Overview of Nail Biopsy
A nail biopsy is a procedure that skin doctors, or dermatologists, use to identify different skin and nail diseases. This biopsy can be done in several ways, not only limited to areas like the nail plate (hard, protective part of the nail), nail bed (skin underneath the nail), nail fold (skin around the sides of the nail), and nail matrix (where new nail grows from).
The type of problem the doctor suspects will usually decide where the biopsy is taken and how it’s done. The nail matrix is a very sensitive area and has its own risks and side effects when biopsied. But even with this, most nail biopsies have little to no risk of causing permanent damage to the nail.
Anatomy and Physiology of Nail Biopsy
The nail matrix is a crescent-shaped section found at the base of the nail that produces the nail plate, the hard and shiny substance of the nail. If the nail matrix is harmed, it could lead to scarring and abnormalities in the nail. It’s divided into two parts, the proximal matrix and distal matrix. The proximal matrix makes the top layer of the nail, while the distal matrix makes the bottom layer. A biopsy, a medical test involving the removal of tissue for examination, of the distal matrix is less likely to lead to scarring. The tissue beneath the nail plate is quite thin, meaning it’s easy to reach the bone of the tip of the finger. It’s unlikely that the extensor tendon, the cord-like part that helps move the fingers, would be damaged during an average biopsy.
The source of blood for the area around the nail comes from arteries that run along the inside and outside of the fingers. The veins in this area generally follow the same path as these arteries. The nerves that supply sensation to the 2nd, 3rd, and 4th fingers are known as the volar proper digital nerves, while the 1st and 5th fingers are supplied by the dorsal proper digital nerves.
Why do People Need Nail Biopsy
A nail biopsy is a medical procedure doctors use to understand nail conditions better. These conditions could be infections, inflammation (swelling or redness), autoimmune diseases (where the body’s immune system mistakenly attacks its own cells), trauma (injury), or cancer-related. Usually, doctors choose to do a nail biopsy when the problem is specifically located in and around the nail.
A nail biopsy can help diagnose several common nail problems. These include onychomycosis (a fungal infection of the nails), psoriasis (a skin disease that causes red, itchy, scaly patches), lichen planus (a condition causing small, itchy, flat bumps on the skin), twenty-nail dystrophy (a condition where all 20 nails become rough and pitted), melanonychia (darkening of the nails), melanoma (a type of skin cancer), and benign (noncancerous) tumors of the nail.
When a Person Should Avoid Nail Biopsy
There are a few situations where a doctor might decide not to do a nail biopsy. If someone has peripheral vascular disease, which affects blood circulation, or arterial compromise, which means their arteries aren’t working properly, these could make the procedure too risky. Like with any medical procedure, the doctor should always explain what it involves and get permission from the patient before starting.
Equipment used for Nail Biopsy
An antiseptic is a disinfectant used for cleaning your skin before the procedure. These can be alcohol or chlorhexidine, but other types could also be used effectively for a nail biopsy.
For numbing your skin during the biopsy, a local anesthetic called 1% lidocaine solution is often used. This prevents you from feeling pain during the procedure. To lessen pain when the anesthetic is applied, a mixture called sodium bicarbonate (8.5% solution) could be added to the lidocaine. Epinephrine is also sometimes used to control bleeding during the procedure. However, it’s generally used with caution in patients who have peripheral arterial disease, a condition that affects the blood vessels outside your heart and brain. Though quite safe for most people, it’s less commonly used for numbing fingers or toes.
Instruments required for the biopsy include a tourniquet (a band that controls blood flow), a punch or shave tool for cutting the skin, nail clippers, a scalpel (a small surgical knife), tissue scissors, a needle driver (tool to manipulate sutures), and a nail elevator (tool to lift the nail).
To help stop bleeding, a hemostatic agent such as aluminum chloride is normally used. Something called a Hyfrecator could be used too, but it might cause changes in the structure and function of the nails when used close to the nail’s root or matrix.
After the procedure, your wound will be dressed with sterile gauze, and sutures that do not dissolve on their own may be used to close the wound. A special kind of bandage, called non-stick wound dressing, is then applied to your wound, often along with sterile petroleum ointment. Studies have shown that petroleum jelly works just as well as antibiotic ointments in preventing wound infection and promoting wound healing, and it’s less likely to cause an allergic reaction.
Who is needed to perform Nail Biopsy?
A nail biopsy is usually done by a doctor alone. But sometimes, the doctor may work with a nurse or a medical assistant. Having someone else there can make things go more smoothly. They can help with tasks like cutting stitches, getting any materials that may be needed during the procedure, stopping bleeding, and preparing the tray for the biopsy.
Preparing for Nail Biopsy
Before a skin test or applying numbing cream, it’s crucial to clean the test site and the surrounding skin with a germ-killing solution. The numbing cream, which is a local anesthetic, is applied as a nerve block, which can be either a type of block administered to the fingers or a wing block. After putting on the numbing cream, a 10-15 minute wait time is enough to make the entire area lose sensation. During this time, the finger can be placed in a bowl of water to soften the nail, making the skin test easier. Then, a device to control blood flow is put on the finger to reduce bleeding during the procedure. This device, known as a tourniquet, should be left on for maximum of 15 minutes to avoid damaging nerves or blood vessels. Many skin doctors prefer to keep it on for less than 5 minutes to be extra safe.
