Johns Hopkins Cutaneous Nerve Laboratory Skin Biopsy Procedure

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Johns Hopkins Cutaneous Nerve Laboratory Skin
Biopsy Procedure
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Step 1- Prepare the Area to be Biopsied
After the patient has been gowned, a clinical
history has been taken, and the procedure
explained, the area of skin where the biopsy is
to be performed is prepared with an alcohol swab
to insure sterile conditions.
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Step 2 Anesthetize the Skin
Once the skin has been prepared with alcohol, the
next step is to anesthetize the area to be
biopsied by injecting a solution of Lidocaine
(HCL 1 and Epinephrine 1100,000) just under the
epidermis (subepidermally) using a ½ cc
Tuberculin Syringe. The injection should
continue until a bleb or bubble has formed
under the skin greater than 3mm in diameter. The
injection will burn slightly (much like a bee
sting) due to a pH difference between the skin
and the solution. The slight burning will
quickly subside and the site will become numb.
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Step 3 Check for Numbness
After the initial Lidocaine injection the area to
be biopsied should be checked to insure that the
skin is properly anesthetized. The point of the
syringe is used to poke the area of the bleb or
bubble. Great care should be taken not to force
the needle into the skin. The test site should be
somewhere around the periphery of the bleb. Both
of these precautions insure a viable biopsy for
diagnosis later. If the patient experiences
neither pain nor sharp sensation, the biopsy
continues. A pressure sensation is normal and
expected but there should be no pain. If the
area requires more anesthesia, another injection
(with a new syringe) is made until the patient is
comfortable.
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Step 4 Biopsy the Skin
After the area to be biopsied is properly
anesthetized, the biopsy continues. Using a
sterile 3mm skinpunch, the physician applies
pressure and twisting in a drilling motion
until the conical blade of the skinpunch has
pierced the epidermis of the skin. The blade
should be about ½ exposed. It is normal for the
patient to experience a pressure and twisting
sensation but no pain.
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Step 5 Remove the Skinpunch
After the blade has sufficiently cored or
carved out a 3mm cylinder of skin the skinpunch
is removed. It is normal for the area to bleed
after the punch is removed. Excess blood is
wiped off with sterile 2 x 2 gauze to expose the
biopsy site. The entire process resembles the
cookie cutter effect. The only purpose of the
skinpunch is to core the skin and not to remove
the biopsy, much like a cookie cutter.
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Step 6 Excise the Biopsy
When the skin has been cored and cleared of
excess blood, the next step is to remove the
biopsy from the rest of the skin. Great care
should be taken not to damage the epidermis by
crushing it with forceps or by cutting it with a
scalpel unnecessarily. The physician uses the
forceps to grab the dermis of the cored skin,
pulls up the core to reveal excess dermis and
subdermal fat, and uses the scalpel in one or two
cutting motions to cut the cored skin free.
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Step 7 Excise the Biopsy (cont.)
Notice the position of the scalpel during the
excision process. The scalpel is placed under
the forceps and is moved in the opposite
direction of the forceps pulling on the dermis.
This motion stabilizes the biopsy and aids in
preventing a chopping or slicing affect when
trying to free the biopsy. The physician simply
utilizes one or two strokes of the scalpel to
excise the biopsy with a clean cut.
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Step 8 Bandage Biopsy Site
Once the biopsy has been removed from the skin
there will usually be some degree of bleeding
which should be absorbed with sterile 2 x 2
gauze. The biopsy site is then covered with a
standard Band-Aid and possibly fortified with
sterile gauze and paper tape if the bleeding
threatens to soak the Band-Aid and/or the
patients clothing. This hole in the skin will
continue to bleed for the rest of the day and may
or may not form a scab in a few days time.
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Biopsy Site Care
The biopsy site should be kept clean. The site
should not be submerged in water (i.e. no
swimming, hot tubs, baths, etc) for a few days.
The bandage should be changed at least once a day
and should be changed if it should become wet or
damp. Once a substantial scab has formed, or new
skin beings to grow over the area and bleeding
has stopped, the bandage can be removed. In the
long term, minimal scaring may occur. In most
cases the biopsy site is indistinguishable within
a few months. In a few instances the biopsy site
may form a protrusion or bump but continue to
heal normally.