Follicle Unit Transplant or Strip Surgery (FUT/S) Technique
FUT Strip surgery is the more traditional method for harvesting follicular units from the Safe Donor Area at the back and sides of the scalp. With this technique, an elliptical strip of tissue is removed from the scalp using a scalpel blade. The width of the “strip” depends on how many follicle units are required for harvesting to yield the number required for doing the hair restoration procedure as discussed and agreed with the patient. However, the “strip” width is usually between 0.8mm to 1.2mm wide and between 20cm to 26cm in length. This mostly provides the number of follicle units required.
It is important not to take a FUT strip that has a width that creates excessive wound tension on closing. The degree of wound tension will determine, to a large degree, if the scar heals as a thin line or makes a wider scar. More tension on the wound tends to create wider scars and, therefore, we take several steps to prevent wide scars from forming. Firstly, we eliminate wound tension by having the patient do scalp laxity exercises for 4 to 6 weeks prior to their surgery date; this improves scalp laxity and enables tension free closure. It is also important not to take too wide a “strip” at the time of harvesting; I make use of the tried and tested Mayer-Pauls wound tension scale to determine how wide a strip we can take. Furthermore, we also make use of HRH (Human Recombinant Hyaluronidase) which, when injected along the wound margin, breaks down collagen cross linking temporarily and allows an additional 20% and more laxity on closure, providing an additional method for relieving wound tension. I also use a continuous subcutaneous layer of dissolvable suture material to further alleviate skin tension on wound closure when approximating the cutaneous layer.
Lastly, I always know that I don’t have to stretch the limits of the FUT strip harvest, because the balance of the follicle units, which may not be harvested via FUT strip harvest, can be harvested via the FUE technique.
My staff use Stereomicroscope magnification on transparent graft boards (with back, frontal and intra graft board illumination) to sliver and dissect the follicular unit grafts from the harvested FUT strip tissue.
The whole procedure of FUT Strip harvesting is done once the scalp has been completely anaesthetised using a blunt subcutaneous cannula to administer the local anaesthetic in a relatively pain free manner.
Follicle Unit Extraction (FUE) Technique
FUE harvesting technique (the more modern technique) is where each follicular unit is harvested one-by-one from the Safe Donor Area, after local anaesthetic has been administered via using a blunt cannula in a relatively pain free manner. With FUE technique, the donor hair is shaved to a length of between 0.8mm to 1.0mm prior to harvesting. I then use a sharp surrounded 0.9mm Cole Punch to first cut through the Arrector pili muscle of each follicle that I select for harvesting. This circumferential incision is approximately 1.6mm to 2.0mm deep, and it is done with either a Manual FUE Punch or a Powered FUE Punch, depending on the specific scalp characteristics and the requirements. Once the circumferential incision is done, the follicular unit graft is carefully removed, using forceps in a three step method. My technical staff may then trim these FUE grafts slightly under Stereomicroscopic magnification.
The above description is the basic difference in harvesting methodology between FUT strip harvesting and FUE harvesting. I perform both harvesting techniques regularly and don’t regard one method as a better or worse method than the other. I often combine both methods when the situation calls for it. Both methods have a solid standing in hair restoration and each individual patient’s case dictates which method should be favoured or whether the two techniques should be used in combination. This choice and ultimate decision is mostly determined by patient preference combined with donor area characteristics.
FUT Technique and Trichophytic Closure
When Follicular Unit Transplantation (FUT) is performed, the procedure leaves a linear scar in the area where the surgeon removed the strip of tissue.
I make use of the Trichophytic technique when closing my FUT strip wounds. I bevel the lower edge or the upper edge of the wound at a 45 degree angle, which allows hair to grow through the healing wound, providing camouflage (which partially hides the scar), making it difficult to ascertain that a FUT strip surgery was performed in the Safe Donor Area.
This technique provides a better cosmetic outcome for patients, especially when they choose to cut their hair short after the procedure.
Trichophytic closure technique is also used on patients who have had previous FUT Strip surgery. In such cases, I excise the “old scar” at the time of harvesting the “new strip” in order to leave the donor area as unmarked as possible, by camouflaging the existing donor scar with hair growing through the scar.