Chul Bum Cho

Long-term outcome of anterior thalamic nucleus stimulation for intractable epilepsy.

Background: Many patients with epilepsy have persistent seizures despite treatment with maximal antiepileptic drug therapy and are not candidates for resective brain surgery. Objectives: We investigated the effectiveness of seizure reduction after anterior thalamic nucleus (ATN) stimulation in patients with intractable epilepsy undergoing deep brain stimulation (DBS) of the thalamus. Methods: Patients included in this study had poorly controlled seizures, despite anticonvulsant medication, and were not candidates for surgical resection of an identifiable seizure focus. Fifteen patients with medically refractory epilepsy underwent the placement of bilateral DBS electrodes in the anterior thalamus. The seizure frequency was monitored and compared with the preimplantation baseline. Results: The treatment demonstrated a statistically significant decrease in the seizure frequency, with a mean reduction of 70.4% (mean follow-up, 27 months). Two of the patients had a remarkable reduction of seizure frequency. Conclusion: It seems to be important that the short-term outcome of ATN DBS reflects the long-term outcome directly. The correlation between the seizure type, characteristics and anticonvulsant effects of ATN DBS did not exhibit significance because of the small number of cases. Therefore, a longer-term follow-up with a larger group of patients is required to fully evaluate the safety and effectiveness of this treatment modality.

Stereotactic Radiosurgery with the CyberKnife for Pituitary Adenomas

OBJECTIVE In recent years, CyberKnife has emerged as an important treatment modality in the management of pituitary adenomas. Treatment results after performing CyberKnife and the complications of this procedure are reviewed. METHODS Twenty-six patients with pituitary adenomas received stereotactic radiosurgery with the CyberKnife (CKRS). The follow-up periods ranged from 7 months to 47 months (mean+/-SD : 30+/-12.7 months). The patients consisted of 17 with non-functioning adenomas, 3 with prolactinomas and 6 with acromegaly. The change in the tumor volume, visual acuity, hormonal function, and complications by this therapy were analyzed in each case. RESULTS The tumor control rate was 92.3%. Hormonal function was improved in all of the 9 (100%) functioning adenomas. Hormonal normalization was observed in 4 of the 9 (44%) patients with a mean duration of 16 months. In two patients (7.6%), visual acuity worsened due to cystic enlargement of the tumor after CKRS. No other complications were observed. CONCLUSION CyberKnife is considered safe and effective in selected patients with pituitary adenomas. However, longer follow-up is required for a more complete assessment of late toxicity and treatment efficacy.

Anterior Lumbar Interbody Fusion with Stand-Alone Interbody Cage in Treatment of Lumbar Intervertebral Foraminal Stenosis : Comparative Study of Two Different Types of Cages

OBJECTIVE This retrospective study was performed to evaluate the clinical and radiological results of anterior lumbar interbody fusion (ALIF) using two different stand-alone cages in the treatment of lumbar intervertebral foraminal stenosis (IFS). METHODS A total of 28 patients who underwent ALIF at L5-S1 using stand-alone cage were studied [Stabilis(R) (Stryker, Kalamazoo, MI, USA); 13, SynFix-LR(R) (Synthes Bettlach, Switzerland); 15]. Mean follow-up period was 27.3 +/- 4.9 months. Visual analogue pain scale (VAS) and Oswestry disability index (ODI) were assessed. Radiologically, the change of disc height, intervertebral foraminal (IVF) height and width at the operated segment were measured, and fusion status was defined. RESULTS Final mean VAS (back and leg) and ODI scores were significantly decreased from preoperative values (5.6 +/- 2.3 --> 2.3 +/- 2.2, 6.3 +/- 3.2 --> 1.6 +/- 1.6, and 53.7 +/- 18.6 --> 28.3 +/- 13.1, respectively), which were not different between the two devices groups. In Stabilis(R) group, postoperative immediately increased disc and IVF heights (10.09 +/- 4.15 mm --> 14.99 +/- 1.73 mm, 13.00 +/- 2.44 mm --> 16.28 +/- 2.23 mm, respectively) were gradually decreased, and finally returned to preoperative value (11.29 +/- 1.67 mm, 13.59 +/- 2.01 mm, respectively). In SynFix-LR(R) group, immediately increased disc and IVF heights (9.60 +/- 2.82 mm --> 15.61 +/- 0.62 mm, 14.01 +/- 2.53 mm --> 21.27 +/- 1.93 mm, respectively) were maintained until the last follow up (13.72 +/- 1.21 mm, 17.87 +/- 2.02 mm, respectively). The changes of IVF width of each group was minimal pre- and postoperatively. Solid arthrodesis was observed in 11 patients in Stabilis group (11/13, 84.6%) and 13 in SynFix-LR(R) group (13/15, 86.7%). CONCLUSION ALIF using stand-alone cage could assure good clinical results in the treatment of symptomatic lumbar IFS in the mid-term follow up. A degree of subsidence at the operated segment was different depending on the device type, which was higher in Stabilis(R) group.

