Azuma Hirayama

Reduction of intractable deafferentation pain by navigation-guided repetitive transcranial magnetic stimulation of the primary motor cortex

Abstract The precentral gyrus (M1) is a representative target for electrical stimulation therapy of pain. To date, few researchers have investigated whether pain relief is possible by stimulation of cortical areas other than M1. According to recent reports, repetitive transcranial magnetic stimulation (rTMS) can provide an effect similar to that of electrical stimulation. With this in mind, we therefore examined several cortical areas as stimulation targets using a navigation‐guided rTMS and compared the effects of the different targets on pain. Twenty patients with intractable deafferentation pain received rTMS of M1, the postcentral gyrus (S1), premotor area (preM), and supplementary motor area (SMA). Each target was stimulated with ten trains of 10‐s 5‐Hz TMS pulses, with 50‐s intervals in between trains. Intensities were adjusted to 90% of resting motor thresholds. Thus, a total of 500 stimuli were applied. Sham stimulations were undertaken at random. The effect of rTMS on pain was rated by patients using a visual analogue scale (VAS) and the short form of the McGill Pain Questionnaire (SF‐MPQ). Ten of the 20 patients (50%) indicated that stimulation of M1, but not other areas, provided significant and beneficial pain relief (p < 0.01). Results indicated a statistically significant effect lasting for 3 hours after the stimulation of M1 (p < 0.05). Stimulation of other targets was not effective. The M1 was the sole target for treating intractable pain with rTMS, in spite of the fact that M1, S1, preM, and SMA are located adjacently.

Reduction of intractable deafferentation pain due to spinal cord or peripheral lesion by high-frequency repetitive transcranial magnetic stimulation of the primary motor cortex

OBJECT The authors previously reported that navigation-guided repetitive transcranial magnetic stimulation (rTMS) of the precentral gyrus relieves deafferentation pain. Stimulation parameters were 10 trains of 10-second 5-Hz TMS pulses at 50-second intervals. In the present study, they used various stimulation frequencies and compared efficacies between two types of lesions. METHODS Patients were divided into two groups: those with a cerebral lesion and those with a noncerebral lesion. The rTMS was applied to all the patients at frequencies of 1, 5, and 10 Hz and as a sham procedure in random order. The effect of rTMS on pain was rated by patients using a visual analog scale. RESULTS The rTMS at frequencies of 5 and 10 Hz, compared with sham stimulation, significantly reduced pain, and the pain reduction continued for 180 minutes. A stimulation frequency of 10 Hz may be more effective than 5 Hz, and at 1 Hz was ineffective. The effect of rTMS at frequencies of 5 and 10 Hz was greater in patients with a noncerebral lesion than those with a cerebral lesion. CONCLUSIONS High-frequency (5- or 10-Hz) rTMS of the precentral gyrus can reduce intractable deafferentation pain, but low-frequency stimulation (at 1 Hz) cannot. Patients with a noncerebral lesion are more suitable candidates for high-frequency rTMS of the precentral gyrus.

Stimulation of primary motor cortex for intractable deafferentation pain

To treat intractable deafferentation pains, we prefer stimulation of the primary motor cortex (M1). The methods of stimulation we utilize are electrical stimulation and repetitive transcranial magnetic stimulation (rTMS). In our department, we first attempt rTMS, and if this rTMS is effective, we recommend the patient to undergo procedures for motor cortex stimulation (MCS). A 90% intensity of resting motor threshold setting is used for rTMS treatment. In this study ten trains of 5 Hz rTMS for 10 seconds (50 seconds resting interval) were applied to the M1, S1, pre-motor and supplementary motor areas. Only M1 stimulation was effective for pain reduction in 10 of 20 patients (50%). Twenty-nine MCS procedures were performed by subdural implantation of electrodes, and in the case of hand or face pain, electrodes were implanted within the central sulcus (11 cases), because the main part of M1 is located in the central sulcus in humans. The success rate of MCS was around 63%, and seemed to be higher in cases of pain with spinal cord and peripheral origins, while it was lower in cases of post-stroke pain.

Radiofrequency thermal ablation for recurrent meningioma extending extracranially

SummaryBackground. Image-guided and temperature-controlled radiofrequency thermal ablation techniques were applied to reduce tumor volume and relieve the symptoms caused by extracranial extension of recurrent meningioma.Method. We treated two patients with recurrent meningioma, an 81-year-old woman presenting with bulging of the temple and a 68-year-old woman presenting with visual disturbance, facial disfigurement, and sensory disturbance. Neuroimaging in both patients, revealed a large tumor extending extracranially and involving the infratemporal fossa. To avoid injury to important anatomical structures either compressed or entrapped by the tumor, the spatial relation between the planned ablation volume and these structures was confirmed by 3-D reconstruction of the ablation target. During the ablation procedure, local temperatures over the tissue being cauterized were continuously monitored to limit the ablation area to that within the planned volume adjusting RF power.Finding. Radiofrequency ablation produced tumor necrosis as planned without adverse effects and resulted in swift relief of symptoms and signs with shrinkage of the tumor.Conclusion. This technique may be an effective alternative for recurrent meningiomas extending extracranially and for which radical surgical procedures are not indicated.

FC2.1 Reduction of intractable deafferentation pain by navigation-guided repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex

Background: The precentral gyrus (M1) is a representative target for electrical stimulation therapy of intractable deafferentation pain. To date, few researchers have investigated whether pain relief is possible by stimulation of cortical areas other than M1. According to recent reports, rTMS can provide an effect similar to that of electrical stimulation. Objectives: We therefore examined several cortical areas as stimulation targets using a navigation-guided rTMS and we compared the effects of the different targets and stimulation frequencies on pain. Patients and methods: Twenty patients with intractable deafferentation pain received rTMS of M1, the postcentral gyrus (S1), premotor area (preM), and supplementary motor area (SMA). Each target was stimulated with ten trains of 10-s 5-Hz TMS pulses, with 50-s intervals in between trains. Intensities were adjusted to 90% of resting motor thresholds. Thus, a total 500 stimuli were applied. Sham stimulations were undertaken at random. In 13 patients, the stimulation frequencies were changed among 1, 5, 10 Hz and sham. The effect of rTMS on pain was rated by patients using a visual analogue scale (VAS) and the short form of the McGill Pain Questionnaire (SF-MPQ). Results: Ten of the 20 patients (50%) indicated that stimulation of M1, but not other areas, provided significant and beneficial pain relief (p < 0.01). Results indicated a statistically significant effect lasting for 3 h after the stimulation of M1 (p < 0.05). The stimulations with the frequencies of 5 and 10 Hz were significantly effective on the pain reduction but 1 Hz was not in VAS against the sham. Conclusions: The M1 was the sole target for treating intractable pain with rTMS, in spite of the fact that M1, S1, preM and SMA are located adjacently. Probably high frequency rTMS of M1 is needed to induce the activation of several brain areas to reduce the intractable pain, and low frequency is not enough.