Over thirty-eight spinal cord injury (SCI) and amyotrophic lateral sclerosis (ALS) patients have been successfully implanted with laparoscopically placed intramuscular diaphragm electrodes to pace and condition the diaphragm. A key element to surgical implementation of this low-risk, cost effective technique is electrical mapping of phrenic nerve motor points using laparoscopic instruments. With the emergence of natural orifice translumenal endoscopic surgical (NOTES) techniques, as an enabling technology, the success of the laparoscopic diaphragm stimulation could provide access to a larger population of SCI and ALS patients. This proposal focuses on advancing the state of the art of instruments to implement neurostimulation mapping techniques with a translumenal approach. Overall the proposed research is intended to advance ventilatory care for patients with respiratory insufficiency. The long-term goal of this technology is to: 1) develop translumenal mapping instrumentation and techniques, 2) develop electrode delivery techniques to minimize the surgical risks, 3) demonstrate the use of NOTES neurostimulation in ventilatory assist patients, and 4) support the development of further NOTES neurostimulation. The specific aims of this Phase 1 effort include the development of translumenal mapping instrumentation to: 1) accurately and repeatable stimulate the inferior surface of the diaphragm, 2) sense the transient pressure response to the applied stimulation to obtain a quantifiable measure of optimal stimulation sites, and 3) accurately place temporary marking on the diaphragm surface to facilitate insertion of percutaneous intramuscular electrodes at the optimal locations. According to the 2005 National SCI Database 21.2% (2,503) of all individuals with tetraplegia and 7.1% (748) of all individuals with paraplegia required a mechanical ventilator for pulmonary support during their initial rehabilitation admission. Inherent complications to mechanical ventilation are infection, tracheal injury and equipment malfunction. Ventilator-associated pneumonia is a common occurrence among patients with prolonged use of an artificial ventilator; pneumonia is the most common cause of death after spinal cord injury. Likewise, 84% of deaths in ALS are related to respiratory failure. Most ALS patients choose death rather than mechanical ventilation. Development of NOTES diaphragm stimulation will provide clinicians with tools to reduce risks associated with the positive pressure mechanical ventilation and costs. Further complications of mechanical ventilation which may be addressed by this technology include diaphragm atrophy, barotrauma, posterior lobe atelectasis, and impaired hemodynamics which are normally improved by maintaining a more natural negative chest pressure. Successful realization of this technology has a significant value proposition for the patients and healthcare providers and therefore substantial commercial potential. This project proposes the development of a novel diagnostic endoscopic neurostimulation device using Natural Orifice Translumenal Endoscopic Surgery (NOTES) techniques. The first intended application of the device is to reduce the risks and costs associated with implementation of a diaphragm pacing stimulation system.
