Long-Term Results of Gamma Knife Radiosurgery for Trigeminal Neuralgia.

OBJECTIVE: Although the short- to medium-term efficacy of Gamma Knife therapy for drug-resistant essential trigeminal neuralgia has been reported, long-term evaluations are limited. We evaluated patient data obtained at least 10 years post-treatment and examined the significance of this treatment using new end points. METHODS: Among 249 consecutive patients with essential trigeminal neuralgia who were treated with Gamma Knife radiosurgery (retrogasserian target/4-mm single isocenter/90 Gy at 100%) at our institution between January 2003 and October 2011, 103 patients who were followed up for at least 10 years (mean, 174 [120-219] months) after treatment and whose data were amenable to accurate evaluation, were included in this retrospective study. Herein, we used the Barrow Neurological Institute (BNI) pain intensity scale as a clinical evaluation method for pain and the BNI numbness scale to evaluate complications (namely facial dysesthesia). RESULTS: The initial and final follow-up pain attack cessation (BNI pain intensity score I-IIIa) rate was 82.5% (85 of 103) and 58.2% (60 of 103), respectively. Furthermore, sensory impairment (BNI numbness score ≥ II) at the last follow-up was observed in 24.3% (25 of 103) of the cases, while very bothersome status (BNI numbness score IV) was observed in 2.9% of the cases. CONCLUSIONS: Gamma Knife radiosurgery for essential trigeminal neuralgia showed good therapeutic effects during long-term follow-up. Serious complications of significant concern in the short- to mid-term follow-up, resolved spontaneously. Therefore, the indications for treatment should be expanded to include patients who strongly desire Gamma Knife therapy.

Gamma Knife Radiosurgery for Pituitary Adenomas Invading the Cavernous Sinus: Tokyo Women's Medical University Experience.

Total surgical removal of a pituitary adenoma (PA) invading the cavernous sinus (CS) is challenging and carries a significant risk of postoperative complications. As an alternative treatment strategy, after incomplete resection, such tumors may undergo stereotactic radiosurgery-in particular, Gamma Knife surgery (GKS). Treatment planning based on advanced neuroimaging (e.g., thin-slice 3-dimensional postcontrast constructive interference in steady state (CISS) images) allows clear visualization of the target microanatomy, which results in highly conformal and selective radiation delivery to the lesion with preservation of adjacent functionally important neurovascular structures. In the Tokyo Women's Medical University experience of GKS for 43 nonfunctioning and 46 hormone-secreting PA invading the CS, with a minimum follow-up period of 5 years (mean 76 months, range 60-118 months), the tumor control rate has reached 97%, and a significant volume reduction (≥50%) has been seen in 24% of lesions. In cases of hormone-secreting neoplasms, normalization (in 18 patients; 39%) or improvement (in 22 patients; 48%) of endocrinological function has been noted. Importantly, such effects have been sufficiently durable. Complications have been extremely rare and limited to transient cranial nerve palsy (in 2% of cases). Notably, no patient in our series has had a new pituitary hormone deficit after irradiation. Thus, subtotal resection followed by GKS may be considered a valuable alternative to aggressive surgery for a PA invading the CS.

Gamma Knife Radiosurgery for Symptomatic Cavernous Malformations: Tokyo Women's Medical University Experience.

OBJECTIVE: This retrospective study evaluated the results of Gamma Knife surgery (GKS) for symptomatic cavernous malformations (CM) of the brain. METHODS: From 1993 till 2014, 11 patients (mean age 44 years) with a symptomatic CM underwent GKS at Tokyo Women's Medical University. In six cases, the disease manifested with hemorrhaging. Seizures and a neurological deficit were noted in four patients each. The CM were located in the brainstem (in 5 cases), basal ganglia (in 2 cases), thalamus (in 2 cases), and cerebral lobe (in 2 cases). The mean lesion volume was 1.46 cc. The mean marginal dose was 15.3 Gy. The mean length of follow-up after GKS was 78.5 months. RESULTS: At the last follow-up, the general status was considered excellent, fair, and poor in 8 patients (73%), 1 patient (9%), and 2 patients (18%), respectively. The annual hemorrhage rates per case-year were 2.94% from birth till GKS, 20.20% from the first hemorrhage till GKS, 4.54% within the first 2 years after GKS, and 1.39% within the entire follow-up period after GKS. Two patients attained seizure-free status after treatment. CONCLUSION: GKS may be considered as a possible management option for symptomatic CM, since it reduces the subsequent hemorrhage risk after the initial bleeding episode. Moreover, in some patients, cessation of symptomatic epilepsy after treatment may be expected.

