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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_660_Библиотеки_им_академика_М_И_Перельмана
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Fig. 1.5 shows a patient with corrected occlusion who underwent multiple
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implant correction of her midface and mandibular deficiencies.
Skeletal deciency
A
Fig. 1.5 A 46-year-old woman had undergone facelift, blepharoplasty, and browlift in the past. She underwent
infraorbital rim, paranasal, malar, mandible, and chin augmentation with lengthening. The brow was lowered
and a midface lift was also performed. (A) Preoperative frontal view. (B) Postoperative frontal view.
B
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Chapter 1 Indications for facial implants
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CONGENITAL DEFORMITIES
Patients with craniofacial syndrome microforms and those with previously
corrected syndromic deficiencies can often benefit from implant augmentation. Fig. 1.6 shows a patient with Treacher–Collins syndrome whose orbito-
malar area was reconstructed with porous polyethylene implants. Fig. 1.7
shows a 30-year-old woman with Stickler syndrome who had undergone
monobloc facial advancement surgery as a child. Forehead contour and
supraorbital rim–globe relationships were improved with an acrylic onlay
cranioplasty.
Fig. 1.6 A 35-year-old woman with malar
and lateral orbital deciency due to
Treacher–Collins syndrome underwent
reconstruction. Silicone implants placed
during her teens had been removed to
treat infection. Rib grafts had resorbed.
Reconstruction was performed with
custom-carved porous polyethylene
implants. In addition, lateral canthopexies
and a genioplasty were performed.
(A) Preoperative and (B) postoperative
frontal views. (C) Preoperative and (D)
postoperative lateral views 2 years after
surgery.
A
C D
B
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Congenital deformities
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Fig. 1.7 A 30-year-old woman with Stickler syndrome had
undergone monobloc facial advancement surgery as a child.
Forehead contour and supraorbital rim–globe relationships were
improved with an acrylic onlay cranioplasty. A porous polyethylene
implant was used to augment the radix and nasal dorsum. (A)
Preoperative lateral view. (B) Postoperative lateral view 1 year after
surgery.
A
B
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Chapter 1 Indications for facial implants
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POSTTRAUMATIC AND POSTABLATIVE DEFORMITIES
Posttraumatic and postablative deformities may also benefit from alloplastic implant reconstruction. Indications for alloplastic replacement
of the craniofacial skeleton are limited. These areas must be non-loadbearing and protected from sinus exposure. Replacement in load-bearing
areas inevitably leads to micromotion at the implant–bone interface with
bone erosion and subsequent implant extrusion. Implants that are chronically exposed to the sinuses are inevitably contaminated with bacteria
and may be lost to infection. Portions of the cranial vault (Chapter 5) and
internal orbit (Chapter 7) are the areas reliably replaced by alloplastic
implants.
Fig. 1.8 shows the reconstruction of a posttraumatic orbitomalar facial
deformity using alloplastic implants. Fig. 1.9 shows alloplastic implant
reconstruction of a non-load-bearing area of the facial skeleton after tumor
extirpation.
Fig. 1.8 A 32-year-old woman was struck
by an automobile and suered multiple
injuries including a right orbital fracture.
The orbit was not reconstructed acutely
and the patient developed enophthalmos
as well as a loss of malar prominence. At
reconstruction 9 months after injury, the
internal orbit and malar deciency were
reconstructed with porous polyethylene
implants. (A) Preoperative and (B)
postoperative frontal views. (C) Preoperative
and (D) postoperative worm’s eye views.
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A
C
B
D
Skeletal versus soft tissue augmentation
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A
Fig. 1.9 Sequential frontal views (A) preoperatively, (B) 1 year postoperatively, (C) 10 years postoperatively, and (D) 14 years postoperatively
of a woman treated for a chondromyxoid broma of the left zygoma. The patient was treated with radical removal of the involved facial
skeleton and immediate reconstruction with porous polyethylene implants stabilized with plates and screws. Parts A and B from Carr NJ,
Rosenberg AE, Yaremchuk MJ. Chondromyxoid broma of the zygoma. J Craniofac Surg. 1992;3(4):217–222, with permission. Parts C and D
courtesy Dr. Yaremchuk.
B
C
D
SKELETAL VERSUS SOFT TISSUE AUGMENTATION
Plastic surgery’s last decade is notable for its recognition that aging is accompanied by facial soft tissue atrophy. Facial rejuvenation surgery is no longer
one of simple excising and tightening. The value of soft tissue repositioning and augmentation have been recognized and exploited. Unfortunately,
since the ultimate expression of skeletal or soft tissue structure is reflected
on the skin’s surface, some surgeons have used this as a justification for the
equivalence and interchangeability of soft and hard tissue augmentation.
