大谷 啓介

BACKGROUND: Temporal encephaloceles (TEs) are increasingly recognized as epileptogenic lesions in drug-resistant temporal lobe epilepsy. However, endoscopic endonasal surgery performed primarily to resect epileptogenic lesions remains extremely rare, largely because defining the optimal extent of resection is challenging without direct electrophysiological confirmation. OBSERVATIONS: A 41-year-old right-handed man presented with drug-resistant focal impaired consciousness seizures. MRI revealed a right TE herniating into the lateral recess of the sphenoid sinus. Scalp EEG suggested seizure onset in the right anterior temporal region with no evidence of a widespread temporal epileptogenic network. Through an endoscopic endonasal transpterygoid approach, the encephalocele and adjacent temporal dura mater were exposed. Depth electrodes placed into the encephalocele and adjacent cortex demonstrated frequent spikes in both sites, confirming epileptogenicity. The encephalocele and a 7-mm margin of adjacent cortex were resected, followed by multilayer skull base reconstruction. The patient experienced no complications and remained seizure free for 48 months. LESSONS: Endonasal depth EEG enables direct confirmation of epileptogenicity in encephalocele-associated epilepsy and supports minimally invasive, tailored lesionectomy. In appropriately selected patients, particularly those without evidence of a widespread mesial temporal epileptogenic network, use of an endoscopic endonasal approach may avoid craniotomy while achieving durable seizure freedom. https://thejns.org/doi/10.3171/CASE25965.

Endoscopic third ventriculostomy (ETV) is a safe treatment option for chronic obstructive hydrocephalus. However, we encountered a case of chronic subdural hematoma (CSDH) with bilateral large hematoma volumes after ETV for chronic obstructive hydrocephalus. We herein report a rare complication of ETV. The patient was a 53-year-old woman who had been diagnosed with asymptomatic ventricular enlargement with aqueductal stenosis 5 years previously. However, over the course of 5 years, her gait and cognitive function gradually declined. ETV was administered to relieve symptoms. Head Magnetic resonance imaging performed 1 week after ETV indicated bilateral subdural hygroma. Three weeks after ETV, she presented with headache and left incomplete paralysis, and head Computed tomography (CT) demonstrated bilateral CSDH with a large volume hematoma. Burr-hole evacuation and drainage of the bilateral CSDH were performed, after which the symptoms resolved. However, 7 weeks after ETV, she again presented with headache and incomplete right paralysis, and CT revealed bilateral CSDH re-enlargement. After the second burr-hole evacuation and drainage of bilateral CSDH, her symptoms resolved. The bilateral CSDH continued to shrink following the second hematoma evacuation surgery and completely disappeared on CT scan performed 3 months after ETV. Ventricular enlargement due to chronic obstructive hydrocephalus stretches the brain mantle for several years. This long-term stretching may have diminished the brain compliance and led to the development, growth, and recurrence of CSDH. In ETV for chronic obstructive hydrocephalus, surgeons should consider the risk of postoperative CSDH with a high hematoma volume and tendency to recur.