In the past I have been told that hair density of 50 follicular unit grafts per square centimeter should not compromise graft survival. However, I was wondering would transplanting hair at 55 FU/cm2 or 65 FU/cm2 compromise vascularity or hair growth yield? Also, is any graft survival compromised leading up to achieving natural density? Cheers.
This insightful information was posted on our hair restoration forum by Dr. Brad Limmer of San Antonio, TX who is a member of the Coalition of Independent Hair Restoration Physicians.
I agree with what has been on the hair loss forum discussion thread “Graft Survival and High Hair Densities” by various members regarding percentage yield. As Coalition member Dr. Charles points out a very important point regarding this question, “there are countless variables that go into this equation.” Some are hair transplant patient dependant and some are hair restoration clinic/technique dependant. Thus, the outcome can be different between patients even though they go to the same clinic.
We have typically approached the problem of yielding densities higher than 50 FU/cm2 by a 2 pass approach. While more conservative than some (who produce nice results), I feel it minimizes 3 important risks to the patient:
1. Less than optimal hair growth
2. The Potential for ridging (dermal fibrosis below the skin – which is basically scar tissue resulting from the multiple recipient sites create in such a small area)
3. Permanent neovascularization (redness that won’t go away – resulting from capillary proliferation during the healing process)
Sorry for the diversion from your question, but the problem of lower yield can often be easily addressed. Ridging and redness can be permanent. Granted this is not always going to occur at high densities, but this had not been seen with follicular unit (FU) micrografting until ultra high densities became more common. It was a problem seen years ago with plugs/minigrafting but is now occasionally being seen again. So while not an absolute contra indication, at least be aware of the possible risks.
Brad Limmer, M.D.