title: Diaphragm pacing after bilateral implantation of intradiaphragmatic phrenic stimulation electrodes through a transmediastinal endoscopic minimally invasive approach: pilot animal data.
abstract: OBJECTIVE
  Phrenic nerve stimulation for diaphragm pacing allows patients with central respiratory paralysis to be weaned from mechanical ventilation. Two procedures are available, either intrathoracic (bilateral thoracotomy) or intradiaphragmatic (four ports laparoscopy). The present experimental work assesses the feasibility, safety and efficacy of a trans-mediastinal implantation of intradiaphragmatic phenic nerve stimulation electrodes using a flexible gastroscope through a cervical incision.
  
  
  METHODS
  We operated on nine ewes. After selective bronchial intubation, we dissected the latero-tracheal space and opened both mediastinal pleura. We then introduced a flexible gastroscope into the pleural cavities, in a sequential manner. The phrenic nerves were located and followed up to the diaphragm dome. Electrodes loaded within a long, pliable needle were introduced through the adjacent intercostal space and implanted in each hemidiaphragm, at a 'tendinous' location (as close as possible to the entry of the nerve in the central tendon), and at a more lateral 'muscular' location. Postoperatively, the animals were ventilated using bilateral phrenic nerve stimulation. After euthanasia, abdominal verification of the electrodes position was performed through a laparotomy.
  
  
  RESULTS
  The mediastinal and pleural parts of the procedure were uneventful. The insertion of electrodes was associated with transdiaphragmatic puncture and small abdominal haematomas in the first two animals studied. After a slight modification of the insertion technique, this was not observed anymore. Phrenic nerve stimulation produced efficient ventilation, with tidal volumes significantly higher when delivered at the tendinous site than at the muscular site.
  
  
  CONCLUSIONS
  The trans-mediastinal implantation of intradiaphragmatic phrenic nerve stimulation electrodes is feasible, appears reasonably safe, and allows efficient ventilation.
authors.affiliation: Department of Thoracic Surgery, Assistance Publique - Hôpitaux de Paris, Tenon Hospital, Paris, France. jalal.assouad@tnn.aphp.fr
authors.forename: Jalal
authors.initials: J
authors.lastname: Assouad
authors.forename: Hicham
authors.initials: H
authors.lastname: Masmoudi
authors.forename: Jesus
authors.initials: J
authors.lastname: Gonzalez-Bermejo
authors.forename: Capucine
authors.initials: C
authors.lastname: Morélot-Panzini
authors.forename: Moustapha
authors.initials: M
authors.lastname: Diop
authors.forename: Dominique
authors.initials: D
authors.lastname: Grunenwald
authors.forename: Thomas
authors.initials: T
authors.lastname: Similowski
mesh_terms: D000818:Animals; D003964:Diaphragm / Q000294:innervation / Q000502:physiology*; D004599:Electric Stimulation Therapy / Q000379:methods*; D004567:Electrodes, Implanted; D004724:Endoscopy / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D010791:Phrenic Nerve; D010865:Pilot Projects; D012121:Respiration, Artificial / Q000379:methods; D012133:Respiratory Paralysis / Q000628:therapy; D034561:Sheep, Domestic; D015300:Ventilator Weaning / Q000379:methods*