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OBJECTIVE Spinal cord stimulation (SCS) has been considered an ineffective procedure for patients with central poststroke pain (CPSP). However, recent case series that included small numbers of patients reported the possible efficacy of SCS as a treatment of CPSP. This multicenter retrospective study aimed to examine the outcomes of using SCS to treat patients with CPSP and to explore factors related to outcomes. METHODS The authors reviewed the medical records of patients with CPSP who underwent SCS to collect data regarding their background, surgical information, and outcomes of SCS at trial stimulation and last follow-up after long-term implantation in six study centers. Outcomes were evaluated with a pain score for intensity (range 0–10) and the Patient Global Impression of Changes (PGIC) scale. Factors associated with outcomes were explored with univariable and multivariable analyses. RESULTS The authors collected data from a total of 166 patients (mean age 63.4 years; mean pain score at baseline 8.2). Of these patients, 163 underwent trial stimulation. The mean pain score decreased by 42.0%, 104 (64%) patients had ≥ 30% decrease in pain score, and 96 (59%) reported much or very much improved condition on the PGIC scale at trial stimulation. Moreover, 106 (64%) patients underwent long-term implantation of SCS devices. The mean decrease in pain score was 41.4%, 63 (59%) patients continued to show ≥ 30% decrease in pain score at last follow-up, and 60 (56%) reported much or very much improved condition on the PGIC scale at last follow-up (median [range] follow-up period 24 [24–63] months). Eleven device-related complications and 10 permanent explantations were observed. Univariable and multivariable analyses suggested that young age, less sensory disturbance, implantation of cervical leads, treatment of upper-limb pain, and extensive treated regions were associated with satisfactory outcomes at last follow-up after long-term implantation. CONCLUSIONS These findings indicate that SCS may modestly benefit patients with CPSP. SCS has therapeutic potential for patients with intractable CPSP owing to the lower invasiveness of the SCS procedure and refractory nature of CPSP. Nevertheless, trial stimulation is necessary because of the high initial failure rate.

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.

Object The objective of this study was to evaluate the efficacy of chronic subthalamic nucleus (STN) stimulation for alleviating pain related to Parkinson disease (PD). Methods Among 163 consecutive patients undergoing STN stimulation, 69 were identified as experiencing pain preoperatively that was related to their PD. All 69 patients suffering from pain were followed up prospectively for 12 months after surgery. All patients described the severity of their pain according to a visual analog scale (VAS) preoperatively and at 2 weeks, 6 months, and 12 months postoperatively. Pain unrelated to PD was not studied. Results Several types of pain related to PD, the categories of which were based on a modification of 2 previous classifications (Ford and Honey), can occur in such patients: 1) musculoskeletal pain, 2) dystonic pain, 3) somatic pain exacerbated by PD, 4) radicular/peripheral neuropathic pain, and 5) central pain. The overall mean VAS score was significantly decreased postoperatively by 75% and 69% at 2 weeks and 6 months, respectively (p < 0.001). The mean VAS score at 12 months was also decreased by 80%, but 6 instances of pain (3 reports of somatic back pain and 3 reports of radicular/peripheral neuropathic pain) required additional spinal surgery to alleviate the pain severity. The results were analyzed using the Wilcoxon signed-rank test and demonstrated a significant reduction in VAS scores at all follow-up assessments (p < 0.001). Musculoskeletal pain and dystonic pain were well alleviated by STN stimulation. In contrast, somatic pain exacerbated by PD and peripheral neuropathic pain originating from lumbar spinal diseases, such as spondylosis deformans and/or canal stenosis, often deteriorated postoperatively despite attenuation of the patients' motor disability. Patients with central pain were poor responders. Conclusions This study found that STN stimulation produced significant improvement of overall pain related to PD in patients with advanced PD, and the efficacy continued for at least 1 year. The present results indicate that musculoskeletal pain and dystonic pain responded well to STN stimulation, but patients with back pain (somatic pain) and radicular/peripheral neuropathic pain originating from spinal disease have a potential risk for postoperative deterioration of their pain.

✓Beginning-of-dose motor deterioration (BDMD) is a complication of levodopa medications in Parkinson disease (PD) that is presumably caused by inhibitory effects of levodopa. Only limited experience of BDMD has been described in the literature. The authors report the case of a patient with PD who demonstrated a marked BDMD while being treated with standard levodopa medications. This 55-year-old woman had a 12-year history of PD and a 10-year history of levodopa treatment. Marked exacerbation of symptoms occurred 15 to 20 minutes after every dose of levodopa at 100 mg and lasted approximately 15 minutes. The PD symptoms, particularly tremor and rigidity, were exacerbated more markedly during this period than during the wearing-off deterioration. The BDMD could be controlled very well by subthalamic nucleus (STN) stimulation without any change in the regimen of levodopa medications. These observations suggest that the BDMD was inhibited by STN stimulation through a direct effect.

