Laparoscopic robotic takedown ureterostomy with extravesical cross-trigonal reimplantation after end cutaneous ureterostomy

Abstract

Introduction

The main goal of managing an obstructed megaureter (OMU) is to preserve the function of the affected kidney. To preserve the upper urinary tract, end cutaneous ureterostomy (ECU) seems to be a promising temporizing option. We aimed to evaluate our experience with ECU in patients with primary and secondary OMU and to demonstrate an efficacy of robot-assisted laparoscopic takedown ureterostomy and subsequent extravesical ureteric reimplantation.

Materials and methods

Retrospective analysis of patients that underwent ECU due to primary or secondary megaureter between 2003 and 2020. Nineteen patients (12 males, 7 females) with a mean age of 4.2 ± 3.5 months (mean ± standard deviation) underwent ECU of 27 renal units. Of those, 11 (57.9%) had primary OMU and 8 (42.1%) had secondary OMU. Undiversion was performed in 16 (84%) out of 19 patients (20 renal units out of 27 [74%]).

Results

In the vast majority of the cases, we have observed improvement in the hydronephrosis and renal function after ureterostomy. After reimplantation ultrasonography showed either stable or further improvement in hydronephrosis in 80% of patients. Robot-assisted laparoscopic patients had shorter admission period and indwelling catheter time after the surgery.

Conclusions

End cutaneous ureterostomy is a safe and effective temporary procedure for the treatment of progressive primary and secondary megaureters. Robot-assisted laparoscopic takedown of ureterostomy with subsequent reimplantation seems to be a good alternative for undiversion and subsequent reimplantation in these patients.

1. Introduction

The main goal of managing an obstructed megaureter (OMU) is to preserve the function of the affected kidney. Several treatment options exist, particularly for young children.^[1] Ureteric reimplantation can be technically challenging in small infants. In such cases, end cutaneous ureterostomy (ECU) seems a promising temporarily option for upper urinary tract preservation.^[2] There are different approaches to ureteral reimplantation during follow-up to restore the normal anatomy of the renal tract. Robot-assisted laparoscopic (RAL) surgery is a safe and minimally invasive technique that has become more widely used in pediatric urology over the last decade. Robotic surgery is particularly well suited to reconstructive surgery involving delicate structures, such as the ureter.^[3,4] We recently demonstrated that our laparoscopic robot-assisted reimplantation technique achieved the same results as open reimplantation and the benefits of a minimally invasive approach.^[5] This study had 2 objectives. First, we evaluated our experience treating ECU in patients with primary and secondary OMU and demonstrated the efficacy of laparoscopic robot-assisted takedown ureterostomy and subsequent extravesical ureteral reimplantation.

2. Materials and methods

Upon receiving ethical committee approval, we performed a retrospective analysis of the medical records of all patients who underwent ECU for primary and secondary megaureter in 2003 to 2020. We reviewed the medical history, surgical data, ultrasonography (US) results, renal scans, and blood samples. All patients who were treated under the same protocol for managing OMU and supervised by the senior author were included. Ultrasonography was performed on Day 3 of life among children with an antenatal diagnosis of hydronephrosis to confirm the prenatal diagnosis, with repeat US used to grade hydronephrosis.

Mercaptuacetyltriglycine radionuclide studies were performed at 6 to 8 weeks of age. A (99 m) Tc-dimercaptosuccinic acid renal scan was performed in cases of suspected renal damage to assess relative renal function using background-corrected regions of interest in the posterior view of each kidney and calculate the resultant percentage uptake. The scan was performed at least 6 months after the last febrile urinary tract infection (UTI). Renal scintigraphy was performed 2 hours after the dimercaptosuccinic acid injection. The fractional left and right renal activities were calculated for each kidney. A kidney uptake of 40% to 50% of the total renal activity was considered normal. Relative renal function of 30% to 40% was considered moderate, whereas a relative renal function below 30% was considered poor. Voiding cystourethrography (VCUG) was performed to exclude vesicoureteral reflux (VUR). The frequency of further examinations was tailored to the findings of the initial studies. Hydronephrosis degree was assessed according to Society for Fetal Urology classification.^[6,7]

The indications for ECU were recurrent UTI, progressive dilation on US, or deterioration of renal function with an increase in serum creatinine level.^[8] In these patients, definitive treatment, such as ureteral reimplantation, was not an option due to severe ureteral dilatation and a small estimated bladder capacity that did not allow antireflux reimplantation.

