eMedicine Specialties > Urology > Surgery

Laparoscopic Pelvic Lymph Node Dissection: Treatment

Author: Jay T Bishoff, MD, Director, Section of Endourology, Department of Urology, Urology San Antonio
Coauthor(s): William J Harmon, MD, Director of Minimally Invasive Urologic Surgery, Urology San Antonio, PA, Associate Clinical Professor, Division of Urology, UTHSC, San Antonio, TX; Robert G Moore, MD, Director of Endourology and Minimally Invasive Surgery, Director of Endourology Fellowship, Associate Professor, Department of Surgery, Division of Urology, Saint Louis University
Contributor Information and Disclosures

Updated: Jan 29, 2007

Treatment

Preoperative Details

Some surgeons do not use bowel preparation for laparoscopic surgery. Other surgeons favor bowel preparations prior to surgery. For those who favor bowel preparation, one regimen is explained here. Patients are started on clear liquids the afternoon prior to the procedure, and 2 enemas are administered the evening prior to surgery. Enemas decompress the colon, facilitating the lymph node dissection. Should a difficult dissection be anticipated based on patient history, full mechanical and antibiotic bowel preparation may be performed the day before surgery. Broad-spectrum antibiotics are administered parenterally 1 hour prior to surgery.

Patient positioning and/or setup

After the induction of general anesthesia, an orogastric tube is placed and pneumatic compression stockings applied to the lower extremities. All pressure points are padded, including the patient's heels and arms. The arms are tucked at the patient's side and secured. The chest and pelvis are secured with strips of 3-inch tape, and a mid-thigh safety strap is used. A sterile scrub is performed from the xiphoid process to the pubis and from the right to the left anterior axillary lines. The penis and scrotum are prepped and draped into the sterile field. A bladder catheter is placed to decompress the bladder, decreasing the chance of injury during trocar placement. If pneumoscrotum is a concern, a sterile gauze roller bandage is wrapped around the penis, scrotum, and catheter to prevent carbon dioxide accumulation in the penis and scrotum, although this is an uncommon occurrence.

The patient is placed in the supine position, and the operating room table is moved to approximately 10° in the Trendelenburg position for initial Veress needle placement and insufflation. After pneumoperitoneum is established, the patient can be placed in the extreme Trendelenburg position, allowing the intestines to vacate the pelvis.

The operating surgeon stands on the contralateral side of the node dissection, with the first assistant positioned on the ipsilateral side. A video screen placed at the foot of the table allows visualization of both sides of the procedure by all members of the surgical team.

Intraoperative Details

Insufflation

A Veress needle is introduced into the abdominal cavity through the base of the umbilicus. This site is chosen for initial insufflation because all fascial layers fuse into one single layer. A relatively low-flow, low-pressure carbon dioxide state (<8 mm Hg, <1 L/min) is used until the entire abdominal wall is elevated, indicating proper placement of the Veress needle. Additional ports are placed at a pressure of 20 mm Hg, and pressure is then decreased to 15 mm Hg during the node dissection.

Many different approaches are used to gain access to the abdomen. Veress needle access, the open technique, the Hasson technique, or modified open techniques are all viable options. Once the initial trocar is placed and the underlying tissue is inspected for injury, the secondary ports are placed under direct vision.

For patients with a history of extensive or multiple abdominal surgical procedures or history of peritonitis, the Hasson technique may be useful for initial port placement. The Hasson system consists of a trumpet valve with tying struts, a cone-shaped sleeve, and a blunt-tipped obturator. A 2- to 3-cm incision is made in the skin at the insertion site, the preperitoneal fat is swept off the fascia, and the fascia is incised. The peritoneum is elevated and opened with a pair of forceps and opened sharply. Entry into the peritoneum is confirmed, and the trocar is inserted and secured. The pneumoperitoneum is established through the Hasson trocar, and the abdomen is inspected with the laparoscope.

Trocar placement

Two variations of trocar placement are used commonly. The diamond configuration uses two 10-mm ports, 1 at the umbilicus and 1 approximately 4-6 cm above the symphysis pubis in the mid line. Two 5-mm ports are placed near the McBurney point in the midclavicular line on both sides.

If the patient is obese, the fan configuration may be more appropriate. In the fan position, 5 trocars are used. A 10-mm trocar is placed at the umbilicus for the laparoscope. A second 10-mm trocar is placed on the left side, and a 5-mm trocar is placed on the right side at the level of the umbilicus, lateral to the inferior epigastric vessels, in line with the anterior superior iliac crest. Two additional 5-mm trocars are placed laterally, midway between the umbilicus and the pubis symphysis (see Image 2).

