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SKELETAL DEFICIENCY
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Craniofacial deformities that are disfiguring and are of functional consequence
to vision, breathing, and mastication usually require skeletal osteotomies and
rearrangement as treatment. Less severe midface and mandibular hypoplasia are common facial skeletal variants. In patients with these morphologies,
occlusion is normal or has been compensated by orthodontics. These patients
have neither respiratory nor ocular compromise. In skeletally deficient patients
whose occlusion is normal or has been previously normalized by orthodontics,
skeletal repositioning would necessitate additional orthodontic tooth movement. Such a treatment plan is time-consuming, costly, and potentially morbid. It is, therefore, appealing to few patients. In these patients, the appearance
of skeletal osteotomies and rearrangements can be simulated through the use
of facial implants. Diagrammatic representations of how implant surgery can
mimic the appearance of skeletal osteotomies are shown in Figs. 1.3 and 1.4.
Skeletal deciency
Fig. 1.3 Diagrams show how multiple
implant augmentation of the midface
skeleton can simulate the visual
appearance of Le Fort III osteotomy and
advancement without altering dental
occlusion. (A) Illustration of midface
concavity and class III malocclusion. Dotted
line shows potential lines of osteotomy.
Arrow shows anticipated advancement.
(B) Osteotomy and advancement at the Le
Fort III level provides midface projection
and class I occlusion. Note change in soft
tissue prole. (C) Illustration of corrected
class I skeletal occlusion after orthodontic
tooth movement. (D) Multiple implants
augmented the midface skeleton whose
occlusion was corrected by orthodontia as
shown in (C). The implants project the soft
tissue envelope to mimic the contour of the
soft tissue envelope of Le Fort III skeletal
osteotomy and advancement.
A
C
B
5
D
Chapter 1 Indications for facial implants
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A
Fig. 1.4 Diagrams show how implant
augmentation of the mandible can
simulate the visual appearance of
sagittal and horizontal osteotomy with
advancement without altering dental
occlusion. (A) Mandibular deciency
with class II occlusion. Dotted line shows
potential lines of osteotomy. Arrows show
anticipated advancement. (B) After sagittal
split osteotomy with horizontal osteotomy
advancement of the chin to increase chin
projection. Note that the occlusion has
been corrected from class II to class I. Note
change in soft tissue prole. (C) Mandibular
deciency after corrected class I occlusion.
(D) The skeletal deciency of mandibular
deciency has been augmented with
implants. Note that the class I occlusion is
unchanged. Also note the change in soft
tissue prole. Notice the absence of border
regularities that are inherent with skeletal
osteotomies.
B
C
6
D
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.
A
C
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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.
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