All patients with secondary OMU were diagnosed with a posterior urethral valve (PUV) after the antenatal diagnosis. As part of the routine protocol in all patients with PUV, immediate decompression of the bladder was performed using a urethral catheter without a balloon accompanied by the commencement of oral oxybutynin therapy 0.4 mg/kg at 24 hours. If serum creatinine level continued to rise despite adequate bladder decompression, secondary obstruction of the ureterovesical junction (UVJ) due to detrusor thickness was suspected, and supravesical diversion was performed. In cases of bilateral ECU, the parents were taught to perform bladder cycling, and all patients were maintained on oxybutynin therapy until definitive treatment. These patients underwent an obligatory videourodynamic study upon ureterostomy takedown and ureteral reimplantation. The decision to perform takedown ureterostomy was made as part of follow-up when the child was mature enough to withstand surgery, was free of infection, and had a large estimated bladder capacity.

The open undiversion was initiated with a Pfannenstiel incision after the release of the ureter from the abdominal wall. Two stay stitches were placed in the bladder. The bladder was opened, and reimplantation was performed using the Cohen or Politano-Leadbetter technique. During RAL surgery, the undiversion RAL extravesical cross-trigonal ureteral reimplantation technique was performed as previously described.^[5] In brief, after docking of the XI robotic platform, an 8-mm umbilical camera trocar, two 8-mm robotic trocars, and 5-mm assistant trocars were placed. Through a small peritoneal window, bilateral takedown ureterostomies were performed using cold scissors. Two stay stitches were placed in the bladder. A careful and meticulous extravesical transverse detrusorotomy was performed, and a 5-cm submucosal tunnel was created. The bladder mucosa was opened on the contralateral side of the reimplanted ureter side of the tunnel, and ureterovesical anastomosis was preformed utilizing 5-0 Maxon interrupted sutures. The JJ stent was then inserted, and the anastomosis was completed. The same procedure was performed on the contralateral side in cases with bilateral pathology. The detrusor was closed utilizing a 4-0 V-Look running stick. The indwelling catheter was left in the bladder for 24 to 48 hours. Only 1 patient required ureteral tapering during undiversion and reimplantation. In all cases, stents were left indwelling for 4 to 6 weeks.^[9]

All patients underwent an US examination at 3 months after surgery. These patients, who demonstrated improvement in hydronephrosis, also underwent follow-up US at 6 months and 1 year after surgery. If the US did not demonstrate worsening of the hydronephrosis, we proceeded with the annual US. The VCUG examination was performed at 3 to 6 months postoperative. If US examination demonstrated worsening of the hydronephrosis, a dynamic mercaptuacetyltriglycine study with a urinary catheter in the bladder was performed to rule out a recurrent UVJ obstruction. In cases of suspected valve bladder, a repeated videourodynamic study was performed to rule out decompensated bladder, and further treatment was tailored according to the urodynamic findings. The follow-up after open reimplantation was the same. The mean total follow-up in this study was 67.3 ± 57.7 months.

Statistical analyses were conducted using SPSS version 20.0 (SPSS Inc., Chicago, IL). Continuous variables are expressed as mean ± standard deviation, whereas categorical variables are presented as absolute numbers and percentages. Statistical significance was set at p < 0.05. The Chi-square test was used to compare categorical variables between the 2 groups. For comparison of continuous variables between the 2 groups, the Student's t-test or the Mann-Whitney U test was used depending on whether the statistical hypotheses were fulfilled.

