FUE Transection and Hair Transplants

FUE Transection
Dr. Alan Feller

There are two distinct types of transection inherent to FUE. The first is the application of a punch “off angle” to the target FU. This will result in a slanted slice right through part or the whole of the FU. The other type of transection is not so obvious.

During my first FUEs I noticed that I was getting a large number of successful deliveries, but under the microscope I noted that many of these grafts had partially transected bulbs in the lateral aspects. That is, in a three haired FU, I would successfully extract the FU, but only the center graft was intact. At first I though it was the result of poor angulation, but upon close insepction I realized this was not possible. While an “off angle” attempt may result in the transection of one side of a (planar) 3 haired graft, it didn’t explain why the other side was also cut.

If the geometry of the scenerio is considered schematically, logic demands that the opposite side follicle not only be untouched, but given an extra bit of room of safety directly proportinal to that of the transected side. In other words, only one side can be transected, not both, but this was not the case. Both sides were consistently transected.Furthermore, it happened often enough for me to realize that I couldn’t just by mere chance be shaving the graft so close as to injure the follicle but not the nearby dermis, time and time again. No, something else had to be happening. Then it became clear.

Torsional or linear tearing was probably the root cause of this root problem. As the punch travels down the dermis there is a frictional componenet created by the wall of the punch, both static and dynamic. To decrease the linear friction, which is easily detected by even an amateurs hand, we tend to rotate the punch so that it will procede faster and easier through the skin. However, this now introduces a torsional component, that combined with friction creates a shearing force that I suspect rips the lateral and poorly supported deep follicles and bulbs off the body of the graft. This explains why both sides would suffer “transection” but not the center.

This torsional phenomena probably occurred with the larger punch grafting, but was ignored due to the relatively small amount of damaged lateral follicles compared to the safe and intact core follicles.

To reduce the amount of torsional transection, it is helpful to reduce the spinning of the punch to more of a recipricating action. Even better is to use a punch whose walls are slightly greater in diameter to the cutting edge. This will decrease friction and “grab” of the graft during extraction.

It is also helpful to punch down to a slightly more shallow depth during the scoring process and rely more on the perforation technique to release the graft for delivery. This is accomplished with practice.