Deep brain stimulation of subthalamic nuclei affects arm response inhibition in Parkinson's patients.

The precise localizations of the neural substrates of voluntary inhibition are still debated. It has been hypothesized that, in humans, this executive function relies upon a right-lateralized pathway comprising the inferior frontal gyrus and the presupplementary motor area, which would control the neural processes for movement inhibition acting through the right subthalamic nucleus (STN). We assessed the role of the right STN, via a countermanding reaching task, in 10 Parkinson's patients receiving high-frequency electrical stimulation of the STN of both hemispheres (deep brain stimulation, DBS) and in 13 healthy subjects. We compared the performance of Parkinson's patients in 4 experimental conditions: DBS-ON, DBS-OFF, DBS-OFF right, and DBS-OFF left. We found that 1) inhibitory control is improved only when both DBS are active, that is, the reaction time to the stop signal is significantly shorter in the DBS-ON condition than in all the others, 2) bilateral stimulation of STN restores the inhibitory control to a near-normal level, and 3) DBS does not cause a general improvement in task-related motor function as it does not affect the length of the reaction times of arm movements, that is, in our experimental context, STN seems to play a selective role in response inhibition.

Intraoperative localization of subcortical brain lesions.

BACKGROUND: Some brain tumors may grow immediately beneath the cortical surface without distorting its appearance. Intraoperative image guidance promotes safe resection. We have developed MRI-based corticotopography (MRI-bct), to localize lesions during surgery, using simple, non-dedicated equipment, to match a three-dimensional reconstruction with the corresponding appearance of the brain cortex. METHODS: Forty-six patients underwent resection of subcortical brain lesions, aided by MRI-bct. The lesions had a maximum diameter less than 3 cm, were subcortical but no deeper than the floor of the nearest cerebral sulcus. Each patient had a volumetric MRI scan with and without contrast administration. Data sets were transferred to a laptop personal computer and processed using a rendering software. At operation, the three-dimensional model of the brain, including a surface overlay of the lesion, was matched to the exposed brain surface. After its exact relationship with the overlying sulcal pattern was defined, the lesion was localized and resected. In selected patients, the procedure was coupled with functional brain mapping. RESULTS: Data processing took from 10 to 15 min and could be done whenever convenient before operation. Surface matching between the surgical field and the reformatted MRI always required less than 5 min and was done near the operating table. In all patients, the lesion was identified at the first attempt, through a small corticotomy, regardless of the brain shift after dural opening. CONCLUSIONS: MRI-bct is a practical, time-saving neuronavigational aid ideal for localizing superficial lesions underlying the cerebral cortex because it unmistakably characterizes the adjacent sulcal anatomy.

Differential expression of neurogenins and NeuroD1 in human pituitary tumours.

Basic helix-loop-helix (bHLH) transcription factors are involved in neuroendocrine cell growth and differentiation. Though NeuroD1 is viewed as corticotroph specific, its overexpression in non-corticotroph pituitary adenomas (PAs) may reflect the activation of molecular pathways involving other bHLH factors, like neurogenins. To search for neurogenin-NeuroD1 molecular pathways in the human normal and tumoural pituitary. Fifty-one PAs--22 clinically non-secreting (CNS) and 29 secreting respectively--and normal human pituitaries (NP) were studied for NeuroD1 and neurogenins (Ngn1, Ngn2 and Ngn3) gene expression by RT-PCR and quantitative real-time RT-PCR (qRT-PCR). Immunohistochemistry for Ngn2/3 was performed in some cases. NeuroD1, Ngn2, Ngn3 and Ngn1 were observed in up to 84.3, 76.5, 30.4 and 9.1% of PA respectively, only NeuroD1 and Ngn2 being frequently overexpressed when compared with NP. Whereas NeuroD1 expression was higher in corticotroph and CNS adenomas (P=0.0001 versus Pit-1-dependent PA), Ngn2 expression was higher in secreting PA, especially in Pit-1-dependent PA (P=0.007 and P=0.0006 versus CNS respectively). Pit-1-dependent PA which received pre-operative pharmacological treatment expressed higher Ngn2 levels than untreated cases (P=0.025). Nuclear Ngn2 was observed in NP and in most PA, especially ACTH- and GH-secreting adenomas. Nuclear Ngn3 was observed in a minority of secreting PA. Ngn2 is normally expressed in the anterior pituitary and frequently expressed in PA, but does not account for NeuroD1 overexpression where present. Owing to their low and inconstant expression, the biological significance of Ngn1/3 in the adult pituitary is uncertain.

