10.02 Superficial Finger Tip Avulsion
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agk's Library of Common Simple Emergencies

Presentation
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The mechanisms of injury can be a knife, a meat 
slicer, a closing door, a falling manhole 
cover, spinning fan blades, or turning gears. 
Depending on the angle of the amputation, 
varying degrees of tissue loss will occur from 
the volar pad, or finger tip.

What to do:
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- X ray any crush injury or an injury caused by 
    a high speed mechanical instrument, such as 
    an electric hedge trimmer.
- Consider tetanus prophylaxis.
- Perform a [digital block] to obtain complete 
    anesthesia.
- Thoroughly debride and irrigate the wound.
- When active bleeding is present, provide a 
    bloodless field by wrapping the finger from 
    the tip proximally with a Penrose drain. 
    Secure the proximal portion of this wrap 
    with a hemostat and unwrap the tip of the 
    finger.
- On a less than one square centimeter 
    full-thickness tissue loss, apply a simple 
    non-adherent [dressing] with some gentle 
    compression.
- Where there is greater than one square 
    centimeter of full-thickness skin loss 
    there are three options that may be 
    followed:
    - Simply apply the same non-adherent 
        dressing used for a smaller wound.
    - If the avulsed piece of tissue is 
        available and it is not severely 
        crushed or contaminated, you can 
        convert it into a modified full- 
        thickness graft and suture it in place. 
        Any adherent fat and as much cornified 
        epithelium as possible must be cut and 
        scraped away using a scalpel blade. 
        This will produce a thinner, more 
        pliable graft that will have much less 
        tendency to lift off its underlying 
        granulation bed as the cornified 
        epithelium dries and contracts. Leaving 
        long ends on the sutures will allow you 
        to tie on a compressive pad of moist- 
        ened cotton that will help prevent 
        fluid accumulation under the graft. A 
        simple finger tip compression dressing 
        can serve the same purpose.
    - With a large area of tissue loss that has 
        been thoroughly cleaned and debrided 
        and where the avulsed portion has been 
        lost or destroyed, consider a thin 
        split-thickness skin graft on the site. 
        Using buffered 1% xylocaine, raise an 
        intradermal wheal on the volar aspect 
        of the patient's wrist or hypothenar 
        emminence until it is the size of a 
        quarter. Then, with a #10 scalpel 
        blade, slice off a very thin graft from 
        this site. Apply the graft in the same 
        manner as the full thickness one 
        (above) with a compression dressing.
- In infants and young children, fingertip 
    amputations can be sutured back on in their 
    entirety as a composite graft (ie, contain- 
    ing more than one type of tissue). In older 
    children and adults, composite grafts will 
    usually fail, and therefore is is important 
    to "defat" the severed portion as noted 
    above so that it is more likely to survive 
    as a full-thickness skin graft.
- When the loss of soft tissue has been 
    sufficient to expose bone, simple grafting 
    will be unsuccessful and surgical consult- 
    ation is required.
- Schedule a wound check in two to four days. 
    During that time the patient should be 
    instructed to keep his finger elevated to 
    the level of his heart and maintained at 
    rest.
- Apply a protective four-prong splint for 
    comfort.
- Unless the bandage gets wet, a dressing 
    change need not be done for seven to ten 
    days. Even then, the innermost layers of 
    gauze may be left in place if the wound 
    appears to be clean and not infected. 
    Always have the patient return immediately 
    with increasing pain or other signs of 
    infection.
- If the wound is contaminated, a 3-5 day 
    course of an antibiotic like cephalexin 500 
    mg tid may be effective prophylais, but 
    antibiotics are not routinely required for 
    associated phalanx fracture.
- Prescribe an analgesic such as acetaminophen 
    plus hydrocodone 7.5 mg or 10 mg.

What not to do:
---------------

- Do not apply a graft directly over bone or 
    over a potentially devitalized or a 
    contaminated bed.
- Do not attempt to stop wound bleeding by 
    cautery or ligature, which are likely to 
    increase tissue damage and probably 
    unecessary. Do not forget to remove any 
    constricting tourniquet used to obtain a 
    bloodless field.

Discussion:
-----------

The finger tip, being the most distal portion 
of the hand, is the most susceptible to injury, 
and thus the most often injured part. Treating 
small and medium-sized finger tip amputations 
without grafting is becoming increasingly 
popular. Allowing repair by wound contracture 
may leave the patient with as good a result and 
possibly better sensation, without the 
discomfort or minor disfigurement of taking a 
split thickness graft. On the other hand, 
covering the site with a graft may give the 
patient a more useful and less sensitive 
fingertip within a shorter period of time. 

Unlike the full-thickness graft, a thin 
split-thickness graft will allow wound 
contracture and thereby allow for skin with 
normal sensitivity to be drawn over the end of 
the finger. The full-thickness graft, on the 
other hand, will give an early, tough cover 
which is insensitive but has a more normal 
appearance. The technique followed should be 
determined by the nature of the wound as well 
as the special occupational and emotional needs 
of the patient. Explain these options to the 
patient, who can help decide your course of 
action.

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