Pediatric Robotic Pyeloplasties: Initial Experience at a Single Center

Abstract

Purpose:

The purpose of this analysis was to review our initial experience of pediatric robotic-assisted pyeloplasties (RALPs). Our case series spanned a 7-year period (January 2004–February 2011). The initial 20 cases were reviewed retrospectively (RG group), and the later 20 cases were seen prospectively (PG group). We compared outcomes between these two groups.

Subjects and Methods:

After institutional review board approval, all charts were reviewed, and outcomes were based on postoperative imaging. For continuous variables t tests were performed, and for categorical variables Fisher's exact tests were performed. Statistical analysis was performed with SPSS version 17.0 software (SPSS, Inc., Chicago, IL).

Results:

There was no significant difference in demographics between the two groups. Median age at time of surgery was 64 months (PG) and 36 months (RG). Narcotic use was statistically similar among the groups when comparing median morphine intravenous equivalent per kilgram. Mean follow-up was 15.6 months (PG) and 41.8 months (RG). Postoperative imaging was stable or improved in 95% (PG) and 100% (RG). RALP in 1 patient in the PG group failed and later required repeat surgery (5%). The only identified significant difference between the two groups was surgical time. Mean operative time was reduced by over an hour between the two time periods (230 minutes for PG, 297 minutes for RG [P<.01]).

Conclusions:

The experience in pediatric RALP is growing at our institution. As this experience grows, the primary outcome that has changed is faster operative times. This increased efficiency does not correlate with compromised outcomes. We continue enrolling patients in our prospective database to strengthen the power of our outcomes analysis.

Introduction

The gold standard therapy for treatment of ureteropelvic junction obstruction is a pyeloplasty. Success rates with an open technique have reported success rates between 90% and 100%.^1–3 Minimally invasive techniques were started in an effort to minimize morbidity from the surgery. Early interventions with endoscopy had disappointing success rates,^4,5 but laparoscopy later surfaced and showed comparable outcomes to open surgery.^6–8 However, the learning curve to gain proficiency in laparoscopic reconstruction is quite high.

Robotic surgery has expanded the field of minimally invasive repair quickly. Some of the technical advantages include magnified three-dimensional vision, tremor reduction, and articulating instruments with six degrees of movement.^9,10 These factors have broadened the field of minimally invasive reconstruction to surgeons with more limited laparoscopic training.

Because the literature is still limited in pediatrics robotic reconstruction, we are summarizing here our experience over a 7-year span. We have seen comparable success rates and minimal morbidity from this approach.

Subjects and Methods

This study is a comparative analysis of a retrospective case series (RG group) and a prospective cohort (PG group). The retrospective case series is composed of the first 19 patients receiving robotic-assisted pyeloplasties (RALPs) at our institution (from January 2004 to April 2008). Of these patients, 1 patient received bilateral repair, resulting in 20 kidneys included in the analysis. In 2009, our department instituted a prospective database of all RALP cases. This second group of pyeloplasties comes from this study and includes the first 20 prospective patients (20 kidneys). These prospective patients were enrolled between March 2009 and February 2011. All procedures were performed by one surgeon.

The majority of cases (36 [90%]) were performed using the da Vinci^® S Surgical System robot (Intuitive Surgical, Sunnyvale, CA) (35 of the 40 cases). In the RG group, there were 4 cases performed using the first-generation da Vinci robot.

Surgical technique was similar in all 39 cases. Before the pyeloplasty was started, all patients underwent a cystoscopy with stent insertion. Camera access was obtained using open access through an 8.5- or 12-mm infraumbilical incision. Two working ports were placed. The first working port was midline between the umbilicus and the xiphoid. The second working port was in the ipsilateral lower quadrant lateral to the inferior epigastric vessels. The robot was docked over the ipsilateral shoulder. All procedures were performed by one surgeon.

Approval from Connecticut Children's Medical Center's Institutional Review Board was obtained for both the retrospective and prospective studies. Surgical times were defined as time of first incision to time of last suture. In 2 cases, the surgical time was not precisely recorded. Two other cases were converted to standard laparoscopy because of technical issues. These 4 cases were excluded from our surgical times.

Our primary surgical outcome was postoperative imaging and any need for subsequent surgery. For continuous variables t tests were performed, and for categorical variables Fisher's exact tests were performed. Statistical analysis was performed using SPSS version 17.0 software (SPSS, Inc., Chicago, IL).

Results

Both the RG group and the PG group were demographically similar (Table 1). The majority of patients were male (70% PG, 79% RG) and diagnosed prenatally (50% PG, 47% RG). Of those patients not diagnosed prenatally, median age of diagnosis was approximately 7 years old (87 months) in the PG group and 9 years old (110 months) in the RG group. Pain was the primary indication for surgery (35% PG, 47% RG), followed by decreased renal function in the PG group and worsening hydronephrosis in the RG group. Two surgeries in the RG group were salvage repairs.

Table 1.

