Authors :
C.E. Polkey, MD FRCS, Neurosurgery, King[ssquote]s College Hospital, London, United Kingdom; C.D. Binnie, MD FRCP, Clinical Neurophysiology, King[ssquote]s College Hospital, London, United Kingdom
RATIONALE: This is a retrospective study of patients undergoing resective surgery with a pathological diagnosis in the resected specimen of either cortical dysplasia(CD), including multilobar lesions and hemimegalencephaly, or DNET lesion. These patients were treated in the Epilepsy Surgery programme at the Maudsley Hospital and since 1995 at King[scquote]s College Hospital.
METHODS: There were 21 patients with a diagnosis of DNET and 42 patients with CD. The location of the lesions and the age at operation is shown in the tables below. All patients went through the presurgical assessment programme with the investigations which were available at the time. Thus from 1978 most patients had CT and since 1990 MRI but only recently with FLAIR sequences. Where possible neuropsychological assessments and developmental assessments were obtained. Neurophysiological investigation was very variable and dependent upon the available techniques and complexity of the case varying from non-invasive interictal EEG only in some cases, to the recent use of orthogonal depth electrodes in two patients with frontal lobe seizures and negative MRI examinations. ICED[scquote]s ( Interictal continuous epileptifom discharges) at EcoG or chronic recording were seen more commonly in CD, occurring in 25/29 patients with CD (86%), 6/22 patients with DNET (27%) and 2/33 patients with tumours (6%).
| Table 1 - Location of lesions |
| Temporal | Frontal | Other | Hemispheric | |
| CD | 8 | 15 | 10 | 7 | |
| DNET | 18 | 2 | 1 | 0 | |
| CD has an obvious predilection for extra-temporal sites compared with DNET( 80% cf 14%) |
| Table 2 - Age at surgery |
| 0 [ndash] 5 | 6 [ndash] 10 | 11 [ndash] 15 | 16 [ndash] 20 | 20 + |
| CD | 7 | 8 | 10 | 9 | 9 |
| DNET | 3 | 3 | 2 | 6 | 7 |
| CD presents to surgery at an earlier age than DNET ( 58% age 15 or less cf 38%) |
RESULTS: Follow-up was available for the CD patients for 2 [ndash] 161 months (mean 56.7 = 3.9 yrs) and for the DNET group for 8 [ndash] 186 months (mean 44.5 = 3.7 yrs) The outcome in relation to the Engel groups was very similar. In CD 30% of patients were 1A, 12% 1, 30% 2 [ndash] 3A with 28% unaffected. In DNET the figures were 1A 38%, 1 14%, 2 [ndash] 3A 16% and 32% unaffected.
Table [ndash] Seizure relief in relation to completeness of removal[table]Completeness of removal was gauged by operative findings, pathological reports and postoperative imaging.
CONCLUSIONS: In both CD and DNET lesions permanent freedom from seizures is obtained in 30-40% of patients after appropriate resective surgery with an improvement in seizure control in about 70% of patients so treated.
Support: nil