Seizures and Brain Arterovenous Malformation: A Surgical Series.

Seizures are common symptoms of supratentorial arteriovenous malformations (AVMs). The potential risk factors for epilepsy in patients with AVMs are still controversial. The reported long-term outcome of seizures after surgical treatment of AVMs is variable and the data available are mainly from small retrospective case series.We identified all consecutive patients between 1990 and 2006 who underwent microsurgical resection of supratentorial AVMs at our institute. Pre-operative risk factors for seizures, intra-operative characteristics, long-term neurological disability, and seizure outcome (Engel's classification) were recorded and analyzed.During the study period, 110 patients underwent surgical resection of supratentorial AVM. Sixty of them (55 %) were symptomatic for seizures preoperatively. In our series, the absence of preoperative neurological deficits (p = 0.005), a large AVM size (p = 0.005), and no history of preoperative AVM hemorrhage (p < 0.001) were identified as risk factors for preoperative seizures. Following surgical resection, 77 % of patients with preoperative seizures had a modified Engel class I outcome. Among patients without a history of preoperative epilepsy, 56 % had new-onset seizures after surgical resection. None of the risk factors associated with preoperative seizures was associated with post-operative seizures. As there are no reliable factors predicting patients who may benefit from surgical treatment, epilepsy control should not be considered as the primary goal of AVMs surgery.

Surgical exclusion of unruptured middle cerebral artery aneurysms: experience of 126 cases.

A group of 126 surgical patients with 143 unruptured MCA aneurysms was evaluated in order to determine the risks of treatment and possible adjuncts for safer surgery. The precise location and size of the aneurysms were determined in each case; 21 aneurysms were located on the M1 tract, 109 on the main division - which consisted of more than two branches in 10 cases and was proximally located in 12 cases - and 13 were distal; 36 aneurysms were small (<7 mm), 90 standard, and 17 large or giant (>15 mm); 45 patients harbored multiple aneurysms (12 on the ipsilateral MCA). The aneurysms were excluded by clip in most cases, with the assistance of intraoperative flowmetry in 78 patients. Temporary proximal vessel occlusion was used in 57 patients (>10 min in 8 cases), without significant effects on radiological or clinical outcome. After surgery, newly occurring minor deficits were observed in 5 patients and significant deficits in 4; one patient died from an intractable coagulopathy. The low rate (3.9 %) of unfavorable results (modified Rankin Score > 2) linked to surgery justifies serious consideration for treatment in these patients, especially when facing the high disability rate after the rupture of aneurysms in this anatomical location.

Results of surgery for cavernomas in critical supratentorial areas.

A total of 121 patients surgically treated between 1991 and 2011 for cavernomas in critical supratentorial areas were evaluated. Anatomical location, size and the possible association with developmental venous anomalies (DVA) were assessed in each case: 43 cavernomas were in the speech area, 39 were rolandic (or peri-rolandic), 14 insular, 10 nuclear, 9 calcarine and 6 ventricular. In 49 % of the cases, the cavernoma was <1.5 cm; in 6 patients, radiological growth was documented. A method of intraoperative localization was adopted in 78 cases: B-mode echography or a stereotactic guide in 22 cases, and a neuronavigation system in 56 cases; preoperative angiography was done in 22 cases. Early postoperative epilepsy (within 7 days of surgery) was observed in 15 cases. As for clinical outcome, 14 patients presented with mild symptoms (modified Rankin Scale 1-2); significant deficits occurred ex-novo in 5 patients. The presence of epilepsy at follow-up was assessed through the Maraire Scale: 44 % of patients presenting with epilepsy were free of seizures and without therapy at a mean follow-up of 4.6 years, and an additional 55 % had complete control of seizures with therapy. It is concluded that surgery is indicated in the management of cavernomas in critical supratentorial locations, with a caveat for insula and especially basal ganglia.

Surgery after embolization of cerebral arterio-venous malformation: experience of 123 cases.

