Articles: neuropathic-pain.
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Observational Study
The Franco-Canadian multicolumn spinal cord stimulation prospective study: a subgroup analysis focusing on the decisive role of lead positioning.
Multicolumn spinal cord stimulation (SCS) is now considered to be effective for the treatment of the radicular and back component in refractory Failed Back Surgery Syndrome (FBSS) patients. The relationship between the paresthesia coverage of the back and clinical outcomes has recently been confirmed by an international prospective study. However, significant disparities in outcomes were identified and could result from the heterogeneity of lead implantation parameters which are dependant on local practices and experience. We therefore sought to analyse the impact of lead implantation level and its lateralization on the ability to address back pain with multicolumn SCS leads. ⋯ Despite limitations in this retrospective subgroup analysis, this study suggests that the vertebral level (T8-T9) and midline positioning of the lead during implantation could be decisive factors to optimize paresthesia coverage and finally, clinical and functional outcomes. While sophistication has been responsible for an increase of the size and the programming possibilities of surgical SCS leads during the past years, multicolumn SCS lead implantation should in fact be considered as a "functional neurosurgical" procedure and could benefit from intraoperative patient cooperation, as in the case for deep brain stimulation procedures, due to minimally invasive implantation techniques.
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Expert Rev Neurother · Mar 2015
ReviewProgress in the treatment of small fiber peripheral neuropathy.
Small fiber neuropathy is a syndrome of diverse disease etiology because of multiple pathophysiologic mechanisms with major presentations of neuropathic pain and autonomic symptoms. Over the past decade, there has been substantial progress in the treatments for neuropathic pain, dysautonomia and disease-modifying strategy. In particular, anticonvulsants and antidepressants alleviate neuropathic pain based on randomized clinical trials.
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Human experimental pain models are widely used to study drug effects under controlled conditions, but they require further optimization to better reflect clinical pain conditions. To this end, we measured experimentally induced pain in 110 (46 men) healthy volunteers. The quantitative sensory testing (QST) battery (German Research Network on Neuropathic Pain) was applied on untreated ("control") and topical capsaicin-hypersensitized ("test") skin. ⋯ Inclusion in the respective clusters was predictable at a cross-validated accuracy of 86.9% by a classification and regression tree comprising 3 QST parameters (mechanical pain sensitivity, wind-up ratio, and z-transformed thermal sensory limen) from the control sites. Thus, we found that topical capsaicin partly induced the desired clinical pattern of neuropathic pain in a preselectable subgroup of healthy subjects to a degree that fuels expectations that experimental pain models can be optimized toward mimicking clinical pain. The subjects, therefore, qualify for enrollment in analgesic drug studies that use highly selected cohorts to enhance predictivity for clinical analgesia.
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Brain Behav. Immun. · Mar 2015
Stromal cell-derived CCL2 drives neuropathic pain states through myeloid cell infiltration in injured nerve.
Neuropathic pain resulting from peripheral nerve injury involves many persistent neuroinflammatory processes including inflammatory chemokines that control leukocyte trafficking and activate resident cells. Several studies have shown that CCL2 chemokine, a potent attractant of monocytes, and its cognate receptor, CCR2, play a critical role in regulating nociceptive processes during neuropathic pain. However, the role of CCL2 in peripheral leukocyte infiltration-associated neuropathic pain remains poorly understood. ⋯ Using a specific CCR2 antagonist and mice with a CCL2 genetic deletion, we have also established that the CCL2/CCR2 axis drives monocyte/macrophage infiltration and pain hypersensitivity in the CCI model. Finally, specific deletion of CCL2 in stromal or immune cells respectively using irradiated bone marrow-chimeric CCI mice demonstrated that stromal cell-derived CCL2 (in contrast to CCL2 immune cell-derived) tightly controls monocyte/macrophage recruitment into the lesion and plays a major role in the development of neuropathic pain. These findings demonstrate that in chronic pain states, CCL2 expressed by sciatic nerve cells predominantly drove local neuro-immune interactions and pain-related behavior through CCR2 signaling.
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Patients with chronic pain usually suffer from cognitive impairment, with memory deterioration being the most common deficit that affects daily functioning and quality of life. The causes for this impairment are not clear despite intensive clinical studies. Few studies have evaluated impaired learning using animal models of persistent pain. ⋯ The results of this study suggest that trigeminal neuralgia induced by cobra venom in adult rats can impair spatial learning and memory function over time and results in demonstrable changes in the ultrastructure of the medulla oblongata. This new animal model may be useful for future studies on the effect of chronic pain on learning and cognition.