Neuromodulation : journal of the International Neuromodulation Society
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The purpose of this paper is to discuss which nerve fibers in the various quadrants of the spinal cord are immediately activated under normal conditions of spinal cord stimulation, ie, at voltages within the therapeutic range. The conclusions are based on both empirical and computer modeling data. The recruitment of dorsal column (DC) fibers is most likely restricted to Aβ fibers with a diameter ≥ 10.7 μm in a 0.20-0.25 mm layer under the pia mater and fibers of 9.4-10.7 μm in an even smaller outer layer when a conventional SCS lead is used. ⋯ The latter are presumably of proprioceptive origin and responsible for segmental reflexes and uncomfortable sensations. Furthermore, it is shown to be unlikely that, apart from dorsal roots and a thin outer layer of the DCs, any other spinal structures are recruited when stimulation is applied in the dorsal epidural space. Finally, anodal excitation and anodal propagation block are unlikely to occur with SCS.
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Percutaneous retrograde lead insertion for sacral nerve root stimulation is a newly described technique being applied to a variety of pain disorders. The success of the procedure rests in a defined epidural space such that there is unimpeded progression of the lead into the desired location. It is hypothesized that any condition that results in anatomic compromise of the epidural space would prevent the success of the procedure. ⋯ In another patient, repeated attempts at passing the epidural lead distal to the congenital defect were unsuccessful, and the percutaneous procedure was aborted. In conclusion, we have found that the diagnosis of spina bifida occulta, or any other condition in which the epidural space is anatomically disrupted, is a relative contraindication for this procedure. Preoperative roentograms of the lumbar spine may be helpful in avoiding technical difficulties due to this diagnosis.
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The aim of this work is to assess quality of treatment and to monitor drawbacks of SCS implantation systems through a National Observational Center. Data were obtained through a questionnaire sent by post or via telephone to each patient. All patients were affected by chronic-'vascular' and "neuropathic" pain. ⋯ We conclude that the methodology used is consistent with that of previous studies on nonmalignant chronic pain. The data obtained also reveal implantation hardware reliability, regardless of clinical outcome. A low percentage of complications and a high degree of patient satisfaction are also to be stressed.