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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Epilepsy surgery | 2/2 | https://en.wikipedia.org/wiki/Epilepsy_surgery | reference | science, encyclopedia | 2026-05-05T09:19:31.127122+00:00 | kb-cron |
== Temporal lobe resection == Temporal lobe resection acts as a treatment option for patients with temporal lobe epilepsy, or those whose seizure focus is in the temporal lobe. Temporal lobe seizures are the most common type (approximately 30% of diagnoses) of seizures for teens and young adults. The procedure involves resecting, or cutting away, brain tissue within the region of the temporal lobe in order to remove the seizure focus. Specific evaluation for temporal lobe resection requires convergent clinical, MRI, and EEG data in order to precisely pinpoint the focal area and boundaries of the focal area. The surgery has produced successful outcomes, controlling seizures in as much as 70 percent of temporal lobe epilepsy patients. Follow-up studies suggest that the procedure also has produced positive long-term effects that illustrate 63 percent of patients still remaining seizure-free. Although the procedure produces positive outcomes for patients regarding seizure control, it can also produce negative outcomes such as memory impairment, visual disturbance, and cognitive dysfunction. Hemispheric dominance can determine the likelihood of certain complications of surgery in the temporal lobe; for the majority of right-handed people, the left hemisphere is dominant and is associated with the brain's language centers (most notably Wernicke's area) and the right (non-dominant) hemisphere is associated with memory and learning of non verbal information such as vision. Thus, temporal lobe resection of the dominant hemisphere often causes verbal memory impairment while resection of the non-dominant hemisphere often causes visual memory impairment. Important structures implicated in temporal lobectomies include the auditory cortex, hippocampus, Wernicke's area, and amygdala; the latter three broadly affecting memory, language, and emotion, respectively. The hippocampus, amygdala, and parahippocampal gyrus are collectively termed the mesial temporal structures and are frequently targeted for resection in epilepsy. Types of temporal lobectomy include anterior temporal lobectomy (ATL) and selective amygdalohippocampectomy (SAH). The ATL resection is the most common technique where the lateral and polar cortex are removed along with the aforementioned mesial temporal structures as well as the posterior part depending on which hemisphere the epileptogenic zone lies. The most common complication after ATL is a defect in vision known as a homonymous superior quadrantanopia, wherein the upper quarter field of vision on both eyes is altered, known as the "pie in the sky defect", with a frequency from 1.5% to 22%. ATL surgery resection encompasses the amygdala, hippocampus as well as surrounding tissue or neocortex whereas SAH is more targeted to the former two structures to be as minimally disruptive as possible. The SAH approach goes through a space on the lateral side of the brain known as the Sylvian fissure to reach the amygdala and hippocampus which are deeper in the middle of the brain. These structures may also be targeted through the middle temporal gyrus, below the Sylvian fissure, to avoid the visual pathways that course near the top of the temporal lobe. The decision between ATL and SAH should include a multidisciplinary team involving an epileptologist and neurosurgeon and tailored to each patient's specific case. Both have varying rates of seizure freedom depending on how well the epileptogenic zone is localized. One meta-analysis found that there is no significant difference in seizure freedom but visual complications after surgery were less frequent in SAH.
== Extratemporal resection == Extratemporal lobe resection acts as a treatment option for patients with extratemporal epilepsy, or epilepsy patients whose seizure focus is outside of the temporal lobe, and stems from either the occipital lobes, parietal lobe, frontal lobe, or in multiple lobes. The evaluation for the procedure often requires more than clinical, MRI, and EEG convergence due to the variability of the seizure focus. Along with additional imaging techniques such as PET and SPECT, invasive studies may be needed to pinpoint the seizure focus. The efficacy of extratemporal lobe resection generally is less than resection of the temporal lobe. For example, in frontal lobe resections seizure freedom has been achieved in 38-44 percent of patients.
== Tumor Resection == If a benign or malignant brain tumor is suspected to be the cause of seizure activity, surgical removal of the tumor may be indicated. The approach and technique is case-dependent. One study of supratentorial brain tumors in children less observed a dramatic reduction in the severity and frequency of seizures at one and four year follow-up. See also Brain tumors.
== Laser Interstitial Thermal Therapy (LITT) == LITT is a minimally invasive technique under imaging guidance (typically MRI) where a small hole is drilled through the skull (a Burr hole) and a precise laser targets structures that are causing seizures, known as laser ablation. Ablative procedures are appropriate options for patients who otherwise would not be good surgical candidates due to other medical problems or specific anatomical reasons that would make targeting their epilepsy difficult with a traditional surgery. Outcomes for each type of surgery vary widely depending on seizure localization, epilepsy specifics, and surgeon approach. Given that this is a new technique, more research into comparing outcomes is necessary but preliminary studies suggest lower seizure freedom. See also ablative brain surgery.
== See also == Engel classification Anticonvulsant Temporal lobe Temporal lobe epilepsy Epilepsy syndromes Rasmussen Encephalitis Sturge–Weber syndrome Hippocampal sclerosis
== References ==