Neuromodulation : journal of the International Neuromodulation Society
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Objective. The safety and efficacy of intrathecal (IT) ziconotide was studied in a randomized, double-blind, placebo-controlled trial. Materials and Methods. Patients (169 ziconotide, 86 placebo) with severe chronic nonmalignant pain unresponsive to conventional therapy and a visual analog scale of pain intensity (VASPI score) ≥ 50 mm were treated over a 6-day period in an inpatient hospital setting. Initial starting dose was 0.4 µg/hour and was titrated to analgesia or intolerance (maximum dose 7.0 µg/hour). ⋯ During the initial titration phase, a significantly greater percentage of patients in the ziconotide group compared to the placebo group reported AEs, including abnormal gait, amblyopia, dizziness, nausea, nystagmus, pain, urinary retention, and vomiting. Conclusion. Ziconotide provided significant analgesia in patients for whom conventional therapy failed. However, there was a considerable incidence of ziconotide-associated AEs due to the rapid titration and high doses administered.
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Objectives. With respect to postoperative activities of daily living (ADL), we retrospectively investigated associated psychiatric symptoms that influenced beneficial effects of subthalamic nucleus (STN) stimulation in our Japanese patients with Parkinson disease (PD). Materials and Methods. Twenty-five patients underwent bilateral STN stimulation. Pre- and 3 months after the surgery, their parkinsonian symptoms were evaluated with Unified Parkinson Disease Rating Scale (UPDRS) and Schwab-England (S-E) ADL scale. ⋯ Preoperative score for intellectual impairment was only a significant predictor of worse postoperative ADL in "off" state. Conclusions. The markedly lower dose of levodopa may suggest ethnic characteristics of our Japanese patients with respect to tolerance for antiparkinsonian medications. Preoperative manifestation of drug-induced psychosis and cognitive dysfunction were the major factor that strikingly suppressed daily activities after STN stimulation.
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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.
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A rare complication of intrathecal drug therapy-inadvertent insertion of the intrathecal catheter into the matter of the spinal cord-is presented. The patient developed signs of progressive monoparesis immediately after implantation of an intrathecal drug delivery system. ⋯ The article discusses probable mechanism of the complication and possible ways of its prevention. The usefulness of CT myelography in determining the intrathecal catheter position relative to the spinal cord is emphasized.
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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.