Relative Contraindication to Endoscopic Subureteral Injection for Vesicoureteral Reflux: Congenital Refluxing Megaureter with Distal Aperistaltic Segment

Advancements in Surgical Management of Megaureters

PURPOSE OF REVIEW

To review and describe the recent evolution of surgery for the various types of pediatric megaureter.

RECENT FINDINGS

Megaureter management first relies on determining the underlying cause, whether by obstruction, reflux, or a combination, and then setting appropriate surgical indications because many cases do not require surgery as shown by observation studies. Endoscopic balloon dilation has been on the rise as a major treatment option for obstructive megaureter, while refluxing megaureters can also be treated by laparoscopic and robotic techniques, whether extravesically or transvesicoscopically. During ureteral reimplantation, tapering is sometimes necessary to address the enlarged ureter, but there are also considerations for not tapering or for tapering alternatives. Endoscopic and minimally invasive surgeries for megaureter have been the predominant focus of recent megaureter literature. These techniques still need collaborative prospective studies to better define which surgeries are best for patients needing megaureter interventions.

Evaluation of renal oxygenation by near-infrared spectroscopy during endoscopic injection of bulking agents in children with vesicoureteral reflux

BACKGROUND

Near infrared spectroscopy (NIRS) is the measuring of regional tissue oxygenation (rSO2) by interpreting oxyhemoglobin and deoxyhemoglobin signals that come back by transmitting near infrared light to tissues. The effect of endourological interventions on renal perfusion in children is largely unknown.

AIMS

To evaluate the effects of endoscopic injection of bulking agents (EIBA) for vesicoureteral reflux (VUR) on renal oxygenation (RO) using renal NIRS monitoring, which shows renal perfusion and oxygenation changes.

STUDY DESIGN

Case-control study.

METHODS

Group I had bilateral inguinal surgery, Group II cystoscopy, and Group III, EIBA for VUR with 30 patients in each group. During the operation, vital signs, peripheral oxygen saturation, end-tidal carbon dioxide, and renal regional oxygen saturation index (rSO2) values by bilateral renal NIRS monitoring were recorded. NIRS values before induction (T0) to postoperative (Tend) were determined. A 20% or more reduction in renal rSO2 (%20↓rSO2) was considered significant. Group III was also evaluated as subgroup III-A (not having "%20↓rSO2") and subgroup III-B ("%20↓rSO2").

RESULTS

The rSO2 decrease was observed in the first 5 min for both sides in group III. The most significant drop was at T30 for the right kidney and a significant decrease in rSO2, 20% or more, was observed in 6 renal units of 4 patients having higher SFU grading and renal scar in group III.

CONCLUSION

EIBA may transitionally impair renal oxygenation. Higher SFU grading and renal scar may increase the risk of renal hypoxia during EIBA.

Endoscopic Correction of Reflux Utilizing Polyacrylate Polyalcohol Bulking Copolymer (Vantris) as a Tissue Augmenting Substance: Lessons Learned Over the 10 Years of Experience

Objectives: To prove the hypothesis that modifying the endoscopic correction of vesicoureteral reflux (VUR) technique (STING procedure) and sharpening its contraindications, lead to increased success rate and decline in the complication rate. Materials and Methods: All patients that underwent endoscopic correction of VUR utilizing Vantris were divided into two groups according to procedure date; before 2015 and 2015-2019. Indication for treatment included persistent high-grade VUR or breakthrough infections. Contraindications included voiding dysfunction, active infection and since 2015 suspicion for obstructive/refluxing ureterovesical junction (UVJ) presented by "beak" sign on voiding cystourethrography (VCUG). Follow-up regiment included ultrasound and VCUG at predetermined intervals. Results: The first group included 215 (158 girls and 57 boys) children with mean age of 4.8 ± 2.8 years who underwent endoscopic correction between 2009 and 2015 and the second group included 42 children (28 girls and 14 boys) with mean age of 3.9 ± 2.1 years who underwent surgery between 2015 and 2019. In the first group, VUR was unilateral in 74 patients and bilateral in 132 comprising 338 renal refluxing units. In the second group, VUR was unilateral in 14 patients and bilateral in 30 comprising 74 RRUs. In the first group reflux was corrected in 317 (94.9%) RRUs after a single injection, after the second in 7 (2.1%) RRUs. In seven (2.1%) RRUs, reflux downgraded to Grade I-II. Three RRUs (0.9%) failed endoscopic correction and required ureteral reimplantation. Nine (2.7%) RRUs developed UVJ obstruction. In the second group reflux was corrected in 61 (82.4%) RRUs after a single injection, after the second in 12 (16.2%) RRUs. In one (1.4%) RRU, endoscopic correction failed and required ureteral reimplantation. None of the patients developed UVJ obstruction. Reflux correction has led to the significant decrease of febrile urinary tract infection (UTI) in both groups. Conclusions: Our data indicate that endoscopic injection utilizing Vantris is safe and long durable procedure. Although utilizing the proper technique and contraindication criteria, the rates of post procedural VUJ obstruction is null.

