Histopathological Changes Associated With Dextranomer/Hyaluronic Acid Injection for Pediatric Vesicoureteral Reflux

The color Doppler twinkling artifact of implants after endoscopic treatment of vesicoureteral reflux in children: A common finding with high potential for misdiagnosis

BACKGROUND

Endoscopic treatment of vesicoureteral reflux (VUR) is a common therapeutic procedure in children. Over the last years several studies reported on calcified deflux implants that were misinterpreted as ureteral stones leading to unnecessary diagnostic and therapeutic procedures.

OBJECTIVE

Based on an own case, where a calcified implant with a strong twinkling artifact was misdiagnosed as a ureteral stone, the purpose of our study was to evaluate the sonographic imaging appearance of implants after endoscopic VUR repair with special emphasis on the color twinkling artifact.

MATERIAL AND METHODS

In 40 children (mean age 9.5 years) with 62 treated ureteral units follow-up sonography was performed after a mean time interval of 48.8 months after surgery. The injected deposit was evaluated with B-mode sonography and color Doppler sonography and deposit volume, posterior acoustic shadowing and the appearance and extension of the twinkling artifact were evaluated.

RESULTS

47 of 62 injected units (75.8%) could be identified on follow-up sonography. In 13 of 47 units (27.7%) posterior acoustic shadowing was noted. On color Doppler sonography a twinkling artifact appeared in 26 of the 47 visible cases (55.3%). There was a statistically significant correlation between a positive twinkling sign and the deposit age.

CONCLUSION

In conclusion our study shows that the twinkling artifact is a common finding in follow-up sonography of children after endoscopic treatment of VUR. As the twinkling artifact is a sensitive imaging sign for the detection of ureteral calculi the risk of misinterpretation and mistreatment is given.

Non-Animal Stabilized Hyaluronic Acid/Dextranomer Gel (NASHA/Dx, Deflux) for Endoscopic Treatment of Vesicoureteral Reflux: What Have We Learned Over the Last 20 Years?

Non-animal stabilized hyaluronic acid/dextranomer gel (Deflux; NASHA/Dx) was developed as a treatment for vesicoureteral reflux (VUR) in the 1990s. To mark 20 years since the US approval of this agent, we reviewed its properties, best practice for application, and the available clinical safety and efficacy data. Long-term or randomized, controlled studies of treatment with NASHA/Dx have reported VUR resolution rates of 59%-100% with low rates of febrile urinary tract infection post-treatment (4%-25%), indicating long-term protection of the kidneys. An individualized approach VUR management is advocated, and NASHA/Dx is a viable option for many patients requiring intervention.

Incidence and risk factors for calcification after dextranomer/hyaluronic acid (Dx/HA) copolymer injection for vesicoureteral reflux

INTRODUCTION

Since the first case of dextranomer/hyaluronic acid (Dx/HA) implant calcification in 2008, concern about the long-term sequelae of Dx/HA injection has been growing. According to previous reports, the incidence of Dx/HA calcification 4 years after injection would be around 2%.

AIM

The primary aim was to estimate the incidence of Dx/HA implant calcification after endoscopic treatment of vesicoureteral reflux in pediatric patients. Secondary objectives were to establish risk factors and to perform a survival analysis after Dx/HA injection.

STUDY DESIGN

Patients undergoing Dx/HA endoscopic injection from 2007 to 2014 were prospectively registered. The database included clinical, surgical and radiological outcomes. Patients that showed Dx/HA implant calcification during follow-up were compared to those who did not. Univariable and survival statistical analyses were performed.

RESULTS

30 implants calcified over 355 ureters endoscopically treated. Age at first treatment was lower in patients with implant calcification (2.4 ± 1.3 years vs 3.6 ± 2.5 years; p < 0.005). The risk of implant calcification was 8.45% (95% CI: 5.96-11.85%). Median follow-up was 7.6 years (IQR: 5.2-9.5). The incidence rate was 12.06 cases per 1000 ureters-year. The period of highest hazard of implant calcification was between 3 and 5 years after injection. The only risk factor related to implant calcification was the age at first injection: relative risk of implant calcification was 4.4 (95% CI: 1.6 to 12.4; p = 0.002) for patients first treated before the age of 3.5 years.

