I will add to tvt’s carefully chosen words. The Chazon Ish’s greatness did not lie in his alleged expertise in neurosurgical techniques. To portray him or other Torah giants as scientific experts is misguided and does not increase our appreciation of them.
Having said that, I spoke with someone who is closely associated with one of the major Jewish publishing companies. I asked him if he’s heard the above story and he replied that it appears in no less than six of his company’s books. He added that he had asked each author to verify the story and each one of them could say only that he “had heard the story from someone else”. No original source, no objective verification and certainly no documentation. Draw your own conclusions.