Cite this chapter
Altschuler, J., Attalla, K., Sfakianos, J. (2024). Robotic-Assisted Pelvic Lymph Node Dissection in the Management of High-Risk Bladder Cancer. In: John, H., Wiklund, P. (eds) Robotic Urology. Springer, Cham. https://doi.org/10.1007/978-3-031-49428-4_24
Pelvic lymph node dissection at the time of radical cystectomy remains an important part of surgical management of patients with high-risk urothelial carcinoma of the bladder. Open technology has long been considered the "gold standard" surgical approach, however, the maturity of minimally invasive techniques has led to the increasing use of robotic surgery in the treatment of this disease.
As described in the first lymph node dissection series published by Skinner et al. in 1982, pelvic lymph node scircum ssection (PLND) remains an essential diagnostic and therapeutic component in the surgical management of high-risk non-muscle-invasive and muscle-invasive bladder cancer (MIBC) [1]. The basis for high-quality PLND at the time of radical cystectomy (RC) stems from the well-established pattern of bladder cancer metastasis; Pelvic lymph nodes are the site most affected by metastases, followed by bone, lung, liver, and peritoneum [2]. Among the pelvic lymph nodes, the obturator and internal iliac lymph nodes are the most commonly affected [3], and Abol-Enein et al. demonstrated that these are the two sentinel sites for bladder drainage [4]. In addition, other major and secondary sites of involvement include the presacral, commonal, interaortic, and paraluminal lymph node bundles [5]. Presacral lymph nodes are particularly important because they receive drainage from the triangular and posterior walls of the bladder [6].
High-quality lymph node dissection at RC (generally defined in the literature as minimal lymph node yield within an anatomical template) has demonstrated improved survival outcomes [7,8]. Herr et al. published a series of 762 patients at Memorial Sloan Kettering Cancer Center who underwent bilateral PLND between 1980 and 1990 and determined that the number of lymph nodes examined by pathologists was directly related to improved survival [9]. This survival benefit was seen in both node-negative and node-positive patients. The anatomical template for these patients includes internal, external, and common iliac lymph nodes, as well as presacral, peribladder, and obturator lymph nodes. Other studies have shown that the ratio of lymph node density or number of positive lymph nodes to the total amount of lymph node tissue removed is an important indicator of the quality of lymph node dissection [10,11].
The degree of anatomy of PLND at RC has also been extensively studied for its correlation with oncology and survival outcomes. Localized PLND, which includes tissue within the obturator fossa, is infrequently performed due to concerns about insufficient detection of node-positive disease [12]. Standard PLND involves the excision of obturator, medial, lateral, and distal common iliac lymph nodes, characterized by the proximal common iliac bifurcation, distal common iliac bifurcation, medial iliac wall, and lateral genitofemoral nerve [13]. Standard PLND has been shown to capture 90 to 95 percent of node-positive patients [13,14]. Extended pelvic lymph node dissection also includes presacral and common iliac lymph node tissue up to the level of the aortic bifurcation, whereas hyperextended pelvic lymph node dissection involves lymph node tissue down to the level of the inferior mesenteric artery [13]. Bochner et al. studied 144 patients who received standard or prolonged PLND at RC and found no statistically significant difference between the two groups in the percentage of node-positive patients, although prolonged PLND produced more positive lymph nodes [15]. Several studies have compared ultra-prolonged versus prolonged PLND and found no statistically significant difference in recurrence-free survival or overall survival between the two cohorts [16,17].
Robot-assisted PLND
RC is a major surgery with significant morbidity due to the complexity of the surgical procedure, including the excision and reconstruction portion, duration of anesthesia, length of hospital stay, and significant medical comorbidities in a typical elderly population with bladder cancer. Recently, many urologists have tried robotic-assisted approaches to RC to help shorten hospital stays, facilitate postoperative recovery, and alleviate short- and long-term complications [18]. To date, there have been a number of prospective randomized clinical trials comparing open versus robotic-assisted RC. Bochner et al. first studied this in 2010-2013, randomizing 60 patients to robotic-assisted RC/PLND and 118 patients to open-label RC/PLND [18]. Both groups received open urinary diversion. There was no statistically significant difference in the incidence of grade 2-5 complications at 90 days between the two cohorts, although the robotic cohort had lower estimated blood loss and longer time in the operating room compared to the open cohort. There was no statistically significant difference in lymph node yield between the two groups. A few years later, the RAZOR trial (RAZOR trial) was a randomized, multicenter, noninferiority, phase 3 trial in patients with high-risk bladder cancer with a primary endpoint of PFS [19]. The study showed that robot-assisted RC was non-inferiority in terms of 2-year PFS, with similar rates of adverse events in both groups. Similar to the previous study by Bochner et al. [18], there was no difference in lymph node yield between the two groups.
technology
Aseptic preparation and entry into the peritoneal cavity is performed in a standard manner, as described in the previous text for robotic radical cystectomy (Figure 1). 24.1). Briefly, an 8mm camera port is placed about 5 cm above the umbilicus. The other two 8mm ports are located 4 finger width and 2 finger width below the camera port. On the patient's right side, a 12 mm auxiliary port is placed on the outside of the aforementioned 8 mm port and two finger widths over the tail two finger widths of the other four fingers. This port can be used to clamp lymphatic vessels during PLND. On the patient's left side, repeat the same operation with a 15 mm auxiliary port, through which an 8 mm port can be placed and used for docking arm #1. Finally, a 12 mm accessory port is placed four finger widths apart from the skull at the camera port on the patient's right side, taking care to avoid the sickle ligament. The robot docks sideways with the patient in a steep Trendelenburg position.
