Introduction: The presence of a structural lesion in the preoperative magnetic resonance imaging (MRI) of drug-resistant epilepsy patients has been usually associated with a favourable surgical outcome. We present our experience in our Epilepsy Surgery Unit.
Patients and methods: Clinical records from 265 patients, operated on from 1990-2010 in our institution, were reviewed. Patients were classified, according to MRI findings, into three groups: surgical lesion (SL), tumors or vascular malformations requiring surgery 'per se'; orientative lesion (OL), dysplasia, atrophy or mesial temporal sclerosis; and (NL) group, with normal MRI. Seizure outcomes were analysed in relation to this classification.
Results: Period 1990-2000, 151 patients: 87% of SL, 65% of OL and 57% of NL patients were in Engel class I or II at the two-year follow-up. Among temporal lobe epilepsy cases (TLE), 87% of SL, 67% of OL and 56% of NL patients achieved seizure control. Differences were statistically significative. Period 2001-2010, 114 patients: 100% of SL, 90% of OL, and 81% of NL patients were in Engel's class I or II. Both TLE and extratemporal (ETLE) SL patients obtained a 100% seizure control. Among the OL patients, 95% with TLE and 43% of ETLE achieved seizure control. In the NL group, the percentages were 88% in TLE, and 50% in ETLE.
Conclusions: In our series, SL was a predictor of a favorable outcome. In TLE patients, good results were achieved despite normal MRI. Patients with ETLE and NL did not have a worse outcome than those with OL. A classification in SL, OL and NL seems more helpful for predicting the surgical outcome than the traditional classification lesion versus non-lesion MRI. Radiological findings must be carefully evaluated in the context of a complete epilepsy surgery evaluation.
Title: Clasificacion de las lesiones estructurales en resonancia magnetica. Implicaciones quirurgicas en pacientes con epilepsia farmacorresistente.
Introduccion. En la seleccion quirurgica del paciente con epilepsia farmacorresistente, el papel de la resonancia magnetica (RM) no se ha cuantificado hasta el momento. Presentamos la experiencia en nuestra Unidad de Cirugia de la Epilepsia. Pacientes y metodos. Se estudiaron retrospectivamente los pacientes intervenidos por epilepsia farmacorresistente. Distinguimos dos periodos: 1990-2000 (RM de 0,5 T) y 2001-2008 (RM de 1,5 T). La RM preoperatoria se clasifico en tres grupos: RM con lesion quirurgica (LQ), RM orientativa (LO) y RM normal (NL). Tambien se efectuo una clasificacion anatomopatologica similar. Se correlacionaron las distintas clasificaciones y los resultados quirurgicos. Resultados. Periodo 1990-2000: 151 pacientes. El 70% quedo en las clases de Engel I o II. Segun la RM, los resultados fueron: LQ, 87%; LO, 65%; y NL, 57%. Las diferencias fueron estadisticamente significativas. Periodo 2001-2008: 114 pacientes. El 89% quedo en las clases de Engel I o II. Segun la RM: LQ, 100%; LO, 90%; y NL, 81%. Las diferencias fueron estadisticamente significativas. Los pacientes con epilepsia del lobulo temporal y extratemporal con LQ tuvieron un 100% de control; con LO, el 95% con epilepsia del lobulo temporal y el 43% con estado epileptico; en aquellos pacientes sin lesion (NL), el 88% con epilepsia del lobulo temporal se controlo frente al 50% con estado epileptico. Conclusiones. La RM es una herramienta eficaz en la seleccion de candidatos quirurgicos en la epilepsia. La LQ asocia muy buen pronostico. En la epilepsia del lobulo temporal se pueden obtener muy buenos resultados (80-90% de control) a pesar de una RM normal. En el estado epileptico, las LO pueden tener peor resultado que la NL en la RM.