Long term outcome of temporal lobe epilepsy surgery: analyses of 140 consecutive patients

Abstract

Objective: To analyse the long term results of temporal lobe epilepsy surgery in a national epilepsy surgery centre for adults, and to evaluate preoperative factors predicting a good postoperative outcome on long term follow up. Methods: Longitudinal follow up of 140 consecutive adult patients operated on for drug resistant temporal lobe epilepsy. Results: 46% of patients with unilateral temporal lobe epilepsy became seizure-free, 10% had only postoperative auras, and 15% had rare seizures on follow up for (mean (SD)) 5.4 (2.6) years, range 0.25 to 10.5 years. The best outcome was after introduction of a standardised magnetic resonance (MR) imaging protocol : in unilateral temporal lobe epilepsy, 52% of patients became seizure-free, 7% had only postoperative auras, and 17% had rare seizures (median follow up 3.8 years, range 0.25 to 6.5 years); in palliative cases (incomplete removal of focus), a reduction in seizures of at least 80% was achieved in 71% of cases (median follow up 3.1 years, range 1.1 to 6.8 years). Most seizure relapses (86%) occurred within one year of the operation, and outcome at one year did not differ from the long term outcome. Unilateral hippocampal atrophy with or without temporal cortical atrophy on qualitative MR imaging (p < 0.001, odds ratio (OR) 5.2, 95% confidence interval (CI) 2.0 to 13.7), other unitemporal structural lesions on qualitative MR imaging (p < 0.001, OR 6.9, 95% CI 2.2 to 21.5), onset of epilepsy before the age of five years (p < 0.05, OR 2.9, 95% CI 1.2 to 7.2), and focal seizures with ictal impairment of consciousness and focal ictal EEG as a predominant seizure type (p < 0.05, OR 3.4, 95% CI 1.2 to 9.1) predicted Engel I-II outcome. Hippocampal volume reduction of at least 1 SD from the mean of controls on the side of the seizure onset (p < 0.05, OR 3.1, 95% CI 1.1 to 9.2) also predicted Engel I-II outcome. Conclusions: Outcome at one year postoperatively is highly predictive of long term outcome after temporal lobe epilepsy surgery. Unitemporal MR imaging abnormalities, early onset of epilepsy, and seizure type predominance are factors associated with good postoperative outcome.

Altered physiological brain variation in drug‐resistant epilepsy

“…The most common cause in DRE is MTS, which causes 40%–50% of all DRE cases (Jutila et al., 2002; Lapalme‐remis & Cascino, 2016). Tissue samples of MTS have been shown to present a striking lack of peri‐vascular AQP4 water channels that mediates the glymphatic water clearance (Eid et al., 2005).…”

“…Cohort studies have shown that 30%–40% of epilepsies are drug resistant (Brodie, Barry, Bamagous, Norrie, & Kwan, 2012; Elger & Schmidt, 2008; Laxer et al., 2014; Pitkänen et al., 2016). In anatomical brain scans of patients with drug‐resistant epilepsy (DRE), mesial temporal sclerosis (MTS) has been detected in 40%–50% of the patients (Jutila et al., 2002; Lapalme‐remis & Cascino, 2016), while otherwise the causes of epilepsy fell to other etiologic categories.…”

A New Measure of Visual Location Learning and Memory: Development and Psychometric Properties for the Brown Location Test (BLT)

“…Evidence of the ecological validity of such tests has also been reported (Chaytor & Schmitter-Edgecombe, 2003). Furthermore, criterion validity of verbal memory tests has been obtained in studies of patients with left temporal lobe epilepsy (Sawrie, Martin, Gilliam, Knowlton, Faught, & Kuzinecky, 2001;Siegel et al, 2001;Wilde et al, 2003) and lesions in the left hippocampus (Jutila et al, 2002;Saykin et al, 1992).…”

“…Since these early investigations, a sizeable body of literature has lent considerable support to the association of verbal memory with left hemisphere abnormalities, in particular those involving the hippocampus (Jutila et al, 2002;Sawrie et al, 2001;Saykin et al, 1992;Siegel et al, 2001;White et al, 2002;Wilde et al, 2003). By contrast, larger-scale studies have failed to observe a consistent relationship between performance on clinical tests of visual memory and integrity of the right hippocampus (Giovagnoli, Casazza, & Avanzini, 1995;Gleissner, Helmstaedter, Schramm, & Elger, 2002;Kessels, Dehaan, Kappelle, & Postma, 2001;Lee, Yip, & Jones-Gotman, 2002;Plenger et al, 1996;White et al, 2002;Wilde et al, 2003).…”

82 The Surgical Treatment of Temporal Lobe Epilepsy

“…1 This paper presents results from a national centre for adults in Finland. The strength of this report is that it has long term follow up from a relatively defined population.…”