Articles: chronic-pain.
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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. 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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Assessment and management of pain for nursing home residents is frequently reported to be inadequate, yet few studies have used objective criteria to measure the quality of care related to pain. ⋯ Infrequent or incomplete physician pain assessment and treatment and inaccurate documentation by licensed nurses limits evaluation of pain care quality based on medical record review alone. A brief resident interview identified participants reporting symptoms of chronic pain not documented in the medical record and those with a preference for medication. Initial targeting of residents with self-reported pain maximizes the efficiency of the standardized scoring system described in this study. Focusing on explicit process measures clearly identifies areas for improvement and represents an important step in assessing the quality of pain care in the NH.
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Ziconotide is an N-type calcium channel (NCC) blocking conopeptide, acting primarily at the NCC-rich dorsal horn. Reported here is an early experience with intrathecal ziconotide in a 55-year-old man with chronic pain resulting from failed back surgery. ⋯ The dosing regimen, onset and resolution of adverse events, and improvement on the primary efficacy measure, the Visual Analog Scale of Pain Intensity, are discussed. Overall, the patient responded positively to ziconotide.