Case report: Minimally invasive method to activate the expiratory muscles to restore cough.

CONTEXT: Spinal cord stimulation (SCS) via disc electrodes surgically placed via laminotomy incisions has been shown to restore an effective cough in subjects with spinal cord injury (SCI). The purpose of this study was to evaluate a new method of expiratory muscle activation utilizing spinal cord wire leads, which can be implanted with minimally invasive techniques. METHODS: In a subject with SCI, parallel wire leads with two electrode contacts were inserted percutaneously through a needle, advanced to the T9, T11 spinal levels and connected to an implanted radiofrequency receiver. Stimulus parameters were set at values resulting in near maximum airway pressure generation (Paw) (40V, 50Hz, 0.2ms). Paw was measured at functional residual capacity (FRC) and total lung capacity (TLC) as an index of expiratory muscle strength. RESULTS: Paw during spontaneous efforts was 20 cmH2O (8.6% predicted). Bipolar (T9-T11) SCS resulted in Paw of 84 and 103 cmH2O, at FRC and TLC respectively. Monopolar (T9 only) SCS resulted in Paw of 61 and 86 cmH2O, at FRC and TLC respectively. This subject experienced much greater ease in raising secretions with use of SCS and no longer required other methods of secretion management. CONCLUSION: SCS via wire leads, which can be implanted using minimally invasive techniques, may provide a new useful method to restore an effective cough and possibly reduce the morbidity and mortality associated with respiratory tract infections in patients with SCI.

Economic Consequences of an Implanted Neuroprosthesis in Subjects with Spinal Cord Injury for Restoration of an Effective Cough.

Objective: To determine if an implanted neuroprosthesis for restoration of an effective cough is less costly than conventional methods of respiratory management. Methods: Nonrandomized clinical trial of participants (N = 14) with spinal cord injury (SCI) using the Cough Stimulator device in the inpatient hospital setting for Cough Stimulator implantation and outpatient hospital or residence for follow-up. A neuroprosthesis was implanted for restoration of an effective cough. The annual costs associated with respiratory management, without (pre implantation) and with (post implantation) the neuroprosthesis, were examined over a 4-year period. Results: The total cost related to implantation of the Cough Stimulator was $59,891, with no maintenance costs over subsequent years. The incidence of respiratory tract infections and the need for caregiver support fell significantly following implantation. The costs associated with respiratory tract infections fell significantly from a mean of $36,406 ± 11,855/year to $13,284 ± 7,035/year (p < .05) pre and post implantation, respectively. Costs fell further to $8,817 ± 5,990 and $4,467 ± 4,404 following the 2nd and 3rd years post implantation (p < .05), respectively. The costs associated with caregiver support fell significantly from $25,312 ± 8,019/year to $2,630 ± 2,233/year (p < .05) pre and post implantation, respectively, and remained low in subsequent years (p < .05). Other costs related to secretion management fell significantly and remained low in subsequent years (p < .05). Break-even analysis demonstrated that this point was reached in the first year. Conclusion: The results of this investigation demonstrate that implantation and use of the Cough Stimulator resulted in significant reductions in the overall costs of respiratory management in this patient population.