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We have applied bipolar dual-lead spinal cord stimulation (SCS) between two cylinder-type electrodes placed on the ventral and dorsal sides of the spinal cord (dual-VD-SCS). A 36-year-old man suffered from burning pain from his right elbow down to his hand after brachial plexus avulsion. The areas with paresthesia induced by conventional SCS did not include the painful hand area. However, dual-VD-SCS completely induced paresthesia in the painful hand area. We speculate that dual-VD-SCS can be applied to stimulate deeper sites of the dorsal column and dorsal horn than conventional SCS and is useful for pain reduction.

Twenty-one vegetative state (VS) patients and 10 minimally conscious state (MCS) patients were treated by spinal cord stimulation (SCS) following an electrophysiological evaluation 3 months or more after the onset of brain injury.A flexible four-contact cylindrical electrode was inserted into the epidural space of the cervical vertebrae, and placed at cervical levels C2-C4. Five-hertz stimulation was applied for 5 min every 30 min during the daytime at an intensity that produced muscle twitches of the upper extremities.Both the fifth wave in the auditory brainstem response (ABR) and N20 in the somatosensory evoked potential (SEP) were detected in 8 of the 21 VS patients and 9 of the 10 MCS patients. Of the 3 VS patients and 7 MCS patients who recovered following SCS therapy, all showed a preserved fifth wave in the ABR and N20 in the SEP, and all had received SCS therapy within 9 months after the onset of brain injury. Although the 3 patients who recovered from VS remained in a bedridden state, all 7 patients who recovered from MCS were able to emerge from the bedridden state within 12 months after the start of SCS.Five-hertz cervical SCS caused increased cerebral blood flow (CBF) and induced muscle twitches of the upper extremities, and MCS patients showed a remarkable recovery of consciousness and motor function in the upper extremities compared with the lower extremities. This SCS method could be a new neuromodulation and neurorehabilitation technique, and MCS patients may be good candidates for SCS therapy.

Twenty-one vegetative state (VS) patients and 10 minimally conscious state (MCS) patients were treated by spinal cord stimulation (SCS) following an electrophysiological evaluation 3 months or more after the onset of brain injury.

Object Holmes' tremor (HT) is generally considered to be a symptomatic tremor associated with lesions of the cerebellum, midbrain, or thalamus. Deep brain stimulation (DBS) therapy for essential tremor and parkinsonian tremor has proved quite successful. In contrast, surgical treatment outcomes for HT have often been disappointing. The use of 2 ipsilateral DBS electrodes implanted in parallel within the thalamus for severe essential tremor has been reported. Since dual-lead stimulation within a single target can cover a wider area than single-lead stimulation, it produces greater effects. On the other hand, DBS of the subthalamic area (SA) was recently reported to be effective for refractory tremor. Methods The authors implanted 2 DBS electrodes (one at the nucleus ventralis oralis/nucleus ventralis intermedius and the other at the SA) in 4 patients with HT. For more than 2 years after implantation, each patient's tremor was evaluated using a tremor rating scale under the following 4 conditions of stimulation: “on” for both thalamus and SA DBS; “off” for both thalamus and SA DBS; “on” for thalamus and “off” for SA DBS; and “on” for SA and “off” for thalamus DBS. Results The tremor in all patients was improved for more than 2 years (mean 25.8 ± 3.5 months). Stimulation with 2 electrodes exerted greater effect on the tremor than did 1-electrode stimulation. Interestingly, in all patients progressive effects were observed, and in one patient treated with DBS for 1 year, tremor did not appear even while stimulation was temporarily switched off, suggesting irreversible improvement effects. The presence of both resting and intentional/action tremor implies combined destruction of the pallidothalamic and cerebellothalamic pathways in HT. A larger stimulation area may thus be required for HT patients. Multitarget, dual-lead stimulation permits coverage of the wide area needed to suppress the tremor without adverse effects of stimulation. Some reorganization of the neural network may be involved in the development of HT because the tremor appears several months after the primary insult. The mechanism underlying the absence of tremor while stimulation was temporarily off remains unclear, but the DBS may have normalized the abnormal neural network. Conclusions The authors successfully treated patients with severe HT by using dual-electrode DBS over a long period. Such DBS may offer an effective and safe treatment modality for intractable HT.

