Intracranial, Intraaxial, Space‐Occupying Lesions in Patients with Intractable Partial Seizures: An Anatomoclinical, Neuropsychological, and Surgical Correlation

Abstract

Fifty of approximately 250 patients evaluated for intractable partial seizures were shown to have a space-occupying lesion detected with radiographs and/or neuroimaging. Twenty-eight males and 22 females had a mean age at seizure onset of 13 years and a mean duration of seizures of 11 years. All patients had closed-circuit television with EEG monitoring and complete neurologic and neuropsychological assessment. Findings were correlated with lesion location and surgical data. Twenty-seven lesions (54%) were located in the temporal lobe. Thirty-five lesions (70%) were neoplastic. All patients with temporal lobe lesions had complex partial seizures, as did 74% of patients with extratemporal lesions. A good correlation between clinical seizure characteristics and lesion localization was found with the temporal, occipital, and frontal lesions but not with the parietal lesions. Sixty-six percent of patients had focal interictal EEG findings. Lateralization corresponded to the side of the lesion in 64% and was localized to the region of the lesion in 30%. Lateralized ictal EEGs occurred in 58% of patients, corresponding with the side of the lesion in all but one patient. Abnormal findings on neuropsychological testing were congruent with lesion lateralization in 56% of patients and were localized to the region in 26%. Thirty-nine of 47 patients who underwent a subtotal lobectomy to include the lesion are seizure-free after greater than or equal to 1 year of follow-up, and five others are markedly improved.

Clinical characteristics and surgical outcome of patients with temporal lobe tumors and epilepsy

“…Different surgical approaches have been used varying from simple lesionectomy to total lobectomy including the hyppocampus and amygdala. In some series as ours the inclusion of the mesial temporal structures didn't promote a better prognosis 7,14,15 while in others extensive resections implied in control of the seizures 3,16,17 . Studies have identified incomplete tumor resections or tumor recurrences as a important cause of a poor postoperative seizure control 8,[18][19][20] .…”

“…20% of patients who undergo surgical treatment of temporal lobe medically refractory epilepsy [2][3][4] . Due of the benign nature of these lesions, recurrent, often refractory epilepsy, epileptic seizures are the usual presentation of these lesions, mass effect signs or bleeding are characteristically absent in this setting.…”

Temporal Lobe Epilepsy: When Are Invasive Recordings Needed?

“…Surface EEG is characterized by a higher incidence of interictal spikes compared to HS (89). Several authors have noted also that in patients with lesions interictal spikes may be more widespread (89,90) and may even occur bilaterally independent (91). These features are therefore not necessarily a contradiction to resection of the lesion.…”

“…This is supported by good outcomes in this patient group after lesionectomy. In a study published by Boon et al (90) Invasive recordings may be required in patients with a single lesion if seizure patterns recorded by surface EEG raise doubts that the lesion is indeed causing the epilepsy. Schiller et al (80) showed that 20 of 22 (90%) lesional patients with nonlocalizable surface EEG findings, but congruent intracerebral nionitoring and MRI results, were seizure-free after surgery.…”

Glioma-Associated Epilepsy

“…When the peritumoural tissue removal is not satisfactory, postoperative seizure control remains effectively unchanged [107,108,9,106,109,58]. Image-guided stereotactic lesional resection achieves a longterm seizure-free outcome in 57% of cases [108] whereas the inclusion of peritumoural tissues in the resection volume raised this metric beyond 80% [110,111]. The realization that the peritumoural environment is critical in the promotion of most epileptic manifestations has prompted the use of intraoperative electrocorticography in cases of low grade gliomas, in particular, to increase the likelihood of capturing those responsible cortical areas in the resection volume [112][113][114][115][116].…”