A rapid and reliable procedure to localize subdural electrodes in presurgical evaluation of patients with drug-resistant focal epilepsy.

OBJECTIVES: To evaluate a novel method for localization of subdural electrodes in presurgical assessment of patients with drug-resistant focal epilepsy. METHODS: We studied eight consecutive patients with posterior epilepsy in whom subdural electrodes were implanted for presurgical evaluation. Electrodes were detected on post-implantation brain CT scans through a semiautomated procedure based on a MATLAB routine. Then, post-implantation CT scans were fused with pre-implantation MRI to localize the electrodes in relation to the underlying cortical structures. The reliability of this procedure was tested by comparing 3D-rendered MR images of the electrodes with electrode position as determined by intraoperative digital photography. RESULTS: In each patient, all electrodes could be correctly localized and visualized in a stereotactic space, thus allowing optimal surgery planning. The agreement between the procedure-generated images and the digital photographs was good according to two independent raters. The mean mismatch between the 3D images and the photographs was 2 mm. CONCLUSIONS: While our findings need confirmation on larger samples including patients with anterior epilepsy, this procedure allowed to localize subdural electrodes and to establish the spatial relationship of each electrode to the underlying brain structure, either normal or damaged, on brain convessity, basal and medial cortex. SIGNIFICANCE: Being simple, rapid, unexpensive, and reliable, this procedure holds promise to be useful to optimize epilepsy surgery planning.

Vasospasm of venous grafts in extra-intracranial by-pass. Report of two cases.

Two patients are described, the first with a giant aneurysm of the left carotid bifurcation previously treated by endovascular technique, the second with a bilateral intracavernous aneurysm: both were submitted to high-flow by-pass operation. The first patient was a 40 year-old woman who had presented subarachnoid hemorrhage 6 months before operation. She had been treated by means of a high-flow by-pass between the external carotid artery and the middle cerebral artery. Control angiograms performed 12 hours later showed a stenosis above the suture between the external carotid artery and the venous graft. Angioplasty was performed by endovascular route: new angiograms showed occlusion of the graft while dopplersonography demonstrated the presence of flow within the graft. Angiograms performed 1 week later showed marked vasospasm of the venous graft, of the internal carotid artery, the anterior cerebral artery and the middle cerebral artery. The evolution of spasm of the graft and of the intracranial arterial flow was monitored by dopplersonography and MR-angiography: the latter was performed 20 days after the last angiography and confirmed patency of the graft, while dopplersonography showed resolution of vasospasm. Finally, the aneurysm was embolized. The second patient was a 49 year-old woman with mild left palpebral ptosis and retro-orbital pain. She had already been submitted to high-flow by-pass operation 7 months earlier to treat a right intracavernous aneurysm; the left by-pass was necessary because the intracavernous aneurysm had become symptomatic. One week after surgery, spasm of the venous graft was documented by MR-angiography. In both cases, treatment consisted of calcium antagonists as well as hypertensive and hypervolemic medication, which was successful in treating vasospasm of the venous graft and its symptoms. Spasm of the venous graft, a well-known occurrence in cardiac revascularization, can also be observed in cerebral revascularization.

Evolving criteria for post-operative biochemical remission of acromegaly: can we achieve a definitive cure? An audit of surgical results on a large series and a review of the literature.

Criteria to define the biochemical remission of acromegaly following surgery have changed over the years, and the current use of stringent criteria needs a critical re-evaluation of the surgical results. On the other hand, few data are currently available concerning the possible impact of pituitary surgery on the quality of life of operated acromegalic patients. In this prospective study, we wished to evaluate the initial outcome and long-term recurrence rate in a large series of acromegalic patients operated on by transsphenoidal surgery (TSS), to carefully analyse predictive factors for surgical outcome and to point out possible additional effects of surgery in these patients. Ninety-two out of 98 operated patients could be considered for follow-up. Biochemical remission was strictly defined as plasma GH levels <1 ng/ml during an oral glucose tolerance test (OGTT) and normalisation of age-related IGF-I levels. Hormonal assessment, including an OGTT, was performed 6 months following surgery and then annually to evaluate pituitary function. Fifty-five per cent of patients achieved a biochemical remission of acromegaly. The remission rate at 6 months was 80% for patients with microadenoma and 50% for macroadenoma. Univariate analysis showed that a large extrasellar extension, preoperative high GH levels and dural invasion were correlated with a poor outcome of surgery while, according to multivariate analysis, only invasion of cavernous sinus and preoperative GH levels > 10 ng/ml were independent negative predictors. Mortality was 0% and the overall complication rate was about 10%. Pituitary function worsened in five patients but improved in 16 out of 30 patients with preoperative pituitary defects. No recurrence was observed during a median follow-up of about 8 years. We conclude that TSS is able to achieve a biochemical remission in more than half of acromegalic patients, and that the current criteria for remission seem to indicate a cure in most cases.

