Neuromodulation : journal of the International Neuromodulation Society
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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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Since their initial development, the performance gains in functional electrical stimulation (FES) systems have been modest. Conceptually, the replacement of normal neural function by artificial electronic systems is attractive, considering the continued technologic advancements in electronics, communication, and control. It is likely that efficacious FES systems will require complete implantation and activation of large numbers of motor units. ⋯ While an engineer might be pleased to design a system that functions, as intended, 99% of the time, if a user falls down 1 time out of every 100, this is likely to be unacceptable. The minimal threshold of functional utility for FES systems is unclear, and will not be addressed here. Rather, we consider the issues of what features and capabilities are desirable for next generation implantable systems, and to what degree these desires approach engineering feasibility.