Accuracy of Boltless Frame-Based Stereo-Electroencephalography Electrode Implantation.

BACKGROUND AND OBJECTIVES: Boltless implantation of stereo-electroencephalography electrode is a useful alternative especially when anchor bolt is not available such as in country with limited resources or is less appropriate such as placement in patients with thin skull or at the occiput area, despite some drawbacks including potential dislodgement. While the accuracy of implantation using anchor bolt is well-studied, data on boltless implantation remain scarce. This study aimed to reveal the accuracy, permissible error for actual placement of electrodes within the grey matter, and delayed electrode dislodgement in boltless implantation. METHODS: A total of 120 electrodes were implanted in 15 patients using a Leksell Stereotactic G Frame with each electrode fixed on the scalp using sutures. Target point error was defined as the Euclidean distance between the planned target and the electrode tip on immediate postimplantation computed tomography. Similarly, delayed dislodgement was defined as the Euclidean distance between the electrode tips on immediate postimplantation computed tomography and delayed MRI. The factors affecting accuracy were evaluated using multiple linear regression. The permissible error was defined as the largest target point error that allows the maximum number of planned gray matter electrode contacts to be actually placed within the gray matter as intended. RESULTS: The median (IQR) target point error was 2.6 (1.7-3.5) mm, and the permissible error was 3.2 mm. The delayed dislodgement, with a median (IQR) of 2.2 (1.4-3.3) mm, was dependent on temporal muscle penetration (P = 5.0 × 10-4), scalp thickness (P < 5.1 × 10-3), and insertion angle (P = 3.4 × 10-3). CONCLUSION: Boltless implantation of stereo-electroencephalography electrode offers an accuracy comparable to those using anchor bolt. During the planning of boltless implantation, target points should be placed within 3.2 mm from the gray-white matter junction and a possible delayed dislodgement of 2.2 mm should be considered.

Characteristics of Changes in Intrathecal Baclofen Dosage over Time due to Causative Disease.

Intrathecal baclofen (ITB) therapy effectively treats spasticity caused by brain or spinal cord lesions. However, only a few studies compare the course of treatment for different diseases. We investigated the change in daily dose of baclofen per year and its associated adverse events in patients presenting with the three most common etiologies at our institute: hereditary spastic paraplegia, cerebral palsy, and spinal cord injury. The ITB pumps were implanted from July 2007 to August 2019, with a mean follow-up period of 70 months. In patients with hereditary spastic paraplegia, baclofen dosage was reduced after eight years following ITB introduction, and the treatment was terminated in one patient owing to disease progression. In patients with cerebral palsy, the dosage increased gradually, and became constant in the 11th year. Patients with spinal cord injury gradually increased their baclofen dosage throughout the entire observation period. Severity and adverse event rates were higher in patients with cerebral palsy than in others. The degree and progression of spasticity varied depending on the causative disease. Understanding the characteristics and natural history of each disease is important when continuing ITB treatment.

Endovascular Treatment for Middle Cerebral Artery Aneurysms: Single-Center Experience and Review of Literatures.

