Neuromodulation : journal of the International Neuromodulation Society
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Baseline and 12-month follow-up data from a prospective controlled study on patients treated with SCS for neuropathic limb pain (NLP) are analyzed critically. The outcome on pain, use of medication, and quality of life are reported and compared with the literature. Patients enrolled from April 1999 to December 2001 were part of a quality system study by the Dutch Working Group on Neuromodulation. ⋯ The difference between baseline and 12-m follow-up is statistically significant for all measures. We conclude that the outcome measures indicate that SCS significantly reduces pain and enhances quality of life in patients having NLP not responding to other adjuvant therapy. Recommendations are proposed to make studies more comparable.
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The objective of this study was to develop and test the feasibility of a model that employs electromyographic (EMG) signals to predict the occurrence of gait events in the child with cerebral palsy (CP). This model could be the basis of a future functional electrical stimulation (FES) control system to assist gait. Two children were implanted with bifilar intramuscular electrodes into the quadriceps muscle bilaterally. ⋯ For nine of the 10 gait events evaluated, the model predicted gait events to within 82 ms on average, as referenced to the VICON motion analysis system. For eight of the 10 events, prediction errors were 0.3% or less. Results indicate that EMG from the proximal musculature could be used to predict the occurrence of gait events in these two children with CP.
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This study investigated the activation dynamics of electrical stimulation-evoked muscle contractions performed by individuals with spinal cord injury (SCI). The purpose was to determine whether electrical stimulation (ES) firing patterns during cycling exercise should be altered in response to fatigue-induced changes in the time taken for force to rise and fall with ES. Seven individuals with SCI performed isometric contractions and pedaled a motorized cycle ergometer with stimulation applied to the quadriceps muscles. ⋯ Cycling power output fell approximately 50% during the five minutes of exercise, however, there was no change in the time taken for torque to rise or fall. The magnitude of ES-evoked muscle torques decline substantially with fatigue, however, the overall pattern of torque production remained relatively unchanged. These results suggest there is no need to alter stimulation firing patterns to accommodate fatigue during ES-evoked exercise.
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Ever since its initial development in the late 1960s, spinal cord stimulation (SCS) has been used to treat a number of painful conditions. European practice, in contrast to that in North America, has used peripheral arterial disease (PAD) as a primary indication for SCS. First employed in patients with PAD in 1976, SCS was shown by Cook et al. to heal chronic leg ulcers. ⋯ Recent randomized prospective studies have questioned some of the conclusions from these preceding retrospective data. In addition to the questions related to outcomes, theories regarding exact mechanisms by which SCS improves circulatory parameters remain unclear. A thorough Medline literature review on the subject of SCS in peripheral vascular disease was thus undertaken to attempt to clarify questions regarding which patients are best suited for SCS therapy, pinpoint possible methodologic flaws in previous studies, and to review the background, outcomes, mechanisms of action, complications, and alternatives for SCS in patients with PAD.
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The objective of this study was to investigate di-acetyl morphine as an alternative opioid analgesic for use in implanted intrathecal drug delivery systems because of its greater solubility through evaluation of its stability in vivo and analgesic efficacy in the period between pump refills. Contents of intrathecal drug delivery system reservoirs (SynchroMed, Medtronic, Inc., Minneapolis, MN) that had been filled with di-acetyl morphine dissolved in saline (21), bupivacaine (9), or in both bupivacaine and clonidine (19) were sampled in vivo between 1 and 125 days after refill. The samples were assayed for di-acetyl morphine and its breakdown products by micellar electrokinetic capillary chromatography. ⋯ Mono-acetyl morphine decayed to morphine with a maxima estimated at 125 days. There was no clinically significant change in average weekly pain scores for up to ten weeks in either group (range, 2.5 to 2.8 for diamorphine and 2.7 to 3.1 for morphine) (2-way repeated ANOVA, F(9,220) = 0.98, n.s.). We conclude that di-acetyl morphine and its breakdown products, 6 mono-acetyl morphine and morphine, provide similar analgesia to morphine alone when administered by intrathecal pump for a period of at least ten weeks and may be a useful alternative when a more soluble agent is favored.