Supratentorial Meningiomas Research Articles

Levetiracetam seizure prophylaxis in craniotomy patients at high risk for postoperative seizures

Background:The risk of developing immediate postoperative seizures in patients undergoing supratentorial brain tumor surgery without anti-epileptic drug (AED) prophylaxis is 15-20%. Patients who present with pre-operative seizures and patients with supratentorial meningioma or supratentorial low grade gliomas are at significantly higher risk. There is little data on the efficacy of levetiracetam as a prophylactic AED in the immediate postoperative period (within 7 days of surgery) in these patients.Methods:We conducted a retrospective chart review of 165 adult patients classified as higher risk for postoperative seizures who underwent brain tumor resection at Duke University Hospital between time May 2010 and December 2011. All patients had received levetiracetam monotherapy in doses of 1000-3000 mg/day in the immediate postoperative period.Results:We identified 165 patients with following tumor locations: Frontal 83 (50.3%), Temporal 37 (22.4%), Parietal 30 (18.2%), Occipital 2 (1.2%) and 13 (7.8%) with single lesions involving more than one lobe. Histology revealed: Glioma 98 (59.4%), Meningioma 57 (34.5%) and Brain Metastases 6 (3.6%). Preoperatively, 88/165 (53.3%) patients had presented with seizures. 12/165 patients (7.3%) developed clinical seizures (generalized 10, partial 2) in the immediate post-operative period. Other than somnolence in 7 patients (4.2%), no major side-effects were noted.Conclusions:The incidence of seizures was significantly lower in patients treated with levetiracetam (7.3%) when compared with the expected (15-20%) rate without AED prophylaxis based on the previous literature. Levetiracetam appears effective and safe for seizure prevention in patients undergoing brain tumor resection and who are at significantly higher risk of developing post-operative seizures. These findings warrant confirmation in a prospective randomized trial.

Early and late postoperative seizure outcome in 97 patients with supratentorial meningioma and preoperative seizures: a retrospective study

We identified factors associated with early and late postoperative seizure control in patients with supratentorial meningioma plus preoperative seizures. In this retrospective study, univariate analysis and multivariate logistic regression analysis compared 24 clinical variables according to the occurrence of early (≤1 week) or late (>1 week) postoperative seizures. Sixty-two of 97 patients (63.9 %) were seizure free for the entire postoperative follow-up period (29.5 ± 11.8 months), while 13 patients (13.4 %) still had frequent seizures at the end of follow-up. Fourteen of 97 patients (14.4 %) experienced early postoperative seizures, and emergence of new postoperative neurological deficits was the only significant risk factor (odds ratio = 7.377). Thirty-three patients (34.0 %) experienced late postoperative seizures at some time during follow-up, including 12 of 14 patients with early postoperative seizures. Associated risk factors for late postoperative seizures included tumor progression (odds ratio = 7.012) and new permanent postoperative neurological deficits (odds ratio = 4.327). Occurrence of postoperative seizures in patients with supratentorial meningioma and preoperative seizure was associated with new postoperative neurological deficits. Reduced cerebral or vascular injury during surgery may lead to fewer postoperative neurological deficits and better seizure outcome.

Predictive value of electrocorticography for postoperative epilepsy in patients with supratentorial meningioma

This study examines electrocorticography (ECoG) signals in patients with supratentorial meningioma before and after tumor resection, and discusses its predictive value with regard to postoperative epilepsy. Ninety-one patients with supratentorial meningioma, who presented with seizures, were studied. Patients were followed-up for 2 to 5years, and the occurrence rate of postoperative epilepsy in each group was compared. Depending on the frequency and amplitude variation in multiple spike waves on ECoG, patients were divided into those with an increase in epileptic discharge (Group A), those with no change (Group B), and those with a reduction in epileptic discharge (Group C). Postoperative seizures was classified as early postoperative seizures (within 1week of surgery) or late postoperative seizures (> 1week after surgery). After lesion resection and measurement of ECoG, the 91 patients were divided into Group A (12 patients, 13.19%), Group B (36 patients, 39.56%) and Group C (43 patients, 47.25%). Of these 91 patients, 29 (31.87%) had early postoperative seizures of which seven patients (58.33%) were from Group A, 13 (36.11%) were from Group B and nine (20.93%) were from Group C (χ2=6.53, p<0.05). Seventeen patients (18.68%) had late postoperative seizures, of which two patients (16.67%) were from Group A, seven were from Group B (19.44%) and eight were from Group C (18.60%) (χ2=0.05, p>0.05). Of the 29 patients with early postoperative seizures, seven (24.14%) also had late postoperative epilepsy. Of the 62 patients who did not experience early postoperative seizures, 10 (16.13%) also had late postoperative epilepsy (χ2=0.83, p>0.05). Thus, the change in ECoG before and after resection in patients with supratentorial meningioma has a predictive value for early postoperative seizures.