Objectives Intention tremor becomes evident only when patients intend to move their body and is characterized by dysmetria. We have developed an on-demand control system that triggers the switching on/off of deep brain stimulation (DBS) instantly for the control of intention tremor. Material and Methods We used surface electrodes for the recording of electromyographic (EMG) activity, and the power of EMG activity was analyzed instantly employing the fast Fourier transform. The on-demand control system switched on DBS when only the power of tremor frequency exceeded the on-trigger threshold, and the system switched off DBS when the total power of EMG activity decreased below the off-trigger threshold. Results The on-demand control system triggered the switching on/off of DBS accurately, and controlled intention tremor completely. Our on-demand control system is small and portable, and suitable for clinical use. Conclusions The on-demand control system for DBS is useful for controlling intention tremor and may decrease the incidence of tolerance to DBS and may be a powerful tool for various applications of neuromodulation therapy.

Objective High-intensity and high-frequency repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex was carried out in poststroke patients with increased spasticity, and the changes in F-wave parameters in comparison with M-wave parameters induced by rTMS were examined. Methods Ten-hertz rTMS pulses were delivered to the primary motor cortex of the lesion side at 110% intensity of the resting motor threshold, and F-waves were obtained from the first dorsal interosseous muscle. F-waves were recorded before (pre-stim) and immediately after the end of rTMS (post-stim) in poststroke patients. Results F-wave persistence and F/M Amp.Ratio increased significantly in patients with lesions in upper motor tract as compared with healthy subjects (Wilcoxon rank sum test, p = 0.00023 and p = 0.0073, respectively). After the rTMS application, both F-wave persistence and F/M Amp.Ratio decreased significantly (paired t-test, p = 0.0095 and p = 0.037, respectively). However, the F-wave amplitude did not show a statistically significant variance in poststroke patients. Conclusions High-frequency suprathreshold rTMS may suppress the F-waves by enhancing the inhibitory effect on spinal excitability through the corticospinal tract, and F-wave persistence and F/M Amp.Ratio can be used to determine the effect of rTMS on patients with increased spasticity.

Minimally conscious state (MCS) is characterized by inconsistent but clearly discernible behavioral evidence of consciousness, and can be distinguished from coma and the vegetative state (VS). Ten MCS patients were evaluated neurologically and electrophysiologically over 3 months after the onset of brain injury, and were treated by spinal cord stimulation (SCS). A flexible four-contact, cylinder electrode was inserted into the epidural space of the cervical vertebrae, and placed at the C2-C4 levels. Stimulation was applied for 5 minutes every 30 minutes during the daytime at an intensity that produced motor twitches of the upper extremities. We used 5 Hz for SCS, considering that the induced muscle twitches can be a useful functional neurorehabilitation for MCS patients. Eight of the 10 MCS patients satisfied the electrophysiological inclusion criteria, which we proposed on the basis of the results of deep brain stimulation for the treatment of patients in the VS. Seven patients recovered from MCS following SCS therapy, and were able to carry out functional interactive communication and/or demonstrate the functional use of two different objects. Cervical SCS increased cerebral blood flow (CBF) diffusely in the brain, and CBF increased by 22.2% during the stimulation period compared with CBF before stimulation in MCS patients (p < 0.0001, paired t-test). Five-Hz cervical SCS could increase CBF and induce muscle twitches of the upper extremities. This SCS therapy method may be suitable for treating MCS.

