The Operation That Created ‘Patient H.M.’

Author Luke Dittrich retells the story of the surgery his grandfather performed on Henry Molaison, which resulted in an unintended, life-changing side effect.

The following is an excerpt from Patient H.M. by Luke Dittrich.

There was no focus.

This meant, of course, that there was no target, no specific place in Henry’s medial temporal lobes to attack, not even a hint of which hemisphere Henry’s seizures originated in.

If another neurosurgeon had been in my grandfather’s shoes that day, things might have turned out differently. Wilder Penfield, for example, would have conceded defeat. Penfield had clear rules of engagement in the operating room: If he couldn’t determine a focus either visually or through EEG, he wouldn’t make any lesions. In fact, even if the EEG hinted at the presence of an epileptic focus, but visual inspection of the brain revealed no abnormalities, Penfield made it a point to do nothing rather than make an excision that might do more harm than good. “The neurosurgeon,” Penfield once wrote, “must balance the chance of freeing his patients from seizures against the risks and functional losses that may be associated with ablation.” In that balancing act, Penfield always erred on the side of caution, and in Henry’s case, with no target, he would have decided not to proceed with the operation. He would have stitched Henry up, kept him a few days for observation, and sent him home with an apology and a refill of his prescriptions. He would have told him that there didn’t appear to be anything he could do for him surgically, at least not then, and not with the information they had.

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My grandfather was not Wilder Penfield.

Standing there in his operating room, looking down at the wet expanse of Henry’s skull, glimpsing his exposed brain through the two trephine holes, my grandfather could have admitted defeat, could have ended the operation. This would have been the safest move. There was no chance Henry would be improved by following that course of inaction, but there was also no chance he would be hurt by it.

Alternately, he could have chosen to take one, and only one, of the paths ahead. He could have operated on Henry’s left hemisphere, or Henry’s right hemisphere, then withdrawn, patched him up, and seen what happened. He had no target, no specific evidence of an epileptic focus in either hemisphere, but maybe he would get lucky. This would be the surgical equivalent of a coin toss: If one hemisphere of Henry’s medial temporal lobes was the hidden source of his epilepsy, then that approach would have a 50 percent chance of eliminating it. It would be much riskier, of course, than doing nothing, but that might be viewed as a reasonable risk considering the severity of Henry’s condition. Also, by leaving the structures in one hemisphere intact, he would minimize the chance of destroying whatever the unknown functions of those structures were.

My grandfather chose a third option. He picked up his suction catheter, inserted it carefully into one of the trephine holes, and proceeded to suction out that hemisphere of Henry’s medial temporal lobes. His amygdala, his uncus, his entorhinal cortex. His hippocampus. A good portion of all of those mysterious structures disappeared into the vacuum. Then he pulled the tool out of the first hole, cleaned it off, and inserted it into the second. Lacking a specific target in a specific hemisphere of Henry’s medial temporal lobes, my grandfather had decided to destroy both.

Patient H.M.: A Story of Memory, Madness, and Family


At that moment, the riskiest possible option for his patient was the one with the most potential rewards for him. After years of straddling the line between medical practice and medical research in the back wards of asylums, of attempting to both cure insanity and gain an understanding of various brain structures, he was about to perform one of his medial temporal lobotomies on a man who was not mentally ill at all, whose only dysfunction was epilepsy. In the language of scientific research, Henry was a “normal,” or at least much closer to being a normal than anyone who’d  previously received one of my grandfather’s limbic lobe operations. For four years, my grandfather had been conducting “a study of the limbic lobe in man,” and so far he had only “small bits of passing data” to show for it. That afternoon, however, my grandfather’s study was expanding to include a whole different class of research subject.

Imagine my grandfather peering into that second trephine hole, guiding his suction catheter deeper and deeper, his headlamp illuminating the intricate corrugations of the structures he was in the process of destroying. It’s impossible to say exactly what thoughts drove him at that moment, what stew of motives. He had reason to believe his operation might help alleviate Henry’s epilepsy. He also had reason to believe his operation might provide new insight into the functions of some of the most mysterious structures in the human brain. It’s quite possible that he wasn’t thinking much at all, at least not consciously. Years later, during a rare moment of introspection, he described himself as follows: “I prefer action to thought, which is why I am a surgeon. I like to see results.”

He pressed the trigger on the suction catheter, and the remaining hemisphere of Henry’s medial temporal lobes vanished into the vacuum.

He finished the operation.

He removed the tools.

He replaced the bone and stitched the flesh.

Six weeks later, he sent off a print version of his Harvey Cushing Society presentation to the Journal of Neurosurgery  for publication. The paper contained one major addition to the remarks he’d made onstage back in April. His limbic lobe operations, he now wrote, had “resulted in no marked physiologic or behavioral changes, with the one exception of a very grave, recent memory  loss, so severe as to prevent the patient from remembering the locations of the rooms in which he lives, the names of his close associates, or even the way to toilet or urinal.

The italics were his, and that italicized clause transformed a forgettable, modest paper into one that will continue to be referenced for as long as we remain interested in how we hold on to the past. It became a cornerstone of the skyscraper that is modern memory science.

It was the birth announcement of Patient H.M. It was also the obituary of Henry Molaison.

From the book, Patient H.M. by Luke Dittrich. Copyright © 2016 by Luke Dittrich. Reprinted by arrangement with Random House, an imprint of The Random House Publishing Group, a division of Penguin Random House, Inc. All rights reserved.

Meet the Writer

About Luke Dittrich

Luke Dittrich is a journalist and is the author of Patient H.M.: A Story of Memory, Madness, and Family Secrets. He’s based in Boston, Massachusetts.

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