Comparison of disc and wire electrodes to restore cough via lower thoracic spinal cord stimulation

Abstract

Objective

To compare the safety and effectiveness of wire (WE) vs. disc (DE) electrodes to restore cough in subjects with spinal cord injury (SCI).

Design

Clinical trials assessing the effectiveness and clinical outcomes associated with two electrode systems to activate the expiratory muscles.

Setting

Inpatient hospital setting for DE or WE electrode insertion; outpatient evaluation of cough efficacy and instructions for home use.

Participants

Twenty-nine subjects with SCI; 17 participants with DE and 12 with WE implants.

Intervention

Surgical implantation of WE or DE to restore cough. Daily application of spinal cord stimulation (SCS) at home.

Main outcome measure(s)

Airway pressure (P) and peak airflow (F) generation achieved with SCS; clinical parameters including ease in raising secretions, incidence of acute respiratory tract infections (RTI) and side effects.

Results

P and F achieved with DE and WE were not significantly different. For example, at total lung capacity (TLC) with participant effort, P was 128 ± 12 cmH₂O and 118 ± 14 cmH₂O, with DE and WE, respectively. The degree of difficulty in raising secretions improved markedly in both groups. The incidence of RTI per year fell from 1.3 ± 0.3 and 1.3 ± 0.5–0.3 ± 0.1 and 0.1 ± 0.1 for DE and WE groups, respectively (P < 0.01 for both when compared to pre-implant values and NS between DE and WE groups). The only significant side effect i.e. short-term autonomic dysreflexia was also similar between groups.

Conclusions

The results of this investigation indicate that both DE and WE result in comparable degrees of expiratory muscle activation, clinical benefits and side effects. Importantly, SCS to restore cough can be achieved with use of WE which can be placed using minimally invasive techniques and associated reduction in cost, surgical time and overall risk.

Trial registration: ClinicalTrials.gov identifier: NCT00116337., NCT01659541, FDA IDE: G980267

Keywords:

• Spinal cord injury
• Tetraplegia
• Cough
• Respiratory muscles
• Rehabilitation

Acknowledgements

The authors gratefully acknowledge the surgical assistance of Dr. Kutaiba Tabbaa, MD and statistician Charles Thomas, B.A.

Disclaimer statements

Contributors None.

Funding This work was supported by the National Institute of Neurological Disorders and Stroke [Grant Numbers R01 NS049516 and U01 NS083696], Neilson Foundation [Grant Number 278855], NCRR [Grant Numbers M01RR000080 and UL1RR024989]. This project was supported by the Clinical and Translational Science Collaborative (CTSC) of Cleveland which is funded by the National institutes of Health (NIH), National Center for Advancing Translational Science (NCATS), Clinical and Translational Science Award (CTSA) [Grant number UL1TR002548]; National Center for Research Resources

Conflicts of interest Dr. DiMarco holds two United States Patents for technology related to the content of this paper: Method and Apparatus for Electrical Activation of the Expiratory Muscles to Restore Cough (5,999,855); Bipolar Spinal Cord Stimulation to Activate the Expiratory Muscles to Restore Cough (8,751,004). This investigation was approved by the Institutional Review Board of MetroHealth Medical Center (IRB98-00091 and RB15-00014).