Conductivity of living intracranial tissues.

Resistivity values were measured from living human brain tissue in nine patients. A monopolar needle electrode was used with a measurement frequency of 50 kHz. Mean values were 3.51 Ohms m for grey matter and 3.91 Ohms m for white matter. Cerebrospiral fluid had a mean value of 0.80 Ohms m. Values for tumour tissues were dependent on the type of tumour and ranged from 2.30 to 9.70 Ohms m.

MR angiography with three-dimensional time-of-flight and targeted maximum-intensity-projection reconstructions in the follow-up of intracranial aneurysms embolized with Guglielmi detachable coils.

BACKGROUND AND PURPOSE: Intra-arterial contrast angiographies are generally used to confirm treatment results of endovascular neurointerventions such as aneurysm obliteration. We compared MR angiography with digital subtraction angiography (DSA) as a follow-up technique for the detection of aneurysmal remnant cavities and arterial patency in patients treated for intracranial aneurysms with Guglielmi detachable coils (GDCs). METHODS: In 20 consecutive patients, follow-up MR angiography and routine intra-arterial cerebral angiography were performed on the same day 1 to 7 months (mean, 4.5 months) after embolization with GDCs. MR angiographic data were postprocessed for subvolume maximum intensity projections centered on the region of the treated aneurysm. Hard copies of both imaging studies were interpreted independently in a blinded fashion to record and compare remnant cavities, location of residual flow, and adjacent arterial narrowing, using DSA as the standard of reference. The interpreters also established an occlusion grade for the treated aneurysms as evidenced on DSA images and evaluated MR angiograms for artifactual effects. RESULTS: Overall sensitivity and positive predictive value of MR angiography in revealing aneurysmal remnant cavities were both 90%. Specificity in ruling out a remnant cavity with MR angiography was 91%. One remnant cavity was missed by MR angiography, and in five patients, false adjacent arterial encroachments were reported. CONCLUSION: MR angiography may be useful in the long-term follow-up of successfully treated small and medium-sized aneurysms after concurrent primary verification of their occlusion with DSA.

Patient outcome after endovascular treatment of intracranial aneurysms with reference to microsurgical clipping.

OBJECTIVES: Endovascular treatment of intracranial aneurysms with Guglielmi detachable coils (GDC) has found growing acceptance worldwide, and partially replaced conventional microsurgery. In this study clinical and angiographical results of embolization are reviewed. In addition, long-term neuropsychological patient outcome with reference to surgery is assessed. Indications for screening and follow-up of the patients as limitations and recent achievements of aneurysm embolization are discussed. MATERIAL AND METHODS: Angiographical and clinical follow-up of the first 44 patients with 48 GDC-coiled aneurysms are reviewed. Postprocedural clinical, emotional and social (CES) outcome on disability scale as scored from postal questionnaire data is presented and compared to 106 currently operated patients. RESULTS: In 75% of the embolized aneurysms successful occlusion was achieved, procedural mortality was 2.3% and morbidity 18.2%. Clinical status of all 15 patients with unruptured aneurysms preserved. Of the surviving 29 patients with ruptured aneurysms 12 improved and the rest preserved their clinical status. In 91% of the embolized patients and in 85% of the operated patients CES outcome was categorized as good or excellent. The difference was statistically nonsignificant. CONCLUSION: Embolization with GDC is a feasible, effective and safe mini-invasive method in small aneurysms with a small neck. However, intentional parent artery occlusion, novel endovascular techniques and embolic agents or supplementary surgery may be necessary in selected cases. Neuropsychological long-term outcome of the patients treated for an intracranial aneurysm does not differ much between GDC embolization and microsurgical clipping.

Endovascular treatment of carotid-cavernous fistulae.

INTRODUCTION: In the embolotherapy for the treatment of carotid-cavernous fistulae (CCF) several embolic agents and techniques have been reported. In this series the efficiency of transarterial electrothrombosis with Guglielmi detachable coils (GDC) in direct fistulae and the occlusion with particles, tissue glue and platinum coils in indirect fistulae is studied and the implications of these findings is discussed regarding classification, conservative therapy and follow-up. MATERIAL AND METHODS: Eleven consecutive patients were reviewed retrospectively. Four patients had direct high flow fistulae from the internal carotid arteries and the rest had low flow dural fistulae. Postprocedural clinical outcome and angiographical follow-up are presented. RESULTS: Six patients became symptom free, in 4 patients the symptoms resolved and 1 patient suffered a minor procedural complication. In the 8 follow-up angiographies the fistulae of 7 patients were totally closed, including the 4 patients with direct fistulae. CONCLUSION: Progressive clinical manifestations require embolization to alleviate the symptoms and to prevent further complications of the arteriovenous shunting. Embolization with GDC is a feasible, effective and safe method in direct fistulae.

