Robotic Pyeloplasty: Step by Step Surgical Technique

Symptoms and signs in adults might include recurrent flank pain, urinary tract infections and pyelonephritis that require surgical correction. Due to the European Association of Urology (EAU) Guidelines, indications for surgical treatment include impaired split renal function of less than 40%, a decrease of split renal function of more than 10% in subsequent studies, increased antero-posterior diameter on abdominal ultrasound and grade III/IV dilatation of the renal pelvis [3]. It has been reported that, laparoscopic, retroperitoneoscopic and robotic approaches have similar success rates compared to open surgical approach in experienced centers [3].


Introduction
Uretero-pelvic junction (UPJ) obstruction leads to impaired transport of urine from the renal pelvis to the ureter that might cause increased pressure in the renal pelvis and deterioration of renal function. Etiology might include congenital causes, acquired factors such as infections, stones, trauma due to instrumentation leading to fibrosis and presence of an aberrant crossing vessel [1,2].
Symptoms and signs in adults might include recurrent flank pain, urinary tract infections and pyelonephritis that require surgical correction. Due to the European Association of Urology (EAU) Guidelines, indications for surgical treatment include impaired split renal function of less than 40%, a decrease of split renal function of more than 10% in subsequent studies, increased antero-posterior diameter on abdominal ultrasound and grade III/IV dilatation of the renal pelvis [3]. It has been reported that, laparoscopic, retroperitoneoscopic and robotic approaches have similar success rates compared to open surgical approach in experienced centers [3].

Surgical Technique
Herein, the surgical technique that we apply is summarized. Surgical robotic pictures are obtained from the authors' own robotic surgical procedures.

Patient positioning
In the operating room, patient is positioned in the 60° lateral decubitis position with proper paddings.

Port sites:
We use open trocar insertion technique in our cases. Overall, 4 trocars are used ( Figure 1). A 12 mm sized trocar for robotic camera is inserted into the abdominal cavity lateral to the rectus abdominis muscle at the level of the umbilicus. Intra-abdominal pressure is set to 15 mm Hg CO 2 . Following insertion of the 0° 3D robotic camera into the abdominal cavity, an 8 mm sized robotic port is inserted under direct vision into the abdominal cavity located approximately 8 cm away from the camera port close to the costal arcus on the midclavicular line. A second 8 mm sized robotic port is inserted under direct vision approximately 8 cm away from the camera port close to the anterior superior iliac spine. These 3 ports form a triangle facing the kidney. A 10 mm sized assistant port is inserted into to abdominal cavity approximately located 4-5 cm lateral to the camera port for introducing sutures, suction, JJ stent and removing tissue cut portions.  respectively. An endoscopic suction is used for irrigation and suction of intra-abdominal body fluids (urine and blood) and smoke. An endoscopic needle holder is used to introduce and remove suture materials into the abdominal cavity. An endoscopic grasper is used to remove tissue pieces such as excised UPJ section.