3. Results

A total of 19 patients (12 male, 7 female) with a mean age of 4.2 ± 3.5 months underwent ECU consisting of 27 renal units (RU). All patients were in their first year of life during the first operation with an average weight of 5.6 ± 2.2 kg. Of them, 11 (57.9%) had primary OMU and 8 (42.1%) had secondary OMU (Table 1). Four children (21%) had a duplex system: 2 on the left side and 2 on the right side.

Table 1.

Patients demographics and basic criteria.

Characteristics	Primary megaureter	Secondary megaureter	p	Total
Sex, n (%)			0.96
Male	7 (63.6)	5 (62.5)		12 (63.2)
Female	4 (36.4)	3 (37.5)		7 (36.8)
Age, mo	4.6 ± 2.7	3.7 ± 4.8	0.02	4.2 ± 3.5
Weight, kg	6.3 ± 1.8	4.3 ± 2.3	0.764	5.6 ± 2.2
Kidney units, n (%)			0
One	11 (100)	0 (0)		11 (57.9)
Two	0 (0)	8 (100)		8 (42.1)
Side, n (%)			0
Right	3 (27.3)	0 (0)		3 (15.8)
Left	8 (72.7)	0 (0)		8 (42.1)
Bilateral	0 (0)	8 (100)		8 (42.1)
Time to reimplantation, mo	16.5 ± 4.2	18.8 ± 13.3	0.08	17.4 ± 8.4
Reimplantation method, n (%)			0.88
Open	7 (70)	4 (66.7)		11 (68.8)
Robotic	3 (30)	2 (33.3)		5 (31.2)

Overall, 14 (74%) patients (9 [82%] in the primary OMU group, 5 [63%] in the secondary megaureter group) demonstrated improved hydronephrosis after ureterostomy. None of the patients showed worsening hydronephrosis. There were no incidences of stomal stenosis or prolapse. Five patients experienced febrile UTI after the procedure. The mean creatinine levels were 1.7 ± 1.8 mg/dL before ECU and 1.2 ± 1.3 mg/dL after ECU (p = 0.04).

Mean follow-up until undiversion and reimplantation was 17.4 ± 8.4 months (range, 8–44 months). The mean age at undiversion was 21.9 ± 7.2 months. Undiversion was performed in 16 (84%) of 19 patients (20 RU of 27 [74%]). Eleven (69%) patients (14 RU) underwent open reimplantation, and 5 (31%) underwent RAL reimplantation (6 RU). Robot-assisted laparoscopic patients had a shorter admission period and indwelling catheter time after surgery (1.5 ± 0.57 days vs. 4 ± 0 days, p = 0.03). Three patients did not undergo reimplantation: 1 (2 RU) waited to undergo undiversion and reimplantation due to her young age, and another patient (2 RU) required renal transplantation due to chronic renal failure. The third patient (1 RU) was scheduled for nephrectomy because of poor functioning of the operated kidney. In addition, 2 patients (1 RU each) underwent undiversion and reimplantation, but only on 1 side with simultaneous nephrectomy on the other side due to renal nonfunction.

After reimplantation, US showed stable or further improved hydronephrosis in 80% of patients. Voiding cystourethrography was performed in 7 children postoperatively. Some patients' parents denied VCUG because they showed improvement on US and the absence of febrile and nonfebrile UTI. Three patients (all from the open surgery group; 1 with PUV, and 2 with unilateral OMU) showed VUR (all Grade II) on postundiversion VCUG. Of those, 2 underwent successful endoscopic correction and 1 underwent nephrectomy because of renal nonfunction. After reimplantation, 5 patients had febrile UTI (4 underwent open reimplantation, whereas 1 underwent robotic reimplantation). All patients underwent VCUG, which did not reveal VUR.

4. Discussion

Ureteric reimplantation due to primary or secondary UVJ obstruction can be technically challenging in small infants. In such situations, diverted ECU seems a promising option for preserving the upper urinary tract.^[1,2] Other options include vesicostomy, loop ureterostomy, or temporary refluxing megaureter reimplantation.^[10]

Our data further support the efficacy of ECU in cases of primary or secondary OMU.^[1,2,11] In the vast majority of cases presented here, we observed improvement in hydronephrosis and renal function after ureterostomy. Because we observed significant improvement in hydronephrosis, only 1 patient required ureteral tapering during undiversion and reimplantation.

