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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_537_Библиотеки_им_академика_М_И_Перельмана
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interests in clinical procedural research, healthcare business and
administration, and provide equitable healthcare for marginalized patients
throughout the rest of her career.
Emre Tokgöz completed two Ph.D. degrees, one in Mathematics and
another one in Industrial Engineering, at the University of Oklahoma along
with a master’s degree in Computer Science and two master’s degrees in
Mathematics. Due to his interest in biomedical engineering applications of
mathematics and engineering, he pursued an online biomedical engineering
master’s degree for professionals at Johns Hopkins University. His other
research interests include nonlinear optimization, game theory,
deep/machine learning, financial engineering, facility allocation problems,
vehicle routing problems, systems’ design and improvement, network
theory and analysis, inventory systems, and Riemannian geometry.
1 Introduction
In recent years, there has been rapid growth in the field of plastic surgery,
especially regarding the reconstruction of craniofacial injuries secondary to
trauma, burns, or cancer removal. These advancements have allowed for
improved patient safety and surgical precision, while minimizing the
resulting deformity and aesthetic changes. Facial plastic surgeons
specializing in reconstruction are trained in these surgical techniques and
may assist with acute repair of severe injury or delayed reconstruction of
resulting defects after patients are stabilized. Depending on the patient age,
gender, or occupation, among other factors, the presentation and etiology of
craniofacial trauma tends to vary. Younger patients often present with
trauma related to violence or road accidents, while elderly individuals
frequently experience isolated fall-related defects. The etiology of
traumatic, burn- or cancer-related injury is further discussed in the next
section and throughout the chapter, in addition to the different surgical
options for reconstruction and timing of procedures [1–6]. The structure of
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the outcomes we present in this work is similar to those presented in [165–
200].
2 Etiology
2.1 Burns and Trauma
Soft tissue injuries vary in presentation, with some patients sustaining one
isolated injury and others multiple severe lacerations concurrent with
craniofacial fractures and severe internal injury. Elderly individuals and
young children most commonly present with isolated soft tissue injuries
secondary to slips and falls [1–3], while road accidents and assault have
been documented more frequently in patients between the ages of 15 and 50
[4–6].
Burn injuries are attributed to a variety of causes, although most of them
are related to thermal exposure. Chemical, electrical, and radiation-induced
injury occur much less frequently, and the latter rarely presents with
extensive injury [12]. Most commonly, burn-related injuries occur with
workplace accidents, use of open flames while cooking, and hot water
exposure. Hot water-induced scald burns are more frequently documented
in younger children (less than 5years old) and the elderly. In lower income
countries, it is more common to cook on an open flame, thus increasing the
risk of cooking-related thermal injury in women and children [8–10].
Assessment of burn injuries over the years shows a downward trend in
severity, mortality, and incidence. It is estimated that nearly two in three
burns are associated with facial injury, most of which are thermal in origin
[7]. Common causes of facial burn injuries include fireworks (face, eyes)
and electrical burns (mouth). The latter is more common in male children
and can be attributed to electrical outlets, wires, or extension cords [13–15].
While the percentage of burn injuries related to assault, abuse, or selfharm is low (1–2%), providers should be on the lookout for warning signs
especially with pediatric and adolescent patients [2, 11]. These include
pattern burn marks (such as from cigarettes or kitchen utensils), water lines
on the skin (scald burns), and doughnut-shaped burns (usually on the
buttocks). In these patients, a thorough history should be taken to alert
providers of inconsistencies, and special consideration should be given to
the face [17].
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Patients with traumatic injuries are treated depending on the underlying
cause, highlighting the importance of understanding the variable etiology
and role of gender, socioeconomic factors, and occupation [16].
2.2 Skin Cancer
The most diagnosed cancer in the United States is nonmelanoma skin
cancer (NMSC), which occurs frequently in the head and neck. It is
estimated that nearly 1 in 5 individuals will develop skin cancer, and this
risk is increased with frequent sun exposure and/or lack of adequate UVR
protection [17, 18]. Cutaneous squamous cell carcinomas (cSCCs) and
basal cell carcinomas (BCCs) are attributed to the majority of NMSCs,
although there are rarer varieties including Kaposi sarcoma, primary
cutaneous B-cell lymphoma, and Merkel cell carcinoma, among others [19].
Malignant melanomas tend to be more lethal compared with NMSC
subtypes, although the latter is associated with damaging implications such
as disfigurement, loss of function, and morbidity [20–22].
Risk factors for development of malignant skin neoplasms include
repeated and/or childhood sun exposure, increased age, being male,
fair/freckled/easily burned skin, and lighter natural hair (red, blond) or eye
color (blue). SCCs especially are increased in immunosuppressed patients,
as well as individuals with scarring dermatosis, HPV infection, exposure to
ionizing radiation, and tobacco use [23–25].
