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Various Types of Minor Trauma to Hair Follicles During Follicular Unit Extraction for Hair Transplantation


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Background When performing follicular unit extraction (FUE), various types of minor hair follicle trauma unapparent during follicular unit strip surgery are likely to occur. However, no studies have examined such damage. Methods In total, 100 grafts were randomly selected from each of 42 patients who underwent FUE with a 1-mm-diameter sharp punch. A ×5.5 magnifying loupe and a ×60 magnifying binocular microscope were used. The transection rate (TR), paring, fractures of and damage to the dermal papilla (DP) areas, and hair bulb partial injury were assessed. Results Observation with the magnifying loupe revealed an average TR of 7.40%, and 4.31, 1.90, 1.52, and 0.43 hair follicles per 100 grafts exhibited paring, fracture, DP partial injury, and hair bulb partial injury, respectively. An average of 9.21 telogen hairs were observed. Microscopic examination revealed a TR of 6.34%, and 9.07, 1.95, 0.79, and 1.24 hair follicles per 100 grafts exhibited paring, fracture, DP injury, and hair bulb partial injury, respectively. An average of 16.62 telogen hairs were observed. Conclusions Various types of minor hair follicle damage occur during FUE as shown by loupe and microscopic examination of the grafts. Especially paring and hair bulb injury were more apparent under microscopic examination. These minor hair follicle injuries should be considered when choosing operative method or surgical techniques.
Content may be subject to copyright. 1
Since its first introduction in 2002, follicular unit ex-
traction (FUE) has become an increasingly more popular
method of obtaining donor hair.1
Despite the various advantages and disadvantages of FUE,
it is likely that more patients choose to undergo hair trans-
plantation by FUE than follicular unit strip surgery (FUSS)
because less pain and scarring is associated with FUE. Never-
theless, the efficacy of FUE has been questioned with respect
to whether its outcomes are equivalent to those of FUSS, the
most commonly employed procedure by many hair surgeons.
Some expert hair surgeons have simultaneously per-
formed FUSS and FUE in the same patient. Long-term
comparisons of the 2 methods have revealed much lower
follicle survival rates in FUE than FUSS (53.9% versus
85.2%, respectively).2 FUE-harvested grafts contain less
perifollicular tissue than do FUSS-harvested grafts, and
many physicians evidently believe this to be the main
cause of the lower survival rate of harvested follicles in
FUE than FUSS. Nonetheless, the same expert surgeons
have found that there is a tendency toward a larger de-
viation of surgical outcomes of FUE than FUSS. In cases
in which the same surgeon consistently harvested the fol-
licles by the same method, both excellent and poor results
were observed. This raises 2 important clinical questions:
What characteristics of FUE-obtained grafts, other than
the smaller amount of perifollicular tissue compared
with FUSS-obtained grafts, contribute to this variation in
outcomes? How does the appearance of FUE- and FUSS-
obtained grafts differ under a microscopic and high-mag-
nification loupe?
Microscopic dissection is generally chosen for FUSS.
However, although an approximately ×5 magnifying loupe
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DOI: 10.1097/GOX.0000000000001260
From the Dana Plastic Surgery Clinic, Gangnam-gu, Seoul, Korea.
Received for publication October 14, 2016; accepted January 20,
Background: When performing follicular unit extraction (FUE), various types of
minor hair follicle trauma unapparent during follicular unit strip surgery are likely
to occur. However, no studies have examined such damage.
Methods: In total, 100 grafts were randomly selected from each of 42 patients who
underwent FUE with a 1-mm-diameter sharp punch. A ×5.5 magnifying loupe and
a ×60 magnifying binocular microscope were used. The transection rate (TR), par-
ing, fractures of and damage to the dermal papilla (DP) areas, and hair bulb par-
tial injury were assessed.
Results: Observation with the magnifying loupe revealed an average TR of 7.40%,
and 4.31, 1.90, 1.52, and 0.43 hair follicles per 100 grafts exhibited paring, fracture,
DP partial injury, and hair bulb partial injury, respectively. An average of 9.21 telo-
gen hairs were observed. Microscopic examination revealed a TR of 6.34%, and
9.07, 1.95, 0.79, and 1.24 hair follicles per 100 grafts exhibited paring, fracture, DP
injury, and hair bulb partial injury, respectively. An average of 16.62 telogen hairs
were observed.
