Stimulation of the pudendal afferent dorsal genital nerve (DGN) nerve has been used in experimental settings for more than three decades, and this stimulation method has shown promising results for treating overactive bladder syndrome (OAB). The stimulation can be continuous, intermittent, and on-demand. A previous urodynamic study has shown that detrusor overactivity can be inhibited by on-demand DGN stimulation (1). DGN stimulation has some potential advantages compared to Sacral Nervemodulation or percutaneous tibial nerve stimulation, as the DGN only contains afferent sensory fibers, the nerve can be stimulated by a surface electrode and potentially be used on-demand as DGN has a reflex for inhibition of the detrusor. 
The UCon neurostimulator is a new electrical device with a Control Unit, which provides electrical stimulation, a silicone-electrode for clitoral/dorsal penile nerve stimulation, and a reference electrode (figure 1). The stimulator has two operation modes: 1) Time-limited stimulation, and 2) On-demand stimulation. On-demand stimulation can be activated by pressing the urge button on either the Control Unit or the Remote Control.  
The aim of the study was to test this new Ucon Neurostimulator on women and men with OAB in a home setting. The hypothesis was that the neurostimulation was safe without serious adverse events and that the two operation modes would decrease the number of urgency urinary incontinence (UUI) episodes and urinary frequency in patients with OAB.

The study was a prospective, multicenter, open label feasibility-study. Inclusion criteria were patients ≥18 years with OAB. Exclusion criteria were intravesical Onabotulinum toxin A treatment within three months and administration of antimuscarinics or Beta-3 Agonists within two weeks. As baseline measure the patients filled in a 7-day diary including UUI episodes, number of voids, and fluid intake. After the baseline measure, the patients were allocated to one of the two treatment protocols based on the patients’ preference. First protocol included a time-limited stimulation, where the patient stimulates the DGN 30 minutes on clitoris/dorsal penis each day. Second protocol included an on-demand stimulation, where the patient wears the equipment during the daytime and can manually activate the DGN stimulation during urgency episodes. The treatment periods were 4 weeks in both protocols.

Seventeen patients (4 male and 13 female patients) were included in total. Six patients (5 female patients) were included in the time-limited stimulation, eight (6 female patients) in the on-demand stimulation, and four patients (3 female patients) signed informed consent but were excluded as they discontinued the study (n=3) or were screenings failure (n=1). One female patient completed the on-demand stimulation and was after a non-stimulation period of three weeks included in the time-limited stimulation where she completed a new baseline diary. She had positive effect of both regimes. 
No serious adverse events were experienced during the study period. Three patients (2 female patients) discontinued the study after 3, 9 and 9 days with stimulation due to technical issues with the equipment, pain during stimulation and lack of effect.  
All six patients in the time-limited stimulation had fewer UUI episodes during the stimulation compared to the baseline measurements (Baseline: mean 2.2 UUI episodes/day, intervention: 0.6 UUI episodes/day, p<0.05). One man became continent during the stimulation period (figure 2). The mean number of voids per day decreased insignificantly from 11.4 to 10.0 (5 experienced fewer and 1 experienced more voids per day) 
During the on-demand stimulation five female patients had fewer UUI episodes, one man had the same number of UUI episodes, and two patients had more UUI episodes (one of the patients did not have UUI on the baseline diary but 0.6 UUI episodes/day during intervention) (Baseline: mean 2.4 UUI episodes/day, intervention: 1.9 UUI episodes/day, NS) (figure 2). None became continent. Seven subjects experienced fewer voids per day during the treatment while one had more voids (12.0 to 10.6 voids/day, NS).

These first clinical data with UCon neurostimulator are very promising. The treatment is non-invasive and seems to be well tolerated. Ten out of 13 patients had fewer UUI episodes during the two treatment protocols, while 11 out of 13 patients had fewer voids (one female patient was included in both protocols and had fewer UUI and voids during both stimulations). One patient in each protocol had more voids during the intervention and two patients had more UUI episodes during the on-demand stimulation treatment.

These first clinical results of the UCon neurostimulator are promising for treatment of patients with OAB. 
Larger studies with longer treatments periods including randomized placebo-controlled trials are needed to establish the benefit of the UCon neurostimulator.

Dorsal Genital Nerve Stimulation in Patients with Detrusor Overactivity: A Systematic Review. Curr Urol Rep (2012) 13:385–388

Continence 7S1 (2023) 100744
DOI: 10.1016/j.cont.2023.100744