Gamma Knife radiosurgery: technology, applications, and future directions.

This article provides a general overview of Gamma Knife radiosurgery, with a brief history of the design of the unit and a review of radiosurgical procedures. The gamma unit itself is discussed, including its different elements and how they work. The clinical applications are then examined, such as treatment of arteriovenous malformations, acoustic schwannoma, meningiomas, pituitary adenomas, glial tumors, and others.

Late cyst convolution after gamma knife radiosurgery for cerebral arteriovenous malformations.

Although many series of patients with cerebral arteriovenous malformations (AVMs) treated radiosurgically have been published, there has been little information on cysts appearing several years after irradiation. Herein, we discuss the incidence, mechanisms and predictability of late cyst formation based on our personal experiences, as well as reported patients. The incidence of this complication, though generally considered to be 0.

Conservative management of acoustic neurinomas: prospective study of long-term changes in tumor volume and auditory function.

Recently reported retrospective analysis on the natural courses of acoustic neurinomas have disclosed that 26-86% of tumors show very slow, or no, growth for many years. To our knowledge, however, there have been no prospective analyses of the natural course of these tumors. We prospectively analyzed tumor growth as well as auditory function changes in 12 patients (13 tumors) managed conservatively.

Radiation-related adverse effects observed on neuro-imaging several years after radiosurgery for cerebral arteriovenous malformations.

Background: To our knowledge, there are no reported arteriovenous malformation (AVM) series in which detailed long-term follow-up results after radiosurgery were described based on the whole patient group.

Method: We performed a detailed long-term follow-up study of 53 patients with cerebral AVMs treated with gamma knife (GK) radiosurgery, with emphasis on radiation-related adverse effects detected on neuro-imaging after a long post-irradiation latency period (3-10 years). The post-GK follow-up period was 40-232 months excluding two mortalities, the mean being 112 and the median being 111 months.

A diffuse white matter ischemic lesion appearing 7 years after stereotactic radiosurgery for cerebral arteriovenous malformations: case report.

Objective And Importance: Little information is available about radiation-induced complications occurring more than 5 years after radiosurgical treatment for arteriovenous malformations.

Clinical Presentation: We present a patient with arteriovenous malformations who experienced hemimotor weakness caused by a diffuse white matter necrotic lesion developing 7 years after gamma knife radiosurgery. The original nidus had been too large (24.

Middle cerebral artery stenosis caused by relatively low-dose irradiation with stereotactic radiosurgery for cerebral arteriovenous malformations: case report.

Objective And Importance: There have been occasional reports of stenosis or occlusion of major cerebral arteries occurring several years after stereotactic radiosurgery for cerebral arteriovenous malformations. Nevertheless, little information is available regarding the actual irradiation dose to which the affected artery had been exposed.

Clinical Presentation: We present a patient with arteriovenous malformations who, although asymptomatic, developed remarkable stenosis of the middle cerebral artery trunk (M1) 3 years after gamma knife radiosurgery.

Tumor cell counting using an image analysis program for MIB-1 immunohistochemistry.

A cell counting method for MIB-1 immunohistochemistry, using an image analysis program, NIH Image, on a personal computer, has advantages over manual cell counting by microscopy. MIB-1 slides were photographed at a magnification of x 50 on 24 x 36 mm color films and the photographs were then enlarged to adequate size for observation. The MIB-1-positive cells, on the enlargements, were marked with a white pen, and negative cells with a black pen.

Spontaneous regression of primary intracranial germinoma. A case report.

Background: Testicular seminomas are well known to regress spontaneously at a higher incidence than other tumors. To date, there have been no reports of spontaneous regression of an intracranial germinoma, although these tumors are histologically identical to testicular seminomas.

Methods: The authors present a patient with a primary intracranial germinoma that regressed spontaneously.

MIB-1 staining index and peritumoral brain edema of meningiomas.

Background: Growth rates and tumor aggressiveness of meningiomas are thought to be closely related to brain edema development. However, histopathologic data alone are not consistently accurate predictors of the behavior and clinical course of a meningioma.

Methods: The authors examined 57 histologically proven intracranial meningiomas to identify factors, including growth fractions determined by MIB-1 immunostaining, that may influence the development of meningioma-associated peritumoral brain edema.

Perioperative antimicrobial prophylaxis in neurosurgery: clinical trial of systemic flomoxef administration and saline containing gentamicin for irrigation.

The efficacy of a new protocol consisting of a prophylactic antibiotic regimen of peri- and postoperative intravenous administration of flomoxef and irrigation of the operative field with saline containing gentamicin was assessed by comparing infection rates in two consecutive series of patients who underwent neurosurgical procedures. Group A received postoperative flomoxef administration, with saline containing no antibiotics for irrigation, from July 1988 to December 1989. Group B received the new protocol from January 1990 to December 1991.

Gamma knife radiosurgery for arteriovenous malformations: long-term follow-up results focusing on complications occurring more than 5 years after irradiation.

