Treatment Of Post-stroke Pain Research Articles

The mechanism and effect of repetitive transcranial magnetic stimulation for post-stroke pain.

Post-stroke pain (PSP) is a common complication after stroke and affects patients' quality of life. Currently, drug therapy and non-invasive brain stimulation are common treatments for PSP. Given the poor efficacy of drug therapy and various side effects, non-invasive brain stimulation, such as repetitive transcranial magnetic stimulation (rTMS), has been accepted by many patients and attracted the attention of many researchers because of its non-invasive and painless nature. This article reviews the therapeutic effect of rTMS on PSP and discusses the possible mechanisms. In general, rTMS has a good therapeutic effect on PSP. Possible mechanisms of its analgesia include altering cortical excitability and synaptic plasticity, modulating the release of related neurotransmitters, and affecting the structural and functional connectivity of brain regions involved in pain processing and modulation. At present, studies on the mechanism of rTMS in the treatment of PSP are lacking, so we hope this review can provide a theoretical basis for future mechanism studies.

Updates in the Treatment of Post-Stroke Pain.

To provide an overview of the current treatment strategies for common subtypes of post-stroke pain. There is growing research interest in non-pharmacological treatment approaches for chronic pain, including neurostimulation as well as lifestyle and psychosocial interventions. Newer pharmacotherapy research includes cannabinoids and NMDA-receptor antagonists as well as bee venom. Persistent post-stroke headache is an increasingly appreciated entity, though the role of novel chronic migraine treatments for post-stroke headache is not known. Overall, most treatment approaches to post-stroke pain lack high-quality evidence. Stroke survivors are in need of effective treatments based on methodologically sound evidence. To address the interplay of clinical and psychosocial factors that contribute to post-stroke pain, it may be reasonable to adopt a multimodal treatment strategy incorporating both lifestyle interventions and conventional therapies.

Importance of Pharmacological Evaluation in the Treatment of Poststroke Pain by Spinal Cord Stimulation

Spinal cord stimulation (SCS) is not typically recommended for the treatment of central poststroke pain (CPSP). We examined whether the pharmacological evaluation of CPSP is useful for selecting the candidates for SCS. Changes in visual analog scale (VAS) scores for pain following pharmacological evaluation using morphine, thiopental, and ketamine were compared with those following SCS in 22 CPSP patients. Twelve of the 22 (54.5%) patients in the ketamine test and thiopental test, and 5 (22.7%) of the 22 patients in the morphine test showed a more than 40% reduction in VAS score and were judged as "sensitive." Pain relief by SCS was estimated as excellent (≧60% VAS score reduction) in three patients, good (30-59% reduction) in nine patients, and fair (10-29% reduction) in seven patients 24 months after the start of SCS. The remaining 3 patients evaluated as having poor pain relief (<10% reduction) only underwent test SCS. VAS score reduction induced by SCS was more significant in ketamine-sensitive patients than in ketamine-resistant patients during the test SCS (p < 0.01, Mann-Whitney's U test) and 24 months after the start of chronic SCS (p < 0.05). However, there were no significant differences in results for thiopental-sensitive/thiopental-resistant or morphine-sensitive/morphine-resistant patients during the test SCS and 24 months after chronic SCS. Analysis of the rate of VAS score reduction by pharmacological evaluation and SCS showed significant correlations with the results of the ketamine test (r = 0.670, p = 0.001, Pearson's correlation coefficient test), but not with those of the thiopental (r = 0.291, p = 0.231) or morphine test (r = 0.327, p = 0.175). We speculate that the pharmacological evaluation of CPSP patients can be a useful tool for selecting candidates for SCS.

