Nail Trephination

What is nail trephination?

Nail trephination is a common, safe way to drain trapped blood from under your fingernail or toenail (subungual hematoma). It requires making a small hole in your fingernail where the blood is seen. Healthcare providers do trephination in a variety of settings, including emergency rooms and urgent care clinics. You should never try to do it yourself.

Subungual hematomas happen when there’s sudden trauma to a fingernail or toenail — for example, you slam your finger in a door or drop something heavy on your toe. We all know what these “ouch” moments feel like.

Your first instinct might be to try and treat a bruised nail yourself. Applying ice (wrapped in a towel) may be all you need. But if the blood under the nail increases in size or the pain continues to get worse, see a healthcare provider. They can decide if you need trephination. They’ll also evaluate your finger or toe for any other injuries — like broken bones (bone fractures) or nerve damage — and make sure you get the treatment you need to properly heal.

What does nail trephination treat?

Trephination is appropriate for treating simple subungual hematomas. This means the nail plate (the hard part of your nail) is still attached to the nail bed (the delicate tissues beneath it). You’ll typically have bruising and pain, but the nail’s still intact.

You may need more extensive treatment (including removal of the nail plate) if you have a subungual hematoma along with:

• Separation of the nail plate from the nail bed.
• Splitting of your nail.
• A deep cut.

Your provider will tell you what’s best in your situation.

When to drain a smashed finger or toe

You should see a provider to drain a subungual hematoma as soon as possible after an injury. The procedure works best within 24 to 48 hours of when the trauma occurred.

How should I prepare for this procedure?

You don’t need to do anything specific to prepare for trephination. But your provider will explain the risks and benefits of the procedure to you before getting started. They’ll also ask for your permission.

What does trephination involve?

To drain a subungual hematoma, a provider will:

• Clean your nail and the surrounding area. They’ll use soap and water to remove any dirt or debris. They’ll also apply a wound-cleansing solution, like chlorhexidine.
• Make a small hole in your nail. Your provider will use a needle, an electrocautery device (which looks like a pencil and has a heated tip at the end) or a special tool designed for trephination. They’ll position the device over the middle of the bruise and use gentle pressure to make a hole just deep enough to release blood. The device will only go through your nail plate (the hard part), not the tissues below it.
• Let blood drain from your nail. The hole in your nail lets the collected blood ooze out. This relieves the pressure and pain. You’ll notice the difference right away.
• Apply a bandage. Your provider will apply a sterile bandage and tell you how to care for your finger or toe as it heals.

How long does trephination take?

Trephination takes just a few seconds. The procedure causes some pain or discomfort in most people. But it’ll be over before you know it. And you’ll feel much better afterward.

What happens after trephination?

You’ll go home right away. Trephination is a quick, outpatient procedure. You may notice drainage through the hole in your nail for the next 24 to 36 hours. This is normal and temporary.

Follow your provider’s instructions for changing bandages and caring for your finger or toe. In general, you should keep the area dry and clean.

What are the benefits of trephination?

Trephination releases trapped blood from under your nail to ease pain and pressure. It’s the tried-and-true treatment for managing painful subungual hematomas.

What are possible complications of trephination?

Trephination rarely leads to complications. But it’s possible to develop:

• An infection (which is treatable).
• A minor injury to your nail bed (which shouldn’t cause lasting effects).

What happens if you don’t drain a subungual hematoma?

Not all subungual hematomas need to be drained. But if the injury is causing you severe pain, that means the blood is causing too much pressure. Without draining the hematoma, you may experience:

• Continued throbbing or severe pain.
• Sensitivity to the touch.
• Permanent damage to your nail, including visible changes like ridges, splitting or changes in your nail shape.
• Loss of your nail.

What can I expect for recovery?

Your nail will still look discolored for weeks (or longer) after trephination, but this is normal. The discolored part will gradually grow out as your nail grows. Simple subungual hematomas usually heal without any lasting changes to the look or feel of your nail, depending on the severity of the injury.

Your provider can tell you exactly what to expect based on the nature of your injury.

When should I call my healthcare provider?

Seek medical care after trephination if you have any signs of infection, including:

• New or worsening red/discolored skin around your nail.
• Swelling.
• Purulent drainage (thick, milky fluid that oozes out of your nail area).
• Fever.

How do I drain a subungual hematoma?

Only a healthcare provider should drain a subungual hematoma. Never attempt to drain it on your own. Doing so could lead to complications like infection, further trauma and delayed healing. You also shouldn’t try to use objects like paper clips to drain your nail. This can cause an infection and further harm. See a trained medical professional instead.