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9 V-Logic Principle forGenioplasty: Logical Approach forBalanced Chin
79
9.4 Surgical Techniques
In all cases, operations were done with lower gingivolabial incision extending to bilateral canines
leaving cuff under general anesthesia using
orotracheal intubation. Through the incision,
periosteum was identied and subperiosteal dissection was done to expose the midsymphysis.
During surgery, soft tissue detachment was done
minimally because blood supply should be set
aside for the survival of bony segments.
9.4.1 Basic Osteotomy
• Basic surgical procedure is horizontal osteotomy, which then evolves to two parallel horizontal osteotomy and oblique variation of
horizontal osteotomies.
• Vertical osteotomy of central chin to reduce
the width of chin is another basic surgical procedure. Combination of horizontal osteotomy
and vertical osteotomy is usually referred as
T-osteotomy.
• Lengthening genioplasty using central segment as a buttress is an application of
T- osteotomy. It provides sufcient amount of
lengthening with stability. Sophisticated
design in the central region requires experienced surgical technique.
• Contouring of lower mandibular border is
another basic surgical procedure, increasingly
required for smooth and aesthetic mandible
contour as there are more needs for combined
mandible reduction.
9.4.2 Types ofGenioplasty
Surgical procedures were rst divided into two
categories depending on the location of mental
foramen and further classied into eight types,
shown in Figs.9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, and
9.8. Each type was designed and decided accord-
ing to different vertical/horizontal length ratio of
the chin, infra-alveolar nerve anatomy, and the
patients’ needs (Table9.1).
Fig. 9.1 Classic T osteotomy. It is most commonly used reduction technique
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K. Lee and S. Park
Fig. 9.2 Two-parallel osteotomy
Fig. 9.3 Bow tie-shaped osteotomy
9 V-Logic Principle forGenioplasty: Logical Approach forBalanced Chin
81
Fig. 9.4 Diamond-shaped osteotomy
Fig. 9.5 Inverted V-shaped osteotomy
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K. Lee and S. Park
Fig. 9.6 Spade-shaped osteotomy
Fig. 9.7 Bird-shaped osteotomy
9 V-Logic Principle forGenioplasty: Logical Approach forBalanced Chin
83
Fig. 9.8 Diamond-shape osteotomy+inverted V-shaped osteotomy
Table 9.1 Types of genoiplasty
Normal nerve anatomy Low nerve anatomy
Narrowing Classic T-osteotomy Inverted V-shaped osteotomy
Shortening Two-parallel osteotomy
Bowtie- shaped osteotomy
Lengthening Diamond- shaped osteotomy Diamond-shaped osteotomy+inverted
9.4.3 Patients withNormal Nerve
Anatomy
vertical reduction to the patients with wide chins
who have sufcient space for osteotomy below
Spade-shaped osteotomy
Bird shaped osteotomy
V-shaped osteotomy
mental foramen. This method has both horizon-
9.4.3.1 Classic T Osteotomy
The procedure is called “T-osteotomy.” The
tal narrowing effect and vertical reduction
effect.
design is shown in Fig.9.1. This method is gener-
ally applied for simple narrowing of the chin that
has rather sufcient space for osteotomy with
high mental foramen.
9.4.3.3 Bow Tie-Shaped Osteotomy
The procedure is called “bow-tie shape osteot-
omy.” The osteotomy design is shown in Fig.9.3.
This method is compatible with patients who
9.4.3.2 Two-Parallel Osteotomy
The procedure is also called “Two-parallel osteotomy.” The osteotomy design is shown in
Fig. 9.2. This method is generally applied for
want more pointed chin rather than U-shaped
natural chin. There should be enough space
below the mental foramen because the design
involves diverging linear osteotomy line.
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K. Lee and S. Park
9.4.3.4 Diamond-Shaped Osteotomy
The procedure is so called “diamond-shaped
osteotomy.” The osteotomy design is shown in
Fig.9.4. This method is for vertical lengthening
of the chin without any bone graft. For this procedure, sufcient space below the mental foramen
is necessary. It has both horizontal narrowing and
vertical lengthening effects, so it’s recommended
when patients want longer and more pointed
chin.
