Stereotactic Thalamotomy Research Articles

Hassler and Dieckmann's seminal paper on stereotactic thalamotomy for Gilles de la Tourette syndrome: Translation and critical reappraisal

Papers concerning the use of deep brain stimulation to the thalamus for relief of symptoms of Tourette syndrome have frequently cited a paper by Hassler and Dieckmann, published in 1970. We present a translation of this paper and discussion in English.

Successful treatment of tremor in Wilson's disease by thalamotomy: A case report

Little information is available on the surgical treatment of movement disorders in Wilson's disease. We report a successful outcome of left-sided stereotactic thalamotomy in a 30-year-old man with Wilson's disease, who had severe postural-kinetic tremor of both hands. The improvement was bilateral. Our case illustrates that stereotactic thalamotomy may be considered as an option in treating severe tremor in selected patients of Wilson's disease and merit further trials.

Stereotactic Ventrooral Thalamotomy for Task-specific Focal Hand Dystonia (Writer's or Musician's Cramp)

Stereotactic Ventrooral Thalamotomy for Task-specific Focal Hand Dystonia (Writer's or Musician's Cramp)

Tremor in multiple sclerosis

Tremor is estimated to occur in about 25 to 60 percent of patients with multiple sclerosis (MS). This symptom, which can be severely disabling and embarrassing for patients, is difficult to manage. Isoniazid in high doses, carbamazepine, propranolol and gluthetimide have been reported to provide some relief, but published evidence of effectiveness is very limited. Most trials were of small size and of short duration. Cannabinoids appear ineffective. Tremor reduction can be obtained with stereotactic thalamotomy or thalamic stimulation. However, the studies were small and information on long-term functional outcome is scarce. Physiotherapy, tremor reducing orthoses, and limb cooling can achieve some functional improvement. Tremor in MS remains a significant challenge and unmet need, requiring further basic and clinical research.

Functional MRI for immediate monitoring stereotactic thalamotomy in a patient with essential tremor

The effect of stereotactic thalamotomy was assessed with pre- and postoperative functional magnetic resonance imaging (fMRI) under motor stimulation. A patient with unilateral essential tremor (ET) of the left arm underwent stereotactically guided thalamotomy of the right ventral intermediate thalamic nucleus (VIM). FMRI was done directly before and after surgery on a 1.5-Tesla scanner. The stimulation paradigm was maintainance of the affected arm in an extended position and hand clenching being performed in a block design manner. Statistical analysis was done with Brain Voyager 2000. After thalamotomy the tremor diminished completely. As a difference between the pre- and postoperative fMRI, a significant activation was found in the VIM contralateral to the activation site, adjacent to the inferior olivary nucleus contralateral to the activation site and in the dorsal cingulum. In conclusion, fMRI can detect the functional effect of thalamotomy for tremor treatment. Direct postoperative fMRI provides a sufficient method for estimating the effect of thalamotomy immediately after intervention. The importance of the intermediate thalamic nucleus and the olivary nucleus in tremor generation is supported by our findings.

Parkinsonian Voice Acoustic Analysis in Real-Time after Stereotactic Thalamotomy

The voice acoustic structure in 7 male patients with Parkinson’s disease was analyzed 1 week before and 1 week after right-sided thalamotomy. The voice signal of the 3-digit number 306 was analyzed in real-time using a digital frequency analyzer. The average value of intensity level during the initial segment of the speech signal became higher after thalamotomy (75.04 vs. 59.24 dB). The voice fundamental frequency increased from 104 to 122 Hz. Before the operation, the energy focus of the speech signal was 73.19 vs. 76.87 dB postoperatively. The voice formants F1 and F2 shifted to the higher energy and frequency regions. The total sound pressure level of the pronounced 3-digit number 306 became two times higher after operation. The overall fluency of pronunciation was improved.

Hemiparkinsonism and levodopa‐induced dyskinesias after focal nigral lesion

We present a patient with tremor-dominant hemiparkinsonism after a focal lesion to the substantia nigra. An excellent response to levodopa was complicated by rapid development of motor fluctuations and disabling dyskinesias. Stereotactic thalamotomy resulted in a persistent extinction of parkinsonism and of dyskinesias along with stopping dopaminergic treatment.

