PREOPERATIVE MRI PREDICTS OUTCOME OF TEMPORAL LOBECTOMY - AN ACTUARIAL ANALYSIS

We used actuarial methods to study outcome after temporal lobectomy in 135 consecutive patients classified into subgroups according to preop erative MRI findings. Sixty months after surgery, 69% of patients with foreign tissue lesions, 50% with hippocampal sclerosis, and 21% with normal MRIs had no postoperative seizures. An eventual seizure-free st ate of 2 years or more, whether the patient was seizure-free since sur gery or not, was achieved by 80% of patients with foreign tissue lesio ns, 62% of those with hippocampal sclerosis, and 36% of those with nor mal MRIs. Outcome was worse in those with normal MRIs than in the othe r two groups. Early postoperative seizures with later remission (the ' 'running down'' phenomenon) occurred in all groups. Late seizure recur rence was present only in the hippocampal sclerosis group. These data show that preoperative MRI is a useful predictor of outcome and that a ctuarial analysis provides insight into different longitudinal pattern s of outcome in MRI subgroups. This information can now be used in pre operative counseling.