Lower thoracic spinal cord stimulation to restore cough in patients with spinal cord injury: results of a National Institutes of Health-Sponsored clinical trial. Part II: clinical outcomes

Abstract

Objective: To evaluate the clinical effects of spinal cord stimulation (SCS) to restore cough in subjects with cervical spinal cord injury.

Design: Clinical trial assessing the clinical outcomes and side effects associated with the cough system.

Setting: Outpatient hospital or residence.

Participants: Subjects (N=9; 8 men, 1 woman) with cervical spinal cord injury.

Interventions: SCS was performed at home by either the subjects themselves or caregivers on a chronic basis and as needed for secretion management.

Main outcome measures: Ease in raising secretions, requirement for trained caregiver support related to secretion management, and incidence of acute respiratory tract infections.

Results: The degree of difficulty in raising secretions improved markedly, and the need for alternative methods of secretion removal was virtually eliminated. Subject life quality related to respiratory care improved, with subjects reporting greater control of breathing problems and enhanced mobility. The incidence of acute respiratory tract infections fell from 2.0+/-0.5 to 0.7+/-0.4 events/subject year (P<.01), and mean level of trained caregiver support related to secretion management measured over a 2-week period decreased from 16.9+/-7.9 to 2.1+/-1.6 and 0.4+/-0.3 times/wk (P<.01) at 28 and 40 weeks after implantation of the device, respectively. Three subjects developed mild hemodynamic effects that abated completely with continued SCS. Subjects experienced mild leg jerks during SCS, which were well tolerated. There were no instances of bowel or bladder leakage.

Conclusions: Restoration of cough via SCS is safe and efficacious. This method improves life quality and has the potential to reduce the morbidity and mortality associated with recurrent respiratory tract infections in this patient population.

Trial registration: ClinicalTrials.gov NCT00116337.

Figure 1

Subject responses to frequency of need for conventional means of secretion clearance, severity of cough episodes, difficulty in raising secretions, need for aerosol bronchodilator medications and ease in raising sputum. With the exception of need for bronchodilator medication, there were significant improvements in all other parameters of secretion management at week #28. This improvement was maintained at week #40.

Figure 2

Subject responses to life quality assessment related to secretion management. There was significant improvement in most parameters at week #28 and week #40 (p < 0.01). Improvements in overall health and life quality, however, were not statistically significant.

Figure 2

Subject responses to life quality assessment related to secretion management. There was significant improvement in most parameters at week #28 and week #40 (p < 0.01). Improvements in overall health and life quality, however, were not statistically significant.

Figure 3

There were significant reductions in the need for caregiver support (upper panel) and significant reductions in the incidence of acute respiratory tract infections (lower panel) following use of the cough system. See text for further explanation.