Laparoscopic pyeloplasty is an effective treatment for ureteropelvic junction obstruction, similar to robot-assist pyeloplasty and open pyeloplasty.[1–3] The best method of trans-anastomotic urinary drainage after pyeloplasty is still controversial among pediatric urologists, because the existing options all have their disadvantages. To resolve this issue, “stentless” pyeloplasty has become an active area of research in recent years, but there are concerns involving prolonged urine leakage, impaired postoperative antegrade flow due to urinary tract edema, and the requirement of a secondary procedure. Implantation of a double-J stent has become a routine means of urine drainage, and this procedure is credited for its excellent drainage and prolonged ureteral dilation. However, an in situ double-J stent results in an artificial vesicoureteral reflux, predisposing the affected children to the development of renal parenchymal damage, with a higher incidence of bacterial infection. The requirement of re-operation for stent removal further limits the applicability of the double-J stent in pediatric patients, judging from the fact that Food and Drug Administration (FDA) warns about the long-term adverse neurodevelopmental effects brought by prolonged or repeated anesthesia in infants.
External stents for urine drainage, such as a nephrostomy tube or nephron-urethral stent, have been proposed as a practical approach to avoid the side effect of double-J stenting. These external stents exit the kidney through the renal parenchyma or pelvis, but they also have the disadvantages of blood or urinary leakage from the kidney after stent removal.[8,9] Here, we present a new therapeutic approach for urine diversion following laparoscopic pyeloplasty in children, the trans-uretero-cystic external urethral stent (TEUS) (Fig. 1). In the present study, we compared patient outcomes between those treated with a TEUS and those treated with a double-J stent.
2 Materials and methods
2.1 Ethical approval
We obtained ethical approval for this study from our institutional Research Ethics Board. Written informed consent was obtained from individual participants.
We retrospectively reviewed 99 patients with congenital ureteropelvic junction obstruction (UPJO) who underwent standard laparoscopic pyeloplasty between July 2015 and June 2017. Renal ultrasonography had been performed for all patients presenting with backache or for those with a history of hydronephrosis on ultrasound in outpatient clinic, and the anteroposterior diameter of the renal pelvis and caliceal diameter were measured for preparation for operation. The inclusion criteria of this study were pure congenital UPJO without other renal deformities. The exclusion criteria included those undergoing external trans-renal pelvic stent placement (n = 4), “stentless” pyeloplasty (n = 1), and redo-pyeloplasty (n = 1) as well as those with suspected concurrent vesicoureteral junction obstruction (n = 3) and those lost to follow-up after operation (n = 5). The remaining 85 patients underwent laparoscopic pyeloplasty with drainage using a double-J stent or a TEUS stent. Before the operation, patients underwent intravenous urogram (IVU) or retrograde urethrography, whichever was suitable for the diagnosis of UPJO. Group A and B patients were operated on by surgeons A and B, respectively, both of whom were associate chief physicians and had similar experiences. The included patients were divided into group A (double-J stent) or B (TEUS) mainly depending on who was the first clinical reception in outpatient, only one patient who was anxious of re-anesthesia choose “TEUS” operated by doctor B which was first reception by doctor A in outpatient.
2.3 Surgical techniques
The procedure of laparoscopic pyeloplasty was performed as reported previously, with minor modification. In group A, the double-J stent was be placed in an antegrade fashion via a trocar, and the perimeter of the double-J stent is 5 Fr. If the double-J stent insertion failed due to suspicion of ureterovesical junction obstruction, we used a nephrostomy tube through the renal pelvis. In group B, children were placed in the lithotomy position initially. A Fr3 or Fr4 (Fig. 2) stent was inserted in a retrograde fashion into the ureter via cystoscopy, with a Foley catheter placed in the bladder. During the process for laparoscopic pyeloplasty, we tried to incise the expanded pelvis and the abnormal ureter to achieve pelvo-ureteral anastomosis; the externalized stent could be tracked sequentially from the pelvis to the upper ureter afterwards. After pelvo-ureteral anastomosis, we ensured the proper positioning of the externalized stent for drainage and avoided dislocation. If the externalized stent dislocated and fail to drainage, we had to choose alternative diversion routes.
