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The Donor Site
1)Definition of the
Donor Site
2)Donor Site
Evaluation
3)Effective Use of
the Donor Site
4)Donor Site
Harvesting
Techniques
1) Definition of the
Donor Site
When hair-bearing
tissue is withdrawn
from one area of the
scalp for
transplantation to
an area that is
hairless due to
male-pattern hair
loss (MPHL), the
withdrawal is made
from the donor
site-an area
unaffected by the
genetics of MPHL.
The donor site in
the balding male is
hair-bearing scalp
tissue that runs
from an inch or two
above the ears and
temples to the back
of the head. This
donor area might be
called the
savings-and-loan
area: hair follicles
in this area are
saved from the
effects of MPHL and
are available for
loan by
transplantation to
scalp areas that
have lost hair due
to MPHL.
Transplanted hair
follicles from the
donor site retain
their resistance to
MPHL genes and
continue to produce
hair at the
recipient site.
In planning a hair
transplantation
procedure, the
physician hair
restoration
specialist will pay
as much attention to
the donor site as to
the recipient site.
Accurate assessment
and effective use of
hair-bearing tissue
at the donor site
are important
factors in the
eventual success of
hair transplantation
in any individual
patient.
The potential
“Permanent” donor
zone as determined
by an examination of
hair density in the
donor area in 328
randomly chosen men
aged 65 years or
older. Note that it
is 69mm high in the
midline of the
occipital area and
that hair with fewer
than 8 hairs per 4mm
circle is present
superior, inferior,
and anterior to the
shaded “safe”
donor area. (From
unger W, ed, hair
Transplantation, 3rd
ed, New York: Marcel
Dekker, 1995.)
Although the donor
area exists in all
male patients, it is
not precisely the
same and can vary
considerably from
patient to patient.
The physician hair
restoration
specialist will want
to identify the
"safe" hair-bearing
donor tissue that
will permanently
retain its
resistance to MPHL
genetic control.
Making this
identification
requires careful
evaluation by the
means of the
patient's family
history of hair loss
and by scalp
examination.
Hair-bearing tissue
that, at casual
examination, may
seem to be within
the general area of
a prospective donor
site may eventually
be lost to MPHL over
succeeding months to
years. Careful
evaluation
significantly
reduces the
possibility that the
hair-bearing tissue
chosen may
eventually be lost
to MPHL.
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2) Donor Site
Evaluation
Careful evaluation
of Donor area
includes:
A) Family hair-loss
history:
A
detailed look at a
patient's family
history of hair loss
can suggest a
probable pattern of
the patient's future
hair loss. A family
pattern of severe
hair loss may
indicate that the
"safe" area of a
donor site is
limited in size-that
is, it is probable
that the amount of
hair-bearing tissue
that will remain
resistant to MPHL is
limited, and this
will limit the
amount of donor
tissue that is
available for
transplantation.
B) Scalp examination:
In
MPHL, careful scalp
examination
indicates to an
experienced
physician hair
restoration
specialist where
future hair loss may
occur within the
prospective donor
site.
Evaluation of the
prospective donor
area by family
hair-loss history
and scalp
examination provides
information vital
for planning the
hair transplantation
procedure. However,
assessing the amount
of hair-bearing
tissue to be used
for transplantation
is considered in
context with other
important factors:
C) The age of the
patient:
Planning
the use of donor
hair may require
different strategies
for younger versus
older men. Younger
men with progressive
MPHL may need
several
transplantation
procedures over a
number of years to
keep pace with hair
loss, while older
men may need fewer.
If the donor area is
equated with a
savings-and-loan,
the strategy for
younger men is to
keep more donor hair
in reserve for
future use.
D) The type of hair
loss:
While
MPHL is progressive
for the lifetime of
a man, not all MPHL
progresses to its
most severe form.
(Click on Hair
Loss-Why? and
Norwood-Hamilton
Scale for
illustrations of
types of hair loss).
Treatment of a "high
forehead"
(Norwood-Hamilton
Type I) type of hair
loss may be all that
is needed by some
patients; for
example, in an older
man, "high forehead"
hair loss is
unlikely to progress
to a almost total
(Norwood-Hamilton
Type VII) type of
hair loss in the
patient's lifetime.
In a younger man,
"high forehead" hair
loss may progress to
a more severe form,
but if family
history and scalp
examination suggests
otherwise then
planning for
transplantation
should be based upon
the information
derived from history
and examination plus
the wishes of the
patient as discussed
with the physician
hair restoration
specialist.
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3) Effective Use of
the Donor Site
When MPHL hair loss
is substantial and
donor area is
limited, hair
restoration planning
may also include a
surgical procedure
such as scalp
reduction (Click on
Surgical Treatments
for information
about scalp
reduction) that will
reduce the area of
scalp that requires
transplantation. The
pros and cons of
this procedure
should be discussed
with the physician
hair restoration
specialist.
Assessment of the
donor area for
hair-bearing tissue
to use in
transplantation also
includes assessment
of hair
characteristics:
A) Hair density:
Hair occurs with
different densities
in different
locations within the
donor area. Hair
density is defined
as the number of
hairs per square
inch of scalp;
density varies at
different locations
on the scalp.
Harvesting of donor
tissue for
transplantation
takes hair density
in to account-for
example, transplant
grafts consisting of
multiple hair
follicles are best
taken from areas of
denser hair growth
within the donor
site.
B) Hair caliber:
The caliber
(cross-section) of
individual donor
hairs has
implications for an
appearance of
"fullness" or
"sparseness" of
transplanted
recipient areas.
Hairs of heavier and
finer caliber are
frequently
interspersed to
create a more
natural appearance
in the recipient
area.
C) Hair color:
The most natural
appearance in
recipient areas is
achieved by
appropriate balance
between the color of
donor hair and the
color of scalp skin
in the recipient
area.
D) Hair texture:
Hair texture ranges
from fine
"stringiness" to
"frizzy" fullness.
Each texture has
characteristics
useful in achieving
maximum naturalness
of appearance in the
individual patient.
The effective use of
hair texture is
heavily dependent on
the wishes of the
patient as discussed
with the physician
hair restoration
specialist.
E) Hair curl:
As with hair
texture, hair curl
is a characteristic
that can be used
effectively to
achieve the "look"
the patient wishes
to achieve. Markedly
curled hair-as in
men of African
ancestry-usually
grows from curved
follicles.
Walter Unger, MD,
one of the "fathers"
of modern hair
transplantation, has
observed that no
donor hair
characteristic is
better than any
other for achieving
the optimum outcome
for the individual
patient. The best
outcome is the one
that achieves the
wishes of the
patient and the
professional
satisfaction of the
physician hair
restoration
specialist.
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4) Donor Site
Harvesting
Techniques
Techniques for
harvesting donor
tissue have improved
steadily over the
years. Newer
techniques may
improve hair yield
as much as 50% to
100% over older
techniques. Newer
techniques generally
result in less
donor-site scarring
as compared to older
techniques. The
patient should ask
for a description
and explanation of
donor-site
harvesting as part
of full preoperative
discussion with the
physician hair
restoration
specialist.
Understanding of how
the donor site is to
be used is as
important to the
patient as
understanding how
donor tissue is to
be used in the
recipient site.
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