Background: Diaphragm movement is essential for adequate ventilation and when the diaphragm is adversely affected patients face life long positive pressure mechanical ventilation or death. This report summarizes the complete world wide multi-center experience with the diaphragm pacing stimulation (DPS) system to maintain and provide diaphragm function for ventilation.
Methods: In prospective FDA trials, patients underwent laparoscopic diaphragm motor point mapping to identify the area where maximum diaphragm contraction occurs when the implanted electrode is stimulated. The adverse events and operative experience were recorded and analyzed.
Results: From March of 2000 to September of 2007, a total of 88 patients(44 patients in 2007 alone) were implanted with the DPS system at 5 sites for the following indications spinal cord injury (SCI) (48), Amyotrophic Lateral Sclerosis (ALS) (38), and transverse myelitis (2). Patient age ranged from 18-74 and time from SCI to implantation ranging from 3 months to 27 years. In 87 patients the diaphragm motor point was mapped with successful implantation of electrodes with the only failure the second patient due to a false positive phrenic nerve study. There was no peri-operative mortality even in ALS patients with forced vital capacity (FVC) below 50% predicted. The most common tracked adverse event (42% of SCI patients) was a capno-thorax were the CO2 tracked to the pleural space from electrode implantation in the thinned deconditioned diaphragm. Average time in the operating room was less than 120 minutes with no differences between sites. There was no cardiac involvement from diaphragm pacing even when analyzed in 10 of the patients who had pre-existing cardiac pacemakers. No infections occurred even with simultaneous gastrostomy tube placements for ALS patients with bulbar symptoms and dysphasia. Average hospital stay was less than 24 hours. In the SCI patients 96% were able to use the DPS system to provide ventilation and in the ALS studies patients have been able to delay the need for mechanical ventilation up to 20 months.
Conclusion: This multi-center experience has shown that laparoscopic diaphragm motor point mapping, electrode implantation and pacing can be safely performed. The ability to move the diaphragm for ventilation or maintain diaphragm function has significant patient benefit and is the basis for continued multi-center trials for additional indications.
Session: Podium Presentation
Program Number: S080