Lindsay Symon: neurosurgery professor and distinguished surgeon whose research into the ischaemic penumbra improved stroke treatment

One evening in the mid-1970s, neurosurgeon Lindsay Symon was walking to dinner at Queen Square in London with his colleague Anthony Strong. They were discussing Symon’s neuroscience experiments, and how an area of tissue death in the brain could have a rim around it where there was no evoked response but what Symon described as the “lethal phenomenon of cell membrane failure” had not yet occurred. Raising blood pressure in the brain could successfully restore life to the area, but the window of opportunity was small—no more than a few hours.

Symon said the area reminded him of a candle flame, where around the bright centre there is a shaded zone known as the penumbra. And so, the concepts of “ischaemic penumbra” and “thresholds of ischaemia” came into being. Symon and his colleagues first published papers on the subject in 1977. This crucial insight into cerebrovascular physiology was essential to recovery after brain surgery and, among other things, led to the modern treatment of stroke with swift administration of clot busting drugs.

In 1990, the Observer magazine, as part …