Thalamic Deep Brain Stimulation for Writer's Cramp.

Writers cramp is a type of idiopathic focal hand dystonia characterized by muscle cramps that accompany execution of the writing task specifically. There has been renewed interest in neurosurgical procedures for the treatment of dystonia over the past several years. In particular, deep brain stimulation (DBS) has received increasing attention as a therapeutic option for patients with dystonia. However, to date, limited reporters made investigations into DBS in relation to the Writers cramp. In this case, unilateral Ventro-oralis complex (Vo) DBS resulted in a major improvement in patients focal dystonic movement disorders. Her post-operative Burke-Fahn-Marsden Dystonia Rating (BFMDR) scale demonstrated 1 compared with pre-operative BFMDR scale 4. We conclude that thalamic Vo complex DBS may be an important neurosurgical therapeutic option for Writers cramp.

Spontaneous Bilateral Supratentorial Subdural and Retroclival Extradural Hematomas in Association with Cervical Epidural Venous Engorgement

We describe a case of 36-year-old man who presented with a subacute headache preceded by a 1-month history of posterior neck pain without trauma history. Head and neck magnetic resonance imaging (MRI) studies disclosed bilateral supratentorial subdural and retroclival extradural hematomas associated with marked cervical epidural venous engorgement. Cerebral and spinal angiography disclosed no abnormalities except dilated cervical epidural veins. We performed serial follow-up MRI studied to monitor his condition. Patients symptoms improved gradually. Serial radiologic studies revealed gradual resolution of pathologic findings. A 3-month follow-up MRI study of the brain and cervical spine revealed complete resolution of the retroclival extradural hematoma, disappearance of the cervical epidural venous engorgement, and partial resolution of the bilateral supratentorial subdural hematoma. Complete resolution of the bilateral supratentorial subdural hematoma was confirmed on a 5-month follow-up brain MRI. The diagnosis and possible mechanisms of this rare association are discussed.

Elongated Styloid Process as a Cause of Transient Ischemic Attacks

A 49-year-old man had been experiencing transient right-sided weakness during neck rotation and flexion to the left for 1 year. On hospital admission, a neurological examination revealed no deficits. Initialmagnetic resonance imaging of the brainwas unremarkable. The first computed tomographic (CT) angiographyof thebrain and neck revealed no abnormal findings. Catheter cerebral angiography,performedwiththepatient’sheadturnedtothe left (Figure1), demonstrated a filling defect fromwhat appears to be an extrinsic compression.ThesecondCTangiographyof thebrainandneckperformed with the patient’s head turned to the left (Figure 2 and Figure 3) revealed a left cervical internal carotid artery (ICA) compression due to an elongated styloid process. The elongated styloidprocesswasremovedduringsurgery,afterwhichthepatienthad a satisfactory recovery. Postoperative CT angiography of the brain and neck (Figure 4) revealed that the left cervical ICA was free of compression. This case suggests the usefulness of dynamic catheter and CT angiography for the diagnosis of an elongated styloid process as a cause of transient ischemic attack.

Suppressed GABAergic signaling in the zona incerta causes neuropathic pain in a thoracic hemisection spinal cord injury rat model

OBJECTIVE Suppression of the gamma-aminobutyric acid (GABA)ergic activity of the zona incerta (ZI) reportedly plays a role in neuropathic pain after spinal cord injury (SCI). A reduction in GABAergic signaling in the ZI of a thoracic hemisection-SCI rat model has been suggested, but not clearly demonstrated. Accordingly, our objective was to investigate whether GABAergic signals influence SCI-induced neuropathic pain. METHODS In vivo, we recorded and compared single-unit, neuronal activity between hemisection-SCI and sham-operated rat models. Furthermore, we analyzed neuronal activity in both models following treatment with either a GABAA receptor agonist (muscimol) or antagonist (bicuculline). RESULTS Rats that underwent hemisection SCI exhibited reduced hindpaw withdrawal thresholds, latencies, and decreased ZI neuronal activity compared with sham-operated controls. Importantly, muscimol treatment increased, whereas bicuculline decreased, the firing rates of the ZI neurons. The muscimol treated, hemisection-SCI rats also exhibited increased hindpaw withdrawal thresholds and latencies. CONCLUSIONS These data provide evidence that neuropathic pain after SCI is caused by decreased GABAergic signaling in the ZI. Furthermore, our data demonstrate that infusion of a GABAergic drug into the ZI could restore its inhibitory action and improve neuropathic pain behaviors.