What are the predictive factors leading to ureteral obstruction following endoscopic correction of VUR in the pediatric population?

BACKGROUND

It is extremely important to not only address the short-term success following endoscopic correction of vesicoureteral reflux (VUR) but also the long-term efficacy and safety of the tissue augmenting substance utilized for endoscopic correction.

OBJECTIVE

This study retrospectively evaluated all cases of ureterovesical junction (UVJ) obstruction following endoscopic treatment of VUR over the last 5 years utilizing two tissue augmenting substances, with special emphasis on the safety of Vantris^®, and performed clinical and histological review of these patients.

METHODS

The study population comprised 2495 patients who underwent endoscopic correction of VUR utilizing Deflux^® (1790) and Vantris^® (705). Tissue sections were stained with hematoxylin & eosin and trichrome, and examined under a light microscope. Nine primary obstructive megaureters after ureteral re-implantation served as controls.

RESULTS

Nine (0.5%) children (three female and six male) in the Deflux group and nine (1.3%) (five females and four males) in the Vantris group developed UVJ obstruction and required ureteral re-implantation. Obstruction developed during the period ranging 2-49 months (average 16 months) following endoscopic correction. The primary reflux grade was III in seven, IV in six, and V in six children. The mean volume of the injected material in all obstructed patients was 1.2 ± 0.6 cc (mean ± SD). Histopathological analysis revealed a pseudocapsule composed of fibrous tissue and foreign-body giant cells surrounding the Vantris implant in all patients. The distal part of the ureters demonstrated significant ureteral dilatation without ureteral fibrosis. In all patients, additional biopsies from the muscularis propria adjacent to the injection site were examined and showed no significant abnormalities. There was an increased collagen deposition in the juxtavesical segment of the obstructive ureters following Deflux and Vantris injections, and of primary obstructive megaureter. No significant difference was found in the tissue response between Deflux and Vantris patients and controls. Statistical analysis of the nonhomogeneous population demonstrated higher obstruction rates in patients from the Vantris group. However, no statistical difference was demonstrated regarding the obstruction rate in the homogenous group with relation to gender, age and reflux grade group of patients. Moreover, univariate analysis revealed that Grade V reflux, the presence of beak sign on the reviewed pretreatment, and inflamed bladder mucosa upon injection were significant independent risk factors leading to obstruction.

DISCUSSION

This study suggested that the underlining ureteral pathology lead to UVJ obstruction following Vantris injection. There was increased collagen deposition in the juxtavesical segment of the obstructive ureters following Vantris injection. Furthermore, these findings were similar to those discovered in patients who underwent endoscopic correction with Deflux, and in patients who required ureteral reimplantation due to primary obstructive megaureter. Additional biopsies from the muscularis propria adjacent to the injection site showed no significant abnormalities, ironing out the fact that Vantris did not led to adverse tissue reaction following injection. Univariate analysis further ironed out the hypothesis that underlying ureteral pathology was responsible for the increased incidence of UVJ obstruction and demonstrated that Grade V reflux, the presence of beak sign on the reviewed pretreatment VCUG, and inflamed bladder mucosa upon injection were significant independent risk factors leading to obstruction.

CONCLUSION

Data showed that Vantris injection did not lead to any different ureteral fibrosis or inflammatory changes to the tissue augmenting substances utilized in past and present clinical practice, and therefore did not seem to increase the incidence of UVJ obstruction. High reflux grade, presence of obstructive/refluxing megaureter and inflamed bladder mucosa were the only statistically significant and independent predictive factors for UVJ obstruction following endoscopic correction of VUR.

