Should we resect peri-lesional hemosiderin deposits when performing lesionectomy in patients with cavernoma-related epilepsy (CRE)?

In this review, the authors perform a database search and summarize and discuss all eligible studies that provide (subgroup) analysis of the postoperative seizure outcome of patients with cavernoma-related epilepsy undergoing sole lesionectomy or lesionectomy including the hemosiderin rim. Based on the currently available data, the authors conclude that if surgical treatment of cavernoma-related epilepsy is performed, the peri-lesional hemosiderin should be resected. However, cases of eloquent or multiple localization or widespread hemosiderin deposit in which a complete resection is challenging should undergo a specific preoperative work-up.

Fibrillary structure is key for hemostasis: a similar effect of collagen fleece and oxidized cellulose on experimental hemorrhagic brain injury.

BACKGROUND: The choice of the ideal hemostatic agent for intraoperative cerebral bleeding is under continuous debate. Our aim was to assess the influence of such materials on bleeding time in hemorrhagic cerebral contusions. We compared oxidized regenerated cellulose in fibrillar form (ORC) to microfibrillar collagen fleece (CF) in an experimental study. METHODS: N=50 Sprague Dawley rats underwent a bilateral craniectomy. 3 separate standardized superficial cortical impacts were inflicted using a high-speed drill. Immediately after lesion placement, each of the 3 lesions was covered with (a) nothing (control), (b) ORC, or (c) CF. We observed the 3 lesions with a surgical microscope. The bleeding times were recorded for each cerebral lesion and compared using ANOVA test. RESULTS: All traumatic lesions produced significant bleeding. The statistical analysis showed a clear reduction in bleeding time for groups treated with either ORC or CF compared to the control group. Lesions covered with ORC and CF showed no significant difference with regard to bleeding time. CONCLUSIONS: ORC and CF significantly reduce blood loss from hemorrhagic contusions. Our data suggest that they effectively reduce bleeding time. We advocate the use of hemostatic material for limiting bleeding from superficial cortical lesions.

Gene expression profiling suggests primary central nervous system lymphomas to be derived from a late germinal center B cell.

To characterize the molecular origin of primary lymphomas of the central nervous system (PCNSL), 21 PCNSLs of immunocompetent patients were investigated by microarray-based gene expression profiling. Comparison of the transcriptional profile of PCNSL with various normal and neoplastic B-cell subsets demonstrated PCNSL (i) to display gene expression patterns most closely related to late germinal center B cells, (ii) to display a gene expression profile similar to systemic diffuse large B-cell lymphomas (DLBCLs) and (iii) to be in part assigned to the activated B-cell-like (ABC) or the germinal center B-cell-like (GCB) subtype of DLBCL.

Cranioplasty for large skull defects with PMMA (Polymethylmethacrylate) or Tutoplast processed autogenic bone grafts.

OBJECTIVE: Aim of the study was a comparison of cranioplasty using the Tutoplast technology for autogenic bone processing and conventional polymethylmethacrylate (PMMA) calvarial re- construction. PATIENTS AND METHODS: A retrospective analysis was carried out in a consecutive series of 61 plastic reconstructions for skull defects, the largest measuring more than 12 cm. Cranioplasty was either performed with PMMA or with the patient's own bone graft which had been recycled using the Tutoplast process. RESULTS: 36 patients with a mean age of 44 (range 10-68) years underwent freehand PMMA cranioplasty following craniectomy for increased intracranial pressure (19 patients, 52.8%), infection (15 patients, 41.7%), or traumatic bone destruction (2 patients, 5.6%). Bilateral procedures were performed in 10 patients (27.8%). Mean follow-up was 44 months. Four patients (11.1%) died, 14 (38.9%) remained severely disabled, and 18 (50%) made a satisfactory recovery. Two patients (5.6%) had PMMA-related complications and required removal. 26 patients exhibited at least satisfactory cosmetic results (83.9%), in 5 patients the results were not satisfactory (16.1%) and in 5 the results are unknown. Twenty-five patients with a mean age of 42 (range 2-68) years received Tutoplast processed autografts following craniectomy for elevated intracranial pressure. Bilateral procedures were performed in 3 patients (12%). Mean follow-up was 15 months. One patient (4%) died, 18 (72%) remained severely disabled, and 6 (24%) made a satisfactory recovery. All patients had satisfactory cosmetic results, but 2 patients (8.3%) required removal at a later stage, one due to infection (4.2%) and one for bone resorption (4.2%). In the 18 patients with follow-up >0.5 years significant resorption occurred in all 5 children and adolescents (100%) and in two adult patients (15.4%). CONCLUSION: Cosmetic results were more satisfactory with Tutoplast processed autografts, and the operating time for unilateral surgery was shorter. Complication rates were similar. Resorption occurred in all children and adolescents, but was rare in adults. Thus, Tutoplast processed autogenic bone grafts can be a reasonable alternative to other methods of cranioplasty in adult patients with large craniotomy defects. Cranioplasty in children and adolescents remains an unsolved problem.

