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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_1054_Библиотеки_им_академика_М_И_Перельмана
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B. C. Ashok and D. Sreekumar
9. Agha RA, Fowler AJ, Herlin C, Goodacre TEE, Orgill
DP. Use of autologous fat grafting for breast reconstruction: a systematic review with meta-analysis of
oncological outcomes. J Plast Reconstr Aesthet Surg.
2015 Feb;68(2):143–61.
10. Alao RK, Nassif MO, Al-Hajeili MR.Prophylactic
mastectomy for the prevention of breast cancer: review
of the literature. Avicenna J Med. 2018;8(3):67–77.
11. McAllister P, Teo I, Chin K, Makubate B, Alexander
MD. Bilateral breast reconstruction with abdominal
free aps: a single Centre, single surgeon retrospective review of 55 consecutive patients. Plast Surg Int.
2016;2016:6085624.
12. Taylor EM, Wilkins EG, Pusic AL, Qi J, Kim
HM, Hamill JB, et al. Impact of unilateral versus bilateral breast reconstruction on procedure
choices and outcomes. Plast Reconstr Surg. 2019
Jun;143(6):1159e–68e.
Silicone Gel Breast Implants
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ShaziyaHassanAli andRishikeshParmeshwar
28
28.1 Introduction
Silicone breast implants are well-known devices
for cosmetic breast surgery and have been usedto
achieve breast augmentation for nearly six
decades. They have also been a useful adjunct in
breast reconstruction for nearly as long but the
outcomes from implant based reconstruction
continued to be suboptimal till just overa decade
ago. This improvement in the outcome from
implant based reconstruction was only possible
because of the advent of biological meshes in the
late 90s and early millennium. Breast implants
have nowbecome the commonest form of breast
reconstruction in the western world and theiruse
is on the rise globally. This is primarily because
of the advantage of implant based reconstructions being less invasive, simpler to perform,
have quicker recovery and the improved outcomes it now has to offer. It is important to
emphasize that despite their popularity as a tool
in breast reconstruction they are after all prosthetic devices and are not free from problems.
Hence, it is vitally important for a reconstructive
surgeon to be fully aware of the issues associated
with them to ensure optimal outcomes. This
chapter provides an overview of silicone implants
with special reference to their use in breast
reconstructions.
S. H. Ali · R. Parmeshwar (*)
University Hospitals of Morecambe Bay, Lancaster, UK
28.2 Structure ofSilicone
Implants
Silicone implants as the name suggests use silicone gel enclosed in a shell which again are made
of the same material. While saline implants are
still available, silicone implants areby far the most
commonly used breast implants. Before we discuss the silicone implants, it is important to understand the difference between silica, silicon and
silicone and how are they related to each other.
Silica (as in sand or ina quartz crystal) is silicon dioxide (SiO2) found in abundance in the
earth’s crust. Silicon (as in Silicon Valley), however, is a semi-metallic element and is not found in
its pure elemental form in the nature. It can only be
created by a complex process of heating silica with
carbon in an electric arc furnace separating silicon
from silica. The commonest use of elemental silicon is in semiconductor electronic components.
Silicone (as in breast implants) on the other hand
is an organic polymer of silicon carrying two
methyl groups and linked with oxygen. The polymers are of such silicone molecules hence are
known as poly-dimethyl siloxane (PDS). The
length of these polymers and the cross linking (by
substitution of methyl groups with hydride and
vinyl) of these PDS chains determine the cohesiveness of silicone gel. Shorter chain polymers of
such PDS are in liquid form and are extensively
used in various day to day products such as cosmetics, toiletries, automobile and healthcare
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023
S. V. S. Deo (ed.), Breast Oncoplasty and Reconstruction,
https://doi.org/10.1007/978-981-99-5536-7_28
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S. H. Ali and R. Parmeshwar
industry. They are almost ubiquitous and present
in many of the products we all use in our day-today life. However, longer chain PDS polymers
take the form of gel and when cross-linked become
cohesive, a property which has been utilized in
newer generations of implants to minimize gel diffusion (gel bleed) through the shell and provide
rmer consistency (and in some cases controlled
softer consistency).
The shells of the implants are also PDS derivatives with extremely long chains with heavy
cross linking giving them to a solid form. They
are called elastomers and a typical current generation silicone implant shell will have multiple
layers of elastomer shells compressed into a single shell cover.
28.3 History andEvolution
ofBreast Implants
From the rst ever attempt to add volume to female
breast by Vincent Czerny in 1895 by implanting a
st size lipoma removed from elsewhere from the
patient, surgeons in the rst half of the twentieth
century attempted to implant various objects into
female breasts to augment them with disappointing
to disastrous outcomes [1]. These objects included
animal cartilages, synthetic materials such as glass
balls and sponges to organic material such as parafn. Japanese women during thesecond world-war
were injected with liquid silicone material for breast
augmentation to solicit company of American soldiers. This led to some horric results from inammation, infection, granulomas formation, embolism
and even deaths [2].
