New Approach to FUE May Reduce Scalp Trauma by Over 21%

A new study co-authored by the Hair Transplant Institute’s lead surgeon, Dr. Paul Rose, reveals a new approach to follicular unit extraction (FUE) that may reduce scalp trauma by more than 21%. The new technique promises several key benefits for men and women seeking surgical hair restoration, including:

  • Accelerated healing process
  • Reduced appearance of post operative scars
  • Minimizing of any potential blood loss

Understanding Scalp Trauma

Although considered to be a minimally invasive procedure, FUE inevitably causes some degree of damage to the scalp. Postoperative scars are much less visible compared to the long, linear scar left by traditional strip donor procedures. Nevertheless, FUE leaves tiny circular dots that are a reddish color. Moreover, these scars tend to vary in size.

How Extraction Affects Scar Size, Shape

In the study co-authored by Dr. Rose, surgeons demonstrate that skin injury is significantly impacted by outgrowth angle, or the angle at which the donor hair grows away from the scalp. To safely remove a follicular unit, the extraction tool (punch) must be aligned with the general direction in which the hair grows. Thus, the angle at which the punch instrument enters the skin changes with the outgrowth angle of each follicular unit.

If the donor hair happens to grow perpendicular to the skin, the punch approaches the scalp at a 90-degree angle to extract the follicular unit. This is the best case scenario; a perpendicular approach means less friction, reduced trauma, and a less noticeable circular scar.

Outgrowth angles are rarely 90 degrees, however. And when punch instruments extract follicular units with an acute outgrowth angle (less than 90 degrees), a more shallow approach is taken that creates more friction, skin damage, and a larger elliptical scar.

The Solution: Better Angles, Less Trauma.

In the study, surgeons note that saline injections provide two important benefits during FUE hair transplant: Firmer skin, and more predictable outgrowth angles. Under these conditions, surgeons calculate that a punch instrument can be up to 56.25% larger while reducing skin injury by 21.98% (i).

“…it should be emphasized that by injecting normal saline, the skin is stretched,” the team writes. “So once normal saline has drained away, the skin returns to normal […] This important fact results in accelerating the healing process, decreasing the degree of scarring, and minimizing any possible blood loss.”

While follow up studies are needed, the use of saline injections during FUE hair transplant procedures promises to enhance patient experience and overall results.


(i) Zontos G, Rose P, Nikiforidis G. A mathematical proof of how the outgrowth angle of hair follicles influences the injury of donor area in FUE harvesting.