A group of 123 patients with large or critically located arterio-venous malformations (AVMs), operated on between 1990 and 2011 and who underwent preoperative embolization, was assessed in order to clarify the risks of this combined treatment. AVM location, volume, and Spetzler's grade were assessed in each case; AVM volume was over 20 cm(3) in 49 % of the cases; Spetzler's grade was 3 or above in 76 % of the cases (with 34 cases in grades 4-5). A mean of 2.3 embolization procedures per patient were carried out, using bucrylate and, more recently, Onyx and/or Glubran; a 4.5 % procedure-related complication rate was observed. Complications occurring after surgery were classified as hemorrhagic (16 cases, 8 requiring surgical evacuation) or ischemic (4 cases); hemorrhagic complications were more common for AVMs with volumes >20 cm(3) and/or deep feeders. Surgery-related unfavorable results (modified Rankin Score > 2) were observed in 6 % of patients in Spetzler's grade 3, and in 20-25 % of patients in grades 4-5. More recently, a triple treatment (radiosurgery + embolization + surgery) allowed for obtaining favorable results (mRS 0-2) in all patients. It has been concluded that a combined treatment with embolization and surgery constitutes a reasonable choice for complex cerebral AVMs; the association of radiosurgery may improve the patients outcome.

The role of constitutive and inducible nitric oxide synthase in the human brain after subarachnoid hemorrhage.

AIM: Results of prior experimental studies show that nitric oxide (NO) plays an important role in the pathogenesis of vasospasm. In the present study, the expression of endothelial NO synthase (eNOS), neuronal NO synthase (nNOS) and of inducible NO synthase (iNOS) in the human brain after subarachnoid haemorrhage were studied. METHODS: Twenty-three samples of gyrus rectus or temporal operculum that were obtained during a surgical approach to anterior circulation aneurysms were used for this study. Seven samples were obtained during surgery from patients who underwent operation for unruptured aneurysms (control group). eNOS-mRNA, nNOS-mRNA and iNOS-mRNA were extracted and amplified by RT-PCR. Patients were subdivided for intergroup comparison by: age < 60 / > 60 years; source of sample; clinical grading; extent of subarachnoid clot; presence of intracerebral/intraventricular hematoma; surgical timing; vasospasm; outcome. RESULTS: There was a significant increase in the expression of eNOS between SAH and control groups (P=0.046); eNOS hyperexpression was higher in the patients in poor clinical conditions (P=0.002) and lasted until the late phase of haemorrhage. nNOS overall expression was unchanged but hyperexpression was observed in the patients in poor clinical conditions (P=0.008). There was a significant hyperexpression of iNOS in SAH group (P=0.026), and in patients with vasospasm (P=0.0024); the expression was significantly reduced in the late phase of haemorrhage (P=0.0038). CONCLUSIONS: The acute decrease of NO after SAH is not determined by reduced constitutive NOS expression and iNOS induction is a consequence of SAH and plays a major role in the pathogenesis of vasospasm.

Shape recovery and volume calculation from biplane angiography in the stereotactic radiosurgical treatment of arteriovenous malformations.

PURPOSE: A model for calculating the three-dimensional volume of arteriovenous malformations from biplane angiography. METHODS AND MATERIAL: Three-dimensional (3D) volume reconstruction is easily feasible with axial, coronal, or sagittal computer tomography (CT) and nuclear magnetic resonance (NMR) scans. On the other hand, radiosurgical treatment of arteriovenous malformations (AVM) is exclusively based on two orthogonal stereotactic projections, obtained with angiographic procedures. Most commonly, AVM volumes have been calculated by assimilating the nidus volume to a prolate ellipsoid. We present an algorithm dedicated to 3D structure reconstruction starting from two orthogonal stereotactic projections. This has been achieved using a heuristic approach, which has been widely adopted in the artificial intelligence domain. RESULTS: Tests on phantom of different complexity have shown excellent results. CONCLUSION: The importance of the algorithm is considerable. As a matter of fact: (a) it allows calculations of complex structures far away from regular ellipsoid; (b) it permits shape recovery; (c) it provides AVM visualization on axial planes.

Preoperative embolization of arteriovenous malformations with polylene threads: techniques with wing microcatheter and pathologic results.