Frank Gerow and Thomas Cronin in association
with Dow Corning Company, Texas, engineered the
rst ever silicone breast implant in 1961 and performed the rst breast augmentation in 1962 following an attempt to check its safety on a dog [3].
These rst-generation implants had a thick shell and
dense gel but did not have a natural feel to them.
From the feedback from surgeons, second generation implants were developed with thinner shells
and more uid silicone gel [4]. This unfortunately
resulted in ahigh incidence of ruptures and complications leading to concerns on the safety of these
implants. This led to scores of litigations despite
continued progress in the technology and signi-
cant improvement in the quality of these implants in
the 1970s [5]. In the 1980s third generation implants
were developed with attempts at producing cohesive gel and adding abarrier layer to the shell to
provide strength and minimize leaks and gel bleed
[6]. In the subsequent years, fourth and fth generation implants with varying silicone gel cohesiveness
were introduced. The highly cohesive silicone
breast implants are tear drop shaped or anatomically
shaped with a sloping upper pole and fuller lower
pole. They differ from round shaped implants as the
silicone gel molecules are highly cross-linked facilitating retention of their anatomical form as well as
delivering more rmness [7]. These properties of
the anatomical implants make them more suitable
for post mastectomy breast reconstruction.
Despite these attempts, there was a lack of
robustevidence on the safety of these implants
and as such in 1993, the FDA (Food and Drug
Administration, USA) put a moratorium on the
use of silicone implants and thiswas only lifted
in 2007 following evidence produced by the
implant manufacturers [8]. Their use, however,
continued in the other parts of the world in that
period and has remained a topic of debate. There
have been concerns if silicone implants could
have systemic effects and if they could cause
autoimmune disorders. Despite the developments
in the technology one of the more recent controversies surrounding silicone implants involved
Poly Implant Prothese (PIP implants by a French
company), which were banned in 2011 because
of the concerns around use of poor quality silicone and higher than expected rupture rates [9].
Currently, BIA-ALCL (Breast implant associated anaplastic large cell lymphoma) is at the
heart of silicone implant controversy prompting
the World Health Organization to update lymphoma classication to include BIA ALCL as a
new disease entity [10]. Its incidence is thought
to be anywhere from 1:3000 to 1:60000 [11].
Association of Breast Surgery, UK, advises that
the patients are given a risk of about at least
1:24000 of developing BIA ALCL if they have a
silicone breast implant. The causative factors are
thought to be related to an autoimmune response
initiated by an inammatory reaction to silicone
products and/or certain microbial species specically found in the surface of the implant called
biolms [12].
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211
Biolms have been dened most recently as “a
coherent cluster of bacterial cells (one or several
species) behaving as colonies, embedded in a polymer matrix they produce on the implant surface, and
become tolerant to most antimicrobials and host
defense”. This is in contrast to planktonic (freeoating) bacterial cells which are more amenable
host defence and antimicrobial therapy [13].
Biolms are also known to be associated with grade
3 and 4 capsular contractures in addition to their
possible role in the development of ALCL. These
bacteria are not possible to isolate and grow in conventional culture media and require special culture
methods aided by physical extraction of bacteria
with techniques such as sonication. These longterm implications along with the earlier risk of
infection by colonization of skin bacteria makes it
highly imperative to take all the precaution to minimize contamination of the implant at the time of
insertion. The use of occlusive nipple shields in
nipple sparing mastectomy and use of non-touch
insertion of implants by use of funnel devices preventing any contact with skin may reduce contamination and hence biolm formation [14].
It is now quite important that surgeons using silicone implants are aware of these above- mentioned
issues and incorporate these facts into the discussion and information provision to the patients.
well as reconstructive surgery. However, there are
still implants available which can be lled with
saline following insertion instead of prelled silicone gel. The shells of these saline implants are
made of elastomer layers which again are silicone
derivative. There are also adjustable siliconeimplants
(e.g.,Becker prosthesis ®) with a removable ll tube
and injection port to facilitate adjustment of the central core with saline to achieve the desired volume
after weeks of implantation. This has the benets of
allowing the wound to heal with lesser wound tension before periodic insufations with saline are
done to adjust the volume to adesired size.