Objective: The development of image-guided systems rendered it possible to perform frameless stereotactic surgery for deep brain stimulation (DBS). As well as stereotactic targeting, neurophysiological identification of the target is important. Multitract microrecording is an effective technique to identify the best placement of an electrode. This is a report of our experience of using the Nexframe frameless stereotaxy with Ben’s Gun multitract microrecording drive and our study of the accuracy, usefulness and disadvantages of the system. Methods: Five patients scheduled to undergo bilateral subthalamic nucleus (STN) DBS were examined. The Nexframe device was adjusted to the planned target, and electrodes were introduced using a microdrive for multitract microrecording. In addition to the Nexframe frameless system, we adopted the Leksell G frame to the same patients simultaneously to use a stereotactic X-ray system. This system consisted of a movable X-ray camera with a crossbar and was adopted to be always parallel to the frame with the X-ray film cassette. The distance between the expected and actual DBS electrode placements was measured on such a stereotactic X-ray system. In addition, the distance measured with this system was compared with that measured by conventional frame-based stereotaxy in 20 patients (40 sides). Results: The mean deviations from 10 planned targets were 1.3 ± 0.3 mm in the mediolateral (x) direction, 1.0 ± 0.9 mm in the anteroposterior (y) direction and 0.5 ± 0.6 mm in the superoposterior (z) direction. The data from the frame-based stereotaxy in our institute were 1.5 ± 0.9 mm in the mediolateral (x) direction, 1.1 ± 0.7 mm in the anteroposterior (y) direction and 0.8 ± 0.6 mm in the superoposterior (z) direction. Then, differences were not statistically significant in any direction (p > 0.05). The multitract microrecording procedure associated with the Nexframe was performed without any problems in all of the patients. None of these electrodes migrated during and/or after the surgery. However, the disadvantage of the system is the narrow surgical field for multiple electrode insertion. Coagulating the cortex and inserting multiple electrodes under such a narrow visual field were complicated. Conclusion: The Nexframe with multitract microrecording for STN DBS still has some problems that need to be resolved. Thus far, we do not consider that this technology in its present state can replace conventional frame-based stereotactic surgery. The accuracy of the system is similar to that of frame-based stereotaxy. However, the narrow surgical field is a disadvantage for multiple electrode insertion. Improvement on this point will enhance the usefulness of the system.

For the treatment of intractable neuropathic pain, drug challenge test is necessary and useful to examine the pharmacological background of the pain in each case. Based on the results of drug challenge test, we can select the candidates for low-dose ketamine drip infusion (LDKDI) therapy and cerebrospinal stimulation therapy. In cerebrospinal stimulation therapy, dual-lead spinal cord stimulation should be selected at first, since we can insert electrodes percutaneously and this is suitable for both the test stimulation and chronic implantation. For the treatment of peripheral deafferentation pain, which includes phantom limb pain and peripheral nerve injury pain, deep brain stimulation therapy of the thalamic relay nucleus is suitable. Motor cortex stimulation therapy is suitable for the treatment of central deafferentation pain, which includes post-stroke pain. LDKDI therapy combined with cerebrospinal stimulation therapy achieves remarkable pain reduction in the treatment of neuropathic pain.

Introduction. Chronic thalamic stimulation has been confirmed as an effective treatment for tremor. The optimal target has been commonly accepted to be situated within the ventral thalamus, but a standard trajectory of the deep brain stimulation (DBS) electrode has not yet been established. Materials and Methods. A 53-year-old man with an 11-year history of essential tremor was treated by DBS of the thalamus. In this patient, we had a chance to compare the effects of different trajectory angles of the DBS electrode on tremor. Results. Intraoperative stimulation with the DBS electrode temporarily inserted at a high angle to the horizontal plane of the anterior commissure-posterior commissure (AC-PC) line to cover only the nucleus ventralis intermedius (Vim) was not effective. In contrast, stimulation with the DBS electrode permanently implanted at a low angle, covering a wide area extending from the nucleus ventralis oralis (Vo) to the Vim, reduced the tremor. Conclusion. We report on the case of a patient who showed different effects on tremor depending on the trajectory angle of the DBS electrode to the AC-PC line. The insertion trajectory of the DBS electrode may be an important factor for the treatment of tremor.

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.

Objectives 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. Materials and Methods 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. Results 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 (

Deep brain stimulation (DBS) is a surgical procedure used to treat various neurological disorders such as intractable pain, Parkinson’s disease, essential tremor, dystonia, and other movement disorders. It involves implanting electrodes in the brain, which send electrical impulses to modulate brain activity. This procedure is not considered radical and can significantly improve disabling neurological symptoms. Such symptoms used to commonly require invasive surgeries such as thalamotomy and pallidotomy, which destroy those parts of the brain where abnormal activity has occurred. In recent years, such surgeries have been performed less frequently because of the risk of severe complications and the availability of DBS, which is safer and has fewer complications. Deep brain stimulation allows abnormal brain activity to be regulated without destruction of brain tissue. This means that DBS offers numerous advantages over conventional surgeries as it is reversible and enables the surgeon to modulate and improve specific functions or symptoms. Despite DBS having become widely accepted as an effective therapy for various neurological disorders, its fundamental principles and mechanisms are still not precisely defined.