Interstitial chemotherapy with carmustine-loaded polymers for high-grade gliomas: a randomized double-blind study.

OBJECTIVE: To find out the effect of carmustine (bischloroethyl-nitrosourea) combined with a biodegradable polymer in the treatment of malignant (Grades III and IV) gliomas, applied locally, at the time of the primary operation. METHODS: Prospective, randomized double-blind study of an active treatment group versus a placebo group. Conducted at the Departments of Neurosurgery of the University Hospitals of Helsinki, Tampere, and Turku in Finland and Trondheim in Norway. The study consisted of 32 patients (16 in each treatment group) enrolled between March 23, 1992, and March 19, 1993. The study was planned to include 100 patients but had to be terminated prematurely, because the drug that was being used had become unobtainable. The main outcome measures included the survival times of patients after the operations and the application of an active drug or placebo. RESULTS: The median time from surgery to death was 58.1 weeks for the active treatment group versus 39.9 weeks for the placebo group (P = 0.012). For 27 patients with Grade IV tumors, the corresponding times were 39.9 weeks for the placebo group and 53.3 weeks for the active treatment group (P = 0.008). At the end of the study, six patients were still alive, five of whom belonged to the active treatment group. CONCLUSION: Carmustine applied locally in a biodegradable polymer at the time of primary operation, seems to have a favorable effect on the life span of patients with high-grade gliomas.

Transarterial embolization of a direct carotid cavernous fistula with Guglielmi detachable coils.

Four patients underwent transarterial embolization of a carotid-cavernous fistula with Guglielmi detachable coils; in three cases as the initial form of treatment and in one case after treatment via transarterial balloon embolization failed. The fistulas were 2 to 3 mm in diameter on pretreatment angiograms. Complete obliteration was achieved in two patients; in the other two, minimal residual flow remained immediately after embolization but disappeared by follow-up angiography. One to four coils were used to occlude the fistulas. The internal carotid artery remained patent in all patients, and there were no complications.

Diagnosis and embolizing of spinal arteriovenous malformations.

Spinal arteriovenous malformations are uncommon disorders associated with considerable difficulty in diagnosis and treatment. They are divided into dural arteriovenous fistulas and intradural medullary spinal cord angiomas. In this retrospective series of six patients the clinical outcome of embolization is presented. The patient material consisted of three dural fistulas and three cord angiomas, one of which bled causing sudden paresis, pain and incontinence. In the remaining five patients the symptoms were progressive consisting of paraesthaesias, paraparesis, pain and incontinence. The clinical status of four patients was not changed after the treatment, one deterioriated and one improved. There were no bleedings after the therapy. In one patient spinal angiography for follow-up was performed and recanalization was seen in the dural fistula after particle embolization. Also, in one cord angioma embolized with particles reflow appeared in the immediately repeated angiography. For permanent angioma occlusion tissue adhesive is preferred as embolic material. Surgical therapy as an alternative or adjuvant to embolization is discussed with a review of the literature. Early timing of the therapeutic intervention is stressed to avoid the development of irreversible ischaemic medullopathy and to prevent haemorrhage. The therapeutic procedures at the early stage of the disease may be curable or, at least, halt the progression of the symptoms. Cross-sectional imaging studies and myelographies may reveal the lesion. For the definitive diagnosis of spinal angioma with its vascular feeders and for the evaluation of its occlusion grade after the therapy selective spinal angiography is needed.

The site of impulse generation in transcranial magnetic stimulation of the facial nerve.

The facial nerve can be stimulated in its intracranial course through transcranial magnetic stimulation (TMS). We studied the site of impulse generation produced by TMS by comparing the latencies of the muscle evoked potentials (MEPs) elicited with TMS and intracranial electrical stimulation (IES) of the facial nerve during neurosurgical posterior fossa procedures. In a series of 25 patients, the mean latency of the TMS elicited MEPs, recorded in the orbicularis oris muscle, was 5.0 ms (SD 0.58). Also IES of the distal part of the facial nerve in the internal acoustic meatus showed a mean latency of 5.0 ms (SD 0.68). Proximal IES in the root entry zone of the facial nerve, and intermediate IES between root entry zone and meatus, produced MEPs with significantly longer latencies compared to TMS and distal IES (p < 0.05). The findings suggest that the TMS induced facial nerve activation, leading to a MEP response, takes place within the internal acoustic meatus.

The treatment of spontaneous intracerebral hemorrhage. A prospective randomized trial of surgical and conservative treatment.