[The trend sport snowblading and its risks]. / Der Trendsport Snowblading und seine Risiken.

The study analysed the results of an examination of 3557 skiing, snowboarding and snowblading injuries treated at the Department of Trauma Surgery at the Klinikum Garmisch-Partenkirchen in winter seasons 99/00 through 02/03. In this study group, a total of 70 injuries occurred while snowblading. These injuries are compared to the remaining injuries resulting from skiing, carving or snowboarding accidents. This study intends to contribute to the tracking and recording of injuries occurring during snowblading, a sport that is popular but not yet well-addressed in medical literature. The results show that snowblading injuries are similar to those of skiing, but different from those attributable to snowboarding, particularly with regard to the affected parts of the body and injury patterns. Acrobatic jumps increase significantly the risk of fractures of the lower extremities. However, ruptures of ligaments, especially of the ACL, are seen more rarely in snowblading than in carving or conventional skiing. Distorsions, on the other hand, are observed significantly more often among snowbladers when compared with carvers and snowboarders. Release bindings for snowblades could reduce the risk of injuries.

Operation for delayed symptomatic brain oedema after treatment of an arteriovenous malformation by embolization and radiosurgery.

A patient with a Spetzler-Martin-grade-III AVM, initially embolized and then stereotactically irradiated, who - with a latency of several months - showed progressive neurological deterioration, is reported. Magnetic resonance imaging revealed enormous ipsilateral brain oedema, which did not respond to dexamethasone. Upon further neurological deterioration the former AVM nidus plus an adjacent rim of brain tissue were removed and the patient recovered considerably. It is concluded that embolization in conjunction with irradiation may impair the blood-brain-barrier with resulting long-term oedema in the surrounding brain, and that surgical treatment should be considered in selected cases.

Sensory gating in the human hippocampal and rhinal regions.

OBJECTIVE: The objective of this work was to ascertain if sensory gating can be demonstrated within the human medial temporal lobe. METHODS: Eight patients with intractable epilepsy with depth electrodes implanted in the medial temporal lobe for pre-surgery evaluation underwent evoked response recording to auditory paired-stimuli (S1-S2). Each of the eight subjects had a diagnosis of left medial temporal lobe epilepsy (MTLE). RESULTS: Data from the non-focal right hippocampi revealed a large negative response on S1 (starting at about 190 ms and lasting for approximately 300 ms from stimulus onset). Rhinal region recordings revealed a positive response (starting at about 240 ms with a rapid incline, followed by a long-lasting decline). A significant attenuation of both responses to S2 stimuli was observed. CONCLUSIONS: Data are suggestive of an involvement of the human medial temporal lobe in the processing of simple auditory information which occurs in a time frame later than the neocortical auditory evoked components. The exact role of these anatomical structures in the sensory gating process remains to be defined. SIGNIFICANCE: This study provides the first evidence of an activation of the rhinal cortex after simple auditory stimulation and provides new evidence that the activation of the medial temporal lobe structures occurs at a later stage than that of the neocortex.

Clonal evolution as pathogenetic mechanism in relapse of primary CNS lymphoma.

Comparative investigation of immunoglobulin (Ig) heavy chain gene rearrangements and DNA sequence analyses of a primary lymphoma of the CNS (PCNSL) and its recurrence revealed that both tumors used the same Ig gene segment. In addition to shared somatic mutations, the primary and the recurrent PCNSLs harbored somatic mutations unique to each tumor. Clonal evolution rather than subclone selection appears to underlie the development of tumor recurrence in this case.

Results for microsurgical removal of tentorial meningiomas.