Predictive value of brain edema in preoperative computerized tomography scanning on the recurrence of meningioma

IntroductionMeningioma is a common benign intracranial tumor. The most common histological subtypes are the transitional and mesothelial subtypes. It can be cured by adequate excision, which is mostly measured by the Simpson grading system. Meningioma can have a peritumoral edema seen in the preoperative computerized tomography as well as in magnetic resonance imaging. It is caused by the release of vasogenic factors that causes leak of fluid from the blood vessels into the brain parenchyma. Recurrence of meningioma has been linked to the presence of preoperative peritumoral brain edema. AimThe aim of this study is to predict the possibility of meningioma recurrence based on the extent of brain edema in the preoperative computerized scanning of the brain. MethodsTwenty five patients with supratentorial meningioma were retrospectively studied for the relationship between preoperative peritumoral brain edema as measured by the brain edema index and the recurrence of meningioma. ResultsThe age of the patients ranged from 26 to 69years. Males and females had almost equal percentages. Most of the cases recurred within a period from 3years to less than 6years; while the least recurrence occurred within one year of the surgery. Most of the cases of recurrent meningioma had high brain edema index. The higher the brain edema index, the less average years required for recurrence. The higher the preoperative brain edema index, the higher the possibility of postoperative complications. Tumors at a maximum diameter of three to less than six cm represented the majority of cases. Peritumoral brain edema was present in all cases in sphenoid ridge and parasagittal site. ConclusionPreoperative brain edema as measured by brain edema index on the preoperative brain computerized tomography scan had an important impact on the postoperative complication rate as well as on the incidence of tumor recurrence.

Vascular endothelial growth factor A protein level and gene expression in intracranial meningiomas with brain edema

Meningiomas are the second most common primary intracranial tumors in adults. Although meningiomas are mostly benign, more than 50% of patients with meningioma develop peritumoral brain edema (PTBE), which may be fatal because of increased intracranial pressure. Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen and angiogen. VEGF-A protein, which is identical to vascular permeability factor, is a regulator of angiogenesis. In this study, 101 patients with meningiomas, and possible co-factors to PTBE, such as meningioma subtypes and tumor location, were examined. Forty-three patients had primary, solitary, supratentorial meningiomas with PTBE. In these, correlations in PTBE, edema index, VEGF-A protein, VEGF gene expression, capillary length, and tumor water content were investigated. DNA-branched hybridization was used for measuring VEGF gene expression in tissue homogenates prepared from frozen tissue samples. The method for VEGF-A analysis resembled an ELISA assay, but was based on chemiluminescence. The edema index was positively correlated to VEGF-A protein (p = 0.014) and VEGF gene expression (p < 0.05). The capillary length in the meningiomas was positively correlated to the PTBE (p = 0.038). If VEGF is responsible for the formation of PTBE, the edema may be treated with the anti-VEGF drug Bevacizumab (Avastin), which has been shown to reduce PTBE in patients with glioblastoma multiforme.