Results of surgical treatment after Gamma Knife radiosurgery for cerebral arteriovenous malformations: patient series.

BACKGROUND: Gamma Knife radiosurgery (GKRS) is a safe and effective treatment, but it has a risk of bleeding. Herein, the authors describe their experience with some patients who required surgical removal of cerebral arteriovenous malformations (AVMs) located mainly in eloquent areas of the brain after GKRS, and they consider the advantages of surgical removal after GKRS. OBSERVATIONS: Twelve patients who had undergone surgical removal of AVMs after GKRS at Tokyo Women's Medical University between April 2013 and July 2019 were selected for analysis. All participants underwent GKRS as first-line therapy for AVMs located in an eloquent region or if requested by the patient. Complete obliteration was achieved in 7 patients, and the size of the nidus decreased in 3 patients during the follow-up period. The Spetzler-Martin grade decreased in 11 patients. Three patients experienced symptomatic intracerebral hemorrhage before and after confirmation of complete obliteration of the nidus via GKRS, and 7 patients experienced some neurological deficits because of an encapsulated expanding hematoma. All patients underwent resection of the nidus without complications. The preoperative neurological deficits improved in 6 patients and remained unchanged in 6 patients. LESSONS: This report indicates that performing GKRS before surgery may be useful for future multimodal therapy.

Gamma Knife treatment of malignant infantile brain tumors - Case report.

Stereotactic radiosurgery (SRS) is a treatment option, which is capable of pinpoint irradiation and thus, reduce the potential late complications. However, any type of radiation therapy is not recommended for brain tumor patients under the age of 3 years. SRS is not routinely recommended for patients than 2 years of age in consideration of infant skull brittleness for frame fixation, and lack of treatment evidence for the safety and effects of stereotactic radiosurgery in infants. We experienced the case of Gamma Knife treatment upon an infantile pineoblastoma where repeated tumor excision had already been perfromed and chemotherapy resistance was apparent. Radiosurgery resulted in symptom improvement and dramatic tumor shrinkage on MRI after radiosurgery. Therefore, here we report on the difficulty and usefulness of Gammaknife radiosurgery in this infant patient.

Hearing Preservation after Low-dose Gamma Knife Radiosurgery of Vestibular Schwannomas.

The objective of the retrospective study was to evaluate the factors associated with hearing preservation after low-dose Gamma Knife radiosurgery (GKS) of vestibular schwannomas performed according to the modern standards. From January 2005 to September 2010, 141 consecutive patients underwent such treatment in Tokyo Women's Medical University. Mean marginal dose was 11.9 Gy (range, 11-12 Gy). The doses for the brain stem, cranial nerves (V, VII, and VIII), and cochlea were kept below 14 Gy, 12 Gy, and 4 Gy, respectively. Out of the total cohort, 102 cases with at least 24 months follow-up were analyzed. Within the median follow-up of 56 months (range, 24-99 months) the crude tumor growth control was 92% (94 cases), whereas its actuarial rate at 5 years was 93%. Out of 49 patients with serviceable hearing on the side of the tumor before GKS, 28 (57%) demonstrated its preservation at the time of the last follow-up. No one evaluated factor, namely Gardner-Robertson hearing class before irradiation, Koos tumor stage, extension of the intrameatal part of the neoplasm up to fundus, nerve of tumor origin, presence of cystic changes in the neoplasm, and cochlea dose demonstrated statistically significant association with preservation of the serviceable hearing after radiosurgery. In conclusion, GKS of vestibular schwannomas performed according to the modern standards of treatment permits to preserve serviceable hearing on the side of the tumor in more than half of the patients. The actual causes of hearing deterioration after radiosurgery remain unclear.

[Pediatric medulloblastoma presenting as cerebellar hemorrhage: a case report].

Medulloblastomas usually cause cerebellar ataxia and acute hydrocephalus owing to their increase in size. Cerebellar hemorrhage is an extremely rare initial clinical presentation of medulloblastoma. Herein, we report a case of medulloblastoma in an 8-year-old girl who presented with initial cerebellar intratumoral hemorrhage. The patient initially presented with mild headache;the differential diagnosis by using the initial computed tomography and magnetic resonance images was difficult, as bleeding from a cerebellar vascular malformation(cavernous angioma or arteriovenous malformation)was considered more likely. Hydrocephalus or typical findings indicative of medulloblastoma were not observed. We initially only observed the patient at another institution because the hematoma was relatively small(1.5×1×1cm). After follow-up imaging for pathological diagnosis, surgical removal was performed at our institute 49 days after the hemorrhage was observed. Complete tumor removal was achieved, and the histopathological diagnosis was medulloblastoma. The patient received whole brain and spinal irradiation(23.4Gy;posterior fossa local:50.4Gy)and chemotherapy(cyclophosphamide, 1,000mg/m2/day on day 1;vincristine, 1.5mg/m2/day on day 1;etoposide, 100mg/m2/day on days 1-3;cisplatin, 90mg/m2/day on day 2). No recurrences or neurological deficits were observed during a 2-year follow-up. This was a rare case of medulloblastoma presenting as cerebellar hemorrhage. Cerebellar medulloblastoma is among the common pediatric brain tumors;therefore, it should be diagnosed accurately and quickly.