For some skin testing methods, it is necessary to remove the nail before testing the lesion, which is an abnormal area or growth on the skin. A common tool used for nail removal is a nail elevator. This tool is gently inserted under the part of the nail close to the finger to loosen the nail from the skin fold above it. The elevator is then slid under the part of the nail farthest from the finger and pushed towards the finger. This action detaches the nail from the underlying nail bed and the nail matrix, which is where new nail cells are produced.
How is Nail Biopsy performed
There are two popular techniques for numbing the nail area during a procedure: the proximal digital block and the distal digital block. Both these methods involve injecting a local anesthetic, which numbs the area, into the base of the finger. The proximal digital block is a wider-ranging nerve block that takes around 10 to 15 minutes to take effect, and a medical tool called a tourniquet can be used to reduce bleeding and keep the anesthetic in place. The distal digital block, on the other hand, is quicker-acting as it targets a specific location close to the nail folds, and requires a lesser amount of anesthetic. Ropivacaine 1% is usually the preferred anesthetic due to its long-lasting effect, but any local anesthetic can be used effectively.
Depending on the problem, doctors may need to perform a biopsy, which is the removal of a small amount of tissue for examination. There are four main types of nail biopsies:
Nail plate biopsy: This is quite simple and is generally used if the doctor suspects a fungal infection. A small part of the nail plate is removed with scissors or a nail clipper. This usually doesn’t require any anesthesia. However, if a part of the nail needs to be removed, then a local anesthesia will be needed and effort will be made to stop any bleeding. This method rarely results in scarring.
Nail bed biopsy: This is done if the doctor is trying to diagnose skin conditions under the nail plate. The nail must often be removed (avulsed) before taking a sample. This sample is taken through a punch or cut biopsy tool. If the sample is bigger than 3 mm, a stitch might be required. Sometimes, the nail might separate from the skin early as it regrows.
Nail fold biopsy: This is conducted on the folds at the sides of the nail to diagnose conditions around the nail. The affected part is cut out using different tools. Sometimes, a tool called a nail elevator might be used to elevate the surrounding nail fold for easy removal of the lesion. Again, this method rarely results in scarring and the cut can heal naturally.
Nail matrix biopsy: This is usually done if the doctor believes that the patient might have a skin cancer called melanoma. The sample is taken after the nail is partially or entirely removed. The sample is obtained through punching or cutting. It’s important to remember that samples from this part of the nail should be obtained horizontally rather than longitudinally. The area might need to be stitched up for cosmetic reasons and to aid regrowth of the nail. This method might leave a scar and cause the nail to grow in a split manner.
Longitudinal nail biopsy: This method is employed for larger lesions, particularly those located at the sides of the nail. It’s often used when a full sample of the nail might be required to diagnose the problem. This procedure takes samples from different parts of the nail at the same time providing the most amount of information. It involves making incisions along the nail fold and removing the tissue up to the bone-deep. Stitches are often used for better healing and appearance. This is the most invasive of all nail biopsy techniques and has the highest risk of scarring and nail deformation.
After the biopsy is done, it’s important to stop any bleeding. Tools like aluminum chloride, Monsel’s solution can be used or even simple pressure by hand can stop the bleeding. Once the bleeding has stopped and the biopsy site is cleaned with either alcohol or saline, it’s covered with sterile petroleum and a non-sticky dressing.
Possible Complications of Nail Biopsy
Before the procedure begins, the doctor should explain what to expect to the patient. There are some potential risks that could happen from this procedure, including bleeding, infection, changes to the nail’s appearance and feel, the chance that the biopsy does not provide a clear diagnosis, pain after the procedure, and a temporary difficulty in using the finger or toe from where the biopsy is taken. It’s very important for the doctor to maintain a clean environment during the procedure to prevent a bone infection, as most biopsies involve getting a small sample from the bone underneath the nail.
Possible complications could include:
* Bleeding
* Pain after the procedure
* Infection
* Problems with the way the nail grows back (such as a split nail, red streaks in the nail, or changes in the nail’s texture and shape)
* Reaction to lidocaine, a commonly used local anesthetic
* Feeling faint or lightheaded (this can sometimes happen when the anesthetic is injected)
After the procedure, the patient should be told to keep their finger or toe raised for the next 48 hours. This helps prevent swelling that could cause the bandage to become too tight, which could interfere with blood flow to the finger or toe.
What Else Should I Know About Nail Biopsy?
A nail biopsy is a procedure where a small part of your nail is removed and examined under a microscope. It’s used along with understanding your symptoms to confirm what’s causing the nail issue. The details obtained from this detailed examination help the doctor figure out the exact problem or disease affecting your nails. Once the issue is diagnosed correctly, your doctor can start deciding what treatment would be best for you.
