Robotic Pelvic, Paraaortic, and Infrarenal Lymphadenectomies
Marie-Hélène Auclair
Robert Holloway
GENERAL PRINCIPLES
Definition
Pelvic and paraaortic lymphadenectomy represents a major component for the staging of gynecologic malignancies. When it was first described as a part of staging for endometrial cancer, it was “sampling” of pelvic and paraaortic nodes.
Today the borders for systematic pelvic lymphadenectomy include (a) mid-common iliac (CI) artery superiorly; (b) deep circumflex iliac vein inferiorly; (c) mid-psoas muscle laterally; (d) ureter medially; and (e) obturator nerve and obturator fossa dorsally.
The paraaortic node dissection boundaries are Right side: (a) right ovarian vein entry into the vena cava; (b) mid-CI artery inferiorly; (c) right ureter laterally; and (d) aorta medially. Left side: (a) level of the entry of the left ovarian vein into the left renal vein superiorly; (b) mid-CI artery inferiorly; (c) left ureter laterally; and (d) the aorta medially.
It is now recognized that the infrarenal lymph nodes are important for complete staging of women with high-grade histologies, positive pelvic nodes, or deep invasion of large uterine tumors.
This chapter will discuss pelvic and paraaortic node dissection (video and text courtesy of Dr. Marie-Hélène Auclair) and infrarenal node dissection (video and text courtesy of Dr. Robert Holloway).
Anatomic Considerations for Infrarenal Node Dissection
The left renal vein crosses the anterior surface of the aorta in approximately 95% of patients, and inferior to the aorta in 5%, inserting into the vena cava approximately 4 to 5 cm cephalad to the inferior mesenteric artery (IMA). The IMA is usually 3 to 6 cm above the aortic bifurcation. The left gonadal vein courses parallel and just medial to the ureter, draining into the left renal vein. The right gonadal vein also closely parallels the ureter and drains into the vena cava laterally above the IMA and just inferior to the left renal vein. The right renal vein is usually not exposed during this dissection, entering the vena cava inferior and laterally on the vena cava, at or above the level of the left renal vein. The third part of the duodenum must be reflected cephalad in order to expose the renal veins (Fig. 14.1).
IMAGING AND OTHER DIAGNOSTICS
It is advisable to perform contrasted CT imaging of the abdomen and pelvis preoperatively for patients with high-grade histologies (grade 3 endometrioid, papillary serous, mixed Mullerian sarcoma, clear cell, etc.). Enlargement of infrarenal lymph nodes should alert the surgeon to the necessity of completing the dissection if the knowledge gained will influence the decisions about adjuvant therapy. In addition, the discovery of stage IV disease may influence the decisions about route of surgery, goals of surgery, and potentially the use of neoadjuvant chemotherapy.
PREOPERATIVE PLANNING
Complete surgical staging may not be appropriate for all patients (e.g., patients with grade 1 endometrial cancer or stage IIB or other cervical cancer) and new modalities such as sentinel lymph node dissection may be helpful for select patients.
In order to provide informed consent, the surgeon should anticipate which patients will likely benefit from complete lymphadenectomy, as this can be associated with morbidity. Not all patients are suitable candidates for a complete infrarenal aortic lymphadenectomy. Short stature (<155 cm), coupled with morbid obesity (BMI >40 kg/m2) and large amounts of mesenteric adipose tissue that is more common in patients with diabetes, can render this surgery quite difficult because of compromised exposure related to inability to displace small bowel.
When contemplating infrarenal aortic lymphadenectomy, the indications for surgery and anticipated alternative plans, in the event that access to the infrarenal space is compromised, should be discussed with the patient and the operative team. For patients with lymphadenopathy at the infrarenal vein and no other evidence of upper abdominal metastasis, removal of bulk disease to improve control may be the goal. Possible conversion to laparotomy may be required if the anatomy is difficult secondary to obesity. In patients with normal-appearing lymph nodes, however, many surgeons do not think conversion to laparotomy provides enough information from the perspective of designing adjuvant therapy to warrant the additional morbidity associated with laparotomy, especially as combination chemotherapy is now frequently administered in high-risk disease. Decisions about the extent of the radiation fields are best determined by the status of pelvic and infrarenal lymph nodes and alternatively by the radiographic appearances of the nodes, with the knowledge of pelvic node status when the infrarenal dissection is not completed. The risk of infrarenal metastasis is approximately 17% when pelvic nodes are positive and the lower inframesenteric aortic lymph nodes are negative.
