Stereoelectroencephalography for Epilepsy Presurgical Assessment: A Nationwide Survey of Evolution of Practice in Australia.

BACKGROUND AND OBJECTIVES

Stereoelectroencephalography (SEEG) is increasingly used worldwide for epilepsy presurgical evaluation. A data-driven view of SEEG practice evolution is lacking for any world region. We aimed to perform a nationwide survey of SEEG use in Australian adult epilepsy centers. We predicted that the proportion of nonlesional MRI cases, number of electrodes, and radiofrequency thermocoagulation (RF-TC) use would increase over time.

METHODS

All epilepsy centers in Australia undertaking SEEG in patients older than 16 years at any time were invited to participate in a nationwide survey. Data were retrospectively and/or prospectively collected on patient demographics and SEEG exploration. Descriptive statistics were used.

RESULTS

A total of 281 SEEG explorations were performed in 8 centers from 2012 until 2023, 278 of which (99%) are reported here. A definite epileptogenic MRI lesion was present in 30.6% with no overall significant growth in the proportion of nonlesional cases (χ² [1, N = 278] = 0.067, = 0.79), although this varied per center. Patients identifying as Indigenous Australians comprised 1.6% of this national SEEG survey vs an estimated national indigenous population of 3.8%. The median number of electrodes increased from 8 in 2012 to 15 in 2023. A total of 174 patients (62.6%) were offered resective surgery after SEEG. Surgery was performed with 1-year follow-up in 114, of whom 72.8% were seizure-free at the last follow-up. The presence/absence of an MRI lesion was not associated with postoperative seizure-free outcomes (χ² [1, N = 114] = 0.06, = 0.80). RF-TC use differed between centers and evolved, with a crossover to the majority use of RF-TC occurring 5 years after regulatory approval.

DISCUSSION

This comprehensive nationwide and regional survey of SEEG practice comprises full ascertainment of all centers and allows analysis of changes in practice over time. Whole cohort results show a high proportion of nonlesional MRI cases achieving satisfactory surgical outcomes and evolution to increased RF-TC use. Indigenous access to SEEG seems to be lower than expected, consistent with broader health care access issues for this population group. Nationwide collaboration on SEEG data provides a basis for analysis of practice at the individual center and state and national levels to optimize health care planning and sharing of expertise.