History of Korean Stereotactic and Functional Neurosurgery

ALTHOUGH FUNCTIONAL SURGERY for movement disorders did not begin in Korea until after the introduction of the stereotactic apparatus in 1958, some surgeons had already begun operating on epileptic patients, psychiatric patients, and patients with pain disorders even before the Korean War broke out in 1950. The Korean War itself was a good opportunity for the army surgeons to learn Western neurosurgery, and many operations for pain were performed during this period. Stereotactic thalamotomy and pallidotomy for parkinsonian tremor began in the late 1950s, but it was not until the 1970s that Sang-sup Chung and Chang-rak Choi devoted themselves fully to this field and actively performed these functional operations. They later established the Korean Functional and Stereotactic Society in 1990. Following the lead of these pioneers, many young neurosurgeons began to enter the field in the 1980s to become full-time functional surgeons. Currently, the society has approximately 150 registered members interested in movement disorders, pain, epilepsy, and radiosurgery and working full-time or part-time in this field.

Gamma knife thalamotomy for movement disorders: evaluation of the thalamic lesion and clinical results

The authors studied the effects of gamma knife thalamotomy (GKT) on Parkinson disease-related tremor and essential tremor before and after reloading of radioactive cobalt. Based on experience in stereotactic thalamotomy aided by depth microrecording, the target was located at the lateral border of the thalamic ventralis intermedius nucleus (VIM). For more precise targeting, the percentage representation of the thalamic VIM in relation to the entire thalamic length is useful. The location of the target was determined on magnetic resonance (MR) imaging and computerized tomography scanning. A maximum dose of 130 Gy was delivered to the target by using a single isocenter with the 4-mm collimator. In more recent cases, a systematic follow-up examination was performed at 3, 6, 12, 18, and 24 months after GKT. Since 1993, the authors have treated 70 patients with PD. Throughout the series the same dosimetric technique has been used. The course after GKT was compared between the 25 cases with PD treated before reloading and the 35 cases treated after reloading. In the majority (80-85%) treated after reloading, tremor and rigidity were reduced around 6 months after GKT. In the cases treated before reloading this effect took approximately 1 year. The thalamic reaction on MR imaging showed the same two lesion types in both series: a restricted and a diffuse. After reloading the restricted lesion was more frequent and the lesion volume was smaller. The shorter delay in clinical improvement and smaller lesion size may be related to an increased radiation dose.

Gamma knife thalamotomy for movement disorders: evaluation of the thalamic lesion and clinical results

Object. The authors studied the effects of gamma knife thalamotomy (GKT) on Parkinson disease-related tremor and essential tremor before and after reloading of radioactive cobalt. Methods. Based on experience in stereotactic thalamotomy aided by depth microrecording, the target was located at the lateral border of the thalamic ventralis intermedius nucleus (VIM). For more precise targeting, the percentage representation of the thalamic VIM in relation to the entire thalamic length is useful. The location of the target was determined on magnetic resonance (MR) imaging and computerized tomography scanning. A maximum dose of 130 Gy was delivered to the target by using a single isocenter with the 4-mm collimator. In more recent cases, a systematic follow-up examination was performed at 3, 6, 12, 18, and 24 months after GKT. Since 1993, the authors have treated 70 patients with PD. Throughout the series the same dosimetric technique has been used. The course after GKT was compared between the 25 cases with PD treated before reloading and the 35 cases treated after reloading. In the majority (80–85%) treated after reloading, tremor and rigidity were reduced around 6 months after GKT. In the cases treated before reloading this effect took approximately 1 year. The thalamic reaction on MR imaging showed the same two lesion types in both series: a restricted and a diffuse. After reloading the restricted lesion was more frequent and the lesion volume was smaller. Conclusions. The shorter delay in clinical improvement and smaller lesion size may be related to an increased radiation dose.

