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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although electrical stimulation of the precentral gyrus (MCS) is emerging as a promising technique for pain control, its mechanisms of action remain obscure, and its application largely empirical. Using positron emission tomography (PET) we studied regional changes in cerebral flood flow (rCBF) in 10 patients undergoing motor cortex stimulation for pain control, seven of whom also underwent somatosensory evoked potentials and nociceptive spinal reflex recordings. The most significant MCS-related increase in rCBF concerned the ventral-lateral thalamus, probably reflecting cortico-thalamic connections from motor areas. CBF increases were also observed in medial thalamus, anterior cingulate/orbitofrontal cortex, anterior insula and upper brainstem; conversely, no significant CBF changes appeared in motor areas beneath the stimulating electrode. Somatosensory evoked potentials from SI remained stable during MCS, and no rCBF changes were observed in somatosensory cortex during the procedure. Our results suggest that descending axons, rather than apical dendrites, are primarily activated by MCS, and highlight the thalamus as the key structure mediating functional MCS effects. A model of MCS action is proposed, whereby activation of thalamic nuclei directly connected with motor and premotor cortices would entail a cascade of synaptic events in pain-related structures receiving afferents from these nuclei, including the medial thalamus, anterior cingulate and upper brainstem. MCS could influence the affective-emotional component of chronic pain by way of cingulate/orbitofrontal activation, and lead to descending inhibition of pain impulses by activation of the brainstem, also suggested by attenuation of spinal flexion reflexes. In contrast, the hypothesis of somatosensory cortex activation by MCS could not be confirmed by our results.
Pain 1999 Nov
PMID:Electrical stimulation of motor cortex for pain control: a combined PET-scan and electrophysiological study. 1053 98

Electrical stimulation of the motor cortex (MCS) is a promising and increasingly used neurosurgical technique for the control of refractory neuropathic pain. Although its mechanisms of action remain unknown, recent functional imaging data suggest involvement of the thalamus, brainstem and anterior cingulate/orbitofrontal cortex. Since some of these areas are also implicated in higher cognitive functions, notably attentional processes, we analysed cognitive ERPs and behavioural performance during an "oddball" auditory detection task in patients submitted to this procedure. Eleven consecutive patients undergoing MCS because of neuropathic refractory pain, ranging in age from 25 to 71 years, were included in the study. ERPs were obtained in all cases both during the application ("MCS-on") and within the 10 min that followed discontinuation of the procedure ("MCS-off"). In five patients, ERPs could also be obtained just before the start of MCS. When the patients' sample was taken as a whole, there were no consistent effects of MCS on the ERPs. There was, however, a significant interaction of MCS action with the patients' age, reflecting a significant delay during MCS of the cognitive responses N2 and P3 (N200 and P300) in the group of patients older than 50 years exclusively. This effect was rapidly reversible after MCS discontinuation. No MCS-related changes were observed in the N1 component. At the individual level, the effect of MCS on the endogenous ERPs was highly variable, ranging from a total stability of ERPs (mostly in younger subjects) to latency differences of tens of milliseconds in the older group. These results, together with recent experiments showing P300 alteration during repetitive transcranial stimulation, suggest that motor cortex stimulation may interfere with relatively simple cognitive processes such as those underlying target detection, and that the risk of abnormal cognitive effects related to cortical stimulation may increase with age. Although the procedure appears on the whole remarkably safe, complementary neuropsychological studies in this category of patients are advised, as well as caution to possible adverse cognitive effects when using MCS in the elderly, notably in the presence of pre-existent cerebral lesions.
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PMID:Cognitive effects of precentral cortical stimulation for pain control: an ERP study. 1249 Mar 29

Facial neuralgia is the last common pathway for a variety of pathological conditions with different etiology. Neuropathic facial pain is often refractory to routine medical or surgical treatments. We present here a long-term follow-up of two patients with unilateral facial neuropathic pain due to idiopathic trigeminal neuropathy or to surgical trauma to the glossopharyngeal nerve, respectively. These patients have been treated by other modalities for several years without obtaining satisfactory pain relief. Electrical stimulation of the motor cortex (MCS) with a quadripolar electrode contralateral to the painful area of the face was attempted in both cases for control of the facial pain, and resulted in immediate analgesia with more than 50% pain reduction. During a follow-up period of 72 months, a sufficient (> 50%) and stable analgesic effect of MCS was observed. These cases are discussed and the recent literature on MCS is reviewed in an attempt to identify indications for MCS as well as key structures in the brain for mediating the MCS effect.
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PMID:Motor cortex stimulation for neuropathic facial pain. 1263 15

