Neuromodulation : journal of the International Neuromodulation Society
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The objective of this study was to compare the technical performance of laminectomy and percutaneous spinal cord stimulation leads with similar contact spacing by computer modeling. Monopolar and tripolar (guarded cathode) stimulation with both lead types in a low-thoracic spine model was simulated using UT-SCS software. Dorsal column and dorsal root fiber thresholds were calculated as well as the area of recruited fibers in the dorsal columns, the rostrocaudal span of recruited dorsal root fibers and the energy consumption at discomfort threshold. ⋯ A deterioration of all performance parameters is predicted when a percutaneous lead is placed more dorsally in the epidural tissue. When positioned next to the dura mater, a percutaneous lead has a similar performance (fiber recruitment in the dorsal columns and the dorsal roots) as a laminectomy lead with similar contact spacing, but substantially higher energy consumption. The superior clinical performance of the laminectomy lead is most probably due to the difference in volume and insertion technique of the two lead types.
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The objective of this study was to evaluate the stimulation responses on each channel of an implantable two-channel stimulator that stimulates the peroneal nerve branches innervating the muscles for dorsiflexion and eversion movements. Currently five Dutch patients and five English patients have been implanted with this system. Isometric ankle torque measurements were carried out in the patient with the longest follow-up period (1 y). ⋯ Eversion moments are determined mainly by channel 2 and to a lesser extent by channel 1. Both channels determined abduction/adduction moments. We conclude that stimulation responses in both dorsiflexion and eversion direction can be set individually and with great accuracy and are reproducible over a prolonged period.