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Background/aims: The objective of the present study was the evaluation of the effectiveness of robotic microradiosurgery of skull base meningiomas using Leksell Gamma Knife model C with an automatic positioning system., Methods: The results of the management of 66 tumors were analyzed retrospectively. Their volume varied from 0.3 to 50.6 cm³ (mean = 6.6). The treatment plan was based on the use of multiple small isocenters compactly positioned within the border of the lesion with resultant improved homogeneity of high-dose distribution, increased average dose within the target and sharp dose fall outside the treated volume. The marginal dose varied from 10 to 14 Gy (mean = 12). The length of follow-up ranged from 26 to 80 months (mean = 46)., Results: The overall tumor growth control was 99%. Reduction of the mass volume was marked in 54 patients (82%), and in 15 of them it constituted ≥ 50%. In other 11 cases (17%) stabilization of the lesion growth was noted. The shrinkage rate significantly correlated with amount of radiation energy delivered per tumor volume, designated as unit energy (p = 0.007). One meningioma (1%) regrew 3.5 years after radiosurgery. The treatment-related morbidity was limited to transient abducens nerve palsy in 1 patient (1%)., Conclusion: Application of the concept of Gamma Knife robotic microradiosurgery for the management of skull base meningiomas may change the paradigm of their treatment from stabilization of growth to reduction of the volume of the neoplasm. The tumor shrinkage rate may depend on the amount of radiation energy delivered per lesion volume (unit energy)., (Copyright © 2010 S. Karger AG, Basel.)

Rationale: Two or three decades ago, cancer pain was treated by surgical/chemical hypophysectomy. In one report, the control of central pain (thalamic pain syndrome) was also approached with chemical hypophysectomy. Although in most of the patients these treatments resulted in a decrease in severe pain, concomitantly severe adverse effects (panhypopituitarism, diabetes insipidus and visual dysfunction) occurred in most patients. This historical evidence prompted us to perform Gamma Knife surgery (GKS) for this kind of intractable severe pain using a high irradiation dose to the pituitary stalk/gland. In the majority of patients, marked pain relief was achieved, surprisingly without any of the complications mentioned above., Materials and Methods: A prospective multicenter study was conducted to evaluate the efficacy and safety in patients treated in Prague, Hong Kong and Tokyo. Indications of this treatment were: (1) failure of other effective treatment approaches prior to GKS, (2) good general patient condition (Karnofsky performance status >40%), (3) response to morphine for pain control (cancer pain), and (4) no previous radiotherapy of brain metastases (GKS/conventional radiotherapy). Eight patients with severe cancer pain due to bone metastasis and 12 patients with post-stroke thalamic pain syndrome were treated with GKS. The target was the border between the pituitary stalk and gland. Maximum dose was 160 Gy for cancer pain and 140 Gy for central pain. Follow-up included 6 patients (>1 month) with cancer pain and 8 patients (> 6 months) with thalamic pain syndrome., Results: All patients (6/6) with cancer pain experienced significant pain reduction, and 87.5% (7/8) of the patients with thalamic pain had initially significant pain reduction. In some patients, pain reduction was delayed for several hours. Pain relief was noted within 7 days (median 2 days). No recurrence was observed in the patients with cancer pain. However, in 71.4% (5/7) of the patients with thalamic pain syndrome, disease recurred during the 6-month follow-up. Up to now, other complications have not been observed., Conclusion: Our clinical study protocol is only preliminary. Further clinical results on the management of thalamic pain are required to develop this treatment protocol. However, efficacy and safety have been shown in all our cases. In our opinion, this treatment has a potential to control severe pain, and GKS will play an important role in the management of intractable pain., (Copyright 2003 S. Karger AG, Basel)