OBJECTIVE: Growth patterns of tentorial meningiomas are related to the deep cerebral venous system and to cranial nerves IV-XI. Localization and surgical aggressiveness are decisive for the outcome to be expected. PATIENTS AND METHODS: n = 25 patients (22 f, 3 m), aged from 26-77 (mean: 56.4) years underwent microsurgical removal of their tentorial meningioma. Tumor size was as follows: n = 11 < 3 cm, n = 6 3-5 cm, n = 8 > 5 cm. The median of the preoperative Karnofsky scores was 90. The operative approaches chosen were suboccipital in n = 14, subtemporal in n = 6, occasionally a combined supra- and infratentorial approach was chosen. Data regarding surgery, histology and postoperative course were available through the patient's charts and through outpatient clinic. RESULTS: n = 20 (80%) of the tumors were rated WHO grade I, n = 5 (20%) WHO grade II. Tumor removal according to Simpson was degrees I in n = 9 (36%), degrees II in n = 14 (56%), degrees III in n = 2 (8%). Mortality was 0%. In n = 6 patients (24%) neurological worsening, mainly due to transient cranial nerve deficits was noted. Surgical complications (CSF fistula, wound healing problems) occurred in n = 5 patients (20%). The median of the postoperative Karnofsky scores on last follow up was 90 after a median of 41.9 months. Two patients (8%), one of whom underwent reoperation developed tumor recurrency during follow up. CONCLUSIONS: Neurological deficits following microsurgical removal of tentorial meningiomas are transient in the majority of patients. The apparently high rate of incomplete tumor resection (app. 60% Simpson grades II and III) is due to the close topographical relationship of these tumors with important neurovascular structures. Thus, the operative strategy should not be excessively aggressive, but rather take into account the option to observe residual tumor or to apply additional stereotactic convergent beam radiation in selected cases.

Human herpes virus-8 is not associated with primary central nervous system lymphoma in HIV-negative patients.

Primary central nervous system lymphomas (PCNSL) are derived from germinal center B cells. Recent molecular studies indicate that the tumor cells or their precursors have experienced antigenic stimulation. Attractive candidates for such antigens are pathogens with the capacity to reside in the brain. The aim of the present study was to evaluate whether human herpes virus (HHV)-8 is involved in the pathogenesis of PCNSL. A series of 46 PCNSL, 31 from HIV-negative and 15 from HIV-positive patients, were analyzed using various molecular biological and immunological approaches. Nested PCR with two different protocols unequivocally demonstrated that PCNSL from HIV-negative patients did not harbor HHV-8 DNA. Among AIDS-associated PCNSL, HHV-8 DNA was found in only 1 tumor. In situ hybridization studies revealed that the lymphoma cells were HHV-8 negative in all cases. Single small mononuclear cells, most likely corresponding to bystander lymphocytes, were identified as the cellular source of HHV-8 in the HIV-positive patient with an HHV-8 PCR signal. These studies largely rule out a role for HHV-8 in the pathogenesis of PCNSL in both HIV-negative as well as HIV-positive patients.

Fixed and dilated pupils after trauma, stroke, and previous intracranial surgery: management and outcome.

OBJECTIVES: To clarify whether different causative events (trauma, stroke, intracranial surgery), time of intervention, and treatment mode influence outcome, patients with fixed and dilated pupils (FDPs) in a prospective neurosurgical series were evaluated. METHODS: Ninety nine consecutive patients who presented with or developed one or two FDPs, were split into three groups according to the respective aetiology: 46 patients had a trauma, 41 patients a stroke (subarachnoid or intracerebral haemorrhage), and 12 patients had undergone previous elective intracranial surgery. Appropriate therapy was performed depending on the CT findings. Outcome was classified according to the Glasgow outcome scale (GOS). RESULTS: Overall mortality was 75%. In 15% outcome was unfavourable (GOS 2 and 3), and in 10% favourable (GOS 4, 5) at 24 month follow up. No differences in outcome were found between trauma, stroke, and postelective surgery groups. Unilaterally FDP was associated with a better chance of survival (46% v 13%; p<0.01). Age did not correlate with survival, but younger survivors had a significantly better outcome. Patients in whom an intracranial mass was removed surgically had a 42% survival rate, compared with 8% with conservative treatment (p<0.01). Patients with a shorter delay from FDPs to intervention had a better chance of recovery after trauma and previous intracranial surgery (p<0.05). No patient survived better than a vegetative state, if previous FDPs did not become reactive shortly after therapy. If both pupils became reactive on therapy, the chance of survival was 62%. Of these survivors 42% had a favourable outcome. CONCLUSION: Bilateral restoration of pupillary reactivity shortly after therapy is crucial for survival. Surgical evacuation of an intracranial mass, unilateral FDPs, early intervention, and younger age are related to better chances of survival or recovery. The prognosis of patients with FDPs after trauma, stroke, and previous elective intracranial surgery is similar.

