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S. Park
4.3 Surgical Instruments
4.3.1 Zygoma Reduction
In the realm of reduction malarplasty, the
L-shaped osteotomy technique has gained widespread popularity [1–8]. This technique often
incorporates a dual approach: an ostectomy and
posteromedial repositioning of the zygomatic
body via an intraoral approach, coupled with an
osteotomy and inward repositioning of the zygomatic arch through a preauricular or sideburn
incision. During this procedure, the surgeon must
make several critical decisions [1].
The amount of bone resection in the zygomatic body is a pivotal factor, as it determines the
decrease in bimalar width due to the medial repositioning of the zygomatic bone. Achieving uniform resection is crucial, and this can be
facilitated by using a “double-bladed” reciprocating saw. These saws come in various sizes, with
blade distances ranging from 2 to 7mm (Fig.4.1),
to ensure precise and equal bone resection. In
cases where there is asymmetry in the zygomatic
region, different saws can be selected based on
the preoperative analysis.
Additionally, the extent of posterior setback of
the zygomatic body needs to be carefully determined. In patients with a prominent zygoma, the
maximal malar projection (MMP) is often malpositioned anterolaterally. Therefore, a combined
medial repositioning and posterior setback of the
zygomatic body is necessary. Pre-bent titanium
plates, available in different sizes (Fig.4.2), can
be used to accurately perform this setback procedure. The size of the step in each plate varies,
allowing for precise repositioning of the zygomatic body, both in symmetrical and asymmetrical cases.
Furthermore, the amount of medial repositioning required for the zygomatic arch is a critical
consideration. Patients with a prominent zygoma
usually exhibit a prominence in the arch region
that needs to be repositioned inwardly. This is
achieved by cutting through the zygomatic arch
via a sideburn incision and then pushing the anterior portion of the arch inwardly for rigid xa-
a
b
Fig. 4.1 “Double-bladed” reciprocating saws used in
reduction malarplasty, highlighting their role in ensuring
precise and equal bone resection in the zygomatic body
region during an L-shaped osteotomy
Fig. 4.2 Pre-bent titanium plates utilized in reduction
malarplasty. These plates come in various sizes and are
used for the xation of the zygomatic arch and body,
enabling rigid and accurate bone repositioning
t.me/Dr_Mouayyad_AlbtousH
4 Customized Instruments forFacial Bone Contouring Surgery
23
tion. Pre-bent titanium plates, specically linear
three-hole plates with step sizes ranging from 0
to 4mm (Fig.4.2), can be used for this purpose,
with the choice of plate depending on the extent
of lateral prominence in the arch region.
4.3.2 Mandible Reduction
The conventional technique for mandible reduction involves the use of an oscillating saw through
an intraoral approach [9–11]. Prior to the main
osteotomy, a “guarded” oscillating saw marks the
proposed osteotomy line [12, 13]. This saw features a small oscillating blade shielded at various
distances, ranging from 2 to 6 mm (Fig. 4.3),
allowing for precise control over the extent of
bone resection. The choice of guarded saw
depends on the required amount of resection in
a
the mandibular body and the proximity to the
inferior alveolar nerve. Utilizing these guarded
saws ensures uniform bony resection and reduces
the risk of unintentional over-resection and nerve
injury. Additionally, in cases with jawline asymmetry, different-sized guarded saws can be used
to differentially correct the asymmetry. Following
initial cuts with a guarded saw, larger oscillating
saws complete the bone resection.
