Follicular Unit Extraction
Follicular Unit Extraction (FUE) is a method of obtaining donor hair for Follicular Unit Transplantation (FUT), where individual follicular units are harvested directly from the donor area, without the need for a linear incision. In this hair restoration procedure, a 1-mm punch is used to make a small circular incision in the skin around the upper part of the follicular unit, which is then extracted directly from the scalp.
Follicular Unit Transplantation and Follicular Unit Extraction are sometimes viewed as being two totally different procedures. FUE, in fact, is a type FUT where the follicular units are extracted directly from the scalp, rather than being microscopically dissected from a strip that has already been removed. To say it another way, in Follicular Unit Transplantation, individual follicular units can be obtained in one of two ways; either through single strip harvesting and stereomicroscopic dissection, or through FUE.
Therefore, when comparisons are made between FUT and FUE, what is really being compared is the way the follicular grafts are obtained (i.e. strip harvesting and dissection vs. direct extraction). The harvesting method does have other implications for the procedure such as the transection (damage) rate, distribution of follicular units, number of grafts per session, post-op care and the total yield.
Because FUE does not leave a linear scar, it is used for patients who want to wear their hair very short. The procedure is also useful for those who have healed poorly from traditional strip harvesting or who have a very tight scalp. Possibly the most important application of this technique is to camouflage a widened linear donor scar from a prior hair transplant procedure.
Patients differ significantly with respect to the ease in which the units can be removed from the scalp, with extraction in some patients producing unacceptable levels of transaction (damage due to cut hair follicles). All patients considering FUE should be tested for the ease of extraction (the FOX Test) so that those in whom extraction is difficult, or who show significant degrees of transaction, can be identified in advance.
Patients undergoing a full Follicular Unit Transplantation procedure should also be tested for Follicular Unit Extraction at the time of surgery, in the event FUE may be needed in a future session. One such use might be the camouflage of the linear scar after the patient’s final FUT procedure. This testing is done routinely (at no charge) in our practice.
A significant advance in Follicular Unit Extraction has been the addition of “blunt” dissection to the original technique of “sharp” dissection followed by extraction. In this three-step technique, a sharp punch is used to score the epidermis (cut just the upper part of the skin) and then a dull punch is used to bluntly dissect (separate) the follicular unit grafts from the surrounding deeper dermis. The third step is the same, namely removing the follicular graft from the scalp using fine forceps.
The advantage of this hair transplant technique over the original two-step process is that using a dull punch minimizes follicle transection (damage). As the blunt-tipped punch is advanced into the dermis, the follicles, which naturally separate deeper in the skin, are “gathered together” within the opening of the instrument, rather than risk the lower portions of the follicles being cut off. Another significant advantage of the new technique is that it increases the number of patients who are FOX positive and thus who are able to benefit from FUE.
A problem of the three-step technique, however, is a higher incidence of buried grafts. When a buried graft is identified, it can sometimes be extracted by applying pressure to the surrounding skin. If this maneuver fails, a small incision is made to enlarge the opening and facilitate the removal of the graft. If not removed, a buried graft can occasionally result in a small cyst that would need to be removed at a later date.
Another problem is that during the extraction attempt the epidermis and upper dermis may separate from the rest of the follicle. This phenomenon has been called “capping.” When this occurs, the lower portion of the graft can sometimes be grabbed and extracted. When this is not possible, the lower potion is simply left behind. In this case the wound will heal and the lower portion of the follicle should produce a new hair.
The Advantages and Disadvantages of Follicular Unit Extraction
FUE’s main limitation, when compared to FUT, is that it is less efficient in harvesting hair from the mid-portion of the permanent zone. In FUT, the strip is taken from the optimal (central) part of the donor region so all the hair in this area can be removed and transplanted. After the strip is removed, the wound edges are sewn together.
In FUE, hair is extracted, but the intervening bald skin between the follicular units is not removed. Therefore, the surgeon must leave enough hair in the area to cover the remaining donor scalp. Consequently, there is considerably less total donor hair available, perhaps half as much as with FUT. This represents a significant disadvantage, since a limited donor supply is the main factor that prevents a complete hair restoration in many patients. To compensate for the inability to harvest all the hair from the permanent zone, the surgeon may eventually be tempted to harvest hair from the upper and lower margins of the original donor area and risk the hair being of poor quality or being non-permanent.
In Follicular Unit Extraction the wounds, although small, are left open to heal, leaving hundreds to thousands of tiny scars. Although not readily apparent, this scarring distorts adjacent follicular units and makes subsequent sessions more difficult. This is an additional factor that limits the total available donor supply in FUE.
Although three-step FUE significantly decreases the amount of transection and damage during the extraction, the inability to fully access the mid-portion of the permanent zone, significantly limits the total amount of hair that can be accessed through FUE, rendering it a far less robust procedure than FUT for moderate to advanced balding.
The table below summarizes the pros and cons of Follicular Unit Extraction.
- No linear scar
- Important for those who wear their hair short
- Decreases healing time in the donor area
- Useful for those with a greater risk of donor scarring (Asians)
- Ideal for repairing donor scars that cannot be excised
- No limitations on strenuous exercise after the procedure
- Less post-op discomfort
- Provides an alternative when the scalp is too tight for a strip excision
- Extends the size of the donor area (but not necessarily the total number of grafts)
- Enables one to harvest finer hair from the nape of the neck to be used at the hairline or for eyebrows
- Makes it theoretically possible to harvest non-scalp hair
- ex. beard or body hair
- Most useful when a limited number of grafts are needed
- Maximum follicular unit graft yield is lower than with FUT
- Due to the inability to harvest all the hair from the mid-permanent zone
- The scarring and distortion of the donor scalp from FUE makes subsequent FUE sessions more difficult
- Greater follicular transection (damage) compared to FUT
- Greater patient variability in who are good candidates compared to FUT
- More difficult to capture the entire follicular unit
- More difficult to obtain a natural distribution of follicular units
- For efficiency, the largest follicular units are targeted, but these may not be ideal for the hairline
- Grafts are more fragile and subject to trauma during placing
- Since they often lack the protective dermis and fat of microscopically dissected grafts
- Microscopic dissection may still be needed
- If the number of single-hair grafts is inadequate
- To remove hair fragments
- Grafts harvested from outside the donor area will not be permanent
- After large numbers of graft are harvested, fine stippled scars may become visible due to thinning of donor area
- Size of session is limited
- Requires multiple sessions to equal the size of a single FUT
- Takes longer to perform
More expensive than FUT
- Problems of “capping”
This occurs when the top of the graft pulls off during extraction
- Problems of buried grafts
- This occurs during the blunt phase of the three-step technique when the graft is pushed into to fat and must be removed through a small incision or risked producing a cyst