Abstract
Aims: This study assesses the potential of epispinal (subdural) stimulation applicationin the treatment of urinary and bowel neurological disorders. Acute experiments wereperformed on a large animal model — the domestic pig — to develop a newmethodology facilitating future results and technology transfers to human.Methods: After rectal and bladder catheterization, four Landrace pigs (45-50 kg)underwent spinal cord surgery— that is, lumbosacral incision, laminectomy [L4-S4],dural opening and microsurgical arachnoid dissection. Three successive electricalstimulation sessions were carried out: 1) nerve roots stimulation, 2) epispinalstimulation with a matrix electrode, 3) epispinal stimulation with a small diameterneedle electrode. Changes in rectal and bladder pressures were monitored throughoutthe various procedures to identify spinal areas inducing responseswhile evaluating theinfluence of electrode contacts size in the measured responses amplitudes.Results: Aninteresting areawas identified in the upper portion of the spinal myelomeres(ie, spinal cord segment delimited by two successive pairs of spinal roots) directlyadjoining root with best pressures (either rectal or vesical). Significant responses (up to40 cmH2O) were also obtained with a needle electrode. Furthermore, bowel evacuationwas triggered in one of the animals. Despite the use of smaller electrode contacts, nodetrusor or rectum selective responses were observed in none of the sessions.Conclusion: This study showed, for the first time, that epispinal stimulation causessignificant detrusor and rectal responses in pigs and allows considering further studieswith the objective of treating urinary and rectal disorders in spinal cord injurypatients.