The technique with a wing microcatheter system and the pathologic aspects of 11 cerebral arteriovenous malformations (AVMs) surgically resected after embolization with polylene threads are reported. Embolization was performed once in eight patients and twice in three patients. Resected AVMs were submitted both to routine hematoxylineosin examination and to immunohistochemical workup in order to detect the type of immunologic response to thread emboli. In nine cases, 50% or more of the nidus was obliterated by the embolization. After embolization two patients developed reversible neurologic deficits. Pathologic specimens of resected AVMs demonstrated no vascular necrosis; however, a moderate inflammatory response could be seen, characterized by the presence of both mononuclear cells and foreign-body giant cells, associated with the absence of polymorphonuclear infiltrates. A granulomatous fibrotic process was identified that was present from the first month after embolization. Immunohistochemistry indicated that the immunologic response to thread emboli was cell-mediated, not humoral. Embolization with the wing microcatheter with the use of polylene threads proved to be a safe and efficient system of embolization, as a preoperative procedure. Polylene threads are a nontoxic and biocompatible material that can be used as an embolic agent for brain AVMs.

Hemodynamic effects of preoperative embolization in cerebral arteriovenous malformations: evaluation with transcranial Doppler sonography.

A series of 83 patients with cerebral arteriovenous malformations is presented. All patients were evaluated with transcranial Doppler sonography. Thirty-two patients were treated with staged embolization and surgery: 19 of these patients were operated on within 4 weeks of the last embolization, and the remaining 13 patients underwent surgery 6 months or more from embolization. Transcranial Doppler sonography performed 1 day after embolization showed a significant (> 60%) reduction of main feeder flow velocity in 72% of patients after the first embolization and in 45% of patients after the second embolization. In no case did such a significant reduction occur after the third embolization. A flow redistribution in the basal vessels (defined as an increase in flow velocity of at least 30% of the initial value) occurred only in patients after the first embolization (64%). On delayed post-embolization studies, complete recovery of flow velocity in the embolized vessel occurred in 46% of patients, and sonographic recruitment of new feeders occurred in the remaining 54%. When main feeder flow velocity (mean) was higher than 120 cm/s after embolization and before surgery, the incidence of postoperative hyperemic complications (cerebral edema and/or intracerebral hematoma) was significantly higher than in patients with a mean flow velocity under 120 cm/s. It is concluded that transcranial Doppler sonography is a valuable method for a noninvasive hemodynamic assessment of shunt flow in arteriovenous malformations, and it permits a physiological monitoring of hemodynamic changes after embolization and allows more precise indications regarding further stages of embolization and timing of surgery after embolization.

Effect of nicardipine on basilar artery vasoactive responses after subarachnoid hemorrhage.

The effect of the dihydropyridine calcium antagonist, nicardipine, on the vasoactive responses of the basilar artery was investigated after subarachnoid hemorrhage (SAH). Forty-five rabbits were separated into one control group and four groups receiving SAH (nine animals each). The SAH was induced by injecting 5 ml of autologous arterial blood into the cisterna magna. SAH animals were subjected to one of the following: 1) no treatment; 2) intravenous (i.v.) saline infusion (vehicle); 3) i.v. infusion of low-dose nicardipine (0.01 mg/kg/hr), or 4) i.v. infusion of high-dose nicardipine (0.15 mg/kg/hr). The i.v. infusions were started immediately after SAH and continued for 48 hours. Serotonin (5-HT) (10(-8) to 10(-5) mol/L) was used to evoke dose-dependent vasoconstriction of isolated rings of the basilar artery 2 days after SAH. Acetylcholine (ACh) (10(-8) to 10(-4)) and adenosine-triphosphate (ATP) (10(-8) to 10(-4) mol/L) were applied after maximal contraction with 5-HT, evoke a dose-dependent vasodilatation. Compared with controls, in animals subjected to SAH serotonin caused similar or slightly larger contractions; nicardipine infusion did not decrease the amount of contraction observed after SAH. ACh and ATP caused significantly less dilatation in animals submitted to SAH than in controls. After high-dose nicardipine, ACh- and ATP-induced dilatations were significantly more pronounced (57% and 68% of initial contractile tone) than in the other animals receiving SAH (36%-39% and 45%-55%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Role of computed tomography in the management of vasospasm after subarachnoid hemorrhage.

