Clinical Analysis of Novalis Stereotactic Radiosurgery for Brain Metastases

OBJECTIVE: The authors analyzed the effectiveness and therapeutic response of Novalis shaped beam radiosurgery for metastatic brain tumors, and the prognostic factors which influenced the outcome. METHODS: We performed a retrospective analysis of 106 patients who underwent 159 treatments for 640 metastatic brain lesions between January 2000 and April 2008. The pathologies of the primary tumor were mainly lung (45.3%), breast (18.2%) and GI tract (13.2%). We classified the patients using Radiation Therapy Oncology Group Recursive Partitioning Analysis (RPA) and then analyzed the survival and prognostic factors according to the Kaplan Meier method and univariate analysis. RESULTS: The overall median actuarial survival rate was 7.3 months from the time of first radiosurgery treatment while 1 and 2 year actuarial survival estimates were 31% and 14.4%, respectively. Median actuarial survival rates for RPA classes I, II, and III were 31.3 months, 7.5 months and 1.7 months, respectively. Patients' life spans, higher Karnofsky performance scores and age correlated closely with RPA classes. However, sex and the number of lesions were not found to be significantly associated with length of survival. CONCLUSION: This result suggests that Novalis radiosurgery can be a good treatment option for treatment of the patients with brain metastases.

Idiopathic Hypertrophic Spinal Pachymeningitis: A Case Report

Idiopathic hypertrophic pachymeningitis (IHP) is a rare, chronic nonspecific and granulomatous inflammatory disorder of the dura with unknown etiology. The diagnosis can be established by open biopsy and exclusion of all other specific granulomatous and infectious diseases. We report a typical case of spinal IHP occurring in a long segment of cervical and thoracic dura from C6 to T8. The patient was 56-yr-old female, who had been suffered from pain on her upper back and both arms for 3 months and recent onset motor weakness of both legs. During the 9 months of follow-up period, she experienced the improvement of her neurologic symptoms with combined therapy of partial excision and corticosteroid medication. Since early surgical intervention and subsequent pulse ste-roid therapy are mandatory for this disease to avoid irreversible damage of nervous system, the identification of this unique disease entity is essential on frozen diagnosis. A few cases have been reported in Korean literature.

Evaluation of Preoperative Embolization of Meningioma

PURPOSE: To evaluate the efficacy and safety of preoperative embolization of intrancranial meningioma. MATERIALS AND METHODS: We retrospectively reviewed intrancranial meningioma patients (n=37) who underwentpreoperative embolization. They were categorized into two groups, skull base lesions (n=22) and non-skull baselesions (n=15), according to tumor location. In addition, embolization results were classified by comparisonbetween pre- and post-embolization angiography as complete (residual tumor staining or= 10 or 30%). In each group, estimated blood loss (EBL) was estimated by amount ofintraoperative transfusion with pre- and post-operative hemoglobin level. Tumor resectability was evaluated byfollow-up computed tomography. New symptoms occurring within 24 hours of embolization were considered to be thoseassociated with embolization ; symptoms improved by conservative treatment were regarded as mild, while thoseresulting in new deficits were considered severe. RESULT: In the group with skull base lesions (n=22), completeembolization with the criteria of residual tumor staining of less than 30% was performed in 14 patients(EBL=1770ml;complete surgical removal in nine patients and incomplete removal four). Incomplete embolization wasperformed in eight patients (EBL=3210ml; complete and incomplete removal each in four patients). In the group withnon-skull base lesions, complete embolization with the criteria of residual tumor staining of less than 10% wasperformed in five patients (EBL=970ml) and incomplete embolization in ten (EBL=2260ml). Complete tumor removal waspossible in this group regardless of the completeness of preoperative tumor embolization. In a case ofintraventricular meningioma (3%), intratumoral hemorrage occurred on the day following embolization. Other mildpost-embolization complications occurred in three cases (8%). CONCLUSION: Preoperative embolization can be aneffective and safe procedure for meningioma and may reduce intraoperative blood loss. Its effectiveness may dependon tumor location and the degree of embolization, though the procedure seems to be helpful for lseions at theskull base.