Editorial: Postoperative antiepileptic drugs

In this issue, Komotar and colleagues1 report the results of their “meta-analysis” of publications describing the incidence of postoperative seizures with and without the use of prophylactic antiepileptic drugs (AEDs) in patients with supratentorial meningiomas. They identified 16 articles, 13 of which provided seizure outcome for patients treated with AED prophylaxis, 3 of which did the same for patients not treated with AEDs, and 3 of which compared patient groups. The patients in these series varied with respect to their duration of anticonvulsant treatment and the agent and dose used, as well as their length of follow-up. The authors’ findings agree with recent case series that have demonstrated no clear evidence that AEDs prevent the occurrence of postoperative seizures in these patients. Furthermore, the paper provides a good review of the literature, and can serve as the reference basis for future trials. The authors acknowledge the limitations of their approach to summarizing and analyzing the existing literature and suggest that more prospective studies would be needed to more completely answer the various practical questions that arise in clinical decision-making in this setting. A number of further questions do arise: 1. In other conditions, such as brain injury, early AED use decreases the risk of early, but not late, seizures. Do the authors think that there are potentially different risks or benefits resulting from strategies that would potentially reduce the risk of early versus late seizures in patients following surgery for meningioma? 2. Is there evidence that the occurrence of an early seizure changes the patient’s outcome with respect to the development of late seizures or neurological deficits? 3. Although the authors mention the potential importance of tumor location in the genesis of postoperative seizures, neither the text nor the tables compare tumor location between patients who received AEDs and those who did not. Are there data on this question, and if so, how would this inform the design of future studies? The authors do acknowledge that “meta-analyses” are methodologically imperfect and concede that their findings, though convincing, cannot be interpreted with the same certainty as a randomized controlled trial. The term “meta-analysis” seems to have myriad definitions, some rigorous, and others descriptive. It is not equivalent to a structured review, which is how I would characterize this paper. From the statistical perspective, a meta-analysis is a technique that seeks to combine results from different existing studies to obtain a more accurate estimate of effect size. The analysis should weight the sample sizes involved, such that larger samples would have more statistical impact. There are a number of statistical methods to produce this aggregate estimation of effect. Simply combining subjects into a pooled sample does not achieve this goal. “Meta-analysis,” however defined, also has a certain mystique attached to it. It is important to recognize that the results of such an analysis can be highly questionable when the included studies employ varying research methods or definitions or when the study selection process is somehow biased. Ultimately, a randomized controlled and blinded clinical trial will be necessary to answer the question of whether or not prophylactic AED therapy should be used to prevent early and late seizures after meningioma surgery. This paper provides the impetus and foundation for such a definitive trial.

Prophylactic antiepileptic drug therapy in patients undergoing supratentorial meningioma resection: a systematic analysis of efficacy

Meningiomas are one of the more common intracranial neoplasms. The risk of seizures and secondary aspiration, brain edema, and brain injury often leads practitioners to administer prophylactic antiepileptic drugs (AEDs) perioperatively. The efficacy of this practice remains controversial, however, with prior investigations reaching conflicting results and recent studies focusing on AED side effects. The authors performed a systematic analysis of outcomes following supratentorial meningioma resection with and without prophylactic AED administration in the hope of clarifying the role of AEDs in the perioperative care of patients with these lesions. A MEDLINE search of the literature (1979-2010) was performed. Comparisons were made for patient and tumor characteristics as well as success of repair, morbidity, and seizure outcome. Statistical analyses of categorical variables were undertaken using chi-square and Fisher exact tests. Nineteen studies, involving 698 patients, were included. There were no significant differences in the extent of resection, perioperative mortality, or recurrence between the AED and no-AED cohorts. Likewise, there were no significant differences in the incidence of early or late seizures between the cohorts. The results of this systematic analysis supports the conclusion that the prophylactic administration of anticonvulsants during resection of supratentorial meningiomas provides no benefit in the prevention of either early or late postoperative seizures. Despite their traditional role in this patient population, the routine use of AEDs should be carefully reconsidered.

