Replantation: How Severed Body Parts Are Reattached

The clock

Tissue without a blood supply starts to die, and warmth speeds that up. A man whose forearm was severed reached a trauma centre 45 minutes later, and the surgical decision had to be made in minutes. In another case, a hand taken off by a block-cutting machine had blood crossing it again about four hours after the injury, inside the six-hour window.

Shown in MC-010: Replanting an arm: the clock, and the harder question · also MC-038

How a severed part should travel

The part is wrapped in gauze moistened with saline, sealed in a bag, and the bag is put on ice. Tissue should never sit against the ice itself, which freezes and destroys it. Vessels bleeding in the stump are not clamped, because a clamp crushes a vessel that is about to be sewn to another one; pressure and elevation are used instead.

At the hospital, time is saved by working in parallel. While one team resuscitated the patient, another operated on the severed hand on a side table, shortening its bones and tagging every vessel and nerve so that nothing had to be searched for later. The bone was shortened on the hand rather than the stump, so that if the replantation failed he would keep the length he had.

Shown in MC-038: They operated on the hand before they operated on him

Getting blood in is the easy half

Arteries are thick-walled and hold their shape. Veins are thin, collapse easily, and in an avulsion they are torn along their length, so after a technically successful replantation blood can arrive faster than it can leave. The aim is at least one artery in and two veins out.

A scalp torn off in a laundry machine was sewn back within four hours and then began to drown in blood that had no way out. Leeches were the answer: the volume they drink is trivial, but their bite keeps oozing for hours, draining the tissue until the body grows veins of its own. It took about ten litres of transfused blood over nine days.

Shown in MC-034: The bleeding was the treatment · also MC-038

Whether to reattach at all

Replantation is not automatic. Other injuries or illness that make a long operation dangerous, damage at several levels rather than one, and a crush rather than a clean cut all count against it. When a man who had removed his own forearm arrived with untreated depression, the surgical decision was straightforward; the harder question was whether reattaching it was right, and his six-year result depended as much on psychiatric care starting on day one as on the microsurgery.

Shown in MC-010: Replanting an arm: the clock, and the harder question · also MC-038

What it gives back

Survival of the replanted part is the easiest thing to measure and the least interesting. The forearm replanted in MC-010 had full function six years later and he was back at work. The scalp in MC-034 grew hair over about 85% of its area by three years. The hand in MC-038 had a flicker of finger movement at three weeks, with a year of physiotherapy and probably further operations still to come.

Shown in MC-038: They operated on the hand before they operated on him · also MC-010 and MC-034

The cases

1. 4 hto blood flowing againMC-038ReconstructionThey operated on the hand before they operated on himA machine took his hand off through the forearm. One team worked on the hand on a side table while the other prepared him, and blood was crossing it again four hours later.
2. 6 hof viabilityMC-010ReconstructionReplanting an arm: the clock, and the harder questionSix hours of viability, and a decision about whether to reattach a limb the patient removed himself.
3. 10 daysof leeches, and ten litres of bloodMC-034ReconstructionThe bleeding was the treatmentHer scalp came off in one piece and was sewn back on within four hours. Getting blood in was the easy half; the flap was drowning in blood that could not leave.