Treatment of Poststroke Pain by Epidural Motor Cortex Stimulation With a New Octopolar Lead

Chronic, drug-resistant neuropathic pain can be treated by surgically implanted motor cortex stimulation (MCS). The leads used for MCS have not been specifically designed for this application. To study the value of a new 8-contact lead for MCS therapy in a series of 6 patients with refractory central poststroke pain. The study comprised a 1-month randomized phase, starting 1 month after implantation, during which the neurostimulator was switched on in one-half of the patients or remained off in the other half, followed by an open phase of 10 months, during which the stimulator was switched on in all patients. Clinical assessment was performed at baseline and 1, 2, 3, 6, and 12 months after implantation with the following scales: Visual Analog Scale, Verbal Rating Scale, Brief Pain Inventory, McGill Pain Questionnaire, Sickness Impact Profile, and Medication Quantification Scale. In the randomized phase, clinical scores were found to be globally reduced in the on- vs off-stimulation condition. In the open follow-up phase, all clinical scores improved significantly over time. The ratio between affective and sensory McGill Pain Questionnaire subscores decreased, suggesting a preferential effect of MCS on the affective component of pain. Compared with preoperative baseline, 2 patients were totally relieved of central poststroke pain, 3 patients were very much relieved, and 1 patient remained unchanged at the final examination. A good clinical outcome was observed in all patients except 1, suggesting that this new octopolar lead could be used for MCS therapy to treat refractory central poststroke pain.

Recording of Corticospinal Evoked Potential for Optimum Placement of Motor Cortex Stimulation Electrodes in the Treatment of Post-stroke Pain -Two Case Reports-

The corticospinal motor evoked potential (MEP) evoked by motor cortex stimulation was investigated as an intraoperative index for the placement of stimulation electrodes in the epidural space over the motor cortex for the treatment of post-stroke pain. A grid of plate electrodes was placed in the epidural space to cover the motor cortex, sensory cortex, and premotor cortex employing a magnetic resonance imaging-guided neuronavigation system in two patients with severe post-stroke pain in the right extremities, a 66-year-old man with dysesthesia manifesting as burning and aching sensation, and a 67-year-old woman with dysesthesia manifesting as pricking sensation. The D-wave of the corticospinal MEP was recorded with a flexible wire electrode placed in the epidural space of the spinal cord during anodal monopolar stimulation of each plate electrode under general anesthesia. The grid electrode was fixed in position with dural sutures and the craniotomy closed. The effect of pain reduction induced by anodal monopolar stimulation of the same plate electrodes was examined using the visual analogue scale (VAS) on a separate day in the awake state without anesthesia. Comparison of the percentage VAS reduction and the recorded amplitude of the D-wave employing the same stimulation electrode revealed significant correlations in Case 1 (r = 0.828, p < 0.01) and Case 2 (r = 0.807, p < 0.01). The grid electrode was then replaced with two RESUME electrodes over the hand and foot areas, and the optimum positions were identified by D-wave recording before electrode fixation. Both patients reported satisfactory pain alleviation with lower stimulation voltages than usually required for patients with similar symptoms. These results indicate the potential of D-wave recording as an intraoperative indicator for the placement of stimulating electrodes over the motor cortex for pain relief.

中枢性とう痛に対する電気刺激療法

Central pain due to stroke, spinal cord injury and surgical or traumatic brain injury is frequently refractory, and therefore, electrical stimulation therapy including stimulation of the spinal cord, thalamus and cerebral cortex is indicated. In this report, we discuss a strategy for dealing with central pain. Spinal cord stimulation has been thought to be ineffective as a treatment for central pain. However, it is a less invasive therapy and is sometimes effective even on the post-stroke pain of extremities. On the other hand, cerebral cortex stimulation has recently been more popular as a treatment for post-stroke pain, and successful cases of treatment have also been documented following spinal cord injury. At the present time, it is difficult to conclude whether cerebral cortex or thalamic stimulation is more effective in the treatment of spinal cord pain. We discuss our strategy for central pain. Medication and observation for at least one year is needed before surgical therapy is considered. If medication is not effective, spinal cord stimulation should be considered. Next, cerebral cortex stimulation is recommended, and depending on the patient's condition, thalamic stimulation may also be indicated.