Cranial Chordoma ; Clinical Presentation and Multimodality Treatment

Cranial chordomas are rare and generally slow-growing malignant neoplasms of presumed notochordal origin. They seldom metastasize, but are difficult to manage because of their locally invasive nature and their proximity to critical structures. The clinical presentation and results of operative treatment, radiation therapy, and radiosurgery in a series of 10 patients with cranial chordomas seen at our hospital, between June 1989 and December 1994, are analysed. There were 4 men and 6 women with a mean age of 37.5 years. The most common presenting symptoms were visual loss, motor weakness and diplopia, and the most common presenting sign was visual field defect. The mean interval between symptom onset and initial treatment was 4.8(1-17) months. Three tumors classified as the chondroid type showed better clinical course. Extent of tumor resection included biopsy in 1 patient and subtotal or greater in 9. Four patients received postoperative radiation therapy and 4 patients stereotactic radiosurgery using Leksell gamma unit. Among them 1 patient showed tumor progression after radiation therapy but none after radiosurgery. One patient died due to tumor recurrence and two patients due to therapy but none after radiosurgery. One patient died due to tumor recurrence and two patients due to postoperative complications. At the time of analysis 7 patients were alive. The average length of follow-up for the alive patients was 34 months. The results of this study suggest that multimodality treatment using surgical debulking, radiation therapy and stereotactic radiosurgery is necessary for the optimal management of chordoma.

Improved Access to Skull Base Tumors by Resection of the Zygoma

Improved access to lesions at the medial end of the sphenoid ridge, in the cavernous sinus, or in the interpeduncular cistern after mobilization of the zygoma has been a subject of growing interest in recent years. This study described out experience with 23 patients who underwent the zygomatic osteotomy for skull base tumors in the past 6 years. The follow-up period ranged from 5 months to 49 months. The patient' age range was 11 to 75 years, with an average age of 45 years. This zygomatic osteotomy was used from eleven patients with medial sphenoid ridge lesions, six with lesions arising in or involving the cavernous sinus, three with clival lesions, two with sellar/parasellar lesions, and one with temporal lobe lesions. The histology of these patients showed fourteen meningiomas, two pituitary adenomas, two chordomas, one neurinoma, one chondrosarcoma, one osteochondroma, one malignant lymphoma, and one dermoid cyst. Surgical treatment consisted of total removal in ten patients, subtotal removal in twelve, and partial removal in one. Instances of morbidities associated with basic lesions included cranial nerve injury in five patients, hemorrhage/infarction in three, hemiparesis in two, and transient aphasia in one. There were no significant problems related to zygomatic osteotomy. One patient who underwent zygomatic osteotomy for medial sphenoid ridge meingioma developed a frontalis nerve injury. No patient experienced a detachment of zygomatic arch in our series. Postoperatively, one patient with parasellar malignant lymphoma died 14 months after surgery from tumor progression. Our cases treated via this zygomatic osteotomy are as yet insufficient to determine whether the method offers definite adventages, in terms of patient mortality and morbidity, over conventional operative approaches, but we suggest that this procedure has some advantages such as minimal brain retraction, exposure of lesion in shortest distance, multidirectional viewing of the lesions, and can serve as an alternative approach to a usual pterional approach when cranial base pathologies are large or complex.

Classification and Surgical Treatment of Paraclinoid Aneurysms

Paraclinoid aneurysms arose from the proximal internal carotid artery between the site of emergence of carotid artery from the roof of the cavernous sinus and posterior communicating artery. Surgery of these aneurysms presents special difficulties because of its complicated osseous, dura, and neurovascular structures;sella turcica, cavernous sinus, optic nerve. The clinical and radiological characteristics in twenty-seven patients with the paraclinoid aneurysms were reviewed and classified into four subgroups according to their branch of origin in this segment;1) carotid cave aneurysm(2 cases), 2) ophthalmic artery aneurysm(11 cases), 3) superior hypophyseal artery aneurysm(11 cases), 4) proximal posterior carotid artery wall aneurysm or global type aneurysm(3 cases). Surgery required orbital unroofing and removal of anterior clinid process with release of dural ring. To provide easy proximal control, exposure of cervical carotid artery was helpful in some cases. Preoperative balloon occlusion testing was man datory. Outcomes were considered as good to fair in 19 patients, poor in five, and three patients died. The patients who had poor results were poor preoperative status-four were grade IV, one was grade II(Hunt-Hess grade). The causes of death were premature rupture(2 cases) and extensive vasospasm(1 case). Preoperative classification of these lesions provides excellent correlation of operative findings and surgical preparation to expose the proximal part of internal carotid artery.