9.4.4 Patients withLow Nerve
Anatomy
9.4.4.1 Inverted V-Shaped Osteotomy
This procedure is called “inverted V-shaped osteotomy.” The osteotomy design is shown in
Fig.9.5. This method is for vertical reduction for
patients who don’t have enough space for horizontal osteotomy below the mental foramen.
Through this method, the amount of vertical
reduction can be maximized because separated
segments moves not only medially but also
superiorly.
9.4.4.2 Spade-Shaped Osteotomy
The procedure is called “spade-shaped osteotomy.” The osteotomy design is shown in
Fig.9.6. This method is for vertical reduction.
This method can be applied for patients who
don’t have enough space below the mental fora-
men for horizontal osteotomy because it
involves inverted V-shaped design. And it also
can be applied for patients who want U-shaped
chin rather than pointed chin because medial
parts of separated chin segments rotate
superomedially.
9.4.4.3 Bird-Shaped Osteotomy
The procedure is called “bird-shaped osteot-
omy.” The osteotomy design is shown in
Fig. 9.7. This method is for vertical reduction
and especially for those who want more pointed
chin. This method can be applied for patients
who don’t have enough space mental foramen
for horizontal osteotomy because it involves
inverted V-shaped design. And it also can be
applied for patients who want pointed chin
because medial parts of separated chin segments
rotate inferiormedially.
9.4.4.4 Diamond-Shaped
Osteotomy+Inverted
V-Shaped Osteotomy
This procedure is combination of diamondshaped osteotomy with inverted V-shaped osteotomy. The design is shown in Fig. 9.8. This
method is for vertical lengthening of the chin for
patients with low nerve anatomy.
b
9 V-Logic Principle forGenioplasty: Logical Approach forBalanced Chin
9.5 Case Study
Case 1
A 24-year-old man complained of decient projection and wideness of chin. He wanted
improvement of the front and side prole. Considering ideal prole through panoramic X-ray
(Fig.9.9a) and AP X-ray (Fig.9.9b), inverted V-shaped osteotomy was performed. The wideness of chin was improved markedly after the surgery (Fig.9.10a, b).
85
a
Fig. 9.9 (Case 1) Preoperative panoramic X-ray (a) and AP X-ray (b)
a
b
Fig. 9.10 (Case 1) Postoperative panoramic X-ray (a) and AP x-ray (b)
86
b
b
Case 2
K. Lee and S. Park
A 28-year-old woman complained of shortness of chin. She wanted improvement of the front
prole. Considering ideal prole through panoramic X-ray (Fig. 9.11a) and AP X-ray
(Fig.9.11b), diamond + inverted V-shaped osteotomy was performed. The shortness of chin was
improved markedly after the surgery (Fig.9.12a, b).
a
Fig. 9.11 (Case 2) Preoperative panoramic X-ray (a) and AP X-ray (b)
a
Fig. 9.12 (Case 2) Postoperative panoramic X-ray (a) and AP x-ray (b)
b
9 V-Logic Principle forGenioplasty: Logical Approach forBalanced Chin
Case 3
A 25-year-old man complained of excessive length of chin. He wanted improvement of the front
prole. Considering ideal prole through panoramic X-ray (Fig. 9.13a) and AP X-ray
(Fig.9.13b), two-parallel osteotomy was performed. The length of chin was reduced markedly
after the surgery (Fig.9.14a, b).
a
Fig. 9.13 (Case 3) Preoperative panoramic X-ray (a) and AP X-ray (b)
87
a
Fig. 9.14 (Case 3) Postoperative panoramic X-ray (a) and AP x-ray (b)
9.6 Discussion
Balanced chin shape is determined by vertical
to horizontal ratio. V-logic is a principle to have a
Lower face contour has been thought to be
important for decades because it plays an important role in facial impression. Particularly,
Asians prefer slim V-shaped lower face rather
than wide lower face. For slim V-shaped lower
face, genioplasty is as important as mandibular
reduction itself. But classical genioplasty had
limitations that it could not be applied for all the
patients.
balanced vertical/horizontal ratio of chin. To
manage the shape of the chin, not only the verti-
cal length but also width is important. Some want
more pointed chin, and others want natural
U-shaped chin. This balance may vary greatly
and differ from people to people, nation to nation.
