team repositions itself for the third phase of the procedure, the mobilization of the terminal ileum, right colon, and

Mobilize Colon
Figure 8.7.11. Separation of the omentum from the colon is required for accurate mobilization of the splenic flexure.
Mobilizatiojn The Splenic Flexure
Figure 8.7.12. Splenic flexure mobilization may be expedited with the dissection proceeding from medial to lateral on the transverse colon.

right transverse colon. The patient is tilted left side down and in the Trendelenburg position so the small intestine falls toward the left upper quadrant. The first assistant places the mesentery of ileum and colon laterally close to the ileocecal junction under tension with graspers in the left-upper-quadrant and the left-lower-quadrant cannula sites. Thus, the ileocolic vascular pedicle may be identified more easily. The surgeon begins dissection through the suprapubic and the right-lower-quadrant cannulae, incising the peritoneum below the ileocolic vascular bundle (Figure 8.7.13). This incision is enlarged toward both sides. The ileocolic artery and vein are identified on their dorsal aspects in the front area of the mesentery and are traced to their origin from the superior mesenteric artery and vein. All vessels are carefully dissected at a safe distance from the superior mesenteric artery and vein, and a window through the mesentery is made on either side of the two vessels. The ileocolic pedicle is traced distally to the cecum before division to correctly distinguish it from the superior mesenteric artery and vein. This requires examining the vessels from their ventral aspect also. The pedicles are clipped and then divided, or stapled and transected with an endoscopic vascular stapler or coagulated using a bipolar device (Figure 8.7.14). Again, both ends of the vessels are grasped by surgeon and assistant to be able to control any unexpected bleeding.

Now the ileal and right colonic mesentery are completely freed retroperitoneally by bluntly dissecting a tunnel beginning dorsal to

Bleeding Control Deviced

Figure 8.7.13. Phase III begins with incision just below the ileocolic pedicle.

Figure 8.7.13. Phase III begins with incision just below the ileocolic pedicle.

Laparoscopic Surgery Device Image
Figure 8.7.14. After mobilizing the pedicle, it is ligated well away from its origin using a bipolar coagulation device.

the ileal mesentery. For this maneuver, the endoscopic paddle is a very useful instrument. The duodenum, the right ureter, the gonadal vessels, and Gerota's fascia become clearly visible. All these anatomic structures are swept down carefully to avoid any injury to them (Figure 8.7.15).

Dissection of the right mesocolon is continued cephalad from the ventral aspect of the right mesenteric root, continuing superiorly and medially until the peritoneal reflection of the right branch or the trunk of the middle colic vessels is seen (Figure 8.7.16). This reflection is divided sharply and blunt dissection is used to isolate the roots of the middle colic vessels. The middle colic vessels are next separated from the retroperitoneal structures and the structures of the lesser omental sac; particular care is needed near the superior aspect of these vessels. Depending on the individual anatomic situation and other factors such as obesity, the middle colic vessels may be separated further centrally close to their roots or further distally in the area of their branches. After circumferential dissection (Figure 8.7.17), the vessels are either coagulated using a bipolar device or ligated with large clips and cut or separated by applying a 30-mm endoscopic vascular stapler. Just to the left of the middle colic pedicle, the mesenteric edge of the transverse colon is grasped, and the peritoneum is incised as far to the left as possible until the region of previous left colonic dissection (phase II of the operation) is reached and connected. Additional vessels of the transverse mesocolon are divided as needed. At this point, the remaining greater

Ileal Mesentery
Figure 8.7.15. The ileal and right colonic mesenteric attachments are completely freed retroperitoneally, bluntly dissecting a tunnel dorsal to the ileal mesentery.
Toldt Fascia
Figure 8.7.16. Just cephalad to the ligated ileocolic pedicle, the middle colic pedicle is identified.
Ileocolic Pedicle
Figure 8.7.17. The ligation of the middle colic vessels may be safer if performed on the right and left branches, rather than on the main trunk.

omental attachments to the right transverse colon are dissected from the colon, thus completely freeing the omentum from the bowel. Vessels of the omentum are sealed using electrocautery, the harmonic scalpel or clipped and divided as necessary.

The terminal ileum is next grasped and the proximal resection line is identified near the ileocecal junction. The mesentery of the terminal ileum and the ileum itself may be divided either laparoscopically inside (e.g., in case of malignancy) or after extraction of the bowel outside of the abdominal cavity which in many cases is faster and does not require a longer incision line. In the rare case of laparoscopic division, the ileal mesentery is completely dissected starting from the left side of the ileocolic pedicle. All mesenteric vessels are clipped, and divided or coagulated. The ileum may be transected using a 45-mm endoscopic stapler.

In the next step, complete mobilization of ileum and right colon is accomplished. The assistant is carefully pulling the terminal ileum and the cecum cephalad and medially. The attachments of the ileum just medial to the base of the appendix are incised, carrying the incision cephalad toward the root of the mesentery and to the inferior edge of the duodenum (Figure 8.7.18). Next, starting at the cecum next to the

Laparoscopic Appendix Harmonic Scalpel

root of the appendix, the right colon and the hepatic flexure are completely detached from remaining retroperitoneal structures. The patient's Trendelenburg position should be reversed as the hepatic flexure is reached. Because most of the mobilization of the colon has been performed dorsally, only minor adhesions with the lateral and posterior abdominal wall have to be transected up to and just beyond the hepatic flexure. Then, the last lateral adhesions of the right transverse meso-colon have to be dissected (Figure 8.7.19). Finally, the remaining attachments of the omentum to the proximal transverse colon, then the hepatocolic ligament, are divided (Figure 8.7.20). At this point, the colon should be completely free from surrounding structures. This is checked by running the colon at its entire length from the distal sigmoid orally toward the cecum using Babcock and bowel graspers. At the same time, the colon is moved on top of the small bowel loops to make extraction easily possible. To start this maneuver, especially in obese patients, it may be necessary to tilt the patient left side up again.

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Responses

  • Moshe Thomas
    Why position with right side down mesenteric vessels?
    7 years ago

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