Fat and neurosurgery: does obesity affect outcome after intracranial surgery?

OBJECTIVE: Obesity has been linked to increased morbidity and mortality after some surgical procedures. The purpose of this study was to determine whether obesity affects outcome after general neurosurgery and subarachnoid hemorrhage (SAH). METHODS: Three data sets were analyzed, including a retrospective review of 404 patients undergoing cranial and spinal neurosurgical procedures, a prospective collection of 100 patients with aneurysmal SAH, and data from 3567 patients with aneurysmal SAH who were entered into randomized clinical trials of tirilazad. For each data set, outcome was assessed by mortality, postoperative morbidity, and Glasgow Outcome Scale score. Prognostic factors, including body weight and body mass index, were tested for their effect on these outcomes using multivariable logistic regression. RESULTS: For patients undergoing general cranial and spinal neurosurgery, independent predictors of morbidity and mortality were age, American Society of Anesthesia class, disseminated malignancy, emergency surgery, and increased duration of surgery. For patients with SAH, score on the Glasgow Outcome Scale was associated with age and admission Glasgow Coma Scale score. In the tirilazad data set, multiple factors were associated with score on the Glasgow Outcome Scale, but, as with the other 2 data sets, body weight had no relationship to outcome. CONCLUSION: Obesity may have less effect on the outcome of patients with mainly cranial neurosurgical disease and aneurysmal SAH than it does on patients undergoing other types of surgery.

Prognostic factors for outcome in patients with aneurysmal subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: The purpose of this study was to describe prognostic factors for outcome in a large series of patients undergoing neurosurgical clipping of aneurysms after subarachnoid hemorrhage (SAH). METHODS: Data were analyzed from 3567 patients with aneurysmal SAH enrolled in 4 randomized clinical trials between 1991 and 1997. The primary outcome measure was the Glasgow outcome scale 3 months after SAH. Multivariable logistic regression with backwards selection and Cox proportional hazards regression models were derived to define independent predictors of unfavorable outcome. RESULTS: In multivariable analysis, unfavorable outcome was associated with increasing age, worsening neurological grade, ruptured posterior circulation aneurysm, larger aneurysm size, more SAH on admission computed tomography, intracerebral hematoma or intraventricular hemorrhage, elevated systolic blood pressure on admission, and previous diagnosis of hypertension, myocardial infarction, liver disease, or SAH. Variables present during hospitalization associated with poor outcome were temperature >38 degrees C 8 days after SAH, use of anticonvulsants, symptomatic vasospasm, and cerebral infarction. Use of prophylactic or therapeutic hypervolemia or prophylactic-induced hypertension were associated with a lower risk of unfavorable outcome. Time from admission to surgery was significant in some models. Factors that contributed most to variation in outcome, in descending order of importance, were cerebral infarction, neurological grade, age, temperature on day 8, intraventricular hemorrhage, vasospasm, SAH, intracerebral hematoma, and history of hypertension. CONCLUSIONS: Although most prognostic factors for outcome after SAH are present on admission and are not modifiable, a substantial contribution to outcome is made by factors developing after admission and which may be more easily influenced by treatment.