Silicone implants are used for cosmetic augmentations, correction of developmental anomalies and also for breast reconstructions. They
come in various shapes, sizes, styles, degree of
gel cohesiveness, shell features and can generally
be classied on the basis of the following
properties:
• Shell surface
• Gel cohesiveness
• Shape
• Style
• Volume adjustability
28.4.1 Shell Surface
28.4 Types ofImplants
Constitutionally, all breast implants are now supposed to have cohesive gels with multi-layered elastomer shells. Fixed volume silicone implants are by
far the commonest types used for both in cosmetic as
Fig. 28.1 A smooth (left) and a textured (right) implant
*
All the images of the implants and tissue expanders used are Mentor® devices (J & J MedTech)
• Smooth
• Textured
Shell surface is quite an important consideration when it comes to making a choice for an
implant. As shown in Fig.28.1, the surface can be
*
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S. H. Ali and R. Parmeshwar
smooth or textured. The texturing can again be
either coarse (macro) or ne (micro). A vast
majority of the surgeons in the UK and Europe
use textured implants. Textured implants are
supposed to reduce the incidence of capsular
contracture. This is based on the studies in the
1980s and 1990s on the incidence of capsular
contracture with smooth and textured implants
[15]. It is proposed that capsular contracture is
related to organised deposition of collagen bres
around the implant surface and their subsequent
shortening. Texturing allows an in-growth of host
tissue into the random crypts of the textures and
disrupts organized collagen formation hence a
reduced incidence of capsular contracture. This
preference of textured implants is, however, now
under scrutiny with the BIA-ALCL association
with silicone implants, which is almost exclusively related to textured implants. There are
some suggestions that they may be more common with macro-texturing with a possible association with the technique used to create the
texturing [16]. Some of the very popular implants
had to stop making their textured implants
because of higher incidence of BIA ALCL with
their products. At the moment both in the Europe
and in America there is no advice against use
of textured implants but the patients must be
informed of this rare but denite association.
It is also worth mentioning that there are other
varieties of implant surfaces such as polyurethane coating. The manufacturers claim that this
coating reduces the chances of capsular contracture but as with many of the implants related
issues there is a relative lack of robust evidence to
support such claims.
28.4.2 Gel Cohesiveness
As discussed in the structure of the implants,
cohesiveness of the gel determines its consistency and also how likely it is to maintain its
shape, resist rippling, minimize gel bleed and
silicone migration if the integrity of the
implant is compromised [17] (Fig. 28.2).
Various manufacturers have their own expressions to indicate low, moderate and highly
cohesive implants. It is up to the surgeons to
consider various factors to make the correct
choice for an individual patient. While
the patient’s preference would play a major
role in choosing the degree of cohesiveness in
cosmetic augmentation, in post mastectomy
breast reconstruction highly cohesive implants
are often preferred over less cohesive gel
implants because of the property of the former
in maintaining its shape.
Fig. 28.2 A cut through the implant demonstrating highly cohesive gel*
ab
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28.4.3 Shape
• Round or dome shape
• Anatomical or tear drop
The shape of the implants need to chosen
carefully by the surgeon both in cosmetic as
well as in a reconstructive surgery. A round
implant will have a circular base and a mound
(Fig.28.3a) with varying projections and cohesiveness while an anatomical implant is of a
shape of a breast or often referred to as tear drop
shaped (Fig.28.3b). The base of these implants
is not circular and needs to be put in the right
orientation with thinnest part superiorly and the
widest to the lower pole. These anatomical
implants have a mark at the lower pole to help
the users. A round implant has the benet of
offering more central projection at the cost of a
natural ptosis, a property often used in the cosmetic augmentation. They also have the benet
of not affecting the shape of the breast/reconstructed breast if they rotate. On the other hand
the anatomical implants will generally have
highly cohesive gel and will be much rmer
than the round implants. Their tear drop shape
makes them a preferred option in breast reconstruction where the skin envelope after mastectomy needs to be lled with implant to achieve
an optimum and aesthetically pleasing breast
shape. They are also used in cosmetic augmen-
tation of breast wherein the individual is looking for a natural looking shape. Anatomical
implants have different widths and heights such
that their maximum projection not centrally
located, hence, if they rotate the shape of the
reconstructed breast changes too [18].
It must be borne in mind that the abovementioned distinctions are a general guide and
not an essential rule. To achieve a good outcome
several other factors such as breast consistency,
overlying skin quality, degree of ptosis, patients’
expectations as well as surgeon’s own experience
and preference play pivotal roles.
28.4.4 Volume
Silicone implants come in a vast array of sizes
described either in volume terms (cc) or in some
cases in weight (gms). This could vary from
100cc to over 800cc. It is quite important that
correct volume and style of implant is chosen
based on the breast dimensions with patient’s
preferences taken into account. There is an association with high implant volume (>450cc) and
high rate of implant losswhen used in a direct to
implant immediate breast reconstruction. Hence,
it is important to be careful when performing a
direct to implant immediate breast reconstruction with a xed implant volume of over 450–
500cc. The weight of the implant puts pressure
Fig. 28.3 (a) A round implant (b) An anatomical implant*
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S. H. Ali and R. Parmeshwar
on the skin envelope and the suture lines; hence
encouraging a compromised healing process,
skin necrosis and infection. In such scenarios
wherein a higher volume implant is required, it
is prudent to use an adjustable implant such as a
Becker prosthesis, which can be implanted in a
partially collapsed state, allow the initial healing
to take place and adjustment of the volume
subsequently.
