Stress urinary incontinence is a common problem which can have devastating effects on patient’s quality of life. When conservative treatment measures have proved ineffective, surgical modalities are sought with a number of available options. Given the current controversies surrounding synthetic tapes, there has been an increased emphasis on alternative techniques such as urethral bulking agents. Despite being minimally invasive, these agents have the potential to cause significant complications requiring salvage procedures. Several agents currently exist with most demonstrating promising short term results however long term data is limited. Macroplastique® (polydimethylsiloxane injection, MPQ) is a minimally invasive urethral bulking agent with global clinical literature describing its use over 20 years and was deemed to be ‘effective, durable, and a safe treatment option’ (1) in a recent meta-analysis. Reports of complications from MPQ use are uncommon, however, in recent years we have encountered a number of erosions associated with its use and have collated these in our dual centred case series.

Patients were identified via a review of prospectively maintained databases from two different high volume tertiary referral centers. The data from one center covered a 6 year period ranging from January 2012 – March 2019, while the data from another center covered a 2 year period from 2016 to 2018.

A total of 9 patients were identified at tertiary referral center. Dates of original insertion ranged between 2002 – 2005. All patients were referred due to complaints of recurrent urinary tract infections (UTI). They all underwent a cystoscopy which confirmed erosion of the MPQ + / - calcification with 2 cases involving the bladder. All patients underwent transurethral resection of the implant with 2 patients requiring a re-resection. 6 patient had recurrence of SUI with 2 requiring an autologous sling. 7 patients had complete resolution of the their recurrent UTI’s.

A total of 5 patients were identified at a second tertiary referral center. Dates of original insertion ranged between 2011 – 2016.  All patients had undergone MPQ injection for stress urinary incontinence secondary to intrinsic sphincter deficiency and had developed subsequent recurrent urinary tract infections (UTI). They all underwent a cystoscopy which confirmed erosion of the MPQ + / - calcification with one case involving the bladder neck. Three patients underwent transurethral resection of the implant with 1 patient requiring a re-resection for residual implant. Two patients are being managed conservatively and are stable under observation, occasionally requiring antibiotics for UTIs flare-ups. Of the 3 patients that underwent implant resection, all had recurrence of SUI with 2 requiring a subsequent autologous fascial sling with resolution of their incontinence. All 3 patients who underwent MPQ resection had complete resolution of their recurrent UTI’s.

In general terms, MPQ erosion commonly results in recurrent UTIs. There can be a significant delay between the implant injection and the occurrence of UTIs. Occasionally, the patient may have forgotten about the MPQ injection since it is a minimally invasive procedure. Following excision of MPQ, the patients are highly likely to have recurrence of their SUI and need to be appropriately counselled. By in large recurrent UTIs are successfully treated with excision of the eroded implant.

Despite large scale reviews highlighting the safety of MPQ use, complications are encountered. One should be highly vigilant of the possibility of erosion in patients who present with recurrent urinary tract infection, voiding dysfunction or pain after MPQ injection. A thorough assessment is requiring including cystoscopy with or without a pelvic MRI. They appear as yellow, spongiform protrusion and can be difficult to identify on cystoscopy. Monopolar resection is challenging due to the insulating property of its silicone chemical make-up, bipolar resection may therefore be preferred.

Ghoniem GM, Miller CJ. A systematic review and meta-analysis of Macroplastique for treating female stress urinary incontinence. International Urogynaecology Journal. 2013;24(1):27-36