Isolation and characterisation of five neurotoxic and cardiotoxic polypeptides from the sea anemone Anthopleura elegantissima.

Five toxins (APE 1 to APE 5) of the sea anemone species Anthopleura elegantissima (Brandt) have been isolated from a toxic by-product fraction of its concentrated crude watery-methanolic extract, prepared previously for the isolation of a neuropeptide (the head-activator) by Schaller and Bodenmüller (Proc. Natl. Acad. Sci. USA 78 (1981) 7000) from 200kg sea anemones. Toxin purification was performed by desalting of the starting material by dialysis (MWCO 3500) against distilled water, anion exchange chromatography on QAE-Sephadex A25 at pH 8, twice gel filtration on Sephadex G50 m, repeated chromatography on QAE-Sephadex at pH 10 and chromatography on the cation exchanger Fractogel EMD SO(3)(-)-650 M.Final purification of the toxins was achieved by HPLC on MN SP 250/10 Nucleosil 500-5 C(18) PPN and MN SP 250/21 Nucleosil 300-7 C(18). Each toxin was composed of at least two isotoxins of which APE 1-1, APE 1-2, APE 2-1, APE 2-2 and APE 5-3 were isolated in preparative scale. With exception of APE 5-3 the sequences of the isotoxins have been elucidated. They resemble the 47 residue type-I long polypeptide toxins native to Anemonia sulcata (Pennant). All isotoxins paralyse the shore crab (Carcinus maenas) by tetanic contractions after i.m. application. The toxins modify current passing through the fast Na(+) channel in neuroblastoma cells, leading to delayed and incomplete inactivation. APE 1-1, APE 2-1 and APE 5-3 produce a positive inotropic effect in mammalian heart muscle, although they differ in potency. The order of potency is APE 2-1>APE 1-1>APE 5-3 (i.e. threshold concentrations are 1, 10 and 300nM, respectively). In addition, they enhance the spontaneous beating frequency in isolated right atria (guinea pig). The most potent cardiotoxic isotoxin is APE 2-1, its sequence is identical with that of AP-C, a toxin isolated and characterised previously by Norton et al. (Drugs and Foods from the Sea, 1978, University of Oklahoma Press, p. 37-50).LD50 APE 2-1:1 micro g/kg b.w. C. maenas (i.m.). LD50 APE 1-1:10 microg/kg b.w. C. maenas (i. m.). LD50 APE 5-3:50 microg/kg b.w. C. maenas (i.m.).

Is there a benefit of preoperative meningioma embolization?

OBJECTIVE: To evaluate the effect of preoperative embolization of meningiomas on surgery and outcomes. METHODS: In a prospective study, 60 consecutive patients with intracranial meningiomas who were treated in two neurosurgical centers were included. In Center A, embolization was performed for none of the patients (n = 30). In Center B, 30 consecutive patients with embolized meningiomas were treated. Preoperatively, tumor size and location, neurological status, and Barthel scale score were recorded. In Center B, the extent of tumor devascularization was evaluated using angiography and postembolization magnetic resonance imaging. Intraoperatively, blood loss, the numbers of blood units transfused, and the observations of the neurosurgeon concerning hemostasis, tumor consistency, and intratumoral necrosis were recorded. Postoperatively, the neurological status and duration of hospitalization were recorded. Six months after surgery, the outcomes were assessed using the Barthel scale and neurological examinations. RESULTS: The mean tumor sizes were 22.9 cc in Center A and 29.6 cc in Center B (P > 0.1). The mean blood losses did not differ significantly (646 ml in Center A versus 636 ml in Center B; P > 0.5). However, for a subgroup of patients with subtotal devascularization (>90% of the tumor) on postembolization magnetic resonance imaging scans in Center B, blood loss was less, compared with the entire group in Center A (P < 0.05). The observations of the neurosurgeon regarding hemostasis, tumor consistency, and intratumoral necrosis did not differ significantly. There were no surgery-related deaths in either center. The rates of surgical morbidity, with permanent neurological worsening, were 20% (n = 6) in Center A and 16% (n = 5) in Center B. There was one permanent neurological deficit (3%) caused by embolization. CONCLUSION: In this preliminary study, only complete embolization had an effect on blood loss. The value of preoperative embolization for all meningiomas must be reconsidered, especially in view of the high costs and risks of embolization.

Limbic encephalitis not associated with neoplasm as a cause of temporal lobe epilepsy.