4.3.3 Genioplasty
Genioplasty stands out as one of the most versatile and practical tools in facial bone surgery,
often performed independently or in conjunction
with other facial bone surgeries [14]. It addresses
issues such as a small or protruding chin by repositioning it anteroposteriorly [15, 16]. For chin
narrowing or vertical shortening procedures
requiring bone resection, double-bladed reciprocating saws are used to achieve precise, equal
osteotomies (Fig.4.4) [17]. During chin advancement or setback, pre-bent plates control the
anteroposterior adjustments. These plates come
in various sizes, and the appropriate one is
selected based on preoperative cephalometric
analysis, allowing for precise execution of the
planned chin repositioning (Fig.4.5).
b
Fig. 4.3 “Guarded” oscillating saws used in mandibular
angloplasty, showing how these tools guide precise bone
resection while protecting against over-resection and
nerve injury
t.me/Dr_Mouayyad_AlbtousH
Fig. 4.4 A double-bladed reciprocating saw used in genioplasty for equal bone resection during chin narrowing or
vertical shortening procedures
24
Fig. 4.5 Pre-bent titanium plates used in genioplasty,
which assist in controlling the degree of anteroposterior
adjustment during chin advancement or setback
4.4 Discussion
Complications in facial bone contouring surgery
can arise from errors in patient evaluation or
operative techniques. Standard surgical
instruments, like those described here, can mitigate the risk of such outcomes. Common complications include edema, hematoma, infection,
soft-tissue sagging, and sensory disturbances.
Utilizing double- bladed reciprocating saws can
increase the accuracy of osteotomies, reducing
postoperative asymmetry and the risk of underor overcorrection. Pre-bent plates facilitate precise repositioning of the zygomatic body and
arch, enhancing surgical outcomes.
In mandibular reduction, complications like
inferior alveolar nerve injury and jawline contour
irregularities can be minimized with careful planning and technique [18–25]. Guarded oscillating
saws, by dening the inferior mandible border
and marking the osteotomy line, reduce the risk
of nerve injury. These saws also allow for uniform osteotomies and can correct preexisting
mandible asymmetries.
During genioplasty, the nal chin position
should be evaluated in relation to the entire face,
taking into account intraoperative soft-tissue
swelling. Pre-bent plates offer a guide for precise
anteroposterior chin repositioning, while doublebladed reciprocating saws ensure parallel and
S. Park
accurate osteotomies in procedures like vertical
shortening or narrowing genioplasty.
References
1. Lee TS.Standardization of surgical techniques used
in facial bone contouring. J Plast Reconstr Aesthet
Surg. 2015;68:1694–700.
2. Morris DE, Moaveni Z, Lo LJ.Aesthetic facial skeletal contouring in the Asian patient. Clin Plast Surg.
2007;34:547–56.
3. Chen T, Hsu Y, Li J, etal. Correction of zygoma and
zygomatic arch protrusion in East Asian individuals.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod.
2011;112:307–14.
4. Mu X. Experience in East Asian facial recontouring: reduction malarplasty and mandibular reshaping.
Arch Facial Plast Surg. 2010;12:222–9.
5. Hong SE, Liu SY, Kim JT, Lee JH.Intraoral zygoma
reduction using L-shaped osteotomy. J Craniofac
Surg. 2014;25:758–61.
6. Ma YQ, Zhu SS, Li JH, et al. Reduction malarplasty using an L-shaped osteotomy through intraoral and sideburns incisions. Aesth Plast Surg.
2011;35:237–41.
7. Kook MS, Jung S, Park HJ, Ryu SY, Oh HK.Reduction
malarplasty using modied L-shaped osteotomy. J
Oral Maxillofac Surg. 2012;70:e87–91.
8. Wang T, Gui L, Tang X, etal. Reduction malarplasty
with a new L-shaped osteotomy through an intraoral
approach: retrospective study of 418 cases. Plast
Reconstr Surg. 2009;124:1245–53.
9. Satoh K, Mitsukawa N. Mandibular marginal contouring in oriental aesthetic surgery: rened surgical
concept and operative procedure. Ann Plast Surg.
2014;72:498–502.
10. Khadka A, Hsu Y, Hu J, etal. Clinical observations
of correction of square jaw in East Asian individuals.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod.
2011;111:428–34.
11. Ying B, Wu S, Yan S, Hu J.Intraoral multistage mandibular angle ostectomy: 10 years’ experience in
mandibular contouring in Asians. J Craniofac Surg.
2011;22:230–2.
12. 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;133:274e–82e. discussion 283e.