Conclusions: Various types of minor hair follicle damage occur during FUE as
shown by loupe and microscopic examination of the grafts. Especially paring and
hair bulb injury were more apparent under microscopic examination. These mi-
nor hair follicle injuries should be considered when choosing operative method
or surgical techniques. (Plast Reconstr Surg Glob Open 2017;5:e1260; doi: 10.1097/
GOX.0000000000001260; Published online 16 March 2017.)
Jae Hyun Park, MD, PhD
Seung Hyun You, MD
Various Types of Minor Trauma to Hair Follicles
During Follicular Unit Extraction for Hair
Disclosure: The authors have no financial interest to
declare in relation to the content of this article. The Article
Processing Charge was paid for by the authors.
PRS Global Open 2017
is recommended for FUE, some surgeons perform this
procedure with the naked eye or by wearing a simple ×1.5
or ×2.0 magnifying glass. The grafts harvested in this way
might then be inspected by the naked eye, a ×1.5 to ×2.0
magnifying glass, and a ×5 magnifying loupe to confirm
whether they are intact or properly transected.
Until now, we have only considered either the occur-
rence of transection or the presence of intact grafts to
assess the quality of follicles harvested by either FUE or
FUSS. We believe that the transection rate (TR) provides
valuable information about the quality of FUE surgery.
However, in addition to simple transection, the occur-
rence of other types of minor trauma to the follicles har-
vested by FUE is probable, and these types of trauma are
rarely seen in FUSS.
FUSS lacks various potentially traumatic processes
such as dissection using a rotating or oscillating punch
and extraction using aid-to-extraction forceps or jeweler’s
forceps. Hence, in the present study, we aimed to identify
other types of hair follicle injuries that can occur in addi-
tion to transection.
To the best of our knowledge, no reports have ad-
dressed the nature and extent of these types of minor
hair follicle trauma. Therefore, we conducted the present
study to determine the frequency and nature of minor
trauma that occurs during FUE surgery.
This study included 42 patients (38 males and 4 fe-
males) at the authors’ clinic. Using a 1-mm-diameter
sharp punch, 100 follicles were randomly selected from
each patient. In total, 4200 grafts were analyzed.
Patients with a history of hair transplant surgery, infec-
tious disease, or trauma in the donor area were excluded
from the study. The patients’ age distribution ranged from
28 to 52 years, and the mean age was 32.6 years. All male pa-
tients exhibited Norwood stage 3 to 5 male pattern baldness.
All female patients were undergoing female hairline correc-
tion without female pattern hair loss. The donor area of all
patients was shaved in the form of a total or partial patch for
FUE. This study was approved by the internal institutional re-
view board of the Korea National Institute of Bioethics Policy.
FUE Procedure
All punching was performed by 1 expert hair surgeon
(Dr. Park). A 1-mm sharp punch of the Folligraft system
(LeadM Corp., Seoul, Korea) was used. The surgical pro-
cedure was implemented in the same manner as routinely
performed during a normal FUE operation. A FOX test was
conducted at the beginning and in the middle of the sur-
gery, while the punching depth was modified. The punching
depth achieved was within 2.5 to 3.5 mm (mean, 2.9 mm).
All injuries were divided into 5 types: transection, par-
ing, fracture, dermal papilla (DP) injury, and hair bulb
partial injury. The presence or absence of such injuries
was confirmed in all patients. A ×5.5 magnifying loupe and
×60 magnifying binocular microscope were employed for
analysis. If none of the above-described 5 types of injury
was present, the hair follicle was considered intact.
Statistical Analysis
An independent-samples t test was conducted to deter-
mine the differences in the types of partial injuries in all
The TR was 7.40% based on microscopic observation
and 6.34% based on loupe observation. The difference
in these rates was not significantly different (P > 0.05).
