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. METHODS: In total, 72 patients (PD characterized by tremor, n = 59; ET, n = 13) were registered at 6 Japanese institutions. Following our selective thalamotomy procedure, the lateral part of the ventralis intermedius nucleus, 45% of the thalamic length from the anterior tip, was selected as the GK isocenter. A single 130-Gy shot was applied using a 4-mm collimator. Evaluation included neurological examination, magnetic resonance imaging and/or computerized tomography, the unified Parkinson's disease rating scale (UPDRS), electromyography, medication change, and video observations. RESULTS: Final clinical effects were favorable. Of 53 patients who completed 24 months of follow-up, 43 were evaluated as having excellent or good results (81.1%). UPDRS scores showed tremor improvement (parts II and III). Thalamic lesion size fluctuated but converged to either an almost spherical shape (65.6%), a sphere with streaking (23.4%), or an extended high-signal zone (10.9%). No permanent clinical complications were observed. CONCLUSION: GK thalamotomy is an alternative treatment for intractable tremors of PD as well as for ET. Less invasive intervention may be beneficial to patients.

Primary Ewing's sarcoma of the orbit: case report.

A 22-year-old man presented with tenderness and swelling of the left lateral part of the orbit. Computed tomography revealed a left intraorbital mass measuring 3 cm x 3 cm involving the left lateral wall of the orbit and the greater wing of the left sphenoid bone. Magnetic resonance imaging revealed that the intraorbital mass was extraneuroaxial. During surgery, the tumor was seen to arise from the lateral wall of the orbit and infiltrate into the left temporal muscle. Following the surgery, the patient was administered radiation therapy for the whole cranium and chemotherapy for the residual tumors. However, the tumor recurred, and the patient died about 2 years following the first surgery because the tumor had metastasized to the lung. On light microscopy, the tumor cells were closely packed with uniform, small, and round cells. Immunohistochemical studies showed that the tumor cell membrane stained positive for MIC2. Furthermore, the MIB-1 labeling index was 36.2%. On electron microscopy, small quantities of cytoplasm containing glycogen accumulations without neurosecretory granules and neurofilaments were observed. Based on these results, the tumor was diagnosed to be primary Ewing's sarcoma. Primary orbital Ewing's sarcoma of the skull has been considered to be extremely rare, and a review of the literature was performed.

Ultrastructural and immunohistochemical study of an adult case of chordoid meningioma.

A 64-year-old male patient presented with generalized convulsions. Magnetic resonance imaging revealed a large meningeal tumor with some cysts in the right frontal region. Surgical resections were performed three times, and local radiation therapy was administered twice over a period of 8 years for the treatment of tumor recurrences. The tumor tended to recur in spite of the surgical and radiation therapies. The tumor was diagnosed as a chordoid meningioma, and the second surgical specimen showed increasing nuclear atypia and mitoses in tumor cells. An immunohistochemical study revealed the tumor cells were positive for vimentin, S-100 protein, and cytokeratin AE1/AE3. An electron microscopic study revealed intracytoplasmic vacuolar spaces, loosely connected interdigitating cell processes with intermediate junctions, and extracellular spaces which contained fluffy granular intercellular substances. The tumor cell surfaces displayed pseudopodia which extended into the intercellular spaces and the tumor cells had moderate quantities of cytoplasm containing abundant mitochondria and glycogen granules. According to the ultrastructural features in the past reports of chordoid meningiomas, these meningiomas are suspected to have a mixture of the characteristic ultrastructural features of meningothelial meningiomas and chordoid sarcomas.

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. Thus, this principle was applied to deciding the GK thalamotomy target. In most of our cases, the protocol was 130 Gy, delivered in one shot with a 4-mm collimator. The time courses of thalamic lesion changes and clinical improvement after irradiation were assessed. Thus, despite thalamic reaction changes being variable, we achieved a clinical success rate of approximately 80% with negligible complications.

