Long-term follow-up of spinal cord stimulation to restore cough in subjects with spinal cord injury

Objective: To determine the long-term effects of the cough stimulation system. Design: Nonrandomized clinical trial of subjects using the study device well beyond the period of close follow-up. Setting: Use of the study device in the home setting. Participants: Subjects (N = 10) implanted with the device for a minimum of 2 years (mean 4.6 +/- 0.6 years). Interventions: Application of daily stimulation. Outcome measures: Airway pressure generation and other clinical assessments including ease in raising secretions, life quality, caregiver support, and incidence of respiratory tract infections were measured at 1 year and mean 4.6 years after implantation. Results: Each subject continued to use the device on a regular basis. During SCS, mean maximum airway pressures were 103.1 +/- 20.4 and 107.7 +/- 23.0 cmH(2)O at the 1-year and mean 4.6-year follow-up points, respectively (P < 0.05 compared with pre-implant and not significantly different (NS) compared with 1-year follow-up). Benchmarks related to ease in raising secretions and improvements in life quality related to respiratory care were maintained at the mean 4.6 year follow-up. The need for trained caregivers to provide other means of secretion management remained significantly below the pre-implant values (P < 0.05). The incidence of acute respiratory tract infections remained low at 0.2 +/- 0.1 events/year, which is significantly below the pre-implant value of 1.4 +/- 0.3 events/year (P < 0.05). Conclusion: Subjects continued to use the system on a long-term basis beyond the period of close follow-up and to continued derive significant clinical benefits.