The effect of preoperative body mass index on outcome after temporal lobe epilepsy surgery

The increasing prevalence of obesity is a significant health care concern. Individuals with obesity, i.e., a body mass index (BMI)>or=30, may have significant comorbid conditions that may increase the risk of general anesthesia and operative procedures. The rationale for the present investigation is to evaluate the importance of obesity on operative outcome in patients with intractable temporal lobe epilepsy undergoing surgical treatment.

This study involved a retrospective analysis of 244 adult patients who underwent epilepsy surgery at Mayo Clinic in Rochester, Minnesota between 1990 and 1996. The mean age of patients at surgery was 35 years (range, 18-68 years). There were 108 male patients (44%). Seventy-three patients (30%) were overweight (BMI 26-29), 56 patients (23%) were obese (BMI 30-39), and nine patients (4%) had extreme obesity (BMI>or=40) at the time of surgery.

The BMI was not predictive of the duration of intensive care unit or hospital stay following surgery, perioperative morbidity, or long-term seizure control following epilepsy surgery. Fifteen deaths occurred in the study period remote from the surgical procedure. The mortality during follow-up was increased for patients with extreme obese (p<0.007).

The perioperative morbidity and seizure outcome following epilepsy surgery was independent of the patient's body weight. However, long-term mortality was significantly increased in the individuals with extreme obesity. The effect of morbid obesity on long-term quality of life after epilepsy surgery may need to be considered in selecting operative candidates.