Endoscopic Hemispherotomy for Nonatrophic Rasmussen's Encephalopathy.

BACKGROUND: Hemispheric disconnection represents a challenging and major epilepsy surgical procedure. This procedure in experienced hands offers excellent results in terms of seizure outcomes, especially for hemispheric pathologies such as Rasmussen's encephalitis, hemispheric dysplasias, hemimegalencephaly. The technique of hemispherotomy has witnessed various modifications over the years, beginning from anatomical hemispherectomy to the current era of minimally invasive functional hemispheric disconnections. OBJECTIVE: This study aimed to describe the technique of performing endoscopic vertical hemispherotomy using interhemispheric corridor developed by the senior author. MATERIALS AND METHODS: A 12-year-old girl with seizure onset at the age of 10 years presented with an aura of fear and nausea followed by tonic deviation of eyes to the right and blinking with speech arrest. There were tonic-clonic movements of the right-sided limbs along with ictal spitting and occasional deviation of the angle of mouth to the right. The patient had loss of awareness for the event along with postictal confusion lasting few minutes. RESULTS: Video electroencephalography (VEEG) revealed left parietocentral and left temporal localization. Serial magnetic resonance imaging (MRI) brain over 3 years revealed progressive left hemispheric changes suggestive of Rasmussen's encephalitis. The patient underwent left-sided endoscopic hemispherotomy. At 2 years follow-up, the patient is seizure-free (ILAE [International League Against Epilepsy] Class 1). CONCLUSION: Endoscopic hemispherotomy using the interhemispheric approach is an elegant, minimally invasive, reproducible, safe, and efficacious technique.

Epilepsy surgery in COVID times-a unique conundrum.

The COVID-19 pandemic has forced hospitals to prioritize admissions. Epilepsy surgeries have been postponed at most centers. As the pandemic continues with no definite end in sight in the near future, the question arises until when such patients should be denied appropriate treatment. A 12-year-old child with left-sided Rasmussen's encephalitis with drug refractory epilepsy (DRE) presented at the height of the pandemic, with worsening of seizure frequency from 4-5/day to 20/day, with new-onset epilepsia partialis continua. She demonstrated features of progressive cognitive decline. The pros and cons of operating during the pandemic were discussed with the parents by a multidisciplinary team. She underwent endoscopic left hemispherotomy. Postoperatively she became seizure free but developed hospital-acquired mild COVID infection for which she was treated accordingly. Chosen cases of severe DRE, as the one illustrated above, who are deemed to benefit from surgery by a multidisciplinary team of physicians, should be re-categorized into the most severe class of patients and scheduled for surgery as soon as possible. The risk benefit ratio of the seizures being mitigated by surgery on one hand and possibility of acquiring COVID infection during hospital stay has to be balanced and a decision made accordingly.

Posterior quadrant disconnection for sub-hemispheric drug refractory epilepsy.

The posterior quadratic epilepsy (PQE) is a form of a multilobar epilepsy, involving the temporal-parietal and occipital lobes. Basically, epilepsies with localized networks to the posterior temporal, posterior parietal, and occipital lobes can benefit from this type of surgery. Gliosis due to perinatal insult and cortical dysplasis and angiomas in Sturge Weber syndrome involving the PQ have often been cited in the literature as the etiology for PQE. However, before considering surgery, it is important to localize the epileptogenic focus through a complete pre operative work up involving; EEG (Electro-Encephalo-Graphy), video EEG, single photon emission computed tomography (SPECT), positron emission tomography (PET), and magneto encephalography (MEG). Historically, these pathologies were dealt with multi-lobar resections, which were associated with high morbidity and mortality, owing to blood loss, especially in young children, hydrocephalus, and hemosiderosis. Based on the theory of networks involved in epileptogenesis, the concept of disconnection in epilepsy surgery was introduced. Delalande and colleagues, described the technique of hemispheric disconnection (functional hemispherectomy) for pathologies like: hemimegalencephaly, rasmussens encephalitis involving the entire hemisphere. The technique has evolved with time, moving towards minimally invasive endoscopic vertical hemispherotomy, described by Chandra and colleagues.[1],[2] The posterior quadrant disconnection (PQD) evolved as a tailored disconnection on similar lines as hemispherotomy, for managing refractory epilepsy arising from the posterior quadrant.[3] The technique and principles involved in the PQD surgery are similar to the those of peri-insular hemispherotomy and has been described in the literature by few authors.[3],[4],[5],[6] The technique of performing PQD will be described here in a step-wise fashion with illustrations supplemented by a surgical video.