| The evolution of FUT and mass marketing in
medicine has led most physicians to quote costs for hair transplanting as being
determined, at least partially, by the number of grafts transplanted. In
addition, patients are better informed about the procedure via advertisements
and the web. These sources may or may not be misleading and intelligent
individuals will arrive at the consultation with specific questions and often
some level of skepticism. The result of the foregoing is that one of the most
common questions asked, is "How many grafts do I need to have transplanted?"
This of course is one of the most important questions a hair restoration
surgeon needs to answer for himself in order to be able to estimate how much
donor tissue he has to excise to create the desired effect. Unfortunately, this
number is dependent on numerous factors that will include the patient’s
objectives, hair/skin color contrast, hair caliber, wave, curl, etc. – and the
types of grafts the physician intends to use. In an attempt to come to some type
of concrete and consistent way of making this estimate, a number of operators
have arrived at different techniques for estimating a) the size of the recipient
area and b) at least the number of FU they must harvest to treat that area; they
are described below.
As a by-product of that estimate physicians also then have a way of conveying
the likely cost of the treatments and the coverage that number of FU will
produce. It is important to emphasize again, however, that even very careful
estimations of the number of FU required, are subject to the aforementioned
variables, as well as to changes in the patient’s density or coverage objectives
as a number of sessions are carried out. Thus, calculations for the above-noted
purposes should always be clearly conveyed to the patient as only
"estimates".
The less scientific "estimates" of the size of the recipient area and the
number of FU necessary to produce a desired effect in that area as described
below by Bessam Farjo and Steven Chang, are useful for conveying general
concepts to patients and physicians and they are easy to carry out, making them
more practical for most practitioners than Cole’s method which has just been
described. There is, of course, another purpose to most accurately estimating
the number of FU a given size of donor tissue contains; it provides a mechanism
for calculating the skill of you and your technicians in producing the hoped for
100% yield of FU from that strip – both before preparation and insertion of the
FU and after the FU have been given the opportunity to regrow in the recipient
area. In other words, a very accurate estimate of the number of FU in the donor
strip is the best way of furthering the scientific basis of hair restoration
surgery. Cole’s method is a better one for this purpose than either Farjo’s or
Chang’s. Once again, in hair transplanting, different techniques have different
strengths and weaknesses.
It is also worthwhile keeping in mind that although it is widely believed
that the density of scalp FU is a consistent 1 FU/mm2, this is not
true according to Cole’s studies.14, FU density in the mastoid and
temporal regions is often less than the 1 FU/mm2 which is often found
in the vertex and mid-occipital regions.14 Thus, what is required in
some areas to produce an appearance of "normal" density may be greater or less
than the often quoted "50% of original density" or 50% of 1 FU/mm2.
In addition, depending on hair characteristics, 50% of original density may or
may not be necessary to create this effect.
The Chang Method:Chang begins his method of estimating the number of
grafts necessary to treat a recipient area by marking the proposed recipient
area on the scalp of his patient with a "china marker". He then applies a
transparent sheet (plastic food-wrap) over the scalp and traces the area to be
covered on the transparent sheet. (Interestingly, three years earlier, Cole
described assessment of the recipient area for purposes of donor area assessment
by tracing its outline on a transparent sheet. This transparent sheet is then
placed over a specially designed graphic paper that has been divided into large
and small squares (Fig. #). Each small square is 1 cm2 and each large
square is 4 cm2. By doing this one can estimate the approximate
recipient area size in square cm. A digital photograph of the scalp with the
recipient area marked in by china marker is taken and kept on file in the
patient’s chart as is the photocopy of the transparent sheet. A copy of the
graphic paper that Chang uses can be downloaded from the website:
http://www.hairtransplant.com/Spencer.pbf. Chang states that 90% of his patients
are satisfied with 50% of the donor site density, although he also notes that
this, of course, depends on the patient’s hair color/texture, skin color,
contrast between skin and hair color and the patient’s age. However, for the
average patient, they attempt to reproduce the 50% density in two sessions. In
an alopecic patient, for example, they attempt to create this 50% density in two
sessions of 25% density each. Thus, if the bald area is 100 cm2 they
must harvest 25 cm2 of donor area in each session in order to produce
25% of the donor area hair. The number of grafts that can be obtained from this
amount of donor tissue is easily calculated. Based on the assumption that there
is one FU per mm2 (as noted earlier, this is not an entirely
accurate) 1 cm2 can therefore be expected to produce 100 grafts and
25 cm2 2500 grafts. Chang is careful to not tell patients how many
grafts are contained in 1 cm2 of their donor strip. They are told
only that he will deliver 25% of their own density per session. Using the
previously noted example, in order to cover 100 cm2 of alopecia he
harvests 25 cm2 of donor tissue. This should produce 25% density and
there is no need to count how many hairs are present in the donor strip in order
to reach 25% of the donor strip density. The advantages of this approach are
listed in an article published in Hair Transplant Forum in July/August
2001 (Chang, Stephen, estimate number of grafts and donor area, Hair
Transplant Forum International 2001, Vol. 11 No. 4, pgs. 97-102).
The Farjo Method:Bessam Farjo has described a different method of
estimating the size of the recipient area and therefore the number of FU
necessary to treat it. (Farjo, Bessam, estimating graft numbers made easy for
the recipient site, Hair Transplant Forum International 2001, Vol. 11,
No. 4, pg. 101). His method is based on conceptualizing the recipient area into
simple geometric shapes, essentially triangles, rectangles, squares, or circles.
For example, the frontal forelock shown in Fig.#4a can be conceptualized as a
triangle. As shown in Fig. #b4b, the area of the double-line triangle will
provide a good estimation of the area of the forelock. The area of the triangle
= A x B, where A is the distance between the anterior and most-posterior point
of the base of the triangle in the mid-line (not the base of the
forelock) and B is equal to half of the base of the triangle. For example, if
A=10 cm and B= 5 cm, then the area of the triangle and the isolated frontal
forelock would be 10 x 5 = 50 cm2. Cole first described the
triangular method of assessing the surface area of the recipient area using
triangles in 1998, at the Orlando Live Surgery workshop. For transplanting a
moustache.* with moustache hair restoration at the 1999 Orlando live surgery
workshop. When dealing with the vertex area the shape is conceptualized as being
a circle (Fig. #6) and the area is equal to radius 2 x Pi. For
example, if the diameter of the circle is 10 cm then the area = 5 x 5 x 3.14 =
78.5 cm2. In estimating a total recipient area, which includes both
the frontal mid-scalp and crown area, Farjo accepts Cole’s suggestion to
conceptualize the recipient area as a long oval (Fig. #5). The surface area of a
long oval is equal to (A/2) x (B/2) x Pi.17 If only half of the
recipient area is to be treated, for example, either the anterior or posterior
half, then the total area is simply divided by 2.
It is worthwhile repeating that Cole’s method of estimating the number of FU
contained in a donor strip is far more complicated than those of Change and
Farjo, but it is also considerably more accurate and more useful for scientific
investigation
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