Stereotactic Voa-Vop Complex Thalamotomy for Writer’s Cramp

Stereotactic Voa-Vop Complex Thalamotomy for Writer’s Cramp

Stereotactic Ventrooralis Thalamotomy for Task-Specific Focal Hand Dystonia (Writer’s Cramp)

Background: Writer’s cramp is a type of focal dystonia due to dysfunction of the pallido-thalamo-cortical circuit. The symptom is refractory to most conservative treatment, though botulinum toxin injection is generally used for symptomatic relief. As a surgical treatment of dystonia, we performed stereotactic nucleus ventrooralis (Vo) thalamotomy for dystonic cramp of the hand. Methods: Twelve patients (5 men, 3 women; age 26–40 years, mean 32.1 years) with medically intractable task-specific focal dystonia of the hand underwent Vo thalamotomy. The stereotactic target was chosen at the junction of the anterior and posterior Vo nuclei. Results: The mean duration of the symptom ranged from 3 to 6 years (mean 4.5 years.) All patients had complained of difficulty in writing. Seven patients were professionals, such as a comic artist, guitarist and barber, and, because of the dystonic symptoms occurring during their work, they had stopped pursuing their profession. All patients showed immediate postoperative disappearance of dystonic symptoms, and the effect was sustained during the follow-up period (3–33 months, mean 13.1 months), except in one case. Two patients showed partial recurrence of the symptom and underwent second thalamotomy 5 months after the initial surgery with satisfactory results. The score on the writer’s cramp rating scale decreased significantly (p < 0.001) after Vo thalamotomy. There were no permanent operative complications. There was no mortality or permanent morbidity. Conclusion: Although a longer follow-up is needed, stereotactic Vo thalamotomy is a useful and safe therapeutic option for writer’s cramp.

Essential Tremor: Diagnosis and Treatment

Essential tremor is a common movement disorder in adults that interferes with the performance of functional and social activities. Differentiation of essential tremor from other tremor syndromes is important in order to provide appropriate patient education and therapy. The mainstays of pharmacotherapy are propranolol and primidone; however, in selected patients, agents such as alcohol, benzodiazepines, botulinum toxin, and gabapentin may provide symptomatic benefits. Advances in surgical interventions, such as stereotactic thalamotomy and thalamic deep brain stimulation, offer patients an alternative treatment modality when pharmacotherapy is inadequate. A treatment algorithm is provided to guide clinicians in the management of patients with essential tremor.

Kinaesthetic neurons in thalamus of humans with and without tremor.

Increased afferent input may alter receptive field sizes, properties and somatotopographic representation in the cortex. Changes in the motor thalamus may also occur as a result of altered afferent input. Such plasticity has been implicated in both sensory and movement disorders. Using tremor as a model of augmented afferent input to kinaesthetic/deep neurons representing the shaking limbs, we studied the representation and properties of these neurons in human thalamus in patients with resting tremor (RestTr) from Parkinson's disease, patients with action- or posture-induced tremor (ActionTr), and patients without tremor (NoTr). Data were collected during stereotactic thalamotomy or insertion of deep brain stimulators for relief of pain or movement disorder. Using microelectrode recording, 58 kinaesthetic neurons responding to wrist and/or elbow movement were studied by mapping the receptive field, carefully isolating each joint during testing. There were no significant differences in the proportions of single and multijoint responsive neurons in the different patient groups (RestTr, ActionTr and NoTr). The borders between tactile-cutaneous, deep-kinaesthetic and voluntary cell representations in the thalamus were mapped in 74 patients and compared between the different tremor groups. A significant difference in kinaesthetic representation was found: both the RestTr and ActionTr groups had a significantly greater kinaesthetic representation than the NoTr patients. There was an expansion of kinaesthetic representation in patients with chronic increased afferent drive from tremor, without alteration in RF size. No decrease in tactile representation was found, suggesting that the increase in kinaesthetic representation does not occur at the expense of tactile representation. These data suggest that plasticity can occur at the thalamic level in humans and may contribute to the pathogenesis of tremor.

Impact of Posterior GPi Pallidotomy on Leg Tremor in Parkinson’s Disease

Although stereotactic thalamotomy is the mainstay in the surgical treatment of tremor in patients with Parkinson’s disease (PD), this surgery is not favored and is even a matter of potential concern in the treatment of leg tremor since it carries a significant risk of injury to the internal capsule. In this study we have carried out a quantitative assessment of leg tremor alleviation in 12 patients with PD after MRI-/microelectrode-guided stereotactic ablation of the posterior part of the globus pallidus internus (GPi). The results showed that posterior GPi pallidotomy combined with drug therapy is a satisfactorily effective therapeutic strategy to treat parkinsonian leg tremor.

