摘要:

THE MECHANISMS RESPONSIBLE for subarachnoid hemorrhage (SAH)-induced vasospasm are under intense investigation but remain incompletely understood. A consequence of SAH-induced vasospasm, cerebral infarction, produces a nonrecoverable ischemic tissue core surrounded by a potentially amenable penumbra. However, successful treatment has been inconsistent. In this review, we summarize the basic molecular biology of cerebrovascular regulation, describe recent developments in molecular biology to elucidate the mechanisms of SAH-induced vasospasm, and discuss the potential contribution of cerebral microcirculation regulation to the control of ischemia. Our understanding of the pathogenesis of SAH-induced vasospasm remains a major scientific challenge; however, molecular biological techniques are beginning to uncover the intracellular mechanisms involved in vascular regulation and its failure. Recent findings of microvascular regulatory mechanisms and their failure after SAH suggest a role in the development and size of the ischemia. Progress is being made in identifying the various components in the blood that cause SAH-induced vasospasm. Thus, our evolving understanding of the underlying molecular mechanism may provide the basis for improved treatment after SAH-induced vasospasm, especially at the level of the microcirculation.

ISSN:0148-396X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

RADIOSURGERY WILL CELEBRATE its Golden Jubilee in the year 2001. More than 100,000 patients throughout the world have undergone radiosurgery since Lars Leksell first described the technique in 1951. Rapid developments in neuroimaging and even robotic technology in the past decade have contributed to improved outcomes and wider applications for radiosurgery. A variety of different radiosurgical techniques have been developed in the past two decades. Numerous studies have examined the benefits and risks of radiosurgery performed with various devices. The long-term results of radiosurgery are now available, and these results have established radiosurgery as an effective noninvasive treatment method for intracranial vascular malformations and many tumors. Additional applications of radiosurgery for the treatment of malignant tumors and functional disorders are being assessed. Radiosurgery is an impressive combination of minimally invasive technologies administered by a multidisciplinary team of surgeons, oncologists, medical physicists, and engineers.

ISSN:0148-396X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

THE POOR PROGNOSIS associated with malignant astrocytoma has led investigators to seek new, innovative methods of treatment. Targeted toxins represent a unique form of therapy that has two components, a carrier molecule with high specificity for tumor-associated antigens and a potent protein toxin. These compounds are extremely cytotoxic to malignant astrocytoma cell lines in vitro. Animal studies have shown prolongation of survival and complete tumor regression when targeted toxins were administered by a variety of routes. The promising results seen in vivo have formed the basis for proceeding with clinical trials in humans with leptomeningeal neoplasia and malignant brain tumors, in which these agents are administered intrathecally or directly into tumor, respectively. To date, in these clinical trials, targeted toxins have been delivered safely without significant neurological toxicity, and cytological analysis of cerebrospinal fluid and radiological findings have shown evidence of a therapeutic response. These studies have confirmed the existence of a therapeutic window between normal brain tissue and malignant cells that can be exploited with targeted therapy directed against the transferrin receptor. The successful delivery of targeted toxins directly into malignant brain tumors has established this route of administration as practical and feasible. Identification of other receptors that are preferentially expressed on brain tumors, such as the interleukin-4 receptor, has resulted in the creation of a fusion protein against this receptor that contains a modified toxin from the bacteriaPseudomonas aeruginosa. This chimeric fusion toxin is currently under investigation in a Phase I clinical trial with patients with recurrent malignant astrocytoma, and other targeted toxins are under development for the treatment of these uniformly fatal tumors. Owing to these recent advances in targeted toxin therapy for malignant primary brain tumors, a review of the development of these agents for practicing neurosurgeons seems timely.

ISSN:0148-396X    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0148-396X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

OBJECTIVE:Transsphenoidal surgery for Cushing’s disease from a pituitary adenoma is an effective and safe treatment. Definitive preoperative diagnosis of Cushing’s disease caused by a pituitary adenoma is often difficult, particularly in patients with normal imaging studies and a normal sella turcica. We present the outcome of transsphenoidal surgery in patients with presumed Cushing’s disease and a normal pituitary magnetic resonance imaging scan.METHODS:Between January 1992 and December 1997, 105 patients underwent transsphenoidal surgery for Cushing’s disease at our institution. The criteria for inclusion in this study were clinical and biochemical studies strongly suggestive of Cushing’s disease, a normal magnetic resonance imaging scan with normal sella and sellar contents, no previous pituitary surgery, and transsphenoidal surgery performed at this institution. Eighteen patients fulfilled these criteria, and their results were analyzed retrospectively.RESULTS:The average age of the patients was 47.8 years; there were 13 women and 5 men. Inferior petrosal sinus sampling with and without corticotropin-releasing hormone stimulation was performed in 16 patients with correct localization of the lesion in 13 (81%). During surgery, the surgeon identified and removed 17 pituitary tumors; 15 patients had selective adenomectomies, one had a hemihypophysectomy, and two had total hypophysectomies. Thirteen discrete adrenocorticotropic hormone-secreting adenomas were proven histologically, and one pituitary gland had diffuse involvement with tumor. Complications occurred in five patients. Sixteen patients who were followed up for an average of 21.6 months had sustained remission, 12 of whom were profoundly hypocortisolemic immediately after surgery.CONCLUSION:In patients with Cushing’s disease and a normal magnetic resonance imaging scan, an experienced surgeon can perform transsphenoidal surgery resulting in effective removal of very small microadenomas, with clinical and biochemical remission in the majority. Inferior petrosal sinus sampling is helpful in localizing the adenoma.