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. At first we refer to the posterior commissure and coordinate of the standard atlas for approximately determining the lateral part of the ventral intermediate nucleus. Then the point is further corrected by anatomical landmark (45% of the thalamic length) to compensate the individual difference. A final lesion is made by gamma knife using a 4-mm collimator, 130 Gy in 1 shot. The average delay of clinical improvement is about 6 months after irradiation. Thus far the results are satisfactory, being 80-85% successful without any noticeable complications. Only 3 days of hospitalization with minimal invasion could be a big advantage for the patient. Further technical progress may improve the clinical results in the future.

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. Four patients with tremor caused by Parkinson's disease or essential tremor were used as subjects after they gave their fully informed consent. The targets were determined as points 6-8 mm anterior to the posterior commissure, 4-6 mm dorsal to the level of the intercommissural line, and 15-17 mm lateral from the midline. Rhythmic discharge time-locked to tremor and/or kinesthetic neurons were found within the expected target area in all patients. Finally, in all cases, the tremor was abolished without complications after coagulative lesions were made with dual coagulation needles to cover the supposed Vim zone according to the depth recording. We considered that the target point determined in the same way as in gamma thalamotomy is suitable from an anatomophysiological perspective.

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.

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. This article describes his early career, with personal anecdotes and reminiscences from his interesting life.

Barbarian medicine in feudal Japan.

THE FIRST EUROPEANS to discover Japan were Portuguese traders who arrived in 1542. Fifteen years later, the Portuguese Jesuit priest and surgeon Luis De Almeida (1525-1583) founded the first Western hospital in Japan, for the care of lepers, syphilitics, and orphans. Because the hospital had a negative influence on the spread of Christianity, the Jesuits closed it in 1586. During the Tokugawa Shogunate (1600-1868), when Japan was secluded from the rest of the world, the only foreign physicians allowed to enter Japan were those employed by the Dutch factory at Dejima in Nagasaki. Only four of those physicians left behind seeds for the foundation of Western medicine in Japan, namely Caspar Schambergen, who founded a Japanese school of surgery in 1650; Engelbert Kämpfer, who visited Japan in 1691 to 1692; Carl Peter Thunberg, who botanically explored Japan in 1775 to 1776; and Philipp Franz Balthasar von Siebold, who practiced medicine in Nagasaki in 1823 to 1829 and 1859 to 1861. On the whole, Western medicine and surgery never established a real foothold in Japan until the fall of the shogunate and the restoration of the emperor in 1868.

Hemorrhage risks and obliteration rates of arteriovenous malformations after gamma knife radiosurgery.

OBJECT: The purpose of this study was to analyze the risk of hemorrhage and the obliteration rate after treatment of patients with arteriovenous malformations (AVMs). METHODS: Between 1991 and 1995, 115 patients were treated using gamma knife radiosurgery (GKS). Surgical planning was based on angiograms and three-dimensional images. The angiographic features of the AVMs and the risk factors for hemorrhage were then evaluated. Hemorrhages occurred in eight patients (7%) 7 to 42 months after GKS. Based on AVM morphology, the rates of hemorrhage were five (7.6%) of 66 for AVMs with a single draining vein, seven (14%) of 66 for AVMs with deep drainage, four (26.7%) of 15 for AVMs with a varix, four (28.6%) of 14 for AVMs with venous obstruction, eight (17.0%) of 47 for high-flow (shunt- and mixed-type) AVMs, and five (35.7%) of 14 for large AVMs with a volume of more than 10 cm3. No hemorrhages were observed in association with low-flow (moyamoya-type) AVMs in this series. Total AVM obliteration was achieved in 81.3% of 80 patients who underwent angiography. The obliteration rate was 91.3% for moyamoyatype AVMs and 67.6% for shunt- and mixed-type AVMs. Early obliteration within 12 months was achieved in 63% of the moyamoya-type AVMs. CONCLUSIONS: Moyamoya-type AVMs seem to be at risk for post-GKS hemorrhage. Intravascular embolization should be considered prior to GKS for mixed- and shunt-type AVMs in an attempt to reduce the hemodynamic stress and thereby decrease the risk of hemorrhage.

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.