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Radiofrequency lesioning surgery is primarily performed to treat Parkinson's disease, dystonia, and tremor. Its effects are similar to those of deep brain stimulation (DBS). However, Radiofrequency lesioning surgery has not been popularized, possibly due to the over-evaluation of its risks. The current most available targets for the treatment of movement disorders include ventral intermediate (Vim) nucleus, ventral oral (Vo) nucleus, and globus pallidus internus (GPi). Vim thalamotomy is available for Parkinsonian tremor, essential tremor, dystonic tremor, and other various kinds of tremor, and it is highly effective. Bilateral vim thalamotomy is feasible when properly performed on tiny lesions on the bilateral vim nucleus. Vo thalamotomy is mainly available for focal hand dystonia. The safety profile of bilateral Vo thalamotomy has not yet been established, but it is thought that it may lead to irreversible hypophonia and dysarthria. Pallidotomy is selected for treatment of dystonia and Parkinson's disease. Although unilateral pallidotomy is a safe procedure, it can cause medically refractory parkinsonism including postural reflex disturbance and gait disorder. Delayed infarction on the posterior limb of internal capsule is another major concern associated with pallidotomy and can lead to hemiparesis. Correct understanding is absolutely essential to ensure the safety of radiofrequency lesioning surgery.

Anatomical knowledge of target structures is essential in stereotactic functional neurosurgery. Thus, we created a three-dimensional(3D)atlas comprising frozen sections and histologically stained slides prepared from cadaveric brains. Herein, we describe the anatomical information of stereotactic functional neurosurgery targets gained from our atlas. The subthalamic nucleus(STN)was found to be clearly enclosed by neural fibers with high neuronal density. Based on our 3D models, the mean penetration length of deep brain stimulation leading into the STN was 6.6 mm. The globus pallidus was found to be clearly divided into the grobus pallidus externus(GPe)and internus(GPi)by its neural fibers, and the optic tract was located below the GPi. Although the thalamic lateral nuclear group(ventrooralis, ventrontermedius, and ventrocaudalis)could not be identified from either macroscopic frozen sections or MR images, these structures were clearly discernible from each other based on cell architecture(cell size and cell density)when viewed under a microscope. In contrast, distinguishing ventral and dorsal nuclei in humans is difficult. In addition to the main targets of the basal ganglia, we also investigated the anatomy of other targets in detail(posterior subthalamic area, pedunclopontine nucleus, nucleus accumbens, and nucleus basalis of Meynert). Overall, this anatomical knowledge from the atlas helps functional neurosurgeons interpret intraoperative microelectrode recording and MRI more precisely, helping facilitate more accurate surgeries.

Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements or postures. Currently, dystonia is defined as a network disorder involving the basal ganglia, cerebellum, thalamus, and sensorimotor cortex. Considering that it is refractory to medical therapy, functional neurosurgery is indispensable in the treatment strategy for dystonia. Functional neurosurgery may improve dystonic symptoms by suppressing abnormal neuronal activity in the motor loop network. Deep brain stimulation(DBS)of the globus pallidus internus(GPi)is a useful surgical treatment for genetically defined and primary dystonia involving the axial musculature. Thalamic ventral oral(Vo)nucleus surgery is recommended for cases of peripheral dystonia, such as writer's cramp and other occupational types of dystonia. However, pallidal DBS is less effective in cases of secondary dystonia, with the exception of tardive dystonia. Recent studies have reevaluated that ablation surgery is the last-resort treatment when DBS must be discontinued for certain conditions. Magnetic resonance-guided focused ultrasound(MRgFUS), a novel, incision-free, ablation technique, is currently used for the treatment of focal hand dystonia.