Lateral Supraorbital Approach Applied to Anterior Clinoidal Meningiomas: Experience With 73 Consecutive Patients

Anterior clinoidal meningiomas (ACMs) are a subgroup of meningiomas accounting for less than 10% of supratentorial meningiomas. To assess the reliability and safeness of the lateral supraorbital approach (LSO) to remove ACMs. Between September 1997 and October 2009, a total of 73 ACM patients were operated on at the Department of Neurosurgery, Helsinki University Central Hospital, by the senior author (J.H.). We retrospectively analyzed the clinical data, radiological findings, surgical treatment, histology, and outcome of patients, and discuss the operative technique. Seventy-three patients were operated on by applying the LSO approach. Apparently complete removal was achieved in 57 patients (78%). Anterior clinoidectomy was performed in 21 cases. Preexisting visual deficit improved in 11 of 39 patients and worsened in 4; 3 had de novo visual deficit. At 3 months after discharge, 60 (82%) patients had a good recovery, 9 (12%) patients were moderately disabled, 1 presented with severe disability, and 3 (4%) patients died of surgery-related causes. Sixteen (22%) patients had residual tumors, 6 of which required reoperation. During the median follow-up of 36 months (range, 3-146), tumor recurred in 3 patients: 2 were followed-up and 1 was reoperated on. ACMs can be removed via the LSO approach with relatively low morbidity and mortality. Anterior clinoidectomy is required only in selected cases, and we prefer the intradural approach during the LSO approach. High-power coagulation should be avoided in proximity of the optic nerve.

Expression of aquaporin-4 in human supratentorial meningiomas with peritumoral brain edema and correlation of VEGF with edema formation

Peritumoral brain edema is a common complication of meningiomas. It is believed that vascular endothelial growth factor (VEGF), as an angiogenic factor, plays a vital role in edema formation. Aquaporin-4 (AQP4) is a small integral membrane protein that regulates water in the normal brain. However, the expression of AQP4 and its relationship to VEGF in edematous meningiomas are not well known. We studied tumor specimens of 59 human supratentorial meningiomas. Western blot analysis was used to detect the expression of AQP4, and double-labeling immunofluorescence histochemical staining was performed to determine the relationship between AQP4 and VEGF. The AQP4 expression was significantly higher in the edema group, in which the protein level was correlated with the extent of edema. Greater VEGF expression was also observed in the edema group, and a relationship between AQP4 and VEGF was found. We conclude that AQP4 is involved in peritumoral brain edema formation in meningiomas and is also closely related to the expression of VEGF.

Radiosurgery for large-volume (&gt; 10 cm3) benign meningiomas

Stereotactic radiosurgery (SRS) has proven to be a safe and effective treatment for many patients with intracranial meningiomas. Nevertheless, the morbidity associated with radiosurgery of larger meningiomas is poorly understood. The authors performed a retrospective review of 116 patients who underwent SRS for meningiomas (WHO Grade I) > 10 cm3 between 1990 and 2007, with a minimum follow-up of 12 months. Patients with atypical or malignant meningiomas and those who received prior radiotherapy were excluded. The average tumor volume was 17.5 cm3 (range 10.1-48.6 cm3); the average tumor margin dose was 15.1 Gy (range 12-18 Gy); and the mean follow-up duration was 70.1 months (range 12-199 months). Tumor control was 99% at 3 years and 92% at 7 years after radiosurgery. Thirty complications after radiosurgery were noted in 27 patients (23%), including 7 cases of seizures, 6 cases of hemiparesis, 5 cases of trigeminal injury, 4 cases of headaches, 3 cases of diplopia, 2 cases each of cerebral infarction and ataxia, and 1 case of hearing loss. Patients with supratentorial tumors experienced a higher complication rate compared with patients with skull base tumors (44% compared with 18%) (hazard ratio 2.9, 95% CI 1.3-6.7, p = 0.01). The morbidity associated with SRS for patients with benign meningiomas > 10 cm(3) is greater for supratentorial tumors compared with skull base tumors. Whereas radiosurgery is relatively safe for patients with large-volume skull base meningiomas, resection should remain the primary disease management for the majority of patients with large-volume supratentorial meningiomas.

