Dario J. Englot, Mitchel S. Berger, Nicholas M. Barbaro and Edward F. Chang
Seizures are the most frequent presenting symptom in patients with low-grade gliomas (LGGs), and significantly influence quality of life if they are uncontrolled. Achieving freedom from seizures is of utmost importance in surgical planning, but the factors associated with seizure control remain incompletely understood.
The authors performed a systematic literature review of seizure outcomes after resection of LGGs causing seizures, examining 773 patients across 20 published series. Rates of seizure freedom were stratified across 7 variables: patient age, tumor location, preoperative seizure control with medication, seizure semiology, epilepsy duration, extent of resection, and the use of intraoperative electrocorticography (ECoG).
Gross-total resection was most predictive of complete seizure freedom, when compared with subtotal resection (OR 3.41, 95% CI 2.36–4.93). Other predictors of seizure freedom included preoperative seizure control on antiepileptic medication (OR 2.12, 95% CI 1.33–3.38) and duration of seizures of ≤ 1 year (OR 1.85, 95% CI 1.22–2.79). Patients with simple partial seizure semiology achieved seizure freedom less often than those with complex partial, generalized, or mixed seizure types (OR 0.46, 95% CI 0.26–0.80). No significant differences in seizure outcome were observed between adults versus children, patients with temporal lobe versus extratemporal tumors, or with the use of intraoperative ECoG.
Seizure control is one of the most important considerations in planning surgery for low-grade brain tumors. Gross-total resection is a critical factor in achieving seizure freedom.
Dario J. Englot, Stephen T. Magill, Seunggu J. Han, Edward F. Chang, Mitchel S. Berger and Michael W. McDermott
Meningioma is the most common benign intracranial tumor, and patients with supratentorial meningioma frequently suffer from seizures. The rates and predictors of seizures in patients with meningioma have been significantly under-studied, even in comparison with other brain tumor types. Improved strategies for the prediction, treatment, and prevention of seizures in patients with meningioma is an important goal, because tumor-related epilepsy significantly impacts patient quality of life.
The authors performed a systematic review of PubMed for manuscripts published between January 1980 and September 2014, examining rates of pre- and postoperative seizures in supratentorial meningioma, and evaluating potential predictors of seizures with separate meta-analyses.
The authors identified 39 observational case series for inclusion in the study, but no controlled trials. Preoperative seizures were observed in 29.2% of 4709 patients with supratentorial meningioma, and were significantly predicted by male sex (OR 1.74, 95% CI 1.30–2.34); an absence of headache (OR 1.77, 95% CI 1.04–3.25); peritumoral edema (OR 7.48, 95% CI 6.13–9.47); and non–skull base location (OR 1.77, 95% CI 1.04–3.25). After surgery, seizure freedom was achieved in 69.3% of 703 patients with preoperative epilepsy, and was more than twice as likely in those without peritumoral edema, although an insufficient number of studies were available for formal meta-analysis of this association. Of 1085 individuals without preoperative epilepsy who underwent resection, new postoperative seizures were seen in 12.3% of patients. No difference in the rate of new postoperative seizures was observed with or without perioperative prophylactic anticonvulsants.
Seizures are common in supratentorial meningioma, particularly in tumors associated with brain edema, and seizure freedom is a critical treatment goal. Favorable seizure control can be achieved with resection, but evidence does not support routine use of prophylactic anticonvulsants in patients without seizures. Limitations associated with systematic review and meta-analysis should be considered when interpreting these results.
John D. Rolston, Dario J. Englot, Arnau Benet, Jing Li, Soonmee Cha and Mitchel S. Berger
The dominant hemisphere frontal operculum may contain critical speech and language pathways, and due to these properties, patients with tumors of the opercular region may be at higher risk for postoperative speech dysfunction. However, the likelihood of incurring temporary or permanent language dysfunction is unknown.
The authors retrospectively analyzed their cohort of patients with frontal gliomas to identify those tumors that predominantly involved the dominant frontal operculum. Each tumor was classified as involving the pars orbitalis, pars triangularis, pars opercularis, or a combination of some or all of these areas. The authors then identified and compared characteristics between those patients experiencing transient or permanent speech deficits, as opposed to those with no language dysfunction.
Forty-three patients were identified for inclusion in this analysis. Transient deficits occurred in 12 patients (27.9%), while 4 patients (9.8%) had persistent deficits involving language. Individuals with preoperative language deficits and patients with seizures characterized by speech dysfunction appear to be at the highest risk to develop a deficit (relative risks 3.09 and 1.75, respectively). No patient with a tumor involving the pars orbitalis experienced a persistent deficit.
Resection of gliomas is widely recognized as a critical element of improved outcome. Given the low rate of language morbidity reported in this group of patients, resection of gliomas within the dominant frontal operculum is well-tolerated with acceptable morbidity and, in this particular location, should not be a deterrent in the overall management of these tumors.
Matthew J. Shepard and W. Jeffrey Elias