Over the past 20 years Dr. Beehner has carried out many research studies in hair transplantation. In 1997 in Barcelona, Spain he was first awarded the Annual Research Grant to conduct a study on growth of minigrafts centrally in large hair transplant sessions. He received four more ISHRS research awards in the years since then. He has presented over 50 lectures worldwide regarding the findings of his research. In October of 1999 at the annual ISHRS meeting in San Francisco, he was awarded the Platinum Follicle Award, given each year to the physician carrying out the best clinical research in the science of hair restoration surgery.
In both 2000 and 2002, he was again awarded a Research Grant by the ISHRS at their annual awards dinner. A brief description of these and other research studies will follow. For those prospective patients desirous of being considered as part of one of these studies, just let us know. As a rule, we only use patients who possess totally bald areas on top of the head (so that existing hairs don’t have to be subtracted out in our counting of hairs) and darker colored hair without any gray hairs in the back donor area.
a. Hair Growth in “Chubby” vs. “Skinny” Follicular Unit Grafts
This study was published in l999 in both Dermatologic Surgery and in Hair Transplant International.
In this study, intact one and two-hair follicular units were cut in two different ways: In one group, a generous amount of surrounding fatty tissue was left, both around the hair shaft and beneath the follicle itself, and these were termed the “chubby” grafts. In the second group, the grafts with the same number of hairs were trimmed very close to the hair shaft structure, removing as much fatty tissue as possible.
The results showed that slightly less than 100% of the “skinny” grafts grew hair, and there was a 133% growth of hair from the “chubby” ones, a results explained most easily by assuming the presence of hidden “telogen” hairs in the surrounding tissue that was left.
b. Hair Growth in “Intact” Follicular Unit Grafts vs. “Non-intact” Grafts
This study was first presented at the annual meeting of the International Society of Hair Restoration Surgery in Washington D.C. in September of 1998 (results on one patient), and the final report of the study (on a total of three patients) was presented at the ISHRS Annual Meeting in San Francisco in October of 1999. It is presently being submitted for journal publication.
In this study on three separate men, a zone of 60 “intact” F.U.’s was compared for hair growth with a zone of 60 “non-intact” grafts, produced by splitting down between two adjacent F.U.’s and including the intervening connective tissue as part of the graft.
The results showed that at 9 months, there was no statistical difference in the amount of hair grown by both methods. The conclusion reached by this study is that there appears to be no “magical” inherent property in the Follicular Unit which holds an advantage for hair growth over grafts that are simply carefully “cut to size.”
c. Scalp Reduction “Stretch-back” Study
This study was started in 1997 and completed in 2001. In it Dr. Beehner followed 10 scalp reduction patients over a 1-2 year period of follow-up. The infrequent use of this procedure in hair restoration surgery is the reason for the prolonged nature of the study.
In the study, each man who is was selected for a scalp reduction procedure had all three of the following criteria fulfilled:
A scalp reduction fit the overall goals that the patien thad in mind in seeking out hair restoration.
Tattoo marks (gray colored) were placed within the hair-bearing areas at the side of the scalp fringes at the time of the procedure and the distance between them was measured. These distances were again measured at the end of the procedure, and then again a few months later. The difference between the “after the operation” distance and the distance later on defines the length of stretchback that occurred. This length taken as a percentage of the original width of tissue removed gives a “stretchback percentage.” The overall stretchback percentage was 37% for these ten cases, which is much higher than has been reported in the past for this procedure.
d. Graft-placement Dessication Study and Hair Stress Study (March 2000)
This study was conducted in March of 2000 in Orlando, Florida at the annual live surgery workshop of the World Hair Society and ISHRS.
The study followed the hair growth success of identical grafts piled in the usual amount of moisture on the finger of an assistant’s finger, with the grafts placed 20 seconds apart over a 15 minute period of time. The goal of the study was to find out what the threshold was for graft survival over time. The study showed that hairs grew all the way out to 15 minutes, but the percentage was moderately diminished in those hairs placed after 10-12 minutes on the assistant’s finger. Also, the quality of some of the hairs placed later was slightly thinner.