The role of computed tomography (CT) in the management of vasospasm from subarachnoid hemorrhage was evaluated in 242 consecutive cases with CT performed within 7 days after hemorrhage. Only 20% of these cases did not show a detectable subarachnoid hemorrhage on CT. Subsequent angiograms showed vessel narrowing in 56% of the cases; associated clinical deterioration was noted in 34% of the cases. On later CT, clear ischemic areas were detected in 20% of the cases. A strict correlation between the amount of cisternal blood and the subsequent development of vasospasm was observed: although absent or thin cisternal depositions were rarely associated with vasospasm, consistent or thick depositions were frequently linked to vasospasm (72% of the cases) and to ischemic disturbances (51% of the cases), as well as to clear ischemic areas on later CT (30% of the cases). Regarding the morphology of the cisternal blood collection, the risk of developing vasospasm was at its lowest (42%) for depositions only in the frontal interhemispheric fissure and was at its highest (79%) for depositions in multiple cisterns. The site of cisternal deposition corresponded closely to the area of ischemia on later CT. The persistence of subarachnoid blood more than 72 hours after hemorrhage probably increases the risk of vasospasm, although our data are not conclusive. The definition of a CT scan "at risk" for vasospasm--based on the previous findings--gives practical advantages: proper selection of patients in regard to timing of operation, closer observation and the possibility of prophylactic treatment in patients "at risk," and more adequate evaluation of different therapeutic modalities for vasospasm. With regard to the last point, the incidence of vasospasm was not statistically different between two groups of patients uniformly "at risk": the first group submitted to early operation and the second awaiting operation.

The relevance of anatomic and hemodynamic factors to a classification of cerebral arteriovenous malformations.

Potential prognostic anatomic and hemodynamic factors were evaluated in 248 patients with cerebral arteriovenous malformations (AVMs), all treated by direct microsurgical removal. The size of each AVM was calculated by its volume, obtained by the multiplication of the three AVM diameters by 0.52. A surgical classification of AVM location (in 11 groups) is proposed. Types of feeders and of drainage were classified as superficial or deep; the extent of the drainage system was classified according to a four-degree scale. The mean flow velocity in the main AVM feeder, detected using transcranial Doppler ultrasonography, was used as an indirect measure of AVM shunt flow in a small number of patients (n = 29). AVM volume was a very important prognostic factor: the incidence of hyperemic complications and the morbidity and mortality rate were significantly higher when the volume of the lesion was greater than 20 cm3 (P less than 0.0001 for hyperemic complications; P less than 0.001 for permanent morbidity and mortality). The incidence of hyperemic complications and the morbidity rate were higher in AVMs in rolandic, inferior limbic, and insular locations than in AVMs in other locations. As for other anatomic factors: a) the presence of deep feeders significantly increased the incidence of hyperemic complications, as well as the morbidity and mortality rate; b) the presence of deep drainage significantly increased permanent morbidity only; c) the extension of the venous system was significantly related to the development of hyperemic complications, and to morbidity and mortality. Transcranial Doppler examination showed that mean flow velocities greater than 120 cm/s in the main feeder were associated with a significantly higher rate of postoperative hematomas and transient deficits. A classification of cerebral AVMs that takes into account AVM volume and location, the type of feeders, the extent of the drainage system, and the main feeder flow velocity is suggested.

Treatment of cerebral arteriovenous malformations with a combination of preoperative embolization and surgery.

Forty-nine patients with cerebral arteriovenous malformations (AVMs) were treated with preoperative embolization followed by resection using a microsurgical approach. In 27 patients, the AVM was located in an eloquent area; in 32 patients, the volume of the AVM was over 20 cm3. Preoperatively, flow-directed embolization was performed in 10 patients (28 procedures), selective embolization with threads was performed in 35 patients (46 procedures), and a combination of flow-directed and selective embolization was performed in 4 patients (12 procedures). The percentage of reduction of the AVM volume averaged 36% after embolization. Five minor complications (transient neurological deficits, in 2 cases associated with ischemic areas on the CT scan) were observed after embolization. The interval between the last embolization and surgery was as follows: within 10 days in 7 patients; between 11 and 20 days in 3 patients; between 21 and 30 days in 10 patients; between 31 and 60 days in 11 patients; and 2 months later in 18 patients. The efficacy of this combined treatment (embolization plus surgery) was evaluated by the incidence of hyperemic complications and the clinical outcome. Hyperemic complications occurred more frequently in patients with an AVM volume greater than 20 cm3. When compared with flow-directed embolization, selective embolization was linked with decreased bleeding during surgery; postoperatively, the incidence of cerebral edema was also lower. Clinical outcome was better after selective embolization, with no occurrence of major deficits and no mortality. When the percentage of reduction of the AVM volume after embolization was 40% or more, the incidence of intraoperative hyperemic complications was lower; moreover, new permanent deficits were never observed in patients with this volume reduction. A retrospective clinical comparison of two groups of patients with similar AVM volumes (greater than 20 cm3)--those given combined treatment (n = 32) versus those treated by direct surgery alone (n = 27)--showed that intraoperative bleeding appeared to decrease in patients treated by embolization; the incidence of postoperative hyperemic complications was not different in the two groups. New major deficits and deaths were less frequent in patients treated by embolization (P = 0.05 for the incidence of major deficits); postoperative epilepsy was also less common in these patients. In conclusion, combined treatment with selective preoperative embolization and direct surgery may help the neurosurgeon in the treatment of large, high-flow AVMs, reducing the risks connected with their surgical removal.