A perinephric drain was used for some children based on the operators opinion and whether there was exudate near the insertion area in both groups. If there was exudate in the operation area, ureteroedema in operation and a history of flank pain or urinary tract infection may exacerbate obstruction issues, a perinephric drain was used. Foley catheters were left in all patients immediately after the operation and were removed on the third day after operation in group A and at the time that the urethral stent was removed in group B. All patients received prophylactic antibiotic treatment until stent removal.
2.4 Outcome parameters
The outcomes of this study included stent-related complications: urine leakage, stent dislocation, stent occlusion, urinary tract infection, the severity of complications according to the Clavien–Dindo Classification system, and other surgery-related parameters including reoperation of pyeloplasty, hospitalization duration, and operation time. Urinary tract infection was defined based on the identification of pathogenic bacteria in urine culture in combination with pain, fever, and pyuria. All patients received a follow-up renal ultrasound in postoperative months 3, 6, and 12 month (for at least 12 months) and then every year (if longer than 12 months). We considered the operation successful based on symptom relief, improvement of hydronephrosis on renal ultrasound, or the avoidance of reoperation pyeloplasty.
2.5 Statistical analysis
All analyses were performed using SAS 9.0. The normalcy of distributed data was checked by a Kolmogorov–Smirnov test. Qualitative or categorical variables were expressed as frequencies and proportions and compared using the χ2 or Fisher exact test as appropriate. Data that did not comply with a normal distribution were expressed as median range and compared between groups using the Mann–Whitney test. All statistical tests were two-sided and performed with a significance level set at P < .05.
There were no significant differences between groups A and B with regard to preoperative data including age, sex, and the side and the mode of presentation (Table 1). Children were most commonly first diagnosed during pregnancy in both groups, and the median age at their operation was 46 months. The second most common factor for diagnosis was backache, and the median age at operation among these patients was 70.7 months.
The duration of operation was significantly longer in group B than in group A. Similarly, the median length of hospital stay in group B was 7.0 days (5–14 days), which was significantly longer than that in group A. However, this difference disappeared when we shortened the time of stent removal to 5 days in the last 15 patients (P > .05).
The anterior-posterior renal pelvic diameter (APRPD) was significantly improved after operation in both groups. Also, no significant difference in the severity of APRPD was observed between the groups preoperatively or postoperatively. None of the patients required repeat pyeloplasty.
The numbers of post-operative complications are summarized in Table 2. There were no significant differences in the complication rates between the 2 groups. None of these patients had urine leakage. Temporary stent occlusion was more common in group B patients, necessitating tube flushing to relieve symptoms. This was mainly attributed to the smaller size of the holes of the stent. However, total stent occlusion occurred in 2 children in group A, requiring placement of another stent for drainage. In group A, 5 children had a urinary tract infection while the double-J stent was in situ, and 2 of these 5 patients underwent stent re-insertion to drain the renal pelvis.
Four patients required re-operation in group A due to complications, including urinary tract infection and total stent occlusion. Two children with a urinary tract infection were not managed solely by antimicrobial therapy but were additionally treated with a retrograde ureteric stent to drain pyeuria. In group B, only one child had a urinary tract infection, and the externalized stent was flushed effectively.
Both groups A and B had 1 child for whom the drainage route was changed during operation. In the group A patient, the double-J stent could not cross the vesicoureteral junction, and thus, an external trans-renal pelvic stent was used. In the group B patient, the TEUS dislocated during patient repositioning, and another urine diversion route was used.
Clavien III complications occurred in 4 and 0 children in groups A and B, respectively, and these incidences were not significantly different.
In summary, complications related to stent implantation occurred in 10 and 8 children in groups A and B, respectively (P > .05).
In this study, we devised a novel external urine drainage approach that could be effective for pediatric patients with congenital UPJO. To our knowledge, we are the first to apply this technique in pediatric laparoscopy pyeloplasty.