Advances in Robotics & Automation
Following identification of the white line of Toldt, colon is identified and mobilized medially (Figure 2a and 2b). Thereafter, ureter is detected in the retroperitoneum and dissected off the surrounding structures (Figure 3a and 3b). Then, ureter is dissected up to the renal pelvis (Figure 4a-c). It is important to note and not to damage the presence of a crossing vessel that might exist in the retroperitoneum and that might cause UPJ obstruction, compressing the ureter and supplying the kidney (Figure 4a-4c). Renal pelvis is identified and fat tissue overlying the renal pelvis is dissected off. In most cases, renal pelvis appears quiet dilated and hydronephrotic ( Figure 5).
A stitch by using 4/0 vicrly suture with atraumatic needle is put on the anterior site of the upper ureter in order to mark the anterior surface ( Figure 6). Then, ureter is cut above the suture completely ( Figure 7). The obstructed UPJ tissue is excised and removed for histopatho logic investigation. Thereafter, ureter is spatulated at its cut end posteriorly (Figure 8). Dilated and hydronephrotic renal pelvis is cut and removed for histopathological evaluation (Figure 9a-9c). As a result, the size and capacity of the renal pelvis is reduced to its normal limits. Figure 10 shows the appearance of the prepared renal pelvis and ureter for anastomosis. A JJ stent is inserted through the 10 mm sized assistant port into the ureter (Figure 11a). Thereafter, anastomosis between the spatulated ureter and the renal pelvis is initiated starting from the posterior by using 4/0 vicrly suture with atraumatic RB-1 needle (Figure 11b). Excised renal pelvis is closed by using the same suture (Figure 12a and 12b). Finally, UPJ anastomosis is completed with preservation of the crossing vessel (Figure 13a and 13b).
Intra-abdominal pressure is dropped down to 5 mm Hg and the surgical area is checked for bleeding. Following hemostasis, a drain is inserted into the abdominal cavity close to the operation field. Abdominal ports are removed under direct vision and port sites are closed.   Minimally invasive pyeloplasty including robotic and laparoscopic approaches were reported to have lower morbidity, shorter duration of hospital stay, and less blood loss compared with open surgical approach [4]. On the other hand, outcomes of both laparoscopic and robotic pyeloplasty approaches were reported to have durable with similar success rates in long term. Robotic approach was suggested having the advantages of enabling quicker tissue dissection, reconstruction, and intracorporeal suturing and antegrade double-J stenting for the console surgeon. Compared to laparoscopic approach, operating time was found to be decreased with better ergonomics for the surgeon in robotic approach [5]. Additionally, parent satisfaction was reported to be greater in robotic pyeloplasty than with open surgery regarding amount of cosmesis and recovery [6]. Table 1 summarizes selected series of the published robotic pyeloplasty literature with highest number of patients [7][8][9][10][11][12][13][14]. More than 95% success rates were reported by most series. Some of these series include both primary and secondary cases that might have an      impact on operation time [7][8][9][10][11][12][13][14]. Mean blood loss was less than 100 cc in most series [7][8][9][10][11][12][13][14]. Duration of hospital stay was between 1-2.5 days which is one of the main advantages minimally invasive surgery including laparoscopic approach [7][8][9][10][11][12][13][14].
Robotic laparoendoscopic single-site (LESS) pyeloplasty is one of the recently developing techniques that attract the attention of both urologists and patients. A number of reports exist in the literature related with this subject. It has been reported that robotic LESS pyeloplasty can be safely performed in selected patients with currently available robotic equipments [15]. Very recently; outcomes of 140 adult patients who underwent LESS were reported in a multi-institutional study [16]. Mean patient age was 39.9 ± 15.7 years. More than 90% of the patients underwent dismembered reconstructions. Mean operative time was 202.1 ± 47 minutes and estimated blood loss of was 61.2 ± 44.6 mL. Robotic LESS surgery was performed in 31 patients. No patients required conversion to open surgery and no intraoperative complication occurred. Duration of hospital stay was 2.4 ± 1.6 days. Overall 90-day postoperative complication rate was reported to be 18.6%. Of those, most were low-grade complications due to Clavien classification. More than 93% of the patients had symptoms resolved and more than 94% of the patients had radiologic improvement in UPJ obstruction after a mean follow-up of 14.0 ± 10.8 months.
Retroperitoneal robotic approach attracts interest having the advantage of avoiding transperitoneal access and possible problems related with transperitoneal approach. However, retroperitoneal space is limited compared to transperitoneal approach that might be a limiting factor for robotic surgery. Kaouk et al. evaluated feasibility of robotic dismembered pyeloplasty and concluded that this approach could be performed efficiently. Their surgical outcomes were detected to be comparable to published laparoscopic and transperitoneal robotic dismembered pyeloplasty series in adults [17]. Likewise, Cestari et al. evaluated the outcomes of 36 patients who underwent retroperitoneal robotic pyeloplasty and 19 underwent transperitoneal approach. The overall success rate was found to be 96%. They concluded that robotic pyeloplasty performed either retroperitoneally or transperitoneally is a feasible and reproducible surgical approach [18].
Finally, cost is an important issue related with robotic surgery. Casella et al. evaluated the cost of robotic pyeloplasty [19]. They detected that operation time was significantly shorter in robotic approach compared to pure laparoscopy and no significant difference