| Type of Surgery | Target Area | Indication |
|---|---|---|
| Anterior Temporal Lobectomy (ATL) | Anterior 3–5 cm of temporal lobe including amygdala and part of hippocampus | Mesial TLE with hippocampal sclerosis |
| Selective Amygdalohippocampectomy (SAH) | Amygdala and hippocampus | Mesial TLE with cortical sparing |
| Temporal Lesionectomy | Visible lesions (tumors, dysplasias) | Lesional epilepsy |
| Extrahippocampal Temporal Lobe Epilepsy Surgery | Lateral (neocortical) temporal structures | Neocortical TLE |
| Multiple Subpial Transection (MST) | Surgical transections without tissue removal | Adjunct for eloquent cortex cases |
| Approach | Technique Description | Common Uses |
|---|---|---|
| Transsylvian | Via Sylvian fissure to mesial structures | SAH |
| Subtemporal | Below temporal lobe, cortex-sparing | Alternative SAH approach |
| Transcortical | Through temporal cortex to mesial areas | ATL, lesionectomy |
- Curative Surgery (e.g., ATL, SAH, lesionectomy) - Palliative Surgery (e.g., MST)
- Laser Interstitial Thermal Therapy (LITT): MRI-guided minimally invasive ablation. - Responsive Neurostimulation (RNS): Device-based targeted electrical stimulation.
Temporal lobe epilepsy surgery is classified based on anatomical target, approach, and intent. Technique choice depends on seizure focus, lesion presence, and cognitive preservation goals.
Patients who had a keyhole approach for temporal lobe epilepsy with over 2 years follow-up were compared with all patients who had selective amygdalohippocampectomy performed in a non-keyhole fashion over the same time period. Rates of seizure freedom were comparable in the 17 patients with keyhole surgery and the 34 individuals who had a non-keyhole approach. However, patients treated with keyhole surgery were discharged from the hospital earlier than non-keyhole patients (p=0.04), and with a shorter operative time (p=0.0001). The restricted keyhole surgical exposure has not limited the ability to perform surgery for temporal lobe epilepsy with favorable results on reducing the seizure tendency, and patients may be benefited by a minimal access technique with a more rapid recovery from surgery 1).
Yang et al. described operations they were performed through a 6-cm vertical linear incision and a low 2.5-cm keyhole craniotomy at the anterior squamous temporal bone. Resection of the anterior-most portions of the middle and inferior temporal gyri provided a cylinder-like corridor to the mesial temporal lobe. Identification of the temporal horn through a basal approach was followed by resection of the amygdala, uncus, and hippocampus-parahippocampal gyrus.
A 9-year series included 683 patients with a minimum follow-up duration of 2 years. Surgery times were short (range, 1 h 35 min to 2 h 30 min). Only a small percentage of patients had complications (1.76 %), and the rate of Engel Class I seizure-free outcome was 87 %. No overt speech problems or visual field deficits were identified. Compared with the most popular conventional trans-middle temporal gyrus approach, this technique can make the operation easier, safer, and less traumatic to functional lateral neocortex 2).
see Magnetic resonance image-guided laser interstitial thermal therapy for epilepsy.
Separately, Laser interstitial thermotherapy (LITT) has found a role in the treatment of temporal lobe epilepsy because it allows the creation of a precise lesion along the amygdala and hippocampus. Although seizure control rates appear to be somewhat inferior to open temporal lobectomy and selective amygdalohippocampectomy, the procedure is generally well tolerated, and because of its minimally invasive nature, it has the potential to reach a large segment of epilepsy patients who would be good surgical candidates but have shied away from open surgery.
The advantage of selective amygdalohippocampectomy (SAH) over anterior temporal lobectomy (ATL) for the treatment of temporal lobe epilepsy (TLE) remains controversial. Because ATL is more extensive and involves the lateral and medial parts of the temporal lobe, it may be predicted that its impact on memory is more important than SAH, which involves resection of medial temporal structures only. However, several studies do not support this assumption. Possible explanations include task-specific factors such as the extent of semantic and syntactic information to be memorized and failure to control for main confounders 3).