The effect of nicardipine on vasospasm in rabbit basilar artery after subarachnoid hemorrhage.

This study was performed to examine the effect of the dihydropyridine calcium antagonist, nicardipine, on vasospasm after experimental subarachnoid hemorrhage (SAH) in the rabbit. The study was carried out in two parts: 1) effect of intravenous nicardipine (n = 45) and 2) effect of intracisternal nicardipine (n = 21). SAH was induced by injecting 5 ml of autologous arterial blood into the cisterna magna. In the intravenous study, there were five groups: 1) SAH without treatment; 2) SAH with vehicle (saline); 3) SAH and intravenous infusion of low-dose nicardipine (0.01 mg/kg/h); 4) SAH and intravenous infusion of high-dose nicardipine (0.15 mg/kg/h); and 5) controls without SAH. The intravenous infusions were started immediately after SAH and continued for 48 hours until death. In the intracisternal study, there were three groups: 1) SAH without treatment; 2) SAH with intracisternal administration of nicardipine (0.37 mg/h); and 3) controls without SAH. Intracisternal infusions were begun 70 hours after SAH and continued for 2 hours until death. After perfusion-fixation, the basilar artery was removed and processed for morphometric analysis. In the intravenous study, vessels from animals subjected to SAH were significantly narrowed when compared with controls, although after high-dose nicardipine vessel caliber was slightly larger than in the other SAH groups. Animals given intracisternal nicardipine showed a nonsignificant reduction of caliber as compared with controls: only 12% decrease in diameter and 22% decrease in luminal area. In the rabbit SAH model, nicardipine had a very modest effect on vasospasm at the doses tested.

Cerebral vasospasm after head injury.

Cerebral vasospasm occurs frequently after head injury. Correlation between neurological deterioration and vasospasm has been reported previously, but delayed neurological deterioration secondary to vasospasm in head injury is a rare occurrence. We report the case of a 57-year-old man who, after a motorcycle accident, developed an acute subdural hematoma and a thick subarachnoid deposition of blood in the left sylvian-insular cistern. After surgical evacuation of the hematoma, the patient improved until the 10th postoperative day, when he developed aphasia and a right hemiparesis. Angiography demonstrated multitapering spasm, and a computed tomographic (CT) scan showed persistence of the cisternal deposition of blood. Despite therapy with hypervolemia, the patient improved only slightly. The association of head injury with substantial subarachnoid hemorrhage producing vasospasm has been considered rarely. Delayed posttraumatic vasospasm secondary to blood degradation products seems to play some role in the vasospasm after head injury. CT scanning may be useful in predicting vasospasm in such patients, and digital subtraction angiography might be useful in demonstrating it.

Oxidative stress in the human brain after subarachnoid hemorrhage.

