Journal of Indian Association of Pediatric Surgeons
Journal of Indian Association of Pediatric Surgeons
                                                   Official journal of the Indian Association of Pediatric Surgeons                           
Year : 2018  |  Volume : 23  |  Issue : 4  |  Page : 186--191

A randomized control trial comparing outcome after stented and nonstented Anderson-Hynes dismembered pyeloplasty

Nilesh G Nagdeve1, Pravin D Bhingare2, Prashant Sarawade2,  
1 Department of Paediatric Surgery, Government Medical College, Nagpur, Maharashtra, India
2 Department of General Surgery, Government Medical College, Nagpur, Maharashtra, India

Correspondence Address:
Dr. Nilesh G Nagdeve
Plot No.: 19, Venuvan Society, Narendra Nagar, Nagpur - 440 030, Maharashtra


Aim: The aim of the study was to compare the efficacy and postoperative complications of stented and nonstented open pediatric dismembered pyeloplasty for ureteropelvic junction (UPJ) obstruction. Settings and Design: A balanced, parallel group, prospective randomized controlled trial comparing stented and nonstented Anderson-Hynes Dismembered Pyeloplasty. Subjects and Methods: It included 42 children who required Anderson-Hynes dismembered pyeloplasty for UPJ obstruction (UPJO). Patients were randomized into stented (double “J” [DJ] stent) and nonstented pyeloplasty groups. The intraoperative and postoperative course was compared. Both groups were analyzed for problems such as dysuria, frequency, pain, hematuria and urinary tract infection, and postoperative renal status. Statistical Analysis: Mann–Whitney U-test, Fisher's exact test, Student's t-tests, and Chi-squared test were used. Results: Surgical duration was significantly shorter for the nonstented group as compared to the stented group (60.4 ± 6.49 min vs. 78.9 ± 8.17 min). The intraoperative negotiation of DJ stent was troublesome in 21.7% patients belonging to the stented group. The hospital stay was comparable in both groups (4.67 ± 1.9 vs. 4.28 ± 0.67 days). Patients in stented group had experienced dysuria, loin pain, lower abdominal spasmodic pain, and frequency significantly higher than nonstented group. However, the other problems such as fever, hematuria, and urinary tract infections were more common in stented group, but the difference was not statistically significant. There was no difference in resolution of hydronephrosis in both groups. Conclusions: There is no statistically significant difference in resolution of hydronephrosis following nonstented or stented dismembered pyeloplasty in children with UPJO. However, the patient is more symptomatic due to stent in the postoperative period.

How to cite this article:
Nagdeve NG, Bhingare PD, Sarawade P. A randomized control trial comparing outcome after stented and nonstented Anderson-Hynes dismembered pyeloplasty.J Indian Assoc Pediatr Surg 2018;23:186-191

How to cite this URL:
Nagdeve NG, Bhingare PD, Sarawade P. A randomized control trial comparing outcome after stented and nonstented Anderson-Hynes dismembered pyeloplasty. J Indian Assoc Pediatr Surg [serial online] 2018 [cited 2021 Jun 24 ];23:186-191
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Although Anderson-Hynes dismembered pyeloplasty is nearly 70-year-old procedure, it is still considered as a gold standard for surgical correction of ureteropelvic junction obstruction (UPJO) due to its proven efficacy and a high success rate on long-term follow-up.[1],[2] A number of procedural modifications have been made, but the basic principles remained unchanged. One of the debatable aspects of the procedure is the role of urinary diversion after pyeloplasty.[3],[4],[5] Different types of drainage methods have been described in the literature including nephrostomy tube drainage, internal ureteral stents such as the double “J” (DJ) stent, external stent anastomosis, and a combination of these modalities. However, problems are associated with all types of drainage procedures. Nowadays, many surgeons tend to prefer internal drainage to external drainage.[3],[6] However, there is no reported evidence to date to support a clear advantage of either practice during pyeloplasty in terms of improvement in obstruction or reduction of postoperative morbidities.

With this background, we designed this study, randomized control trial, to compare the efficacy and postoperative complications of stented verses nonstented open pediatric pyeloplasty for UPJO.

