Paediatric epilepsy surgery in the posterior cortex: a study of 62 cases

Epilepsies originating from the posterior cortex, namely the parieto-occipital lobes and the occipital border of the temporal lobe, account for the minority of focal epilepsies (Boesebeck et al., 2002), therefore, epilepsy surgery in the posterior cortex has been less extensively examined in the literature, relative to that for temporal or frontal lobe epilepsies.

Most studies emphasize the difficulty in delineating the precise localisation of a posterior epileptogenic zone (EZ: the site of origin and of primary propagation of ictal discharges; Bancaud et al., 1970; Kahane et al., 2006) because of rather non-specific clinical seizure patterns (Bancaud, 1969; Williamson et al., 1992; Boesebeck et al., 2002; Bartolomei et al., 2011). Ictal semiology in posterior cortex epilepsy (PCE) will vary according to the discharge pathway and can falsely localise to the anterior cortical regions. This difficulty is even more relevant in paediatric epilepsy, as EEG patterns are frequently generalised and the subjective and objective chronology of ictal semiology is difficult to obtain.

Paediatric series of PCE surgery are rare (Sinclair et al., 2005; Mohamed et al., 2011; Ibrahim et al., 2012); children are frequently included in surgical series of adult patients undergoing either occipital lobe epilepsy (OLE) surgery (Salanova et al., 1992; Williamson et al., 1992; Caicoya et al., 2007; Binder et al., 2008; Tandon et al., 2009), parietal lobe epilepsy (PLE) surgery (Binder et al., 2009) or PCE surgery (Dalmagro et al., 2005; Yu et al., 2009; Jehi et al., 2009). Therefore, the aim of this study was to characterise the anatomo-electro-clinical features and to describe the surgical outcome of an exclusively paediatric patient population, surgically treated for drug-resistant PCE.