In this study, 107 primary total joint replacement (TJR) patients were assessed preoperatively using the SF-36 (Mental Component Score [MCS] and Physical Component Score [PCS]), Beck Depression Inventory (BDI), Spielberger Trait Anxiety Inventory, Interpersonal Support Evaluation List, and the Coping Strategies Questionnaire. Patients with preoperative MCS < 50 had significantly higher trait anxiety (P <.001), higher BDI scores (P <.001), and lower appraisal (P <.018) and belonging (P <.006) support when compared with patients with preoperative MCS > or = 50. Low MCS patients used more catastrophizing coping techniques (P <.001) and reported poorer pain control (P <.04). A multivariate prediction model found that adding preoperative MCS to baseline demographic and physical function (PCS) measures significantly improved the prediction of 6-month change in PCS. Further research should evaluate the role of multimodality emotional support in assuring optimal physical return after TJR.
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PMID:Psychological attributes of preoperative total joint replacement patients: implications for optimal physical outcome. 1545 31

The Swiss Organ Living Donor Health Registry (SOL-DHR) started in April 1993. The purpose was the prospective and sequential follow up of donors long-term health. Between 1993 and January 2005 737 Living Kidney donations were registered and followed. Two thirds of donors were female and two thirds of recipients male. The three most common relations were life-partners, parents and siblings (approximately 30% each). 10% of donors could not be followed since living far abroad and 5% were lost due to missing current address after moving. 9 donors died (4 malignancies, 2 traffic accidents, 1 myocardial infarction, 1 stroke and 1 suicide), non due to kidney donation. Perioperative complications were age dependent, ranging from 17% in donors below the age of 40 year and 46% in donors older than 70 years. The longterm complications were divided in surgical, medical and psychological ones. The most common surgical long-term complications were pain (cicatrice, back, abdomen) and hernias. The major medical complications were hypertension (35% at seven years after donation) and rising rate of Albuminuria (9% at seven years). Although hypertension was not higher than in an age matched Swiss control population, untreated hypertension was regarded as the higher risk for development of glomerulosclerosis than in people with two kidneys. No donor went into end stage renal failure. Using the SF-8-Test to quantify the psychological well-being the mean MCS (mental component summary) was 54.3 +/- 7.8 as compared to 52.9 +/- 7.7 in the age matched control population. MCS was low (< 40) in 6.2% and very low (< 25) in 2.2% of donors. 94.4 % of donors would donate again, while 4.3% would not (mostly women). The reasons not to donate again was mainly related to poor outcome of the kidney recipient, or long-lasting major pain or disappointment about medical handling before (not enough information, wrong advice) and after organ donation. The association of Swiss Living Organ Donors, where only kidney or liver donors can become a member, are organising self-help-groups for pain, psychological and financial problems (with health insurances). The organisation and financial support of SOL-DHR is briefly described. The waste majority of living kidney donors are very satisfied about the free care given by SOL-DHR.
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PMID:[The Swiss Organ Living Donor Health Registry (SOL-DHR)]. 1607 50

Thirty-one patients with medically refractory neuropathic pain were included in a prospective evaluation of motor cortex stimulation. The long-term outcome was evaluated using five variables: (a) rate (percentage) of pain relief, (b) pain scores as assessed on VAS, (c) postoperative decrease in VAS scores, (d) reduction in analgesic drug intake, (e) a dichotomic (yes/no) response to the question whether the patient would accept, under similar circumstances, to be operated on again. Pain relief was rated as excellent (>70 % pain relief) in 10 % of cases, good (40-69 %) in 42 %, poor (10-39 %) in 35 % and negligible (0-9 %) in 13 %. Intake of analgesic drugs was decreased in 52 % of patients and unchanged in 45 % (unavailable data in 3 %), with complete withdrawal of analgesic drugs in 36 % of patients. Twenty-one patients (70 %) declared themselves favourable to re-intervention if the same beneficial outcome could be guaranteed. Neither preoperative motor status, pain characteristics, type or localisation of lesions, quantitative sensory testing, Somatosensory Evoked Potentials, nor the interval between pain and surgery were found to predict the efficacy of MCS. The level of pain relief, as evaluated in the first month following implantation was a strong predictor of long-term relief (regression analysis, R=0.744; p<0.0001). These results confirm that MCS can be a satisfactory and durable alternative to medical treatments in patients with refractory pain, and suggest that the efficacy of MCS may be predicted in the first month of therapy.
Pain 2005 Nov
PMID:Motor cortex stimulation for refractory neuropathic pain: four year outcome and predictors of efficacy. 1620 35

