Botulinum toxin A injection to the bladder neck and urethra for medically refractory lower urinary tract symptoms in men without prostatic obstruction.

BACKGROUND/PURPOSE: Lower urinary tract symptoms (LUTS) in men with small benign prostatic hyperplasia (BPH) might not result from prostatic compression. Instead, bladder neck and urethral dysfunction could play an important role. We investigated the effect of botulinum toxin A (BoNT-A) injection to the bladder neck and urethra of men with small BPH and LUTS that were refractory to medical treatment.

METHODS

We enrolled 30 men with a total prostate volume (TPV) of < 40 mL, International Prostate Symptom Score (IPSS) > 12, and maximum urinary flow rate (Qmax) < 15 mL/second, who were refractory to medical treatment. None had bladder outlet obstruction upon videourodynamic study. One hundred units of BoNT-A dissolved in 10 mL normal saline was injected at 10 sites at the trigone, bladder neck, proximal urethra, distal urethra and external sphincter. The values for IPSS, quality of life (QoL) index, Qmax, bladder capacity, post-void residual (PVR), TPV and global satisfaction at 1, 3 and 6 months after injection were compared with baseline.

RESULTS

Significant improvements in empty and total IPSS were found at 1 and 3 months but not 6 months after treatment. Qmax significantly increased at 1 month and was still improved at 6 months. Bladder capacity increased and PVR decreased at 1 and 3 months but not at 6 months after treatment. QoL index and global satisfaction were improved significantly at all time points after treatment.

CONCLUSION

Bladder neck and urethral BoNT-A injections improved LUTS and increased Qmax in men with a small prostate. Our findings suggest that bladder neck and urethral dysfunction may play a role in LUTS in men without BPH.