Efficacy and safety of botulinum toxin a injection into urethral sphincter for underactive bladder.

BACKGROUND

The aim of this retrospective study was to evaluate the clinical efficacy and safety of botulinum toxin type A (BTX-A) injection into the urethral sphincter to treat patients with underactive bladder (UAB).

METHODS

From September 2012 to December 2018, 35 patients with UAB who presented with dysuria were treated with BTX-A (Prosigne®, Lanzhou Biological Products, Lanzhou, China). All patients were evaluated using the International Continence Society standard for video-urodynamic examination before and 1 month after treatment. The index includes maximum urinary flow rate, detrusor leak point pressure, and maximum urethral pressure. Post-voiding residual urine volume was measured using ultrasound before, one and 3 months post injection.

RESULTS

After 1 month of treatment, the maximum flow rate increased from 2.5 ± 1.1 ml/s to 6.6 ± 1.7 ml/s (P < 0. 05). The maximum urethral pressure decreased from 73.5 ± 5.8 cmH2o to 45.6 ± 4.3cmH2O (P < 0. 05). The detrusor leak point pressure decreased from 69.9 ± 20.7cmH2O to 26.3 ± 7.4cmH2O (P < 0. 01). Post-voiding residual urine decreased from 282.8 ± 134.2 ml to 125.0 ± 92.1 ml (P < 0. 01) but increased to 270.1 ± 129.0 ml 3 months post injection. Of the 35 patients, 57.1% (20/35) relied on clean intermittent catheterization (CIC) before injection, but 75.0% (15/20) of them could partly void 1 month after injection, and 25%(5/20) could void without CIC. Eight patients showed hydronephrosis before treatment; in three of them, hydronephrosis decreased slightly, while it resolved in two. All patients were followed for three to 6 months, and the effect lasted for about two to 3 months. No serious adverse events occurred in any patient.

CONCLUSIONS

The results suggest that Prosigne® injection into the urethral sphincter is an effective, safe, and inexpensive way to treat UAB.