For example, malar skeletal implants are used to restore cheek fullness while
fat grafts are used to create malar skeletal prominence. Up to a millimeter
or so, the visual effect of either augmentation modality may be equivalent,
depending on the thickness of the overlying soft tissue envelope. However,
beyond a minimal augmentation, the visual effects of these modalities are
markedly different. This is easily conceptualized when envisioning large
augmentations. A large implant placed on the malar bone will make the
cheek project more, making the face more defined and angular, therefore
making the face appear thinner and more skeletal. Large implants placed
in patients with thin soft tissue envelopes will become increasingly visible
with aging (Fig. 1.10). With implant selection, the surgeon should remember
that soft tissues change over time, while implants do not. Implanting fat
into the cheeks will also make the cheeks project more; however, the face
will appear increasingly round, and therefore less defined and less angular
(Fig. 1.11).
3
PEARL
Soft tissues change with time,
implants don’t.
Although there is limited
interchangeability between soft
tissue and skeletal augmentation,
they can certainly be complementary.
Many patients can benet from both
volumetric increase in their soft tissue
envelope and an increase in their
skeletal projection.
1,2
PEARL
Soft tissue augmentation and
hard tissue implants are not
interchangeable. They may be
complementary.
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Chapter 1 Indications for facial implants
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A B
Fig. 1.10 A 64-year-old woman had previous
malar implant surgery, upper and lower lid
blepharoplasty as well as rhytidectomy as
rejuvenation procedures in the past. Over
time, the large implant created an overly
prominent skeletal contour.
Fig. 1.11 A 30-year-old woman had undergone fat grafting of the malar midface area. Fat
grafting in this young woman obliterated skeletal denition and distorted cheek contour.
(A) Frontal and (B) oblique view.
REFERENCES
1. Barton Jr FE. Aesthetic surgery of the face and neck. Aesthet Surg J 2009;29(6):449–63.
2. Endara MR, Allred LJ, Han KD, Baker SB. Applications of fat grafting in facial aesthetic skeletal
surgery. Aesthet Surg J 2014;34(3):363–73.
3. Yaremchuk MJ. Commentary on: the role of microfat grafting in facial contouring. Aesthet Surg J
2015;35(7):772–3.
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Chapter 2
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Evaluation and planning for facial
implant surgery
Physical examination is the most important element of preoperative assessment
and planning for both reconstructive and cosmetic procedures. Reviewing photographic images with the patient can be helpful when discussing aesthetic
concerns and goals.
All faces are asymmetric. Asymmetries are usually subtle but, with sufficient
scrutiny, detectable (Fig. 2.1).
Their recognition preoperatively is important to both the surgeon and the
patient. The patient’s asymmetry should be pointed out during the preoperative
consultation so that the patient can anticipate asymmetry in the postoperative
result. Preoperatively, the asymmetries belong to the patient. Postoperatively, if
not identified before the surgery, they are attributed to the surgeon.
As asymmetries become more severe, it is important to recognize that they
are more complex than relative skeletal deficiencies or excesses. Rather, they
reflect three-dimensional differences that are most easily conceptualized as
twists of the facial skeleton.
PEARL
Always describe a patient’s
asymmetry during preoperative
consultation.
A B C
Fig. 2.1 To demonstrate the asymmetry in a “normal” face, a photograph has been manipulated to create three separate images. (A) Frontal
view of 20-year-old woman presenting for rhinoplasty. (B) Composite created by joining right side of face with its mirror image. (C) Composite
created by joining left side of face with its mirror image.
RADIOLOGIC EXAMINATION
Most aesthetic procedures are done without preoperative radiologic assessment. In general, the size and position of the implant are largely aesthetic
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Chapter 2 Evaluation and planning for facial implant surgery
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judgments. Cephalometric X-rays are most often used for planning chin and
mandibular augmentation surgery. These studies define skeletal dimensions and
asymmetries as well as the thickness of the chin pad.
While preoperative radiologic examination is uncommon for purely aesthetic surgery, computed tomographic (CT) evaluation is almost routine for
reconstructive procedures. CT scans provide the ability to view the skeleton
in different planes and, through computer manipulation, in three dimensions.
CT imaging provides digitized information that can be transferred to design
software. CAD/CAM implants provide an increased level of refinement in both
reconstructive and aesthetic applications. This modality has been used since
the 1990s to reconstruct cranial defects. Computer-aided design (CAD) and
computer-aided manufacture (CAM) can be used to create life-sized models for
surgical planning (Fig. 2.2) and implants customized for the needs of the patient
(Fig. 2.3).
The design process can also be conducted virtually as demonstrated in Fig. 2.4.
The CAD/CAM process is the focus of Chapters 14 and 15.
Cone beam CT scans are available in many dental offices. They have the
advantages of less expense and less radiation exposure to the patient. They can
provide three-dimensional images of the facial skeleton and are therefore valuable in planning. Because their field is limited and head-positioning devices
distort the soft tissue envelope, cone beam CT has a limited role in the CAD/
CAM implant process.
Magnetic resonance imaging, invaluable for soft tissue assessment, does not
have a role in skeletal evaluation and implant surgery planning.
Fig. 2.2 CT scan data was used to fabricate a
skull model in planning surgery for a patient
with facial asymmetry.