OBJECTIVE: To describe four patients with temporal lobe epilepsy with limbic encephalitis unrelated to neoplasm. METHODS: The authors performed a retrospective evaluation of patient data obtained during presurgical evaluation, with additional CSF analyses, serum analyses, and histopathologic investigations. RESULTS: The patients shared the following clinical features: onset of the disease in young adulthood with subacute onset or exacerbation of frequent intractable temporal lobe seizures, verbal and visual memory deficits, and affective abnormalities. MRI showed variably extended areas of increased T2 signal in limbic structures and adjacent areas. In the histopathologic investigation, chronic inflammation was observed without evidence of a viral origin. There was no evidence of an underlying malignancy. CONCLUSIONS: Nonparaneoplastic limbic encephalitis should be included in the differential diagnosis of adult patients with temporal lobe epilepsy.

Primary central nervous system lymphomas are derived from germinal-center B cells and show a preferential usage of the V4-34 gene segment.

Primary central nervous system lymphomas (PCNSLs) have recently received considerable clinical attention due to their increasing incidence. To clarify the histogenetic origin of these intriguing neoplasms, PCNSLs from 10 HIV-negative patients were analyzed for immunoglobulin (Ig) gene rearrangements. All tumors exhibited clonal IgH gene rearrangements. Of the 10 cases, 5 used the V4-34 gene segment, and all of these lymphomas shared an amino acid exchange from glycine to aspartate due to a mutation in the first codon of the complementarity-determining region 1. No preferential usage of D(H), J(H), V(kappa), J(kappa), V(lambda), or J(lambda) gene segments was observed. All potentially functional rearrangements exhibited somatic mutations. The pattern of somatic mutations indicated selection of the tumor cells (or their precursors) for expression of a functional antibody. Mean mutation frequencies of 13. 2% and 8.3% were detected for the heavy and light chains, respectively, thereby exceeding other lymphoma entities. Cloning experiments of three tumors showed ongoing mutation in at least one case. These data suggest that PCNSLs are derived from highly mutated germinal-center B cells. The frequent usage of the V4-34 gene and the presence of a shared replacement mutation may indicate that the tumor precursors recognized a shared (super) antigen.

Significance of factors contributing to surgical complications and to late outcome after elective surgery of cerebral arteriovenous malformations.

OBJECTIVES: This study focuses on the relevance of size, eloquence, type of venous drainage, the Spetzler-Martin scale as a whole, and other factors, such as rupture of cerebral arteriovenous malformations (AVMs) for the prediction of neurological deficits in the context of microsurgical AVM removal. METHODS: One hundred and fifty patients with AVMs, whose data were retrieved from a prospectively employed computerised data bank were included. Seventeen patients (11.3%) underwent preoperative embolisation. According to the Spetzler-Martin scale they were graded as follows: 22.0% grade I, 32.0% grade II, 29.3% grade III, 14.0% grade IV, and 2.7% grade V. Intracerebral haemorrhage was present in 39.0%. The AVMs were <3 cm in 52.00/0, 3-6 cm in 43.3% and >6 cm in 4.7%; 59.3% of the AVMs were eloquently located and 29.3% had deep venous drainage (DVD). Follow up information was assessed 6 months after surgery in all but one patient, who died. The applied statistical test was chi2. RESULTS: Surgical morbidity was 15.3%. Early new deficits were noted in 39.3%, permanent new deficits in 10.6%, being significant (major) in 7.3%. The occurrence of permanent deficits correlated significantly with size, deep venous drainage, and the Spetzler-Martin scale. There was statistical evidence for a trend in risk of poor surgical outcome across the three categories non-eloquent, "less eloquent" (for example, visual cortex) and "highly eloquent" (brainstem, basal ganglia, or precentral cortex) with the last being associated with the highest risk for permanent neurological compromise. CONCLUSION: "Eloquence" of the Spetzler-Martin scale should be divided into "highly eloquent" and "less eloquent", which is important for risk analysis of the treatment of asymptomatic and deep seated AVMs and for future trials comparing various treatment modalities. In addition, resection of eloquent AVMs v non-eloquent ones is significantly associated with higher surgical morbidity.

Spondylodiscitis after lumbar discectomy. Incidence and a proposal for prophylaxis.

