In a pilot study, Groen and colleagues (2005) evaluated the results of chronic pudendal nerve neuromodulation (CPNN) on women with idiopathic refractory detrusor over-activity incontinence. A percutaneous screening test (PST) was performed in patients with urodynamically demonstrated detrusor over-activity incontinence. Such a test includes the performance of a cystometrogram without and with percutaneous pudendal nerve stimulation and is considered positive if stimulation results in a more than 50 % increase in the bladder volume at the first involuntary detrusor contraction or the maximum cystometric capacity. Patients with a positive PST qualified for the implantation of a mini-neurostimulator with an integrated electrode, a so-called Bion(R), adjacent to the pudendal nerve at Alcock's Canal. Five-day voiding-incontinence diaries were the main tool for the evaluation of therapy. A PST was performed in 14 women; 6 patients responded positively and received a Bion(R). The degree of incontinence decreased significantly in this group, which also included patients in whom sacral neuromodulation had failed. There were no severe adverse events. The authors concluded that CPNN may reduce the degree of detrusor over-activity incontinence, even in patients in whom sacral neuromodulation fails.