13. Lee TS, Kim HY, Kim T, Lee JH, Park S.Importance
of the chin in achieving a feminine lower face: narrowing the chin by the “mini V-line” surgery. J Craniofac
Surg. 2014;25:2180–3.
14. Stanton DC. Genioplasty. Facial Plast Surg.
2003;19:75–86.
15. Ward JL, Garri JI, Wolfe SA. The osseous genioplasty. Clin Plast Surg. 2007;34:485–500.
t.me/Dr_Mouayyad_AlbtousH
4 Customized Instruments forFacial Bone Contouring Surgery
25
16. Hoenig JF.Sliding osteotomy genioplasty for facial
aesthetic balance: 10 years of experience. Aesth Plast
Surg. 2007;31:384–91.
17. 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.
18. Kang M.Incidence of complications associated with
mandibuloplasty: a review of 588 cases over 5 years.
Plast Reconstr Surg Glob Open. 2014;2:e139.
19. Han K, Kim J.Reduction mandibuloplasty: ostectomy
of the lateral cortex around the mandibular angle. J
Craniofac Surg. 2001;12:314–25.
20. Cho IG, Chung JY, Lee JW, etal. Anatomical study
of the mandibular angle and body in wide mandibular
angle cases. Aesth Plast Surg. 2014;38:933–40.
21. Hsu YC, Li J, Hu J, etal. Correction of square jaw
with low angles using mandibular “V-line” ostec-
tomy combined with outer cortex ostectomy. Oral
Surg Oral Med Oral Pathol Oral Radiol Endod.
2010;109:197–202.
22. Guyuron B, Raszewski RL.A critical comparison of
osteoplastic and alloplastic augmentation genioplasty.
Aesth Plast Surg. 1990;14:199–206.
23. Chen T, Khadka A, Hsu Y, etal. How to achieve a balanced and delicate lower third of the face in orientals
by mandibular contouring. J Plast Reconstr Aesthet
Surg. 2013;66:47–56.
24. Baek RM, Han SB, Baek SM. Surgical correction of the face with the square jaw and weak chin:
angle-to-chin bone transfer. Plast Reconstr Surg.
2001;108:225–31.
25. Li J, Hsu Y, Khadka A, etal. Contouring of a square jaw
on a short face by narrowing and sliding genioplasty
combined with mandibular outer cortex ostectomy in
orientals. Plast Reconstr Surg. 2011;127:2083–92.
t.me/Dr_Mouayyad_AlbtousH
Part II
Lower Face
t.me/Dr_Mouayyad_AlbtousH
The Comprehensive Aesthetic
Analysis forLower Face
SanghoonPark
5
5.1 Pearls
1. The width of the face’s lower third is signicantly inuenced by the mandible’s width,
which is itself encased by muscles and subcutaneous fat tissues. Beyond the mandibular
width, the chin also plays a crucial role in
delineating the facial shape, underscoring the
importance of a comprehensive understanding
of lower facial types for an exhaustive
analysis.
2. Clinical assessments typically offer explicit
cues for diagnosis, including central symmetry and the contour of the lateral face, in conjunction with the chin’s shape and height.
3. The posteroanterior (PA) cephalogram facilitates the evaluation of mandibular angle protrusion or aring, along with symmetry, chin
deviation, and shape. While the PA cephalogram is instrumental in analyzing skeletal
transverse discrepancies and asymmetry, it is
less effective in assessing vertical
dimensions.
4. The lateral cephalogram is employed to examine facial vertical proportions, the anteriorposterior positioning of the chin, the
mandibular plane, and the gonial angle.
S. Park (*)
Center for Facial Bone Surgery, Department of
Plastic Surgery, ID Hospital, Seoul, South Korea
e-mail: spark@idhospital.com
5. Screening for abnormal skeletal relationships
between the maxilla and mandible, alongside
dental occlusion, is essential to identify the
limitation of facial bone contouring surgery.
