Botulinum Toxin Urethral Sphincter Injection for Dysfunctional Voiding - A Multicenter Study, Randomized, Double-Blind, Placebo Control

This study is designed in a randomized, double-blind, placebo controlled, multicentric trial. A total of 60 patients will be enrolled. All patients have suffered from dysfunctional voiding that is refractory to conventional treatment. The enrolled patients should have severe dysuria or urinary retention, large residual urine and have been treated with medication or other therapeutic modality for over 3 months. The patients will be randomly assigned to allocate in the treatment and control groups in a 2:1 ratio. About 40 and 20 patients will be enrolled in the treatment and control group, respectively.

This study should be approved by the Institutional Review Board (IRB) and ethical committee of the hospital. Every patient should be thoroughly informed and written informed consent should be obtained before treatment.

Patients will receive a complete urological work-up before treatment, including urinalysis, urine culture, cystoscopy to prove no anatomical stricture or lower urinary tract pathology, and videourodynamic study. All medication that may affect the lower urinary tract function will be stopped at least 1 week before Botulinum Toxin A (BoNT-A) injection.

Videourodynamic study will be performed with the patient in supine position if patients cannot stand up or sit on the commode. A 6 Fr dual channel urethral pressure profiles (UPP) urethral catheter will be inserted to the urinary bladder. After evacuation of the residual urine, urethral pressure profilometry will be performed first. Then the bladder will be filled with normal saline containing 20% urografin at the filling rate of 30 ml/min. The filling and voiding cystourethrography will be investigated by a C-arm positioned below the patient. Uroflowmetry is recorded by a weighed transducer placed below the examination table. After the bladder is filled to the capacity, the patients are asked to urinate per urethrae. If patient cannot urinate per urethrae with the urethral catheter in situ, suprapubic puncture with a 18 Gauge needle and a 3-Fr epidural catheter will be undertaken and patients will urinate without the catheter in the urethra. The patients are requested to stand up and urinate into the commode. Pressure flow study and concomitant voiding cystourethrography are performed.

The urodynamic parameters include maximal urethral closure pressure (MUCP), functional profile length (FPL), cystometric bladder capacity (CBC), bladder compliance, voiding detrusor pressure (Pdet), maximal flow rate (Qmax), voided volume, and postvoid residual urine volume (PVR). In the patients who have detrusor underactivity, the abdominal pressure to urinate and the detrusor leak point pressure will be measured. Images of voiding cystourethrography will be emphasized on the bladder neck opening, urethral sphincter relaxation, and dilatation of posterior urethra during voiding.