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Open access

Presurgical language mapping in bilingual children using transcranial magnetic stimulation: illustrative case

Savannah K. Gibbs, Stephen Fulton, Basanagoud Mudigoudar, Frederick A. Boop, and Shalini Narayana

BACKGROUND

Presurgical mapping of eloquent cortex in young patients undergoing neurosurgery is critical but presents challenges unique to the pediatric population, including motion artifact, noncompliance, and sedation requirements. Furthermore, as bilingualism in children increases, functional mapping of more than one language is becoming increasingly critical. Transcranial magnetic stimulation (TMS), a noninvasive brain stimulation technique, is well suited to evaluate language areas in children since it does not require the patient to remain still during mapping.

OBSERVATIONS

A 13-year-old bilingual male with glioblastoma multiforme involving the left parietal lobe and deep occipital white matter underwent preoperative language mapping using magnetic resonance imaging-guided TMS. Language-specific cortices were successfully identified in both hemispheres. TMS findings aided in discussing with the family the risks of postsurgical deficits of tumor resection; postoperatively, the patient had intact bilingual speech and was referred for chemotherapy and radiation.

LESSONS

The authors’ findings add to the evolving case for preoperative dual language mapping in bilingual neurosurgical candidates. The authors illustrate the feasibility and utility of TMS as a noninvasive functional mapping tool in this child. TMS is safe, effective, and can be used for preoperative mapping of language cortex in bilingual children to aid in surgical planning and discussion with families.

Open access

Contralateral insular epileptogenic hub causing seizure relapse after opercular focal cortical dysplasia surgery and response to radiofrequency thermocoagulation: illustrative case

Pushkaran Jayapaul, Shameer Aslam, Bindhu Mangalath Rajamma, Siby Gopinath, and Ashok Pillai

BACKGROUND

The reevaluation and management of seizure relapse following resective surgery in magnetic resonance imaging (MRI)-negative pharmacoresistant epilepsy remains a significant challenge.

OBSERVATIONS

A 25-year-old right-handed male with medically refractory epilepsy presented with nonlocalizing electroencephalography (EEG) and MRI. Stereo-EEG (SEEG) implantation based on semiology and positron emission tomography imaging revealed a left frontal opercular focus with rapid bilateral insular ictal synchrony. The initial epileptogenic zone was resected and pathologically proven to be type 2A focal cortical dysplasia (FCD). Seizure relapse after 9 months was eventually reinvestigated, and repeat SEEG revealed a secondary epileptogenic focus in the contralateral insula. A novel technique of volumetric stereotactic radiofrequency ablation (vRFA) was utilized for the right insular focus, following which, the patient remains seizure-free for 20 months. He suffered a transient bilateral opercular syndrome following the second intervention that eventually resolved.

LESSONS

The authors present clinical evidence to suggest epileptogenic nodes distant from the primary focus as a mechanism for seizure relapse following FCD surgery and the importance of bilateral insular SEEG coverage. The authors also describe a novel technique of minimally invasive vRFA that allows ablation of a larger volume of cerebral cortex when compared to conventional bedside SEEG electrode thermocoagulation.

Open access

Complete section of the left vagus nerve does not preclude the efficacy of vagus nerve stimulation: illustrative case

Alice Noris, Paolo Roncon, Simone Peraio, Anna Zicca, Matteo Lenge, Andrea Di Rita, Lorenzo Genitori, and Flavio Giordano

BACKGROUND

Vagus nerve stimulation (VNS) represents a valid therapeutic option for patients with medically intractable seizures who are not candidates for epilepsy surgery. Even when complete section of the nerve occurs, stimulation applied cranially to the involved nerve segment does not preclude the efficacy of VNS. Complete vagus nerve section with neuroma causing definitive left vocal cord palsy has never been previously reported in the literature.

OBSERVATIONS

Eight years after VNS implant, the patient experienced worsening of seizures; the interrogation of the generator revealed high impedance requiring surgical revision. On surgical exploration, complete left vagus nerve section and a neuroma were found. Vocal cord atrophy was found at immediate postoperative laryngeal inspection as a confirmation of a longstanding lesion. Both of these events might have been caused by direct nerve injury during VNS surgery, and they presented in a delayed fashion.

LESSONS

VNS surgery may be complicated by direct damage to the left vagus nerve, resulting in permanent neurological deficits. A complete section of the nerve also enables an efficacious stimulation if applied cranially to the involved segment. Laryngeal examination should be routinely performed before each VNS surgery to rule out preexisting vocal cord dysfunction.

Open access

Papillary glioneuronal tumor growing slowly for 26 years: illustrative case

Kazuma Shinno, Yoshiki Arakawa, Sachiko Minamiguchi, Yukinori Terada, Masahiro Tanji, Yohei Mineharu, Takayuki Kikuchi, Hironori Haga, and Susumu Miyamoto

BACKGROUND

Papillary glioneuronal tumors (PGNTs) are classified as a type of World Health Organization grade I mixed neuronal-glial tumor. Most PGNTs involve cystic formations with mural nodules and solid components in the cerebral hemispheres, and PGNTs occur mainly in young adults. The long-term prognosis of PGNTs remains unclear.

