Referred shoulder pain (C4 dermatome) can adversely impact diaphragm pacing with intramuscular electrodes.

Diaphragm pacing is an alternative to mechanical ventilation in patients with high cervical cord damage (>C4 dermatome). It brings clinical benefits and reduces health costs [1–3]. It is also indicated in certain cases of central hypoventilation [4]. Two types of diaphragm pacing devices are commercially available. With intrathoracic phrenic stimulation, electrodes are implanted around the phrenic nerves in the thorax (Avery Biomedical, Commack, NY, USA; and Atrotech, Tampere, Finland). Nerve dissection during a video-assisted mini-thoracotomy allows intimate contact of the stimulating electrodes with the nerve [5]. Stimulating currents typically range between 0.3–3.5 mA [6]. With intradiaphragmatic stimulation, hook wire electrodes are laparoscopically implanted in the diaphragm in the vicinity of the phrenic nerve termination (Synapse Biomedical, USA) [in 5]. Stimulating currents typically range between 5–20 mA. In quadriplegic patients, intradiaphragmatic phrenic stimulation is effective [7] and has been advocated as easier to implement and less expensive than its intrathoracic counterpart [5]. In patients who retain spontaneous diaphragm activity, this approach is appealing because it is devoid of the theoretical risk of procedure-induced phrenic nerve damage associated with the intrathoracic route. For these reasons, we implanted intradiaphragmatic phrenic stimulators in four hypoventilation patients after the device was authorised in France in 2010. In France, both intrathoracic and intradiaphragmatic diaphragm pacing are authorised and reimbursed by social security in quadriplegia and central hypoventilation and are managed at a single multidisciplinary centre nationwide.