Sacral anterior root stimulator

An implantable medical device enabling patients with a spinal cord lesion to empty their bladders.

History
From 1969 onwards Brindley developed the sacral anterior root stimulator, with successful human trials from the early 1980's onwards. Early attempts were confounded by the fact that the nerve roots that supply both the bladder and sphincter muscles would contract simultaneously on stimulation, cancelling each other's effect.

Description
This device is implanted over the sacral anterior root ganglia of the spinal cord; controlled by an external transmitter, it delivers intermittent stimulation which improves bladder emptying. It also assists in defecation and enables male patients to have a sustained full erection.

The related procedure of sacral nerve stimulation is for the control of incontinence in otherwise able-bodied patients.