Likening neurosurgery to high-stakes poker. That's what "knife-edge" surgery for refractory epilepsy is. Incredible stories, but sometimes tragic side effects:

Mr Chandler said: "We went for broke in terms of what we were taking out because it was important to make sure that we got absolutely every last area that might be causing the seizures."

The surgery was a success and Sarah has been free of seizures for four months. However, because of the extent of tissue that had to be removed, she has lost some peripheral vision and can no longer see things clearly to her right.

Mr Chandler said: "It's never nice to have to talk to somebody about the deficit you might inflict, and even more difficult to see that a patient has got a deficit.

"Every neurosurgeon has had to face that."

("'Knife edge' surgery for epilepsy", BBC, Jul.27)