Temporary stent occlusion occurred more frequently in group B for dysfunctional stents related to a narrow lumen and only 2 holes for drainage. Effective flushing is very important in these patients, David A reported 33.3% of their patients experienced intermitted poor drainage with externalized stent, and effective flushing resolved the problem. In our experience, temporary stent occlusion occurred mainly in the early stage when we began utilizing the TEUS, due to less frequent flushing of the externalized stent. After we identified this drawback, we used sodium chloride solution to flush the external stent twice a day, aseptic technique principle is important in this procedure, for urinary tract infection may exacerbate the renal function. It is important to perform postoperative flushing of the externalized stent, especially during the first 3 days after operation, and stent occlusion rarely occurs if postoperative flushing is regularly carried out. Effecting flushing is an important advantage in externalized stent,
Other types of externalized stents had been attempted in laparoscopic pyeloplasty, most of them adopt trans-pelvic route. Compared with double-J stents, externalized stents had fewer complications and fewer re-operation patients[8,15,16] (Table 3). But urine leakage around the tube and patient discomfort surrounding the tube entry site could not be avoided, in TEUS, insertion through natural orifices with minimum tissue damage could avoid the disturbance. Similar to TEUS, stent dislocation should be concerned throughout the perioperative period in externalized stents. With improved experience, we could shorten the time to stent removal to 5 days in 15 children with fair recovery, compared with the reported time of stent removal in externalized stents,[8,15] we are the shortest 1 could reduce the risk of stent dislocation.
Kocvara, R reported that the operation time of trans-anastomotic externalized stent was significant longer than double-J stent, for uretero-pyelostomy was a more demanding and time-consuming procedure. Our study also indicates that the duration of operation in TEUS group was significantly longer than that double-J group. This is likely due to the extra need of retrograde urethral stenting in TEUS group. In addition, the hospitalization duration was longer in TEUS group due to a cultural issue in which parents were afraid of providing appropriate postoperative care related to the externalized drain at home
For young children, double-J stent insertion can be difficult due to the small diameter of the ureter, especially near the ureterovesical junction. Double-J stenting may lead to local edema or injury to the inner wall of the ureter, resulting in a vulnerability to obstruction and malfunction.[4,17] Christoph Zoeller reported that the most common technical problem in the double-J group was inability to place the double-J catheter, nearly 19% of the double-J group. In contrast to these disadvantages of double-J stents, an externalized stent inserted in a retrograde fashion across the ureterovesical junction can diminish the injury to the ureter. Even though the narrow lumen of the externalized stent can still be a problem, efficient flushing can decrease the adverse influence of the narrow lumen.
The disadvantage of a double-J stent additionally includes the requirement of re-operation to remove the stent, especially in infants, and re-operation undoubtedly increases the cost compared with the use of an externalized stent. Yucel and colleagues performed in-office stent removal and avoided re-operation based on a dangler left in the double-J stent. Compared with the TEUS, their stent could not be flushed effectively during stent obstruction or urinary tract infection, thereby leaving the patients with the sensation of urgency due to retention of fluid in the stent, and 30% of the patients experienced flank pain and required re-stenting. Furthermore, the median age of their study participants was 11.3 years, and whether this procedure is appropriate for infants is still unknown. David reported a retrograde percutaneous access for kidney internal splint stent catheter to avoid stent removal in the operating room, similar to our experience, 33.3% of the patients had problems with intermittently poor drainage necessitating flushing, and the mean age was 8 years, the experience in younger patients was limited. In TEUS group, all children were able to avoid reoperation for stent removal, and the youngest 1 is only 8 months. This can be an important advantage in light of the known potential neurotoxicity of anesthesia, in addition to resource conservation involving operation room allocations.
The advantages of the trans-uretero-cystic externalized urethral stent according to this study include the ease of stent removal during ward care without the need for reoperation, insertion through natural orifices with minimum tissue damage, and symptom-directed stent occlusion or urinary tract infection management such as vomiting, backache, fever or abnormal urinalysis results. Flushing is indicated in these scenarios to relieve the obstruction or urinary tract infection. In the hand of an inexperienced surgeon, an artificial hydronephrosis could occur if the stent is clamped tightly; the new procedure we devised in this study can assist surgeons in finding the dilated pelvis more easily, especially when in patients who have had only mild hydronephrosis. This external-stent can also avoid the occurrence of artificial vesicoureteric reflux and diminish the risk of urinary tract infection. Finally, compared with using a double-J stent, our procedure is associated with a shorter duration of receiving prophylactic antibiotics among treated children. Nonetheless, disadvantages of this trans-uretero-cystic externalized urethral stent still exist. First, poor drainage capacity could appear, which was attributed to stent dysfunction necessitating light flushing to relieve transient obstruction. In addition, stent dislocation should be monitored throughout the peri-operative period and requires stent re-insertion if identified. Finally, with the external stent in situ, bed rest were mandated for all patients.
