How much of a person's body could be surgically removed without killing the person?

Sort of inspired by this thread (but something I’ve wondered all along), how much of someone’s body (by weight) could be removed?

Obviously the limbs can go, and there are other unnecessary or redundant organs like one of the kidneys, the spleen, and part of the liver. The outer ears, nose cartilage, and eyes can also go in order to shed some more precious ounces. Then I’d think there’d be a lot of redundant skin, and parts of the intestines could be resected. Finally, I’d assume you could do without some of the torso muscles that insert into the limbs you’re removing.

What else am I forgetting, and what would be the approximate weight loss (by percentage) that would result? Let’s assume that the person isn’t fat, so liposuction would be impractical.

I seem to recall that someone posted on the boards who knew someone who’d had the lower half of his body removed because of some horrible bone disease. ISTR that part of the pelvis was removed, along with everything below. This was called a hemicorporectomy I believe.

I sort of remember that thread also. The person even posted a video of their news story.

One glaring omission from my OP is the reproductive organs.

You could remove 100% of the body without killing the person if you did the whole removal at once.

Need answer fast?

Stephen King wrote a short story about this.

This is pretty much the real life model.

It was a part of Richard K. Morgan’s novel Black Man (published as Thirteen in the US) as well.

In the novel, a person on a Mars-to-Earth ship is not in cryo and is slowly hacking up other passengers in order to eat them so he can survive the months-long trip. At least on of his victims wakes up and notes with horror that she can remember waking up on other occasions and notices that she is missing limbs, just as she hears the saw and other machinery of the autosurgeon start up.

Excellent book (if you’re into science fiction) and thankfully that part of the story only really occupies the first couple of pages.

This thread by angel1366, “Hemicorporectomy Cut in Half to Live”, 10/29/2011.

Take a swab of cells from inside your cheek, and put those into a petri dish to grow. Discard the remainder of the body.

Start with a hemicorporectomy, as stated above. That’s basically everything below the waist. Both arms, gone. Gall bladder and spleen aren’t necessary for survival so those can go. The stomach, colon, rectum and most of the small intestine can go, leaving just enough intestine to prevent short bowel syndrome. One kidney can go, or even both if you want to support the person via dialysis. Same with the pancreas and thyroid. Some people have survived having all but one lobe of both lungs removed, those can go. Up to 90% of the liver can be removed, but it will regenerate.

Ever seen pictures of people mauled by a chimpanzee? Make it so. Say goodbye to the eyes, nose, lips, tongue, teeth, jaw, and even the larynx can be removed I think. However, I’ll leave the ears intact, just so that every shriek of every child, every babe that weeps at your approach, every woman who cries out “DEAR GOD WHAT IS THAT HORRIBLE THING!” will be yours to cherish.

If you want to get fancy, most of the brain can be removed, except for the brain stem itself. That’s probably cheating, though. You can also probably remove most of the spinal column itself, since the person isn’t going to be doing much walking or snapping his fingers. However, the vagus nerve needs to remain intact.

Read Johnny Got His Gun by Dalton Trumbow.

Have you checked German medical literature for the research done by the
doctors of the Third Reich ? They performed all kinds of endurance and survival experiments on prisoners in the detention camps for the Jews. Those medical
experimental results may have been published.

Does replacing with a mechanical version count? If so, the heart and lungs can go. Could also take both kidneys out and connect a dialysis machine.

Hell, technically, you could replace everything but the brain* if you count in life support equipment. And don’t care much about quality of life for the [del]victim[/del] patient.
*Or just part of it as buddha_david thoughtfully notes, with my thanks.

I’m guessing slowly, piece by piece.

Or listen to the musical study notes version.

Recall a cartoon many years ago, in a hospital there’s a giant glass jar with just a brain and a pair of eyes floating inside it. There’s an older couple looking in, and the woman is saying “your father wants to know if we should sell the motorcycle?”

Putting these together you start ending up with something like the Ship of Thesius. At what point do you say its the same person? You could just have just a collection of machines doing their own thing, or as Senegoid says.