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A Study on Follicular Unit Trauma and Graft Survival

A recent study published in Dermatologic Surgery in May of 2021 compared different types of follicular unit extraction (FUE) graft injuries to see if there was any difference in survival. This was a mouse study where human follicles were transplanted into mouse recipients. In the study, they compared three types of follicular unit injury: paring, fracture, and bulb injury.

Paring refers to laceration of the outer root sheath or dermal sheath of the hair follicle whereas fracture refers to separation of the follicle into two or more pieces. In this study, the authors found that survival rates in the fracture group was the worst (18%). The survival rate in the paring and bulb injury groups was better than those in the fracture group but still significantly lower than the intact group.

This study demonstrates how important it is that hair transplant teams be aware of the need to preserve the integrity of hair transplant grafts, including the bulbs, dermal sheath, and outer root sheath as this can have an adverse effect of the results of the hair transplant procedure.


Comparative Graft Survival Study of Follicular Unit Excision Grafts With or Without Minor Injury.Kwack MH, Kim MK, You SH, Kim N, Park JH.Dermatol Surg. 2021 May 1;47(5):e191-e194