In the second part of the study, one group of 2-hair FU grafts were kept refrigerated at 40 degrees for five hours and another group of grafts were kept moist in saline at room temperature. There was almost a six hour interval between harvesting and placement of these study grafts. In this part of the study, the FU grafts were left sitting on the finger for 5 minutes before starting the every-20 second placing of the grafts. Thus they were placed up every 20 seconds up to 20 minutes. There was a dramatic difference between the number and the quality of the hairs growing in these two rows after 10-12 minutes. Hairs that had sat on the assistant’s finger for 20 full minutes grew in the “cold” set of grafts, but fared much more poorly in the room temperature group.
e. Study of Various Stress Factors on Graft Growth
In this study, which was performed at the 2001 Orlando ISHRS live-surgery workshop and also on a second patient back in our Saratoga office, we looked at 6 different “stress factors” as they affected hair growth. The stresses were as follows: “Soft crushing” of the follicle bulb, “hard crushing” of the follicle bulb, “hard crushing” of the follicle bulge area, immersion of the grafts for 30 seconds in 1% hydrogen peroxide, immersion of the grafts for 30 seconds in 3% hydrogen peroxide, lying out on dry gauze for 16 minutes. The final results showed only minimal reduction in hair survival for those that were dried, immersed in 1% peroxide, and those “soft crushed” at the bulb. There was moderately severe reduction in hair growth in those grafts that were immersed in 3% hydrogen peroxide and those “hard crushed” at either the bulge area or the bulb. This study was presented at both the 2001 Mexico ISHRS meeting and in summary form at the 2002 meeting in Chicago.
f. Growth of Hair in Centrally Placed Minigrafts in Large Sessions
This study was presented at the ISHRS annual meeting in San Francisco in October of 1999.
It was started two years previously, at which time Dr. Beehner used slightly larger minigrafts (1.8 and 2.0mm diameter) in the central zones. In each of 15 patients a small 2cm x 2cm square area in the center was marked off, and the large minigrafts placed inside this zone were marked and their hairs counted. 4-6 months later the growth of the hairs in these grafts was counted. In conjunction with the above, a temperature study of the subcutaneous tissue in various areas of the scalp was carried out to see if a vascular gradient developed after several transplant sessions.
The conclusions were as follows: 93.5% of the hairs placed in these large minigrafts in the central-most zone at the time of a third transplant session grew. In “virgin” heads, before any transplanting had been done, there appeared to be no consistent gradient of temperature difference between the forehead and the center of the scalp. In the 8 patients studied at the time of their third session, in the majority (5 of 8) there was a clear gradient of increased temperature in the forehead and a reduction of temperature as the central scalp was approached. This would hint at the conclusion that repeated hair transplant sessions do reduce blood supply to the central scalp.
g. Limited Depth Recipient Sites, with both F.U.’s and Minigrafts
In this study, a totally bald scalp (Norwood Class VI)was divided into four zones, two of which were filled in with dense F.U.’s and two were filled in with dense minigrafts. Each of these two groups (the F.U.’s and the minigrafts) were then transplanted in each of these two recipient site depths in two separate zones, one half with “minimal depth” recipient sites, and one half with “full depth” recipient sites.
The patient was evaluated 6 months after each procedure to evaluate hair growth, scalp temperature probe readings (vascular circulation), photographic documentation, and 6 months after the last procedure, biopsies of each of the four zones to assess histology.
This study encompassed three transplant sessions six months apart and took two years to complete. The results were reported at both the annual 2001 meeting in Mexico and at the 2002 Chicago meeting.
The conclusions from the study were as follows: In general, the grafts planted in “full-depth” recipient sites grew the best. Also, the hair survival was greatest for minigrafts as compared to FU’s after three sessions (85.5% for minigrafts at full depth and 57% for FU’s at both limited and full depth). After only one session, both FU’s and minigrafts grew almost 100% of the hairs. It was only with repeatedly going in between the grafts to transplant more, that the percentages went down, dramatically so with the FU’s. The photographic documentation showed that after one session the minigrafted zones appeared more dense, but were somewhat more detectable as being “tufty.” After 2 and 3 sessions, this difference disappeared, and one year after the last session all areas looked equal in density and in being undetectable. Temperature studies showed no changes until the final check one year later, at which time, using measurement at the deepest level of the scalp, there was a lower temperature in the “full depth” zones and in the virgin crown also. Biopsy results showed that there was slight increased “fibrosis” (scarring) and cellular infiltrate in the “full depth” sites. This study will be written up for publishing in Dermatologic Surgery Journal also.