Objectives: To investigate the clinical outcome of patients treated with chronic deep brain stimulation (DBS) of the centromedian nucleus (CM) for refractory epilepsy and to determine the location of active contacts. Methods: The outcome of CM stimulation was evaluated as percent seizure reduction compared to the baseline 3 months. To establish the location of active contacts, 27 leads were studied in 14 patients with refractory epilepsy. An analysis was conducted to reveal whether any coordinates of the center of the active contacts predicted percent seizure reduction. Results: With an average follow-up of 18.2 ± 5.6 months, the mean percent seizure reduction (n = 14) was 68 ± 22.4% (25-100%). Eleven of the 14 patients (78.6%) achieved >50% improvement in seizure frequency. Specifically, all 4 patients (100%) with generalized epilepsy (Lennox-Gastaut syndrome) and 7 of 10 patients (70%) with multilobar epilepsy showed >50% reduction in seizure frequency. The mean coordinates of the center of the active contact were located in the superior part of the anterior ventrolateral CM. The calculated coordinates of laterality from midline (x), anterior-posterior (y) and height (z) from the posterior commissure did not correlate with seizure outcome measured by percent seizure reduction. However, the locations of active contacts used during chronic CM stimulation in multilobar epilepsy were identified more dorsal to those used in generalized epilepsy. Conclusions: Chronic CM stimulation is a safe and effective means in the treatment of refractory epilepsy.

Background/Objectives: Although motor cortex stimulation (MCS) has been used for more than 20 years in the treatment of chronic neuropathic pain, there is still a debate about the efficacy of MCS. Methods: To investigate the long-term results and the factors associated with the long-term success of chronic MCS, 21 patients who underwent MCS trial were classified as having central poststroke pain, central pain after spinal cord injury (SCI) and peripheral neuropathic pain, and we investigated the clinical factors associated with long-term success and degree of pain relief. Results: Of the 21 patients, 16 (76.2%) had a successful trial and underwent chronic MCS. In the long-term follow-up (53 ± 39 months), only the diagnosis (central poststroke pain and peripheral neuropathic pain) was associated with long-term success defined as >30% pain relief compared with baseline (p < 0.05, χ² test). The difference in pain relief was not significant in patients having SCI pain (p > 0.05, 1-way ANOVA). The other variables did not show any significant influence in the long-term success and degree of pain relief (p > 0.05, 1-way ANOVA). Conclusions: MCS was more effective in the treatment of chronic neuropathic pain of central poststroke pain and peripheral neuropathic pain types than in the treatment of SCI pain in the long-term follow-up.

Twiddler's syndrome is an uncommon hardware complication involving the lead and pulse generators in cardiac pacemakers and defibrillators, deep brain stimulators, and vagal nerve stimulators. However, until very recently, it had not been reported in spinal cord stimulation (SCS). Considering the incidence of hardware complications of spinal cord stimulation, there may be an underreporting of Twiddler's syndrome due to lack of awareness. Two cases of Twiddler's syndrome as a hardware complication of SCS were identified between 2005 and 2015. One patient with hardware failure due to Twiddler's syndrome refused to have a revision surgery. The other patient who had a lead migration associated with coiling of the lead and twisting of pulse generator needed a revision surgery. Twiddler's syndrome in patients treated with SCS is an uncommon but important adverse event. Awareness of characteristic presentation and radiologic finding is essential in the identification of Twiddler's syndrome in SCS.

Background: Dorsal root entry zone (DREZ) lesioning has been reported to be effective for phantom limb pain caused by brachial plexus avulsion pain. Most reports on DREZ lesioning for brachial plexus avulsion pain have focused on the results of pain relief without a detailed description of phantom sensations following DREZ lesioning. Materials and Methods: Two patients (1 with amputation and the other nonamputated) with chronic intractable phantom limb pain caused by brachial plexus avulsion underwent DREZ lesioning on the avulsed segments of the cervical spinal cords. Changes of the phantom limb were observed. Results: Immediately following DREZ lesioning, the phantom limb pain disappeared in the amputee, the phantom arm was shortened and the phantom hand disappeared. The other patient with the nonamputated arm reported an immediate 50% reduction in the size of the phantom hand, and pain relief was up to 70% of the preoperative phantom limb pain. There was no further change in the phantom arm and hand during the follow-up of 1.5-2 years. Conclusions: The phantom arms and hands showed a prompt shortening and reduction in size, rather than a disappearance, following successful DREZ lesioning in patients with chronic phantom limb pain caused by brachial plexus avulsion.

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