6. Ideal facial shapes vary signicantly based on
individual preferences, as well as ethnic and
cultural backgrounds. During consultations
with patients from diverse national or ethnic
origins, it’s crucial to attentively consider
their ideal or preferred facial shapes.
5.2 Introduction
Facial impression is largely shaped by the outer
contour of face and convexity of its constituting
parts. Anthropological studies reveal signicant
anthropometric differences among various ethnic
groups in terms of facial contour. For instance,
Koreans tend to have a more developed lower
face compared to Caucasians. This difference is
quantiable: the average bigonial distance of
Caucasian women is between 105 and 109mm,
while in Korean women, it’s typically between
118 and 125mm [1, 2].
The lower third of the face’s width is determined by the mandible’s width, surrounded by
muscles and subcutaneous fat tissues. Notably, in
Asians, a prominent mandibular angle is often
due to the lateral protrusion of the mandibular
angle, rather than soft tissue factors like a hypertrophied masseter muscle [3–5].
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024
S. Park (ed.), Facial Bone Contouring Surgery, https://doi.org/10.1007/978-981-97-4992-8_5
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29
30
abc
S. Park
Fig. 5.1 Evolution of mandible reduction surgery.
Mandible reduction surgery has evolved from (a) simple
resection of the angular portion to (b) contouring of the
total mandible shape as the desire for a slim and small
face has increased. Recently, (c) V-line surgery not only
In addition to mandibular width, chin plays
an important role in dening facial shape, necessitating a thorough understanding of lower
facial types for comprehensive analysis. We
classify the shape of the lower face based on the
chin’s shape.
A thorough understanding of facial shape is
narrows the width of the mandible and contours the jawline but also reduces the size and controls the position of
the chin was introduced to achieve a slim and oval-shaped
jaw
Assessing bony age is pre-requisite, especially
if there’s uncertainty about the bone’s growth
stage. Preoperative assessments include blood
tests, urine analysis, heart exams, chest X-rays,
and a consultation with an anesthesiologist.
Current medications taken by the patient should
also be reviewed and documented.
critical in formulating treatment plans in practice,
which is crucial for achieving aesthetically pleasing results. Mandible reduction has been evolved
5.3.2 Clinical Evaluation
from simple angle redcution to V-line surgery
and choice of proper technique is critical for satisfactory outcome [6–14] (Fig.5.1).
Clinical ndings often provide clear indications
for diagnosis. This comprehensive consultation
and assessment process ensures a tailored
approach to each patient, considering both physi-
5.3 Patient Consultation
cal features and personal expectations.
andAssessment
1. Central Symmetry: The rst step in evalua-
5.3.1 Patient Selection
andConsultation
Patient’s decision to undergo surgery requires a
careful assessment by the surgeon, who must
fully understand the reasons behind the patient’s
choice. It’s crucial to manage and temper unrealistic expectations. For instance, patients with
thick and abundant facial soft tissue may not
achieve the expected results despite successful
bony reduction. Understanding ethnic differences
in expectations is particularly important in
regions where certain ethnic groups are in the
minority. Decisions made in haste or on impulse
should be reconsidered, as bone resection leads
to permanent changes.
tion is assessing central symmetry. A virtual
midline connecting the intercanthal midpoint,
nose, mid-lips, and chin point is drawn and
analyzed.
2. Lateral Face Contour: The lateral contour of
the face is examined next. This includes evaluating the degree of mandibular protrusion,
asymmetry, hypertrophy of the masseter muscle, and the amount of subcutaneous fat. The
shape and width of the lower face in the frontal view are categorized as shown in Fig.5.2
[15, 16]. The extent of the masseter muscle’s
hypertrophy can be assessed by palpating the
tightened and relaxed states of the jaw.
