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Does the recipient site influence the hair growth characteristics in hair transplantation? It is widely known that hair transplantation can be carried out in patients who are tending towards baldness or have become bald. Hair transplantation techniques have now extended to correcting hair loss in various parts of the body including eyebrows, eyelashes and pubic area. One of the basic questions that arise out of such scalp to non scalp area is the behavior of these hair transplants. Can the hair that grows on the head, when transplanted to other parts of the body maintain its growth characteristics? To explain this, Hwang and colleagues from the Departments of Dermatology and Immunology, Kyungpook National University School of Medicine, Korea have conducted a couple of experiments to substantiate their findings. In their first experiment, they transplanted hair from the back of the head to the lower part of the leg. This was monitored constantly for parameters such as number of surviving or growing hairs, size of the shaft and the thickness of the hair and its growth in length, in a time period ranging from 6 months to 3 years. The second experiment was to transplant the already transplanted and established hair in the lower leg, back to the head. In order to identify the areas from which the transplant was conducted, the hair from the lower leg was placed in the nape of the left side of neck while hair from back of the head were transplanted in the right nape. This was followed to evaluate the growth patterns of both these transplants and if any significant difference was visible. As the third experiment, a group of patients with male pattern baldness were studied for growth patterns of hair when transplanted from the back of the head to the area in the front of the head. Dr. Norman Orentriech in 1959 put forth a theory called ‘donor dominance’. This central dogma of hair transplantation procedure is that a hair follicle can grow in any part of the body just as it grows in its donor site. With this concept in mind, most of the hair transplant procedures have taken shape. However, there has been no concrete evidence to prove that the transplanted hair indeed behaves that way. The above set of experiments has challenged this claim. Let us examine the results of the above experiments and what they reveal about hair growth patterns. The study involved basic statistical methods to compare the results. In the first experiment, the number of surviving transplanted hairs was about 60% of the total transplanted hairs. When compared with the hair from the back of the head, it was seen that the transplanted hairs on the lower leg grew rather slow although the size of the hair shaft has no significant difference. In the second experiment, there was no difference in the shaft size, growth rate and survival rates of the transplanted hairs, both in the already established lower leg hairs and the control set from the back of the head. But when this was compared with the natural hair of the back of the head, it was seen that the growth rate was comparatively low. To confirm if the 1st and 2nd experimental results weren’t due to follicular damage during transplantation, regular patients treated for hair loss via hair transplantation were evaluated. Hairs of patients who had donor hairs from the back of the head transplanted to the front showed absolutely no difference in growth pattern and size of the hair shaft. What can be concluded from these experiments is that the transplanted hairs do not behave the same way as in their site of origin. An important point to be noted is that, the transplanted hairs did not show any reduction in their shaft size. Hence other factors such as the blood supply in that area, fat tissues, the architecture of the skin layers etc. probably have a role to play in the growth pattern of the hair. There can be no other explanation when comparing the percentage of surviving hairs; 92% survival in hair transplants on the head and 60% survival in other parts of the body. But when re-transplanted on the head, the survival rates shot up to 95 % [lower leg hair] and 92% [control from the back of the head]. So this study confirms that the part of the body where the hair is transplanted governs its growth and the pattern can definitely differ and not remain the same.
Does the recipient site influence the hair growth characteristics in hair transplantation references
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