ISSN:0148-396X    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0148-396X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

OBJECTIVE:The goals of this report were to outline the clinical presentation, radiological characteristics, surgical techniques, postoperative morbidity, and long-term follow-up results for cystic jugular foramen (JF) schwannomas and to describe their differences, compared with solid schwannomas involving the JF.METHODS:A retrospective analysis of radiological studies and surgical records identified five primarily cystic tumors among 21 cases of JF schwannomas that had been surgically treated at our institution.RESULTS:Two types of cystic JF schwannomas were observed, i.e., Type 1 lesions, which are single large cysts with thin ring-like enhancement of the tumor wall, and Type 2 lesions, which are multiple cysts with very irregular, thick enhancement of the cyst wall. The most common symptoms were hearing loss, ataxia, and headaches. Total surgical removal could be performed in all cases. The immediate postoperative findings indicated hearing improvement in three cases. No deterioration of lower cranial nerve function was observed. All patients were independent in the immediate postoperative period and in the long-term follow-up period (Karnofsky Performance Scale score, 90).CONCLUSION:Surgical treatment of cystic JF schwannomas can be very demanding because of generally stronger adhesion of the tumor capsule to the surrounding structures, fragile tumor capsules, and difficulty in identification of the arachnoidal planes in some cases. Early identification of the arachnoidal planes without opening of the cyst and sharp dissection may be useful. Careful intradural opening of the JF should be performed to achieve total removal of the last tumor portion within the JF. A comparison of these lesions with solid schwannomas involving the JF indicated that cystic tumors affected a younger population, with less preoperative swallowing impairment (P< 0.05). The immediate postoperative course in both types of cystic JF schwannomas was usually better than for solid lesions, because of minor postoperative cranial nerve morbidity, especially involving lower cranial nerve function, in the latter cases. Long-term follow-up data failed to demonstrate any significant differences in final patient outcomes, however.

ISSN:0148-396X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

OBJECTIVE:To evaluate the long-term outcome of a subtotally resected residual tumor and to assess its growth rate, we analyzed the records of 38 patients with residual petroclival meningioma.METHODS:Clinical records and radiological findings of 38 cases of petroclival meningioma that were diagnosed and subtotally resected at Seoul National University Hospital between 1981 and 1997 were carefully reviewed. Follow-up imaging studies were reviewed, and Karnofsky performance scale scores at the last follow-up were recorded. The duration of follow-up ranged from 6 to 141 months (mean, 47.5 mo; median, 30 mo). Tumor progression and progression-free survival rates were assessed. The growth rate of a residual tumor was evaluated by measuring the equivalent diameter and the tumor volume serially; the tumor doubling time was calculated, and the predictive factors for determining the growth pattern in residual tumors and the prognosis were analyzed.RESULTS:In 33 (87%) of the 38 patients, Karnofsky performance scale scores at the last follow-up were 80 or above. The median progression-free survival time among patients with subtotally resected tumors was 66 months, and the 5-year progression-free survival rate was 60%. The growth rate of residual tumors was low (volume increase, 4.94 cc/yr; diameter increase, 0.37 cm/yr). The mean tumor doubling time was 8 years. Although there were no significant predictive factors, age and extent of tumor resection seemed to influence the progression-free survival rate. Significant factors affecting the growth rate were age and occurrence of menopause.CONCLUSION:Subtotal resection with or without radiation or radiosurgery should be considered as a suitable treatment option for patients with petroclival meningiomas, especially the elderly, because the growth rate of residual tumors is low.

ISSN:0148-396X    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0148-396X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

OBJECTIVE:Between 1 and 6% of patients who are diagnosed with facial pain syndromes have tumors that involve the trigeminal nerve. We report the effects of stereotactic radiosurgery on tumor-related trigeminal pain.METHODS:We reviewed results, from a prospective database, for 24 consecutive patients with cranial base tumors and either trigeminal neuralgia (n = 9) or painful trigeminal neuropathy (n = 15) who underwent stereotactic radiosurgery during an 8-year period. The tumor was the radiosurgical target for these patients (not the trigeminal nerve or ganglion). The median clinical follow-up period after radiosurgery was 45 months (range, 12–90 mo); the median neuroimaging follow-up period was 36 months (range, 5–86 mo).RESULTS:There were 20 women and 3 men, with an average age of 57 years (range, 33–79 yr). One patient had bilateral facial pain and underwent staged radiosurgery. Pathological classification indicated 16 meningiomas and 8 malignant cranial base tumors (adenoid cystic carcinoma, n = 6; squamous cell carcinoma, n = 2). Twelve of 24 patients (50%) were initially free of pain, and another 11 patients (46%) reported that they experienced significant improvements in their trigeminal pain syndromes after radiosurgery. The tumor histological type, quality of facial pain, preexisting facial numbness, and marginal and maximal radiation doses were not related to postradiosurgical facial pain outcomes. Three patients with malignant cranial base carcinomas developed recurrent facial pain, 1 to 9 months after radiosurgery, which was related to tumor progression outside the irradiated volume. One patient (4%) developed new partial V2numbness after radiosurgery.CONCLUSION:Radiosurgery proved to be effective in improving tumor-related trigeminal pain for the majority of patients with either benign or malignant cranial base tumors. Recurrence of trigeminal pain is frequent for patients with malignant cranial base carcinomas and is related to tumor progression.

ISSN:0148-396X    

出版商:OVID    

年代:2000

数据来源: OVID