Abstract
Importance Stereoelectroencephalography (SEEG) is more frequently being used in the pre-surgical evaluation of children with focal epilepsy. Many factors affect the rate of identification of a definable seizure onset zone (SOZ) and subsequent seizure freedom following SEEG-guided epilepsy surgery, which have not been systematically examined in multi-centre studies.
Objectives Determine the rates and factors that predict (a) whether or not a definable putative SOZ was identified on SEEG and (b) subsequent seizure freedom following surgical intervention.
Design Retrospective cohort study
Setting Multicentre study involving 6 of 7 UK Children’s Epilepsy Surgery Service centres that perform paediatric SEEG in the UK.
Participants All children undergoing SEEG from 2014 - March 2019 were included. Demographic, non-invasive evaluation, SEEG and operative factors were collected retrospectively from patient records.
Main Outcomes The two main outcome measures were (a) whether or not a definable putative SOZ was identified on SEEG (binary yes/no outcome) and (b) subsequent seizure freedom following surgical intervention (Engel classification)
Findings One hundred and thirty-five patients underwent 139 SEEG explorations using a total of 1767 electrodes. A definable SOZ was identified in 117 patients (85.7%); odds of successfully finding a SOZ were 6.4x greater for non-motor seizures compared to motor seizures (p=0.02) and 3.6x more if ≥ 4 seizures were recorded during SEEG (p=0.03). Of 100 patients undergoing surgical treatment, 47 (47.0%) had an Engel class I outcome at a median follow-up of 1.3 years; the only factor associated with outcome was indication for SEEG (p=0.03). SEEG was safe with one (0.7%) haematoma requiring surgical evacuation and no long-term neurological deficits as a result of the procedure.
Conclusions and Relevance This large nationally representative cohort illustrates that, in these patients who may not have otherwise been offered resective surgery, SEEG-guided surgery can still achieve high rates of seizure freedom. Seizure semiology and the number of seizures recorded during SEEG are important factors in the identification of a definable SOZ and the indication for SEEG is an important factor in post-operative outcomes.
Competing Interest Statement
The authors have declared no competing interest.
Funding Statement
AC is supported by the Great Ormond Street Hospital Childrens Charity
Author Declarations
I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.
Yes
The details of the IRB/oversight body that provided approval or exemption for the research described are given below:
This retrospective study was waived from requiring formal ethical approval by the Institutional Review Board at Great Ormond Street Hospital. It was approved as a service evaluation by the Clinical Audit Department at GOSH (registration #1870). In addition, each centre registered the study as a retrospective service evaluation with their local research and development office.
All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.
Yes
I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).
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Footnotes
Funding: Aswin Chari is funded by a Great Ormond Street Hospital (GOSH)Children’s Charity Surgeon Scientist Fellowship. The work at GOSH was supported by the National Institute of Health Research (NIHR) – GOSH Biomedical Research Centre.
Changed the corresponding author details on title page to ensure that names are not self-extracted.
Data Availability
Individual patient-level data, including demographics, non-invasive evaluation, SEEG factors, operative factors and outcome measures are available from the corresponding author on request. The final decision to share the data remains at the discretion of the corresponding author and will be based on approval of a proposal for the use of the data.