Preparation

• Goggles
• Sterile gloves
• Sterile gauze
• Sterile drape
• Chlorhexidine (or other approved cleansing agent)

Heat Method

• High-temperature loop cautery

Drilling Method

• 18-gauge needle

Procedure Steps

Step 1: Health history and physical assessment

Health history:

• Assess the mechanism of injury

Physical assessment:

• Circulation, sensation, and movement distal and proximal to the wound
• 2-point discrimination / sharp/soft discrimination
• Pulses and capillary refill
• Range of motion and strength against resistance of all body parts surrounding the wound site unless contraindicated by other injuries or existing pathology
• Pain
• Consider X-rays to assess for a distal phalanx fracture if the subungual hematoma covers more than 50% of the nail plate

Step 2: Position the patient

• Position the patient for comfort.
• Place the hand or foot with the palmar or plantar surface on a supportive surface.

Step 3: Cleanse the area

• Cleanse the skin with chlorhexidine using a circular motion to loosen and remove bacteria and debris.
• This procedure should be done using sterile technique whenever possible.

Step 4: Trephination

Heat Method

Pain and/or burns can be avoided by applying gently pressure with repeated, quick motions versus prolonged constant pressure until blood drainage is observed

a. Hold the cautery stick perpendicular to the nail plate
b. Heat the cautery stick loop
c. Make the hole(s) at the base of the nail or in the center of the hematoma
d. Touch the hot end to the nail plate and press the tip through
e. Once the tip goes through the nail plate and reaches the hematoma, the blood cools the hot
end, preventing damage to the nailbed
f. Apply pressure to the nail and finger or toe to drain the hematoma

Drilling Method

Take care not to penetrate the nail bed with the needle.

a. Hold the need perpendicular to the nail plate
b. Make the hole(s) at the base of the nail or in the center of the hematoma
c. Apply firm pressure to the nail plate while turning the needle in a circular motion between
your thumb and index finger
d. Release the pressure with the needle when blood return is seen from the hole.
e. Apply pressure to the nail and finger or toe to drain the hematoma

Step 5: Reassess for pain

Anesthesia is not typically required for the procedure, but a digital nerve block may be performed following trephination if significant discomfort remains.

Step 6: Apply antibacterial ointment

Antibacterial ointment (e.g., bacitracin) should be applied over the trephination site, then dressed with gauze or an adhesive bandage.

Aftercare

• Avoid soaking the finger and keep dry for 48 hours, then clean with soap and warm water.
• Keep the finger elevated above the level of the heart to prevent pain and throbbing.
• Prepare the patient that the nail may fall off in the days after trephination.

Patient Education

Follow-up

Follow-up is not typically required following subungual hematoma drainage. The patient should be instructed to monitor for signs and symptoms of infection and to return if present.

Key Takeaways

• The cautery method is preferred of the drilling method due to the risk of trauma if the needle penetrates the nailed.
• Drainage of a subungual hematoma is not required if pain is not present.
• Drainage does to speed up healing or prevent infection.
• Anesthesia is not typically required for this procedure.
• Multiple holes may be required to adequately drain the hematoma.