Two essential groups of problems arise when dealing with crown balding. The artistic/aesthetic difficulties crop up when transplanting an area characterized by a swirling vortex of hair directions, often with thinner hair toward the middle. Also, this configuration amounts to a circular "part" which exposes the scalp, and any transplanted groups, to fairly close examination in social settings. Therefore, it is a technically challenging area in which to create appropriately placed and oriented recipient sites; and the correct size grafts must be placed in different regions of the crown.

The other major difficulties are related to supply and demand. The potential size alone of the crown can create an insatiable demand for donor hair, which, as we have seen, is limited. Let's consider the mathematics of this and other regions: the frontal area, from the hairline back to a line drawn across between the two temporal angles, measures an area of roughly 50 cm 2 . The top of the head, from behind the frontal area to the front border of the crown, may be about 150 cm 2 . The crown, as we pointed out can vary widely in size, but in a Class VI or VII patient can be as large as 175 cm 2 : a lot of area to cover! Doing the calculations, we see that, even if we transplant a minimal density (say, 15 FU's or about 35 hairs per cm 2 ) to a fully bald crown (about 175 cm 2 ), we have used roughly 2600 follicular unit grafts. If we go for a higher density, for example, 40 FU, then we have used 7000 grafts, more than the average person even has available in their donor area. Again, this is in the crown alone. This leaves the cosmetically important frontal area and hairline with essentially no donor hair for transplantation.

While the above example is an extreme one, it is used as an example to show just how much of the donor reserves can be exhausted by the injudicious attempt to fully restore the crown with high density. In a young, desperate man with new onset crown balding, it may be tempting to try to fill this area in with dense packing of grafts; this, however, could be to his long-term detriment. If the balding in the crown continues to expand, the patient and surgeon can find themselves "chasing" the balding with ever increasing circles of grafts, like the layers of an onion. Not only can this quickly deplete the donor area, but if the hair characteristics and donor density are unfavorable, he may find himself with an "island" of dense crown hair sitting amidst an ocean of bald scalp. Moreover, what is he to do if frontal balding ensues? The man who was desperate about his crown balding at age 24, is bound to be absolutely frantic when his hairline starts to recede at 28; this will be even more noticeable than the hair loss at the crown.

Often, especially in younger men, it is appropriate to use medical management with Propecia and/or Rogaine, which tend to be more effective in the crown area than frontally. This may help at least maintain the hair in the region; surgical planning can be done to include hairline restoration, and transplantation to the frontal area as far back as the crown. This will be a more beneficial use of donor reserves from a cosmetic standpoint. The crown can then be transplanted carefully and judiciously, perhaps with a lower density, and the advancement of the patient's hair loss can be observed over time. We must always be mindful that the large crown can drain the donor reserves, and that transplanted density is often best "spent" on the top, in the frontal area, and at the hairline.