Surgical outcomes in large vestibular schwannomas: should cerebellopontine edema be considered in the grading systems?

Acta Neurochirurgica (2023) 165:1749–1755

Large (> 3 cm) vestibular schwannomas pose complexity in surgical management because of narrow working corridors and proximity to the cranial nerves, brainstem, and inner ear structures. With current vestibular schwannoma classifications limited in information regarding cerebellopontine edema, our retrospective series examined this radiographic feature relative to clinical outcomes and its possible role in preoperative scoring.

Methods Of 230 patients who underwent surgical resection of vestibular schwannoma (2014–2020), we identified 107 patients with Koos grades 3 or 4 tumors for radiographic assessment of edema in the middle cerebellar peduncle (MCP), brainstem, or both. Radiographic images were graded and patients grouped into Koos grades 3 or 4 or our proposed grade 5 with edema. Tumor volumes, radiographic features, clinical presentations, and clinical outcomes were evaluated.

Results The 107 patients included 22 patients with grade 3 tumors, 39 with grade 4, and 46 with grade 5. No statistical differences were noted among groups for demographic data or complication rates. Unlike grades 3 and 4 patients, grade 5 patients presented with worse hearing (p < 0.001), larger tumors (p < 0.001), lower rates of gross total resection (GTR), longer hospital stays, and higher rates of balance dysfunction.

Conclusion With edema detected in 43% of this cohort, special considerations are warranted for grade 5 vestibular schwannomas given the preoperative findings of worse hearing, lower GTR rates, longer hospital stays, and 96% who pursued postoperative balance therapy. We propose that grade 5 with edema offers a more nuanced interpretation of a radiographic feature that holds relevance to treatment selection and patient outcomes.

Peritumoral Edema/Tumor Volume Ratio: A Strong Survival Predictor for Posterior Fossa Metastases

Neurosurgery, Volume 85, Issue 1, July 2019, Pages 117–125

Twenty percent of all brain metastases (BM) occur in the posterior fossa (PF). Radiotherapy sometimes associated with surgical resection remains the therapeutic option, while Karnovsky performance status and graded prognostic assessment (GPA) are the best preoperative survival prognostic factors.

OBJECTIVE: To explore the prognostic role of peritumoral brain edema in the PF, which has never been explored though its role in supratentorial BM has been debated.

METHODS: A total of 120 patients diagnosed with PF metastasis who underwent surgical resection were included retrospectively in this analysis. Clinical data were retrieved from electronic patient medical files. The tumor volumes and their associated edema were calculated via manual delineation; subsequently the edema/tumor volume ratio was determined.

RESULTS: In multivariate analysis with Cox multivariate proportional hazard model, the edema to tumor volumes ratio (hazard ratio [HR]: 1.727, 95% confidence interval [CI] 1.427- 2.083; P < .0001) was identified as a new strong independent prognosis factor on overall survival (OS) whereas edema volume alone was not (P = .469). Moreover, BM complete resection (HR: 0.447, 95% CI 0.277-0.719; P < .001), low (0-1) World Health Organization status at diagnosis (HR: 2.109, 95% CI 1.481-3.015; P < .0001), high GPA class at diagnosis (HR: 1.77, 95% CI 0.9-2.9; P < .04), and postoperative brain irradiation (HR: 2.019, 95% CI 1.213-3.361; P < .007] were all confirmed as independent predictive factors for survival.

CONCLUSION: The edema/tumor ratio appears to greatly influence OS in patients suffering from PF metastases unlike the extent of edema alone. This easily determined as well as strong prognostic factor could be used as an interesting tool in clinical practice to help the management of these patients.

Brain invasion and the risk of seizures in patients with meningioma

J Neurosurg 130:789–796, 2019

Identification of risk factors for perioperative epilepsy remains crucial in the care of patients with meningioma. Moreover, associations of brain invasion with clinical and radiological variables have been largely unexplored. The authors hypothesized that invasion of the cortex and subsequent increased edema facilitate seizures, and they compared radiological data and perioperative seizures in patients with brain-invasive or noninvasive meningioma.

METHODS Correlations of brain invasion with tumor and edema volumes and preoperative and postoperative seizures were analyzed in univariate and multivariate analyses.