Holmes' tremor (HT) is generally considered to be a symptomatic tremor associated with lesions of the cerebellum, midbrain, or thalamus. Deep brain stimulation (DBS) therapy for essential tremor and parkinsonian tremor has proved quite successful. In contrast, surgical treatment outcomes for HT have often been disappointing. The use of 2 ipsilateral DBS electrodes implanted in parallel within the thalamus for severe essential tremor has been reported. Since dual-lead stimulation within a single target can cover a wider area than single-lead stimulation, it produces greater effects. On the other hand, DBS of the subthalamic area (SA) was recently reported to be effective for refractory tremor.The authors implanted 2 DBS electrodes (one at the nucleus ventralis oralis/nucleus ventralis intermedius and the other at the SA) in 4 patients with HT. For more than 2 years after implantation, each patient's tremor was evaluated using a tremor rating scale under the following 4 conditions of stimulation: "on" for both thalamus and SA DBS; "off" for both thalamus and SA DBS; "on" for thalamus and "off" for SA DBS; and "on" for SA and "off" for thalamus DBS.The tremor in all patients was improved for more than 2 years (mean 25.8 ± 3.5 months). Stimulation with 2 electrodes exerted greater effect on the tremor than did 1-electrode stimulation. Interestingly, in all patients progressive effects were observed, and in one patient treated with DBS for 1 year, tremor did not appear even while stimulation was temporarily switched off, suggesting irreversible improvement effects. The presence of both resting and intentional/action tremor implies combined destruction of the pallidothalamic and cerebellothalamic pathways in HT. A larger stimulation area may thus be required for HT patients. Multitarget, dual-lead stimulation permits coverage of the wide area needed to suppress the tremor without adverse effects of stimulation. Some reorganization of the neural network may be involved in the development of HT because the tremor appears several months after the primary insult. The mechanism underlying the absence of tremor while stimulation was temporarily off remains unclear, but the DBS may have normalized the abnormal neural network.The authors successfully treated patients with severe HT by using dual-electrode DBS over a long period. Such DBS may offer an effective and safe treatment modality for intractable HT.

Background and Objective: Deep brain stimulation (DBS) candidates with neurologic diseases such as unruptured aneurysm present additional challenges to neurosurgeons when craniotomy must precede DBS surgery. Such craniotomy may potentially overlap with intended burr hole sites for the later insertion of DBS electrodes, and the skin incision for craniotomy may lie very close to or intersect with that for the burr holes. We report here a case of forehead craniotomy prior to DBS surgery in which we employed a neuronavigation system to simulate locations for the craniotomy and burr holes. Method: A 62-year-old male patient with Parkinson's disease was a candidate for DBS. He also had an aneurysm and was planned first to undergo frontal craniotomy for clipping before the DBS surgery. The locations of the craniotomy, burr holes, and skin incisions were therefore simulated using a neuronavigation system during craniotomy. Results: Two weeks after the craniotomy, the patient underwent DBS surgery. Planning software confirmed the absence of cortical veins beneath the entry points of tentative burr holes and aided trajectory planning. The DBS surgery was performed without the interference of the burr holes and head pins and the craniotomy. Conclusion: Simulation of the locations of craniotomy and burr holes using a neuronavigation system proved valuable in the present case of frontal craniotomy before DBS surgery.

Objectives Intracranial hemorrhage is a crucial complication of deep brain stimulation (DBS) surgery. The bleeding caused by mechanical tissue injury due to microelectrode and/or DBS electrode lead insertion has been well studied. However, hemorrhage caused by a congenital underlying disease such as vascular malformation has not been examined carefully. Materials and Methods We encountered a case of intracerebral hemorrhage from arteriovenous malformation (AVM) after DBS surgery. Preoperative magnetic resonance (MR) imaging did not show any abnormality in the patient. Computed tomography (CT) images taken immediately after the surgery did not show any intracranial hematoma and other abnormal findings. However, the patient did not recover from the general anesthesia, and hemorrhage in the left occipital lobe was detected by CT performed a day after the surgery. The location of the hematoma was markedly distant from the trajectory of DBS leads. Evacuation of the hematoma under general anesthesia was immediately performed. Results As an intraoperative finding, we noted the presence of abnormal vessels inside the hematoma in the occipital lobe. Tissue specimens including the abnormal vessels were obtained for histopathological analysis, results of which led to the diagnosis was AVM. Conclusion Despite its low incidence, we would like to advise that such a type of hemorrhage could occur and measures should be taken to prevent its occurrence as much as possible. Preoperative detection of abnormal vessels by MR angiography and/or CT angiography might be helpful. Moreover, paying close attention to the possible leakage of cerebrospinal fluid during surgery might be important.

