3.42 ). When performing a

laparoscopic hand-assist approach, placing the thumb on the sacral promontory and pinching the mesentery of the left colon between the thumb and the index fi nger will aid in isolating the IMA pedicle and help initiate one’s medial-to­lateral dissection (Fig. 3.43 ).

3.28 and 3.44 ). In cases where the ureter is not easily

Once the ureter has been identifi ed, the inferior mesenteric artery is often ligated and transected to facilitate the pelvic dissection. The medial-to-lateral mobilization is performed similar to that done on the right side. The retroperitoneal refl ection is gently swept posterolaterally away from the colon and mesentery. The dissection proceeds cephalad to the level of the superior pole of the kidney. At this point, the IMV may be identifi ed and mobilization of the splenic fl exure may be performed (Figs.

3.6 and 3.45 ).

The authors perform a proximal ligation of the IMV in almost all anterior or low anterior resections to aid in appro­priate mobilization for tension-free colorectal or coloanal anastomoses. With the distal splenic fl exure and proximal descending colon and mesentery retracted anteriorly, the infe­rior mesenteric vein (IMV) can be identifi ed with avascular areas surrounding the vessel (Figs. 3.6 and 3.46 ). Often, the fourth part of the duodenum or proximal jejunum will have some attachments to the descending colon mesentery in this area that will need to be divided fi rst. The IMV transection is performed just caudal to the pancreas and ligament of Treitz and prior to its origin of insertion into the splenic vein (Figs. 3.47 and 3.48 ). Ligation can generally be performed with an energy source such as ultrasonic shears or bipolar- type vessel sealing devices. Once this is performed, the mesentery of the splenic fl exure can then be grasped superiorly and anteriorly, and the retroperitoneal refl ection line of Toldt can then be gently swept posteriorly if not yet completed during the medial-to-lateral mobilization. This proceeds proximally and superiorly as high as possible toward the spleen. Careful technique should be used in IMV division as the vessel can easily be sheared and retract if excess tension or inappropriate ligation is performed.

ligament. Congenital fusion attachments of the posterior leaf of the omentum to the mesocolon may need to be divided upon entry into the lesser sac. Similar attachments of the colonic mesentery to the stomach lead to inadvertent gastric injury. Dissection proceeds separating the attach­ments of the splenic fl exure and its mesentery away from the spleen. At this point, an avascular plane is generally noted and dissection can safely proceed bluntly. The splenic fl exure will then be held in place by thin mesenteric attach­ments that can be divided.

In some situations, the lesser sac may be dense with adhesions, and care must be taken not to proceed too poste­riorly and into the pancreatic parenchyma. If the adhesions make dissection diffi cult, another approach to the splenic fl exure may be afforded by an inferior-to-superior approach, starting at the ligament of Treitz. With the distal transverse colon mesentery retracted anteriorly, there is generally an avascular plane identifi ed near and just above the ligament of Treitz along the transverse mesentery and above the duo­denum. Entry into this window will lead into the lesser sac above the pancreas and behind the stomach (Figs. 3.51 ,

When performing a pelvic dissection, the surgeon often ini­tiates the dissection of the rectum posteriorly. The dissection plane is developed immediately posterior to the fascia propria of the rectum. This fascia is an extension of the pelvic fascia envel­oping the rectum, fat, nerves, and blood and lymphatic vessels. There is a loose alveolar plane between this and the presacral fascia (Fig. 3.23 ). The dissection is carried down sharply to the levator ani and puborectalis sling posteriorly and laterally, taking care to avoid the pelvic nerves along the sidewalls whenever possible (Fig. 3.54 ).

3.56 ).

The facial plane is then continued along the lateral aspects of the extraperitoneal rectum. The lateral ligaments or stalks are considered condensations of the pelvic fascia. They are

After developing the posterior and lateral planes, the anterior dissection is then performed. Continuation of the lateral and posterior dissection can often lead the surgeon in the right plane. Commonly, there is an “open C”-type or “opening- zipper” confi guration of this fascia at this level that will demarcate the appropriate dissection plane (Fig. 3.26 ). In this instance, starting from a known to unknown dissec­tion will help identify the appropriate dissection plane with loose alveolar tissue as the defi nitive marker. Here, too, there will be a loose alveolar space denoting the appropri­ate plane. The vagina, or prostate and seminal vesicles, will be visualized anteriorly as dissection proceeds caudally (Figs. 3.24 and 3.57 ).