Urethra bulking is a well-established endoscopic intervention for female stress incontinence. Current bulking agents include Bulkamid® and Macroplastiue®. Deflux® is a Non-Animal Stabilised Hyaluronic Acid (NASHA) and Dextranomer (Dx) agent used commonly in paediatric vesicoureteral reflux, with proven good safety profile and clinical effectiveness. However, though licenced in the UK, clinical data on its role in adult urethral bulking is lacking. In this study, we investigated the efficacy and safety of Deflux as urethral bulking agent in treatment of adult female stress incontinence.

51 female patients, with urodynamics proven stress incontinence received urethral bulking with Deflux from 2021 to 2023, with follow up planned for 12 months. In lithotomy position under general anaesthetic, with intravenous Gentamicin prophylaxis, 2 millilitres of Deflux was injected endoscopically at the bladder neck, using a 22-gauge flexible needle via a rigid cystoscope. Treatment success (dry) was defined as using 1 or fewer pad for reassurance only per day. Clinical effectiveness was determined by comparing pre- and post-procedure ICIQ-UI (Short form) scores, number of pads used in 24 hours, and weight of leaked urine, by measuring the sum of pad weight within 24 hours.

Statistical analyses were performed with R (version 4.3.0). Paired t-test was used to compare the outcome variables pre-procedure and at follow-up. Logistics regression was performed to delineate relationship between baseline characteristics and outcome variables.

At 3 months, 28 in 51 (55%) of patients were dry. Mean number of pads used reduced by 57%, from 3.2 to 1.4 (p≤0.001). Average weight of 24-hour leaked urine was reduced by 76%, from 225g to 54g (p=0.05). Mean ICIQ also decreased from 15.7 to 7.8 3-month after the injection (p≤0.001, Figure #1).

Logistic regression of baseline characteristics shows the number of pads pre-procedure and baseline ICIQ are both statistically significant predictors of treatment success (p≤0.01 and p=0.04, Figure #2).

A complication rate of 6% was observed, namely urinary tract infections (n=2, treated with antibiotics) and urinary retention (n=1, treated by temporary catheter). These are minor complications which affected only a small group of patients in our study.

A significant proportion of patients remain dry after 3 months of Deflux injection, showing its short-term clinical efficiency. This treatment success is further proven by the statistically significant improvement of weight of urine leakage and mean ICIQ at follow-up. 

Patients with lower number of pads and ICIQ at baseline have less bothersome stress urinary incontinence, and thus a better treatment response is expected from such group of patient.

Deflux is a clinically effective and safe bulking agent in female stress incontinence treatment. By utilising a flexible needle with rigid cystoscopy which is already readily available in most Urology departments, Deflux is thus a cost-effective choice of bulking agent. Longer term follow up for 12 months is ongoing to confirm longevity of efficacy as well as safety profile.