Objective: The efficacy of endovascular treatment for middle cerebral artery (MCA) aneurysms remains controversial. However, recent studies have reported the safety of endovascular treatment for MCA aneurysms. In this study, we studied the efficacy and clinical outcomes of endovascular treatment for MCA aneurysms in our hospital and the morphology and anatomy of MCA aneurysms that were suitable for endovascular treatment. Methods: We retrospectively analyzed 26 cases of MCA aneurysms which had undergone endovascular treatment at our institution between January 2015 and October 2018. We studied sizes and shapes of the aneurysms, clinical and angiographical outcomes one year after the treatment, and complications in these 26 patients. We also compared the differences in these parameters of the 26 patients with those of 61 other patients who were treated with clipping during the same period. Results: The median aneurysm size was 6.1 mm (1.8-29.9 mm), with the shapes of the aneurysms irregular in 8, and round in the other 18 cases. Four cases (15.4%) had ruptured aneurysms. All aneurysms were treated with assist techniques; 8 (30.8%) were treated by stent-assisted technique and 18 (69.2%) were treated by balloon-assisted technique and endovascular treatment was successfully performed in all (100%) cases. While the aneurysms were completely obliterated in 22 of them (84.6%), the remaining 4 cases (15.4%) had neck remnants. We observed periprocedural complications in 5 of the 26 (19.2%) aneurysms, all of which were transient and completely recovered during the follow-up period. The efficacy and complication rates were not different from the MCA aneurysms treated with clipping. All MCA aneurysms arising from the M1 trunk were treated with endovascular treatment, and those with a round shape with the axis not deviating from M1 were also treated with endovascular treatment. Conclusion: Endovascular treatment for MCA aneurysms is safe and effective together with adjunctive techniques such as balloon-assisted technique or stent-assisted technique. Thus, M1 trunk aneurysms and MCA bifurcation aneurysms with a round shape along the same axis of MCA may be good indications for endovascular treatment. However, long-term clinical and angiographical outcomes remain unknown. Thus, further studies are needed to address the existing limitations.

Burst Spinal Cord Stimulation for the Treatment of Cervical Dystonia with Intractable Pain: A Pilot Study.

Pain is the most common and disabling non-motor symptom in patients with cervical dystonia. Here, we report four patients with painful cervical dystonia in whom burst spinal cord stimulation (SCS) in the cervical region produced sustained and significant improvements in both dystonic pain and motor symptoms. Further studies need to be performed to investigate the clinical efficacy of burst SCS for patients with cervical dystonia.

Surgical Treatment of Brain Metastasis of Extramammary Paget's Disease: A Case Report.

Extramammary Paget's disease (EMPD) is a rare form of neoplasm. Metastasis of EMPD to locations other than lymph nodes and intra-epithelial regions is rare; there are a limited number of case reports of metastases to the liver, lung, bone, and brain. We present a rare case of EMPD that metastasized to the brain and was treated with surgical resection. A 66-year-old man presented with a small palpable mass in the scrotum. After 5 years of observation, he was diagnosed with EMPD that metastasized to the lymph nodes and lung. Tumor resection and postoperative chemotherapy were performed. Six months after the last chemotherapy treatment, he presented with a right temporal lobe tumor and underwent surgical resection. Histopathological analysis revealed brain metastasis of EMPD. Three months after surgery, magnetic resonance imaging (MRI) showed local tumor recurrence, and intensity modulated radiation therapy (IMRT) (45 Gy/15 Fr) was performed. Although the metastatic brain tumor was well controlled, the primary tumor progressed. He was provided best supportive care and died 5 months after brain tumor resection. In this report, we present a rare case of brain metastasis of EMPD, treated with surgical resection, and histopathologically confirmed to be metastatic EMPD.

Stereotactic Lesioning of the Thalamic Vo Nucleus for the Treatment of Writer's Cramp (Focal Hand Dystonia).

Writer's cramp (focal hand dystonia) is a sporadic focal dystonia that affects a specific part of the upper limb causing excessive co-contraction of antagonistic muscles. It usually presents as a task-specific dystonia, including, among others, writing of a character or playing a musical instrument. Although treatments for writer's cramp exist, medical therapy often results in unsatisfactory outcomes in patients with this type of dystonia. However, accumulating evidence suggests that long-term and complete remission of various types of focal hand dystonia can be achieved with stereotactic ablation or deep brain stimulation of the thalamic ventral-oralis complex (Vo) nucleus, which includes both the ventralis oralis posterior and anterior nuclei of the thalamus. Following the striking therapeutic success of Vo thalamotomy in patients with medically-refractory writer's cramp, we here introduce the use of stereotactic lesioning of the thalamic Vo nucleus for the treatment of this focal type of dystonia. Our findings identified patients with disabling writer's cramp (i.e., it prevents their success in their professional careers) to be good candidates for positive outcome with this surgical technique.