Gamma knife thalamotomy for Parkinson disease and essential tremor: a prospective multicenter study.

Background: No prospective study of gamma knife thalamotomy for intractable tremor has previously been reported.

Objective: To clarify the safety and optimally effective conditions for performing unilateral gamma knife (GK) thalamotomy for tremors of Parkinson disease (PD) and essential tremor (ET), a systematic postirradiation 24-month follow-up study was conducted at 6 institutions. We present the results of this multicenter collaborative trial.

Treatment of functional disorders with gamma knife thalamotomy.

Gamma knife (GK) thalamotomy for functional disorders, primarily Parkinson disease and central pain, are described herein. The goal was to extend our present indications for selective thalamotomy. Our target for tremor surgery is about 45% of the thalamic length.

From selective thalamotomy with microrecording to gamma thalamotomy for movement disorders.

A theoretical and practical process from microrecording-guided thalamotomy to gamma knife thalamotomy was briefly reviewed. Based on our own experiences of selective thalamotomy with microrecording, we are trying to apply gamma knife to the treatment of movement disorders. An important technical problem is how to determine the exact thalamic target.

Neurophysiological evaluation of the optimum target in gamma thalamotomy: indirect evidence.

Gamma thalamotomy has been useful for the treatment of Parkinson's disease and other movement disorders, but it has disadvantages, such as a delayed clinical effect after irradiation and the inaccuracy of targeting because depth recording is not available. Therefore, we sought to determine the optimum target in gamma thalamotomy based on the results of conventional selective thalamotomy with reference to the AC-PC line. To obtain indirect support for the appropriateness of the optimum target, we performed depth recording around the region of the estimated optimum target based on the results of conventional thalamotomy.

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.

Forty years with Professor Narabayashi.

Professor Hirotaro Narabayashi (1922-2001) was the founder of stereotactic neurosurgery in Japan and one of the early great world pioneers in this field. He constructed his first stereotactic apparatus in 1949 and performed his first pallidotomy in 1951, unaware of the similar work of others outside postwar Japan. His neurological clinic, which opened in Tokyo in 1957, became an international center for stereotaxy for more than 40 years.

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.

Lesioning the thalamus for dyskinesia.

Recent advances on understanding the pallidothalamic relation lead us to perform Vim-Vo thalamotomy (combined thalamic lesion in ventralis intermedius nucleus and ventralis oralis nucleus) for cases with dyskinesia. In our recent series of thalamotomies, there are 12 cases of dyskinesia caused by various etiologies. Therefore the clinical manifestation of the involuntary movement was different in each case, including, more or less, some elements of irregular involuntary hyperkinetic movement.

Use of selective thalamotomy for various kinds of movement disorder, based on basic studies.

Methods of selective thalamotomy with microrecording for several kinds of movement disorder are described. Precise thalamotomy (Vim, VO or Vim+VO) depends on the understanding of the functional organization of the human thalamus on the one hand, and the patient's specific feature of movement disorders on the other. To realize selective thalamotomy, microrecording and a computerized planning system are essential.

The idea of stereotaxy toward minimally invasive neurosurgery.

The idea of stereotaxy in modern neurosurgery is reviewed. Stereotactic surgery has been one of the particular neurosurgical techniques mainly used for functional disorders. Nowadays, it is widely used in the field of general neurosurgery owing to the rapid development of computer-assisted 3D brain images.

Evaluation of gamma thalamotomy for parkinsonian and other tremors: survival of neurons adjacent to the thalamic lesion after gamma thalamotomy.

Object: The effects of gamma thalamotomy for parkinsonian and other kinds of tremor were evaluated.

Methods: Thirty-six thalamotomies were performed in 31 patients by using a 4-mm collimator. The maximum dose was 150 Gy in the initial six cases, which was reduced to 130 Gy thereafter.

[Prospect of neurosurgical approach to Parkinson's disease in the 21st century].

After a brief review of the past and present status of stereotactic surgery, prospect of neurosurgical approach to Parkinson's disease in the 21st century was considered. The stereotactic surgery has progressed markedly in its technical and theoretical aspects due to the rapid development of the basic neuroscience and computerized imaging technique. Although there are some points to be clarified and estimated in the future, these new tendencies will stand to the next century, and further progress will be achieved if it contains some truth in the light of the modern neuroscience.