FACIAL MEASUREMENTS
For most reconstructive problems, surgery is performed to return the involved
area to its original appearance, or, if that is not possible, to one that is symmetric
and accepted as normal. When alloplastic implants are used to make the face
more attractive, the aesthetic goal is more arbitrary. Because implant augmentation of the facial skeleton results in measurable changes in facial dimensions
and proportions, it is intuitively attractive and appropriate to use facial measurements to evaluate the face and to guide surgery.
Mathematical ideals
In his book on Leonardo da Vinci’s anatomical drawings, Martin Clayton
explains how mathematical ideals influenced classical and Renaissance artists in their perception and depiction of the human body.1 The ancient Greeks
observed that musical notes created by strings whose lengths were in simple
numeric ratios were intrinsically pleasing. They extended this concept to spatial intervals and established the concept that harmonic ratios were intrinsically
“right” and thus fundamental to the structure of the universe. In the 1st century
BC, Vitruvius adapted the proportional concept to the human body. He proposed that the body should be divisible into equal parts, and that all of its units
should be expressible in terms of that unit or fractions of the whole. His treatise
De architectura, which describes his proportional system, was one of the few
classical texts that survived to the Renaissance and became highly influential in
the thinking of artists and scholars of that time, including Leonardo da Vinci.
Early in his career, Leonardo adopted many of Vitruvius’ ratios. Most of us
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today associate Leonardo’s anatomic drawings with his rendition of Vitruvius’
A
B
Fig. 2.3 (A) Skull model and (B) with
custom cranial implant obtained from
three-dimensional CT scan data.
Facial measurements
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Fig. 2.4 Computer-aided design (CAD) virtual images of midface
and chin–mandible implants designed for aesthetic skeletal
augmentation. (A) Frontal view and (B) lateral view.
Max
projection
@ 9 mm
A
B
Max projection
@ 8.5 mm
Max projection
@ 5 mm
Max
projection
@ 9 mm
Max projection
@ 6.5 mm
Max anterior
projection
@ 6.5 mm
ideal proportions for the human body (c.1490–92) whereby “the body when
standing with arms stretched fits into a square and, with all limbs splayed, into
a circle centered on the navel” (Fig. 2.5).
Leonardo soon found limitations in the use of proportions to depict the
human form. By 1500 he abandoned the idea of a single canon of ideal proportion to describe the human body. In the winter of 1510 he collaborated with
the Professor of Anatomy at the University of Pavia, Marcantonio della Torre.
This relationship provided Leonardo access to human material allowing him to
depict human structure with great accuracy. As Leonardo learned human anatomy, he realized that the use of ideal proportions thwarted its accurate depiction. He used proportion as a tool to help describe its form and function rather
than as an end to itself.
When the dimensions of normal males and females were evaluated objectively and compared to these artistic ideals, it was found that some theoretic
proportions are one of many variations found in healthy normal individuals, including those determined more attractive than most individuals, and
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Chapter 2 Evaluation and planning for facial implant surgery
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Fig. 2.5 Leonardo da Vinci’s rendition of Vitruvius’ ideal proportions for
the human body (c.1490–92) whereby “the body when standing with arms
stretched ts into a square and, with all limbs splayed, into a circle centered
on the navel.” Leonardo later realized after studying human cadavers that the
human body does not conform to these proportions.
some are never found
2,3
(Fig. 2.6). The neoclassical canons do not allow for
facial dimensions known to differ with sex and age. Most of these canons of
proportion, for example that the width of the upper face is equal to five eye
widths, are interesting but hold for few individuals and cannot be obtained
surgically or, if obtainable, only with extremely sophisticated craniofacial
procedures.
Researchers from various disciplines have emphasized the difficulties
with mathematically defining a beautiful face. For example, the orthodontist
Robert M. Ricketts pointed out that although the ratio phi, equal to 1.1618
and known as the divine proportion, may be seen in many biologic forms and
its approximation may characterize certain relations of the normal human
face, it does not distinguish beautiful from plain.4 The psychologist Nancy
Etcoff analyzed human beauty and its impact on society in a book that is subtitled The Science of Beauty. She also found that the perception of beauty could
not be defined by mathematical formulae. The summary of her analysis of
mathematical ideals to human beauty was, “For scientists in this century, the
key to understanding human beauty is in our biology not in mathematics.”5
Since neither the normal nor the beautiful face can be defined by mathematical ideals, we have found it more useful to use the averaged anthropometric measurements of selected age, sex and ethnicity, rather than neoclassical
canons, to guide our gestalt for the selection of implants for facial skeletal
augmentation.
PEARL
Symmetry is benecial but does not
dene facial beauty.
Facial anthropometrics
The late Leslie Farkas, a medical anthropologist, accumulated large numbers of precise, reproducible surface measurements of various population
groups of both sexes.6 These data define normative values, as well as gender
and ethnic differences in facial measurements and proportions. The anthropometric data used in this book come from measurements made in a large
group of young white North American adult men and women.6 Similar information is available for Asian, African, and certain other ethnic groups.
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Anthropometric landmarks, measurements, and inclinations are useful for
7–9
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