A critical reappraisal of MIB-1 labelling index significance in a large series of pituitary tumours: secreting versus non-secreting adenomas.

Pituitary tumours are usually benign neoplasia, but may have a locally aggressive or malignant evolution. This study aimed to identify factors which mostly influence their proliferative activity, in order to clarify its value for clinical and research purposes. The proliferative index was determined in a prospective series of 132 pituitary tumours as the percentage of monoclonal antibody MIB-1-immunopositive cells and referred to as the MIB-1 labelling index (LI). Its distribution was analysed according to both univariate and multivariate models. A life-threatening pituitary tumour is presented separately. The mean LI was 1.24+/-1.59%, with significant differences between clinically secreting (CS) and clinically non-secreting (CNS) adenomas. In CS adenomas (n=65), LI was highly variable and markedly influenced by pre-operative pharmacological treatment (0.80+/-1.03 vs 2.06+/-2.39% in treated vs untreated cases, P=0.009); it decreased with patient's age (P=0.025, r=0.28) and increased with tumour volume and invasiveness. The influence of pre-operative treatment and macroscopic features on LI in this group was confirmed by multivariate analysis. In CNS adenomas (n=67), LI distribution was less variable than in CS adenomas (P<0.0001), it was age-independent and correlations with tumour volume, invasiveness or recurrence did not reach significance. In a rapidly growing parasellar tumour, the mean LI was 24% at first surgery and exceeded 50% at second surgery performed 4 months later. LI should be interpreted according to hormone secretion and pre-operative treatment. Unusually high LI values deserve particular attention.

Epidermal growth factor binding sites in human pituitary macroadenomas.

The number of epidermal growth factor (EGF) binding sites was determined by competitive binding assays in a series of 46 pituitary macroadenomas. A single concentration of 125I-EGF (1 nM) was used for all experiments. In four cases, a displacement curve was obtained by adding increasing concentrations of cold EGF, and Scatchard analysis showed the presence of two classes of EGF binding sites, with Kd1 = 0.62 +/- 0.23 nM and Kd2 = 53.8 +/- 8.2 nM for the high- and low-affinity binding sites respectively. The distribution of EGF binding sites was studied in 42 cases by a single-point assay, in the presence and in the absence of a 100-fold cold EGF excess. A non-parametric distribution of EGF binding sites was observed (median 10.2 fmol/mg membrane protein, range 0.0-332.0). EGF-receptor positivity, defined as EGF binding > or = 10.0 fmol/mg protein, was observed in 23 samples (54.8%), especially in prolactinomas (76.5%, P < 0.05 vs other tumors taken together) and in gonadotrope adenomas (62.5%). EGF binding was higher in invasive than in non-invasive adenomas (median: 12.8 vs 0.0 fmol/mg membrane protein, P = 0.047), and especially in adenomas invading the sphenoid sinus (median 26.7 fmol/mg membrane protein, P = 0.008 vs other adenomas). EGF binding also tended to increase with the grade of supra/extrasellar extension according to Wilson (P = 0.15). Sex steroid receptors (SSRs) were simultaneously determined in both cytosolic and nuclear fractions of 31 pituitary adenomas. Estrogen and progesterone receptors were determined by an enzyme-linked immunoassay and androgen receptors by a competitive binding assay with [3H]methyltrienolone. No correlation could be found between EGF binding and either the gender and gonadal status of the patients, or the expression of SSRs by the adenomas. We conclude that the EGF family of growth factors may play a role in the evolution of a significant subset of human pituitary adenomas, especially in their invasiveness, and that a high EGF binding capacity may represent an additional marker of aggressiveness for these tumors. Sex steroids do not appear to have a significant role in the regulation of EGF binding in vivo in these tumors.

Cerebral hemodynamics on MR perfusion images before and after bypass surgery in patients with giant intracranial aneurysms.