Two-thirds of our patients underwent open reimplantation, whereas the remaining (5 patients, 7 RU) underwent RAL reimplantation using the robotic-assisted laparoscopic dismembered extravesical cross-trigonal ureteral reimplantation technique. Two of these patients underwent bilateral reimplantation without any difference in recovery or length of hospitalization.^[12] None of the patients had urinary retention. In our experience, robotic-assisted laparoscopic dismembered extravesical cross-trigonal ureteral reimplantation allows a longer and wider tunnel in the detrusor that allows bilateral ureter reimplantation without ureteral tapering or a greater risk of uretero-ureteral fistula. In addition, extravesical dissection far from the bladder nerves in the dorsomedial part of the UVJ prevents the risk of acute urinary retention. Patients with RAL require significantly less postoperative analgesia and have a shorter admission period and indwelling catheter time after surgery.^[3,4] Our data also demonstrated that RAL patients had a shorter admission period and indwelling catheter time after surgery. Indeed, good RAL ureteral reimplantation results have been described in a number of studies.^[13–15] However, to the best of our knowledge, no group to date has shown the results of RAL takedown ureterostomy after ureter reimplantation. It is important to note that the more comfortable we felt during robotic procedures, the more we converted from open access to it. We believe that the first surgeon should gain experience in robotic surgery, such as pyeloplasty, and then continue to perform surgery, which is more complicated, as we previously published.^[16]

Most patients showed stable or further improved hydronephrosis after reimplantation. Two patients who demonstrated worsening hydronephrosis were conservatively followed up in the clinic. The patients have done well so far, with no UTI and no deterioration of renal function or further deterioration of hydronephrosis. The third patient has a valve bladder and is currently awaiting kidney transplantation.

Vesicoureteral reflux was demonstrated in 3 patients who underwent undiversion and VCUG. Kitchens et al.^[2] reported VUR in 5 of 21 patients. Four patients had a primary OMU. Lome and Williams reported VUR in 7 of 17 patients after reimplantation.^[17] They believe that the reason for the postprocedural reflux is the technical difficulties in reimplanting dilated thick-walled ureters. We believe that the main reason for residual recurrence in patients with PUV is abnormal bladder function, even though all patients were treated with aggressive anticholinergic therapy and monitored prospectively within our dysfunctional voiding program including videourodynamic follow-up and biofeedback therapy. In the case of primary OMU, we assume that VUR occurs due to ureteral dilatation and inadequate peristalsis.

Five patients (3 with primary OMU, 2 with secondary) developed febrile UTI after reimplantation. None of the patients showed reflux on the postoperative VCUG. The 3 children in the primary OMU group that suffered from UTI had a duplex system or ectopic ureter. All patients had renal scarring on the renal scan. It has been shown that congenital and acquired renal dysplasia increase the chances of developing a UTI.

This study is not without limitations worth mentioning. First, all patients were followed-up retrospectively. Second, this group of patients had primary and secondary OMU. However, we aimed to demonstrate the efficacy of ureteral diversion using ECU in a heterogeneous group of patients and present the benefits of RAL surgery in the treatment of these patients. Third, the number of patients was small, but the need for ureterostomy is also rare. Fourth, not all patients underwent a radionuclide study and VCUG postoperatively. However, all patients showed hydronephrosis improvement on US and were free of UTI. Moreover, all patients with febrile UTI had VCUG and demonstrated no VUR.

5. Conclusions

Our data showed that ECU is a safe and effective temporary procedure for the treatment of progressive primary and secondary megaureter. Robot-assisted laparoscopic takedown of ureterostomy with subsequent reimplantation appears to be a good alternative to undiversion and subsequent reimplantation in these patients.

Conflict of interest statement

The authors have no relevant financial or nonfinancial interests to disclose.