The globus pallidus internus(GPi)has evolved as a potential target for deep brain stimulation(DBS)in patients with advanced Parkinson's disease(PD). GPi stimulation has a significant impact on intractable hyperkinetic movement disorders. Optimal surgical procedures require a combination of image-based targeting and intraoperative microelectrode recording(MER)strategies. Provocation with stimulation through microelectrode or a DBS electrode is also crucial for refining the appropriate electrode position and obtaining a wide therapeutic window of stimulation parameters. In patients with PD, the best target for deep brain stimulation, whether subthalamic nucleus(STN)or the GPi, has been a subject of interest in recent medical literature. STN remains the preferred target for DBS in patients with advanced PD worldwide. In postoperative medication reduction, numerous data support that STN stimulation reduces the total dose of anti-parkinsonian drugs compared to GPi stimulation. However, GPi stimulation has shown a direct anti-dyskinetic effect, without reducing levodopa. Thus, GPi stimulation might be recommended for patients with neurocognitive or neuropsychiatric issues. GPi stimulation has a potential for treating hyperkinetic movement disorders. In patients with PD, STN stimulation is preferred worldwide; however, GPi stimulation has a clinical advantage only for select patients.

The basal ganglia(BG)is composed of four parallel loops: the motor, oculomotor, associative, and limbic loops. The motor loop starts from the cortex, travels through the BG and thalamus, and returns to the same area of the cortex with somatotopic organization. The striatum is the major input nucleus of the cortex, and the internal segment of the globus pallidus(GPi)is the main output nucleus. BG is explained by the direct and indirect pathways, and these excitatory or inhibitory pathways are used for several disease models. In Parkinson's disease(PD), dopamine deficiency acts on both direct and indirect pathways to cause the neuronal activity of GPi to becomes disinhibited. Pallidotomy, an effective surgery to improve Parkinsonism, aimed to destroy this hyperactive state. This is based on the rate model. However, a simian PD model with MPTP-treated monkeys exhibited increased GPi activity during effective stimulation of subtalamic nucleus(STN)-DBS, which makes it difficult to explain the pathophysiology of PD based only on the rate model. Instead, the alterative model is now widely prevailing. Local field potentials recorded from the DBS leads implanted in GPi and/or STN uncovered the abnormally synchronized activity in the β range(β oscillation)and abnormal co-synchronization between these nuclei, which is believed to be important in the pathophysiology of PD.

Accurate targeting to the sensorimotor territory of the globus pallidus internus (GPi), the subthalamic nucleus (STN), and the thalamic ventral intermediate nucleus (Vim) is crucial for the stereotactic neurosurgery of lesioning or implantation of a deep brain stimulation electrode. Intra-operative micro-electrode recording can aid in the localization of these structures. Neurons in the GPi are characterized by high-frequency tonic discharge. The STN has a high density of neurons that show irregular discharge. The majority of neurons in the sensorimotor territory of the GPi and STN exhibit neuronal responses to passive manipulation or active movement of the limbs and orofacial parts, and they are somatotopically arranged. Neurons responding to movements of the legs, arms, and face were found along the dorsal-ventral axis in the posterolateral GPi and along the medial-lateral axis in the posterolateral STN. Similarly, in the lateral part of the thalamic Vim nucleus, most neurons exhibit kinesthetic responses that show well-organized somatotopic arrangement, with the leg on the dorsolateral side, arm on the medioventral side, and face on the more medial side. Some Vim neurons have rhythmic bursting discharges synchronous with limb tremor. These electrophysiological findings allow us to achieve better surgical results.