However, the 2 observation methods showed significantly
different numbers of telogen hairs: an average of 9.21 fol-
licles based on loupe observation and an average of 16.62
follicles based on microscopic observation (P < 0.001;
Table 1).
Paring was present in approximately 4.31 follicles
based on loupe observation and 9.07 follicles based on mi-
croscopic observation; microscopic observation showed a
2-fold higher number of affected follicles, and the differ-
ence was statistically significant (P < 0.000).
DP partial injury affected an average of 0.52 follicles based
on loupe observation and 0.79 follicles based on microscopic
observation with no significant difference (P > 0.243).
Bulb injury affected an average of 0.43 and 1.24 fol-
licles based on loupe and microscopic observation, respec-
tively, with a significant difference (P < 0.003).
Finally, an average of 1.90 follicles were fractured based
on loupe observation and an average of 1.95 follicles were
fractured based on microscopic observation, with no sig-
nificant difference between the 2 methods (P > 0.858).
Trauma was more frequently found in association with
all types of damage under microscopic examination. How-
ever, a statistically significant difference appeared only for
paring and bulb injury (Fig. 1).
Generally, patients prefer FUE to FUSS for obtaining
donor hair, although the follicle survival rate remains con-
troversial because of less postoperative pain and to avoid
linear donor scar.3
Table 1. Comparative Analysis of FUE-extracted Grafts
Using a Loupe and Microscope
Minimum Maximum Average
TR (%) 1.3 17.3 7.40
Paring 0 17 4.31
Fracture 0 4 1.90
DP injury 0 3 0.52
Hair bulb partial
0 3 0.43
Telogen 0 22 9.21
Microscope TR (%) 1.3 15.89 6.34
Paring 2 20 9.07
Fracture 0 4 1.95
DP injury 0 4 0.79
Hair bulb partial
0 7 1.24
Telogen 3 37 16.62
TR = transected hair follicle/total number of hair follicles harvested. Paring,
fracture, DP injury, and hair bulb injury: number of hair follicles found with
each injury per 100 follicles. Telogen: number of telogen hair follicles found
per 100 grafts.
Park and You Types of Minor Trauma to Hair Follicles During FUE
Despite the fact that FUSS can have phenomenal re-
sults with respect to minimal scarring when the tricho-
phytic closure strategy is used, this is a benefit generally
seen from the doctor’s point of view and may differ from
the patient’s perspective. From the patient’s point of view,
FUE is a more minimally invasive and patient-friendly
Regardless, successful and consistent results of FUE
are still being demanded. The type of surgery that would
be considered a successful FUE surgery remains unclear.
When comparing FUE with FUSS, the TR and calculated
density are often compared, and the TR is often examined
by itself.5–7 The TR is undoubtedly a very important fac-
tor that must be considered during surgery, but a lower
TR in association with a high follicle survival rate is also
an imperative factor to be considered. Fewer studies have
evaluated the follicle survival rate in FUE. Beehner8 per-
formed FUE and FUSS simultaneously in the same patient
and reported an 85.2% follicle survival rate in FUSS and a
53.9% follicle survival rate in FUE.
Many researchers and hair surgeons believe that the
reason for the difference in the survival rate between FUE
and FUSS is the difference in the amount of perifollicu-
lar tissue between the 2 types of grafts. A thicker graft is
associated with a higher follicle survival rate; this fact is
recognized as the most basic concept of hair transplanta-
tion. Many other factors may also affect the follicle sur-
vival rate, such as the out-of-body time, dryness, physical
trauma, and surgeon’s implantation skills.9
In the present study, no paring, fracture, DP injury, or
bulb damage was observed while affirming the randomly
selected follicles under a microscope; all of these follicles
were arbitrarily acquired by FUSS and analyzed as a fol-
licular unit by a highly experienced surgical assistant.
How specifically and practically hair follicle trauma af-
fects the survival rate remains unknown. However, based
on our literature review, it is possible to infer that the mi-
nor trauma described in this report has more negative
effects on hair follicles than intact and perfectly condi-
tioned grafts with no minor trauma.
Fig. 1. Various types of follicle injury that are likely to occur during FUE (×60 magnication). A, Total transection. B, Partial transection. C,
Paring. D, DP injury. E, Bulb injury. F, Fracture. G, Telogen.
