modified hair apposition technique

I got a nice email from Dr. John Fowler from Turkey who recently published a modified version of the Hair Apposition Technique (HAT) trick in the American Journal of Emergency Medicine in 2009.

Read more about the traditional HAT trick.

The HAT trick allows for scalp laceration closure by using scalp hair and tissue adhesive glue. Contraindications to this technique for wound closure include hair strands less than 3 cm, because it is difficult to manually manipulate short hair.

Trick of the trade: Modified HAT trick

The modified version of the HAT trick (modHAT) uses Kelly clamps to allow for instrument-manipulation of the hair bundles. This is different from the traditional technique, where the provider twists hair strands manually. The Kelly clamps allow the provider to twist hair strands as short as 1 cm.

modified hair apposition technique diagram

In a study with 67 patients, there were very few complications. One patient developed local alopecia in the area of the laceration. This likely was caused by excess tissue adhesive spilling into the wound itself.

Another noted complication was the tissue adhesive glue not peeling off of the hair after 2 weeks. In 7 of the 67 patients, they cut off the “hair-glue knot”. This likely was because more than 1 drop of glue was applied to each twisted hair bundle. By applying only 1 drop per bundle, the patient can more easily tweeze the glue off with a comb. Bottom line: More is NOT always better.

Karaduman S, et al. Modified hair apposition technique as the primary closure method for scalp lacerations. Amer J Emerg Med (2009) 27, 1050–5.


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


Professor of Emerg Med at UCSF-Zuckerberg SF General. ALiEM Founder @aliemteam #PostitPearls at Bio:
Michelle Lin, MD