Neuromodulation : journal of the International Neuromodulation Society
-
Objectives. Although the load impedance of a pulse generator has a significant effect on battery life, the electrical impedance of contact arrays in spinal cord stimulation (SCS) has not been extensively studied. We sought to characterize the typical impedance values measured from common quadripolar percutaneous SCS contact arrays. Methods. In 36 patients undergoing percutaneous trial stimulation for various chronic pain conditions, bipolar impedance between adjacent contacts of 64 leads with 9 mm center-to-center spacing was measured in two different vertebral level regions, cervical (C3-C7) and lower-thoracic (T7-T12). ⋯ Conclusions. Results from finite-difference mathematical modeling of SCS suggest that the difference in tissue impedance related to vertebral level may be due to the dorsoventral position of the lead in the epidural space. The presence of a larger space between the triangularly shaped dorsal part of the vertebral arch and the round shape of the dural sac in the lower-thoracic region increases the likelihood that the stimulating lead will not make dural contact, and thus "see" an increased impedance from the surrounding epidural fat. This implies that the energy requirements for stimulation in the thoracic region will be higher than in the cervical region, at least during the acute phase of implant.
-
Clinical neurophysiology has always played an important interventional role throughout the perioperative stages in functional neurosurgery. On the one hand, some neurophysiologic procedures have become an integrated part of neurosurgery. On the other hand, in deep brain stimulation, although the surgical electrode implantation is an essential step, the therapeutic effects are actually produced by electrically modulating the physiologic activity of the brain. We review the topic of neurophysiologic intervention in the deep brain stimulation for movement disorders by presenting the evidence derived from our own experiences based on an integrated group located at two hospitals in London and Oxford, UK, and mainly covering tremor caused by multiple sclerosis, Parkinson's disease and dystonia.
-
Objectives. To determine whether deep brain stimulation is an effective treatment for neuropathic pain of varied etiology. Material and Methods. Thirty-four patients with intractable neuropathic pain were prospectively studied using visual analog scores, McGill Pain Questionnaire, and Quality of Life Questionnaires (EUROQOL EQ-5D VAS, and SF-36 v-2). Patients had either deep brain stimulation of either the periventricular gray or ventroposterolateral nucleus of the thalamus, or both. ⋯ Health-related quality of life improved by 38%. Conclusions. Deep brain stimulation is an effective treatment for neuropathic pain. The factors that influence outcome, including etiology and site of stimulation, are discussed.
-
Objectives. To investigate feasibility and safety of implant-driven tibial nerve stimulation. Materials and Methods. Eight patients with refractory overactive bladder were successfully treated with implanted percutaneous tibial nerve stimulation (PTNS). Patients were evaluated with bladder diaries, quality of life questionnaires, and physical examination before implantation, and at 3, 6, and 12 months of follow-up. ⋯ At 3- and 6-month follow-up, voiding and quality of life parameters had significantly (p < 0.05) improved. Urinary tract infection, temporarily walking difficulties, and spontaneous radiating sensations were reported as adverse events and no local infection, erosion, or dislocation. Conclusions. Implant-driven tibial nerve stimulation seems to be feasible and safe.