STUDY DESIGN: An analysis of the incidence of spondylodiscitis after lumbar disc surgery in 1642 patients. In 508 patients no prophylactic antibiotics were given. In 1134 patients a collagenous sponge containing gentamicin was placed in the cleared disc space. OBJECTIVES: To report the incidence of postoperative spondylodiscitis in cases in which no antibiotic prophylaxis was used, and to define the value of a collagenous sponge containing gentamicin in preventing disc space infections. SUMMARY OF BACKGROUND DATA: Spondylodiscitis is considered to be a rare complication of lumbar disc surgery. The retrospective design of most studies and the rare use of magnetic resonance imaging for early radiologic diagnosis suggest that the reported incidence rates may be underestimates. Postoperative spondylodiscitis is the result of intraoperative contamination and, theoretically, could be prevented by treating these patients with prophylactic antibiotics. METHODS: In 1642 patients, 1712 discectomies were performed. In 508 of these patients no prophylactic antibiotics were given; in 1134 of these patients a collagenous sponge containing gentamicin was placed in the cleared disc space. Clinical reexamination and, in cases of unsatisfactory results, laboratory and radiologic investigations were performed 4-8 weeks after surgery. RESULTS: In nineteen of the 508 patients who were not treated with antibiotic prophylaxis (3.7%) a postoperative spondylodiscitis developed, whereas none of the 1134 patients who received antibiotic prophylaxis became symptomatic (P < 0.00001). CONCLUSION: In the current study, a 3.7% incidence of postoperative spondylodiscitis was found in the absence of prophylactic antibiotics. Gentamicin-containing collagenous sponges placed in the cleared disc space were effective in preventing postoperative spondylodiscitis.

Vasospastic reactions in response to the transsylvian approach.

BACKGROUND: Cerebral vasospasm may occur with various neurosurgical procedures such as the treatment of intracranial aneurysms or of skull base tumors. This study was designed to provide more insight into the nature of vasospastic reactions in response to surgical manipulation alone. METHODS: Twenty patients who underwent selective amygdalohippocampectomy for medically intractable epilepsy using the transsylvian approach were studied prospectively. Transcranial Doppler ultrasound (TCD) was used for examination of blood flow velocities within the basal cerebral arteries before and after the operation. RESULTS: Three types of vascular reactions were observed: 1) No or only minimal reaction with increase of the blood flow velocities less than 50% as compared with the preoperative baseline values (N = 4); 2) Ipsilateral/bilateral increase of the blood flow velocities more than 50% of the baselines (N = 14); 3) Paradoxic reactions such as early postoperative resistance flow and contralateral rise of the blood flow velocities (N = 2). There was no morbidity or mortality in this series. CONCLUSIONS: The transsylvian approach is associated with significant changes in hemodynamics--partially caused by mechanical manipulation and partially by the degradation of blood--although the risk of neurological deterioration seems to be low.

Microsurgical results for small arteriovenous malformations accessible for radiosurgical or embolization treatment.

OBJECTIVE: A consecutive series of microsurgically treated small arteriovenous malformations (AVMs), up to 3 cm in diameter, which are theoretically ideal candidates for radiosurgery or embolization, is described. We intended to elucidate the safety and efficacy of the microsurgical removal of AVMs, as compared with the results for radiosurgery and embolization reported in the literature. METHODS: Sixty-two patients (32 female and 30 male patients) ranging in age from 7 to 72 years (mean age, 33.3 yr) were included in the series. Of these, 46.8% presented with intracerebral hemorrhage and 24.2% presented with seizures. The 62 patients underwent microsurgical removal of their small (<3 cm) cerebral AVMs by the same surgeon. Twenty-six AVMs (41.9%) were assigned Spetzler-Martin Grade I, 24 (38.7%) were assigned Grade II, and 12 (19.4%) were assigned Grade III. Thirty-three AVMs (53.2%) were located in eloquent brain regions. All patients underwent postoperative control angiography and clinical follow-up after 3 and 6 months. RESULTS: The AVMs were extirpated, as confirmed by angiography, in all except one patient, thereby accounting for a 98.4% success rate per angiographic findings. The rate of immediate new postoperative neurological deficits or worsening of preexisting neurological deficits was 27.4%, and the rate of permanent significant neurological deficits was 3.2% at late follow-up. The rate of permanent significant deficits occurring after the microsurgical removal of small AVMs in eloquent regions was 6.1%. The mortality rate in the reported series was 0%. The surgical morbidity rate was 9.7%. CONCLUSION: Microsurgery for small AVMs is superior to radiosurgery or interventional neuroradiology because of its high rate of efficacy and low rate of permanent morbidity and because immediate cure of the AVMs can be achieved in the vast majority of patients. The place for radiosurgery in the treatment of small AVMs needs to be more sharply defined after careful assessment of relevant cases by an experienced vascular neurosurgeon.