A randomized, double-blind, placebo-controlled study of low-level laser therapy (LLLT) in 90 subjects with chronic neck pain was conducted with the aim of determining the efficacy of 300 mW, 830 nm laser in the management of chronic neck pain. Subjects were randomized to receive a course of 14 treatments over 7 weeks with either active or sham laser to tender areas in the neck. The primary outcome measure was change in a 10 cm Visual Analogue Scale (VAS) for pain. Secondary outcome measures included Short-Form 36 Quality-of-Life questionnaire (SF-36), Northwick Park Neck Pain Questionnaire (NPNQ), Neck Pain and Disability Scale (NPAD), the McGill Pain Questionnaire (MPQ) and Self-Assessed Improvement (SAI) in pain measured by VAS. Measurements were taken at baseline, at the end of 7 weeks' treatment and 12 weeks from baseline. The mean VAS pain scores improved by 2.7 in the treated group and worsened by 0.3 in the control group (difference 3.0, 95% CI 3.8-2.1). Significant improvements were seen in the active group compared to placebo for SF-36-Physical Score (SF36 PCS), NPNQ, NPAD, MPQVAS and SAI. The results of the SF-36 - Mental Score (SF36 MCS) and other MPQ component scores (afferent and sensory) did not differ significantly between the two groups. Low-level laser therapy (LLLT), at the parameters used in this study, was efficacious in providing pain relief for patients with chronic neck pain over a period of 3 months.
Pain 2006 Sep
PMID:The effect of 300 mW, 830 nm laser on chronic neck pain: a double-blind, randomized, placebo-controlled study. 1713 27

To investigate brain mechanisms whereby electrical stimulation of the motor cortex (MCS) may induce pain relief in patients with neuropathic pain, cerebral blood flow (CBF) changes were studied using H2O PET in 19 consecutive patients treated with MCS for refractory neuropathic pain. Patients were studied in three conditions, (a) before MCS (Baseline, stimulator stopped 4 weeks before), (b) during a 35-min period of MCS and (c) during a 75-min period after MCS had been discontinued (OFF). Compared to Baseline, turning on the stimulator was associated with CBF increase in the contralateral (anterior) midcingulate cortex (aMCC, BA24 and 32) and in the dorso-lateral prefrontal (BA10) cortices. The most important changes of CBF were observed in the 75 min after discontinuation of MCS (OFF). This post-stimulation period was associated with CBF increases in a large set of cortical and subcortical regions (from posterior MCC (pMCC) to pregenual (pg) ACC, orbitofrontal cortex, putamen, thalami, posterior cingulate and prefrontal areas) and in the brainstem (mesencephalon/periaqueductal grey (PAG) and pons). CBF changes in the post-stimulation period correlated with pain relief. Functional connectivity analysis showed significant correlation between pgACC and PAG, basal ganglia, and lower pons activities, supporting the activation of descending ACC-to-PAG connections. MCS may act in part through descending (top-down) inhibitory controls that involve prefrontal, orbitofrontal and ACC as well as basal ganglia, thalamus and brainstem. These hemodynamic changes are lengthened and might therefore underlie the long-lasting clinical effects that largely outlast the actual stimulation periods.
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PMID:Motor cortex stimulation in neuropathic pain. Correlations between analgesic effect and hemodynamic changes in the brain. A PET study. 1705 97

Chronic motor cortex stimulation is a treatment option for neuropathic drug-resistant pain and possibly associated movement disorders. Preliminary studies suggest the possibility to treat symptoms of Parkinson disease in selected patients. Recently, MCS has been suggested to enhance motor recovery in patients with poststroke hemiparesis. One or more electrodes are placed extradurally over the motor cortex through a burr hole or a small craniotomy, and then connected to a totally implantable neurostimulator. The accurate positioning of the stimulating electrodes over the motor cortex is the key point of the surgical procedure. Motor cortex identification results from the integration of anatomical, neuroradiological, functional, and neurophysiological data, taking into account the huge population variability. Intraoperative neurophysiological mapping of the motor cortex is of paramount importance, in spite of very sophisticated neuroradiological mathematical reconstructions of the motor area. We discuss and compare the different techniques that are utilized by different authors. Moreover, clinical neurophysiology is also helpful in evaluating the results of this neuromodulation procedure and in hypothesizing the mechanisms that are put in play by MCS.
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PMID:Neurophysiological aspects of chronic motor cortex stimulation. 1808

Since initial reports in the early 1990s, stimulation of the M1 region of the cortex (MCS) has been used to treat chronic refractory pain conditions and a variety of movement disorders. A Medline search of literature between 1991 and 2007 revealed 512 cases using MCS. Although most of these relate to the treatment of pain (422), 84 of them involve movement disorders. More recently, several studies have specifically looked at treating Parkinson's disease (PD) with MCS. We report here several of our own cases using MCS to treat poststroke and non-poststroke pain syndromes and movement disorders (n = 8), PD (n = 4), ET (n = 2), and cortico-basal degeneration (n = 1). We also cover the essential history of this procedure and our current research using computational modeling to understand further the underlying mechanisms of MCS.
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PMID:Motor cortex stimulation for pain and movement disorders. 1816 82


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