Camptocormia is a rare and disabling movement disorder resulting in forward bending of the trunk. Camptocormia has many etiologies, although it is frequently observed patients with in Parkinson's disease and dystonia. Deep brain stimulation(DBS)of the globus pallidus internus(GPi)and subthalamic nucleus effectively treats camptocormia in Parkinson's disease and dystonia patients. Herein, we report a case of dystonic camptocormia induced by repetitive abdominal muscle exercise in which treatment was administered using bilateral GPi-DBS. A 54-year-old woman developed dystonic camptocormia at 53 years of age. Prior to the onset of symptoms, she regularly performed 200 abdominal muscle exercises per day. Oral medications, and botulinum toxin and lidocaine injections, were ineffective. Truncal anterior bending occurred while standing and walking. The patient underwent bilateral GPi-DBS, which instantly and dramatically improved her symptoms. The Burke-Fahn-Marsden dystonia rating scale subscore for the trunk before and after bilateral pallidotomy was 6 and 0, respectively. No perioperative adverse events were observed. Symptomatic relief persisted for 2 years. This case suggest that camptocormia can result from repeated abdominal muscle exercise, and that bilateral GPi-DBS may be a feasible and long-term efficacious procedure for dystonic camptocormia.

Six cases of dystonic tremor were treated with the Vercise TM deep brain stimulation(DBS)system, which has the multiple independent current control(MICC)technology. The mean preoperative score of Burke-Fahn-Marsden dystonia rating scale was 16.2±9.4, which was reduced to 6.1±4.6 at 5 months postoperatively. A 65-year-old male presented an intractable dystonic tremor of the jaw, neck, and shoulders due to tardive syndrome. He experienced the successful tremor relief after unipolar DBS in the globus pallidus internus(GPi)with Vercise TM but complained of dysarthria. Steering the current ventrally induced nausea without alleviating dysarthria, while steering the current dorsally alleviated dysarthria but a further dorsal current induced mandibular dyskinesia. The current steering with MICC enabled the simulation field in GPi with successful balance, maximizing tremor suppression, and minimizing the adverse effects. In a second case, 61-year-old male in whom cervical dystonia with rotatory tremor had been successfully treated with interleaving stimulation of GPi-DBS had needed to repeat the replacement of a non-rechargeable pulse generator in only 15-month interval. After the substitution of Vercise TM , the interleaving stimulation of 9.5mA in total was replaced by 8.5mA with the current steering of MICC, while the patient's symptomatic control was unchanged. The microlesion effects after lead implantation are unclear and therapeutic effects are often delayed in cases of dystonia;therefore, the submaximal stimulation intensities must be frequently applied in the early phase following the implantation of DBS. A fine current steering of Vercise TM DBS is very useful in both, the early and late phases of GPi-DBS for dystonic syndrome.

Deep brain stimulation (DBS) has been widely performed for various medically refractory movement disorders. For Parkinson disease (PD), target of DBS is subthalamic nucleus (STN) or globus pallidus internus (GPi). There are some evidences to demonstrate its effectiveness on motor function and QOL. DBS effectively improves levodopa-responsive motor symptoms, and significantly reduces dyskinesia and motor fluctuations. STN DBS particularly decreases the need for dopaminergic medication. A combination of medical treatment and DBS would provide longer relief of motor symptoms than medical treatment only. Currently new evidence supporting early introduction of DBS for better future outcome is published. DBS of Vim thalamus has been indicated for intractable tremor with various etiologies. Recently posterior subthalamic area (PSA) is introduced as an alternative target to Vim for tremor. GPi DBS is also effective treatment option for generalized dystonia.

A 71-year-old female was suffered from acute mountain sickness at an altitude of about 3,700 m. and became comatose. Although the patient recovered from the symptom after coming down from the mountain, family members and friends began to notice her personality changes in daily life. She became apathetic, uncommunicative, expressionless, less interested in hobbies and less sociable and was pointed it out by them. In neurological images, MRI revealed localized lesions at the globus pallidus, bilaterally. It was conjectured that pallidal lesions caused by hypobaric hypoxia at high elevation in the case induced neurobehavioral syndrome (globus pallidus syndrome) similar to the frontal lobe syndrome by way of the frontal-subcortical circuits. As, in recent years, the transportation to high ground has become relatively easy for the elderly, it is feared that the incidence of acute mountain sickness may increase. In acute mountain sickness, while neurological symptoms at the acute phase, such as headache, consciousness disturbances and ataxia, are emphasized, it is necessary, in examination of patients who recovered from acute symptoms, to recognize the presence of executive dysfunction as aftereffect, as seen in the present case.