In a prospective study, 52 patients with a spontaneous supratentorial intracerebral hematoma (ICH) were randomly assigned to receive emergency surgery or conservative treatment within 48 hours after the bleed. Patients with a decreased level of consciousness and/or a severe neurological deficit were admitted to the study. The overall mortality rate at 6 months was 42%: 10 (38%) of the 26 patients in the conservative group and 12 (46%) of the 26 in the surgical group. Six (20%) of the 30 survivors at 6 months were able to conduct their activities of daily living independently: five (31%) of the 16 patients in the conservative group and one (7%) of the 14 in the operative group. These differences are not statistically significant. The mortality rate of semicomatose or stuporous patients (Glasgow Coma Scale score 7 to 10) was statistically significantly lower in the surgical group (none of the four patients) than in the conservative group (four of five patients) (p less than 0.05); however, all surviving patients in this subgroup were severely disabled. The study suggests that surgical treatment of this category of patients with ICH does not offer any definite advantage over conservative treatment. In semicomatose or stuporous patients, surgery may improve the length of survival, but the quality of life remains poor.

Stress/catecholamine-induced cardiac necrosis. Reduction by beta 1-selective blockade.

Catecholamine-induced cardiac necrosis is a well-described phenomenon. Patients with severe head injury are known to be in a marked hyperadrenergic state and can experience cardiac morbidity; this was confirmed in a pilot study. A further study was then undertaken to examine a possible relationship between plasma catecholamine concentration and cardiac morbidity in patients with severe head injury and to assess the effect of intervention with the beta 1-selective agent atenolol. The study involved 114 hemodynamically stable patients with acute head injury who were randomized, double blind, to either placebo or atenolol given intravenously (10 mg every six hours) for three days and then orally (100 mg once a day) for four days. Both groups were equally stressed in terms of raised arterial norepinephrine levels. In patients receiving placebo, but not in those given atenolol, there was a significant (P less than 0.01) positive correlation between arterial level of norepinephrine and plasma level of cardiac-specific isoenzyme CK-MB. Thirty percent of the placebo group, in contrast to 7.4% of the atenolol group (P less than 0.05), had pathologically elevated CK-MB levels (ie, greater than 3% of total CK, a value compatible with acute myocardial infarction). Atenolol appeared to significantly reduce the likelihood of supraventricular tachycardia and ST-segment and T-wave changes and prevented cardiac necrosis (as determined post mortem). The finding that beta 1-selective blockade significantly inhibits catecholamine-induced necrosis has possible broad clinical implications.

Acute surgery for intracerebral haematomas caused by rupture of an intracranial arterial aneurysm. A prospective randomized study.

In a randomized prospective study, 15 patients with an intracerebral haematoma caused by an intracranial aneurysm were treated concervatively and 15 operated on as an emergency. Mortality was 12/15 (80%) in the conservative group and 4/15 (27%) in the surgical group. The difference is statistically significant. The deaths in the conservative group were caused by both the primary haematoma and rebleeding. The results suggest that intracerebral haematomas caused by rupture of an intracranial aneurysm should be evacuated immediately, and that the aneurysm should be clipped at the same operation.

Reduction of stress/catecholamine-induced cardiac necrosis by beta 1-selective blockade.

114 haemodynamically stable patients with acute head injury were randomised, double-blind, to either placebo or atenolol given intravenously (10 mg every 6 h) for 3 days then orally (100 mg daily) for a further 4 days. Both groups were equally stressed as shown by raised arterial noradrenaline levels. In patients receiving placebo, but not in those receiving atenolol, there was a significant (p less than 0.01) positive correlation between arterial noradrenaline and levels of the myocardial isoenzyme of creatine kinase (CKMB). 30% of the placebo group compared with 7.4% of the atenolol group (p less than 0.05) showed CKMB levels greater than 3% of total creatine kinase (compatible with myocardial damage). CKMB levels greater than 6% of total creatine kinase (compatible with acute myocardial infarction) were present in 16.7% of patients receiving placebo but in no patients receiving atenolol (p = 0.053). Atenolol appeared to reduce significantly the likelihood of supraventricular tachycardia and ST-segment and T-wave changes and prevented cardiac necrosis seen at necropsy.

Estrogen and progestin receptors in intracranial tumors.

Tissue samples from 17 intracranial tumors were analysed for the cytosolic estrogen and progestin receptor concentration. Three of the four meningiomas were progestin receptor-positive, but all were estrogen receptor-negative. All the four meningioma patients were postmenopausal women. The intracranial metastasis of a mammary carcinoma contained both estrogen and progestin receptors. Low progestin receptor concentration was found in an astrocytoma of a postmenopausal women. In addition, the presence of estrogen and progestin receptors was studied in four prolactinomas, two glioblastomas, two oligodendrogliomas, two mixed-cell carcinomas and one astrocytoma. All these tumors were estrogen and progestin receptor-negative.