PRS Global Open 2017
Hair follicle stem cells are not a single multipotent
entity given that a pilosebaceous unit contains numerous
stem cell populations and subpopulations ranging from
epithelial to mesenchymal and melanocyte stem cells. The
epithelium comprises the hair shaft, inner root sheath,
and outer root sheath (ORS). The isthmus is the region
between the entry of the sebaceous duct and the inser-
tion of the arrector pili muscle. The isthmus includes the
“bulge” region (otherwise known as the basal, outermost
ORS layer of the distal hair follicle epithelium at the prox-
imal end of the isthmus), which contains the epithelial
hair follicle stem cells. The DP and dermal sheath of the
follicle are mesenchymal in origin and have been shown
to harbor multipotent stem cell subpopulations distinct
from epithelial hair follicle stem cells, such as skin-derived
precursors, NESTIN+ cells, or SOX2+ cells.10–12
Hair follicle morphogenesis and regeneration depend
on intensive but well-orchestrated interactions between
epithelial (bulge stem cells, their descendent secondary
hair germ cells, and hair matrix cells) and mesenchymal
(DP and dermal sheath) components.10–13 Thus, both DP
stem cells and epithelial stem cells are important, and hair
growth is reportedly degraded if either is missing.
Each type of trauma described in this study is shown in
detail in Figure 1. First and foremost is transection, which
can occur not only during the strip incision process of
FUSS but also during dissection in FUE. The transected
donor hair follicle obtained by FUE remains in the donor
scalp tissue; in FUSS, however, it completely dissipates.
The second type of injury is paring. Paring refers to lac-
eration or avulsion of the ORS by the punch tip (Fig. 2).14
The third injury is fracture. A fracture is defined as
separation of either end of the hair follicle into 2 or more
pieces due to stress at some point along the length of the
follicle.14 The cause of a fracture is rotation of the punch
tip, which partially traumatizes the hair follicle like a lac-
eration, resulting in injury to the ORS and the hair shaft
on one side; the ORS and partial hair shaft on the other
side remain intact, maintaining the overall continuity of
the follicle (Fig. 2). Theoretically, fractures occur more
frequently under circumstances of increased axial force
such as rubbery skin; long, thick hair follicles; hyperelastic
skin; and use of a blunt punch tip.15
The fourth type of trauma is DP injury. This occurs
due to an insufficient punching depth when considering
the adhesion between the perifollicular tissue and the
hair follicle. When the depth is too superficial for extrac-
tion, the tissues of the ORS encompassing the hair bulb
and DP can likewise be detached or torn out. Therefore,
from a clinical perspective, when conducting the extrac-
tion, the surrounding scalp tissues can be elevated by tag-
ging along the graft, which can suddenly break off later,
resulting in frequent DP injuries. If the punch tip enters
even deeper than the minimal punching depth, it can
reach a segment where extraction of the hair follicles can
be conducted in a smoother, easier manner without hav-
ing to increase the TR. The authors refer to this as the
safe punching depth.
The fifth type of trauma is bulb partial damage. This
is another very important factor that may be overlooked.
A partially damaged hair follicle will be considered intact
if it does not contribute to the TR, which we have recog-
nized. However, it is highly likely to affect the survival rate.
An important fact that matters in the present study is that
such types of damage to the hair bulb frequently occur
in many cases and that they can usually be visualized only
under a ×60 magnifying microscope and not through a
×5 to ×6 magnifying loupe, which is routinely used during
FUE. Trauma to the hair bulb such as damage, crushing,
or partial avulsion are thought to profoundly affect the
survival of hair follicles. From a comprehensive viewpoint,
not only are a too superficial punching depth and inad-
equate extraction undesirable, but a too deep punching
depth should be avoided as well.
Fig. 2. Concept schema for easy understanding of paring, fracture, and transection.
Park and You Types of Minor Trauma to Hair Follicles During FUE
The main limitation of this study is that transection
and other types of minor trauma were dependent upon
the operators’ skill levels and variations in techniques.
