Careful dissection of hair follicular implants is crucial for the success of surgery

Hair restoration procedure Isolating the hair transplant grafts ready for implantation

Isolating the Hair Transplant Grafts ready for Implantation

After the hair transplant donor site has been planned and the donor skin excised, the donor skin strip must be dissected and processed to make grafts ready for implantation.

Size of donor area and tissue to be collected

The donor strip of skin is taken to a preparation room. Here the skin is dissected into grafts ready for implantation. In modern clinics the donor skin is dissected by a team of highly trained assistants. There can be three to five, and sometimes even seven or eight, technicians dissecting the skin simultaneously. Arguably the best, hair transplant clinics have their technicians divide up the donor skin using stereo dissecting microscopes.

Using the binocular microscope, the assistants subdivide the single strip into thin slivers 2 to 3 follicular units wide. These individual slivers are then further dissected into individual follicular units. The tissue is handled with fine forceps and cut with small scalpels. The tissue is held with forceps on one side, the scalpel is angled parallel to the angle of the hair follicles, and the skin is cut to the side of a follicular unit. If the technicians see significantly damaged hair follicles or hair follicle missing a bulb, they will cut these away from the follicular units and discard them. They cut off much of the non hair bearing scalp skin around the hair follicles. The smaller the follicular unit the quicker and better it will heal into the skin once it is implanted. It is also less likely to leave a visible scar. The grafts, separated by numbers of hairs, are kept in chilled saline until the time of implantation, separated by hair number. The mean number of hairs per graft is 2.2 to 2.3, so most grafts contain 2 or 3 hairs. Follicular units of ones and twos will be used towards the front to make the hair line, while follicular units of three and four hair follicles will be used to fill in behind the implanted hair line.

The use of dissecting stereo microscopes during hair transplant graft dissection has only recently been advocated as a means of reducing hair follicle damage and improving graft growth. The first publication on their use was in 1994 although the top hair transplant doctors were using microscopes for dissection since about 1990. If a dissecting microscope is not used to cut up the donor skin strip, it has been found that it is much more likely that hair follicles will be cut and damaged. Using the microscope, technicians can see the hair follicles much better and so are less likely to cut through a hair follicle. One study evaluated the prevalence of hair follicle transection in grafts prepared with and without the dissecting stereomicroscope. Half as much transection (10% vs 20%) was noted in grafts prepared with microscopes, suggesting their use may be associated with less hair follicle trauma and improved hair growth (Cooley 1999).

To be fair to those surgeons that do not have their technicians use microscopes when they cut up the donor skin into grafts, some studies have shown that implanted hair follicles can grow even after sustaining mild to moderate damage and that sometimes cutting the hair follicles in two can actually lead to two hair follicles being produced from one! The issue is how much damage a hair follicle can sustain before it becomes so damaged that it cannot grow. Those follicles from which more than a third of the lower follicle and bulb region have been cut will not grow. In light of this, dissecting hair follicles under a microscope is probably the safest way to ensure that the dissected hair follicles are healthy and will survive and grow after implantation. One study that compared implanted hair follicles that had been dissected with microscopes or loupes suggested microscope use increased the hair yield by as much as 20% (Berstein 1998).

Dissecting the hair follicles under a microscope also enables a relatively new development in hair restoration to take place – follicular unit grafting. Hair follicles often grow in natural clusters of twos, threes, and fours. Using the stereo dissecting microscope, the hair follicles in the donor skin can be divided into their natural “follicular units” and implanted in these units. This makes for a much more natural looking transplant result. So in short, microscopic dissection results in grafts that are smaller and contain a minimum amount of scalp skin. These grafts can be placed into smaller recipient sites, and this theoretically allows for a greater hair density, faster healing, and less trauma to any existing hairs in the implant recipient area. In addition, transplanting grafts with a limited amount of skin around them minimizes any changes in pigmentation and texture of the recipient scalp skin. So with the donor skin now dissected into follicular units the next part of the procedure, the implantation, can begin.