FUSS is performed by removing a strip of donor tissue from the back and sides of the scalp which are genetically resistant to dihydrotestosterone (DHT), the main hormone responsible for androgenic alopecia or genetic hair loss. Each time a strip of donor tissue is removed the scalp becomes tighter and loses elasticity. Thus, reducing the amount of surgeries a patient could have without severely compromising the scalp. The term "stripped out" refers to the patients scalp which can no longer withstand any further donor tissue removal.
FUE is a minimially invasive procedure that involves a hair transplant surgeon removing follicular units one by one with the use of a small punch between the sizes of 0.7 and 1mm in circumference. Generally, due to the nature of FUE, fewer grafts can be excised per surgical session than a typical strip procedure, because of its limitations which include: graft transection, surgical fatigue, donor density and graft quality. Thus, it is recommended for patients with extensive hair loss to opt for strip surgery first.
Why combining FUSS and FUE produce more donor hair for transplanting
By combining both FUSS and FUE, the surgeon is able to extract much more hair in the donor site of a patient than in any one procedure alone. In the old days, a patient would be "stripped out" and no longer be a hair transplant candidate. However, now that both surgical techniques have become ultra-refined a hair restoration surgeon can now extract more hair from a patient who's already been "stripped out" by finishing off with FUE. This provides the patient with a denser and fuller head of hair than ever before.