BACKGROUND AND PURPOSE: Preoperative assessment of the anatomy and dynamics of cerebral circulation for patients with giant intracranial aneurysm can improve both outcome prediction and therapeutic approach. The aim of our study was to use perfusion MR imaging to evaluate cerebral hemodynamics in such patients before and after extraintracranial high-flow bypass surgery. METHODS: Five patients with a giant aneurysm of the intracranial internal carotid artery underwent MR studies before, 1 week after, and 1 month after high-flow bypass surgery. We performed MR and digital subtraction angiography, and conventional and functional MR sequences (diffusion and perfusion). Surgery consisted of middle cerebral artery (MCA)-internal carotid artery bypass with saphenous vein grafts (n = 4) or MCA-external carotid artery bypass (n = 1). RESULTS: In four patients, MR perfusion study showed impaired hemodynamics in the vascular territory supplied by the MCA of the aneurysm side, characterized by significantly reduced mean cerebral blood flow (CBF), whereas mean transit time (MTT) and regional cerebral blood volume (rCBV) were either preserved, reduced, or increased. After surgery, angiography showed good canalization of the bypass graft. MR perfusion data obtained after surgery showed improved cerebral hemodynamics in all cases, with a return of CBF index (CBFi), MTT, and rCBV to nearly normal values. CONCLUSION: Increased MTT with increased or preserved rCBV can be interpreted as a compensatory vasodilatory response to reduced perfusion pressure, presumably from compression and disturbed flow in the giant aneurysmal sac. When maximal vasodilation has occurred, however, the brain can no longer compensate for diminished perfusion by vasodilation, and rCBV and CBFi diminish. Bypass surgery improves hemodynamics, increasing perfusion pressure and, thus, CBFi. Perfusion MR imaging can be used to evaluate cerebral hemodynamics in patients with intracranial giant aneurysm.

A new type of prehensile suction device.

The authors describe a new suction device with prehensile properties that has proved itself particularly useful in the removal of certain types of tumor, especially extramedullary.

Supratentorial ependymomas of the first two decades of life. Long-term follow-up of 20 cases (including two subependymomas).

In order to better elucidate the lesser known aspects of the biological behavior and prognosis of supratentorial ependymomas in children and young adults, we studied a series of 20 patients, ages 1 to 20 years. The tumor site was extraventricular in 14 cases and intraventricular in 6 (including one third ventricle tumor). Histologically, according to World Health Organization criteria, there were 12 ependymomas (E), 2 subependymomas (SE), and 6 malignant ependymomas (ME). Of the 18 patients surviving surgery, 12 (66.6%) are alive and disease free 63 to 252 months (mean, 146 mo) after the operation; 9 harbored an E, 2 had an SE and 1 had an ME. Four patients are now out of risk of recurrence according to Collin's law. Six of the long-term survivors (50%), four E and two SE, did not receive postoperative radiotherapy. However, two patients with E, initially treated by surgery alone, had a recurrence and one subsequently died. Two ME patients showed signs of spinal metastases after subsequent operation for recurrence and shortly before death. Considering the partially good results as well as failures after surgery alone in our and in other series and the risks of irradiating the child's brain, we tried to elucidate in what cases radiotherapy could be reasonably withheld, or alternatively, when prophylactic craniospinal irradiation should be prescribed. The main conclusions of our study are the following: 1) Radical surgery alone is a reasonable option as the initial treatment for lateral ventricle tumors and for solid extraventricular tumors located far from eloquent brain areas, provided the histology is benign, especially if of the SE type.(ABSTRACT TRUNCATED AT 250 WORDS)

Orbital schwannomas: report of nine cases and review of the literature.

The authors report 9 cases of orbital schwannoma out of a total of 148 orbital tumors operated. The computed tomography (CT) scan is considered superior to other methods used in the radiological work-up of endoorbital tumors because, in addition to being noninvasive, it gives direct visualization of the lesion and more precise localization both with respect to the muscular cone and tridimensionally. Unfortunately, preoperative diagnosis is not always possible solely on the basis of the CT scan because the enhancement of the tumor is not constant, thus making differential diagnosis with meningioma and cavernous angioma problematic. In addition, CT enables the surgeon to choose the best route for tumor removal. Operative results are good and are influenced by the use of microsurgical techniques.

Intradural lumbar disc hernia: description of three cases.

Three new cases of intradural lumbar disc hernia are added to the 25 previously published cases. The clinical features of the lesion, which usually occurs at the level of the cauda equina, and its pathogenesis are discussed.

Spontaneous occlusion of supraclinoid aneurysms after the creation of extra-intracranial bypasses using long grafts: report of two cases.