Effect of optogenetic modulation on entopeduncular input affects thalamic discharge and behavior in an AAV2-α-synuclein-induced hemiparkinson rat model

OBJECTIVE Neuromodulation of the globus pallidus internus(GPi) alleviates Parkinsons disease symptoms. The primate GPi is homologous to the rat entopeduncular nucleus (EP). The aim of the present study was to determine if optogenetic modulation of the EP could alter parkinsonian behavior or thalamic discharge in a hemiparkinson rat model. METHODS We injected an adeno-associated virus type-2 expressing α-synuclein (AAV2-α-syn) into the substantia nigra pars compacta (SNc) of the right hemisphere and confirmed parkinsonian behavior using an amphetamine-induced rotation test. Then we injected activated or inhibited neurons, using the channelrhodopsin2 (ChR2)/halorhodopsin (NpHR) system in the EP of the hemiparkinson rat model and examined downstream effects in vivo. We assessed alterations in parkinsonian behaviors using the stepping and cylinder tests before, during, and after optogenetic stimulation. RESULTS Importantly, optogenetic inhibition of the EP improved parkinsonian motor behaviors. When we monitored thalamic neuronal activity following optogenetic neuromodulation in vivo, and we observed alterations in thalamic discharge The thalamic neuronal activity is increased for optogenetic inhibition stimulation, whereas decreased for optogenetic activation stimulation. CONCLUSIONS Taken together, our data demonstrate that optical neuromodulation of the EP can successfully control contralateral forelimb movement and thalamic discharge in an AAV2-α-synuclein-induced hemiparkinson rat model.

Striatal Glutamate and GABA after High Frequency Subthalamic Stimulation in Parkinsonian Rat

Objective High frequency stimulation (HFS) of the subthalamic nucleus (STN) is recognized as an effective treatment of advanced Parkinson’s disease. However, the neurochemical basis of its effects remains unknown. The aim of this study is to investigate the effects of STN HFS in intact and 6-hydroxydopamine (6-OHDA)-lesioned hemiparkinsonian rat model on changes of principal neurotransmitters, glutamate, and gamma-aminobutyric acid (GABA) in the striatum. Methods The authors examined extracellular glutamate and GABA change in the striatum on sham group, 6-OHDA group, and 6-OHDA plus deep brain stimulation (DBS) group using microdialysis methods. Results High-pressure liquid chromatography was used to quantify glutamate and GABA. The results show that HFS-STN induces a significant increase of extracellular glutamate and GABA in the striatum of 6-OHDA plus DBS group compared with sham and 6-OHDA group. Conclusion Therefore, the clinical results of STN-HFS are not restricted to the direct STN targets but involve widespread adaptive changes within the basal ganglia.

The usefulness of dual volume visualization (three-dimensional digital subtraction angiography and cross-sectional imaging) for surgical planning in treating intracranial meningiomas: a case series and technical report

OBJECTIVE In presurgical planning for intracranial meningiomas, the relationship between tumors and adjacent vasculature must be identified. The purpose of this study was to evaluate the usefulness of 3-dimensional digital subtraction angiography (3D-DSA) with dual-volume visualization (DVV). METHODS Between February 2013 and April 2016, 26 patients with intracranial meningiomas enrolled in this study. Two or 3 days before surgery, 3D-DSA with DVV was performed for presurgical planning. If necessary, the tumor was simultaneously embolized. RESULTS Vascular supply and disfiguration observed by preoperative 3D-DSA with DVV closely resembled those actually observed during surgery. All but 2 patients had total tumor resection (Simpson grade 1 or 2). Three of 26 patients had new neurologic deficits. CONCLUSIONS 3D-DSA with DVV may be useful for preoperative planning by allowing the surgeon to identify the relationship between a tumor and peritumoral vasculature before meningioma surgery. Young neurosurgeons with little experience may benefit most from this technique.