Despite optimal pharmacotherapy and cognitive-behavioral treatments, a proportion of patients with obsessive-compulsive disorder (OCD) remain refractory to treatment. Neurosurgical ablative or nondestructive stimulation procedures to treat these refractory patients have been investigated. However, despite the potential benefits of these surgical procedures, patients show significant surgery-related complications. This preliminary study investigated the use of bilateral thermal capsulotomy for patients with treatment-refractory OCD using magnetic resonance-guided focused ultrasound (MRgFUS) as a novel, minimally invasive, non-cranium-opening surgical technique. Between February and May 2013, four patients with medically refractory OCD were treated with MRgFUS to ablate the anterior limb of the internal capsule. Patients underwent comprehensive neuropsychological evaluations and imaging at baseline, 1 week, 1 month and 6 months following treatment. Outcomes were measured with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the Hamilton Rating Scale for Depression (HAM-D) and the Hamilton Rating Scale for Anxiety (HAM-A), and treatment-related adverse events were evaluated. The results showed gradual improvements in Y-BOCS scores (a mean improvement of 33%) over the 6-month follow-up period, and all patients showed almost immediate and sustained improvements in depression (a mean reduction of 61.1%) and anxiety (a mean reduction of 69.4%). No patients demonstrated any side effects (physical or neuropsychological) in relation to the procedure. In addition, there were no significant differences found in the comprehensive neuropsychological test scores between the baseline and 6-month time points. This study demonstrates that bilateral thermal capsulotomy with MRgFUS can be used without inducing side effects to treat patients with medically refractory OCD. If larger trials validate the safety, effectiveness and long-term durability of this new approach, this procedure could considerably change the clinical management of treatment-refractory OCD.
OBJect The authors report different MRI patterns in patients with essential tremor (ET) or obsessive-compulsive disorder (OCD) after transcranial MR-guided focused ultrasound (MRgFUS) and discuss possible causes of occasional MRgFUS failure. MetHODS Between March 2012 and August 2013, MRgFUS was used to perform unilateral thalamotomy in 11 ET patients and bilateral anterior limb capsulotomy in 6 OCD patients; in all patients symptoms were refractory to drug therapy. Sequential MR images were obtained in patients across a 6-month follow-up period. reSultS For OCD patients, lesion size slowly increased and peaked 1 week after treatment, after which lesion size gradually decreased. For ET patients, lesions were visible immediately after treatment and markedly reduced in size as time passed. In 3 ET patients and 1 OCD patient, there was no or little temperature rise (i.e., < 52°C) during MRgFUS. Successful and failed patient groups showed differences in their ratio of cortical-to-bone marrow thickness (i.e., skull density). cOncluSiOnS The authors found different MRI pattern evolution after MRgFUS for white matter and gray matter. Their results suggest that skull characteristics, such as low skull density, should be evaluated prior to MRgFUS to successfully achieve thermal rise.Clinical trial registration nos. NCT01932463 (for ET) and NCT01986296 (for OCD) (ClinicalTrials.gov) http://thejns.org/doi/abs/10.3171/2014.8.JNS132603Key WOrDS MR-guided focused ultrasound; thalamotomy; capsulotomy; skull density; essential tremor; functional neurosurgery; obsessive-compulsive disorder aBBreViatiOnS ALIC = anterior limb of the internal capsule; ET = essential tremor; MRgFUS = magnetic resonance-guided focused ultrasound; MRI = magnetic resonance imaging; OCD = obsessive-compulsive disorder; Vim = ventral intermediate.
N europathic pain is often severe, and it can afflict patients for their entire lifetime. It can be caused by direct damage to the nervous system, and by neuronal degeneration. 7,8 Patients with degenerative diseases such as Parkinson's disease or dementia may experience neuropathic pain as a complication. Many studies have found that neuropathic pain can be induced by indirect nerve damage, but the mechanisms have not yet been clearly established. 7,8,29 The symptoms of neuropathic pain differ among patients, making treatment difficult.31 Although many studies of neuropathic pain and its control have been conducted, the mechanisms behind neuropathic pain are still not clear.Motor cortex stimulation (MCS) is a treatment modality used to modulate neuropathic pain by electrical stimulation. It was introduced in 1991 by Tsubokawa et al. and has since been used in clinical practice.46,47 MCS has advantages for clinicians and patients: MCS is simpler and easier to implement for pain modulation than other surgical methods, such as direct nerve stimulation and neurectomy, and can be considered an alternative for pain control. Among the many modalities involving electrical obJective Neuropathic pain is often severe. Motor cortex stimulation (MCS) is used for alleviating neuropathic pain, but the mechanism of action is still unclear. This study aimed to understand the mechanism of action of MCS by investigating pain-signaling pathways, with the expectation that MCS would regulate both descending and ascending pathways. methods Neuropathic pain was induced in Sprague-Dawley rats. Surface electrodes for MCS were implanted in the rats. Tactile allodynia was measured by behavioral testing to determine the effect of MCS. For the pathway study, immunohistochemistry was performed to investigate changes in c-fos and serotonin expression; micro-positron emission tomography (mPET) scanning was performed to investigate changes of glucose uptake; and extracellular electrophysiological recordings were performed to demonstrate brain activity. results MCS was found to modulate c-fos and serotonin expression. In the mPET study, altered brain activity was observed in the striatum, thalamic area, and cerebellum. In the electrophysiological study, neuronal activity was increased by mechanical stimulation and suppressed by MCS. After elimination of artifacts, neuronal activity was demonstrated in the ventral posterolateral nucleus (VPL) during electrical stimulation. This neuronal activity was effectively suppressed by MCS. coNclusioNs This study demonstrated that MCS effectively attenuated neuropathic pain. MCS modulated ascending and descending pain pathways. It regulated neuropathic pain by affecting the striatum, periaqueductal gray, cerebellum, and thalamic area, which are thought to regulate the descending pathway. MCS also appeared to suppress activation of the VPL, which is part of the ascending pathway.
Dural arteriovenous fistula (AVF) is very rare, acquired lesion that may present with intracranial hemorrhage or neurological deficits. The etiology is not completely understood but dural AVF often has been associated with thrombosis of the involved dural sinuses. To our knowledge, this is the first well documented intracranial hemorrhage case caused by dural AVF following microvascular decompression for hemifacial spasm. A 49-year-old male patient had left microvascular decompression of anterior inferior cerebellar artery via retrosigmoid suboccipital craniotomy. The patient was in good condition without any residual spasm or surgery-related complications. However, after 10 months, he suffered sudden onset of amnesia and dysarthria. Computed tomography and magnetic resonance imaging revealed the presence of dural AVF around the left transverse-sigmoid sinus. The dural AVF was treated with Onyx® (ev3) embolization. At the one-year follow up visit, there were no evidence of recurrence and morbidity related to dural AVF and its treatment. This case confirms that the acquired etiology of dural AVF may be associated with retrosigmoid suboccipital craniotomy for hemifacial spasm, even though it is an extremely consequence of this procedure.
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