Introduction: • To analyze the available literature on radiosurgery for epilepsy, evaluating efficacy of seizure control, complications and long-term effects.
• To classify selected studies according to the Oxford Evidence-Based Medicine Classification system so as to determine strength of evidence.
Methods: • A systematic review was performed of peer-reviewed articles on radiosurgery for epilepsy using search terms “epilepsy” and “radiosurgery” in Pubmed and SCI.
• Working through 365 hits, 82 relevant papers were selected and reviewed.
• These 82 papers were classified using the Oxford Evidence-Based Medicine classification system and weighed according to the strengths of design and trial execution.
Results: • The 82 articles were categorized into 3 Level I (RCT), 30 Level II (cohort), 3 Level III (case control), 22 Level IV (case reports), 17 Level V (expert opinion) and 7 experimental studies.
• Across the evidence-classes radiosurgery was seen as effective for controlling seizures in 2/3rd of the patients.
• Most commonly treated epilepsy syndromes included medial temporal lobe epilepsy and gelastic epilepsy in hypothalamic hamartoma.
• Seizure remission took an average of 12 to 24 months but was durable once achieved.
• No significant neuro-psychological deficits were seen while radio-necrosis occurring in some patients was easily treated with steroids in most instances.
• Serious complications were rare. No paper elucidated the mechanism by which sublethal radiosurgery affects neuronal function.
Conclusions: Radiosurgery for epilepsy is a feasible, less invasive alternative to open surgical resection. Studies available at this time show comparable results in terms of outcome and efficacy with a low side-effect profile. Both basic experimental and multi-centre randomized control trials are needed to develop evidence-based strategies and physiological targeting for radiosurgery. Nevertheless, radiosurgery currently qualifies as a grade B recommendation for treating epilepsy.
Patient Care: Presented data will help in appropriate patient selection for radiosurgical treatment of epilepsy, help neurosurgeons to discuss with patients about effects of stereotactic radiation on epilepsy disorders with evidential authority and propel more research in deriving newer radiosurgical treatment strategies for epilepsy.
Learning Objectives: By the conclusion of this session participants should be able to:
1) Understand key hypothesis that explain the anti-epileptic action of focussed radiation,
2) Identify epilepsy syndromes commonly treated with radiosurgery,
3) Discuss in small groups available literature on radiosurgical treatment of epilepsy.