We report a case of a cervical carotid artery pseudoaneurysm with contralateral severe stenosis, treated using a covered stent. A 79-year-old man admitted for a splenic artery aneurysm presented a pulsatile mass on the right side of his neck and lower cranial nerve palsy after misinsertion of a central venous line into the right carotid artery. MRI revealed a huge thrombosed aneurysm (30 mm×25 mm) in the right common carotid artery (CCA). We planned an aneurysmectomy and CCA interposition with a vascular graft. However the aneurysm continued to expand. We considered that it was difficult to expose the internal carotid artery (ICA) by a direct surgical technique, and therefore carried out placement of a covered stent over the orifice of the aneurysm using an endovascular surgical technique. Following placement of the covered stent, subsequent contrast-enhanced CT revealed leakage of contrast material into the aneurysm. An additional bare stent was placed into the proximal end of the covered stent at 15 days after the initial treatment. Angiography demonstrated no leakage of the contrast material. Following the second treatment, the pulsatile mass was reduced in size. Lower cranial nerve palsy remained but had slightly improved. We described the case of a huge cervical carotid pseudoaneurysm that was successfully treated using a covered stent.

Objectives. The aims of this study were to clarify the direction and degree of brain shift, and to determine the predictive factors for a brain shift during deep brain stimulation (DBS) of the subthalamic nucleus (STN). Materials and Methods. To evaluate the brain shift during bilateral STN-DBS, the position of the anterior commissure (AC), posterior commissure (PC), midcommissure point (MC), and tip of the frontal lobe and anterior horn of the lateral ventricle were calculated pre- and poststereotactic operations in the three-dimensional direction employing special software (Leksell SurgiPlan). To determine the predictive factors for a brain shift, patient's age, operation hours, width of the third ventricle, bicaudate index (BCI), and cella media index (CMI) were compared with the shift of MC. Results. In 50 patients, the MC shifted mainly in the posterior direction (y-axis: 1.27 ± 0.7 mm), and the shifts in the inferior direction (z-axis: 0.11 ± 0.43 mm) and lateral direction (x-axis: 0.02 ± 0.39 mm) were small. The shift of the MC in the posterior direction correlated well with the shift of the tip of the anterior lobe and anterior horn. Among the predictive factors examined, namely, the patient's age, operation hours, width of the third ventricle, BCI, and CMI, only the CMI showed a correlation with the shift of the MC (r = 0.42, p

Objective: Autonomic nervous system impairment is an untoward symptom that is typically observed in advanced Parkinson’s disease (PD) patients. However, details of the effects of subthalamic nucleus deep brain stimulation (STN-DBS) on the autonomic nervous system remain unclear. Methods: Twenty-eight patients with advanced PD (12 males and 16 females) who underwent bilateral STN-DBS and 13 age-matched healthy controls were included in this study. We analyzed the dynamic cardiovascular autonomic function regulating the R-R interval and blood pressure by spectral and transfer function analyses of cardiovascular variability before and after STN-DBS. Results: Vagally mediated arterial-cardiac baroreflex function improved after STN-DBS compared to that before STN-DBS (p < 0.05). However, there were no statistically significant differences in the results of the comparison of vagally mediated arterial-cardiac baroreflex function between on-stimulation and off-stimulation. Conclusions: The vagal component in cardiac autonomic dysfunction associated with PD is expected to improve after STN-DBS. We considered that the patients improved their lifestyle; in particular, increasing the amount of exercise by STN-DBS and the best pharmachological treatment may have positive effects on parasympathetic activities.