Effect of High-Dose Tamoxifen on Malignant Gliomas

In vitro studies have shown that the nonsteroidal antiestrogen tamoxifen can suppress deoxyribonucleic acid(DNA) synthesis and cell proliferation in cultured human gliomas. This growth suppression is independent on its antiestrogenic properties. Tamoxifen may act through the inhibition of the enzyme protein kinase C(PKC), which transduces mitogenic signals from the cell surface to the nucleus. In order to evaluate the therapeutic response and side effect of high-dose tamoxifen, we performed a clinical study of 28 patients with malignant gliomas who were treated with high-dose tamoxifen in our hospital between February 1991 and January 1993. An effect was defined as a statistically improved survival times/rates. In patients who were assigned to receive high-dose tamoxifen, it was first administered at standard antiestrogen doses(20mg orally bid/day) to observe for any side effect and if tolerated, the dose was increased weekly to achieve target doses(100mg orally bid/day) over a 1 month period. We compared the survival times/rates between anaplastic astrocytomas and glioblastoma mutiformes. Although the median survival time was slightly longer in anaplastic astrocytomas than that of glioblastoma multiformes, there was no statistical difference of survival curves between two groups at the p=0.05 level. We also examined the survival times/rates of malignant gliomas according to treatment modalities(radiotherapy alone, radiotherapy plus ACNU, and radiotherapy plus tamoxifen). Although the survival rate and time were slightly higher in radiotherapy plus tamoxifen group than those of another treatment groups, we could not find the statistical significance of survival curves between three treatment groups(p>0.05). High-dose oral tamoxifen appeared to be well tolerated in most patients. Five patients developed anorexia following dose escalation of tamoxifen. Another complications were amenorrhea, nausea/vomiting, and constipation. There were no changes in hematological studies that could be attributed to tamoxifen. We think that high-dose tamoxifen cah be administered safely to malignant gliomas patients. Our results were not impressive. We conclude that the definition of the true efficacy of high-dose tamoxifen in patients harboring malignant gliomas is not possible from this limited study, and a further large scale, randomized trial of this agent is necessary.

Anterior Approaches to Midline Skull Base Tumors

Among various approaches to midline skull base tumors, anterior approaches can provide excellent visualization of the lesion. Since June 1989, 12 anterior procedures have been carried out on 9 consecutive patients presenting with midline skull base tumors(four transsphenodal approches, three Le Fort I osteotomies. Two lateral rhinotomies, two facial translocation approaches, and one craniofacial approach). These anterior procedures allowed good access to the lesions. Wound healing was rapid, with little discomfort to the patients. Cosmetic results were also excellent, and there were no significant problems related to malocclusion in the cases of Le Fort I osteotomy. Patients who underwent facial translocation approach developed nasolacrimal duct obstruction and small area hypesthesia on the cheek. Postoperatively, two patients died from tumor progression and meningitis secondary to CSF leakage, respectively. Although the number of cases and follow-up period are limited in our series, we think that anterior approaches may be useful in the surgical treatment to midline skull base tumors.