Cytotoxicity of ventricular cerebrospinal fluid from Parkinson patients: Correlation with clinical profiles and neurochemistry

Other investigators have reported that the cerebrospinal fluid (CSF) from patients with Parkinson's disease (PD) might contain endogenous dystrophic factors. Using CSF samples drawn from individual PD patients during surgery, we investigated the toxic effect of ventricular CSF (vCSF) on the growth of PC12 cells and the correlation between the clinical profiles of the patients and CSF neurochemistry. Ventricular CSF samples from 28 patients with PD or essential tremor (ET) were collected during ventriculography for stereotactic pallidotomy or thalamotomy. PC12 cells were incubated with 20% vCSF from both clinical groups for up to 72 h. Microdialysis was used to analyze four neurochemical parameters (glucose, lactate, pyruvate, and glutamate) in each vCSF sample. We observed that vCSF drawn from PD patients exerted nonspecific growth inhibition on PC12 cells in a time-dependent manner. The growth inhibitory action of PD–vCSF decreased significantly after heat treatment. Microdialysis demonstrated no statistical differences between PD and ET samples among the four parameters studied. In addition, PC12 cell survival after 72 h incubation with PD-vCSF correlated with no neurochemical parameter or individual clinical profile (age, onset age, duration of disease, Hoehn & Yahr stage, disease progression rate), except for a slight correlation between vCSF and disease progression rate in heat treated samples from female patients. One or more endogenous cytotoxic factors in PD-vCSF inhibit PC12 cell growth. This factor or factors are partially sensitive to heat which suggests proteins or peptides as possible agents. The cytotoxic effect of PD-vCSF did not directly correlate with any clinical profiles studied or energy metabolism of PD brain.

&lt;b&gt;Indication of various kinds of surgical treatment &lt;/b&gt;&lt;b&gt;for central (thalamic) pain &lt;/b&gt;

We studied the effect and the indication of various kinds of surgical treatment for central (thalamic) pain in 10 cases. In 3 cases with localized pain, epidural spinal cord stimulation was effective. In 7 cases with diffuse pain (hemibody), stereotactic Vim-Vcpc thalamotomy was performed with the aid of depth microrecording. In 4 of these cases in which pain relief was obtained, we could find responses to peripheral natural stimulation on the sensory thalamus during the operation. Preoperative PET study also revealed an increase of rCBF on the sensory cortex ipsilateral to the thalamic CVD lesion during contralateral thumb brushing. On the other hand, in the 3 cases in which we failed to obtain pain relief, we frequently encountered irregular burst discharges on the thalamus. Gamma thalamotomy was added after the conventional thalamotomy in these 3 cases. Though transient pain relief was obtained, pain recurred thereafter. Precentral electrical cortical stimulation was also carried out in 3 recurrent cases, resulting in the failure of pain relief. In one of these cases, internal capsular (posterior limb) stimulation was performed, obtaining encouraging result. In cases of localized thalamic pain, epidural spinal cord stimulation proved to be an effective treatment. Thalamic surgery achieved pain relief in those cases with diffuse type pain, limited to preserving sensory function on the sensory thalamocortical system. Precentral electrical cortical stimulation, internal capsular (posterior limb) stimulation or Gamma thalamotomy may be an alternative treatment for central (thalamic) pain.

Thalamic lesions produced by gamma thalamotomy for movement disorders

Object. The treatment of Parkinson disease and other kinds of involuntary movement by gamma knife radiosurgery (GKS) is presented. This is an extension of previous work. The clinical course and thalamic lesions were the main factors examined. Methods. Seventeen new cases were added to the previously reported 36 cases. The course and results for the whole series of 53 patients were examined. Treatment was undertaken using a single 4-mm collimator shot to deliver 130 Gy to the target. The target was determined in the previously treated patients by using classic methods involved in conventional stereotactic thalamotomy with microrecording. More recently, target localization has been performed by relating the target point to the total length of the thalamus. Points may then be defined as percentages of that length measured from the anterior pole. Targets can then be determined in relationship to the appropriate percentage. Thirty-five patients have been followed for more than 2 years and the longest follow up was 8 years. Two kinds of thalamic lesion were seen after GKS. Volumetric analysis on MR imaging revealed that the larger lesion was 400 to 500 mm3 at the beginning and gradually decreased in size. The smaller lesion occupied approximately 200 mm3 and also shrank over several months. Eighty percent of the treated cases showed good results and no significant complications, with the tremor subsiding at 1 year (Type 1). Several cases deviated from this standard course in four different ways (Types 2–5). If tremor persisted, conventional stereotactic thalamotomy with microrecording was performed. During such operations, normal neuronal activity was recorded from the region adjacent to the GKS thalamotomy target. This was the region showing a high signal on MR imaging. The activity patterns included the rhythmical grouped discharge of tremor rhythm. Conclusions. Gamma thalamotomy for functional disorders is still under development, but because the results with careful target planning are satisfactory, there are grounds for increasing optimism.

