Our fingers are important for not only our daily lives, but also our jobs and creative activities. Some people accidentally sever their finger fragments while they are handling machines such as electric saws and cutting machines.
There are two severed states depending on how a finger fragment was severed. The severed state in which the finger fragment was completely separated from the patient's hand is referred to as "completely severed." In contrast, the severed state in which the finger fragment was barely connected to the patient's hand through a skin and a tendon is referred to as "imperfectly severed."
The treatments for both the severed states are almost the same. If the finger fragment was completely severed, since it could be cooled with ice water, it could be prevented from being damaged to some extent. In contrast, if the finger fragment was imperfectly severed, since it could not be properly cooled, it could be easily damaged by the patient's body temperature and the ambient temperature. Although the finger fragment was imperfectly severed, a vain of the finger fragment might be connected to the hand. In this case, since a blood flow may be maintained, blood would be prevented from congesting.
The treatment for connecting the severed finger fragment to the hand as much as it was is referred to as "reattachment." A finger fragment that was severed cannot be always reattached. The cross-section of the severed finger fragment should be as sharp and clean as possible.
Generally, if one of situations (1) "severe crushing" in which the finger was crushed and severed, (2) "heat press injury" in which the finger was caught and nipped by a heated machine, (3) state in which nerves and tendons that were teared and removed like strings at a position closer to the hand side than the severed finger fragment side and they are difficult to be sutured, (4) damaged finger fragment in which it has not been properly cooled after it had been severed, and (5) systemic complication occurs, it would be difficult to reattach the severed finger fragment to the patient’s hand. Additionally, since smokers, persons who have high blood pressure, and older persons may have arteriosclerosis that frequently impairs function in blood vessels, especially in small vessels, it may be difficult to inosculate their blood vessels.
If the severed finger fragment is directly placed in ice water, since the cells of the finger fragment would be damaged, it becomes difficult to reattach the severed finger fragment to the patient's hand. It is necessary to clean the severed finger fragment, remove extra moisture from it, and place it in a polyethylene bag containing ice water. If the severed finger fragment has been properly cooled, it could be reattached to the patient's hand unless eight hours have not elapsed after the finger fragment had been severed.
The severed finger fragment can be reattached to the patient's hand in the following steps.
(1) The bone is fixed with a wire.
(2) The flexor tendon that bends the finger and the extensor tendon that extends the finger are sutured.
(3) The nerves are sutured.
(4) The arteries and veins are inosculated.
If blood does not smoothly flow in the arteries, ischemia in which sufficient blood is not supplied to the finger occurs. Although the arteries have been inosculated, if blood does not smoothly flow in the veins, blood will congest in the reattached finger. In these cases, the finger will necrose. To prevent such situations, after the surgery, the patient should be bed rested. In addition, medications to increase blood flow (peripheral vasodilators) and an anticoagulant (heparin) are used so that thin inosculated vessels are not clogged. The patient should take a rest for two weeks after the surgery. After the rest period, the patient should undertake rehabilitation for moving the wrist, elbow, and shoulder other than the finger.
Whether or not the severed finger fragment can be reattached to the patient's hand depends on the severed finger position and state, patient’s systemic state, elapsed time after the injury, and so forth. The sooner the patent undertakes the treatment, the better outcome he or she can have. If a finger fragment is severed, the patient should reach a reliable hospital so as to see a skilled surgeon and have treatment as soon as possible.