 Subjects and Methods

A balanced, parallel group, prospective randomized controlled trial was performed over 3 years at our institute. Approval was obtained from the Institutional Ethical Committee before enrolling patients in the study (IRB No: 812/14). Patients were subsequently enrolled only after obtaining consent from the patient's legal guardian.


The study population consisted of patients younger than 12 years who required Anderson-Hynes dismembered pyeloplasty for UPJO. Patient with single kidney, secondary or recurrent UPJO, preoperative percutaneous nephrostomy or DJ stent, renal anomaly, and associated vesicoureteric reflex were excluded from the study. The diagnosis of UPJO was based on renal ultrasonography and obstructed pattern on diuretic nuclear renography (99m DTPA scan).


The subjects were randomized and allocated into two groups: Stented and nonstented. In stented group, DJ stent was kept across the anastomosis during pyeloplasty, while in nonstented group, nothing was kept across the anastomosis.

Sample size, assignment, and randomization

Power calculation was based on a study by Smith et al.,[6] wherein 88% of stented and 85% of nonstented patients had successful outcome following pyeloplasty. Establishing α at 0.05 and a power of 0.80 produced a sample size of 21 patients per arm. Sample size was calculated by nMaster 1.0 Sample size software developed by CMC, Vellore. A computer-generated random number table was used with equal allocation of subjects to the stented and nonstented groups.


The data were collected from these patients included demographic, clinical history, physical findings, detailed investigations, operative details, and postoperative findings. All the parents/guardians were informed regarding details of surgery, complications, postoperative care, and follow-up protocol. Patients were taken for surgery only after their urine cultures were negative.

Operative technique

The procedure was performed under general anesthesia. All patients underwent standard open Anderson-Hynes dismembered pyeloplasty through an anterior subcostal incision and an extraperitoneal approach. After standard exposure of the UPJ, a urine sample was taken for culture sensitivity. The obstructed segment of the ureter together with redundant portion of the renal pelvis was excised, and the ureter was spatulated on its lateral aspect to a distance of 0.5–1 cm. The patency of the distal part of the ureter was checked by passing a 5–6 Fr feeding tube distally. When the feeding tube could not be negotiated across the UVJ in nonstented group, a multihole transanastomotic feeding tube was kept as a stent and nephrostomy. Such patients were excluded from analysis. In stented group, with such problem, cystoscopy assistance was sought for DJ placement prior considering multihole transanastomotic tube. The anastomosis was accomplished using polyglactin 6/0 interrupted sutures, while renal pelvic closure was done by polyglactin 5-0. After closing the posterior layer of the ureter with the pelvis, a DJ stent was passed in stented group, whereas no stent was left in other groups. Thereafter, the anterior layer was closed.

Postoperative follow-up

Injectable antibiotics were continued for 48 h, and analgesia was given as required. Patients were observed for fever, pain, and swelling at operation site, urinary tract infection, acceptability, of oral food and ambulation. Parents/patients were asked about main complaints that are known to occur after pyeloplasty, i.e., dysuria, frequency, pain, and hematuria during the postoperative period. Crying during micturition in infants and younger children was considered as dysuria, while pain in loin was asked only in older children. Temperature more than 100° F was considered as statistically significant.

The patients were discharged on the 4th postoperative day if postoperative period was uneventful. At discharge, they were prescribed oral antibiotics and syrup/tablet paracetamol 15 mg/kg/dose only if necessary on the subsequent days. Parents were told to write down how many times they gave medicine for pain each day. Patients were followed up a week after the discharge, on 15th postoperative day and then at 3 months or if they had any problems. At first follow-up, renal sonography was done to note any collection in perinephric region and urine culture sensitivity was done in symptomatic patients. Stent was removed on 15th day under short general anesthesia as a day-care procedure. Uroprophylaxis was given for 21 days in both groups. At 3-month follow-up, urine culture and sensitivity, renal ultrasound, and nuclear diuretic renogram were repeated.

Statistical analysis

Continuous variables that were not normally distributed (e.g., age) were compared using the Mann–Whitney U-test, while others were compared using Student's t-tests. Categorical variables such as complications were compared using the Chi-squared test. For small numbers, Fisher's exact test was used. All tests were two sided and P > 0.05 was considered statistically significant. Statistical analysis was performed using Stata Software version 10.0 (Stata Corp, Texas, USA).