The detailed long-term follow-up results of 40 patients treated for cerebral arteriovenous malformations with gamma knife radiosurgery are presented, with special reference to postradiosurgical complications that can develop many years after irradiation. The follow-up period after radiosurgery was 54 to 205 months, excluding one mortality, with a mean and a median of 106 and 97 months, respectively. One patient (2.

Radiosurgery for acoustic neurinoma with rapid growth and relatively high staining indexes for proliferating cell nuclear antigen and MIB-1.

A 54-year-old female presented with a rapidly growing acoustic neurinoma. The tumor doubling time was 216 days or less before surgery and staining indexes for proliferating cell nuclear antigen (PCNA) and MIB-1 were relatively high (4.1% and 2.

Posterior cerebral artery aneurysm associated with unilateral internal carotid artery agenesis--Case report.

A 38-year-old housewife presented with a ruptured aneurysm associated with unilateral internal carotid artery agenesis. She had been in good health until May 31, 1994, when she was admitted to our facility immediately after sudden onset of headache and nausea. She was alert and exhibited no focal neurological deficit on admission.

Gamma knife radiosurgery for cerebral arteriovenous malformations: an autopsy report focusing on irradiation-induced changes observed in nidus-unrelated arteries.

Background: In radiosurgical treatment for an arteriovenous malformation (AVM), the effects of irradiation on the intranidal and perinidal angioarchitectures have seldom been analyzed histologically. An autopsy case is reported, studying an AVM treated by gamma knife radiosurgery. Postmortem studies following AVM-unrelated death were performed after a 2-year angiography had demonstrated complete nidus obliteration.

Meningioma associated with chronic subdural hematoma and meningothelial cell cluster within the hematoma capsule--case report.

A 47-year-old female presented with an unusual association of convexity meningioma with chronic subdural hematoma, manifesting as headache and left hemiparesis 10 days before admission. Computed tomography showed an isodense right frontal tumor with significant enhancement postcontrast and a hypodense subdural hematoma in the right frontotemporal area. Craniotomy exposed an extracerebral tumor facing a liquefied subdural hematoma encapsulated by outer and inner membranes.

Peritumoral brain edema and cortical damage by meningioma.

Forty supratentorial meningiomas were analyzed to identify factors causing peritumoral brain edema. Parasagittal, sphenoid ridge, and olfactory groove meningiomas induced edema more frequently than those in other locations. Meningothelial meningiomas were more invasive than other types and were associated with more peritumoral edema.

Postradiation volume changes in gamma unit-treated cerebral arteriovenous malformations.

Postradiation changes in angiographically determined nidus volume were quantitatively studied in 22 arteriovenous malformation (AVM) cases treated by gamma unit radiosurgery. The postradiosurgical decrease was statistically significant by post-treatment year 2 (p < .05).

Solitary pyogenic thalamic abscess--two case reports.

We report two patients with solitary thalamic abscesses, occurring among 91 consecutive patients (2.2%) with computed tomography (CT)-diagnosed and surgically-verified brain abscess experienced in our college during 1975 to 1991. A 9-year-old girl with congenital heart disease experienced frequent vomiting followed by left hemiparesis and deterioration of consciousness.

Asymptomatic calcified chronic subdural hematoma--report of three cases.

Three adults with asymptomatic calcified chronic subdural hematoma are described. Plain skull x-ray films following head trauma disclosed calcified chronic subdural hematomas and computed tomography (CT) revealed large, frontoparietal, calcified hematomas in all cases. A 49-year-old male received hematoma removal because of his lower age and CT evidence of cerebral compression.

Penetration of intravenous antibiotics into brain abscesses.

INTRA-ABSCESS CONCENTRATIONS OF the intravenously administered latamoxef (LMOX, moxalactam in the United States) and cefotetan (CTT), were studied in 11 patients with intracranial abscess. None of these patients underwent surgical ablation of the abscess. In all cases, the abscess was aspirated, and multiple aspirations were required in five patients.

Recurrence of symptomatic Rathke's cleft cyst: a case report.

A 65-year-old man presented with bitemporal hemianopsia. He had undergone frontal craniotomy for a Rathke's cleft cyst associated with narrowed visual field 8 years earlier. His vision had returned to normal soon after surgery and he remained asymptomatic until the present complaint.

Posttraumatic cerebral arterial spasm--case report.

Posttraumatic cerebral arterial spasm occurred in a 51-year-old male after a fall striking the left frontal region of the head. The initial computed tomography was identical to that of severe subarachnoid hemorrhage from ruptured aneurysm. He was neurologically stable for the 1st week following the accident, but his condition deteriorated rapidly, culminating in death due to severe delayed cerebral arterial spasm on the 15th day after injury.

Long-term follow-up of radiosurgically treated arteriovenous malformations in children: report of nine cases.

Long-term follow-up results of nine children treated for cerebral arteriovenous malformation with a gamma unit are presented. Complete nidus obliteration was angiographically confirmed in six cases and significant decreases in arteriovenous malformation size were observed in the other three. There were no radiation-related deteriorations in physical or mental development.