Splenic flexure mobilization

Introduction

Splenic flexure mobilization is an integral part of total mesorectal excision (TME) for rectal cancer and for segmental resection of splenic flexure, distal transverse colon, and proximal descending colon neoplasms. Splenic flexure mobilization may also be part of operations for sigmoid diverticulitis, ischemic colitis, Crohn’s disease, or any procedure that includes left hemicolectomy, subtotal colectomy, and total abdominal colectomy or total proctocolectomy for ulcerative colitis, Clostridioides difficile colitis, and other diseases that require splenic flexure mobilization.

Most surgeons will experience a complication due to splenic flexure mobilization over the course of their career. Understanding the principles of splenic flexure mobilization and how to avoid related complications is an important part of lifelong surgical training and requires detailed knowledge of anatomic relationships to the stomach, spleen, and pancreas, as well as arterial variations in the related mesocolon.

The robotic approach to splenic flexure mobilization offers several advantages related to enhanced vision and precise articulated instrument movements. This chapter is devoted to describing indications, key steps, and potential pitfalls related to splenic flexure mobilization using the robotic approach, though these principles apply to all operative approaches.

XI port placement

The strategy of robotic port placement is to maximize flex joints for lateral workspace and patient clearance buttons for vertical workspace. First, select the initial port incision 10 to 20 cm from the targeted workspace and insert the remaining ports 7 to 8 cm in a straight line perpendicular to the center of workspace anatomy. This arrangement allows 270 degrees of left and right lateral instrument reach with proper positioning of the robotic flex joints and maximum forward and underneath vertical workspace access with proper positioning of the patient clearance joints. The center of workspace anatomy is the target that enables maximal mobilization of the colon and allows resection of the neoplasm or other pathology. This targeted anatomy may not necessarily be the neoplasm or other pathology itself. The target anatomy center is different when the operation is for TME compared to segmental resection for splenic flexure neoplasia. For TME, the workspace includes the pelvis and the splenic flexure, and the center may be the distal descending or sigmoid colon ( Fig. 50.1 ). For segmental resection of splenic flexure neoplasia, the center of the workspace is the splenic flexure ( Fig. 50.2 ).

With experience, surgeons may develop variations in port placement, instruments, and instrument port location options that become individual preferences. A common option for TME is to use the tip up instrument for fixed retraction in R1, the fenestrated bipolar or cadiere instrument in R2, the camera in R3, and the hook or scissors, Vessel Sealer, and stapler in R4 (see Fig. 50.1 ). For segmental resection of the splenic flexure, some surgeons would prefer to have the instrument for fixed retraction in R4 rather than R1 in an arrangement that mirrors a common option for robotic right colectomy (see Fig. 50.2 ). Choosing the 0-degree or 30-degree robotic videoscope is based on surgeon’s preference, and both are reasonable choices. There may be some advantage to visualizing the top side of the splenic flexure with the 30-degree scope.

While Trendelenburg and right-side-down positioning are often chosen for sigmoid and low anterior resection, robotic Table Motion allows reverse Trendelenburg without detaching and reattaching robotic arms. Changing to the reverse Trendelenburg position allows small bowel loops to gravitate to the right lower quadrant for better visualization of the splenic flexure when the splenic flexure is not easily visualized in the Trendelenburg position. For an experienced surgeon without Table Motion, removing the robotic instruments under direct vision, detaching the robotic arms, placing the operating table in reverse Trendelenburg, reattaching robotic arms, and reinserting instruments adds only a few minutes to operating time. Another option for improving access to the splenic flexure during TME with the patient in Trendelenburg position is to rotate the flex joints of all four robotic arms so that the splenic flexure becomes the target anatomy. For segmental resection of splenic flexure neoplasia, reverse Trendelenburg with right side down is often the starting position and the only required position for splenic flexure mobilization.

Maximal mobilization of the splenic flexure requires several steps. The first step to splenic flexure mobilization depends on the operative indication. Splenic flexure mobilization during TME enables the descending colon to reach the pelvis for a tension-free colorectal anastomosis with good blood supply. Some surgeons mobilize the splenic flexure routinely for this operation and some are selective mobilizers, performing this part of the operation only when required for a tension-free anastomosis. ^, When routine, splenic flexure mobilization is often the first step in a TME operation. Segmental resection for splenic flexure neoplasia differs from operations for rectal cancer and diverticulitis with respect to how the arterial and venous colonic blood supply are preserved or resected with the specimen.

Splenic flexure mobilization for total mesorectal excision

The Xi da Vinci platform allows TME with complete splenic flexure mobilization without the need to redock the robot. The goal of splenic flexure mobilization is to move the splenic flexure closer to the pelvis for a tension-free descending colorectal anastomosis. This requires more than a simple lateral division of the line of Toldt to the splenic flexure. Splenic flexure mobilization for TME requires division of the inferior mesenteric artery (IMA) at or near the origin at the aorta or just distal to the origin of the left colic artery depending on the surgeon’s preference. Some surgeons believe that complete lymph node resection and maximal reach of the descending colon to the pelvis require division of the IMA at or near the origin from the aorta. Others prefer dissection of lymph nodes at the IMA origin with division of the IMA just distal to the origin of the left colic artery in a way that allows en bloc resection of all lymph nodes with the specimen. Some surgeons prefer division of the IMA after medial mobilization of the descending colon and sigmoid mesentery from the retroperitoneum (to protect the ureter) and leave the inferior mesenteric vein (IMV) intact, while others prefer division of the IMV in addition to the IMA. For those who divide both artery and vein, many start with medial to lateral dissection under the IMV, thereby beginning the splenic flexure mobilization process at that location.