Surgical Management of Unruptured Intracranial Aneurysms

With the ever- increasing number of intact aneurysms revealed by modern imaging, the options for their management are assuming greater importance. The surgical management of patients with unruptured intracranial aneurysms continues to be contoversial, and the criteria for withholding treatment or choosing between endovscular embolization and conventional microsurgery are not well delineated. In order to define the surgical result for unruptured intracranial aneurysms, 41 patients(from June 1989 to May 1995) with surgically treated unruptured aneurysms were analyzed. They were categorized as incidental, multiple or aneurysm with mass effect. Subarachnoid hemorrhage from another aneurysm(multiple) was the most common presentation(19 patients). Eleven patients were presented with incidental findings unrelated to aneurysmal subarachnoid hemorrhage or direct aneurysmal mass effect, and 11 patients were presented with mass effect such as cranial nerve palsy or brain stem compression. We could perform direct neck clipping presented with mass effect such as cranial nerve palsy or brain stem compression. We could perform direct neck clipping with without wrapping in 37 patients, trapping in 2, and wrapping in 1. One patient with giant vertebrobasilar artery aneurysm(greater than 25mm in diameter) which was presented with mass effect could not be treated adequately. Instances of morbidity included cranial nerve injury in 4 patients, hemiparesis in 3, hematoma in 2, and major hemispheric infarction in 1. One patient presented with mass effect, died from major hemispheric infarction after surgery of proximal internal carotid artery aneurysm with a size greater than 25mm in diameter. Two patients, who underwent surgery for giant vertebrobasilar artery aneurysms presented with mass effect, were in poor state due to persistent cranial nerve palsy and homiparesis. In general overall outcome was very good. Excellent or good outcome was achieved in 38 patients(92.7%) while 3 patients(7.3%) either died or was/were in poor condition. The aneurysm size was correlated well with the surgical outcome. We have achieved excellent or good out comes in 100% of patients with aneurysms 25mm or less in diameter. However, with aneurysms greater than 25mm in diameter, the outcomes were very poor with 75% of these patients in poor state or dead. "Surgery in unruptured aneurysms?" The answer was "Yes". We believe the size and location of the aneurysm are the key predictons of risk for sugical morbidity.

Brain-Stem Gliomas:Growth Patterns, Pathology, and Prognosis

A retrospective study of 29 cases of brain-stem gliomas(BSG's) from 1989 to 1993, was performed to determine prognostic factors. Our study also analyzed clinical features, growth patterns, pathologic findings and modalities of treatment in patients with brain-stem gliomas. The patients ranged in age from 6 to 65 years, most commonly in the first decade. The symptom duration prior to diagnosis was 1/2 to 6 months(mean 1 1/2 months). The most common symptom and sign were cranial nerve palsies, especially 6th or 7th cranial nerve. The growth patterns of BSG's were classified into diffuse tumors(7 patients), exophytic(9 patients), focal(2 patients) and cervicomedullary(1 patient). Twenty three of 29 patients were diagnosed pathologically by means of stereotactic biopsy(13 patients) and ope surgery(10 patients). The Pathologic findings were low grade astrocytoma in 9 patients, oligodendroglioma(3 patients), malignant astrocytoma(7 patients), and glioblastoma mulitiforme(4 patients). A significant correlation between diffuse growth pattern and malignant pathologic finding could be obtained(P=0.05). The methods of radiation therapy for BSG's were conventional(10 patients), hyperfractionated(13 patients), and Gamma knife radiosurgery(6 patients). The median survival time was 12 months. The Poor prognostic factors determined in our study were 1) short symptom duration prior to diagnosis(< or = 2 months), 2) diffuse growth pattern, 3) malignant pathologic finding, 4) tumor without cystic portion, and 5) tumor without hydrocephalus.

Analysis of Treatment Results for Pineal Region Tumors

The authors think that the more desirable treatment for pineal region tumors is definitive surgery with a histological diagnosis and that a conservative approach consisting of shunting and radiation therapy no longer seems to be appropriate. We report the result of a retrospective review of the presentation, treatment, and outcome of the seventeen patients treated between June, 1989 and June, 1994. Nine patients were males and eight patients were females, and the age ranged from 13 to 51 years(mean age about 32 years old). Histological verification was available in fourteen tumors;six by an occipital transtentorial approach and five by an infratentorial supracerebellar approach and two by a stereotaxic biopsy and one by a frontotemporal craniotomy for ectopic germinoma. Germinomas were the most common type. Three of the seventeen patients died of tumor progression. Because the great variety of tumor found in the pineal region must be treated in different ways and because improved microsurgical and stereotaxic surgical techniques have made mortality and morbidity rates acceptably low, a biopsy diagnosis should be obtained.