OBJECT: The aim of this study was to verify the patterns of antioxidant enzymatic activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the human brain after subarachnoid hemorrhage (SAH) to verify whether an "oxidative stress situation" characterizes the brain response to subarachnoid bleeding. METHODS: Forty samples of gyrus rectus or temporal operculum that were obtained during a surgical approach to anterior circulation aneurysms were used for this study. The activity of total SOD, GSH-Px, and the SOD/GSH/Px ratio (which expresses the balance between the production of hydrogen peroxides by dismutation of superoxide radicals and the scavenging potential) were calculated in each case. Twelve samples were obtained from patients who underwent surgery for unruptured aneurysms (control group); 13 samples were obtained during surgical procedures performed within 72 hours of SAH; and 15 samples were obtained during delayed surgical procedures (> 10 days post-SAH). Ten patients presented with clinical deterioration caused by arterial vasospasm. In both SAH groups, the mean total SOD activity was significantly higher than in the control group (p=0.029). The mean activity of GSH-Px did not differ significantly between the SAH and control groups (p=0.731). There was a significant increase in the SOD/GSH-Px ratio in both SAH groups, as compared with controls (p < 0.05). There was a significant correlation between the enzymatic activity and the clinical severity of the hemorrhage, with findings of lower values of SOD and, mainly, of the SOD/GSH-Px ratio in the poor-grade patients. The SOD/GSH-Px ratio was 2.14+/-0.44 in patients who presented with clinical vasospasm and 1.24+/-0.2 in cases without vasospasm. CONCLUSIONS: The results of this study show an imbalance of the antioxidant enzymatic activities in the human brain after SAH. which is linked to the severity of the initial bleeding and possibly modified by the development of arterial vasospasm.

Double-blind, randomized, vehicle-controlled study of high-dose tirilazad mesylate in women with aneurysmal subarachnoid hemorrhage. Part I. A cooperative study in Europe, Australia, New Zealand, and South Africa.

OBJECT: Findings from previous multicenter clinical trials have suggested that tirilazad mesylate, a synthetic nonhormonal 21-aminosteroid, might be effective in preventing delayed cerebral ischemia following subarachnoid hemorrhage (SAH). This beneficial effect, however, was greater in males than females, possibly because of gender-related pharmacokinetic differences. The authors sought to assess the effects of administering a larger dose of tirilazad in women with SAH. METHODS: To test the efficacy of a higher tirilazad mesylate dose in female patients, a prospective randomized, double-blind, vehicle-controlled trial was conducted at 56 neurosurgical centers in Europe, Australia, New Zealand, and South Africa. Eight hundred nineteen patients were randomly assigned to receive either 15 mg/kg/day of tirilazad mesylate or a placebo containing the citrate vehicle. The two groups were similar in prognostic factors for delayed cerebral ischemia and overall outcome. High-dose tirilazad appeared to be well tolerated because no differences in the incidence of untoward medical events were noted between the two groups. Medical and surgical interventions were no different in the two treatment groups except for hyperdynamic therapy (intentional hypervolemia, induced hypertension, and/or hemodilution), which was more often used in the placebo-treated group to counteract symptomatic vasospasm (24% of patients given placebo compared with 18% of patients given tirilazad, p = 0.02). Mortality rates and overall outcome, assessed using the Glasgow Outcome Scale at 3 months post-SAH, were not different between the two groups, despite a significantly lower incidence of delayed cerebral ischemia in patients given tirilazad. Post hoc subgroup analysis by neurological grade also did not reveal significant differences in outcome, although a trend toward a lower mortality rate favoring the study drug was present in patients with neurological Grade IV and V at admission (32% compared with 37%). Symptomatic vasospasm occurred in 33.7% of the placebo-treated patients as opposed to 24.8% of the patients who were given tirilazad (p = 0.005). The severity of symptomatic vasospasm was also attenuated by administration of the study drug (severe symptomatic vasospasm was reported in 11% of the placebo-treated patients compared with 6% of patients in the tirilazad-treated group (p = 0.008). Clinical cerebral infarction from vasospasm was also reduced from 13% in the vehicle-treated group to 8% in the tirilazad-treated group (p < 0.04). CONCLUSIONS: The authors conclude that high-dose tirilazad mesylate is well tolerated in women with aneurysmal SAH. Although a significant reduction in the incidence of symptomatic vasospasm was observed in the treatment group, the primary end point (mortality rate at 3 months post-SAH) was not affected by the study drug. The use of other potentially effective rescue therapies (that is, hypervolemia, hemodilution, and induced hypertension) to counteract vasospasm may have been responsible for these contrasting observations between the two groups.

Surgical versus medical treatment of spontaneous posterior fossa haematomas: a cooperative study on 205 cases.