Figure 24.1
Robot port placement
The authors preferred PLND after radical cystectomy, after the bladder specimen was placed in the specimen bag. Place the monopolar curved scissors in the right arm, the Maryland bipolar forceps in the left arm, and the Cadiere forceps in the fourth arm. PLND is performed similarly in men and women, with the exception of vasectomy division in men and round ligament division in women, after bladder mobilization from the lateral wall of the pelvis. This article describes an extended PLND.
The authors preferred the following order of PLND: complete resection of the entire right pelvic lymph node, presacral lymph node dissection (placing the right pelvic and presacral lymph nodes in a single specimen bag), followed by left pelvic lymph node dissection (placed in a separate specimen bag). A 10 cm Endocatch bag is used to remove the lymph node specimen through the right auxiliary port. After lymph node dissection, a string of specimen bags containing the bladder, right pelvic and presacral lymph nodes, and left pelvic lymph nodes is clamped to facilitate removal during specimen retrieval.
Any adhesions between the sigmoid colon and the lateral wall of the pelvis are dissolved, and the descending/ascending colon is released medially by dissection along the Toldt line alba, which should help visualize the common iliac bifurcation into the external and internal iliac arteries.
Common iliac artery and external iliac artery lymph node dissection
The lymph node pack lifts from the anterior and lateral borders of the common iliac artery. The tissue is released laterally until the genitofemoral nerve delineating the lateral border of PLND is identified (Figure 1). 24.2). The distal distal boundary of the dissection is then delineated from the distal end to the circumflex iliac vein. The small perforated vessel laterally inserted into the psoas muscle was finely coagulated with bipolar energy (Figure 1). 24.3). Dissect lymphoid tissue anterior to the common iliac artery and external iliac artery using the "split and roll" technique.
Figure 24.2
Identification of the genitofemoral nerve, which represents the lateral boundary of the dissection
Figure 24.3
The perforated vessel inserted into the psoas muscle coagulates to prevent avulsion of the small blood vessels and to release the lymph node pack from the lateral limit of the dissection
External iliac vein, obturator foramen, and endolymphadenectomy
Peribladder fat is the medial border of PLND. The Hemolock clip is placed at the caudal end of the PLND, and the Cooper ligament intersects the circumflex iliac vein at the Cloquet node (Figure 1). 24.4). Delicate lymphocytosis in this area is essential to prevent symptomatic lymphocyst formation. Dissect the tissue along the external iliac vein by retracting the lymphoid tissue medially and releasing the lymph node pack from the venous wall and pelvic lateral wall, taking care to approach the pubic bone and pelvic lateral wall, as this favors dissection at the avascular plane. At this point, the obturator nerve and blood vessel are identified, and the lymph node envelope is retracted from the obturator nerve and gently retracted intracranial in front of the nerve (Figure 1). 24.5). Then pay attention to the lower abdominal lymph node pack. Cranial dissection deep in the obturator nerve shows the inferior abdominal artery and can also be identified by anterograde dissection along the common iliac artery. The dissection lateral to the external iliac artery is carefully directed down to the Marsil triangle (bordered laterally by the psoas major muscle, medially bounded by the common iliac artery, and posterior to the obturator nerve), where the lateral boundary of the external iliac vein is determined. This procedure aids in obturator lymph node dissection by releasing the lymph node pack laterally from the psoas muscle (figure 1). 24.6). The lymph node envelope is released from the lateral wall of the pelvis distal and posterior to the obturator nerve.
Figure 24.4
Hemolock clamping was used to achieve delicate lymphatic accumulation at the distal end of the dissection
Figure 24.5
Obturator lymph node dissection. Carefully scan the tissue over the skull in front of the obturator lymph nodes
Figure 24.6
The dissection lateral to the external iliac artery is directed toward the Marcier triangle (bordered laterally by the psoas major muscle, medially by the common iliac artery, and posterior to the obturator nerve), where the lateral boundary of the external iliac vein is determined. This procedure aids in obturator lymph node dissection by releasing the lymph node pack laterally from the psoas muscle
Presacral lymph node dissection
Dissection begins posterior to the sigmoid mesocolon. Aortic bifurcation is visible, and the lymph node wrap is carefully elevated from the left common iliac vein and sacral promontory (Figure 1). 24.7). Meticulously use bipolar cautery control to perforate branches from these vessels. The sigmoid mesocolon is retracted laterally to expose the presacral space, taking care to identify the plane between the plexus and lymphoid tissue. The completed pelvic lymph node dissection is shown in the figure. 24.8. Pelvic vascular skeletonization with the left ureter having passed through the sigmoid mesocolon.
Figure 24.7
Presacral lymph node dissection
Figure 24.8
Pelvic lymph node dissection is done