Surgical Outcomes and Impacts in Lennox-Gastaut Syndrome Clarified

Sandi K. Lam, MD, MPH

A recently published systematic review and meta-analysis evaluated a number of surgical procedures for patients with Lennox-Gastaut syndrome (LGS) and their impact on seizure control, antiepileptic drug (AED) usage, quality of life (QoL) behavior, cognition, prognostic factors, and complications.

Senior author Sandi K. Lam, MD, MPH, pediatric neurosurgeon, Ann and Robert H. Lurie Children’s Hospital of Chicago, and colleagues compared outcomes of vagus nerve stimulation (VNS), corpus callosotomy (CC), and resective surgery (RS). Forty studies including 892 patients with LGS met the selection criteria, with 19 reporting on CC, 17 on VNS, 4 on RS, 2 on RS + CC, 1 on CC + VNS, and 1 on deep brain stimulation (DBS).

The researchers found a seizure reduction rate of 74.1% (95% CI, 64.5-83.7) for CC compared to 54.6% (95% CI, 42.9-66.3) for VNS, which was significantly different (P <.001). RS seizure reduction was 88.9% (95% CI 66.1–99.7). The difference between CC and VNS seizure rates persisted across each of the 3 postprocedural follow-up periods analyzed.

Many VNS patients reported alertness improvements, and most had no major complications. Notably, the meta-analysis did not find a difference in seizure reduction rate for VNS from the 0 to 6-month follow-up period to the 2-or-more-year follow-up period.

"Resective surgery continues to show remarkable seizure reduction rate and QOL improvements for LGS patients with localized seizure foci, and it has proven to be the standard of care for any patient with identifiable epileptogenic zone, including those with LGS,” Lam et al concluded.

Thirty-one studies assessing 33 intervention groups commented on usage of AEDs before surgery, during the study period, and/or after surgery. All told, none of the VNS studies reported an overall increase in AEDs after surgery, 4 reported an overall decrease in AED (23.5%), 9 reported very little or no change (53%), and 4 reported an unspecified change (23.5%). Comparatively, of the CC studies, 2 reported an overall increase in AEDs (18%), 5 an overall decrease in AED (45%), 3 very little or no change (27%), and 1 an unspecified change. Among the other interventions, 1 RS study reported a notable decrease in AEDs after surgery, whereas the others reported very little change.

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Researchers found that higher or longer durations of stimulation in VNS were associated with better outcomes in a few studies. For CC, patients with a greater extent of callosotomy tended to have better seizure outcomes. In 1 particular study, CC was less effective for myoclonic seizures compared to other seizure types. Among RS studies, shorter duration of preoperative epilepsy and hemispherectomy were associated with better seizure outcomes.

For VNS, there was no reduction in QoL, cognition, or behavior. Patients were reportedly more alert, had higher mental age, demonstrated better verbal communication, memory and mood. However, in rare instances there was a decline in mood as well as reported behavioral problems.

Patients with LGS who underwent CC had no reduction in intelligence quotient (IQ) or attention span and had improvements in IQ, cognition, and attention. They also saw improvements in QoL, behavior, and parental satisfaction. QoL decline was rare in this treated group. There was no difference in social functioning, as well as no changes in IQ, QoL, memory, or behavior for those who opted for RS. Memory decrease was found in a minority group of patients with LGS.

"CC may be a better palliative measure than VNS in regard to seizure reduction rate, but providers and caregivers should consider that VNS may provide a similar or higher level of QOL improvement with lower risk of procedure-related adverse events. Resective surgery [with] CC and DBS also show promise for a small subset of LGS patients,” the authors wrote.

Epilepsy surgery can not only be effective but cost efficient too for patients with refractory forms of epilepsy. Lara Jehi, MD, and colleagues published a study in 2020 that evaluated the cost of epilepsy surgery and surgical evaluation and found both to be cost effective for eligible patients with drug-resistant temporal lobe epilepsy. Jehi, who is also the chief research officer and an epilepsy specialist at Cleveland Clinic, detailed why her results could ultimately have a big impact on those who are fearful of opting for epilepsy surgery or even a surgical evaluation.

REFERENCE

Thirunavu V, Du R, Wu JY, Berg AT, Lam SK. The role of surgery in the management of Lennox-Gastaut syndrome: a systematic review and meta-analysis of the clinical evidence. Epilepsia. Published online February 24, 2021. doi: 10.1111/epi.16851