Out of 21 patients randomized to each group, one patient from the nonstented group who was lost to follow-up and two patients from the stented group (in one patient, stent could not be negotiated and the other patient lost to follow-up) were excluded from the final analysis. The two groups were comparable with respect to age, gender, laterality, presentation, blood investigations, renal functions, and diuretic renogram findings [Table 1]. The youngest age at which a patient was operated was 2 months. Preoperative urine cultures were positive only in five patients (Escherichia coli 3 and Klebsiella 2). Surgical duration was significantly shorter for the nonstented group as compared to the stented group (60.4 ± 6.49 min vs. 78.9 ± 8.17 min; Mann–Whitney U-test: The U-value is 6; Z-score is −5.23419; P < 0.05). The intraoperative negotiation of DJ stent was troublesome in 21.7% patients belonging to the stented group. Two of these required cystoscopic help for DJ stent placement, and in one patient, stent could not be negotiated. In this patient, a multihole transanastomotic tube was kept as stent and nephrostomy. Follow-up nephrostogram on the 8th postoperative day did not reveal any UPJO in this patient.{Table 1}

Postoperative follow-up

The hospital stay in the nonstented group was 4–12 days (mean: 4.67 ± 1.9) compared to 4–10 days (mean: 4.28 ± 0.67) in the stented group (The Z-score is −0.03773 and P = 0.9681; not significant). In both groups, the postoperative hospital stay was comparable in both infants and older children. However, one patient from stented group required the second admission for the complications. [Table 2] shows the comparative assessment of hospital stay, analgesic requirement (number of doses), and surgical duration in stented and nonstented group in infants and in older children.{Table 2}

Dysuria, pain in loin during voiding, frequency, fever, and hematuria were the prominent problems noted mainly in stented group. Dysuria, loin pain, lower abdominal spasmodic pain, and frequency were significantly higher in stented than nonstented group. However, the other problems such as fever, hematuria, and urinary tract infections though were more frequent in the stented group; the difference was not statistically significant. Details of the problems noted during follow-up are given in [Table 3]. Furthermore, the children in the stented group used analgesics significantly more than those in the nonstented group (7.71 ± 1.59 days vs. 3.45 ± 1.39 days, hazard ratio: 3.68; 95% confidence interval: 1.47–9.21; P = 0.0053). Nearly 42% of patients in stented group additionally required bladder relaxant for lower abdominal spasmodic pain.{Table 3}


One patient in nonstented group had local pain and fever on the 4th postoperative day. On USG, he was found to have a urinoma of volume approximately 30 cc. He required cystoscopic placement of DJ stent. He improved after that and discharged on the 12th day. One patient in the stented group had a major complication. In this patient, the stent was found to be present in renal pelvis and ureter with urinoma formation which required re-exploration, small incision over renal pelvis for removal of stent (under C-arm guidance), and placement of nephrostomy.

At 3-month follow up

The postoperative renal status of both groups was compared with their preoperative hydronephrosis by measuring renal pelvic anteroposterior diameter and findings of diuretic renogram. In the nonstented group, the preoperative and postoperative pelvic AP diameter was 35.14 ± 8.54 mm and 25.19 ± 2.53 mm, respectively (P < 0.001). In the ureteral stented group, the mean preoperative and postoperative pelvic AP diameter was 36.42 ± 6.48 mm and 25.60 ± 1.98 mm, respectively (P < 0.001). In the nonstented group, the differential renal function changed from 28.71% ± 5.5% to 30.8% ± 3.6% postoperatively, and improvement of diuretic obstruction was seen in 16 of 20 kidneys (80%) at 3-month follow up. In the stented group, the mean differential renal function changed from 30.41% ± 6.5% to 32.78% ± 5.42%, and improvement of diuretic obstruction was seen in 15 of 19 kidneys (78.94%). No patient in both groups experienced any episodes of urinary tract infections after 15th day follow–up; however, urine culture was positive for E. coli in one patient from each group.


Our study addresses the postoperative problems faced by the patients after pyeloplasty. Most of these patients are discharged early after surgery, and the parents remain apprehensive about the symptoms of their kids in postoperative period. One of the important goals of modern surgical practice is minimization of intervention with maximization of results with emphasis on early discharge and problem-free postoperative period. The present study corroborates with other pediatric pyeloplasty series that the stent-less pyeloplasty is better alternative to stented pyeloplasty in terms of problem-free postoperative period with equally good renal outcome.