Repeated or early sun exposure is the primary risk factor for the
development of cutaneous malignant neoplasms via UVR-induced DNA
damage to exposed keratinocytes. In addition to the direct damage, there are
indirect insults to the DNA via UV-induced immunosuppression and
production of free radicals [26]. SCCs develop most frequently after
continued, long-term UVR exposure, while cBCCs are more commonly
induced by intermittent sun exposure [18].
3 Review of Reconstructive Techniques
3.1 Soft Tissue Reconstruction
Reconstructive surgeons generally utilize the least invasive option to repair
the soft tissues of the face whenever possible, as indicated by the
reconstructive ladder. Since its development, advancements in the medical
field have led to creation of the modified reconstructive ladder, which
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incorporates vascular composite transplantation (face transplant) [27]. The
field of reconstructive surgery continues to advance, and additional
guidelines for soft tissue repair have been suggested as shown in Fig. 1.
Fig. 1 The reconstructive grid developed by Mohapatra et al., which highlights the increasing
options available to patients [28]
Extensive damage to the facial soft tissues often requires variable
approaches to care, and the use of a “reconstructive elevator” has been
established, in which minimally invasive options are surpassed in favor of
free tissue transfers. Free tissue transfers have a higher survival rate in the
head and neck as a result of the high vascularization, and they are often the
only option for patients with severe, extensive injuries [29]. The different
options and general indications are discussed throughout this section, with
respect to facial reconstruction.
When primary closure or healing by secondary intention is not possible,
free tissue is harvested from a donor site and grafted at the site of injury,
where it relies on the existing vasculature. This practice is commonly
referred to as skin grafting, and there are many varieties of grafts used for
reconstruction of soft tissue defects. Full-thickness skin grafts (FTSGs)
contain dermal and epidermal tissue, while partial or split-thickness skin
grafts (PTSGs/STSGs) are composed of epidermis and partial dermal layers
[4]. Composite grafts or cartilage grafts contain cartilaginous tissue, which
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is well utilized in the repair of soft tissue losses in the nose or eyelid [30,
31].
There are various materials used for skin grafting, which are categorized
based on the organism from which they are harvested [32–35]:
Autografts: harvested from the patient, allow for permanent healing
Allografts: harvested from cadaveric donor sites, used as a biologic
dressing to prepare the patient for autografting
Xenografts: harvested from different species (usually porcine), used as a
temporary dressing
Other options are available, including skin substitutes such as cultured
epidermal autografts (CEAs). The patient’s skin is obtained via fullthickness biopsy, and the harvested keratinocytes are grown and expanded
into a new “epidermis.” It should be noted that this option is more fragile
and requires longer periods of care during recovery to ensure adequate
healing. Dermal substitutes include Alloderm, which contains a cadavericderived matrix of dermal glycosaminoglycans and collagen, and Integra,
composed of bovine collagen and glycosaminoglycans. The latter is used to
reduce the size of initial injury, allowing for smaller graft or flap placement
[36–38].
Skin grafts are removed with a dermatome, and generally require
preparation before they are attached at the recipient site. The subcutaneous
fat is removed, and the tissues are put through a meshing device, which
punctures the graft in a 1:1 or 3:1 ratio to allow for stretching and improved
wound coverage [39]. In cases of facial soft tissue injuries greater than
3cm, sheet grafts (unmeshed grafts) are used to reduce contracture and
provide a more aesthetic outcome [31].
Flaps are soft tissues which are locally or distally excised from a
preplanned donor site with their respective vasculature to allow for tissue
perfusion and survival. Primary wound closure and/or grafts are generally
the best options whenever possible, although some patients have large
tissue losses which are not conducive to this approach. Various indications
for such complex wound closure include traumatic injury, neoplasm
removal, and congenital defects. Flaps are well utilized in these cases to
provide soft tissue coverage and minimize resultant aesthetic deformities
[40].
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There are a variety of ways in which flaps can be categorized, the first
of which is based upon blood supply [41, 42]:
Axial flaps: Tissues are excised with their respective vasculature (artery
and vein), which runs along the longitudinal axis of the flap.
Random pattern flaps: Donated tissues are perfused via small nonspecific
vessels in the subcutaneous plexus.
Generally, it is recommended to use axial flaps with a single angiosome
(region of soft tissue supplied by a single artery) to allow for optimal
survival. If larger tissues are needed from the donor region, surgeons can
“delay” the flap by incising around the borders and lifting the soft tissues
away from the donor site while maintaining the attachment. Delaying flaps
before transfer allows for opening of smaller surrounding vessels (choke
vessels) and improved tissue perfusion [41]. Random pattern flaps require
additional caution, as their blood supply is more delicate and subject to
damage with torsion. These should be kept at a length-to-width ratio of 3:1
to maintain adequate tissue perfusion [42] (Fig. 2).
