One of the most important aspects of Follicular Unit Hair Transplantation is stereo-microscopic dissection. This allows follicular units to be removed from the donor strip without being broken up or damaged. During the dissection, it is critical that the whole follicular unit is kept intact as this will maximize its growth. Intact follicular units will also give the most fullness to the hair restoration, as they contain the full, natural complement of 1-4 hairs.
The average donor strip (above left) is approximately 1cm wide and of variable length, depending upon the number of follicular units that are needed for the hair restoration. In the average person’s scalp, there are approximately 90-100 follicular units per square cm of donor tissue, so a 2,000 graft hair transplant session would require a 1cm wide strip that is slightly over 20 cm in length.
The series of stereo-microscopes (above right) needed for the follicular unit dissection are located in the patient’s surgical room, so that graft dissection can occur simultaneously with other steps of the hair restoration and so that the hair transplantation can proceed seamlessly.
The first step in stereo-microscopic dissection is a process called “slivering” (above left). In slivering, the dissector divides the long donor strip into smaller sections of approximately 2-2.5mm in width. The sectioning is accomplished by passing a scalpel blade through the spaces around follicular units, rather than merely cutting directly through the block of tissue. This technique generates smaller pieces of hair bearing tissue without breaking up follicular units and without transecting (cutting) hair follicles.
The dissector then isolates the individual follicular units from these small sections by trimming away excess dermis and fat. (Above right).
The photo (above left) shows 1-, 2-, 3-, and 4-hair follicular units. Hundreds of these individual units are sorted according to the numbers of hairs they contain. They are then stored in Ringer’s lactate solution and refrigerated while waiting placement into the scalp (above right). The Ringer’s lactate is used because it closely mimics blood plasma and is more physiologic than the more commonly used saline solution. The refrigeration, at 40 degrees Fahrenheit, slows down the metabolism of the grafts and increases the time they can be stored outside the body.
Once the recipient sites have been created, a portion of the grafts are removed from the refrigerated storage and placed into Petri-dishes that sit on a wall-mounted placing stand at the head of the operating table (above left). The grafts are bathed in the same Ringer’s lactate (above right), but the temperature is now held at 59 degrees Fahrenheit while they await placement into the patient’s scalp.