Subungual hematomas can occur in both fingers and toes. They are the result of trauma and blood accumulation under an intact nail plate. Nail trephination is the term used to describe the evacuation of a subungual hematoma. Nail trephination is commonly performed in patients who have significant pain associated with a subungual hematoma. There are a variety of methods available to administer analgesia and methods for performing nail trephination. It should be mentioned, that nail trephination in a patient with a non-painful subungual hematoma is not always necessary.
Cryotherapy provides many benefits to the acutely injured extremity. It is also a good form of analgesia when local anesthetic is not available, the patient is not receptive to receiving a local anesthesia via injection or necessary to provide pain relief.
For those patients who are reluctant or squeamish about getting an injection, immersing the affected digit in a cup of ice water helps to temporally reduced pain. I have them immerse their affected finger in a cup of ice water for about 10 minutes prior to evacuating a subungual hematoma. (For toes, I have them immerse the affected foot in a pan of ice water). This is a great non-invasive and effect way to provide procedural analgesia. While pain relief is not long-lived it does provide enough relief to allow for the subungual hematoma pressure to be released while improving patient comfort. For those who are not interested in waiting for cryotherapy analgesia to take effect, then I preform a digital block with either Xylocaine 1% or Bupivacaine 0.25%.
Pressure relief (Trephination) maneuvers can include, drilling the nail with a #11 scalpel blade or 18-gauge needle, melting the nail plate with a hot paper clip or a battery powered elctrocauter device. However, the use of electrocautery, in the presence of acrylic nails, is contraindicated until the acrylic nail can be removed. The acrylic nail can be flammable and when mixed with an electrocautery heat source could cause a fire to occur. All trephination methods serve the purpose of relieving fluid pressure from under the nail plate and thus pain relief. A loose compressive bandage is used to keep the drill hole(s) patent and allow for fluid drainage. Daily cleaning of the affected finger will keep the wounds clean and nail plate openings patent.
Nail bed Laceration/Tuft fracture
Crush injuries to the distal finger can often result in a Tuft fracture with or without a nail bed laceration and a subungual hematoma. If the subungual hematoma occupies less than 25% of the nail bed area, with or without a nail bed laceration, then a simple evacuation of the subungeal hematoma is warranted. 1, 2 A Tuft fracture can be immobilized in a simple dorsal (or volar) finger splint. If the subungual hematoma occupies greater than or equal to 50% of the nail bed space then I believe this represents a significant nail bed laceration and the nail plate should be removed and any laceration repaired. If the nail plate is intact, I will reattach it with suture, to the nail bed, for protection of the germinal nail matrix and nail bed wound. In the presence of a nail bed laceration associated with a damaged nail plate then, consideration should be given for removal of the damaged nail plate which will facilitated repair of any skin laceration. In a fingertip injury that results in a damage nail plate, nail bed laceration and an associated Tuft fracture (confirmed by x-ray) I would consider this to be an open fracture. 2 This patient should be started on oral antibiotic coverage for 5-7 days and have a splint applied to immobilize their fracture. The patient should also have a have a follow up appointment in 7-10 days for reevaluation of this injury.
A review of the medical literature has indicated that nail trephination should be performed for subungual hematomas smaller than 25-50% of the nail surface. However, more recent studies have indicated that the size of the subungual hematoma, associated nailbed laceration or phalanx fracture (Tuft) do not show a difference in complication rate. Therefore, subungual hematoma evacuation is indicated for any sized hematoma as long as the nail plate edges are not separated from the nail bed. I, II
Clinicians should possess the ability to evaluate and mange patients with fingertip injuries. Subungual hematomas can be easily treated with nail trephination especially for those who are experiencing increased finger pain.
- Roser, SE Gellman H: comparison of nail bed repair versus nail trephination for subungual hematomas in children, J Hand Surg, 1999 Nov 24(6):1166-7
- Dean, B, Becker, G, Little, C: The management of the acute traumatic subungual hematoma: a systematic review, Hand Surgery 2012, 17(1):151-154