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.

 

Michelle Lin, MD
ALiEM Founder and CEO
Professor and Digital Innovation Lab Director
Department of Emergency Medicine
University of California, San Francisco
Michelle Lin, MD

@M_Lin

Professor of Emerg Med at UCSF-Zuckerberg San Francisco General. Founder of ALiEM @aliemteam #PostitPearls https://t.co/7v7cgJqNEn
Michelle Lin, MD