Which part of the body dies first

How do you survive for hours with a ripped arm off?

Tibor A. is laughing again. The 37-year-old Hungarian is lying at the Vienna University Clinic for Trauma Surgery, where the doctors sewn his right forearm back on last Saturday, which had been torn off in a work accident in Purbach, Burgenland. The media reported on a "successful operation" and gave the impression that the sewn arm would regain its functionality after a few weeks or months. But there can be no question of that. In this case, successful surgery only means that the forearm is supplied with blood again.

Neither the anatomy of the muscles and tendons nor that of the nerves has been reconstructed. Because in this first phase of treatment, only the blood flow to the sewn-on part of the body is essential. The entire angled arm is held in place by external metal rods for about six weeks. Only after the wounds have healed, the doctors can decide which follow-up operations are sensible and feasible. Even after the muscles, tendons and nerves have been reconstructed, the elbow joint is likely to have limited mobility and the fingers to remain functionless. The next two weeks will show whether the forearm has actually been saved.

Because the blood and oxygen supply is interrupted for hours, tissue cells die in the severed body part and form toxic substances that can lead to kidney failure. Due to the massive contamination of the wounds, there is also the risk of life-threatening sepsis. Although the treating physicians try to keep the risk of infection low by means of antibiotic infusions, germs can spread more easily in previously damaged tissue. In the event of sepsis, the sewn forearm would have to be amputated again immediately to save the patient's life. There was also a risk of thrombosis and rejection, but by the middle of this week all of these hurdles seemed to have been overcome for the time being.

Survival program

The Hungarian worker, who has been working for a recycling company in Purbach for years, was alone on the premises at the time of the accident. He was busy chopping up and sorting rubble with the help of a vibrating screen. For this purpose, concrete or brick chunks are conveyed via a conveyor belt into a crushing roller and then onto the vibrating screen. At around 1.30 p.m. a large stone blocked the machine, which is why Tibor A. tried to release the blockage with the help of an iron bar. When the belt suddenly started moving again, a conveyor slat grabbed A.'s right arm and pulled him into the machine, the forearm tearing off at the elbow.

The worker was able to turn off the machine, ran to his car, then back to the machine. He found the severed forearm in the dusty rubble, put it in his sweater, and deposited it in the trunk. How he managed to steer his car 20 kilometers to the nearest hospital in Eisenstadt and into the underground car park with his left arm alone is just as puzzling as his calm appearance at reception: He put his forearm, covered in dust and blood, on the desk and asked to sew it back on for him.

For laypeople it is incomprehensible how a person with such a serious, potentially life-threatening injury can still drive a car and think clearly; that instead of screaming in pain or fainting, he'll stay cool and do just the right thing to save his arm and himself. This is not due to the shock, as has been reported many times, but rather a survival program that nature has in place in the event of massive, life-threatening injuries. After severe physical injuries, many patients often report that they hardly felt any pain.

Self-help mechanism
The reason for this is the immediate massive release of stress hormones and psychotropic substances in the brain, which on the one hand increase the pulse rate and on the other hand reduce the sensation of pain: a self-help mechanism that guarantees that the patient is still able to react. In this situation, the organism reduces the blood flow to peripheral areas of the body in favor of the heart and brain. "With this so-called centralization, the body primarily supplies vital organs," explains Michael Blauth, Director of the Innsbruck University Clinic for Trauma Surgery.

The stress response even stops the bleeding
because the peripheral vessels contract and close by themselves at the injury site. This happens when the innermost layer of the artery, the intima, curls up at the cut or tear point and thus stops the flow of blood. In addition, a blood clot forms locally that prevents bleeding. The wound then only bleeds slightly from the injured veins that do not have such a closing mechanism. "It is often amazing how little such amputation injuries bleed," says Blauth. Without this self-protection, the patient would bleed to death. But there was never such a danger with Tibor A.

The doctors in Eisenstadt packed the severed forearm properly in a sterile nylon sack and placed it in a second nylon sack filled with water and ice cubes for cooling. It is important that the severed body part does not come into direct contact with the ice, as this could lead to tissue damage from the cold. The amputate, packed in ice, was also stowed in a cool box for transport. Due to the low temperature, the metabolic processes in the cells slow down and the breakdown process is stopped. It is known from transplant medicine that the ideal temperature for the preservation of donor organs or amputates is around four degrees Celsius.