✓ Reversibility and adaptability are preferred features of long-term therapeutic deep brain stimulation (DBS). In such therapy, a permanent stimulating electrode with four contact points is placed at the stimulation site and, generally speaking, bipolar stimulation is induced by various pairs of adjacent contact points on one electrode. The stimulation sites are thus all located along the trajectory of the implanted electrode. In a patient with unilateral severe essential tremor, the authors implanted two electrodes side by side and parallel to each other in the unilateral thalamic ventralis intermedius nucleus. Using these electrodes, the authors were able to deliver current flow not only along the electrode trajectory, but also between the two electrodes in a direction parallel to the anterior commissure—posterior commissure line. Although individual stimulations, delivered by each of the two electrodes using all parameters and all stimulation points, were unable to stop the patient's tremor completely without adverse effects, the new stimulation method, in which electrical currents passed between the two electrodes, effected complete abolition of the tremor without adverse effects. With the aid of this method, one can use two electrodes, implanted in parallel and side by side, to achieve maximum efficacy and to reduce adverse effects in some instances of DBS therapy.

✓ Persistent hemiballismus after stroke is often difficult to treat. The ballistic movement is sometimes so violent that progressive exhaustion results. The authors report two such cases, which were successfully treated by chronic thalamic stimulation. The lesions responsible for the ballistic movement in these patients were located near the subthalamic nucleus and in the putamen, respectively. The thalamic nucleus ventrolateralis and nucleus ventralis intermedius were stimulated with 0.2 to 0.3 msec pulses at 50 to 150 Hz and 4 to 7 V continuously during the day. Several weeks later, complete control of the hemiballismus was achieved during stimulation. The improvement was clearly not attributable to spontaneous recovery, because ballistic movement reappeared after termination of the stimulation. The stimulation has remained effective for more than 16 months in both cases without any serious complications. Chronic thalamic stimulation appears to be useful for controlling persistent hemiballismus, as it is for other involuntary movement disorders.

✓ In order to determine adequate therapeutic approaches for cavernous malformations of the third ventricle, the authors reviewed a series of five such malformations managed at their institution and nine others reported in the literature. Four subgroups were identified in terms of the site of origin and could be characterized by different clinical manifestations: visual field defects and endocrine function deficits in patients with malformations in the suprachiasmatic region (six cases); symptoms caused by hydrocephalus in those with malformations in the foramen of Monro region (five cases); and deficits of short-term memory in those with malformations in the lateral wall (two cases) or of the floor of the third ventricle (one case). Unlike cavernous malformations at other locations, malformations of the third ventricle frequently demonstrated rapid growth (43%) and mass effects (71%). The surgical or autopsy findings suggested that the growth was attributable to repeated intralesional hemorrhages. Extralesional hemorrhage was also not uncommon, occurring in 29% of patients. Such tendencies require the adoption of a more aggressive approach to this particular group of cavernous malformations as compared to those in other locations. The risks of regrowth and extralesional hemorrhage appear to be reduced only by complete excision. The surgical approaches adopted should be aimed at providing the best access to the site where the malformation has arisen. The translamina terminalis approach for cavernous malformations in the suprachiasmatic region, the transventricular or transcallosal interfornicial approaches for those in the foramen of Monro region and the transvelum interpositum approach for those in the lateral wall or the floor of the third ventricle appear to be appropriate. In order to select the adequate surgical approach, precise diagnosis of the site of origin is crucial. In addition to neuroimaging techniques, the patient's initial symptoms provide valuable information.

✓ Analysis of the authors' experience over the last 10 years has indicated that excellent pain control has rarely been obtained by thalamic relay nucleus stimulation in patients with thalamic pain. In the present study, 11 patients with thalamic pain were treated by chronic stimulation of the precentral gyrus. In eight patients (73%), the stimulation system was internalized since excellent pain control was achieved during a 1-week test period of precentral gyrus stimulation. In contrast, no clear effect was noted or the original pain was even exacerbated by postcentral gyrus stimulation. The effect of precentral stimulation was unchanged in five patients (45%) for follow-up periods of more than 2 years. In the remaining three patients, the effect decreased gradually over several months. This outcome was significantly better than that obtained in an earlier series tested by the authors with thalamic relay nucleus stimulation (p < 0.05). The pain inhibition usually occurred at intensities below the threshold for production of muscle contraction (pulse duration 0.1 to 0.5 msec, intensity 3 to 8 V). When good pain inhibition was achieved, the patients reported a slight tingling or mild vibration sensation during stimulation projected in the same area of distribution as their pain. The authors discuss the possibility that, in deafferentation pain, sensory neurons below the level of deafferentation cannot exert their normal inhibitory influences toward deafferented nociceptive neurons because of the development of aberrant connections. Thus, while stimulation of the first- to third-order sensory neurons at the level of the thalamic relay nucleus or below cannot bring about good pain inhibition in patients with thalamic pain, activation of hypothetical fourth-order sensory neurons through precentral stimulation may be able to inhibit deafferented nociceptive neurons within the cortex. None of the patients developed either observable or electroencephalographic seizure activity.