Abstracts

Anticonvulsant prophylaxis (AP) is recommended in various neurosurgical diseases, but no definite agreement is obtained regarding indication and choice of an antiepileptic drug (AED), doses and treatment duration.
A multicentric retrospective non-randomized survey was conducted in order 1) to assess current practice regarding anticonvulsant prophylaxis in most French neurosurgical centers ; 2) to document the incidence of seizures in a given disease ; 3) to provide further recommendations for seizure prevention and treatment in neurosurgical practice. The survey enrolled 67 academic, general hospitals and private centers of neurosurgery. One hundred consecutive patients admitted in each participating center from March 1, 1998 for the treatment of intracranial supratentorial disease were entered in the study. The SAS software was used for descriptive statistics and a stepwise logistic regression model assessed the weight of different risk factors for seizures.
5852 patients were included in the main descriptive analysis. Mean age was 50.8 yrs. 63.1% of them had a surgical procedure, 45.5 % had a craniotomy. Main diseases were tumoral (35.4%), traumatic (34.7%) and vascular (20.5%). Mean observation period was 301 days. 57.1% of patients received an AED at any moment of the observation period (main AED were valproate, carbamazepine and phenobarbital). Adverse effects were observed in 3.7% of patients. Among 5037 patients evaluable for epileptic seizures, a seizure occurred in 21.6% of patients at any time of the observation period, while 78.4% had no seizure. AED was prescribed in prevention in 44.4% of all cases, and after a first seizure in 9%. Success rates (percentage of patients receiving prophylactic AED and having no seizure) were: 90.6% for traumatic, 81.6% for vascular, 70.4% for tumoral and 66.6% for infectious lesion. Failure rates (percentage of patients receiving prophylactic AED and having at least a seizure) were: 9.4%, 18.4%, 29.6%, and 33.3% respectively. Factors positively correlated with seizure occurrence were: tumoral lesion, long-term antiepileptic treatment, craniotomy, cortical / subcortical lesion location. Factors negatively correlated with seizure occurrence were : traumatic lesion, hydrocephalus, age [lt] 16 or [gt] 60 yrs. Odds ratios were estimated to 3 for long-term AE treatment and cortico-subcortical lesion location, 2 for chronic alcoholism, 1.8 for craniotomy and 1.4 for tumoral lesions.
The present study demonstrated that relative risks for seizure occurrence are different in various neurosurgical diseases. Therapeutic management should take into account that patients having 1) cortico-subcortical lesion, 2) chronic alcoholism, 3) craniotomy, and 4) cerebral tumor, are more at risk of seizure.
[Supported by: Pfizer Global Pharmaceutics France]