Information-guided stereotaxis, assisted by visualization of medical information, will become the next generation of neurosurgical systems. We performed 76 open MRI surgeries at Tokyo Women's Medical University between March 3, 2000 and April 12, 2001. Of them, comparisons of pre- and post-operative MR images for malignant gliomas in 21 cases revealed an average resection rate of 90.3% (the maximum 100%, the minimum 55%). In this article we describe real time updated navigation, augmented reality navigation, three-dimensional navigation, chemical navigation, information-guided navigation system (High definition visual Computer Aided Surgery System: HivisCAS), and open MRI-guided surgery that we are developing., (Copyright 2002 S. Karger AG, Basel)

Ninety-two patients with pituitary adenomas have been treated during the last 5 years. Sixty-three of these patients had more than 6 months follow-up, and they form the basis of this report. Eighteen had non-functioning adenomas (NFA), and 36 had functioning adenomas (FA). The mean marginal dose was 22.5 Gy (NFA 19.5 Gy, FA 23.9 Gy). Control of tumor growth was achieved in 92%. A significant decrease of excessive hormone production was seen in 75.6%, and the endocrinopathy normalization rate was 26.7%. Post-radiosurgical complications were seen in 4.7%.

Gamma Knife radiosurgery is an effective treatment for meningiomas. However, it may be difficult to deliver what is currently considered an optimal dose, especially if the tumor is large or adjacent to critical structures. Eleven cases are presented with a follow-up of more than 12 months where the margin dose did not exceed 10 Gy. The mean age was 48.8 years. The mean follow-up period was 35.7 months (range 21 to 57 months). The mean volume of the tumors was 9.4 cm3 (range 1.6 to 28.9 cm3). The margin dose was less than 10 Gy in all 11 cases, due to a large volume in two cases. Four tumors were close to the visual pathways. Five tumors were close to the brain stem. Imaging follow-up showed that four tumors had shrunk after radiosurgery. The remaining seven cases remained unchanged. There was no tumor growth after radiosurgery. A transient oculomotor palsy was observed in two cases after radiosurgery. It is suggested that Gamma Knife radiosurgery using lower dosage than usual is one of the options for the treatment of meningioma.

We report a patient with intractable left facial pain and severe hyperkinesia of the left arm who was successfully treated with deep brain stimulation. The stimulation lead was positioned to pierce both the sensory relay nucleus and the nucleus ventrointermedius of the thalamus in a single stereotactic trajectory through an occipital burr hole.

Clinical experience with the use of pergolide is presented in 55 patients with Parkinson's disease. Fifty to 900 micrograms/day (mean 242.73, SD 217.51) of pergolide and 0.64-17.05 micrograms/kg/day (mean 4.58, SD 4.25) pergolide was given together with L-carbidopa to 29 males and 26 females for a period of up to 2 years 7 months. Low-dose pergolide together with L-carbidopa is effective in the treatment of parkinsonism without side effects, even in advanced stages of the disease. No patients required surgical treatment such as pallidotomy or deep brain stimulation recommended by other investigators. We emphasize that parkinsonism can be sufficiently treated with pergolide and L-dopa and that surgical treatment should be minimized unless there is no alternative.

Objective: We have developed an overlaid three-dimensional image (Volumegraph)-guided navigation system that allows navigation during operative procedures. The three-dimensional image is superimposed on the patient's head and body via a semi-transparent mirror. The Volumegraph can display three-dimensional images in the air by a light beam which is based on CT/MRI., Method: The system consists of a Volumegraph (thin plate of three-dimensional recorded medium), a Volumegraphscope and an original designed triangular-shaped marker system for registration. The three-dimensional data obtained from CT and MRI before the operation were processed by a computer. Such image data are applied for preoperative investigation to recognize the three-dimensional structure of organs and tumor. These reconstructed three-dimensional images were superimposed and registered at the patient's head according to a fiducial marker (registration). Then the operator can operate with this three-dimensional-image-guided navigation system., Results: Based on clinical application in 7 cases, the system was found to be advantageous because the surgical procedures could be navigated easily by augmented reality in the surgical field. Invisible parts of the surgical field were supplemented with the overlaid three-dimensional images (Volumegraph) as if it were the virtual operative field. At another time, spatial positioning and overlaid visualization by the Volumegraph was useful for identifying anatomical structures and functional location in the image., Conclusion: This preliminary study of overlaid three-dimensional-image-guided navigation demonstrated its clinical usefulness. The application of augmented reality in the surgical field makes it possible to do a neurosurgical intervention easily and accurately.