RETRACTED: Proton MR spectroscopic changes in Parkinson's diseases after thalamotomy

To investigate whether there are significant changes in regional brain metabolism in patients with Parkinson's disease before and after thalamotomy using proton magnetic resonance spectroscopy (1H MRS). Fifteen patients underwent 15 stereotactic thalamotomies for control of medically refractory parkinsonian tremor. Single-voxel 1H MRS was carried out on a 1.5 T unit using stimulated-echo acquisition mode (STEAM) sequence (TR/TM/TE, 2000/14/20 ms). Spectra were obtained from substantia nigra, thalamus and putamen areas with volumes of interests (7-8 ml) in patients before and after the surgery. Metabolite ratios of NAA/Cho, NAA/Cr and Cho/Cr were calculated from relative peak area measurements. We evaluated alterations of metabolite ratios in brain metabolism in Parkinson's disease patients with clinical outcome following thalamotomy. NAA/Cho ratios showed generally low levels in substantia nigra and thalamus in Parkinson's disease patients with clinical improvement following thalamotomy. In 80% (12/15) patients, decreased NAA/Cho ratios were observed from the selected voxels in substantia nigra after thalamic surgery (P<0.05). The ratios were also significantly decreased in thalamus in 67% (10/15) patients with clinical improvement (P<0.05). Our results suggest that NAA/Cho ratio may be a valuable criterion for evaluation of Parkinson's disease patients with the clinical improvement following surgery. 1H MRS may be a useful utility for the aid in better understanding the pathophysiologic process in Parkinson's disease patients on the basis of the variation of NAA/Cho ratio.

Optimal location of thalamotomy lesions for tremor associated with Parkinson disease: a probabilistic analysis based on postoperative magnetic resonance imaging and an integrated digital atlas.

Renewed interest in stereotactic neurosurgery for movement disorders has led to numerous reports of clinical outcomes associated with different treatment strategies. Nevertheless, there is a paucity of autopsy and imaging data that can be used to describe the optimal size and location of lesions or the location of implantable stimulators. In this study the authors correlated the clinical efficacy of stereotactic thalamotomy for tremor with precise anatomical localization by using postoperative magnetic resonance (MR) imaging and an integrated deformable digital atlas of subcortical structures. Thirty-one lesions were created by stereotactic thalamotomy in 25 patients with tremor-dominant Parkinson disease. Lesion volume and configuration were evaluated by reviewing early postoperative MR images and were correlated with excellent, good, or fair tremor outcome categories. To allow valid comparisons of configurations of lesions with respect to cytoarchitectonic thalamic boundaries, the MR image obtained in each patient was nonlinearly deformed into a standardized MR imaging space, which included an integrated atlas of the basal ganglia and thalamus. The volume and precise location of lesions associated with different clinical outcomes were compared using nonparametric statistical methods. Probabilistic maps of lesions in each tremor outcome category were generated and compared. Statistically significant differences in lesion location between excellent and good. and excellent and fair outcome categories were demonstrated. On average, lesions associated with excellent outcomes involved thalamic areas located more posteriorly than sites affected by lesions in the other two outcome groups. Subtraction analysis revealed that lesions correlated with excellent outcomes necessarily involved the interface of the nucleus ventralis intermedius (Vim; also known as the ventral lateral posterior nucleus [VLp]) and the nucleus ventrocaudalis (Vc; also known as the ventral posterior [VP] nucleus). Differences in lesion volume among outcome groups did not achieve statistical significance. Anatomical evaluation of lesions within a standardized MR image-atlas integrated reference space is a useful method for determining optimal lesion localization. The results of an analysis of probabilistic maps indicates that optimal relief of tremor is associated with lesions involving the Vim (VLp) and the anterior Vc (VP).