Trick of the Trade: Hair apposition technique (HAT trick)

Scalp lacerations over hair-bearing areas require wound closure, usually with staples. An alternative technique is the Hair Apposition Technique, also known as the HAT trick. [1, 2] This technique provides a more cost-effective, faster, and less painful approach to scalp laceration repair. Imagine the scalp hairs as suture ties already embedded in the skin.


What are the steps for the HAT trick?

• Perform wound irrigation and a meticulous examination.
• Twist together 3-7 strands of hair on one side of the wound.
• Do the same on the other side of the wound.
  
• Interlock these two hair bundles in a 360-degree revolution. Do not tie a knot.
• Secure the intertwined hair bundles by applying a few drops of a tissue adhesive.
• Repeat as needed to close the length of the laceration.
  
• The patient no longer needs to return for staple removal in 7-10 days. The hair will unravel on its own after a week.
  

Demo of intertwining the 2 hair bundles using a 360-degree revolution twist.

Example of the HAT trick in action.

Contraindications for using the HAT trick:

• Scalp lacerations more than 10 cm
• Grossly contaminated wounds
• Active bleeding from the laceration
• Significant wound tension
• Hair strands less than 3 cm in length

References:
1. Ong ME, Coyle D, Lim SH, Stiell I. Cost-effectiveness of hair apposition technique compared with standard suturing in scalp lacerations. Ann Emerg Med. 2005 Sep;46(3):237-42.

2. Hock MO, Ooi SB, Saw SM, Lim SH. A randomized controlled trial comparing the hair apposition technique with tissue glue to standard suturing in scalp lacerations (HAT study). Ann Emerg Med. 2002 Jul;40(1):19-26.