Durability, safety and efficacy of polyacrylamide hydrogel (Bulkamid(®)) in the management of stress and mixed urinary incontinence: three year follow up outcomes

Urethral Bulking

OBJECTIVE

This Clinical Practice Statement aims to provide clinicians with evidence-based guidance for the use of urethral bulking agents (UBAs) in the treatment of stress urinary incontinence (SUI).

METHODS

We conducted a structured search of the English literature published from January 1960 to November 2022. Search terms identified studies of both current and historic UBAs. Data extracted at the time of full-text review included type of study, research setting, number of participants, age group, bulking agent, primary outcome, secondary outcome, efficacy, and complications.

RESULTS

One thousand five hundred ninety-four nonduplicate articles were identified using the search criteria. After limiting the article types to randomized control led trials, prospective studies, guideline documents, reviews, meta-analyses, and case reports of complications, 395 studies were screened.

CONCLUSIONS

Based on our findings, we propose the following recommendations for clinicians when considering UBA: First, UBA is indicated in cases of demonstrable SUI. Intrinsic sphincter deficiency is not predictive of patient outcomes. Second, patients should be counseled on the risks, lack of long-term efficacy data, potential need for repeat injections, possible need for surgery for recurrent SUI, implications for future procedures, and pelvic imaging findings that may be observed after UBA. Third, UBA may be considered for initial management of SUI. Fourth, UBA is an option for patients with persistent or recurrent SUI after a sling procedure. Fifth, clinicians may prioritize UBA over surgery in specific patient populations. Sixth, polyacrylamide hydrogel demonstrates marginally improved safety and durability data over other available agents.

Reconstruction of Urethral Sphincter With Polyacrylamide Hydrogel

IMPORTANCE

Urethral bulking is an alternative to synthetic midurethral sling for the treatment of stress urinary incontinence (SUI) in women. Urethral bulking agents, which are injected in the submucosal tissues of the proximal urethra/bladder neck, have demonstrated less adverse effects with similar satisfaction rates but lower subjective and objective cure rates when compared with midurethral sling. Cystoscopic Reconstruction of External Sphincter Technique (CREST) is a novel technique, which reinforces the natural closure mechanism of the external urinary sphincter (EUS).

OBJECTIVE

The aim of the study was to provide safety and efficacy data for injecting polyacrylamide hydrogel (PAHG) in the components of the female EUS.

STUDY DESIGN

This was a retrospective chart review of patients using CREST with PAHG as initial treatment for SUI by a single surgeon from January 2022 to October 2022. Exclusion criteria are as follows: younger than 18 years, prior SUI surgery, concomitant pelvic organ prolapse or reconstructive procedure, neurological conditions, or history of radiation. Subjective and objective cure rates were measured by patient-reported symptoms and cough stress test. Urinary retention, postoperative urinary infection, and de novo urinary urgency were assessed.

RESULTS

One hundred and thirteen consecutive patients met inclusion criteria with median follow-up of 3 months. Eighty-five percent of participants reported subjective improvement, 69% reported subjective cure, and 69% demonstrated objective cure. Nine patients reported transient postoperative retention, 8 reported postoperative urinary tract infections, and 5 reported de novo urgency. There were no serious adverse events.

CONCLUSIONS

CREST is a novel technique for injection of PAHG, into the EUS to treat SUI. Our data suggest that this technique could improve urethral injection outcomes with minimal complications.

Could infiltration anesthesia decrease anchor-fixation quality of midurethral slings in the obturator complex?

INTRODUCTION

Single-incision miduretral slings (SIMS) were withdrawn from the market in many countries due to lower efficacy. In some countries they are still in use, preferred primarily because it is possible to perform the procedure under local anesthesia. Based on our previous clinical experience we postulated that local anesthesia decreased primary anchor fixation in the obturator complex. The aim of the study is to assess how local infiltration anesthesia influences anchor fixation of the tape in porcine obturator complex.

METHODS

The experiment was designed to determine the maximum force necessary to extract an implant anchor from a porcine obturator complex. The implant was extracted at a constant speed and data sampling frequency, and the data on displacement of the testing system, achieved force and time were recorded. The implant arms were divided into groups on the right and left sides. In the first group, the anchored arms were used for two implantations - primary and secondary without infiltration anesthesia - and in the second group they were used in the same way, using infiltration anesthesia.

RESULTS

A total of 40 implanted anchors were tested in the experiment, totaling ten single-incision slings (each anchor was implanted twice). An average of 8.28 N (Newton) (SD 6.73, min. 2.11, max. 30.34 N) is required to remove the implant anchor from the obturator complex without infiltration by local anesthesia. An average force of 4.40 N (SD 2.99 min. 1.2, max. 9.48) is required to remove the anchor from the obturator complex after infiltration. Local anesthesia reduces anchor fixation in the obturator complex by 47%.

CONCLUSIONS

The local infiltrative anesthesia decreases anchor fixation in the porcine obturator complex.

Hydrogels for Tissue Engineering: Addressing Key Design Needs Toward Clinical Translation

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Urethral bulking agents: a retrospective review of primary versus salvage procedure outcomes

PURPOSE

Urethral bulking agents (UBA) have traditionally been offered as salvage procedures for recurrent stress urinary incontinence (SUI). We compare the success of UBA in patients that had undergone a previous procedure for SUI (Salvage-UBA) to the SUI surgery naïve (Primary-UBA). We hypothesised a positive effect in both Primary and Salvage-UBA with potentially poorer rates of response in the salvage group.

METHODS

Retrospective case series of patients having their first UBA (2010-2018). Primary outcome was to assess any difference in patient reported success between groups. Patient-reported improvement was assessed on a 4-point scale: 'cured, improved, no change, worse' and treatment 'success' defined as 'cured' or 'improved'. A multivariate analysis, adjusting for plausible differences between groups, was undertaken in IBM SPSS Statistics (2016).

