ABSTRACT: 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.
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.
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.
The trans-mediastinal implantation of intradiaphragmatic phrenic nerve stimulation electrodes is feasible, appears reasonably safe, and allows efficient ventilation.
European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 03/2012; 42(2):333-9. · 2.40 Impact Factor
ABSTRACT: Diaphragm pacing by phrenic nerve (PN) stimulation is currently used for patients with central respiratory paralysis to be weaned from mechanical ventilation. Electrodes are inserted either through bilateral thoracotomy or through four ports laparoscopy. The aim of this experimental work is to demonstrate the feasibility of trans-mediastinal bilateral implantation of PN electrodes using a flexible gastroscope introduced through a cervical incision in human cadavers.
Ten refrigerated and non-embalmed cadavers were used. The gastroscope was introduced through a cervical incision into the latero-tracheal space and then subsequently into both pleura by opening the mediastinal pleura. After identification of the PN, electrodes were introduced through an intercostal space to the desired diaphragmatic location using a long, pliable needle with the electrode loaded in its lumen.
Results are described for each hemi-diaphragm not for an anatomic subject. Mediastinal exploration and introduction of the video gastroscope into the pleural cavities proved easy in all subjects. Pleural adherences were present in five hemi-diaphragms. The central tendon of both hemi-diaphragms could be identified unambiguously in all the subjects. Identification of the entry point of the phrenic nerve into the diaphragm was straightforward in 10 hemi-diaphragms. In the remaining 10, this proved more difficult because of mediastinal fat or lung parenchyma. Introduction of the electrode-holding needles through the intercostal space and their insertion close to the phrenic nerve entry point was also easy. Withdrawal of the needle from the diaphragm and 'capture' of the hook were successful on the first attempt in 14 hemi-diaphragms, but failed in six others in whom a second attempt was necessary.
Trans-mediastinal implantation of PN stimulation electrodes is possible using a flexible endoscope. This application of endoscopic surgery could allow a minimally invasive placement of PN electrodes in patients with central respiratory paralysis, for example, at the time of tracheostomy.
European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 08/2011; 40(4):e142-5. · 2.40 Impact Factor
ABSTRACT: Osseous metastases of renal cell carcinoma (RCC) are the second most frequent location after lung metastases. They rarely present as isolated location. When isolated, resection may offer five-year survival rates of 30-60%. The purpose of the current study is to focus on a particular subset, the isolated rib metastases (IRM). The files of six patients who underwent radical resection for IRM were reviewed. All had previous radical nephrectomy for clear-cell renal cancer. The mean age of these six men was 55.3 years. Preoperative evaluation included in all patients a conventional chest radiograph and thoracic computed tomography (CT) scanning. Chest wall resections were wide and curative. The mean disease-free interval (DFI) after renal cancer treatment was 25 months. There was no postoperative death. Two patients had synchronous disease. One of them developed two recurrences operated on by large resections. They survived for 77 and 81 months. The overall five and ten-year survival rates were respectively, 83 and 66.7%. IRM of RCC are rare and remain not well-known. Surgical wide resection is a safe and effective treatment.
Interactive cardiovascular and thoracic surgery 10/2009; 10(2):172-5.