Pharmacological treatment is the first option in the case of a hyperactive bladder. If such treatment proves unsatisfactory or generates unacceptable adverse side effects, the LION procedure is implemented. Electrostimulation, a method to stimulate nerves by implanted electrodes, has been known for a long time. It has a beneficial effect on lower urinary tract symptoms and on the perception of pain in the small pelvis. The goal of sacral neuromodulation is to reduce the symptoms by retuning vesical and intestinal functions. It is essentially used to treat vesical hyperactivity, female urinary retention and vesical and intestinal atonia. Based on different observations, neuromodulation also appears to be beneficial in patients suffering from miction disturbances of neurological origin, such as multiple sclerosis, spinal cord lesions and painful chronic cystitis.

In the United States, treatment of urgency incontinence by sacral neuromodulation was authorized in 1997. In 1999, this authorization was extended to include urinary retention. The neuromodulator of sacral roots is normally implanted through the skin. A multipolar electrode consisting of four independent stimulation electrodes is introduced through the sacral orifice under local anaesthesia and positioned under radiological guidance as close as possible to the sacral nerve roots. The fact that the electrode needle is implanted blindly (in the absence of direct visual control) is one of the shortcomings of this method. Thus, a lack of response to the treatment may mean that either the neuromodulation was unsuccessful or the electrode was simply inserted too far from the nerve. To minimize this potential source of error, a quadripolar electrode is used. At the same time, the advantage of applying the LION procedure to sacral nerves resides in the fact that a single electrode may be in contact with all the sacral roots involved in the control of the bladder, the intestine and the sphincters.