Comparison of Prospective and Retrospective Patient Characteristics

Characteristic	Prospective cohort	Retrospective cohort	P
Number of patients	20	19	—
Number of kidneys	20	20	—
Gender [% (n)]			.72^a
Male	70% (14)	79% (15)
Female	30% (6)	21% (4)
Prenatal diagnosis [% (n)]			1.0^a
Yes	50% (10)	47% (9)
No	50% (10)	53% (10)
Median age at diagnosis (months)	87 (6–166)	110 (40–186)	.23^b
Surgical indication [% (n)]			.08^a
Pain	35% (7)	47% (9)
Worsening hydronephrosis	15% (3)	32% (6)
Decreased renal function	30% (6)	5% (1)
Parent driven	20% (4)	5% (1)
Other	0% (0)	11% (2)

Fisher's exact test was used.

The Mann–Whitney U test was used.

Median age at time of surgery was 64 months (PG) and 36 months (RG). Median weight at time of surgery was 17 kg (PG) and 15 kg (RG). Length of stay between the two groups was comparable, with a median hospital stay of 1 day for both groups, with the majority of patients in both groups discharged 1 day post-surgery (70% PG, 55% RG) (Table 2).

Table 2.

Comparison of Prospective and Retrospective Operative Characteristics

Characteristic	Prospective cohort	Retrospective cohort	P
Median age at surgery (months) (range)	64 (7–198)	36 (5–199)	.48^a
Median weight at surgery (kg)	17 (8–77)	15 (8–71)	.51^a
Median length of stay (days)	1 (1–3)	1 (1–5)	.72^a
Median surgical time (minutes)	230 (153–378)	289 (230–388)	.01^a
Median intravenous morphine equivalent (mg/kg)	0.06 (0.05–0.32)	0.28 (0.18–0.49)	.23^a

The Mann–Whitney U test was used.

RALP surgical time was significantly shorter in the PG group compared with the RG group (P<.01). With increased experience, mean operative time was reduced by almost 1 hour (230 minutes for PG, 289 minutes for RG). The majority of this reduction was seen after the first 5 cases. Because only 4 cases were performed using the first-generation da Vinci system, we cannot discern if the robotic system contributed to improved surgical efficiency.

Patients from both groups had indwelling stents placed during their procedure. Median in-hospital narcotic use was statistically similar between the groups when comparing morphine intravenous equivalent per kilogram (0.06 mg/kg for PG, 0.28 mg/kg for RG).

There was no statistically significant difference in resolution of hydronephrosis between the two groups. Postoperative imaging was stable or improved in 95% of PG patients and 100% of RG patients (Table 3). One patient in the prospective group had a failed initial RALP and required repeat surgery. Mean follow-up time was significantly longer in the RG group than in the PG group (16 months for PG, 42 months for RG).

Table 3.

Comparison of Prospective and Retrospective Outcome

Characteristic	Prospective cohort	Retrospective cohort	P
Resolution of hydronephrosis [% (n)]			.33^a
Failed	5% (1)	0% (0)
Resolved/improved/stable	95% (19)	100% (20)
Follow-up (months) (mean±SD)	15.6±7.8	41.8±14.3	<.001^b

Fisher's exact test was used.

The t test was used.

SD, standard deviation.

Discussion

The technique of standard laparoscopic pyeloplasty was first described in adults in 1993.^11,12 It then gained exposure in pediatrics when described by Peters et al. in 1995.¹³ Although this has been shown to be a safe and effective technique, there are some limitations. The technical challenges of two-dimensional imaging, difficult intracorporeal suturing, and limited range of movement by the instruments all lead to a steep learning curve.

The use of robotics can facilitate the benefits of minimally invasive surgeon even if standard laparoscopic skills are limited.¹⁴ Despite a smaller working space and a smaller array of equipment in 5-mm ports, we have found RALP to be an appealing option for repair of ureteropelvic junction obstruction in children. As with other series, we found increasing proficiency with increased experience.¹⁵

The quick return to normal activities for the child will lead to quicker return to work by that patient's parents. This association with human capital gains is an additional benefit of surgical approach.¹⁶

Translating the use in robotics for children can be more challenging because of the smaller working space and a limited choice of robotic instruments for 5-mm ports. RALP in children is still evolving but has definitely gained popularity in the past decade. To gain further acceptance, RALP must show comparable outcomes to the gold standard of an open pyeloplasty. The literature on RALP in children has been encouraging, but it is still limited in volume. The robotic benefits of a shorter hospital stay and a quicker return to normal activity has been proven in both the adult and pediatric populations.¹⁰

The initial outcomes with this surgical approach have been favorable.^10,17–20 RALP has been used in a variety of situations: transperitoneal and retroperitoneal in approach,²¹ infant repairs, salvage repair,²² and bilateral repairs.²³ The type of repair can be a standard dismembered pyeloplasty as well as other techniques such as Fenger, Y-V plasty, and Hellstrom variations.²⁴ In addition, there is growing literature showing higher parental satisfaction with robotic pyeloplasties compared with open repairs.²⁵

Our series supports the growing literature in the field of pediatric urology. We are seeing faster operative times with excellent postoperative results. Patients are recovering quickly and have minimal scarring. As the literature expands, one questions if the gold standard for treatment of a ureteropelvic junction obstruction is an open or minimally invasive pyeloplasty.