We report three patients who underwent Gamma Knife radiosurgery for benign tumors (meningioma, neurinoma and hemangioblastoma), in whom an 'unchanged tumor volume' demonstrated by postirradiation follow-up neuroimaging could be regarded as a successful treatment results, as compared with preradiosurgery tumor growth. It is our view that unless significant tumor growth has been observed before radiosurgery, 'unchanged in size' after radiosurgery cannot be regarded as a successful treatment result. Because relatively few hemangioblastoma patients have been treated radiosurgically, this report emphasizes the course of one case with hemangioblastoma.

We review 48 cases of meningioma treated with Gamma Knife radiosurgery. The mean marginal dose was 15 Gy and the mean follow-up was 12 months. Follow-up computed tomography and magnetic resonance imaging showed tumor shrinkage in 19 cases, central necrosis in 1 case, loss of contrast enhancement in 1 case, and no change in 27 cases. We noted 4 cases of radiation-induced edema in supratentorial meningiomas.

Baclofen, an agonist of the gamma-aminobutyric acid (GABA) receptor, has antinociceptive effects, and its intrathecal administration reduces allodynic responses in animal models of neurogenic central pain. Such experimental studies lead to the hypothesis that neurogenic pain may be induced in part by functional abnormalities in spinal GABAergic systems. However, whether a GABAergic system is actually involved in human central pain is unknown. The authors investigated the effect of an intrathecal bolus injection of baclofen in 14 patients with central pain due to a stroke or spinal cord injury. Nine reported substantial pain relief they had never experienced previously. The effect appeared 1-2 h after the injection and persisted for 10-24 h. Allodynia and hyperalgesia, if present, were relieved as well. Pinprick and light touch sensations did not change in nonaffected regions. The results indicate that dysfunction of spinal GABAergic systems plays a role in the clinical expression of central pain. In clinical situations, continuous intrathecal infusion of baclofen seems feasible for relief of central pain.

A new simulation system utilizing digital images (CT/MRI/SPECT) and an ultrasound/laser navigation system has been developed for image-guided surgery. Preoperative CT/MRI imaging does not always indicate the actual location of the lesion during intracranial operation, because the lesion may be displaced or distorted by operative procedures or CSF flowout. The authors developed an image integration system including an intraoperative ultrasonogram, which provides accurate information not only on the location of the deep-seated lesions but also surrounding anatomical structures during operation. The rationale of the system is to coordinate the three-dimensional axes of each image with the aid of a stereotactic subframe. Our simulation system has two ways. One simulation system works on a SUN workstation. At the preoperative simulation study: the entry point on the brain surface and the access route to the lesion are decided on from the three-dimensional CT/MRI images on the computer display. Then the configuration of the lesion from the operative view is displayed as an expected ultrasound image by reconstructing the CT and/or SPECT image. Another simulation system (HyperCAS) works on the HyperCard of a MacIntosh. The target point, the entry point and the trajectory are decided on and the three-dimensional location of these points is measured from serial CT images on the LCD display. At the time of operation, stereotactic craniotomy is performed using the laser navigator. The extent of the lesion at every depth in the surgical process is predicted from these images, and the access route to the lesion is easily corrected with the intraoperative ultrasound navigator.(ABSTRACT TRUNCATED AT 250 WORDS)

The robot technology was introduced into a new stereotactic neurosurgery system for applications to biopsy, blind surgery, and functional neurosurgery. The authors have developed a newly designed prototype microsurgical robot, designed to allow a biopsy needle to reach the target such as a cerebral tumor within a brain automatically on the basis of the X, Y, and Z coordinates obtained by CT scanner. This robot is so small that it can be driven in a CT scanner gantry. It consists mainly of the link mechanism and the insertion mechanism. We constructed the link mechanism and investigated its working space.