Do we really still need an open surgery for treatment of patients with vestibular schwannomas?

BACKGROUND: Gamma Knife surgery (GKS) should be considered a standard treatment option for small and medium-sized vestibular schwannomas (VSs). It results in a tumor control rate similar to that seen with microsurgery and provides better preservation of facial nerve function and hearing. METHODS: From December 2002 to April 2011, a total of 260 patients with VS underwent GKS using Leksell Gamma Knife model 4C with an automatic positioning system. There were 30 Koos stage I tumors, 112 stage II, 100 stage III, and 18 stage IV. All patients were treated with the use of high-resolution magnetic resonance imaging; creation of the highly precise conformal and selective multi-isocenter dose planning with small collimators, carefully sparing adjacent cranial nerves of any excessive irradiation; and creation of a wide 80 % isodose area within the tumor while applying a low marginal dose (mean 11.9 Gy) at the 50 % isodose line. RESULTS: Among 182 patients who were followed for more than 3 years after treatment, the tumor control and shrinkage rates were 98.4 % and 76.4 %, respectively. Volume reduction of >50 % was marked in 54.9 % of VSs. Preservation of facial nerve function and hearing at the pretreatment level was noted in 97.8 % and 87.9 %, respectively. There was marked improvement of facial nerve function and hearing after GKS in 2.2 % and 3.8 %, respectively. There was no major morbidity. CONCLUSION: Due to contemporary technological and methodological achievements GKS can be focused not only on growth control but on shrinking the VS, with possible reversal of the neurological deficit.

Usefulness of the advanced neuroimaging protocol based on plain and gadolinium-enhanced constructive interference in steady state images for gamma knife radiosurgery and planning microsurgical procedures for skull base tumors.

BACKGROUND: Gamma Knife radiosurgery (GKS) is currently performed with 0.1 mm preciseness, which can be designated microradiosurgery. It requires advanced methods for visualizing the target, which can be effectively attained by a neuroimaging protocol based on plain and gadolinium-enhanced constructive interference in steady state (CISS) images. METHODS: Since 2003, the following thin-sliced images are routinely obtained before GKS of skull base lesions in our practice: axial CISS, gadolinium-enhanced axial CISS, gadolinium-enhanced axial modified time-of-flight (TOF), and axial computed tomography (CT). Fusion of "bone window" CT and magnetic resonance imaging (MRI), and detailed three-dimensional (3D) delineation of the anatomical structures are performed with the Leksell GammaPlan (Elekta Instruments AB). Recently, a similar technique has been also applied to evaluate neuroanatomy before open microsurgical procedures. RESULTS: Plain CISS images permit clear visualization of the cranial nerves in the subarachnoid space. Gadolinium-enhanced CISS images make the tumor "lucid" but do not affect the signal intensity of the cranial nerves, so they can be clearly delineated in the vicinity to the lesion. Gadolinium-enhanced TOF images are useful for 3D evaluation of the interrelations between the neoplasm and adjacent vessels. Fusion of "bone window" CT and MRI scans permits simultaneous assessment of both soft tissue and bone structures and allows 3D estimation and correction of MRI distortion artifacts. CONCLUSION: Detailed understanding of the neuroanatomy based on application of the advanced neuroimaging protocol permits performance of highly conformal and selective radiosurgical treatment. It also allows precise planning of the microsurgical procedures for skull base tumors.

Outcome after Gamma Knife surgery for intracranial arteriovenous malformations in children.

