<p>Particulate Versus Non-Particulate Bulking Agents In The Treatment Of Stress Urinary Incontinence</p>

Abstract

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.

Seven‐year efficacy and safety outcomes of Bulkamid for the treatment of stress urinary incontinence

“…Currently, two different types of bulking agents are used. The first type contains particles that cause inflammation, and this reaction gives support around the urethra 5 . The second type of bulking agent is a homogenous gel without particles.…”

Urethral bulking agents for SUI: Rethinking their indications

“…The aqueous gel carrier dissipates over months, resulting in tissue growth; thereafter, the particulate beads slowly degrade. 12 Macroplastique, a polydimethylsiloxane compound, was approved by the FDA in 2006. It has a long history of use primarily in Europe where it has been used since 1991.…”

“…Reported adverse effects associated with urethral bulking include mild pain, transient urinary retention (typically resolving within 1-2 days after injection), dysuria, hematuria, and urinary tract infection (UTI). 4,12 In a 12-month RCT involving 355 women treated with Durasphere or bovine collagen, adverse events were reported in 178 Durasphere-treated women; dysuria (24.7%) and temporary urinary retention (16.9%) were the most commonly reported adverse events. 20 An RCT of Coaptite injection (n = 296) found that temporary urinary retention (41%) was the most common adverse event.…”

“…18 It appears that transient dysuria, urgency, and urinary retention occur more frequently after urethral bulking with particulate agents. 12 Complications. Few delayed but serious complications after urethral bulking have been reported, including suburethral abscess, urethral prolapse, and particle migration.…”

“…21,22 Cases also have been reported of Durasphere carbon bead particles migrating to regional and distant lymph nodes, and pseudoabscess also has been reported. 12,23 A single case of periurethral abscess was reported after Bulkamid injection in a patient who had prior vaginal hysterectomy and a transobturator tape procedure after a total vaginal mesh repair. 24 Bulking agent use: Time to go mainstream?…”