Benet, Arnau MD, PhD; Suzuki, Yosuke MD; Noda, Kosumo MD; Tanikawa, Rokuya MD Author Information

Medically refractory hemispheric epilepsy is a devastating disease with significant lifetime costs and social burden. Functional hemispherotomy is a highly effective treatment for hemispheric epilepsy but is associated with significant complication rates. Percutaneous hemispherotomy through laser interstitial thermal therapy (LITT) based on morphological MRI has been recently described in a single patient but not replicated in the literature. To describe the first 2 cases of tractography-guided interstitial laser hemispherotomy and their short-term outcomes. Two 11-year-old male patients with medically refractory epilepsy secondary to perinatal large vessel infarcts were referred for hemispherotomy. Both patients underwent multitrajectory LITT to disconnect the remaining pathological hemisphere, using tractography to define targets and assess structural outcomes. Both cases had minor complication of small intraventricular/subarachnoid hemorrhage not requiring additional intervention. Both patients remain seizure-free at all follow-up visits. LITT hemispherotomy can produce seizure freedom with short hospitalization and recovery. Tractography allows surgical planning to be tailored according to individual patient anatomy, which often is distorted in perinatal stroke. Minimally invasive procedures offer the greatest potential for seizure freedom without the risks of an open hemispherotomy.

Triggered electromyography (tEMG) is an intraoperative neuromonitoring technique used to assess pedicle screw placement during instrumented fusion procedures. Although spinal anesthesia is a safe alternative to general anesthesia in patients undergoing lumbar fusion, its use may potentially block conduction of triggered action potentials or may require higher threshold currents to elicit myotomal responses when using tEMG. Given the broad utilization of tEMG for confirmation of pedicle screw placement, adoption of spinal anesthesia may be hindered by limited studies of its use alongside tEMG. To investigate whether spinal anesthesia affects the efficacy of tEMG, we compare the baseline spinal nerve thresholds during lumbar fusion procedures under general vs spinal anesthesia. Twenty-three consecutive patients (12 general and 11 spinal) undergoing single-level transforaminal lumbar interbody fusion were included in the study. Baseline nerve threshold was determined through direct stimulation of the spinal nerve using tEMG. Baseline spinal nerve threshold did not differ between the general and spinal anesthesia cohorts (3.25 ± 1.14 vs 3.64 ± 2.16 mA, respectively; P = .949). General and spinal anesthesia cohorts did not differ by age, body mass index, American Society of Anesthesiologists score status, or surgical indication. We report that tEMG for pedicle screw placement can be safely and effectively used in procedures under spinal anesthesia. The baseline nerve threshold required to illicit a myotomal response did not differ between patients under general or spinal anesthesia. This preliminary finding suggests that spinal anesthetic blockade does not contraindicate the use of tEMG for neuromonitoring during pedicle screw placement.

Graffeo, Christopher S. MD, MS; Zavala, Baltazar MD, PhD; Cole, Tyler S. MD; Srinivasan, Visish M. MD; Lawton, Michael T. MD Author Information

*Department of Neurological Surgery, Lois Pope Life Center, University of Miami Miller School of Medicine, Miami, Florida, USA; ‡Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA Correspondence: Aria M. Jamshidi, MD, Department of Neurological Surgery, Lois Pope Life Center, University of Miami Miller School of Medicine, 1095 NW 14th Terrace (D4-6), Miami, FL33136, USA. Email: [email protected]

Nair, Prakash MS, MCh*; Honavalli Murali, Sanjay MS, MCh*; Harihara Venkat, Easwer MCh*; Poyuran, Rajalakshmi MBBS, MD, PDF‡ Author Information

Vigo, Vera MD; Asmaro, Karam P. MD; Nunez, Maximiliano A. MD; Bobrow, Aidan BS; Dodd, Robert L. MD, PhD; Desai, Atman MD; Fernandez-Miranda, Juan C. MD Author Information

Stereotactic laser amygdalohippocampotomy (SLAH) using laser interstitial thermal therapy is a minimally invasive surgery used to treat mesial temporal lobe epilepsy. It uses laser probes inserted through occipital and temporo-occipital trajectories to ablate the hippocampus and amygdala. However, these trajectories are limited in their ability to ablate the superior amygdala and entorhinal cortex (ERC). We present a trajectory through the middle frontal gyrus as an alternative to the temporo-occipital trajectory, which provides more complete ablation of the amygdala and anterior ERC through a single pass. A 70-year-old woman with seizures characterized by fear were localized to the left superomedial amygdala on intracranial electroencephalography. They developed after resection of a left temporal arteriovenous malformation and were refractory to medication. Her age and prior craniotomy made open resection less desirable. A frontal and occipital SLAH achieved Engel 1a at 1-year follow-up without decline in neuropsychological performance scores. Typical SLAH uses trajectories that have limited ability to ablate the superior and medial amygdala and ERC in a single passage. A combined approach using an occipital and frontal trajectory allows more complete ablation of the amygdala, hippocampus, and ERC.