DISCUSSION

The risk and the incidence rate of Dx/HA implant calcification were higher than previous data. The period of highest hazard and detection of implant calcification were consistent with previous reports. Patients first treated before the age of 3.5 had shorter survival time without implant calcification. These are the first data about risk factors and survival function of Dx/HA implant calcification. However, our conclusions about the clinical significance of Dx/HA implant calcification were limited because the patients with implant calcification were asymptomatic. Further studies with larger sample and longer follow-up should confirm the clinical significance and life-long tendency of Dx/HA implant calcification.

CONCLUSIONS

The risk and the incidence rate of Dx/HA implant calcification were higher than expected. The hazard of calcification was higher between 3 and 5 years after injection. The risk was especially higher in patients treated before the age of 3.5. Caution should be taken not to confuse implant calcifications with ureteric stones. A 5-year follow-up would set a better understanding of the actual incidence and clinical significance of implant calcification.

Ultrasound-guided fine-needle aspiration of a rectal submucosal nodule

Although endoscopic biopsy of a rectal submucosal nodule may be nondiagnostic, endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) can be an important tool to make diagnosis. We report a case of a female patient who had an EUS-FNA of a submucosal nodule after a nondiagnostic rectal biopsy. The original diagnosis was erroneously rendered as concerning for necrotic neoplasm. The correct diagnosis of Solesta-induced foreign body reaction was made on reviewing the slides once the history of remote Solesta injection was made available. This case illustrates the pathognomonic features of Solesta-induced rectal nodule and underscores the importance of detailed history as well as inclusion of iatrogenic diseases in the differential to prevent erroneous diagnosis and management. Potential pitfalls in cytopathological diagnosis are discussed.

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.

Endoscopic, Ultrasonographic, and Histologic Descriptions of Dextranomer/Hyaluronic Acid in a Case of Fecal Incontinence

OBJECTIVE

To present a case of fecal incontinence treated with dextranomer/hyaluronic acid (Solesta®) injections, which later caused clinical confusion and avoidable interventions. The endoscopic, ultrasonographic, and histologic appearances of dextranomer/hyaluronic acid will also be reported.

CASE PRESENTATION

A middle-aged Hispanic male who failed conservative management of his fecal incontinence was injected with dextranomer/hyaluronic acid in an attempt to alleviate symptoms. An unrelated screening colonoscopy was performed soon after, revealing a submucosal rectal lesion. Flexible sigmoidoscopy and endoscopic rectal ultrasound with FNA were scheduled for patient for further evaluation. An unknown foreign material was noted under microscopy and, upon attaining additional history, the gastroenterologist uncovered the patient's recent injections of dextranomer/hyaluronic acid.

CONCLUSION

Dextranomer/hyaluronic acid for the treatment of fecal incontinence has become more common in recent years. Though the imaging and histologic appearance of this gel-like material is seen in other areas of medicine, equivalent descriptions are limited in the anorectal region. To curb misdiagnoses and prevent unnecessary interventions, it is important to expound on the endoscopic, imaging, and histopathologic features of this tissue-bulking agent in the setting of fecal incontinence and to encourage communication, proper documentation, and easy accessibility to patient health information by all medical staff.

Vesicoureteral reflux and the extracellular matrix connection

Primary vesicoureteral reflux (VUR) is a common pediatric condition due to a developmental defect in the ureterovesical junction. The prevalence of VUR among individuals with connective tissue disorders, as well as the importance of the ureter and bladder wall musculature for the anti-reflux mechanism, suggest that defects in the extracellular matrix (ECM) within the ureterovesical junction may result in VUR. This review will discuss the function of the smooth muscle and its supporting ECM microenvironment with respect to VUR, and explore the association of VUR with mutations in ECM-related genes.