Pre-Operative Factors Affecting Resectability of Giant Intracranial Meningiomas

Larger intracranial tumors require extended operating times and may be associated with increased perioperative complications. There are few reports describing the experience of resecting large meningiomas > or =5cm in a variety of locations. As a group, it remains largely unknown whether these relatively rare lesions are amenable to radical resection, and what factors influence their resectability. Sixty-seven patients undergoing surgery for a large intracranial meningioma (> or =5cm in the longest dimension) between 1998 and 2004 were retrospectively reviewed. The surgeries were performed at a single institution University of California at San Francisco. Predictors of resectability were assessed via multivariate logistical regression analysis. Thirty-nine (58%) patients underwent gross total resection (GTR) (Simpson grades I/II). There were no cases of perioperative mortality. At last follow-up, symptoms improved in 39 (58%) patients, remained unchanged in 20 (30%), and were aggravated in 8 (12%). In the multivariate model for all large meningiomas, age>45 years [OR (95%CI); 0.127 (0.026-0.616), p=0.01] and superior sagittal sinus involvement [OR (95%CI); 0.160 (0.026-0.976), p=0.05] were negative predictors of GTR, while preoperative embolization [OR (95%CI); 8.087 (1.719-38.044), p=0.008] was positively associated with GTR. For only supratentorial meningiomas, superior sagittal sinus involvement [OR (95%CI); 0.077 (0.010-0.571), p=0.01] and preoperative embolization [OR (95%CI); 10.492 (1.961-56.135), p=0.006] were independently associated with GTR. This study evaluated a subset of large intracranial meningiomas > or =5cm. The results indicate that GTR can be achieved in the majority of cases with limited morbidity and mortality, where symptoms will likely improve and recurrences seldom occur. This study may provide useful insights for patients undergoing surgery for large intracranial meningiomas.

ASSESSMENT OF NEUROPSYCHOLOGICAL PARAMETERS AND QUALITY OF LIFE TO EVALUATE OUTCOME IN PATIENTS WITH SURGICALLY TREATED SUPRATENTORIAL MENINGIOMAS

According to current outcomes research programs, assessment of a broad spectrum of parameters, including quality of life indices, is required to adequately reflect the results of a given treatment. We performed a comprehensive evaluation in patients after supratentorial meningioma surgery in a retrospective study. In 91 consecutive patients, outcome was assessed in individual sessions in patients' homes an average of 15 months (standard deviation, +/- 3.6 months) after surgery. The survey included tests of cognitive performance, coping strategies, satisfaction with life, and a structured interview. We found a significant negative correlation between patient age and cognitive performance (P < 0.001), with a major decline beginning at the age of 55 years. Despite normal cognitive performance, 73% of younger patients (younger than 55 years) compared with 20% of older patients (P < 0.001) were not satisfied with life. As a major problem, 68% of younger patients described an inability to accept having this severe disease as a young person. Patients living as singles had a higher frequency of depressive coping (P < 0.05) and less satisfaction with life (P < 0.05). Comprehensive evaluation after meningioma surgery is required to prevent poor long-term results after apparently successful surgery. In our study, tests and structured interviews revealed different aspects, especially concerning patient age. Because demographic variables clearly influenced satisfaction with life, evaluation of quality of life must account for these factors to improve comparison of different studies. However, prospective studies with larger cohorts and control groups are required to prove our hypotheses.

PREDICTORS OF PERITUMORAL EDEMA AFTER STEREOTACTIC RADIOSURGERY OF SUPRATENTORIAL MENINGIOMAS

Anecdotal evidence suggests that radiosurgical ablation of parasagittal meningiomas may be associated with increased risk of subsequent edema. Potential predictors of postradiosurgical peritumoral edema, including parasagittal tumor location, tumor size, and treatment dose, were evaluated. We retrospectively reviewed records of 102 patients with 111 supratentorial meningiomas treated with CyberKnife (Accuray, Inc., Sunnyvale, CA) stereotactic radiosurgery (SRS). A median marginal dose of 18.0 Gy (range, 11.3-25.0 Gy) was delivered in 1 to 5 sessions (fractions). Potential predictors of posttreatment symptomatic edema were evaluated using Fisher's exact test. Of the 102 patients followed for a mean of 20.9 months (range, 6-77 mo), 15 (14.7%) developed symptomatic edema after SRS. Nine of 31 with parasagittal meningiomas (29.0%) and 6 of 80 with nonparasagittal supratentorial meningiomas (7.5%) developed symptomatic edema (P = 0.0053). Compared with patients with meningiomas in nonmidline supratentorial locations, patients with parasagittal meningiomas were more than 4 times as likely to develop symptomatic edema after SRS (odds ratio, 4.1; 95% confidence interval, 1.5-11.5). The 6-, 12-, and 18-month actuarial rates of symptomatic edema development were significantly greater for patients with parasagittal meningiomas than for patients with nonparasagittal meningiomas (17.8 versus 1.3%, 25.4 versus 5.8%, and 35.2 versus 7.8%, respectively). Patients with parasagittal meningiomas are at greater risk of developing peritumoral symptomatic edema after SRS. Close follow-up after SRS may be particularly important in such patients. These results highlight the need to pursue strategies that could decrease the incidence of postradiosurgical edema in patients with parasagittal meningioma.