Surgical Result for Ruptured Anterior Circulation Aneurysms in Elderly Patients

In order to define the surgical result for ruptured anterior circulation aneurysms in the elderly, 59 patients(from June 1989 to May 1994) whose age was 66 years of age or older were analyzed. The factors which might influence the outcome were statistically compared between those aged 66 years or older(elderly patients group:59 patients:12.5%) and those aged 65 years or younger(younger patients group :413 patients;87.5%);the clinical grading, the location of aneurysms, the multiplicity, the presence of the angiographic vasospasm, the development of the symptomatic vasospasm, the presence of the hypertension. Fisher's grade IV(intracerebral hemorrhage or intraventricular hemorrhage), and the timing of surgery. Overall outcome between two groups was not different significantly, and many factors did not affect the outcome except the location. Surgical outcome in good grade patients(Hunt and Hess Grade I, II) was excellent regardless of age and timing of surgery. "Early surgery in the elderly?" The answer was Yes especially in good grade patients. We conclude that surgical outcome for ruptured anterior circulation aneurysms in the elderly does not seem to be directly affected by age, so elderly patients need not therefore be excluded from the benefits of surgery just because of their chronological age. It is principally the patient's condition during the acute stage that determine the surgical outcome.

Gamma knife radiosurgery for malignant tumors

Between May 1990, and June 1994, 79 patients with malignant tumors were treated radiosurgically using a Leksell gamma unit at Asan Medical Center. Of these patients, 57 were metastatic brain tumor, 12 were glioblastoma multiforme (GM), 4 were primitive neuroectodermal tumor, 3 were malignant germ cell tumor, 2 were recurrent lymphoma, and 1 was adenoid cystic carcinoma of the orbit. Among 57 patients with metastatic tumors, 28 patients harboring 60 tumors were followed clinically and radiographically. The median marginal dose for these tumors was 30 Gy and the median survival rate was 15 months. Twenty-one tumors disappeared and 32 tumors decreased in size during 2 to 6 months after radiosurgery on computed tomographic or magnetic resonance imaging scans. All 12 patients with GM were treated with conventional radiation (6,240 approximately 6,500 cGy) after surgical resection or biopsy prior to radiosurgery (13 approximately 15 Gy to margin). The results were varied. Radiosurgical treatment of two recurrent lymphomas and three recurrent mixed germ cell tumors after radiation and chemotherapy provided rapid clinical improvement with disappearance of the tumor. However, new lesions appeared in two lymphomas and one mixed germ cell tumor within 3 to 4 months. One patient with adenoid cystic carcinoma of the orbit, who was treated radiosurgically prior to resection, is alive without recurrence 31 months after the treatment. Gamma knife radiosurgery appears to be the best alternative method to surgical excision plus radiation therapy for single and multiple cerebral metastases. It also provides rapid palliation of symptoms due to recurrent malignant tumors. And it may have an adjuvant role in the treatment of some tumors delaying local recurrence, if given prior to resection. However, the preliminary results for the malignant gliomas were inconclusive.

Surgical Mangagement of Brainstem Hematoma Caused by Angiographically Occult Vascular Malformation(AOVM)

Brain stem hematomas, expecially due to ruptured angiographically occult vascular malformation(AOVM), are of great interest because they are potentially curable. Preoperative diagnosis has been difficult due to poor resolution of CT scans in the posterior fossa region. The advent of MRI has made the identification of the angiographically occult vascular malformation possible before surgical excision. We preset 3 cases of brainstem hematoma due to vascular malformations which wre not visualized by angiography but were diagnosted by MRI. The patients were treated surgically and vascular malformations were confirmed.