22 Italian centres have joined together in a cooperative study aiming to define the ideal management of spontaneous posterior fossa haematomas. 205 cases have been evaluated: 155 cerebellar haematomas and 50 brainstem haematomas. Out of these, 190 cases, all studied by CT scan, are the subject of the present study. Cerebellar haematomas have been divided, according to a tomographic classification, into 3 groups: group 1 (4th ventricle not shifted), group 2 (4th ventricle shifted or obliterated) and group 3 (intraventricular blood). Each group has been subdivided into: A (no hydrocephalus), and B (hydrocephalus). Regardless of therapeutical modalities, mortality rate was 38% for cerebellar haematomas; level of consciousness a few hours after haemorrhage and size of the lesion appeared to be significant prognostic factors. As a whole, medical treatment gave better results than surgical treatment. Considering each tomographical group in detail, surgery should be limited to patients in group 2B and 3B, especially when exhibiting neurological deterioration. For brainstem haematomas, overall mortality was 57%. The possibility of survival was linked to the presence or absence of initial loss of consciousness and to the size of the lesion; while hydrocephalus did not influence the final outcome, ventricular blood was a risk factor. Surgical evacuation showed some value in chronic cases. However, medical treatment appears to be the best policy for brainstem haematomas of limited size; for larger lesions, the outcome appears to be uniformly fatal, regardless of the treatment employed.

Epidemiology and pathophysiology of cerebral vasospasm following subarachnoid hemorrhage.

Cerebral vasospasm still accounts for a significant percent of morbidity and mortality after subarachnoid hemorrhage (SAH). There is a clear-cut temporal course for this phenomenon, with a peak of incidence at the end of the first week after SAH. The occurrence of vasospasm is significantly related to the amount of blood deposited in the subarachnoid cisterns. Non-invasive diagnosis and monitoring of vasospasm is now possible with transcranial Doppler, recording the flow velocity on the middle cerebral artery. Under the current knowledge, the pathophysiology of vasospasm is quite complex: the main biological mechanisms are constituted by the direct contraction of the cerebral arteries, and the impairment of the vasodilatory activity elicited by the endothelium, although other mechanisms cannot be excluded. Some of the observed biological changes are induced by the cisternal clot, with formation of oxyhemoglobin, activation of lipid peroxidation and consequent endothelial injury, impaired nourishment of the arterial wall (encased by the clot). Other biological changes occur in the cerebral arteries, with decreased synthesis of prostacyclin, reduced availability of high energy phosphates, impairment of EDRF-induced vasodilatation and production of the powerful vasoconstrictor endothelin. The final result is arterial contraction, due to phosphorylation of the contractile proteins of the smooth muscle cell. Two mechanisms concur to contraction: a) activation of calcium-calmodulin-dependent protein kinases, and b) elevation of protein kinase C (PKC). While the first mechanism leads to a transient contraction, PKC-induced contraction is lasting for longer time. An additional influence on arterial contraction is played by the protease calpain.

Giant unruptured aneurysm of the middle cerebral artery manifesting with epilepsy: successful surgical treatment.

A case of a giant aneurysm of the middle cerebral artery (M.C.A.), presenting with history of visual hallucinations, is described. The aneurysm was successfully excised, with disappearance of previous symptoms. The interest of the case is constituted by the very unfrequent location for an aneurysm over 3 cm in diameter, by the occurrence of epilepsy as the first symptom and by the excellent response to surgical therapy. The morphology and location of giant aneurysms, their surgical treatment and especially the problem of aneurysm-induced epilepsy are discussed.

Deep controlled hypotension with sodium nitroprusside in the surgical treatment of intracranial arterial aneurysms.

The authors report 73 cases of intracranial arterial aneurysms operated on under deep controlled hypotension--i.e. hypotension below 60 mmHg of systolic arterial pressure (s.a.p.)--. Deep hypotension was induced by Sodium Nitroprusside (SNP). No problems were encountered in order to reach or to maintain deep hypotension. SNP showed to be an easy hypotensive agent, without toxicity at the recommended dosage. Fifty-nine patients were operated on between 40 and 25 mmHg of s.a.p. In 55 patients deep hypotension lasted for 30 minutes or more, reaching 2 hours in 3 patients. Surgical results were excellent, in regard either to the control of bleeding, either to the dissection of the aneurysm. Clinical results were evaluated by comparison with 146 patients operated on under normal pressure (group of control); no complications were clearly related to deep hypotension per se. However, the authors stress the risks of deep hypotension in early surgery, due to the possible association to vascular spasm.