RESULTS Totals of 108 (61%) females and 68 (39%) males with a median age of 60 years and harboring totals of 92 (52%) grade I, 79 (45%) grade II, and 5 (3%) grade III tumors were included. Brain invasion was found in 38 (22%) patients and was absent in 138 (78%) patients. The tumors were located at the convexity in 72 (41%) patients, at the falx cerebri in 26 (15%), at the skull base in 69 (39%), in the posterior fossa in 7 (4%), and in the ventricle in 2 (1%); the median tumor and edema volumes were 13.73 cm3 (range 0.81–162.22 cm3) and 1.38 cm3 (range 0.00–355.80 cm3), respectively. As expected, edema volume increased with rising tumor volume (p < 0.001). Brain invasion was independent of tumor volume (p = 0.176) but strongly correlated with edema volume (p < 0.001). The mean edema volume in noninvasive tumors was 33.0 cm3, but in invasive tumors, it was 130.7 cm3 (p = 0.008). The frequency of preoperative seizures was independent of the patients’ age, sex, and tumor location; however, the frequency was 32% (n = 12) in patients with invasive meningioma and 15% (n = 21) in those with noninvasive meningioma (p = 0.033). In contrast, the probability of detecting brain invasion microscopically was increased more than 2-fold in patients with a history of preoperative seizures (OR 2.57, 95% CI 1.13–5.88; p = 0.025). In univariate analyses, the rate of preoperative seizures correlated slightly with tumor volume (p = 0.049) but strongly with edema volume (p = 0.014), whereas seizure semiology was found to be independent of brain invasion (p = 0.211). In multivariate analyses adjusted for age, sex, tumor location, tumor and edema volumes, and WHO grade, rising tumor volume (OR 1.02, 95% CI 1.00–1.03; p = 0.042) and especially brain invasion (OR 5.26, 95% CI 1.52–18.15; p = 0.009) were identified as independent predictors of preoperative seizures. Nine (5%) patients developed new seizures within a median follow-up time of 15 months after surgery. Development of postoperative epilepsy was independent of all clinical variables, including Simpson grade (p = 0.133), tumor location (p = 0.936), brain invasion (p = 0.408), and preoperative edema volume (p = 0.081), but was correlated with increasing preoperative tumor volume (p = 0.004). Postoperative seizure-free rates were similar among patients with invasive and those with noninvasive meningioma (p = 0.372).

CONCLUSIONS Brain invasion was identified as a new and strong predictor for preoperative, but not postoperative, seizures. Although also associated with increased peritumoral edema, seizures in patients with invasive meningioma might be facilitated substantially by cortical invasion itself. Consideration of seizures in consultations between the neurosurgeon and neuropathologist can improve the microscopic detection of brain invasion.

 

Prognostic Significance of Peritumoral Edema in Patients With Vestibular Schwannomas

Prognostic Significance of Peritumoral Edema in Patients With Vestibular Schwannomas

Neurosurgery 77:81–86, 2015

Peritumoral edema (PTE) in skull base meningiomas correlates to the absence of an arachnoid plane and difference in outcome. In vestibular schwannomas (VS), PTE and its significance for microsurgery and outcome have never been systematically evaluated.

OBJECTIVE: To evaluate whether PTE correlates with tumor characteristics, the presence of an arachnoid plane, and outcome.

METHODS: A retrospective study of the institutional database. PTE was evaluated on fluid-attenuated inversion recovery magnetic resonance images. Preoperative patient data and intraoperative tumor features (presence of tumor pseudocapsule, vascularity, degree of adhesion/invasion of the arachnoid) were noted. Outcome measures were completeness of removal, neurological outcome, and complication rate. These parameters in patients with PTE (group A) were correlated to those in matched series without edema (group B).

RESULTS: Thirty patients presented with PTE (5%). The mean VS size was 3.4 cm. No major differences in the degree of adhesion or presence of an arachnoid plane were found. VS with PTE were more frequently hypervascular (26.7% in group A vs 6.7% in group B). The presence of PTE in VS was not related to surgical radicality. VS with PTE had worse early postoperative facial nerve function, but at 12 months, there was no major difference. VS with PTE were prone to cause postoperative hemorrhages in the tumor bed.