However, we should consult with patients about
general and individual balance. Ideal vertical to
horizontal ratio is usually 1:1.3.
b
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K. Lee and S. Park
It is not possible to fulll all these various
needs of the patients with only one classical surgical method. That is why various surgical methods are necessary. Genioplasty gets more and
more complex to pursue perfection and usually
involves both vertical and horizontal corrections
together. The amount of central resection usually
ranges 6mm to 12mm on average, while amount
of vertical reduction ranges 2 mm to 6 mm.
Lengthening genioplasty using central segment
as a buttress provides sufcient amount of lengthening. It also remains stable with minimal resorption comparing bone graft.
The location of mental foramen and course of
inferior alveolar nerve is the critical anatomical
factors. Variations such as low mental foramen
and low course of inferior alveolar nerve impose
a limitation in both vertical reduction and horizontal narrowing. On the given condition of anatomic variation, how to make a most desired and
still balanced result is the surgeon’s mission.
Laterally down oblique osteotomy is the variation for low mental foramen. Laterally up oblique
osteotomy is the variation for more pointed chin
shape.
It is necessary to dene anatomic variations
and decide the operation design preoperatively.
To decide the proper surgical plan according to
the current shape of the chin, anatomical variation, and patients’ request is the key point for
patients’ satisfaction.
Additional consideration should be taken in
detail to correct the asymmetry and AP relationship during surgery. Bilateral bony step-off
should also be corrected with contouring of the
mandible.
There were no cases of permanent nerve
injury. During the preoperative planning phase,
particular attention was given to the positioning
of the inferior alveolar nerve, emphasizing the
importance of minimal disruption to this area. To
further mitigate risk, the soft tissue surrounding
the mental foramen was carefully preserved from
excessive dissection or retraction. Postoperatively,
some patients required ancillary procedures to
address soft tissue drooping, including lifting and
liposuction of the cheek and submental area.
Additionally, for cases presenting with a bulky
and hyperactive mentalis muscle, botulinum
toxin injections were employed as an effective
postoperative intervention.
The chin is pivotal in shaping the overall
impression of the face. A slim, V-shaped chin of
appropriate length signicantly enhances the
attractiveness of the lower facial contour.
The V-logic principles, aimed at creating a
balanced chin, are outlined as follows:
1. The current state of the chin is thoroughly
analyzed across vertical, horizontal, and
anteroposterior dimensions, with special
attention to any asymmetry.
2. The desired shape of the chin is determined
based on the ideal vertical to horizontal ratio
and the patient’s specic requests, ensuring a
harmonious balance.
3. Attention is given to anatomical variations,
such as the positioning of the mental foramen
and the course of the inferior alveolar nerve.
4. Considering these variances, a spectrum of
surgical options is contemplated to address
individual needs effectively. Eight different
strategies are suggested according to the location of mental foramen, patient’s need, and
balanced chin shape.
5. Genioplasty is recognized as a multifaceted
procedure that encompasses horizontal narrowing, vertical adjustment (either reduction
or lengthening), and either advancement or
setback of the chin. These elements are tailored and synergistically combined for each
patient, aiming to transcend anatomical constraints and achieve optimal outcomes.
References
1. Lee TS, Kim HY, Kim TH, Lee JH, Park S.Contouring
of the lower face by a novel method of narrowing
and lengthening genioplasty. Plast Reconstr Surg.
2014;133:274–82.
2. Park S, Noh JH. Importance of the chin in lower
facial contour: narrowing genioplasty to achieve a
feminine and slim lower face. Plast Reconstr Surg.
2008;122:261–8.