Even the initial description of Anderson-Hynes dismembered pyeloplasty was as a stentless procedure.[1] Over the years, as operative techniques have evolved, concerns regarding prolonged urinary leak, risk of impaired postoperative antegrade flow due to edema, and need for secondary procedures have supported the use of various drainage techniques following pyeloplasty.[4] Problems are associated with all types of drainage procedures, i.e., both internal and external, still the internal stents remained popular. Several favorable reports of the use of internal stents have been published in recent years showing their advantages.[7],[8] The advantages of internal stents (DJ stent) compared to external stents include a shorter hospital stay and a lower morbidity rate. Furthermore, DJ stents supposed to prevent adhesion to the suture site by splitting the suture line, help to maintain an appropriate diameter and alignment of the ureter, and limit ureter kinking.

DJ stents are not free from problems. Disadvantages include difficulty in negotiating the wire or stent across the UVJ and deployment in the distal ureter when placed in an antegrade fashion. Furthermore, there is a need of a second anesthetic for removal in children. The DJ stent insertion, especially in small children, is a difficult task.[7],[9] Cystoscopic guidance may be needed for insertion of DJ stent.[10] However, the important problems patient faces after DJ stents' placement are lower urinary tract symptoms, due to mechanical irritation of the bladder trigone and loin pain due to retrograde passage of urine in renal pelvis during micturition. These symptoms are very troublesome and may warrant early stent removal.[9] McMullin noticed urinary urgency in 11.1% of patients, whereas Braga noted bladder spasm symptoms in 2.9% of his patients. Some authors have reported intermittent hematuria and mild pelvic discomfort until removal of stent.[11],[12] Our study focuses this important aspect of DJ stent after pyeloplasty. Dysuria, loin pain during micturition, lower abdominal spasmodic pain, and frequency were significantly higher in stented group compared to nonstented group. This resulted in the increased use of analgesic and the need to start antispasmodics. Concerns are shown about high incidence of hematuria and urinary tract infections after stented pyeloplasty. Smith et al. reported 6% patients with urinary tract infection in stented group versus 2% in nonstented.[6] We too found more patients with hematuria and urinary tract infection in stented group than in nonstented group. However, the difference was not statistically significant. In our study, cystoscopic assistance for DJ placement was required in two patients, while in one, the DJ placement was abandoned as we were unable to place the DJ stent across the vesicoureteric junction. As well, one of our patients in stented group had major complications. Major complications such as improper placement, migration of DJ stents, urinary tract infections, and urinoma formation have been known to occur in 2.5%–16.6% cases.[4],[9],[10] Various authors have reported the migration of DJ stent in pediatric patients requiring either replacement or removal.[12],[13] Urinary leak with urinoma formation was noted in only one patient in nonstented group.

There are many studies which have compared the outcome following stented and nonstented pyeloplasty.[3],[4],[6],[14],[15],[16],[17] Most of these pediatric pyeloplasty series have not observed any significant difference on improvement in hydronephrosis after stented pyeloplasty compared to nonstented group. We too found no significant difference between the nonstented group and the stented group in terms of improvement of hydronephrosis. Furthermore, a study of 224 pediatric pyeloplasties by Sutherland concluded that nonintubated, dismembered pyeloplasty is an excellent technique for all age groups and has a low complication.[17] Recently, robotic stent-less pediatric pyeloplasty has been reported with excellent success rates and minimal complications.[18] Therefore, we feel that the role of transanastomotic drainage after pyeloplasty in children is controversial. However, the smaller follow-up period and single institutional experience are the main limitations of this study. Hence, a prospective multi-institutional study with a long-term follow up is necessary to enhance the validity of this study in the future.


There is no statistically significant difference in resolution of hydronephrosis following nonstented or stented dismembered pyeloplasty in children with UPJO. However, the patients are more symptomatic due to stent in postoperative period. Therefore, we feel that keeping internal ureteral stent during pyeloplasty is not necessary; nevertheless, the use of internal ureteral stent for postoperative drainage should be made by surgeon's experience and preference.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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