Comparison of wire and disc leads to activate the expiratory muscles in dogs

Abstract

Objective: Respiratory complications account for a major cause of morbidity and mortality in subjects with spinal cord injury (SCI) due to paralysis of the expiratory muscles and the consequent inability to generate effective cough. We demonstrated previously that effective cough can be restored in SCI via spinal cord stimulation (SCS) with disc leads positioned on the lower thoracic and upper lumbar spinal cord via laminotomy incisions. In this study, the effectiveness of wire leads, which can be placed using minimally invasive techniques, to activate the expiratory muscles was evaluated. Design: Animal study. Setting: Research laboratory. Animals: Dogs (n = 8).Interventions: In separate trials, disc and wire leads were inserted onto the dorsal epidural space at the T9, T11, and L1 spinal cord levels. Effects of electrical stimulation with disc, single wire, and two wire leads placed in parallel were compared. Outcome measures: Airway pressure generation following stimulation with disc and various configurations of wire leads were compared. Results: Several different configurations of wire leads resulted in airway pressures that were similar to those generated with monopolar stimulation with disc leads (MSDLs). For example, combined monopolar stimulation with parallel wire leads at the T9 + T11 and T9 + L1 levels resulted in airway pressures that were 103.5 ± 6.4 and 101.9 ± 7.0%, respectively, of those achieved with MSDL. Bipolar stimulation with parallel wire leads at T9-T11 and T9-L1 resulted in airway pressures that were 94.2 ± 3.4 and 96.8 ± 5.0%, respectively, of the pressures achieved with MSDL. Other wire configurations were also evaluated, but were generally less effective. Conclusion: These results suggest that specific configurations of wire leads, which can be placed via minimally invasive techniques, result in comparable activation of the expiratory muscles compared to disc leads and may be a useful technique to restore cough in persons with SCI.

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

“…Recent studies performed in animals, however, suggest that electrode placement can also be accomplished using wire lead technology. 14 The significant advantage of these types of leads is that they can be inserted percutaneously via minimally invasive techniques through a needle. It should be noted that the placement of spinal cord stimulators using wire leads for control of pain is already commonplace and has been in clinical use for more than 2 decades.…”

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

“…Based upon recent animal studies, large positive airway pressures and peak airflow rates, in the same range as those achieved with the disc electrodes, can be achieved with wire electrodes. 32,33 These electrodes can be inserted with very small incisions and performed on an outpatient basis resulting in substantial cost savings, compared to the disc electrodes used in the present study. Use of minimally invasive techniques would bring the break-even point well within the first year of use by reducing costs of operating room and anesthesia services and eliminating hospital bed charges (estimated reduction of ~$20,000).…”

Use of electromyographic signals for characterization of voluntary coughing in humans with and without spinal cord injury—A systematic review

“…However, some clinical conditions, such as the spinal cord injury (SCI), may alter the neuromotor physiology of coughing and contribute to the emergence of respiratory dysfunctions, due to the inability of respiratory muscles to generate efficient contractions (Dicpinigaitis, Grimm, & Lesser, ; Kowalski & Dimarco, ). In this condition, the motor level of the spinal cord lesion can determine the functional state of the SCI, that is, which motor functions are intact and which were partially or completely lost.…”

“…During a cough, the expiratory muscles contract in a synchronic way, causing the rise of the intra-abdominal pressure and, consequently, the increase in the peak expiratory flow (Mccool, 2006) and the peak cough flow (Cardoso et al, 2012;Chan, Jones, Chung, & Hung, 2010;Kang, Kang, Sohn, Park, & Moon, 2006). However, some clinical conditions, such as the spinal cord injury (SCI), may alter the neuromotor physiology of coughing and contribute to the emergence of respiratory dysfunctions, due to the inability of respiratory muscles to generate efficient contractions (Dicpinigaitis, Grimm, & Lesser, 1999;Kowalski & Dimarco, 2011). In this condition, the motor level of the spinal cord lesion can determine the functional state of the SCI, that is, which motor functions are intact and which were partially or completely lost.…”