EM Notes @ Jack CF Chong (張志華): Trephination of Subungual Hematoma

Trephination of Subungual Hematoma

Overview

Trephination is the controlled creation of a small opening in the nail plate to decompress a painful subungual hematoma.
A subungual hematoma is blood trapped beneath a fingernail after trauma.
Decompression can rapidly relieve pressure and throbbing pain.
The procedure is most useful when the hematoma is painful and the nail plate is intact and adherent to the nail bed.

Examine and document:
- Neurovascular status.
- Sensation and range of motion.
- Nail stability.
- Lacerations and contamination.
- Evidence of fracture.
Consider radiographs after a crush injury or with significant tenderness.
Seek hand-surgery assessment rather than simple trephination when there is:
- A displaced fracture.
- A disrupted or avulsed nail plate.
- Gross contamination.
- A suspected complex nail-bed laceration.

Obtain consent and clean the nail.
Anesthesia is often unnecessary because decompression is brief, but a digital block can be offered.
Create 1 or more small openings over the hematoma with electrocautery or a sterile needle.
Avoid excessive depth and contact with the nail bed.
Allow blood to drain. Gentle pressure may help.
Irrigate when needed and apply a nonadherent dressing.

Keep the digit clean and dry.
Change the dressing as instructed.
Use elevation, ice, and analgesia as needed.
Drainage may continue for 24 to 48 hours.
Routine antibiotics are generally not required for an uncomplicated injury. Management may change with an open fracture, contamination, immunocompromise, or bite injury.
Address tetanus status when indicated.
Advise urgent reassessment for increasing pain, redness, warmth, swelling, pus, fever, numbness, or impaired motion.
The nail may remain discolored or eventually shed. Regrowth takes months.

Simple trephination is a focused decompression procedure for a painful subungual hematoma with an intact, adherent nail plate.
Evaluate for associated fracture, nail disruption, contamination, and complex nail-bed injury before proceeding.
Local protocols and specialist advice should guide atypical injuries.