Pediatric Laparoscopic and Robotic Pyeloplasty
WALID A. FARHAT
Historically, open pyeloplasty has been the standard treatment for congenital or acquired ureteropelvic junction (UPJ) obstruction in adults and children, with overall success rates of 90% to 100% (1,2,3). Although endopyelotomy (4) and retrograde dilation (5) are alternative methods of managing UPJ obstruction in children (6), the success of these two procedures is inferior to that reported for conventional dismembered pyeloplasty (7). Advances in technology have played a significant role in the therapeutic management of UPJ obstruction and have enabled the introduction of laparoscopic and robot-assisted laparoscopic pyeloplasty over the last few years. Continued interest in minimally invasive treatment for UPJ obstruction has inspired new questions about the optimal laparoscopic approach for treating this disease.
Laparoscopic pyeloplasty was introduced in adults in 1993 (8,9). In the initial reports, the operative time ranged from 3 to 7 hours, but the procedure has gradually gained in popularity and acceptance with a reported success rate of over 95% (10,11,12,13,14,15,16). Yeung et al. (15) reported their initial experience with retroperitoneal laparoscopic pyeloplasty in 13 children, one of who required open conversion. The mean operative time was 143 minutes (range 103 to 235 minutes). El-Ghoneimi et al. (16) reported their experience with 50 retroperitoneal laparoscopic pyeloplasties in children aged between 22 months and 15 years. Conversion to open surgery was necessary in four cases due to technical difficulties during suturing. Mean hospital stay was 2 days, and return to full activities occurred within 5 days of surgery. The longer time needed for the retroperitoneal approach is almost certainly related to the limited working space that renders suturing more difficult.
Approximately 1% of prenatal ultrasounds detect hydronephrosis in the fetus. In 50% of these cases, UPJ obstruction causes the condition. UPJ obstruction is more common in males and affects the left kidney more often than the right. About 10% to 30% of cases occur in both kidneys (bilaterally) (11). Congenital abnormalities are the most common cause of UPJ obstruction in children. The condition often results from an abnormality in the muscles that surround the UPJ causing an intrinsic narrowing. It may also be caused by an abnormality in the structure or position of the ureter such as a high insertion onto the renal pelvis. Lower pole renal blood vessels crossing over the ureter can cause an obstruction as well. Other etiologies of UPJ obstruction are compression of the ureter caused by inflammation, retroperitoneal fibrosis, kidney stones, or scar tissue from previous surgery to correct UPJ obstruction. Symptoms of UPJ obstruction are typically seen in the older children but can be seen in infants and include the following: back or flank pain, hematuria, failure to thrive, flank mass, and/or pyelonephritis.
UPJ obstruction that causes hydronephrosis is usually diagnosed by prenatal ultrasound. Neonatal patients suspected to have this condition are evaluated for the obstruction using renal ultrasound and diuretic renography. Magnetic resonance urography has also become part of the armamentarium for radiologic imaging. In some children, a voiding cystourethrogram (VCUG) might be utilized to rule out vesicoureteral reflux as a cause of the hydronephrosis or as a concomitant finding.
Laparoscopic pyeloplasty includes two modalities of delivery: conventional laparoscopy and robotic-assisted laparoscopy. For this chapter, both modalities will be referred to as laparoscopic pyeloplasty. A section of the chapter at the end will discuss added nuances of the robotic platform.
The indications for laparoscopic pyeloplasty are similar to those for an open pyeloplasty. They encompass increasing hydronephrosis, progressive deterioration of renal function, recurrent urinary tract infection (UTI), and persistent pain. The introduction of refined instrumentation and more experience with intracorporeal suturing allows reconstructive laparoscopy to be implemented in the pediatric population, with multiple techniques of pyeloplasty described in the literature (12). One of the earliest descriptions of the transperitoneal Anderson-Hynes laparoscopic pyeloplasty in pediatric patients by Tan et al. (13) recommended that it should not be performed in children younger than 6 months of age. The advent of improved 3-mm instrumentation and laparoscopic telescopes has allowed better suture manipulation and visualization, making it feasible even in the infants younger than 6 months of age (14). The key point to performing a laparoscopic pyeloplasty in the infant is based on the geometry of the patient’s body habitus. A triangle is constructed utilizing the umbilicus as the apex with the remaining points being lateral to the ipsilateral rectus muscle subcostal and at the level of the anterior superior iliac spine.
Whereas open pyeloplasty has long been described, laparoscopic pyeloplasty has only recently been reported, and long-term outcome data are still being evaluated. As laparoscopic pyeloplasty is technically challenging, this procedure was initially restricted to those medical centers with advanced laparoscopic surgeons. With increasing experience, however, laparoscopic pyeloplasty in children is more commonly being considered as the initial treatment for UPJ obstruction (17). This procedure maintains the benefits of the endoscopic approaches, including decreased postoperative pain, short hospitalization, and reduced postoperative recovery time while demonstrating success rates comparable to those of the conventional open approach (18,19).
Open pyeloplasty still remains the gold standard for correcting UPJ obstruction with a high success rate done either through a flank, dorsal lumbotomy, or anterior muscle-splitting incision. Proponents of open pyeloplasty have shown that this procedure can be done without placement of an indwelling ureteral stent along with simple percutaneous drainage either by a nephrostomy tube or single Penrose drain (1,2).
Endopyelotomy and retrograde dilation are also alternative methods of managing UPJ obstruction in children. Endopyelotomies are performed in the same fashion as in adults either by a percutaneous approach or ureteroscopically in a retrograde manner (4). The long-term success rate of endopyelotomy is less than the standard open or laparoscopic approaches (4,12,13,14). Retrograde dilation has virtually no role in pediatrics due to its high failure rate requiring a subsequent procedure (5).
LAPAROSCOPIC SURGICAL TECHNIQUE AND STEPS
Initial cystoscopy and ureteric stenting is left to the discretion of the surgeon and may not be necessary (20,21). An indwelling Foley catheter is placed to gravity drainage.
Positioning of the patient is crucial as it facilitates optimal ergonomics for the surgeon and increased access to the operative space. For both a transperitoneal and retroperitoneal approach, the patient is placed in a lateral or semilateral decubitus position in close proximity to the posterior edge of the table, the table is flexed, the kidney rest is elevated, appropriate padding is applied, and the patient is secured with 2-inch tape and a safety belt. An option for the retroperitoneal approach described by Yeung et al. (15) is a modified semiprone position with the left flank up or a 45-degree right lateral decubitus position (for right-sided obstruction) to allow the subsequent ureteropelvic anastomosis using the right hand (for a right-handed surgeon). Another option utilized for the transperitoneal approach is to place the patient supine with a slight 30-degree rotation of the ipsilateral side. The patient is then secured to the table with 2-inch silk tape (Fig. 102.1). The table can then be rotated as needed after visualization of the intraperitoneal field. This approach can be utilized on the left side allowing the colon to stay lateral to the left kidney so a transmesenteric window is unobstructed. As far as trocar placement, a fundamental concept that is important to implement is that conventional laparoscopy is ergonomically favored by triangulation of ports, whereas the robotic platform will function better with the ports arranged in as straight a line as possible with at least 4 cm between all ports.