Editorial Commentary by Robert M. Bernstein, New York, NY
Dermatol Surgery 1998; 24(12):1342-1346.
New Models, Methods, and Possibilities
The “modern era” of surgical hair restoration, involving the movement of large numbers of very small grafts, has given the hair transplant surgeon the ability to produce remarkably natural results in just a few sessions. Although the new hair restoration procedures have many advantages, they also pose new problems. Among them are the increased fragility of the smaller grafts, the labor-intensive nature of the hair transplant procedure, and the extended operating time.
There has been a significant amount of progress made in addressing these special problems. Stereo-microscopic dissection has allowed the meticulous isolation of individual follicular units. Back-light tables have been designed to facilitate the generation of micrografts in patients with blond or gray hair. Special forceps are available which prevent crush injury while handling small grafts during the hair transplant. Automation of recipient site creation and placing has decreased injury during graft insertion by reducing desiccation and mechanical trauma.
The increased time that grafts are outside the body while awaiting placement becomes more problematic in the longer procedures. Dr. Limmer has shown that the survival of micrografts refrigerated at 4OC decreases over time, with the most significant changes occurring after 24 hours. Methods used to shorten the time grafts are outside the body include dividing a larger hair transplant procedure into half and performing it over two days, taking out the donor strip in multiple small sections during the course of the hair restoration surgery, employing a larger staff to speed up the procedure, and combining site creation and graft insertion through automation. Some have tried to hasten the process by rapidly cutting mini-micrografts “to size” on mechanized cutting surfaces, however, this sacrifices quality. Regardless of these methods, the transplantation of large numbers of small grafts inevitably results in the grafts being deprived of their normal oxygen supply for a significant period of time.
If cooling has been the technique most commonly used to slow the metabolic activity of grafts in their hypoxic external environment, the author’s idea of enhancing their survival during a hair transplant with triphosphate-magnesium chloride and deferoxamine mesylate is certainly the most creative. In the past, different physiologic holding solutions have been experimented with in the hope of stabilizing the intra- and extra-cellular solute concentrations of small grafts, but none have attempted to specifically enhance their metabolism. The authors have adapted techniques used in other organ systems with a “one-two punch” in combating potential damage from oxygen deprivation. Exogenous ATP is used to partially replenish the depleted stores resulting from decreased mitochondrial production and then deferoxamine is used to soak up the cytotoxic oxygen free radicals that invariably sneak by. How clever!
In the study under discussion, the authors showed enhanced survival and growth rates of follicles during a hair transplant when the experimental storage medium was compared to a control using isotonic saline at room temperature. Since hair transplant surgeons almost invariably store grafts in chilled solutions, it would be important to use grafts that have been refrigerated in either physiologic saline or Ringer’s lactate to serve as the control. It would also be important to see if the new storage medium’s “boosters” and “scavengers” can function in a cool environment, when the entire metabolic activity of the system is slowed down. With these further experiments, the practical benefits of the new storage medium for surgical hair restoration might be better evaluated.
The major contribution of this study may not be in the new holding solution it tests, but rather in the methodology that is used. The author’s in-vitro model to measure graft survival circumvents many of the problems that have hindered evaluating hair growth studies in the past, namely difficulty in finding patients with totally bald areas of scalp that are willing to be involved in a six month experiment, and counting and/or measuring hairs in vivo. With this in-vitro model, hair growth can be scientifically monitored and results may be assessed in a relatively short period of time.
There are many potential culprits during the hair transplant contributing to the poor growth of small grafts that have yet to be objectively evaluated. The author’s model for measuring graft growth might be applied to each of them. In these areas may lay the studies greatest value.