During the last decade, it has become clear that deep brain stimulation (DBS) therapy provides a dramatic improvement in the symptoms of movement disorders. We have experienced DBS in 110 patients with various types of involuntary movements, and confirmed the benefits of stimulation of the thalamic nucleus ventralis intermedius (Vim), internal globus pallidus (GPi) and subthalamic nucleus (STN) in these patients. DBS therapy affords the best effect on tremor when the Vim is selected as the stimulation site. DBS therapy is also useful for controlling rigidity when the GPi or STN is stimulated. Improvements of bradykinesia and gait disturbance are often induced by DBS therapy involving the GPi or STN. Dopa-induced dyskinesia can be attenuated effectively by the direct and/or indirect effects of DBS therapy. DBS of the Vim also provides excellent control of post-stroke involuntary movements, including hemiballism and hemichoreoathetosis. Dystonia in young patients is controlled effectively by DBS of GPi. Ablative procedures for control of involuntary movement disorders, such as thalamotomy and pallidotomy, always carry a risk associated with creating additional lesions in an already damaged brain. In contrast, there is not such a risk in DBS therapy. This modality of therapy is an important option in treating involuntary movements.

We report a 48-year-old woman with dentatorubral-pallidoluysian atrophy (DRPLA). She is the only patient in her 15 family members in two generations. She developed cerebellar ataxia and epilepsy at age 43. On admission at 48, she showed mild dementia and choreic movement in her face and extremities as well as truncal and limb ataxia. Routine laboratory examinations were normal. The point mutations in the tRNALys gene of mitochondrial DNA specific for MERRF were not found. A cranial CT scan and MRI showed mild atrophy of the cerebellum and prominent atrophy in the pons, especially in the tegmentum. Although she was thought to have DRPLA from the clinical point of view, absence of family history made the diagnosis difficult. Her parents were healthy until their 80's and died of cerebrovascular diseases and her 5 siblings had no symptoms. Hereditary DRPLA is known as an autosomal dominant disorder, with a high rate of penetrance and low rate of new mutation. According to our recent findings of a CAG repeat expansion in the DRPLA gene, this patient was diagnosed as a sporadic DRPLA. Considering the wide varieties of clinical manifestations, it is essential to examine this gene abnormality for diagnosing sporadic DRPLA.

We report a patient with idiopathic hypoparathyroidism associated with unilateral calcification of the basal ganglia and contralateral choreic movements. A 66-year-old woman was admitted to our hospital because of involuntary movements of the left limbs. Two years before the present admission, she had operations for bilateral cataracts. Eight months before admission, she had an onset of severe carpal spasms and pain in both arms and legs. These symptoms improved after one month's rest in a hospital. About a month before admission, she noted progressive difficulty in using her left hand, followed by difficulty in walking due to the abnormal involuntary movement of the left lower limb. Two weeks before admission her carpal spasms appeared again, bilaterally. On admission, she was alert. The general physical examination was normal. Neurological examination revealed choreic movements in the left hand, arm, leg and neck, and grimacing of the left face. She also complained of the spasms and pain in her hands, dysarthria and shortness of the breath. Chvostek and Trousseau signs were positive. Laboratory examination revealed marked decrease in serum calcium level (2.57 mEq/ml) and increase in inorganic phosphorus level (6.40 mEq/ml). Serum level of parathyroid hormone was less than 10 pg/ml. Ellthworth-Howard test was positive, in that the infusion of parathyroid hormone (100 u) elicited a marked increment of the urinary excretions of phosphorus and cAMP. X-ray examination of the spine revealed ossification of the posterior longitudinal ligament in the cervical region. CT-scans of the brain revealed calcification in the region of right globus pallidus and putamen.(ABSTRACT TRUNCATED AT 250 WORDS)