Sacral nerve stimulation (SNS) implant. Artwork of the sacral region of a woman's pelvis showing a schematic symbol for a sacral nerve stimulator. SNS delivers an electrical impulse to stimulate the sacral nerve as a treatment for those with bladder control problems. The bladder (not shown) stored urine produced by the kidneys (shown at left). It is thought that the impulse from SNS facilitates communication between the brain and bladder, helping to relieve the symptoms of urinary retention or an over-active bladder. The bottom five vertebrae (the lumbar vertebrae) are also labelled (I-V).