To determine
1. If SBD of the trigone results in improvement of OAB symptoms 
2. Durability and safety profile of SBD treatment

Women with OAB who had failed medical therapy were recruited for this multicenter multinational study using a novel treatment with RF energy to selectively ablate the nerve rich layers of the deep detrusor and adventitial space below the trigone while sparing the bladder mucosa and surrounding pelvic viscera. Patients with ≥3 urgency urinary incontinence (UUI) episodes in 3 days and ≥8 voluntary voids per 24h were eligible.  Normal lower urinary tract anatomy was confirmed based on history, physical examination, renal and bladder ultrasound and pre-procedure cystoscopy. After washout of oral OAB medications, OAB diagnosis was confirmed by history and 3-day voiding diary which included the patient perception of intensity of urgency scale (PPIUS) for each void. All patients had prophylactic antibiotics and either a general anesthetic or conscious sedation. SBD treatment consisted of cystoscopically guided 60 sec ablations repeated to cover the span of the trigone (average of 4 ablations per patient). The optimal technique and ablation parameters for SBD were developed in a series of ovine ex-vivo and in-vivo experiments which have been previously reported (in press). A visual analogue scale was used to assess post procedure pain at 4h prior to discharge on the same day. Pre- and post-procedure assessment at 4, 12, 26 and 52 weeks consisted of 3-day diaries, OABq SF and Kings Health Questionnaire (KHQ) and follow up capture of treatment benefit scale (TBS) and adverse events (AE) adjudicated by an independent committee. Total Urgency and Frequency Score (TUFS) per 24h was computed by summing the urgency score of every void and dividing by the number of days of diary capture (1).

Of the 35 patients enrolled, 18 have completed 12-month follow up to date. Efficacy data is presented only on those patients who remained in the study, and had diary data available and who had not had additional therapy (see Table). The average age and duration of OAB was 66.1±8.7 and 9.8±7.7 years respectively. Some patients (n=8) had previously failed other 3rd line therapies (Botox: 4, SNM 2, PTNS 2). Procedure related adjudicated AEs were all noted within 4 weeks of treatment and the most common was UTI that occurred in 4 patients (11%), all other AEs were single occurrences (<3%). Of note, the treatment did not result in urinary retention requiring catheterization. One device and procedure related SAE occurred in a patient with an undiagnosed ureterocele which after the procedure resulted in transient ureteric obstruction, hydronephrosis, and pyelonephritis that was treated with antibiotics and a double J stent for 10 weeks. Upon removal of the stent, the obstruction was resolved and the patient continues to have improvement of her OAB symptoms.

These data suggest that SBD is well tolerated and results in durable improvement in OAB symptoms without interfering with normal bladder function. The effect of the procedure appears to last for at least 12 months, and possibly longer. 

In this uncontrolled study, a reduction in TUFS measure mitigates against the possibility of defensive voiding resulting in a reduction of urgency and UUI episodes.

The results support the neurogenic hypothesis for the etiology of OAB and suggest that the trigone is an appropriate area of focus for OAB treatments.

1. SBD appears to be effective in reducing the cardinal symptoms of OAB: urgency and urgency incontinence.
2. The procedure was well tolerated and appears to be safe in the absence of lower urinary tract abnormalities.
3. A single treatment appears to have durable efficacy without long term side effects.
4. A larger sham controlled study is needed to confirm these results.
5. The results support a neurogenic etiology of OAB.

Chapple et al. Total urgency and frequency score as a measure of urgency and frequency in overactive bladder and storage lower urinary tract symptoms. BJU Int. 2014; 113: 696–703