We consider that a further study is required to gain a
better understanding of the effects of various types of
trauma on the survival rate of damaged follicles. We also
believe that an additional study should be conducted to
determine how these types of trauma vary depending
on various FUE techniques and skin and hair charac-
This study confirms the existence of diverse types of
damage to hair follicles obtained through FUE. Such graft
damage was less often detected by a ×5 to ×6 magnifying
loupe, which is routinely used during FUE, than with a
×60 microscope. The present study will serve as a baseline
for additional studies on this topic, enabling researchers
to discover better surgical techniques that ensure satisfac-
tory results for both the doctor and the patient.
Jae Hyun Park, MD, PhD
Dana Plastic Surgery Clinic
Samju Building 10F
Gangnamdaero 606, Gangnam-gu
Seoul, Korea
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... Two main reasons for failure of hair transplantation using FUE were the unhealthy follicles extracted from regions prone to hair loss ) and damage of the grafts during extraction (Park and You 2017). Hair follicle units are extracted using small punches with diameters of 0.6-1 mm Nuri et al. 2021). ...
Full-text available
Intact and healthy hair follicles are important for hair growth after hair follicle transplantation. However, effective and practical evaluation methods for the quality of hair follicles are currently lacking. In the present study, we developed a novel fast staining method for histological examination of hair follicles. The whisker follicles from mice were used to explore the staining protocols, and the final protocol for the evaluation of human hair follicles was derived from animal experiments. After extraction, human hair follicles or mouse whisker follicles were permeabilized with 0.3% Triton X-100. Subsequently, hair follicles were processed by either hematoxylin or alkaline phosphatase staining. The integrity and growth state, including the status of hair follicle stem cells and blood vessels of the extracted hair follicles, were clearly identified under a light microscope. Unhealthy hair follicles from donors or hair follicles broken during extraction were easily revealed by this method. Importantly, it took less than half an hour to obtain images of an individual hair follicle. This method is simple and practical for evaluating the quality and status of hair follicles, providing a fast-screening procedure for hair follicle transplantation.
... It is postulated that FUE leads to lower graft survival than FUT, due to the higher risk of transection during extraction of the graft. 39 However, studies comparing the 2 techniques in the treatment of androgenic alopecia have demonstrated mixed results, with some showing FUE resulting in inferior graft survival and others showing equivalent survival rates. 40,41 Many authors have suggested that careful handling of grafts when performing the FUE technique can reduce the risk of transection, and subsequently improve graft survival rates. ...
Background: Facial hair transplantation has become an increasingly popular modality to create a more masculine appearance for transmasculine patients. Objectives: This aim of this study was to review the current literature regarding facial hair transplantation and provide recommendations and best practices for transgender patients. Methods: A comprehensive literature search of the PubMed, MEDLINE, and Embase databases was conducted for studies published through April 2020 for publications discussing facial hair transplant in transmasculine patients, in addition to the nontransgender population. Data extracted include patient demographics, techniques, outcomes, complications, and patient satisfaction. Results: We identified 2 articles discussing facial hair transplantation in transmasculine patients. Due to the paucity of publications describing facial hair transplantation in transmasculine patients, data regarding facial hair transplant from the cisgender population were utilized to augment our review and recommendations. Conclusions: Facial hair transplant is a safe and effective means of promoting a masculine appearance for transgender patients. Nevertheless, facial hair transplantation should be deferred until at least 1 year after the initiation of testosterone therapy to allow surgeons to more accurately identify regions that would benefit the most from transplantation. Additionally, providers should engage patients in discussions about any plans to undergo facial masculinization surgery because this can alter the position of transplanted hairs. Currently, follicular unit extraction from the occipital scalp is the preferred technique, with use of the temporal scalp if additional grafts are needed. Patients should be advised that a secondary grafting procedure may be needed a year after initial transplant to achieve desired density. Level of evidence: 4:
Background: In Follicular Unit Excision (FUE), the concept of Depth Control (DC) has been created to minimize the risk of hair follicle damage. Aim: To analyze DC variation in different parts of the safe donor area of scalp; to propose Boaventura's new DC classification for hair restoration surgery using the FUE technique. Patients/methods: Thirty male patients underwent hair restoration surgery. The donor area was distributed into 14 zones, with the minimum depth required for at least three atraumatic extractions of the grafts. When the extraction was not successful, 0.5 mm was added until reaching three follicular units, determining the DC area. Results: Approximately 2000 extractions were performed on each patient to determine DC. For some areas, greater depth (2.54±0.10 mm) was necessary. 58% of follicular units were extracted with 2.0 mm DC, and 3.8% required 3.5 mm DC. Thus, according to Boaventura's new classification for DC, grade I ≥ 2.00 mm, grade II from 2.1 to 3 mm, and grade III > 3.0 mm. Conclusion: There is variability in the DC of follicular units within the different areas of the safe donor zone. Moreover, we have proposed a new DC classification, which would represent a valuable estimation of surgery demand.
