Is surgery necessary when you have blood clots in your brain?

Sometimes: Many times embolic strokes are treated with blood thinner which can open up blocked arteries. For most patients surgery is rarely done.

Depends: In the brain, not so common. Stroke not common tumor with bleed yes. Aneurysms or avm yes pressing on the brain, common.( subdural or epidural).

Based on situation: If an aneurysm or ateriovenous malformation has caused problem, surgical repair may be life saving. If a subdural or epidural hemorrhage, best to decompress unless very small and stable. If intracranial bleeding, may be far safer to be conservative, and not operate. But all situations are different and management decisions should vary.