Outcomes of surgically and non-surgically managed temporal encephalocoeles in the context of drug-resistant temporal lobe epilepsy: A retrospective single-centre case series

Temporal encephalocoeles are a recognised cause of drug-resistant temporal lobe epilepsy (TLE), with uncertain associations to epileptogenesis and an unclear optimal management approach. Operative management, particularly resective temporal lobe surgery, has been proposed, but outcomes and decision-making criteria remain debated. This study aims to evaluate the outcomes of surgically and non-surgically managed patients with temporal encephalocoeles in the context of drug-resistant TLE, focusing on seizure freedom rates, postoperative complications and factors influencing management decisions. A retrospective, single-centre study was conducted based on all adult TLE patients with temporal encephalocoeles encountered between March 2017 and August 2023. Patients were classified into three groups: those discussed at an epilepsy surgery multidisciplinary team (MDT) meeting and managed surgically (surgical group), those discussed at an MDT and managed non-surgically (non-surgical group) and those radiologically identified by reporting neuroradiologists but not discussed at MDT (radiologically diagnosed group). Clinical, electrophysiological, radiological and surgical data were compared across the groups, including radiological features of raised intracranial pressure (ICP) that have been postulated as a cause for temporal encephaloceles. We included 24 adult patients with temporal encephalocoeles: eight in the surgical group, eight in the non-surgical group and eight in the radiologically diagnosed group. The mean age at diagnosis was 39.3 ± 13.6 years and clinical features were comparable across groups. Operative management was decided by an experienced epilepsy surgery MDT, involving resection of the anterior temporal pole with (4/8, 50 %) or without (50 %) mesial temporal structures, resulted in a seizure freedom rate of 87.5 %. In contrast, no patient in the non-surgical or radiologically diagnosed groups achieved seizure freedom (0 %). Postoperative complications included one patient who developed hydrocephalus and required a ventriculoperitoneal shunt, and another who developed a pseudomeningocoele. Radiological markers of raised ICP were broadly similar across the groups, with the exception of increased optic nerve sheath diameter in the non-surgical group (p = 0.032). Our study demonstrates that excellent post-operative outcomes are achievable with temporal lobe resections. A standardised presurgical evaluation pathway and management protocol are essential to ensure timely identification of temporal encephalocoeles on imaging, facilitating preoperative planning and optimising surgical outcomes. CSF hydrodynamic disturbances may occur after surgery for encephaloceles and individualised evaluation is therefore crucial to select the most appropriate management approach.