When a scalp is shaved and magnified, it is noted that the hair does not come out only as closely-spaced, single hairs. Instead, the hair exits the scalp in small bundles. These are follicular units. Although some follicular units do consist of a single hair, the majority are 2 and 3 hair units. In scalps with more density, there will also be 4 hair follicular units. These follicular units are distinct units under the skin also. Each unit consists of hair roots closely surrounded by small glands, blood vessels, nerve fibers, and a connective tissue sac making a small independent package. We now realize that if these units are damaged during removal or dissection, the hair may grow poorly. It is important to dissect in the loose tissue between the follicular units. A dissecting microscope is necessary to accurately dissect between these follicular units with minimal damage.
Before follicular unit transplantation, grafts were dissected in random sizes and without magnification. The smaller grafts (not the 4 mm plugs) are called minigrafts and micrografts.
Minigrafts consist of 3 to 10 hairs while micrografts consist of 1 to 2 hairs. These grafts are cut without regard to maintaining the integrity of the follicular units. Follicular units are routinely broken apart during the naked eye dissection. Graft sizes are determined strictly by the size of the recipient holes being placed in the scalp. Generally, a small plug is removed leaving a hole behind or a stab incision is made with a scalpel blade. The grafts are then sized to match the size of the hole in the scalp.
Mini and micrografting is a much better method of transplantation than the large plugs that proceeded them, but it still has the same problem of giving a “pluggy” or “corn row” appearance. Additionally, an occasional patient will not have good growth after such a transplant. Most transplant surgeons still utilize this technique, although they may call it by a different name. It is a much quicker and simpler procedure from the transplant surgeon’s perspective.
Fortunately, more and more hair transplant clinics are beginning to convert to the follicular unit transplantation method exclusively. This may, in part, be due to better educated patients. There is no question that it is a long, tedious, and labor intensive procedure, but the results are so good that once the surgeon has made the difficult transition from mini and micrografts to follicular units, he will not go back. It is only common sense to move the hair in the same units as it started. And it only makes sense to microscopically enhance the dissection process to make sure that it is done with minimal damage to the roots.
With follicular unit transplantation, the single hair units are sprinkled in the front of the hairline followed successively by the 2, 3, and possibly 4 hair units. This recreates the natural density gradient found in balding men without creating “plugginess”. Additionally, using this technique, it is extremely rare for the patient to experience anything but great growth. When patients are adequately educated, it is difficult for them to ever consider mini and micrografts again. It is also telling that the vast majority of transplant surgeons who now have transplants done on themselves have it done with follicular units. No matter how the hair is combed, styled, or cut, and no matter from what angle it is viewed, even if it is wet or windy, there should not be a “pluggy” appearance. It is hard to imagine someone settling for anything less.
Several arguments have been brought to bear on follicular units by surgeons not performing them. One is the claim that minigrafts give more density. The fallacy of this argument can be approached from two directions. First, if they believe that minigrafts give more density than follicular units simply because each graft has more hair, then why are they not utilizing the old-fashioned 4 mm plugs? These 4 mm plugs could have 20 to 25 hairs in a single graft as opposed to the 3 to 10 hairs in a minigraft. It is because they know that if they transplant 3 or 4 minigrafts, they are actually transplanting the same amount of hair as a single 4 mm plug, but with less “plugginess”. The logic of using 2 or 3 follicular units instead of a single minigraft is no different.
Second, if a strip of hair was removed from a scalp and half of it was dissected into minigrafts and half was dissected
into follicular units, the same amount of hair would be removed and dissected with each method. The only difference (excluding the fact that the minigrafts were not dissected with a microscope) would be the size of the grafts and thus the potential for “plugginess”. The same number of hairs would be transplanted either way.
The only instance their argument has any merit is if only a small area is being transplanted. If the same number of minigrafts and follicular units were transplanted into a small area side by side, the minigrafts side would likely grow with more density (in addition to more “plugginess”). But if the patient is only interested in density or if the caliber of his hair is very fine, there is nothing in the follicular unit “rule book” that says that follicular units must be cut as single units. It is even easier for the technicians to dissect them into 2 or 3 follicular unit grafts rather than single follicular units. That produces the same size graft as the minigraft without the potential disruption of the individual follicular units.
The other common argument made against follicular units is that the great number of follicular units implanted in large cases may overwhelm the scalp’s ability to heal and result in poor growth. The scalp is an extremely vascular area as we all know after watching scalp wounds bleed. It is more than capable of accepting large numbers of transplanted grafts in a single setting. Follicular units are planted in holes made with needles smaller than needles used to draw blood with. Thus, there appears to be less damage to the scalp compared with the damage caused by the holes formed for the minigrafts.
When larger grafts are transplanted, it is not unusual to find a doughnut-pattern of growth where the central hairs have died because they were not adequately oxygenated by the surrounding tissue. Common sense dictates that the smaller the size of the graft, the less of a problem this would be. I have never seen a scalp’s ability to heal be overwhelmed by a large session of follicular units. I always hesitate when I use the word “never”. I am sure it could happen with poor technique, poor judgment, or with scalps with significant scar tissue. But it has not been my experience.
Another advantage to follicular unit transplantation is that noticeable scarring in the recipient area is extremely rare. The smaller recipient sites made with needles for follicular units are much less likely to show visible scarring when compared to the sites made with punches and scalpel blades for minigrafts. There are frequent problems known as “cobblestoning” and “dimpling” associated with minigrafts. As the names imply, “cobblestoning” is scar formation protruding above the skin and “dimpling” is the reverse. The shadowing created by these scars can be very difficult, if not impossible, to hide. The only way to correct it is to keep adding grafts around the scars in subsequent sessions.
The risk of “plugginess” with minigrafts cannot be over emphasized. It is very common for men to get locked into a slow cycle of repeat procedures to try and hide the resultant “plugginess” of previous procedures. This may continue until the patient runs out of donor hair. On the other hand, repeat procedures are not necessary to hide “plugginess” with follicular units since there should be none evident.
Content Provided By Blaine Lehr, MD
The Dermatology Clinic Inc.
IAHRS Recommended Hair Transplant Surgeon