To ensure proper exposure, it may be beneficial to do a bowel preparation to collapse the bowel. This can usually be accomplished with a clear-fluid diet the day prior to the procedure, with the addition of a fleet enema.
SURGICAL MANAGEMENT
Selection of patients that benefit from complete pelvic and paraaortic lymphadenectomy is being evaluated, following two highly publicized randomized trials that have failed to show any improvement in overall survival.
The role of sentinel lymph node dissection for replacement of full pelvic and paraaortic lymphadenectomy is currently
being explored in endometrial and cervical cancer, to provide staging information while avoiding the morbidity associated with full lymphadenectomy (see Chapter 13, Robotic Sentinel Lymph Node Dissection).
Figure 14.1. Anatomy of the vessels, nodes, and nerves in the pelvic and paraaortic retroperitoneal space.
The infra-renal aortic lymphadenectomy procedure performed with robotic-assisted laparoscopy shares several key aspects of traditional laparoscopy, although the viewpoint from the camera is opposite that of laparoscopy with a view from the upper abdomen looking caudally, not from the pelvis looking cephalad, as in most laparoscopic procedures.
Positioning
Position the patient supine in a modified dorsal lithotomy position with legs in Allen stirrups. The patient should be secured to the table on gel pads or some similar system to prevent sliding while in Trendelenburg position. Padded shoulder stops are recommended for morbidly obese patients. Avoid restraining the arms to the table as any slippage may cause stretch on the brachial plexus and pad the neck and head in a neutral position. After placing ports, dock the da Vinci unit with the patient in steep (30 to 34 degrees) Trendelenburg position.
The legs are placed within adjustable stirrups to allow for repositioning of the legs during the procedure, and our standard is to place pneumatic compression stockings for DVT prophylaxis.
Adequate foam or gel padding around the arms and face is used for patient protection.
Approach
The robotic platform is usually center-docked using the Si model (Fig. 14.2) and side-docked using the Xi model with the boom oriented toward the pelvis, with the patient in Trendelenburg position (Fig. 14.3).
The port placement for the Xi is shown in the figure (Fig. 14.4). The camera port is placed above the umbilicus 23 to 27 cm above the symphysis pubis. Two laparoscopic assist ports are placed for optimal bedside assistance with this procedure and we prefer the third operative arm placed on the left at the level of the camera, while arms 1 and 2 are angled 10 degrees below the camera port (Fig. 14.3).
The da Vinci Xi model has more range and can be more forgiving, whereas placement with the Si must be more strategic, making sure the camera port is high enough to visualize the infrarenal spaces.
Prior to docking the robot, the patient is placed into steep Trendelenburg position (35%) to assist with bowel mobilization into the upper abdomen. For pelvic and paraaortic lymphadenectomy, the Si model robot is placed between
the legs, facing the perineum and allowing to reach the high paraaortic area without conflicts between the arms. The Xi model robot can also be docked in the side position at approximately a 45-degree angle to the lower torso aligned with the border of the leg stirrup either on the left or right side depending on surgeon preference, to allow access to the vagina for gynecologic surgery. This side docking will allow good access to the pelvis and inframesenteric artery area but will often cause problems to reach the infrarenal nodes. However, if there is incomplete exposure for the completion of a paraaortic lymphadenectomy, the robot can also be undocked and reversed, with the column adjacent to the patient’s shoulder or head.
Figure 14.2. Side-docking position of the da Vinci Si robot at the patient’s bedside during surgery with a 35% Trendelenburg position.
Figure 14.3. Side-docking position of the da Vinci Xi robot for the high paraaortic node dissection.
Figure 14.4. Port placement for Infrarenal Node Dissection for da Vinci Xi robot.
The placement of the trocars, robot, and robotic arms that are suggested are for the da Vinci Si model (Fig. 14.5).
Prepare the operative field prior to docking by laparoscopically displacing the omentum in the left upper quadrant, preferably under the left ribcage. This pulls the transverse colon into the upper abdomen allowing more room to displace small bowel. A Ray-Tec gauze is placed at the ligament of Treitz to retard small bowel intrusion into the field and is available for blotting when necessary.
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