[Risk factors for seizure recurrence and short term outcome after epilepsy surgery for mesial temporal sclerosis]. / Factores de riesgo para recurrencia de convulsiones y pronóstico a corto plazo en cirugía de epilepsia para esclerosis mesial temporal.

AIM: To establish risk factors for seizure recurrence and short term Engel classification after surgery for mesial temporal sclerosis (MTS). PATIENTS AND METHODS: Nested case-control study in a cohort of patients diagnosed with MTS by magnetic resonance imaging and who had at least two years of postsurgical follow-up; patients with bilateral MTS were excluded. Clinical characteristics, epileptogenic focus in video-electroencefalography (video-EEG) and surgical issues were evaluated regarding to seizure recurrence during the first two postsurgical years and Engel classification in the first and second anniversary after surgery. RESULTS: From October 2001 to June 2008, 144 patients with MTS were evaluated as candidates for epilepsy surgery; until June 2007, 89 patients underwent epilepsy surgery, 51.7% with left MTS. 35.8% of patients experienced seizure recurrence before two post-surgical years; presurgical risk factor associated to this recurrence was bitemporal focus or single temporal focus with contralateral dissemination by video-EEG (odds ratio = 6.32; 95% confidence interval = 1.64-26.41); and post-surgical, seizures that occurred in the first month of surgery (p = 0004). No association with seizure recurrence was found with gender, presurgical tonic-clonic seizures, MTS side and epilepsy duration. 66.3% and 75.8% of patients were Engel I classified in the first and second anniversary after surgery, respectively. 91% of operated patients showed a good outcome after two years of epilepsy surgery. CONCLUSION: Epileptogenic focus location by electrophysiology is a fundamental factor in short term outcome after surgery for MTS.

Factores de riesgo para recurrencia de convulsiones y pronóstico a corto plazo en cirugía de epilepsia para esclerosis mesial temporal / Risk factors for seizure recurrence and short term outcome after epilepsy surgery for mesial temporal sclerosis

Objetivo. Determinar los factores de riesgo para recurrencia de convulsiones y la clasificación posquirúrgica a corto plazo en pacientes operados por esclerosis mesial temporal (EMT). Sujetos y métodos. Estudio de casos y controles anidado en la cohorte de pacientes con EMT diagnosticados por resonancia magnética con dos años de seguimiento posquirúrgico; se excluyeron pacientes con EMT bilateral. Se evaluaron características clínicas prequirúrgicas, foco epileptogénico en videoelectroencefalograma (video-EEG) y variables quirúrgicas con respecto a recurrencia de convulsiones en los primeros dos años tras la intervención y clasificación de Engel en el primer y segundo aniversario de la cirugía. Resultados. Entre octubre de 2001 y junio de 2008 se evaluó a 144 pacientes con EMT candidatos a cirugía de epilepsia; hasta junio de 2007, se había operado a 89 pacientes, un 51,7% con EMT izquierda. El 35,8% de los pacientes presentó recurrencia de convulsiones antes del segundo año tras la intervención; el factor de riesgo prequirúrgico asociado a recurrencia fue foco bitemporal o temporal único con diseminación contralateral por video-EEG (odds ratio = 6,32; intervalo de confianza al 95% = 1,64- 26,41); y el posquirúrgico, la presencia de convulsiones durante el primer mes tras la operación (p = 0,0004); no se encontró asociación con recurrencia para género, convulsiones tonicoclónicas generalizadas prequirúrgicas, lado de la EMT ni tiempo de evolución prequirúrgica de la epilepsia. El 66,3 y el 75,8% de los pacientes estaban en Engel I al primer y segundo año de la cirugía, respectivamente. El 91% de los pacientes intervenidos estaba en buen pronóstico posquirúrgico a los dos años. onclusión. La localización del foco epileptogénico por electrofisiología es un factor determinante en el pronóstico posquirúrgico a corto plazo en la EMT (AU)

Aim. To establish risk factors for seizure recurrence and short term Engel classification after surgery for mesial temporal sclerosis (MTS). Patients and methods. Nested case-control study in a cohort of patients diagnosed with MTS by magnetic resonance imaging and who had at least two years of postsurgical follow-up; patients with bilateral MTS were excluded. Clinical characteristics, epileptogenic focus in video-electroencefalography (video-EEG) and surgical issues were evaluated regarding to seizure recurrence during the first two postsurgical years and Engel classification in the first and second anniversary after surgery. Results. From October 2001 to June 2008, 144 patients with MTS were evaluated as candidates for epilepsy surgery; until June 2007, 89 patients underwent epilepsy surgery, 51.7% with left MTS. 35.8% of patients experienced seizure recurrence before two post-surgical years; presurgical risk factor associated to this recurrence was bitemporal focus or single temporal focus with contralateral dissemination by video-EEG (odds ratio = 6.32; 95% confidence interval = 1.64-26.41); and post-surgical, seizures that occurred in the first month of surgery (p = 0004). No association with seizure recurrence was found with gender, presurgical tonic-clonic seizures, MTS side and epilepsy duration. 66.3% and 75.8% of patients were Engel I classified in the first and second anniversary after surgery, respectively. 91% of operated patients showed a good outcome after two years of epilepsy surgery. Conclusion. Epileptogenic focus location by electrophysiology is a fundamental factor in short term outcome after surgery for MTS (AU)