Changing bulking agent may require change in injection volume for endoscopic treatment of vesicoureteral reflux

Introduction:

Various bulking agents were utilized for endoscopic correction of VUR. A study reviewing multi-institutional data showed that the amount of injection material has increased over time with the purpose of improving success rates, which also resulted in costs. We noticed an opposite trend in our center since we started using a new bulking agent. The aim of this study was to evaluate evolution of our practice with different bulking agents.

Patients and Methods:

Records of VUR patients who underwent subureteric injection with polyacrylate polyalcohol copolymer (PPC) and dextronomere hyaluronic acide (DxHA) between 2005 and 2014 were reviewed. Variation of different parameters throughout the study period was evaluated along with the success rate. Success was defined as complete resolution of reflux.

Results:

A total of 260 patients with 384 refluxing units were included. The success rate was higher in PPC group compared to DxHA group. There was no statistically significant difference between years regarding distribution of VUR grade, body weight, patient height, and age in PPC group. Despite significant reduction in injection volume, success rate did not decrease through the years with PPC.

Conclusion:

Different bulking agents may require different injection volumes to achieve the same success rate in endoscopic treatment of vesicoureteral reflux. Habits gained with previous experience using other materials should be revised while using a new agent.

Endoscopic correction of vesicoureteral reflux in children with a solitary kidney: the risk of obstruction

PURPOSE

We aimed to review patients with a solitary kidney and ipsilateral vesicoureteral reflux (VUR) who underwent endoscopic correction of VUR (ECVUR) and to evaluate the prevalence of obstruction in this group of patients.

MATERIALS AND METHODS

We retrospectively reviewed the files of all patients who underwent ECVUR at our center between January 2000 and June 2011. Only patients with a solitary kidney and ipsilateral VUR were included.

RESULTS

Thirteen patients met our criteria. Two patients (15.38%) developed obstruction post-ECVUR. Both patients developed anuria in the first 24 h after surgery and required intervention. Two patients (15.38%) had increasing hydroureteronephrosis that was discovered on follow-up ultrasound, with no symptoms or signs of obstruction. Both were managed conservatively.

CONCLUSION

Our results showed a higher percentage of obstruction post-ECVUR in patients with a solitary kidney (15.38%), who required immediate intervention. Thus, we recommend giving clear instructions to parents of patients with VUR and a solitary kidney post-ECVUR before discharge from the hospital regarding decreased urine output and loin pain. We recommend a follow-up ultrasound to rule out obstruction and detect new-onset hydronephrosis.

Acute and delayed vesicoureteral obstruction after endoscopic treatment of primary vesicoureteral reflux with dextranomer/hyaluronic acid copolymer: why and how to manage

OBJECTIVE

To present our cases of ureteral obstruction after endoscopic treatment of vesicoureteral reflux (VUR) with dextranomer/hyaluronic acid (Dx/HA).

PATIENTS AND METHODS

We collected data from patients who had suffered ureteral obstruction after endoscopic treatment of VUR with Dx/HA in our institution.

RESULTS

From April 2002 to April 2011 we treated endoscopically 475 ureters with VUR, and detected 5 ureteral obstructions. Median age at reflux treatment was 39 months. Reflux grade before treatment was III in one patient and IV in four. Three ureterovesical junctions (UVJ) were blocked after a second endoscopic treatment. The median of Dx/HA injected was 1 ml (0.6-1.1). In two patients ureteral obstruction presented acutely and was treated with a ureteral stent. In the other three, the ureteral obstruction appeared gradually and was detected by ultrasound scans and MAG3 diuretic renogram; one underwent nephrectomy because of poor renal function, and the other two were treated with endoscopic dilatation of the UVJ. In all these patients both reflux and obstructions have resolved.

CONCLUSIONS

On preoperative cystography, three of the patients had a narrowed distal ureter, and probably had a refluxing and obstructive megaureter. Other causes are not clear, except for those patients with acute presentation in whom edema of the UVJ was found. Ureteral obstruction after endoscopic treatment of VUR is rare. Endoscopic intervention such as ureteral stent placement or high-pressure balloon dilatation of the UVJ has good results as a treatment of acute and delayed obstruction.