Fig. 2 Random pattern (a), axial pattern (b), free flap (c), and perforator flaps (d) [43]
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Flaps may additionally be categorized by their tissue composition.
Tissue loss secondary to trauma, cancer, or congenital defects should be
replaced with similar tissues (e.g., lost bone replaced with osseocutaneous
flaps). Smaller flaps are used for minimal focal defects, including
cutaneous, mucosal, osseous, muscle, and fascia-only flaps. When the
patient has undergone extensive injury with damage to multiple tissue
layers, composite reconstruction is usually indicated [44].
Composite flaps contain multiple tissue types and can be used to replace
large areas with significant loss. The variations include fasciocutaneous
(fascia and skin), myocutaneous (muscle, fascia, and skin), and
osteocutaneous (bone and superficial soft tissues). When the entire face is
damaged, patients may be indicated for human composite tissue allograft
transfer, also referred to as a face transplant [44].
Free flaps, or microvascular flaps, are transferred from donor sites distal
to the injury for the repair of extensive, large deficits. These tend to contain
multiple tissue types (composite) and should be axial in design, and include
[45]:
Anterolateral thigh flap
Iliac crest flap
Gracilis flap
Regional flaps are partially removed from a nearby donor site but
remain attached to some extent and can be used to repair larger or smaller
injuries. These are generally axial in design, although they tend to have a
variable composition and may contain one tissue type or multiple. These
include [45]:
Paramedian forehead flap
Temporoparietal fascia flap
Gracilis flap
Local flaps are directly adjacent to the injury and usually contain
mucosal or cutaneous superficial tissues with random pattern blood supply.
Additional caution should be taken with local flaps to place the closure in
an aesthetic subunit boundary (hairline, nasolabial folds, or rhytids).
Regional or local flaps may be advanced, rotated, transposed, or
interpolated above/below normal tissue, depending on the extent and/or
relative location of injury [46] (Fig. 3).
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Fig. 3 The V-Y advancement and rotation flaps are well utilized when there is enough local tissue
available to allow for defect coverage [47]
3.2 Osseous Reconstruction
The facial skeleton is a complex structure composed of four unpaired and
five bilaterally paired bones. Functionally, these bones are grouped into
four horizontally oriented and four vertically oriented pairs of buttresses
(struts). The bony struts of the facial skeleton comprise the strongest
osseous framework of the craniofacial tissues, and fractures at these struts
frequently require surgical fixation and stabilization [48].
More commonly, the bones of the craniofacial skeleton are organized
into upper, middle, and lower thirds, which allow for more straightforward
surgical assessment and planning [49] (Fig. 4).
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Fig. 4 (a) The application of the buttress classification system on a 3D CT of the skull. The four
horizontal pairs include the upper (yellow) and lower (orange) transverse maxillary struts, as well as
the upper (brown) and lower (green horizontal) transverse mandibular struts. Medial (red), lateral
(blue), and posterior (pink) maxillary struts, as well as the posterior mandibular struts (green vertical)
make up the vertical pairs. (b) The facial thirds classification system, with the orange line identifying
lower margins of the upper third and the yellow line containing the lower third [49]
Depending on the location and severity of these fractures, damage to the
orbit or underlying neurovascular structures may have occurred and should
be recognized as soon as possible. CT imaging is well utilized to assess for
rupture of the ocular globe, although the presence of ocular neuropathy
secondary to traumatic injury is better detected with MRI [50, 51].
After the structural integrity of the bone cortex is disrupted, secondary
healing will commence to repair the fractured tissues. The general timeline
is detailed below, although there is some overlap between the healing stages
[52]:
Days 1–5: Hematoma formation
Days 5–11: Fibrocartilaginous callus formation
Days 11–28: Bony callus formation
Day 18-variable (months/years): Bone remodeling
Alternatively, primary bone healing allows for reformation of the
osseous cortex without callus formation. The results of secondary healing
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can be aesthetically devastating if the bone heals in the wrong place, and
primary bone healing via reduction and fixation should be implemented
whenever possible [52]. Facial fractures without bone loss can be repaired
with open reduction internal fixation (ORIF), followed by bridging of large
bony gaps with bone grafts or temporary plating [53].
3.2.1 Open Reduction Internal Fixation (ORIF)
Open reduction is performed through an incision to gain full visibility of the
fracture site. This is commonly utilized with facial fractures due to the
complicated nature of these injuries. The edges of fractured bone are moved
into close apposition, which reduces callus formation and accumulation of
granulation tissue. After the bones are realigned, osteoclasts and osteoblasts
work to remove damaged bone and produce new tissues, respectively [54,
55].
Internal fixation is performed to maintain the close apposition of
fractured bone edges, using titanium plates and screws for a secure
attachment [52, 56] (Fig. 5).
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