title: 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.
  
  
  METHODS
  Animal study.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Dogs (n = 8).
  
  
  METHODS
  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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: Krysztof E
authors.initials: KE
authors.lastname: Kowalski
authors.forename: Anthony F
authors.initials: AF
authors.lastname: DiMarco
mesh_terms: D000399:Air Pressure; D000818:Animals; D001864:Bone Wires; D004285:Dogs; D004558:Electric Stimulation / Q000379:methods; D007403:Intervertebral Disc / Q000502:physiology*; D019736:Prostheses and Implants; D012132:Respiratory Muscles / Q000502:physiology*