From the Journals

Better epilepsy outcomes with stereoelectroencephalography versus subdural electrode



Robotic stereoelectroencephalography for the localization of seizures in epilepsy is associated with less procedural morbidity, such as infection and hemorrhage, and better outcomes, compared with subdural electrode implantation.

A paper published in JAMA Neurology detailed the results of a retrospective cohort study of the outcomes of 239 patients with medically intractable epilepsy, 121 of whom underwent stereoelectroencephalography (SEEG) and 139 underwent subdural electrode (SDE) implantation.

The authors noted a significant difference between the two groups in complication rates. There were seven symptomatic hemorrhagic sequelae and three infections related to SDE implantation, and in one of these cases the patient suffered long-term neurologic consequences.

In contrast, there were no symptomatic complications in the SEEG cohort, although two patients were found to have small asymptomatic subdural hematomas that were spotted on CT scans.

Patients in the implantation group also received significantly more narcotics and had a much higher rate of perioperative blood transfusions (13.7% vs. 0.8%, P less than .001), compared with those in the SEEG group.

The study also looked at epilepsy outcomes in the two groups. Significantly more of the patients who had subdural electrodes underwent resection or ablative surgery with laser interstitial thermal therapy, compared with the patients who had SEEG (91.4% vs. 74.4%, P less than .001).

“Thus, the SEEG and SDE cohorts were significantly different in the proportions of cases that were lesional, suggesting that these modalities were used to evaluate somewhat different populations, although the same group of physicians at the same center managed and referred these cases,” wrote Nitin Tandon, MD, from the University of Texas, Houston, and his coauthors. “However, this shift in the patient pool would be expected to bias outcomes against SEEG, because these patients generally have less favorable outcomes.”

Yet the authors saw that a significantly greater proportion of the SEEG patients were free of disabling seizures, compared with the SDE implant group at 6 months (83.9% vs. 66.1%) and 1 year (76% vs. 54.6%) after resection.

To account for the difference between the two groups in the proportion of cases that were lesional, the authors conducted a subgroup analysis of patients with abnormalities on imaging. Again, they saw that a significantly greater proportion of the SEEG patients achieved good outcomes at 6 months and 1 year, compared with the electrode group.

While subdural electrodes have long been the standard approach for delineating epileptogenic zones, the authors wrote that SEEG offers improved coverage and precise targeting of deeper structures. “In addition, the ability of the SEEG method to map distributed epileptic networks involved in epileptic activity has been hypothesized to be responsible for improved outcomes in patients with epilepsy that is difficult to localize.”

They also commented that, in their institution, they saw much greater patient tolerance for SEEG and slightly better outcomes in those patients who underwent resection or ablation.

One author reported a position with a company specializing in outpatient clinical neurophysiological testing services. No other conflicts of interest were reported.

SOURCE: Tandon N et al. JAMA Neurol. 2019 Mar 4. doi: 10.1001/jamaneurol.2019.0098.

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