Hyperostosis, predominantly around the mandible angle, is identied in radiologic studies.
t.me/Dr_Mouayyad_AlbtousH
5 The Comprehensive Aesthetic Analysis forLower Face
31
Fig. 5.2 Classication of mandibular shape and the
patient’s preference of mandibular shape. The chin should
be designed based on individual needs and demands. For
this, the patient can freely compare the shapes of the mandible, especially chin and consult with the surgeon in
detail
Fig. 5.3 Analyzing skeletal asymmetry and facial proportions in frontal plane analysis. With the use of reliable
vertical baseline (a vertical line that is connected to the
chin, which starts from crista galli (Cg) and crossing
ANS) and horizontal reference lines (Z plane, ZA plane, J
plane, a line connecting the left and right antegonial
notch, a parallel line to Z plane at the level of menton),
t.me/Dr_Mouayyad_AlbtousH
degree of parallel of each of the horizon and symmetry of
the facial structure can be assessed. The face is divided
into thirds by horizontal lines drawn adjacent to the menton (Me), the nasal base, the brows (glabella, supraorbital
notch level), and the hairline (Tr). The lower third is further divided into an upper third and lower two-thirds by a
line drawn through oral commissures
32
S. Park
The bigonial width typically accounts for
about 70% of the bizygomatic width (Fig.5.3),
and the bizygomatic width is approximately
75% of the facial height.
3. Chin Shape and Central Vertical Height:
The evaluation of the chin involves assessing
its shape and central vertical height.
• Total Facial Height: Facial height, from
trichion to menton, is divided into upper
facial height (trichion–glabella), midfacial
height (glabella–subnasale), and lower
facial height (subnasale–menton). The
ideal ratio for Asian women is 1:1:0.8 to
1.0, although there’s a trend toward a lower
facial height of 1:1:0.8.
• Lower Facial Height Analysis: Normally,
the ratio between the upper lip length (from
subnasale to stomion) and chin length
(from stomion to menton) is 1:2.
5.3.3 Radiologic Evaluation
Radiologic evaluation is an essential part of preoperative planning in facial bone surgery. The
author routinely acquires a comprehensive set of
radiologic images for each patient, which
includes panoramic views, skull lateral views, PA
cephalograms, and 3D CT images. In addition to
these radiographic examinations, photographs
from frontal, lateral, oblique, and basal views are
taken using standardized techniques. These
images and radiographs are crucial for detailed
aesthetic analysis and form the basis of accurate
preoperative planning.
5.3.3.1 Frontal Plane Analysis
In the PA cephalogram, the extent of protrusion or
aring of the mandible angle and the symmetry,
the deviation, and shape of the chin are assessed.
Although the PA cephalogram is valuable for analyzing skeletal transverse discrepancy and asymmetry, it has limitations in vertical assessments.
a. Chin Shape and Position: Evaluation
includes determining the amount of narrow-
ing, vertical adjustment and midline shift/
correction of the chin if necessary.
b. Angle Shape: It is found that in two-thirds of
cases, there is a mild to moderate increase in
bigonial distance due to lateral aring of the
mandible angle. The remaining one-third
often shows total mandibular hypertrophy,
leading to an accentuated square contour of
the entire lower face.
c. Mandible Body Line: The panoramic view
is particularly useful in assessing the convexity of the mandible’s body and the path of the
inferior alveolar nerve, aiding in determining
the amount and line of the mandibular ostectomy (Fig.5.4).
5.3.3.2 Sagittal Plane Analysis
The lateral cephalogram is used to evaluate the
facial vertical proportion, anterior-posterior position of the chin, the mandibular plane, and the
gonial angle.
a. The chin’s length should be less than twice
the upper maxillary length and less than twothirds of the midface’s length.
b. The anterior-posterior position of the pogo-
nion (Po) is established using Ricketts line
(Fig.5.5).
c. The ideal MP–SN angle ranges between 25°
and 35°.
d. The gonial angle should ideally be within
115° and 125°
After evaluating the balance between the
upper and midface, decisions are made regarding
the necessary advancement or retrusion (setback)
of the mandible in the anterior-posterior
direction.
5.3.3.3 Transverse Plane Analysis
A 3D CT scan and the cervical vertex view is
helpful in identifying the transverse shape of the
mandible.
a. The angle of divergence and the convexity of
the mandible are observed. In cases where
the angle is inwardly curled with a convex
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