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Isolation of dominant seizure foci by multiple subpial transections
A A Patil1, R Andrews, R Torkelson
1Section of Neurosurgery, University of Nebraska Medical Center, Omaha, USA.
Abstract:
Dominant seizure foci (DSF) are seizure foci that do not respond to multiple subpial transections (MST). DSF were isolated in 15/31 patients who underwent MST in the past 6 years. These patients had MST over both hemispheres (6 patients) or over multiple lobes of one hemisphere (9 patients). DSF measured 0.5-1 cm in diameter and numbered 1-4 (in each patient). Their excision resulted in dramatic improvement in EEG over wide areas of the cortex. The longest postoperative follow-up is 67 months, with a median of 21 months. Nine of 15 patients are free of seizures, 3/15 have rare seizures, 2/15 have > 90% reduction in seizure frequency, and 1/15 has > 70% reduction in seizure frequency with improvement in motor and speech functions. In summary, DSF are resistant to MST and influence the electrical activity of the surrounding cortex. MST combined with excision of DSF resulted in good seizure control in this series, which included patients with multilobar and bihemispheric seizure foci.
Insights
Dominant seizure foci (DSF) resistant to multiple subpial transections (MST) were surgically excised. This approach led to significant seizure reduction or complete seizure freedom in 14 out of 15 patients.
Area of Science:
- Neurosurgery
- Epilepsy Surgery
- Clinical Neurology
Background:
- Dominant seizure foci (DSF) are identified as seizure generators unresponsive to multiple subpial transections (MST).
- DSF can persist despite extensive cortical transection, impacting treatment outcomes in epilepsy surgery.
Purpose of the Study:
- To evaluate the efficacy of surgical excision for dominant seizure foci (DSF) that are resistant to multiple subpial transections (MST).
- To assess seizure control and functional outcomes following DSF excision in patients with medically intractable epilepsy.
Main Methods:
- Retrospective analysis of 15 patients who underwent MST and subsequently had DSF identified and excised over a 6-year period.
- DSF were located in patients with either bihemispheric or multilobar involvement.
- Surgical excision of DSF was performed, followed by EEG monitoring and clinical outcome assessment.
Main Results:
- DSF, measuring 0.5-1 cm, were excised in 15 patients, leading to widespread EEG improvement.
- Postoperative follow-up (median 21 months) showed 9/15 patients became seizure-free.
- An additional 5/15 patients experienced significant seizure reduction (>70% frequency reduction), with one showing improved motor and speech functions.
Conclusions:
- Dominant seizure foci (DSF) are refractory to MST but amenable to surgical excision.
- Combining MST with DSF excision offers a viable strategy for achieving substantial seizure control in complex epilepsy cases.
- This combined approach demonstrates significant potential for improving quality of life in patients with multilobar and bihemispheric epilepsy.