OBJECT: The focus of the present study was the evaluation of outcomes after unstaged and staged-volume Gamma Knife surgery (GKS) in children harboring intracranial arteriovenous malformations (AVMs). METHODS: Twenty-two children (median age 9.5 years) underwent GKS for AVMs and were followed up for at least 2 years thereafter. The disease manifested with intracranial hemorrhage in 77% of cases. In 68% of patients the lesion affected eloquent brain structures. The volume of the nidus ranged from 0.1 to 6.7 cm(3). Gamma Knife surgery was guided mainly by data from dynamic contrast-enhanced CT scans, with preferential targeting of the junction between the nidus and draining vein. The total prescribed isodose volume was kept below 4.0 cm(3), and the median margin dose was 22 Gy (range 20-25 Gy). If the volume of the nidus was larger than 4.0 cm(3), a second radiosurgical session was planned for 3-4 years after the first one. Nine patients in the present series underwent unstaged radiosurgery, whereas staged-volume treatment was scheduled in 13 patients. RESULTS: Complete obliteration of the AVM was noted in 17 (77%) of 22 patients within a median period of 47 months after the last radiosurgical session. Complete obliteration of the lesion occurred in 89% of patients after unstaged treatment and in 62.5% after staged GKS. Four (67%) of 6 high-grade AVMs were completely obliterated. Complications included 3 bleeding episodes, the appearance of a region of hyperintensity on T(2)-weighted MR images in 2 patients who had no symptoms, and reappearance of the nidus in the vicinity of the completely obliterated AVM in 1 patient. CONCLUSIONS: Radiosurgery is a highly effective management option for intracranial AVMs in children. For larger lesions, staged GKS may be applied successfully. Initial targeting of the nidus adjacent to the draining vein and application of a sufficient radiation dose to a relatively small volume (≤ 4 cm(3)) provides a good balance between a high probability of obliteration and a low risk of treatment-related complications.

Gamma knife radiosurgery for benign cavernous sinus tumors: treatment concept and outcomes in 120 cases.

Availability of modern computer-aided robotized devices, such as the Automatic Positioning System (APSTM; Elekta Instruments AB, Stockholm, Sweden) and PerfexionTM (Elekta Instruments AB), allowed us to develop the original concept of robotic gamma knife microradiosurgery, which is based on the very precise irradiation of the lesion with regard to conformity and selectivity; intentional avoidance of the excessive irradiation of functionally-important anatomical structures, particularly cranial nerves, located both within and in the vicinity of the target; and delivery of sufficient irradiation energy to the tumor with the intention to attain lesion shrinkage, while keeping the marginal dose sufficiently low for prevention of possible complications. The results of such treatment strategy were evaluated retrospectively in 120 patients with benign cavernous sinus neoplasms (pituitary adenomas, meningiomas, schwannomas, and hemangiomas), who were followed up from 24 to 78 months (mean 47 months) after radiosurgery. Tumor growth control and shrinkage rates were 98% and 68%, respectively. More than 50% volume reduction was noted in 25% of lesions. The most prominent volumetric tumor response was observed in hemangiomas, followed by schwannomas, pituitary adenomas, and meningiomas. Treatment-related complications were marked in 7% of cases, and were mainly related to transient isolated cranial neuropathy appearing within several months after radiosurgery. Major morbidity was limited to one patient (0.8%). Application of microradiosurgical treatment principles provides effective and safe management of benign cavernous sinus tumors and is associated with high probability of lesion shrinkage and minimal risk of complications.

Ruptured infectious aneurysms of the distal MCA treated with trapping and STA-MCA bypass surgery.

We describe two patients with ruptured infectious aneurysms of the distal MCA, which were successfully treated by trapping and superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery. Our patients had not experienced any ischemic attack postoperatively. Trapping and STA-MCA bypass surgery can be a useful option.

Detection of ophthalmic artery occlusion by visual evoked potential during carotid-ophthalmic artery aneurysm clipping.

We report an intriguing case of carotid-ophthalmic artery (OA) aneurysm surgery, in which the visual evoked potential (VEP) wave diminished during temporary OA occlusion. VEP waves suddenly disappeared after clipping, and repositioning of the clip restored blood flow to the OA and recovered the VEP wave.

Moyamoya disease complicated by Graves' disease and type 2 diabetes mellitus: report of two cases.

The pathogenesis of moyamoya disease remains unknown. Examination of diseases concurrent with moyamoya disease may offer a clue to clarify the pathogenesis. Coexistence of moyamoya disease, Graves' disease, and diabetes mellitus is very rare. We present the first cases in the literature. A 38-year-old man with moyamoya disease and a 43-year-old woman with quasi-moyamoya disease, both concurrent with Graves' disease and type 2 diabetes mellitus, are presented. Both patients underwent antithyroid therapy and revascularization. After normalization of thyroid hormones level and blood glucose level followed by revascularization, the symptoms of cerebral ischemia were improved. The common etiological factors of these diseases are discussed. Genetic and autoimmune factor appeared to be involved in the pathogenesis of the three diseases, which may suggest that these factors play important roles in the pathogenesis of moyamoya disease. Further studies are required to define the pathogenesis of moyamoya disease, especially in cases with comorbidities as in the present patients.