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.

Figure 5-1. Individual components making up a follicular unit.

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.

Figure 5-2, A) Mini and micrograft preparation is performed without microscopes leading to frequent disruption of follicular units. B) Follicular units preparation is performed microscopically so that the follicular unit remains intact.

Figure 5-3, The same number and size of lines are present in “A” and “B”. A) 6 lines together representing the hairs in a minigraft. B) 2 lines together representing the hairs in a follicular unit. “A” is much more “pluggy” than “B”.