Sacral neuromodulation for urinary retention.

Urinary retention without an identifiable urological cause presents a diagnostic and therapeutic challenge. Patients with nonobstructive chronic urinary retention usually have to rely on intermittent self-catheterization or indwelling suprapubic or transurethral catheters, which significantly affect quality of life. For some patients, however, sacral neuromodulation (SNM) offers an effective therapeutic alternative, and women with primary disorder of urethral sphincter relaxation (Fowler's syndrome) seem to respond particularly well to this treatment. Although the mechanism of action of SNM is not well understood and requires further investigation, it seems to involve afferent mediation of spinal cord reflexes and brain networks. The evolution of SNM devices and improvements in surgical and testing techniques, especially the introduction of the two-stage tined lead procedure, have considerably reduced the failure, adverse event and surgical revision rates associated with SNM, ensuring that this modality is an effective minimally invasive treatment for urinary retention.