The main trial intervention of this study will be the implantation of one rechargeable neurostimulator instead of the currently used non-rechargeable neurostimulator(s) and surgical closure of one of the existing abdominal wall cavities (the so‐called "pockets"). It may be necessary to tunnel the extension cable from one side to another within the thoracic or abdominal wall. Thereby, we may provoke extension cable loops which may provoke undesirable stimulation when passing through a magnetic field. However this risk seems smaller than the risk of dissecting the electrode and replacing the extension cable to the other side.