Expression of vascular endothelial growth factor-A and mRNA stability factor HuR in human meningiomas

We studied the expression of vascular endothelial growth factor-A (VEGF-A) and mRNA stability factor HuR in 40 supratentorial meningiomas using RT-PCR, ELISA and immunohistochemistry, and analyzed their associations with the clinicopathological characteristics, including microvascular density (MVD), peritumoral brain edema (PTBE), histological subtypes and grades, and the performance of preoperative arterial embolization. Furthermore, we investigated the involvement of HuR in the upregulation of VEGF-A expression using primary meningioma cell cultures. The level of VEGF-A is elevated in meningiomas with PTBE and in higher grade meningiomas. Preoperative arterial embolization did not significantly increase the level of VEGF-A, but it did increase the expression of HuR in tumor tissues. HuR expression was correlated positively with VEGF-A expression in meningioma tissues. In in vitro experiments, hypoxia induced the upregulation of VEGF-A expression and the cytoplasmic translocation of HuR protein in meningioma cells, and inhibition of the cytoplasmic translocation of HuR reduced the upregulation of VEGF-A expression in meningioma cells. These findings suggest that the expression of VEGF-A relates to the development of PTBE with meningiomas and the histological grade, and that HuR is involved in the upregulation of VEGF-A expression in human meningiomas.

Meningioma without dural attachment: case report, classification, and review of the literature

Background The primary occurrences of meningiomas without attachment to the dura are rare. Clinical considerations and pathophysiologic mechanisms about these tumors have not been sufficiently explored, and a complete classification has not been accomplished. Case Description A 16-year-old adolescent boy presented with epileptic seizure for 9 years. Neurologic deficits were not found on admission. Magnetic resonance imaging revealed a 25 × 23-mm mass lesion without dural attachment located in the parietooccipital region. The tumor was iso-intense on T1-weighted and hyperintense on T2-weighted images, and became clearly and heterogenously enhanced with gadolinium. During surgery, a right parietooccipital craniotomy revealed the tumor was completely buried in the sulcus occipitalis anterior. Total removal of the tumor was accomplished. Histologic examination indicated that the lesion was an atypical meningioma. Conclusion According to sites of the tumor, supratentorial meningiomas without dural attachment are classified into 5 varieties, and posterior fossa meningiomas without dural attachment into 4 categories. Except for intraventricular ones, meningiomas without dural attachment predominantly occur in males. The average age is about 20 years younger than that of meningiomas in general. Fibroblastic meningiomas constitute the major subtype. Intraparenchymal or subcortical meningiomas should be considered as one type, which may arise from arachnoid cells of the pia mater within brain sulcus.

Correlation between the efferent venous drainage of the tumor and peritumoral edema in intracranial meningiomas: superselective angiographic analysis of 25 cases

The extent of peritumoral brain edema (PTBE) associated with meningiomas can be highly variable. The authors studied the correlation between the development of efferent venous drainage from the tumor and the degree of PTBE that occurs in intracranial meningiomas. Twenty-five patients with 27 intracranial supratentorial meningiomas were investigated to identify the correlation between the efferent venous drainage system of the tumor and peritumoral edema. The overall mean age of the patients was 54 years. Seventeen patients (68%) were female and eight (32%) were male. All patients underwent magnetic resonance imaging and digital subtraction angiography. In each meningioma, superselective angiography of the dominant feeding artery was performed, including the late venous phase to evaluate the development of the tumor's draining vein. An edema index (EI) was introduced to serve as an objective means by which to judge the extent of PTBE. Eleven meningiomas (41%), in which the mean EI was 0.14 +/- 0.10, clearly showed dominant draining veins originating from the tumor itself. In the other 16 meningiomas (59%), superselective angiography demonstrated no efferent venous drainage from the tumor, which could account for this group's mean EI value of 1.49 +/- 1.05 (p < 0.001). The current results suggest that hypoplasia of the efferent draining vein from the meningioma itself contributes to PTBE formation. The development of an efferent venous system mitigates against the formation of PTBE. Intratumoral venous congestion can be considered the main cause of PTBE in meningiomas.