OBJECTIVE: We describe two cases of giant supraclinoid aneurysms, treated by means of saphenous vein grafting between the external carotid artery and the middle cerebral artery, which unexpectedly spontaneously occluded. CLINICAL PRESENTATION: Two patients presented with subarachnoid hemorrhage and headache, respectively. In the first case, angiography showed an aneurysm of the right internal carotid artery (ICA), which had been treated by clipping. Repeat angiography showed a giant aneurysm of the right ICA, the formation of which was probably caused by sliding of the clip that had been applied during the previous operation. The patient was operated on again, but it was impossible to exclude the aneurysm because no clear neck could be identified. In the second case, magnetic resonance imaging and cerebral angiography showed a large, partially thrombosed aneurysm of the supraclinoid segment of the left ICA. TECHNIQUE: In view of the patients' ages and the statuses of compensatory circulation, each patient underwent cerebral revascularization with a long saphenous vein graft placed between one branch of the middle cerebral artery and the external carotid artery, in anticipation of subsequent endovascular treatment of the aneurysm and/or closure of the ICA in the neck. Postoperative angiography demonstrated spontaneous occlusion of the aneurysms. CONCLUSION: Thrombosis of an aneurysm may occur spontaneously or after explorative surgery. However, it should be remembered that spontaneous occlusion of an aneurysm may be induced or favored by hemodynamic vascular alterations that take place inside the aneurysm after a high-flow extra-intracranial bypass has been created.

Hemorrhagic pituitary adenomas: clinicopathological features and surgical treatment.

Forty-five (9.9%) of 453 pituitary adenomas operated on between January 1973 and November 1988 demonstrated hemorrhagic changes at surgery: 24 had a blood collection, 12 had a blood collection associated with hemorrhagic necrosis, and 9 had hemorrhagic necrosis. Thirteen patients (28.9%) experienced the acute symptoms of pituitary apoplexy, whereas another 32 had an "asymptomatic" hemorrhage, that is, the clinical course was comparable to an uncomplicated adenoma. Nineteen tumors (42.2%) showed marked suprasellar extension, 8 (17.8%) showed moderate extension, and 11 (24.5%) showed slight extension; another 2 (4.4%) were laterosellar and 5 (11.1%) were intrasellar. Invasive behavior was present in 32 cases (71.1%) and this may suggest another hypothesis to explain the pathogenesis of tumoral hemorrhage. The incidence of hemorrhagic complications in invasive adenomas with marked suprasellar extension was particularly impressive; therefore, we do not suggest preoperative bromocriptine treatment in this type of tumor. Two of 14 patients operated on by the transcranial route died after surgery, whereas there was no operative mortality in the 31 patients operated on by the transsphenoidal route. It proved advantageous to operate as early as possible, even during the acute phase of pituitary apoplexy. The transsphenoidal approach gave the best results, but to achieve satisfactory late results multidisciplinary treatment was necessary, namely, postoperative radiotherapy in 23 patients, bromocriptine in 12, and endocrine replacement therapy in almost all. In an average follow-up period of 6.2 years, 5 (11.1%) symptomatic recurrences were observed.

Surgical management of orbital cavernous angiomas: prognosis for visual function after removal.

The authors report the outcome of surgical treatment in a group of 25 patients with cavernous angioma of the orbital cavity. In the majority of cases, good esthetic results were appreciable within a few days of surgery. However, the onset or deterioration of preexisting visual deficits, in spite of the complete preservation of the optic nerve in a third of these patients, draws attention to the need for accurate surgical timing.

Mucoceles of the paranasal sinuses with intracranial and intraorbital extension: report of 28 cases.

Twenty-eight patients received surgical treatment for a paranasal sinus mucocele with intracranial and/or intraorbital extension. The lesions were classified by site and extension: anterior without intracranial extension (Type 1), 7 patients; anterior with intracranial extension (Type 2), 11 patients; posterior midline without intracranial extension (Type 3), 5 patients; and posterior with intracranial extension (Type 4), 5 patients. The surgical approaches were: transnaso-orbital, transfrontonaso-orbital, transsphenoidal, transmaxillosphenoidal, and subfrontal transbasal; the choice depended on the site and extension of the lesion, with the aim of securing maximum exposure to ensure total removal of the lesion with its capsule. A transcranial approach was reserved for mucoceles possessing an intracranial extension or causing distension of the bone structures with optic pathway neurological symptoms. With a coronal or transfacial skin incision along the lines of the forehead, nose, and orbital muscles of expression and careful reconstruction, the patients' natural cast of features was spared or restored in a single operation.