Clinical Experience of Rathke's Cleft Cysts

Rathke's cleft cysts(RCCs) are classically described as benign epithelium-lined intrasellar cysts containing mucoid material. They are thought to orignate from remamants of the Rathke's pouch. These cysts are most frequently small and asymptomatic, and generally regarded as rare lesions. With the introduction of modern neuroimaging technology, they are being diagnosed much more frequently. We reviewed clinical, radiographic, and pathological findings in nine patients with symptomatic RCCs who were treated at out hospital from June 1989 to October 1994. The lesions were more often encountered in female than male patients, and the mean age at presentation was 25 years. The most common symptom and sign were headache, visual disturbance, and pituitary dysfunction. Two cysts were entirely intrasellar and seven had intra- and suprasellar components. Pre-enhanced CT scans revealed low dense or isodense lesions in five cases, and contrast-enhanced CT scans showed ring enhancement in two of five cases. MRI findings were varied with no characteristic pattern. Six patients underwent surgery by the transsphenoidal approach, and another three patients were treated by the transcranial approach. Partial excision and drainage of the cysts was most commonly performed, and there was no cyst recurrence. The cyst lining was usually composed of couboidal or columnar epithelium. Most symptoms and signs improved or resolved following surgery with the exception of hypopituitarism. Because of the relative safety and low recurrence rate, we think that partial excision and drainage of the cyst by the transsphenoidal approache is the treatment of choice.

Effect of ACNU Chemotherapy on Malignant Glioma

In order to determine if there was an enhancing therapeutic effect of ACNU(1-4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride, nimustine chloride given in addition to radiotherapy, we performed a randomized clinical study of irradiation alone and combination of irradiation with ACNU in the treatment of malignant gliomas. Thirty-seven patients who were treated in our hospital from August 1990 to September 1992 were included in this study. An effect was defined as a statistically improved survival times. Radiotherpy with a total dose of 5000 to 6500 rads was applied to the whole brain and to a generous field surrounding the tumor. Patients who were assigned to receive chemotherapy were given ACNU intravenously at a dose of 1-2mg/kg. The survival rates of patients with anaplastic astrocytoma and glioblastoma multiforme at 18 months after the surgery were 0% and 37% for radiotherapy alone, and 66.7% and 40.1% for radiotherapy plus ACNU, respectively. The median survival times of patients with anaplastic astrocytoma and glioblastoma multiforme were 14 and 15 months for radiotherapy alone, and 19 and 16 months for radiotherapy plus ACNU, respectively. The survival rates of patients with malignant gliomas(anaplastic astrocytoma plus glioblastoma multiforme) at 18 months were 5.5% for radiotherapy alone and 45.4% for radiotherapy plus ACNU, and the median survival times were 15 and 16 months, respectively, Althouh the survival rate of patients with malignant gliomas at initial 6 months was much higher in radiotherapy plus ACNU than in radiotherapy alone, the differences between survival curves were not significant at the p=0.05 level. This study demonstrated that, although the use of ACNU during radiotherapy suppressed malignant gliomas more than radiotherapy alone, the survival time was not extended significantly. It is necessary to continue to search for an effective chemotherapapeutic regimen to prolong survival of patients with malignant gliomas.

The Role of Gamma Knife Radiosurgery for the Treatment of Pituitary Adenomas

The treatment of choice for symptomatic pituitary adenomas varies according to the hormone secreting types of the adenoma and can include pharmacology, surgery, or radiotherapy. The recent development of radiological imaging and microsurgery has made surgery the treatment of choice for most pituitary tumors. However, the long-term tumor control rate after microsurgery varies from 50% to as high as 80%. During the last 38 months(1990. 5-1990. 9., 1991. 5-1994. 2), 34 cases of pituitary adenomas were treated by gamma knife at Asan Medical Center. There were 11 cases of prolactinomas, 9 cases of acromegaly, 8 cases of ACTH-secreting tumors and 6 cases of non-functioning tumors. Seventeen patients underwent gamma knife radiosurgery for recurrent or remaining tumors after resective surgery. Another 17 patients were treated primarily with gamma knife. In microadenomas, the mean tumor volume was 221 cumm and the mean marginal dose was 33.1 Gy. In microadenomas, the mean tumor volume was 2690 cumm and the mean marginal dose was 2.6 Gy. Twenty-seven patients have had an average follow-up period of 26 months with a range from 3 to 48 months. As a result, five out of eight prolactinoma patients had normalization of prolactin hypersecretion and seven patients showed clinical cure. On follow-up imaging studies, five out of seven tumors showed no changes in their size, while two showed marked reduction. Two out of four ACTH-producing tumor patients showed normalization of 24 hour urine cortisol levels. On follow-up imaging studies of the two cases, the tumor of one patient disappeared and the other one showed no change. Three out of six acromegalic patients showed clinical responses. Two out of five non-functiong tumors showed reduction in size and three showed no changes. In conclusion, gamma knife radiosurgery seems to be effective as adjuvant therapy for the treatment of remaining or recurrent pituitary adenomas after surgery and primary treatment modality in selective patients.