Background: In well-designed multicenter studies, the protocol of continuing motor cortex stimulation (MCS) temporarily for 3–6 weeks was employed with rehabilitation therapy, and these studies showed some recovery of motor weakness in post-stroke patients. Objectives: We aimed to clarify the effects of long-term MCS and the optimal stimulation conditions to improve motor weakness in post-stroke patients. Methods: We applied chronic MCS in 6 post-stroke pain patients with motor weakness. We then examined the correlation between the duration of daily MCS applied over 6 months and motor function assessed on the basis of the Fugl-Meyer Assessment (FMA) score of the patients. Results: In the 6 patients with motor weakness, the FMA score of the upper extremity increased in 4 patients who underwent daily MCS for less than 4 h. On the other hand, 2 patients who continued excessive MCS to control their complicating post-stroke pain showed decreased FMA scores and worsened motor function owing to their increased rigidity and/or spasticity. These 2 patients recovered their motor function after their daily MCS was restricted to less than 4 h. Conclusions: These findings indicate that MCS could be a new therapeutic approach to improving motor performance after stroke by attenuating rigidity and/or spasticity. However, it may be important to define the appropriate number of hours and conditions of daily MCS.

Background: Perinatal anoxia rarely causes myoclonus as the main neurologic abnormality. The exact neuronal mechanism underlying myoclonus induced by perinatal anoxia remains unknown. Some studies have indicated that the development of involuntary movements may be related to the maturation of the thalamus after birth. Objectives and Methods: Here, we describe the first case of a patient who developed action myoclonus after experiencing perinatal anoxia and was successfully treated by chronic deep brain stimulation (DBS) of the thalamus (thalamic DBS). Results andConclusion: The effectiveness of chronic thalamic DBS in this patient supports the concept of involvement of the thalamus in postperinatal anoxic myoclonus.

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, p0.01) and Case 2 (r = 0.807, p0.01). 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.

Introduction. The term “camptocormia” describes a forward-flexed posture. It is a condition characterized by severe frontal flexion of the trunk. Recently, camptocormia has been regarded as a form of abdominal segmental dystonia. Deep brain stimulation (DBS) is a promising therapeutic approach to various types of movement disorders. The authors report the neurological effects of DBS to the bilateral globus pallidum (GPi) in three cases of disabling camptocormia.

We applied chronic deep brain stimulation (DBS) of the thalamic nucleus ventralis caudalis (Vc) for the treatment of peripheral deafferentation pain. The subjects included 11 cases of phantom limb pain and 7 of root or nerve injury pain without phantom sensation. In the phantom limb pain patients, the spike density markedly increased in the same area of the Vc where microstimulation induced paresthesia in the part with phantom sensation. Reorganization of the receptive field representation within the Vc was also demonstrated by microrecording and microstimulation. In the root or nerve injury pain patients with severe allodynia and without phantom sensation, oscillating neural hyperactivity appeared when the allodynia was induced during single-cell recording in the Vc. In both groups stimulation of these areas with the DBS electrode was useful for achieving pain reduction. Inhibition of spinothalamic tract neurons, restoration of the original receptive field representation and modulation of thalamocortical rhythmic oscillations are proposed to play important roles in a possible mechanism of Vc-DBS for the treatment of deafferentation pain.

Spinal cord stimulation (SCS) is used to treat for several types of intractable pain syndromes, but it is not commonly used for treating post-stroke pain. Therefore, in this study, we analyzed the effects of SCS in patients with post-stroke pain. Neurological imaging and pharmacological analysis using thiopental, ketamine and morphine tests were conducted for 30 patients with post-stroke pain. For all patients, percutaneous electrodes were inserted under local anesthesia, and trial stimulation was performed for 5–7 days. If the patient experienced pain relief during the trial stimulation, a pulse generator was implanted. Of the 30 patients, 26 (87%) experienced satisfactory pain relief and underwent implantation. Ten patients received dual-octad lead SCS. The stimulation induced adequate paresthesia in all 10 patients. Nine (90%) of the 10 patients experienced satisfactory pain relief and opted for pulse generator implantation in order to proceed with the treatment. Upper cervical SCS was performed for patients with pain in not only the upper and lower extremities but also the face. Upper cervical SCS provided good paresthesia coverage and was effective for such patients. We think that patients with post-stroke pain may respond favorably to dual-octad lead SCS, and advancements in devices for SCS would further improve treatment outcomes for such patients.