OBSERVATIONS

A 38-year-old male had been diagnosed with an arachnoid cyst associated with epilepsy in a local hospital. The initial magnetic resonance imaging (MRI) study showed the tumor as a heterogeneously enhanced nodule in the left postcentral gyrus. Subsequent MRI studies showed slow growth of the tumor for 26 years. He underwent gross total resection to control his epilepsy. The histopathological findings revealed pseudopapillary structures involving hyalinized blood vessels with a single or pseudostratified layer of cuboidal glial cells with round nuclei and scant cytoplasm. At the periphery of the lesion, Rosenthal fibers and acidophilic granule bodies were observed in the gliotic brain tissue. Immunohistochemically, some interpapillary cells were positive for NeuN. On the basis of these findings, the tumor was diagnosed as a PGNT.

LESSONS

This PGNT showed slow growth for 26 years. When recognizing a slowly growing tumor in the cerebral hemispheres of relatively young people that is associated with epileptic seizures, PGNT should be considered as a differential diagnosis.

Open access

Surgical strategy for refractory epilepsy secondary to porencephaly: ictal SPECT may obviate the need for intracranial electroencephalography. Patient series

Naoki Ichikawa, Naotaka Usui, Akihiko Kondo, Takayasu Tottori, Tokito Yamaguchi, Hirowo Omatsu, Takayoshi Koike, Hiroko Ikeda, Katsumi Imai, and Yukitoshi Takahashi

BACKGROUND

Surgical treatment of intractable epilepsy caused by porencephaly can be difficult because of poorly localizing or lateralizing electroclinical findings. The authors aimed to determine whether noninvasive evaluations are sufficient in these patients.

OBSERVATIONS

Eleven patients were included in this study. The porencephalic cyst was in the left middle cerebral artery (MCA) area in 9 patients, the left posterior cerebral artery area in 1 patient, and the bilateral MCA area in 1 patient. Interictal electroencephalography (EEG) revealed multiregional, bilateral, interictal epileptiform discharges in 5 of 11 patients. In 6 of 10 patients whose seizures were recorded, the ictal EEG was nonlateralizing. Nine patients underwent ictal single-photon emission computed tomography (SPECT), which revealed lateralized hyperperfusion in 8 of 9 cases. Fluorodeoxyglucose positron emission tomography (FDG-PET) was useful for identifying the functional deficit zone. No patient had intracranial EEG. The procedure performed was hemispherotomy in 7 patients, posterior quadrant disconnection in 3 patients, and occipital disconnection in 1 patient. A favorable seizure outcome was achieved in 10 of 11 patients without the onset of new neurological deficits.

LESSONS

Ictal SPECT was useful for confirming the side of seizure origin when electroclinical findings were inconclusive. Thorough noninvasive evaluations, including FDG-PET and ictal SPECT, enabled curative surgery without intracranial EEG. Seizure and functional outcomes were favorable.

Open access

The utility of diffusion tractography for speech preservation in laser ablation of the dominant insula: illustrative case

Timothy J. Kaufmann, Vance T. Lehman, Lily C. Wong-Kisiel, Panagiotis Kerezoudis, and Kai J. Miller

BACKGROUND

Open surgical treatment of insular epilepsy holds particular risk of injury to middle cerebral artery branches, the operculum (through retraction), and adjacent language-related white matter tracts in the language-dominant hemisphere. Magnetic resonance imaging (MRI)-guided laser interstitial thermal therapy (LITT) is a surgical alternative that allows precise lesioning with potentially less operative risk. The authors presented the case of a 13-year-old girl with intractable, MRI-negative, left (dominant hemisphere) insular epilepsy that was treated with LITT. Diffusion tensor imaging (DTI) tractography was used to aid full posterior insular lesioning in the region of stereo electroencephalography–determined seizure onset while avoiding thermal injury to the language-related superior longitudinal fasciculus (SLF)/arcuate fasciculus (AF) and inferior fronto-occipital fasciculus (IFOF).

OBSERVATIONS

DTI tractography was used successfully in planning insular LITT and facilitated a robust insular ablation with sharp margins at the interfaces with the SLF/AF and IFOF. These tracts were spared, and no neurological deficits were induced through LITT.

LESSONS

Although it is technically demanding and has important limitations that must be understood, clinically available DTI tractography adds precision and confidence to insular laser ablation when used to protect important language-related white matter tracts.

Open access

Facial palsy after temporal lobectomy for epilepsy: illustrative cases

Émile Lemoine, Sami Obaid, Laurent Létourneau-Guillon, and Alain Bouthillier

BACKGROUND

Facial palsy is a rare, unexpected complication of temporal lobectomy (TL) for intractable epilepsy. Even without direct manipulation, the facial nerve fibers may be at risk of injury during supratentorial surgery, including TL.