Modern hair restoration surgery is based on a technique known as follicular unit transplantation in which follicular units (FUs) are the exclusive structures used as hair grafts. In Part 1 of this two-part review, we describe how the techniques employed in hair transplantation have evolved into their present forms. Anatomic concepts of specific relevance for dermatologists are discussed, including the distribution and ex-vivo morphology of scalp FUs. Male androgenetic alopecia and female pattern hair loss are the most common reasons for hair loss consultations with dermatologists and will be the primary focus of this review. However, as not all hair disorders are suitable for transplantation, this review will also describe which scalp conditions are amenable to surgery and which are not. In addition, guidelines are provided to help dermatologists better define good or bad candidates for hair transplantation. Finally, other conditions for which hair transplantation surgery is indicated are reviewed.
Background: Various types of follicular trauma occur during follicular unit excision (FUE). However, the effects of different types of follicular injury on graft survival have not been reported. Objective: This study was performed to evaluate the differences in hair follicle survival by the type of follicular injury, including paring, fracture, and bulb injury. Methods: Seven healthy patients who underwent hair transplant surgery by FUE were enrolled in the study. For each patient, 10 single-hair follicular unit grafts per injury group (paring, fracture, bulb injury, or intact) were differentiated. Using sharp implanters, 10 grafts of each of the 4 injury types were transplanted into mice, and the mice were sacrificed 5 months after transplantation. The skin was excised at each of the 4 locations, and newly formed follicular units were counted and photographed under a microscope. Results: Of 70 hair follicles in each group, the number of successfully engrafted follicles was 50 (71.43%) in the intact group, 36 (51.43%) in the paring injury group, 9 (12.86%) in the fracture injury group, and 31 (44.29%) in the bulb injury group. Conclusion: Grafts with minor injury had a lower survival rate than intact grafts. Fractured follicles showed the lowest survival rate.
Background: Follicular unit excision (FUE) and follicular unit transplantation using strip surgery (FUT) are the dominant graft harvest methods in hair transplantation. The increase in the demand for FUE has reignited the debate of the relative superiority of the 2 methods. Objective: To present a critical comparison of FUE and FUT graft harvesting techniques. Materials and methods: Search of PubMed, trade publications, and printed references. Results: Follicular unit excision and FUT methods provide high-quality grafts, but differ in their scarring patterns of the donor region. Follicular unit transplantation results in a linear scar, whereas FUE produces punctate scars that are typically easily concealed. Distinct subgroups of hair transplant patients are eligible for FUE, FUT, or both procedures. Conlcusion: Both FUE and FUT are equally effective in generating high-quality grafts. This detailed evaluation of the FUT and FUE procedures will assist hair restoration surgeons make informed decisions about the best approach for their patients.