[Secondary megaureter: A rare complication of Deflux® endoscopic management of vesicoureteral reflux in children]

Endoscopic management is the gold standard for symptomatic low-grade vesicoureteral reflux (VUR) in children. Deflux^® (hyaluronic acid/dextranomer) injection is highly effective and has very few complications. We report on two cases of secondary megaureter after Deflux^® injections. In the first case, a boy presented with Grade 4 VUR. He received a bilateral Deflux^® injection with a total of three syringes. The postoperative ultrasound was normal. However, a check-up ultrasound 3 years later showed a significant ureteropyelocalyceal dilatation, with stasis and decreased renal function on scintigraphy, the reason why antireflux surgery (Cohen procedure) was performed. In the second case, a girl diagnosed with bilateral VUR at birth received bilateral injections with one syringe on each side at the age of 12 months. One month later, the ultrasound showed a dilation of the distal ureters (diameter of the right ureter, up to 10mm; left ureter, up to 6.7mm). The child underwent surgery 8 months later (Cohen procedure) because of iterative pyelonephritis and persistent ureter dilatation. Only one previous case has been described in the literature. In our experience, this complication has occurred only twice in 452 injections (4‰). In conclusion, endoscopic treatment with hyaluronic acid/dextranomer injection is a minimally invasive procedure that improves the situation in cases of VUR. It has few complications. Other than failure, there is a low risk of secondary expansion requiring, in our opinion, ultrasound verification over the long term.

Endoscopic treatment of vesicoureteral reflux: current practice and the need for multifactorial assessment

Vesicoureteral reflux (VUR) affects around 1% of all children. It carries an increased risk of febrile urinary-tract infections (UTIs) and is associated with impaired renal function. Antibiotic prophylaxis is an established approach to managing the condition, but it does not protect against UTI and encourages bacterial resistance. Ureteral re-implantation (open surgery) is a relatively traumatic procedure typically requiring hospitalization, and there is a risk of significant post-treatment complications. Endoscopic treatment with NASHA/Dx gel (Deflux®) is minimally invasive, well tolerated and provides cure rates approaching those of open surgery: 80-90% in several studies. It has also been shown to be effective in a variety of 'complicated' cases. Thus, endoscopic treatment is generally preferable to open surgery and long-term antibiotic prophylaxis. Non-treatment of VUR is being discussed as an alternative option, although this mainly appears suitable for children with low-grade reflux and normal kidneys. A new approach to managing VUR may be considered, with treatment decisions based not only on the grade of reflux but also on factors such as age, sex, renal scarring and bladder dysfunction. Open surgery would be reserved only for use in the 10-15% of children not responding to endoscopic treatment and those with severe ureteral anomalies.

Cystoscopic injections of dextranomer hyaluronic acid into proximal urethra for urethral incompetence: efficacy and adverse outcomes

OBJECTIVES

To determine whether dextranomer/hyaluronic acid would be more efficacious or would produce fewer complications when using the material in a standard proximal-urethra cystoscopically-directed injection technique. Injectable periurethral bulking agents are an alternative to stress incontinence surgery. Dextranomer, a highly hydrophilic dextran polymer, solubilized in a base of nonanimal stabilized hyaluronic acid, has been approved as an injectable agent for the treatment of childhood vesicoureteric reflux (Deflux, Q-Med AB, Uppsala, Sweden), and in Europe for women with stress urinary incontinence (SUI) (Zuidex, Q-Med AB, Uppsala, Sweden). A previous multicenter trial demonstrated nonequivalence compared with bovine glutaraldehyde cross-linked collagen with a high complication rate. We sought to determine whether the failure of the treatment lay in the material itself or the use of a blind, midurethral injection technique.

METHODS

A retrospective case series of 56 patients undergoing cystoscopically guided bladder neck injections of dextranomer/hyaluronic acid with follow-up in 42, included 35 women with intrinsic sphincter deficiency (ISD), 4 men with postprostatectomy incontinence, 2 men with sphincteric denervation secondary to spinal cord injury, and 1 woman with sphincteric failure after a neobladder. Outcome assessment used gender-appropriate International Consultation on Incontinence Questionnaire, clinical records, and/or urodynamic assessment.

RESULTS

Of 35 women with ISD, 4 developed pseudoabscess formation with outlet obstruction requiring multiple operative interventions. Patient-defined treatment failure occurred in all 4 carefully selected postprostatectomy incontinent men, and in 23 of 35 females with ISD.

CONCLUSIONS

Complications with cystoscopically injected dextranomer hyaluronic acid at the bladder neck occurred at a high rate, and using a validated questionnaire, the efficacy of dextranomer hyaluronic acid applied in this manner for ISD was poor.