In the Eisenstadt hospital, the patient was put into artificial deep sleep, intubated, given isotonic infusions via a central venous catheter, put into artificial deep sleep and the wound on the upper arm was bandaged with a transparent, sterile film. At the same time, the hospital alerted the emergency doctor's helicopter and the accident surgery department at Vienna General Hospital. The team there was currently working on a major operation, but was able to finish the ongoing operation on time due to the notification. At first it was uncertain whether the helicopter would even be able to take off because of the bad weather and squalls. In the event of a necessary transfer in an ambulance, the transport time would have quadrupled from 15 minutes to one hour. But then the rescue in the small flying intensive care unit worked.

When the transport arrived at Vienna General Hospital just before 5 p.m., a nine-person surgical team was already ready for the major operation: a trauma surgeon, a plastic surgeon, two assistants, an anesthetist, two X-ray assistants and two nurses. First, the patient was brought to the emergency room, which was set up for all eventualities.

"We got a circulatory and respiratory stable patient," reports the senior physician, Monika Luxl, who was significantly involved in the operation. That means that the supply of the man in Eisenstadt and during the transport had been optimal. To keep the risk of infection low, the amputate and upper arm stump were initially only inspected through the plastic cover, exposed and cleaned, but only in the operating room. The extent of the injury was shown: It was a typical avulsion injury without smooth wound edges, which is less favorable for the transplantation. In addition, there was stretch damage to the soft tissues, which reached up to the shoulder in the upper arm and close to the wrist in the forearm. In addition to the visible damage, there was also invisible damage caused by ruptured blood vessels and nerve cords. Blood vessels are like elastic tubes which, when stretched extremely, often tear in completely different places. As a result, for example, the two main supply lines, arteria radialis and arteria ulnaris, which run in the forearm, do not tear off at the elbow joint like the entire forearm, but about ten and 20 centimeters below, respectively.

Even further away from the elbow joint were the tear-off points of the three large nerve tracts running in the arm, which behave like rubber bands when stretched. The median nerve tore in the middle of the forearm, the ulnar nerve in the upper shoulder area just after it emerged from the spine. This complicates the reconstruction, which is only planned for a later reoperation.

To save time, two surgical teams were formed: team one prepared the torn forearm for replantation, team two the upper arm. The surgeons searched for the ends of the vessels and nerves on both the amputate and the upper arm stump and exposed them. In order to be able to join and stabilize the two body parts, the surgeons mounted several iron rods in the bones of the forearm and the upper arm at right angles, which, screwed with cross braces, form an external stabilization framework, the upper and forearm at a 90 degree - Holds the angle together in the elbow.
Once the bone structure of the elbow joint was restored, the surgeons could begin reconstructing the blood vessels. The destroyed sections were replaced by pieces of vein from the legs. Only then could the doctors sew muscles and skin together. A reconstruction of the essential nerve tracts is not planned for the time being.

It should not be attempted until a later operation, when the wounds have healed, in three weeks at the earliest. And even once the nerve tract is reconstructed, it can take years before it gives a feeling. Because the path only tells the nerve the direction in which it should grow.

A nerve grows about a tenth of a millimeter per day. It is easy to calculate how long it will take to re-establish the neural connection from the shoulder to the fingertip, a distance of 800 millimeters. And even then it is questionable whether the muscles of the hand are not already so atrophied that they can no longer fulfill any function.

Seen in this light, the idea that the arm will at some point be fully functional again is a pious wish. It may be necessary to amputate the functionless hand and replace it with a so-called myoelectric prosthesis, which can transmit impulses from individual muscles to the fingers - a topic that the plastic surgeon Oskar Aszmann, a member of the surgical team, is dealing with. busy for years.

For the time being, the doctors are satisfied that the transplant has been accepted by the body and is well supplied with blood. “The patient does not feel the replanted forearm. If he closes his eyes, he doesn't know whether it's his arm or not, ”says trauma surgeon Luxl. "But better an arm with limited function than no arm at all."