Pelvic anatomy inspection

A 0° laparoscope is used for trocar placement and inspection of the abdomen. The node dissection is performed with a 30° laparoscope. Start the dissection on the side with the highest likelihood for malignant lymph node involvement. Adhesions are divided sharply to expose the pelvic structures.

The patient is rotated approximately 30° towards the surgeon, elevating the side of initial dissection, and the operating room table is placed in a 25-30° Trendelenburg position, allowing the bowel to fall away from the side of lymphadenectomy. The medial umbilical ligament, iliac vessels, internal inguinal ring, vas deferens, and cord structures are identified. The line of peritoneal incision is then determined. With the scrotum prepared into the surgical field, the surgeon can apply traction to the testicle on the side of dissection to identify the spermatic cord structures as they enter the internal inguinal ring (see Image 2).

Exposure of external iliac artery and vein

Using electrocautery through the laparoscopic scissors and a curved grasper for counter traction, an incision is made just lateral to the medial umbilical ligament, from the pubic bone to the common iliac artery. Dissection of the peritoneum off underlying structures then is accomplished to expose the vas deferens, which is isolated, clipped, and divided between surgical clips. All lymphatic tissue is divided with either electrocautery or ultrasonic energy to prevent lymphocele formation. Placing the point of both laparoscopic instruments in the loose areolar tissue just beneath the incised vas and moving the instruments in opposite directions (one cranially and the other caudally) exposes the underlying external iliac artery and vein. Not only does the above operative maneuver expose the external iliac vessels, it also moves the ureter cranially, away from the dissection, thus decreasing the likelihood of injury.

The boundaries of the dissection are identical to the open procedure, inferiorly the circumflex iliac artery, superiorly the internal iliac artery, laterally the external iliac vein, and medially the obturator nerve. The lateral dissection starts with identification of the external iliac vein, which is identified by looking for pulsation from the external iliac artery. The fatty tissue inferior to the arterial pulsation is elevated, and, using gentle blunt dissection in a cephalocaudal direction, with the tip of the irrigator/aspirator, the vein is exposed (see Image 3).

The loose connective and lymphatic tissue is elevated off the vein and dissected free from the level of the bifurcation of the common iliac vein to the pubic bone and medially until the obturator internus muscle is observed. At the pubic bone, an accessory obturator vein often is encountered. The dissection should terminate proximal to the branch of the obturator vein to minimize the risk of troublesome bleeding.

The lymphatic tissue usually can be dissected off the pelvic sidewall with a combination of blunt and sharp dissection. The surgical assistant can medially elevate the nodal packet to facilitate dissection from the pelvic wall. Accessory blood vessels and lymphatic channels should be clipped and divided.

Once the lateral portion of the dissection is complete, attention is directed to the portion of the lymph node packet near the medial umbilical ligament and decompressed bladder wall. The assistant retracts the nodal packet laterally to allow development of the plane between the medial umbilical ligament and nodal tissue using blunt dissection. After defining and isolating the medial and lateral borders, the apex of the nodal packet near the pubic bone is clipped and divided. Cephalad retraction of the distal portion of the nodal package then provides a clear view of the obturator nerve.

The remainder of the dissection involves cephalad retraction of the nodal package and blunt dissection of the remaining deep portion away from the pelvic sidewall. Keeping the obturator nerve in clear view is important to avoid injury. The superior aspect of the nodal packet is thinned, clipped, and divided (see Image 4).

Tissue extraction

The nodal tissue is removed through a 10/12-mm port. To prevent loss of the specimen, all specimens are removed in an impermeable sac (see Image 5).

The specimen is passed off the field for immediate frozen section if prostatectomy or other treatment is planned under the same anesthetic. While frozen section evaluation of lymph nodes has acceptable sensitivity and specificity, the false-negative rate ranges from 15-19%. This is an important consideration for those undergoing additional surgery. After completion of the most suspicious side, the contralateral dissection is undertaken with the same technique.

Closure

At the end of the procedure, the intra-abdominal pressure is decreased to 5 mm Hg and the obturator fossa on both sides is inspected carefully for adequate hemostasis. A complete evaluation of the pelvic structures is performed to determine the presence of injury to pelvic viscera or vessels. The fascia of 10-mm trocar sites is closed under direct vision.

Extended laparoscopic dissection

Bladder, urethral, and penile cancers often require an extended nodal dissection. Unlike the standard or modified pelvic node dissection that removes the obturator and hypogastric nodes only, the extended dissection also incorporates the common and external iliac nodes.