CONCLUSION: PTE in VS does not correlate with the degree of tumor adhesion and the presence of an arachnoid dissection plane. The radicality of tumor removal and longterm functional outcome in patients with and without PTE was similar. VS with PTE are more vascular and prone to cause postoperative hemorrhages. Therefore, meticulous hemostasis is advisable.

Vascular Endothelial Growth Factor: The Major Factor for Tumor Neovascularization and Edema Formation in Meningioma Patients

Neurosurgery 67:1703–1708, 2010 DOI: 10.1227/NEU.0b013e3181fb801b

Peritumoral brain edema (PTBE) may be crucial in the clinical outcome of meningioma patients. The underlying pathogenetic key mechanism has so far not been determined. Sex, age, tumor size, location, involvement of other structures, or the histological appearance was not found to sufficiently explain PTBE formation in meningiomas.

OBJECTIVE: As PTBE formation is widely accepted to be vasogenic, we investigated the role of vascular endothelial growth factor (VEGF) and pial supplying vessels in a series of World Health Organization (WHO) grade I meningiomas.

METHODS: A total of 79 patients with WHO grade I meningiomas were immunohistochemically studied for VEGF and MIB-1. Pre- and postoperative magnetic resonance imaging including 3-dimensional reconstruction of 1.3-mm thick layers, with calculation of tumor and edema volume, was performed. Intraoperatively, the vascular supply and arachnoidal state were noted by the neurosurgeon.

RESULTS: VEGF was found to be exclusively confined to meningioma tumor cells. We identified 4 different patterns. VEGF and supplying pial vessels were found in 14 meningioma patients, pial vascular supply only in 3, VEGF expression only in 46, and neither VEGF expression nor supplying pial vessels in 16. Only the occurrence of both pial vascular supply and tumor VEGF expression was found to be correlated with PTBE formation (P , .002).

CONCLUSION: Our data suggest that VEGF may be crucial in angiogenesis and therefore indirectly in PTBE formation in World Health Organization grade I meningiomas

Exacerbation of Perihematomal Edema and Sterile Meningitis With Intraventricular Administration of Tissue Plasminogen Activator in Patients With Intracerebral Hemorrhage

Neurosurgery 66:631-638, 2010. DOI: 10.1227/01.NEU.0000367634.89384.4B

Intraventricular hemorrhage (IVH) is associated with a poor outcome. External ventricular drainage together with clot lysis through intrathecal tissue plasminogen activator (IT-tPA) has been proposed as a promising therapy. However, recent experimental work has implicated tissue plasminogen activator (tPA) in the pathogenesis of cerebral edema.

METHODS: We reviewed the records of all patients with IVH caused by primary supratentorial intracerebral hemorrhage who underwent external ventricular drainage without surgical evacuation between January 2001 and June 2008. Of these 30 patients, we identified 13 who received IT-tPA. The remaining 17 patients served as controls. Hemorrhage, edema volume, and IVH score were determined on admission and by follow-up computed tomographic scans for 96 hours after admission. Discharge outcome was evaluated using the modified Rankin Scale.

RESULTS: There were no significant differences between the treatment and controls in terms of age, Glasgow Coma Scale score, Graeb and LeRoux IVH scores, or intracerebral hemorrhage volume on admission. IT-tPA resulted in more rapid clearance of IVH as determined by the 96-hour decrease in both the Graeb IVH score (tPA, 3.00 ± .55; control, 1.00 ± 0.57; P = .05) and the LeRoux IVH score (tPA, 6.2 ± 0.80; control, 2.25 ± 1.32; P = .05). Patients treated with IT-tPA demonstrated significantly larger peak ratios of edema to intracerebral hemorrhage volume (1.24 ± 0.14 vs 0.70 ± 0.08 in controls; P = .002). Additionally, increased rates of sterile meningitis (46% vs 12%; P = .049) and a trend toward shunt dependence (38% vs 6%; P = .06) were observed in the tPA cohort. Nevertheless, no significant differences in outcome at discharge or length of hospital stay were observed between cohorts.

CONCLUSION: Although IT-tPA hastens the resolution of IVH, it may worsen perihematomal edema formation. Larger prospective studies are required to confirm these findings and to determine whether outcome is adversely affected by IT-tPA administration.