RESULTS

135 Primary-UBA and 38 Salvage-UBA were performed. Complete follow-up was obtained for 114 patients (66%): 86 Primary and 28 Salvage. Median follow-up time: 33 months. In 2012, 47% (8/17) of all UBA were Salvage-UBA, whilst in 2018, the majority were Primary-UBA (92%, 46/50). Success was not significantly different between Salvage-UBA 75% (21/28) versus Primary-UBA 67% (58/86) (Wald χ² = 0.687, df = 1, p = 0.407). Top-up rates were similar: 14% (n = 4/28, Salvage-UBA) versus 15% (n = 13/86, Primary-UBA) (χ² = 0.011, df = 1, p = 0.914).

CONCLUSION

The number of women opting for UBA has increased substantially. No significant differences were noted for success with Salvage-UBA compared to Primary-UBA.

Particulate Versus Non-Particulate Bulking Agents In The Treatment Of Stress Urinary Incontinence

Stress urinary incontinence (SUI) has been treated surgically with the midurethral sling but in recent years, this option has come under scrutiny and the risk-benefit balance continues to be reviewed. The low-risk alternative for women with uncomplicated SUI is the bulking agent, which aims to achieve continence through coaptation of the urethra. Two classes of bulking agents can be identified: those made from solid microparticles in an absorbable liquid or gel carrier (particulate agents) and those comprising a homogenous gel (non-particulates) that resists absorption. Polydimethylsiloxane®, carbon-coated zirconium oxide®, calcium hydroxyapatite® and polyacrylate polyalcohol copolymer® are currently marketed particulate agents. With the exception of calcium hydroxyapatite, the particles are non-degradable. Each agent achieves its long-term bulking effect through reactive changes around the persisting particles while the carrier volume is lost. Bulkamid® is a non-particulate agent with the bulking effect resulting from the volume of gel injected. The lasting network of fine fibers formed by the host tissue anchors the gel in situ. Foreign-body granulomas, erosion and migration/material extrusion and loss of bulk have been observed in connection with the particle-based products. Bulkamid may be mechanistically less liable to these events; however, there are minimal data directly comparing the two types of bulking agent. The question of durability is inevitable based on their differing modes of action.

Adverse Events Associated with Nonsurgical Treatments for Urinary Incontinence in Women: a Systematic Review

BACKGROUND

Urinary incontinence (UI) is a common malady in women. Numerous nonsurgical treatments are available, each associated with risk of adverse events (AEs).

METHODS

We systematically reviewed nonsurgical interventions for urgency, stress, or mixed UI in women, focusing on AEs. We searched MEDLINE®, Cochrane Central Trials Registry, Cochrane Database of Systematic Reviews, and Embase® through December 4, 2017. We included comparative studies and single-group studies with at least 50 women. Abstracts were screened independently in duplicate. One researcher extracted study characteristics and results with verification by another independent researcher. When at least four studies of a given intervention reported the same AE, we conducted random effects model meta-analyses of proportions. We also assessed the strength of evidence.

RESULTS

There is low strength of evidence that AEs are rare with behavioral therapies and neuromodulation, and that periurethral bulking agents may result in erosion and increase the risk of voiding dysfunction. High strength of evidence finds that anticholinergics and alpha agonists are associated with high rates of dry mouth and constitutional effects such as fatigue and gastrointestinal complaints. Onabotulinum toxin A (BTX) is also associated with increased risk of urinary tract infections (UTIs) and voiding dysfunction (moderate strength of evidence).

DISCUSSION

Behavioral therapies and neuromodulation have low risk of AEs. Anticholinergics and alpha agonists have high rates of dry mouth and constitutional effects. BTX is associated with UTIs and voiding dysfunction. Periurethral bulking agents are associated with erosion and voiding dysfunction. These AEs should be considered when selecting appropriate UI treatment options. AE reporting is inconsistent and AE rates across studies tended to vary widely. Trials should report AEs more consistently.

Functional Outcome of Human Adipose Stem Cell Injections in Rat Anal Sphincter Acute Injury Model

Anal incontinence is a devastating condition that significantly reduces the quality of life. Our aim was to evaluate the effect of human adipose stem cell (hASC) injections in a rat model for anal sphincter injury, which is the main cause of anal incontinence in humans. Furthermore, we tested if the efficacy of hASCs could be improved by combining them with polyacrylamide hydrogel carrier, Bulkamid. Human ASCs derived from a female donor were culture expanded in DMEM/F12 supplemented with human platelet lysate. Female virgin Sprague‐Dawley rats were randomized into four groups (n = 14–15/group): hASCs in saline or Bulkamid (3 × 10⁵/60 μl) and saline or Bulkamid without cells. Anorectal manometry (ARM) was performed before anal sphincter injury, at two (n = 58) and at four weeks after (n = 33). Additionally, the anal sphincter tissue was examined by micro‐computed tomography (μCT) and the histological parameters were compared between the groups. The median resting and peak pressure during spontaneous contraction measured by ARM were significantly higher in hASC treatment groups compared with the control groups without hASCs. There was no statistical difference in functional results between the hASC‐carrier groups (saline vs. Bulkamid). No difference was detected in the sphincter muscle continuation between the groups in the histology and μCT analysis. More inflammation was discovered in the group receiving saline with hASC. The hASC injection therapy with both saline and Bulkamid is a promising nonsurgical treatment for acute anal sphincter injury. Traditional histology combined with the 3D μCT image data lends greater confidence in assessing muscle healing and continuity. Stem Cells Translational Medicine2018;7:295–304