QuestionWhich appendages can be reattached?
Hopes&Fears answers questions, with the help of people who know what they're talking about. Today, we get to the gory as we examine the science of reattaching lost body parts.
Partially inspired by the first successful penis transplant which happened this past week in South Africa, Hopes&Fears wondered about all of our treasured appendages. Which ones can be reattached? What complications come from reattaching certain appendages? And how long can you wait after losing a limb before reattaching it successfully?
To answer this question, we talked to Dr. O. Allen Guinn III, M.D., F.A.C.S., an accredited plastic surgeon and published author based out of Lee’s Summit, Missouri. Dr. Guinn gave us the full rundown on the do’s and don'ts of losing a body part.
Dr. O. Allen Guinn III
M.D., F.A.C.S., an accredited
plastic surgeon and published author
FIRST, THE DEFINITION OF AN APPENDAGE: It is anything that protrudes from the body's core. It would include arms and legs, and the smaller components like fingers and toes. It would also include ears, the nose, genitalia in males and possibly even the nipple in a female.
In theory, any appendage that is amputated (cut off) can be reattached, with the degree of success being dependent on several factors.
THE METHOD BY WHICH THE APPENDAGE WAS AMPUTATED
A) Sliced off with a sharp object, with minimal tissue injury. This provides the best chance for a successful reattachment.
B) Cut off with a saw, with the loss of a "kerf" of tissue (the material removed by the width of the saw blade). The reattachment is complicated by the missing tissue, which can include bone, or cartilage. The reattached piece may not have the same length or appearance as the original.
Different saws leave different width kerfs, such as the difference between a bandsaw and a chain saw. The greater the kerf, the more the deficit to be dealt with.
C) Pulled off, with the appendage forcibly torn from its attachment. In these cases, the appendage, say a finger, may not be able to be reattached due to the vessels or nerves being avulsed at different lengths. Occasionally an amputated finger will have several centimeters of nerve or blood vessel hanging from the amputated end. Finding the proximal, or "upstream" end may be impractical or impossible due to the additional damage to the neighboring tissues.
D) Crushed, with significant soft tissue damage resulting from the compression. The damage to the cellular tissues may be extensive. Initially it may appear viable, but subsequently die, even though the blood supply was re-established.
B) When the tissue can not be reattached microscopically, it is replaced as a graft ("Composite graft" if more than one tissue type is present, such as skin, bone, and fat). These grafts depend on the regrowth of new blood vessels from the attachment site into the amputated tissue. New blood vessels can be seen under a microscope in as little as four days following the replacement of the amputated piece. This does require that the tissue be kept alive pending this growth. Hyperbaric oxygen is one modality that is used for this purpose. The larger and thicker the reattached piece, the less likely it will be that full revascularization can occur before the tissue dies. When a skin graft is applied to an area, the highest success rate is for "Split-thickness" grafts, that are much thinner than "Full thickness" grafts. Better functional and cosmetic results are obtained with the full thickness grafts, though the "risk-benefit" ratio must always be considered.
THE SIZE OF THE APPENDAGE AMPUTATED (see below about cooling)
THE CARE PROVIDED TO THE AMPUTATED PIECE PRIOR TO REATTACHMENT (also see below about cooling and rapid transport to a treatment facility)
THE SKILL AND EXPERIENCE OF THE SURGEON REATTACHING THE PIECE (self-explanatory)
THE AVAILABILITY OF SUPPLEMENTAL MODALITIES to help the reattached piece survive, such as hyperbaric oxygen therapy, anticoagulant therapy, and/or leeches among others. Reattached appendages do not always need these, but they will occasionally be required to sustain a marginal result.
THE TIME FROM AMPUTATION TO REATTACHMENT (see below)
THE ABILITY TO PERFORM A MICROSCOPIC SUTURING OF BLOOD VESSELS TO RESTORE CIRCULATION TO THE STRUCTURE. Not all amputated appendages can be reattached with the operating microscope. In some cases, the blood vessels feeding the amputated tissues are too small to be repaired.
A) A blood vessel 0.5 mm in diameter can be repaired. Below this, the size of the micro-suture and the needles become too large to make the anastomosis (repair of the blood vessel) possible.
LASTLY, WHETHER THE INJURED PERSON USES TOBACCO. Nicotine is a very potent vasoconstrictor (blood vessel narrowing agent), and can cause a reattached appendage to die from ischemia, even if the blood vessels were attached correctly. With a reattachment, the circulation re-established is not as exuberant as the normal one. It is only intended to keep the appendage alive until the new vasculature can grow back into the tissue (see above).
IN GENERAL, a reattached appendage may have a 100% take of survival, a partial take, or a complete loss. In some cases, a partial take is very acceptable, since the portion that is missing may be able to be replaced from another source (ie. if only skin is missing, it can often be grafted).
With the above in mind, any amputated appendage, by definition has lost its blood supply. If this is not restored in a reasonable period of time, the tissue will die of hypoxia (loss of oxygen) and nutrients. To prolong the time the tissue can be kept unattached, the standard is to cool it as much as possible, without freezing it. Freezing causes the liquid parts of the cells to swell, as ice does in an ice cube container, which ruptures the cell wall, killing the cell. The best way to treat an amputated piece of tissue is to place it dry, into a plastic bag, and seal it. Then place that bag into a second bag filled with iced water. Saline, or salt water should never be used for the liquid, since the freezing point of salinated water is below 32°F, which could result in the above described death by freezing of the cells. Do not add saline to the first bag "to keep the specimen moist". It may lead to maceration of the tissues and make them unreplantable. The tissue will not dry out as long as the first bag is sealed.
The "clock begins ticking" the moment the appendage is amputated. A smaller appendage such as a finger or ear, may be kept viable (alive) for many hours. While there are claims that a specimen has been successfully replanted after 24 hours, the chances decrease significantly with prolonged ischemia (lack of oxygen). A reasonable goal should be 8 hours or less. Extra care must be taken with larger appendages to ensure that the entire limb or structure is kept evenly cold. While the surface may be cold, the interior may be warmer if there is not adequate cooling provided (ie. insufficient iced water to cover the entire area.)
After all of the above is taken into consideration, other factors that may lead to an unsuccessful reattachment have to be considered: The age, and general health of the patient; The condition of the proximal site (the area the appendage was amputated from); The availability of the equipment and/or personnel to actually perform the operation; The willingness of the patient to undergo the procedure and the postoperative rehabilitation.
COVER ILLUSTRATION: Sergii Rodionov