Chronic subdural hematomas--causes of morbidity and mortality

Chronic subdural hematoma is a very common condition seen usually in the later stages of life. Treatment, although apparently simple, is associated with some morbidity and mortality with a potential for recurrence. This is especially important as the average life span of humanity increases all over the world.

A retrospective analysis of 647 cases of chronic subdural hematomas treated in NIMHANS was done. The aim of this study was to determine the factors responsible for the morbidity, mortality, and recurrence in patients with chronic subdural hematomas.

The patients were mostly men in the sixth and seventh decade of life and presented with headache, cognitive decline, or focal deficits. CT scan was done in all cases. 94% of the patients underwent evacuation of the hematoma. There was a mortality rate of 5%, and there was a recurrence of 21%. Statistical analysis for factors both for mortality and morbidity were done.

It was seen that statistically significant factors determining mortality were age, GCS at presentation, and associated illnesses like cardiac and renal failure. The statistically significant factors for recurrence are the presence of a thick subdural membrane visualized during surgery and brain, remaining at a depth at the end of evacuation of hematoma. Use of a subdural drain significantly reduced recurrences. The chronicity of the hematoma was not a factor determining mortality or morbidity. Drains were seen to significantly reduce recurrence in younger patients with better GCS and when the subdural membrane is seen at surgery and the brain remains at a depth at the end of hematoma evacuation.