gms | German Medical Science

Objective: LITT (laser interstitial thermal therapy) for selective amygdalohippocampectomy (sAH is a minimally invasive surgical treatment option for temporal lobe epilepsies (Willie et al., 2014).

LITT-sAH regularly utilizes occipital entry points in order to lesion the amygdalohippocampal complex (AHC) with a single trajectory.

(Wu et al., 2019). In some cases the individual neuroanatomy of the patient does not permit to find a safe trajectory which allows for adaequate lesioning of the AHC.

A hippocampal malrotation (HIMAL), which according to the literature has no implications for epilepsy surgery (Tsai et al., 2016), constitutes such a constellation.

For these cases a combination of LITT and radiofrequency thermal ablation (RF-TA) utilizing multiple trajectories can represent a valuable alternative strategy.

Methods: We operated 20 epilepsy patients since march 2019 with LITT. Ten patients received a sAH. All procedures were carried out utilizing an MRI-compatible ceramic ring of a modified Riechert- Mundinger stereotactic system. This constellation enables the continuation of surgery after LITT with RF-lesioning maintaining the identical stereotactic space.

We could not identify save trajectories for 2 patients with ipsilateral HIMAL which could have enabled adequate lesioning. Therefore LITT-amygdalotomy was combined with RF-hippocampectomy. Both patients received one LITT- and three RF-lesions.

Results: There were no peri- or postoperative complications observed. After a follow-up of three months both patients were classified Engel Class 1.

Conclusion: HIMAL is a condition which can prevent LITT-sAH using a single trajectory. A combination treatment of LITT-amygdalotomy and RF- hippocampectomy potentially offers a safe treatment alternative in such cases. HIMAL therefore might be relevant in neurosurgical decision making in TLE. Larger cohorts and longer follow-ups are needed to confirm the observations made in our patients.