Correlation of systemic protein S100β levels with postoperative indicators of neurological damage in supratentorial meningioma surgery

Correlation of systemic protein S100β levels with postoperative indicators of neurological damage in supratentorial meningioma surgery

Propionibacterium infection associated with bovine pericardium dural allograft

Propionibacteria are known to play a part in postneurosurgical infections, primarily those involving ventricular shunts. Nevertheless, little is known about the association between dural allografts and propionibacterium infections. Two patients underwent craniotomy for supratentorial meningiomas and each received a dural allograft. Both patients subsequently presented with delayed epidural fluid collections several weeks after surgery. Propionibacterium species was cultured in samples from both patients. The allografts were removed and the patients were treated with appropriate antibiotic agents; one patient underwent an interval craniectomy. Both patients demonstrated neuroimaging and clinical improvement after surgery and antiobiotic therapy. These cases demonstrate the association of propionibacterium infections with dural allografts. Furthermore, in patients with latent and indolent infections, Propionibacterium spp. should be suspected and treated appropriately.

Superatentorial intracerebral hemorrhage following infratentorial surgery

Supratentorial hematoma following infratentorial surgery is rare. We present two such patients with remote site supratentorial hematoma after posterior fossa surgery. In one patient, a supratentorial hematoma developed following surgery for an acoustic tumor. The supratentorial hematoma was located near where a supratentorial meningioma was excised five days before. No hematoma was seen on the immediate postoperative CT scan. In another patient there were two tumors, one in the pons and the other in the basal ganglia. This patient developed a basal ganglia hematoma following brain stem surgery. In both the patients, hematological profile revealed a coagulation abnormality following the posterior fossa surgery. Our first case stabilized conservative management, whereas the second required surgical evacuation of the hematoma. The differential diagnosis of declining level of conciousness after posterior fossa surgery must include supratentorial intracerebral hemorrhage and CT scan of the head is the diagnostic test of choice.

Diffusion-weighted imaging predicts postoperative persistence in meningioma patients with peritumoural abnormalities on magnetic resonance imaging.

While diffusion-weighted magnetic resonance imaging (MRI) has been used to study malignant brain tumours, this modality has not been used to study MRI abnormalities surrounding meningiomas. We examined intensity and apparent diffusion coefficient (ADC) on diffusion weighted imaging (DWI) for predicting postoperative persistence of MRI abnormalities surrounding meningiomas as well as characterizing the tumours. Of 36 meningiomas who underwent gross total resection, 27 (75%) showed hyperintensity on DWI at b=1100s/mm2. No atypical meningiomas were hypointense on DWI. Of the 26 supratentorial meningiomas, 18 (69.0%) had associated MRI abnormality. No significant correlation was seen between tumour intensity on DWI and existence of surrounding MRI abnormality. Meningothelial meningiomas showed a relatively low prevalence of MRI abnormalities surrounding tumour (30%). Of 11 patients who underwent sequential MRI, all MRI abnormalities surrounding tumour showing isointensity and high ADC on preoperative DWI disappeared after surgery (from 3 weeks to 10 months). All MRI abnormalities surrounding tumour showing hyperintensity and low ADC on preoperative DWI persisted on final follow-up MRI (from 6 months to 20 months). The postoperative course of MRI abnormality surrounding tumour might be predictable from the intensity and ADC on preoperative DWI. Since MRI abnormalities associated with meningiomas can cause preoperative neurologic deficits. We hypothesise that abnormalities with restricted diffusion will be more likely to be associated with a preoperative deficit, and more likely to remain after removal of the causative meningioma.