Analysis of Inconclusive Diagnostic lesions in Stereotactic Biopsy: Review of Cases in 5 Years

While stereotactic biopsy increases the accuracy of obtaining appropriate tissue for precise diagnosis, inconclusive diagnostic lesions can still be observed frequently. We present a review of 43 patients with inconclusive diagnostic samples in stereotactic biopsy between June 1989 and June 1994. inconclusive diagnostic lesions were found in 43 patients(17.9%); the biopsy of these patients showed reactive gliosis in 22, foam cell infiltration and/or demyelination with coagulation necrosis in 8, chronic inflammatory cell infiltration with necrosis, fibrosis in 6, no evidence of tumor in 5, and ganglioglial lesion in 2. The final diagnosis was based on histological findings of permanent paraffin sections after rebiopsy or open surgery, close follow-up CT/MRI scan findings, clinical features and/or history, and serological studies;neoplasm 16, infarction/leukodystrophy 8, infection/inflammation 4, granuloma 1, and no confirmative diagnosis 4, In conclusion, rebiopsy or open surgery is recommended if the lesion is suspected to be a neoplasm, and the patient is closely observed with repeated radiological studies if the lesion is suspected to be benign. This study provides evidence that in some cases an accurate histopathological diagnosis can not be made with stereotactic biopsy and therefore, further investigations are needed in such inconclusive cases.

Hypertensive Cerebellar Hemorrhage:Prognostic Factors

Hypertensive cerebellar hemorrhage was rarely diagnosed in the past and therefore thought to be infrequent, but after the introduction of computerized tomography(CT) scans it has been more commonly diagnosed. We present 36 patients with hypertensive cerebellar hemorrhage who were treated in our hospital from June 1989 to January 1994. There were 15 men and 21 women, with ages ranging between 34 and 91 years. The volume of cerebellar hematoma and the grade of quadrigeminal cisternal obliteration on CT scans significantly correlated to the level of consciousness at admission. Several prognostic factors which might influence the outcome were statistically analysed:the level of consciousness at admission, the volume of hematoma, the treatment modality, the presence of hydrocephalus, the presence of quadrigeminal cisternal obliteration on CT scans, and the location of hematoma. Overall mortality rate was 13.9% and many of the above factors affected the outcome except for the treatment modality and the presence of hydrocephalus. The outcome in patients with GCS scores of 14 or 15 at admission was excellent. We conclude that the level of consciousness at admission is the most important prognostic factor and surgical decompression is indicated particularly in patients with an impaired level of consciousness, provided that brainstem reflexes are still intact. An accurate monitoring of the patient's clinical status is very important since its worsening is an absolute indication for surgery independent of the size of hematoma.

Large and Giant Paraclinoid Aneurysms Treated by Combined Extradural and Intradural Approach

Between May, 1992 and April, 1993, four patients with paraclinoid aneurysms were treated by a direct operative approach. Two patients had large aneurysms, all of which had ruptured, presented with subarachnoid hemorrhage(SAH). The other two patients had giant aneurysms, causing visual symptoms by optic nerve compression. All patients were treated by a combined extradural and intradural approach. All the aneurysms were successfully clipped and collapsed or resected, eliminating the risk of rebleeding and decompressing the visual system immediately and effectively, while preserving the blood flow of the carotid artery and its branches. Removal of the individual bony structure including anterior clinoid process(ACP) and orbital roof at the skull base extradurally provides a better and safer exposure of the aneurysm, and of the ophthalmic segment of the carotid artery than does excessive retraction of the brain. This technique also affords exposure of the internal carotid artery proximal to the lesion and ophthalmic artery, which is important in securing safe and complete occlusion of the aneurysm. Authors present operative technique, summary of cases, and literature review.