The fallacy of the lacune hypothesis.

We review the definition, pathogenesis, natural history, and prognosis and describe the first experimental model of lacunes. Defined pathologically or radiologically, lacunes are small cerebral infarcts which become cystic and are caused by occlusion of small arteries. The clinical definition of lacune is confused. The word "lacune" means a small stroke. While the immediate mortality rate from a small stroke is low, many patients are unable to return to work and the long-term prognosis is guarded. Photochemical damage to the carotid artery of rats produces microemboli to the brain, resulting in cavitary lesions resembling lacunes in humans. The "lacune hypothesis" is a fallacy because small cerebral infarcts are not caused solely by a combination of hypertension and small vessel disease, and the various "lacunar syndromes" are simply small strokes which should be investigated as such.