Primary or secondary decompressive craniectomy: different indication and outcome.

BACKGROUND Intracranial hypertension can cause secondary damage after a traumatic brain injury. Aggressive medical management might not be sufficient to alleviate the increasing intracranial pressure (ICP), and decompressive craniectomy (DC) can be considered. Decompressive craniectomy can be divided into categories, according to the timing and rationale for performing the procedure: primary (done at the time of mass lesion evacuation) and secondary craniectomy (done to treat refractory ICP). Most studies analyze primary and secondary DC together. Our hypothesis is that these two groups are distinct and the aim of this retrospective study is to evaluate the differences in order to better predict outcome after DC. METHODS Seventy patients had DC over a period of four years at our center. They were divided into two groups based on the timing of the DC. Primary DC (44 patients) was done within 24 hours of the injury for mass lesion evacuation. Secondary DC (26 patients) was done after 24 hours and purely for the treatment of refractory ICP. Pre-op characteristics and post-op outcomes were compared between the two groups. RESULTS There was a significant difference in the mechanism of injury, the pupil abnormalities and Marshall grade between primary and secondary DC. There was also a significant difference in outcome with primary DC showing 45.5% good outcome and 40.9% mortality and secondary DC showing 73.1% good outcome and 15.4% mortality. CONCLUSIONS Primary and secondary DC have different indications and patients characteristics. Outcome prediction following DC should be adjusted according to the surgical indication.