Epilepsy surgery in tuberous sclerosis: An overview of neurosurgical concerns in a low-income country

Abstract

BACKGROUND AND IMPORTANCE: Oftentimes, patients with early-onset seizures fail to respond well to initial medication. Mental retardation and early onset seizures are linked. There is growing evidence that early seizure control may adversely affect the development of cognitive skills and social behaviour in children with Tuberous sclerosis complex. According to recent studies, despite the challenges associated with epilepsy surgery planning for TSC patients, a substantial number of patients (>60%) can be seizure-free if the right clinical candidates are selected and evaluated. MATERIALS AND METHODS: Using revised diagnostic criteria, we report the series of 10 patients diagnosed with TSC between 2014 and 2021. A referral was made to the department of pediatric neurosurgery at Shiraz University of medical sciences. Besides a thorough history and physical examination, a comprehensive neuropsychological assessment was conducted along with a high resolution (HR) EEG, seizure recording, and long-term video EEG. A neuropsychological test was performed at 6 months, 12 months, and 24 months after surgery. An MRI was also performed at 3 months. Seizure progression was classified according to the Engel classification at each time point. RESULTS: At the time of seizure onset, age ranged from 0.1 to 13 years, with the median age being 0.8 years. On average, each surgical candidate had epileptogenic foci located on their right side (in the temporal region of 3 patients, the frontal region of 4 patients, and the parieto-occipital region of 3 patients). A follow-up of 12-60 months revealed three patients reaching Engel class 1. The seizure frequency of the remaining 7 patients improved significantly by at least 50% during the first year of follow-up. CONCLUSION: There have been several series published in the last few decades documenting good seizure results following epilepsy surgery in TSC. Over the past several decades, the perspective has changed, and different studies demonstrate that even if several tubers are present in the same area of the brain, the epileptogenic zone and one or two tubers almost always overlap, and this is especially true when partial seizures are present. TSC patients with DRE, multiple seizure types with early onset, multiple cortical tubers, and more than one epileptogenicity should consider epilepsy surgery as there is still no empirical evidence that these patients will have poor outcomes.