In this study, we present a new approach for urine diversion after pyeloplasty, that provided an equivalent outcome compared to the use of a double-J stent. Although the operation duration may be longer using this procedure, the avoidance of prolonged prophylactic antibiotics use and reoperation can be advantageous in infants and young children. However, a retrospective analysis and lack of randomization were the limitations of the study.
Data analysis: Jun-Jun Dong, Tao Lin.
Data collection: Jun-Jun Dong, Sheng Wen, Xing Liu, Feng Liu, Guang-Hui.
Manuscript writing: Jun-Jun Dong.
Project development: Feng Liu, Guang-Hui Wei.
. Cundy TP, Harling L, Hughes-Hallett A, et al. Meta-analysis of robot-assisted vs conventional laparoscopic and open pyeloplasty in children. BJU Int 2014;114:582–94.
. Gatti JM, Amstutz SP, Bowlin PR, et al. Laparoscopic vs open pyeloplasty in children: results of a randomized, prospective. Control Trial J Urol 2017;197:792–7.
. Mei H, Pu J, Yang C, et al. Laparoscopic versus open pyeloplasty for ureteropelvic junction obstruction in children: a systematic review and meta-analysis. J Endourol 2011;25:727–36.
. Elmalik KC, Capps MMSN. Ureteric stents in pyeloplasty: a help or a hindrance? J Pediatr Urol 2008;4:275–9.
. Yeung CK, Tam YH, Sihoe JD, et al. Retroperitoneoscopic dismembered pyeloplasty for pelvi-ureteric junction obstruction in infants and children. BJU Int 2001;87:509–13.
. Godley MLRP. Vesicoureteral reflux: pathophysiology and experimental studies. Pediat Urol 2010;283–300.
. Derderian CA, Szmuk P, Derderian CK. Behind the black box: the evidence for the U.S. Food and drug administration warning about the risk of general anesthesia in children younger than 3 years. Plastic Reconstructive Sur 2017;140:787–92.
. Helmy T, Blanc T, Paye-Jaouen A, et al. Preliminary experience with external ureteropelvic stent: alternative to double-j stent in laparoscopic pyeloplasty in children. J Urol 2011;185:1065–9.
. Lee LC, Kanaroglou N, Gleason JM, et al. Impact of drainage technique on pediatric pyeloplasty: comparative analysis of externalized uretero-pyelostomy versus double-J internal stents. Can Urol Assoc J 2015;9:E453–7.
. Bian Z, Liu X, Hua Y, et al. Laparoscopic management of multiple ureteral polyps in children. J Urol 2011;186:1444–9.
. Dindo D, Demartines N, Clavien P-A. Classification of surgical complications. Ann Sur 2004;240:205–13.
. Stein R, Dogan HS, Hoebeke P, et al. Urinary tract infections in children: EAU/ESPU guidelines. Eur Urol 2015;67:546–58.
. Hadley DA, Wicher C, Wallis MC. Retrograde percutaneous access for kidney internal splint stent catheter placement in pediatric laparoscopic pyeloplasty: avoiding stent removal in the operating room. J Endourol 2009;23:1991–4.
. Lucarelli G, Mancini V, Galleggiante V, et al. Emerging urinary markers of renal injury in obstructive nephropathy. Biomed Res Int 2014;1–7.
. Kocvara R, Sedlacek J, Drlik M, et al. Unstented laparoscopic pyeloplasty in young children (1-5 years old): a comparison with a repair using double-J stent or transanastomotic externalized stent. J Pediatr Urol 2014;10:1153–9.
. Zoeller C, Lacher M, Ure B, et al. Double-J or transrenal transanastomotic stent in laparoscopic pyeloplasty in infants and children: a comparative study and our technique. J Laparoendosc Adv Surg Tech A V 24 2014;205–9.
. Smith KE, Holmes N, Lieb JI, et al. Stented versus nonstented pediatric pyeloplasty: a modern series and review of the literature. J Urol 2002;168:1127–30.
. Braga LH, Lorenzo AJ, Farhat WA, et al. Outcome analysis and cost comparison between externalized pyeloureteral and standard stents in 470 consecutive open pyeloplasties. J Urol 2008;180:1693–8. discussion1698-1699.
. Yucel S, Samuelson ML, Nguyen MT, et al. Usefulness of short-term retrievable ureteral stent in pediatric laparoscopic pyeloplasty. J Urol V 177 2007;720–5. discussion 725.