OBSERVATIONS

The authors presented two cases of facial palsy after unremarkable TL. In the first case, the palsy appeared in a delayed fashion and completely resolved within weeks. In the second case, facial nerve dysfunction was observed immediately after surgery, followed by progressive recovery over 2 years. The second patient had a dehiscence of the roof of the petrous bone overlying the geniculate ganglion, which put the facial nerve at risk of bipolar coagulation thermal injury.

LESSONS

Two major mechanisms could explain the loss of facial nerve function after TL: surgery-related indirect inflammation of the nerve resulting in herpesvirus reactivation and delayed dysfunction (Bell’s palsy) or indirect thermal damage to the geniculate ganglion through a dehiscent petrous roof.

Open access

Superficial siderosis of the central nervous system with epilepsy originating from traumatic cervical injury: illustrative case

Liqing Xu, Changwei Yuan, Yingjin Wang, Shengli Shen, and Hongzhou Duan

BACKGROUND

Superficial siderosis of the central nervous system (SSCNS) is a rare condition that results from hemosiderin deposition in the brain, brainstem, cerebellum, and spinal cord as a result of chronic, repeated, and recurrent subarachnoid hemorrhage. SSCNS that originates in the spinal cord is rarely reported, and epilepsy as a manifestation of such a case has not been reported before.

OBSERVATIONS

The authors reported a rare case of SSCNS with epilepsy originating from traumatic cervical injury and presented a literature review of all reported SSCNS cases that originated in the spine. The patient was a 29-year-old man with a 16-year history of progressive headache accompanied by seizures, ataxia, and sensorineural hearing loss. He had experienced a traumatic cervical injury at age 7. Magnetic resonance imaging revealed a characteristic hypointense rim around the pons and cervical spinal cord on susceptibility-weighted imaging scans. Cerebrospinal fluid examination during a headache episode confirmed subarachnoid hemorrhage and increased intracranial pressure. Surgical exploration revealed a C6 dural defect with bone spurs inserted into the dura mater. After the patient underwent dura mater repair and shunt implantation, his symptoms disappeared completely except for hearing loss.

LESSONS

This rare case indicated that symptomatic epilepsy followed by SSCNS can be eliminated by complete repair of the cervical dura mater.

Open access

Removal of malformation in cerebral proliferative angiopathy: illustrative case

Gwang Yoon Choi, Hyuk Jai Choi, Jin Pyeong Jeon, Jin Seo Yang, Suk-Hyung Kang, and Yong-Jun Cho

BACKGROUND

Cerebral proliferative angiopathy (CPA) is a rare vascular disorder distinct from arteriovenous malformation. Because of the disorder’s rarity, there is still a controversy on the most promising treatment method for CPA. However, several meta-analysis articles suggest indirect vascularization such as encephalo-duro-arterio-synangiosis as an effective way of treating symptoms that are medically uncontrolled.

OBSERVATIONS

The authors describe a case of an 11-year-old boy with this disease, who had epilepsy that was intractable despite conservative management. The patient recovered from his symptoms after the vascular malformation was surgically removed. This is the first reported case of surgical removal in CPA.

LESSONS

Although further investigation on the best treatment for CPA is needed, the authors believe surgical intervention may also be an effective treatment modality when a patient presents with persisting symptoms.

Open access

Epileptogenic zone localization using intraoperative gamma oscillation regularity analysis in epilepsy surgery for cavernomas: patient series

Yosuke Sato, Yoshihito Tsuji, Yuta Kawauchi, Kazuki Iizuka, Yusuke Kobayashi, Ryo Irie, Tatsuya Sugiyama, and Tohru Mizutani

BACKGROUND

In epilepsy surgery for cavernoma with intractable focal epilepsy, removal of the cavernoma with its surrounding hemosiderin deposition and other extended epileptogenic zone has been shown to improve postsurgical seizures. However, there has been no significant association between such an epileptogenic zone and intraoperative electrocorticography (ECoG) findings. The authors recently demonstrated that high regular gamma oscillation (30–70 Hz) regularity (GOR) significantly correlates with epileptogenicity.

OBSERVATIONS

The authors evaluated the utility of intraoperative GOR analysis in epilepsy surgery for cavernomas. The authors also analyzed intraoperative ECoG data from 6 patients with cavernomas. The GOR was calculated using a sample entropy algorithm. In 4 patients, the GOR was significantly high in the area with the pathological hemosiderin deposition. In 2 patients with temporal cavernoma, the GOR was significantly high in both the hippocampus and the area with the pathological hemosiderin deposition. ECoG showed no obvious epileptic waveforms in 3 patients, whereas extensive spikes were observed in 3 patients. All patients underwent cavernoma removal plus resection of the area with significantly high GOR. The 2 patients with temporal cavernomas underwent additional hippocampal transection. All patients were seizure free after surgery.

LESSONS

The high GOR may be a novel intraoperative marker of the epileptogenic zone in epilepsy surgery for cavernomas.