Effects of withdrawal and re-application of spinal cord stimulation to restore cough.

Context: Paralysis of the expiratory muscles in cervical and high thoracic spinal cord injury (SCI) results in an impaired ability to clear airway secretions effectively and increases the risk of atelectasis and respiratory tract infections (RTI). Spinal cord stimulation (SCS) applied via the Cough Stimulation System (CSS) has been shown to restore an effective cough mechanism in subjects with SCI. In this study, we evaluated the specific impact of use of the CSS by one study participant with SCI, subsequent discontinuation of usage, and then re-institution of this modality. Airway pressure generation (P) and peak expiratory airflow rate (F) achieved with CSS and clinical assessment questionnaires were assessed.

Findings: With the CSS, this subject was able to generate P and F rates of 103 cmH₂O and 7.1 l/s, respectively, with associated significant clinical benefits, including, much greater ease in raising secretions and reduction in the incidence of RTIs. However, following a 2-year period of regular use, the CSS became non-functional and a 2-year period elapsed before it could be replaced. During this time, he again experienced great difficulty managing airway secretions and an increased frequency of RTIs. Re-institution of the CSS system resulted in the restoration of an effective cough mechanism and similar clinical benefits.

Conclusion/clinical relevance: This report demonstrates the very high degree of the clinical utility of the CSS as it had made a substantial beneficial impact on this participant's respiratory status and life quality.