Background: Although the follicular unit excision/extraction (FUE) is regarded an easy procedure to perform, however, there are various factors which affect the outcome. The hair transection is dependent of various factors and the donor site characteristics affect largely. Objectives: To know the difference in transection rate on various areas of scalp during FUE. Materials and methods: The study was conducted in 10 patients undergoing FUE after obtaining informed consent. In each patient, 1 row was marked with intervening 1 cm2 . The row contained five boxes of 1 cm2 . Harvesting of FUs was performed using 0.9 mm serrated punch. The procedures were performed with the patient in supine position with the surgeon sitting on head side. The harvested FUs were checked under microscope. Any transection was calculated. All the data was collected and analyzed statistically. Results: The total number of FUs and hair were more in center zone as compared to the sides. Whereas, the transection rate was lowest in the mid-occipital zone as compared to the sides. Similarly, the FUs: hair ratio was more in the sides 1:1.85 as compared to 1:1.62 in central zone. The right and left sides also showed some variations. The transection was more on right side (17.7%) of the patient as compared to the left side (16.3%) CONCLUSION: The hair transection was more on sides than in the mid-occipital area.
Objectives: To compare the transection rate at the start and at the end of the FUE procedure. Materials and methods: The study was conducted in a private setup in patients undergoing first session of FUE surgery over 2000 grafts. Six areas of 1 cm2 were marked, two in midline and two on either side. All the procedures were undertaken by the single surgeon to avoid any bias. At the start of the surgery, the extraction of hair was performed in areas A1, A2, and A3. All the excised hair and transected hair were counted. The surgery was then completed but the remaining three areas (B1, B2, and B3) were left intact. Later, FUE was done in these areas. The excised hair and transected hair were counted. All the data were analyzed statistically by paired t test. Results: A total of 25 patients were included in the study. The mean age of the patients was 35.2 years. The transection rate was 5.3/cm2 in mid-zone, 4.4/cm2 on right side, and 5.7/cm2 on left side at the start and 27.7/cm2 in mid-zone, 25.6/cm2 on right side, and 24.2/cm2 on left side at the end. The transection rate increased from 5.03 to 6.0/cm2 for FUS <2500 but increased from 4.83 to 6.6/cm2 with FUs over 2500 and increased from 5.5 to 6.67/cm2 when FUs were over 3000. Conclusion: The surgeon's workload increases the hair transection during FUE.
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Background Recently, an automated robotic hair restoration device was developed and is increasingly being used for hair restoration. Objective We sought to analyze the hair follicles of Korean patients that were harvested by a hair restoration robotic device. Methods Data were reviewed from a total of 22 patients who underwent robotic follicular unit (FU) extraction hair restoration surgery at Seoul National University Bundang Hospital. Hair follicles collected from 3 grids in the central parts of the safe donor zone of each patient were analyzed. Results The total number of harvested FUs was 5213, and the total number of collected FUs was 4955. The average yield was 95.1% ± 3.5%. Among the 12,017 harvested hairs, 590 hairs were transected and the average transection rate was 4.91% ± 2.9%. FUs of double hairs made up the majority of harvested FUs (44.1%), followed by triple hairs (31.9%). The transection rate increases in FUs that contain multiple hairs. Limitations A relatively small sample size and lack of comparative study with conventional FU extraction modalities are limitations. Conclusions The robotic system qualifies for use in hair restoration surgery. It efficiently harvests not only single hairs but multiple hairs as well.
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Success in follicular unit extraction requires an understanding of forces, fluid dynamics, instrumentation, and individual patient variation. Sharp punches require a lower axial and tangential force to dissect follicular groups. The angle of hair emergence and the size of a punch influence the wound size and the depth of an incision. A procedure must be individualized based on surface follicular group characteristics; hair splay; and strength of attachment between the outer root sheath, inner root sheath, and adipose with regard to hair follicles.
Follicular unit extraction (FUE) has been performed for over a decade. Our experience in the patients who underwent hair transplantation using only the FUE method was included in this study. A total of 1000 patients had hair transplantation using the FUE method between 2005 and 2014 in our clinic. Manual punch was used in 32 and micromotor was used in 968 patients for graft harvesting. During the time that manual punch was used for graft harvesting, 1000-2000 grafts were transplanted in one session in 6-8 h. Following micromotor use, the average graft count was increased to 2500 and the operation time remained unchanged. Graft take was difficult in 11.1 %, easy in 52.2 %, and very easy in 36.7 % of our patients. The main purpose of hair transplantation is to restore the hair loss. During the process, obtaining a natural appearance and adequate hair intensity is important. In the FUE method, grafts can be taken without changing their natural structure, there is no need for magnification, and the grafts can be transplanted directly without using any other processes. Because there is no suture in the FUE method, patients do not experience these incision site problems and scar formation. The FUE method enables us to achieve a natural appearance with less morbidity. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors .
Follicular Unit Transplantation (FUT) is performed using large numbers of naturally occuring individual follicular units obtained by single-strip harvesting and stereo-microscopic dissection. Donor wound scarring from strip excision, although an infrequent complication, still concerns enough patients that an alternative solution is warranted. The purpose of this paper is to introduce Follicular Unit Extraction (The FOX Procedure), in which individual follicular units are removed directly from the donor region through very small punch excisions, and to describe a test (The FOX Test) that determines which patients are candidates for this procedure. This paper explores the nuances, limitations, and practical aspects of Follicular Unit Extraction (FUE). FUE was performed using 1-mm punches to separate follicular units from the surrounding tissue down to the level of the mid dermis. This was followed by extraction of the follicular units with forceps. The FOX test was developed to determine which patients would be good candidates for the procedure. The test was performed on 200 patients. Representative patients who were FOX-positive and FOX-negative were studied histologically. The FOX Test can determine which patients are suitable candidates for FUE. Approximately 25% of the patients biopsied were ideal candidates for FUE and 35% of the patients biopsied were good candidates for extraction. FUE is a minimally invasive approach to hair transplantation that obviates the need for a linear donor incision. This technique can serve as an important alternative to traditional hair transplantation in certain patients.
The purpose of this article is to introduce the reader to the topic of follicular unit extraction (FUE) and to present an overview of the value of FUE to patients and physicians. In addition to this, the various methods and instrumentation for performing this method of graft harvest are discussed as well as some of the technique's inherent advantages and disadvantages. Topics unique to FUE, including body hair grafting, plug/minigrafts repair, and donor area management are addressed as well.
Hair follicle morphogenesis and regeneration depend on intensive but well-orchestrated interactions between epithelial and mesenchymal components. Accordingly, the enhancement of this crosstalk represents a promising approach to achieve successful bioengineering of human hair follicles. The present article summarizes the techniques, both currently available and potentially feasible, to promote epithelial-mesenchymal interactions (EMIs) necessary for human hair follicle regeneration. The strategies include the preparation of epithelial components with high receptivity to trichogenic dermal signals and/or mesenchymal cell populations with potent hair inductive capacity. In this regard, bulge epithelial stem cells, keratinocytes predisposed to hair follicle fate or keratinocyte precursor cells with plasticity may provide favorable epithelial cell populations. Dermal papilla cells sustaining intrinsic hair inductive capacity, putative dermal papilla precursor cells in the dermal sheath/neonatal dermis or trichogenic dermal cells derived from undifferentiated stem/progenitor cells are promising candidates as hair inductive dermal cells. The most established protocol for in vivo hair follicle reconstitution is co-grafting of epithelial and mesenchymal components into immunodeficient mice. In theory, combination of individually optimized cellular components of respective lineages should elicit most intensive EMIs to form hair follicles. Still, EMIs can be further ameliorated by the modulation of non-cell autonomous conditions, including cell compartmentalization to replicate the positional relationship in vivo and humanization of host environment by preparing human stromal bed. These approaches may not always synergistically intensify EMIs, however, step-by-step investigation probing optimal combinations should maximally enhance EMIs to achieve successful human hair follicle bioengineering.
Hair transplantation has come a long way from the days of Punch Hair Transplant by Dr. Orentreich in 1950s to Follicular Unit Hair Transplant (FUT) of 1990s and the very recent Follicular Unit Extraction (FUE) technique. With the advent of FUE, the dream of 'no visible scarring' in the donor area is now looking like a possibility. In FUE, the grafts are extracted as individual follicular units in a two-step or three-step technique whereas the method of implantation remains the same as in the traditional FUT. The addition of latest automated FUE technique seeks to overcome some of the limitations in this relatively new technique and it is now possible to achieve more than a thousand grafts in one day in trained hands. This article reviews the methodology, limitations and advantages of FUE hair transplant.