Meningiomas of Meckel's cave.

A series of 16 patients with meningiomas of Meckel's cave is reported. Trigeminal neuralgia, typical or atypical, was the initial symptom in 10 patients (62.5%). At admission, trigeminal signs and symptoms were present in 15 patients (93.7%); in 7 patients (43.7%), trigeminal dysfunction was combined with the impairment of other cranial nerves. On retrospective analysis, these patients fall into two clinical groups that differ also in prognosis. Group 1 comprises eight patients with trigeminal signs and symptoms only. These patients had small meningiomas strictly affecting Meckel's cave. Total removal of the tumor was achieved in seven of eight patients, without adjunctive postoperative neurological deficits. In this group, there were no tumor recurrences. Group 2 comprises the other eight patients in whom trigeminal dysfunction was combined with impairment of other cranial nerves. These patients had large tumors arising from Meckel's cave and secondarily invading the cavernous sinus (five patients) or extending into the posterior fossa (two patients) or largely growing into the middle fossa (one patient). Total removal was achieved in only one patient, and a worsening of the preoperative neurological status was observed in four patients; there were three cases of tumor progression. A subtemporal intradural approach (used in the past in every case) is still used for the small tumors of Group 1 with good results. Since 1985, for tumors involving the cavernous sinus, we have employed a frontotemporal craniotomy with extradural clinoidectomy and superior and lateral approach to the cavernous sinus. When the tumor extends toward the posterior fossa, we use a combined temporosuboccipital-transpetrosal approach.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral oligodendroglioma: prognostic factors and life history.

The records of 137 patients with supratentorial oligodendroglioma treated surgically between 1953 and 1986 were reviewed. The tumors were rated histologically benign or malignant. In the 105 patients followed up with a minimum observation time of 5 years to December 1991, the mean postoperative survival was 90.2 months (standard error, 9), the median 64 months (standard error, 9.6), the 5-year survival rate 52.4%, and the 10-year survival rate 24%. Sixteen possible prognostic factors, broken down into two or more variables each, were considered in the survival study on univariate methods (5-year survival rate, survival curves, and Cox's hazard function) and on multivariate analysis according to Cox's stepwise proportional hazards model. The latter showed that variables correlated positively with survival were benign histological findings (P, 0.000), postoperative radiation therapy (P, 0.004), and time of operation from 1977 to 1986 (P, 0.044) in 105 patients of the whole series, and period of surgery from 1977 to 1986 (P, 0.000), subtotal or total surgical resection of the tumor (P, 0.001), and radiation therapy (P, 0.005) in the subgroup of 79 patients operated on for benign tumors. However, the most interesting point to emerge from the study was the relevance of admission clinical status to the survival of patients who did not receive radiation therapy and to the prognostic response of those who did. Of the 40 patients with seizures and negative neurological status--Clinical Syndrome A--the 10 who did not receive radiation therapy had survived as long as the 30 who did (5-year survival rate, 80 versus 67%; P, not significant; median survival, 122 versus 85 months; Breslow and Mantel-Cox P, not significant), whereas of the 65 patients with intracranial hypertension and/or neurological deficits--Clinical Syndrome non-A--the 18 who did not receive radiation therapy had short survival times, and the 47 who did fared significantly better (5-year survival rate, 11 versus 53%; P, 0.002; median survival, 32 versus 64 months; Breslow and Mantel-Cox P, 0.000). These findings were not significantly affected by the exclusion of malignant neoplasms and in the group of benign tumors, in which the histological characteristics have not been found to be significantly different between those with A and those with non-A clinical syndrome, did not depend on different frequencies of subtotal or total tumor removal.(ABSTRACT TRUNCATED AT 400 WORDS)

A simple method for stereotactic microsurgical excision of small, deep-seated cavernous angiomas.

Eight patients underwent microsurgical excision of small, deep-seated cavernous angiomas (maximum diameter, 0.9 to 2 cm; distance from cortical surface, 3.5 to 6.5 cm) by the stereotactic implantation of a guide catheter. In all cases, the lesion was quickly localized and completely removed. None of the patients had postoperative neurological deficits. Once the guide catheter has been implanted, the stereotactic headframe can be removed, allowing the unobstructed use of the operating microscope with frames not suitable for open surgery. Target localization is not affected by brain movement, which is inevitable during open surgery. The procedure described here is simple to perform and relatively inexpensive. It requires no specially designed equipment, only a standard stereotactic apparatus, an operating microscope, and the usual microsurgical instruments.