Corpus Callosotomy (cc) Is An Effective Treatment For Lennox-gastaut Syndrome

Corpus callosotomy (CC) is an effective treatment for Lennox-Gastaut syndrome (LGS) associated with iso-dicentric chromosome 15 syndrome (idic 15 syndrome). Christopher Todd Anderson, Sarah Schmitt, Peter Crino, Gordon Baltuch Penn Epilepsy Center, University of Pennsylvania, Department of Neurology, Philadelphia, PA Rationale: Iso-dicentric chromosome 15 syndrome (idic 15) is unique genetic syndrome with: 1) mental retardation, 2) minor facial dysmorphism, 3) autism, 4) cardiac dysrhythmia & sudden cardiac death, and 5) epilepsy (often LGS). Although many with idic 15 have atonic seizures, to our knowledge, CC has not been reported for these patients. The issue of complete vs. staged CC in idic15-LGS has also not been addressed. Methods: A 25 year-old woman with idic 15 developed intractable epilepsy at 18. She had complexpartial seizures, generalized convulsions, tonic & atonic seizures with falls. Epilepsy was progressive and she suffered up to 10 atonic seizures and convulsions daily. She had recurrent tachycardia not related to seizures. Failed “AEDs” included phenytoin, carbamazepine, valproic acid (VPA), topiramate (TPM), zonisamide, lamotrigine, and levetiracetam (LEV). Vagal nerve stimulation (output current 1.25, signal on-time 30 seconds/ off-time 180 sec) for 1 year failed to produce a noticeable benefit. Pre-operative EEG revealed disorganization, diffuse slowing, spike-wave and polyspike-and-slowwave discharges and atonic seizures with generalized voltage attenuation and evolving fast frequency activity. Preoperative MRI was normal. ECHO was normal, ECGs revealed sinus tachycardia. CC was performed under general anesthesia. She was not tachycardic during surgery (but postoperatively, HR was140 BPM). A stereotactically-guided 3/4 CC was performed. She remained on 3 “AEDs” before, during, and after surgery. Results: Post-operatively, she was mute and profoundly hypokinetic, unable to follow commands, would not visually track, had eye closure apraxia , and required comprehensive care including a PEG. This persisted for more than 4 weeks. Post-operative EEG revealed diffuse slowing, and rare parietal sharp waves. She underwent inpatient rehabilitation. Within 6 weeks, she began to walk and speak. Finally, more than 2 months after surgery, she was more alert than at her prior baseline (without medication change). Over approximately 1 year of follow-up, approximately 10 atonic seizures had been witnessed, and up to 10 brief staring spells had been witnessed, while no generalized convulsions had occurred. Conclusion: “Complete” CC is an appropriate treatment for LGS in idic 15. There are informal reports of anterior 1/3 CC of idic-15 LGS with quick recovery but without robust seizure abatement. Although the risk of cardiac death during surgery should be mitigated (pre-operative cardiac evaluation should be performed), our patient had no worsening of her tachycardia related to the procedure. CC for patients with idic 15 should likely be an aggressive single-staged procedure. Prolonged recovery should be expected (weeks to months).

Pre-operative EEG.

Post-operative EEG.