In the extended dissection, the peritoneal incision extends from the pubis (starting lateral to the medial umbilical ligament) and continues cranially along the line of Toldt. The vas deferens is observed over the medial umbilical ligament as it enters the internal inguinal ring. After the vas deferens has been divided, the medial umbilical ligament is traced back to the internal iliac artery and the ureter is identified as it crosses the common iliac vessels.

The lateral border of the dissection is developed from the pubis and the circumflex iliac vein to the level of the common iliac artery and medial to the genitofemoral nerve and external and internal iliac vessels. The dissection proceeds along the anterior border of the common iliac artery. The cephalad extent of the packet is secured with hemoclips and is rolled away from the iliac artery. The genitofemoral nerve is identified as the lateral dissection continues. Any psoas branches from the common iliac artery are clipped and divided. The common iliac and external iliac arteries are displaced medially, exposing the bifurcation of the common iliac artery and nodal tissue. The obturator nerve is observed passing below this bifurcation. The external iliac vein now is identified, and lymphatic tissue is cleared from the pubis to the bifurcation of the common iliac vessels.

The medial border of dissection starts with the ureter at the common iliac artery and continues along the lateral border of the medial umbilical ligament and bladder to the pubis. The lymphatic tissue is pulled from the sidewall using traction and suction from the irrigator aspirator. Large lymphatic channels are clipped and divided. The caudal limit of the extended dissection is the pubic bone. Care must be taken to not injure the superficial epigastric vein running medially and superiorly into the femoral vein.

Posteriorly, the border of dissection is the obturator nerve and internal iliac vessels. Using the irrigator aspirator tip, the lymph node packet is dissected gently from the pubic ramus, and the obturator nerve is identified. Suction and dissection is applied parallel to the nerve to prevent avulsion injury. The obturator artery and vein usually are found medial to the nerve. Clipping and dividing the obturator vessels usually is not necessary. The packet is dissected along the obturator nerve until the nerve passes posterior to the iliac vein, where the lateral dissection was performed. Multiple small vessels and lymphatic channels are in the packet under the obturator nerve, which can be clipped and divided. Application of electrocautery in this area results in powerful adduction of the thigh and may lead to inadvertent vascular injury.

The cephalad margin is the common iliac artery. The branching of the common iliac artery and vein is observed in the lateral dissection. The node dissection continues along the medial surface of the internal iliac artery to the origin of the medial umbilical ligament, and the entire nodal packet is freed, and clips are used to secure the pedicle.

Postoperative Details

Patients are either admitted for overnight observation or are sent home after an adequate observation period in the recovery room. A CBC count is obtained the morning after surgery. Overnight observation is recommended by some in case of delayed bleeding from small arteries or veins in the area of the lymph node packet.

The bladder catheter is removed, and a clear liquid diet is initiated as soon as the patient is alert and oriented. Patients receive oral pain medications, and they are placed on restricted activity for 10 days.

Complications

Multiple studies have addressed postoperative complications of the laparoscopic node dissection in comparison with the mini-laparotomy technique and the modified open technique. Early reports indicated an approximate 15% overall complication rate for the transperitoneal laparoscopic approach. However, as laparoscopic training and experience progresses, the overall complication rate has fallen and currently is similar to the mini-laparotomy approach.

Potential complications include hemorrhage, bladder or ureter injury, bowel perforation, deep venous thrombosis, pulmonary embolus, ileus, bowel obstruction, urinary retention, hypercarbia, obturator nerve injury, wound infection/dehiscence, lymphocele, and conversion to the open procedure. Most of these potential complications can be avoided with a careful technique, thorough inspection, and adequate repair of noted injuries during the procedure. Bowel perforation can be minimized by limiting the use of electrocautery in the area of the intestine that needs mobilization in order to expose the pelvic lymph nodes. A short burst of electrical energy is sufficient to create a full-thickness injury to the bowel. In addition, abrasions that occur during mobilization of the colon should be covered using horizontal mattress sutures placed laparoscopically (Baldwin, 2007).

By carefully identifying the obturator nerve (located in the posterior aspect of the dissection) prior to placing clips or removing the lymph node packet, injury usually can be avoided. The nerve is injured most commonly during the division of the superior and inferior aspects of the node dissection.

Conversion to open surgery occurs most commonly after an injury has occurred to the iliac vessels. Small holes in the artery or vein sometimes can be closed laparoscopically. However, if any doubt exists about the quality of repair, the patient should be converted to open surgery for closure of the vessel injury.

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