Conclusions

Experience in pediatric robotic pyeloplasty continues to grow, both at our institution and globally. Our series strengthens the existing pediatric literature that shows high success rates with a robotic approach.

We recognize some weaknesses in our report. This is not a randomized case series comparing open, laparoscopic, and robotic surgical approaches. We find very few families who opt for an open approach when robotics is available for patients of all ages. Therefore enrollment for such a comparative series would be quite difficult.

Our series is a comparison of retrospective and prospective data. However, as we performed our retrospective analysis, it clarified how to design our prospective database. Combining the statistics from the two groups gives the best summary of our RALP experience in a 7-year period.

We are encouraged to see improved efficiency with experience but no drop in success rates and recovery.

Footnotes

Disclosure Statement

No competing financial interests exist.

References

Brooks

et al. Comparison of open and endourologic approaches to the obstructed ureteropelvic junction. Urology, 1995; 46:791–795.

Notley

, Beaugie

. The long-term follow-up of Anderson-Hynes pyeloplasty for hydronephrosis. Br J Urol, 1973; 45:464–467.

Persky

, Krause

, Boltuch

. Initial complications and late results in dismembered pyeloplasty. J Urol, 1977; 118:162–165.

Szydelko

et al. Antegrade endopyelotomy versus laparoscopic pyeloplasty for primary ureteropelvic junction obstruction. J Laparoendosc Adv Surg Tech A, 2009; 19:45–51.

Dimarco

et al. Long-term success of antegrade endopyelotomy compared with pyeloplasty at a single institution. J Endourol, 2006; 20:707–712.

Braga

et al. Pediatric laparoscopic pyeloplasty in a referral center: Lessons learned. J Endourol, 2007; 21:738–742.

Chacko

et al. Pediatric laparoscopic pyeloplasty: Lessons learned from the first 52 cases. J Endourol, 2009; 23:1307–1311.

El-Ghoneimi

. Paediatric laparoscopic surgery. Curr Opin Urol, 2003; 13:329–335.

Peters

. Robotically assisted paediatric pyeloplasty: Cutting edge or expensive toy? BJU Int, 2004; 94:1214–1215.

10.

Lee

et al. Pediatric robot assisted laparoscopic dismembered pyeloplasty: Comparison with a cohort of open surgery. J Urol, 2006; 175:683–687discussion 687.

11.

Schuessler

et al. Laparoscopic dismembered pyeloplasty. J Urol, 1993; 150:1795–1799.

12.

Kavoussi

, Peters

. Laparoscopic pyeloplasty. J Urol, 1993; 150:1891–1894.

13.

Peters

et al. Pediatric laparoscopic dismembered pyeloplasty. J Urol, 1995; 153:1962–1965.

14.

Uberoi

et al. Minimally invasive surgical management of pelvic-ureteric junction obstruction: Update on the current status of robotic-assisted pyeloplasty. BJU Int, 2009; 104:1722–1729.

15.

Leveillee

, Williams

. Role of robotics for ureteral pelvic junction obstruction and ureteral pathology. Curr Opin Urol, 2009; 19:81–88.

16.

Behan

et al. Human capital gains associated with robotic assisted laparoscopic pyeloplasty in children compared to open pyeloplasty. J Urol, 2011; 186,4 Suppl:1663–1667.

17.

Casale

. Robotic pyeloplasty in the pediatric population. Curr Opin Urol, 2009; 19:97–101.

18.

Atug

et al. Robotic assisted laparoscopic pyeloplasty in children. J Urol, 2005; 174:1440–1442.

19.

Passerotti

et al. Laparoscopic reoperative pediatric pyeloplasty with robotic assistance. J Endourol, 2007; 21:1137–1140.

20.

Ferhi

et al. Promising functional outcomes obtained with robot-assisted laparoscopic pyeloplasty: A single-center experience. J Endourol, 2009; 23:959–963.

21.

Olsen

, Rawashdeh

, Jorgensen

. Pediatric robot assisted retroperitoneoscopic pyeloplasty: A 5-year experience. J Urol, 2007; 178:2137–2141discussion 2141.

22.

Hemal

et al. Robot assisted laparoscopic pyeloplasty in patients of ureteropelvic junction obstruction with previously failed open surgical repair. Int J Urol, 2008; 15:744–746.

23.

Kutikov

et al. Robot assisted pyeloplasty in the infant—lessons learned. J Urol, 2006; 176:2237–2239discussion 2239–2240.

24.

Gundeti

et al. Further experience with the vascular hitch (laparoscopic transposition of lower pole crossing vessels): An alternate treatment for pediatric ureterovascular ureteropelvic junction obstruction. J Urol, 2008; 180,4 Suppl:1832–1836discussion 1836.

25.

Freilich

et al. Parental satisfaction after open versus robot assisted laparoscopic pyeloplasty: Results from modified Glasgow Children's Benefit Inventory Survey. J Urol, 2010; 183:704–708.