28.4.5 Style
Style of an implant refers to the various combinations of width, height and projection of an anatomical implant or a tissue expander. These styles
are named differently by different companies and
a surgeon needs to understand what these styles
stand for as they inuence signicantly the outcome both in cosmetic as well as in the reconstructive surgery. Styles are simply a reection of
the huge variation in the key parameters of height,
width and projection of the breasts in need for
reconstruction or augmentation. It is a usual practice for the width to be the key dimension for
which a style of height (low, medium or tall) and
projection (low, moderate or a high prole) can
be chosen from a catalogue. The way these
implants are named according to their style vary
from make to make and a style represents a particular combination of the key dimensions so that
they can be ordered on the basis of volume and
style rather needing to refer to width, height and
projection.
28.4.6 Adjustability
Fixed Volume
Adjustable
By far the commonest type of breast implants
are of xed volume. In most clinical scenarios
they are the preferred ones. However, in some
clinical situations it is desirable to have an
implant which has some degree of adjustability to
achieve a better symmetry in cases of breast
reconstructions. Itis also sometimes imperative
to use adjustable implants when a large volume
implant is needed but a xed volume implant
increases risk of implant loss as mentioned earlier. Becker prosthesis® is one such device
(Fig.28.4). It has a varying proportion of silicone
gel in an outer pocket (Becker 25/35/50, the numbers indicating the proportion of silicone making
the total volume of the implant) and the central
separate pocket which can be lled with saline to
adjust the total device volume. These adjustable
implants come with an attached ll tube and a
port; the latter gets sited in a sub-dermal position
and can be used to inject saline to increase the
volume of the device. Once the nal adjustment
is achieved, the port and the ll tube are removed
under local anaesthetic.
Fig. 28.4 A Becker 35 prosthesis® with ll tube and port*
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a
b
Fig. 28.5 (a) A tissue expander within an integrated port (b) A tissue expander with a ll tube and port*
215
28.4.7 Tissue Expanders
Any discussion of breast implants would be
incomplete without a reference to tissue expanders. Tissue expanders are expandable devices
made of silicone elastomers. They can be used in
two-stage breast reconstructions where a direct to
implant technique is either not desirable (high
risk patients such as smokers, diabetics, signicant co-morbidities). In some cases they are the
preferred technique of the reconstructive surgeons. Since the advent of biological meshes,
incidence of two-stage reconstructions has gone
down signicantly but they still remain as auseful options. In a partly collapsed state these
devices can be introduced either in a total subpectoral position (classic two-stage sub-pectoral
implantbased reconstruction) or less commonly
in a pre-pectoral position, and gradually expanded
over the subsequent weeks to achieve desired
volume and then replaced with a xed volume
implant. These tissue expanders come with either
a separate port (Fig.28.5a) or an integrated port
(Fig.28.5b). The ports of these devices are also
made from silicone. Saline is injected through
these ports. The needle tracks self-seal and prevent leaking back of injected saline.
28.5 Patient Selection forImplant
Based Reconstruction
Patient selection is the key to a successful
breast reconstruction. It is also a crucial factor
in minimizing complications. It is quite important to bear in mind that implant based reconstructions are generally associated with
signicant readmission and reoperation rates in
the early postoperative period and a poor selection of patients can make this a truly disappointing experience, both for the patient as well
as the clinical team. As such, patient selecion
becomes even more important in implant based
reconstructions. Major complications are signicantly higher in obese, smokers, patients
with previous radiotherapy, axillary nodal
clearance, large breasts, higher implant volume
and bilateral cases [19]. Table28.1 summarizes
what one would consider to be an ideal
candidate.
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S. H. Ali and R. Parmeshwar
Table 28.1 A suitable candidate for an implant based
reconstruction
Suitable patients for implant based reconstruction
Younger patients <60
Good quality skin
Subcutaneous fat
thickness of 1 cmor more
Small to moderate size
breast(<450cc implant
requirement)
Realistic expectations
Non-smokers
Non-diabetic
No known atherosclerotic
disease
No previous breast
radiotherapy (RT)
Unlikely to need post
mastectomy RT
However, many of the risk factors such as diabetes, immunosuppresion,high BMI, likelihood
of need for post-mastectomy radiotherapy or
even smoking are relative contraindications and
if a decision is made to perform an implant based
reconstruction in breach of the above-mentioned
criteria of a suitable candidate, it must be a shared
decision makingprocess with all the information
made available to the patient, and with an acceptance of a higher risk of failure or suboptimal
outcome. Mitigation measures such as the use of
two-stage reconstruction, a total sub-muscular
technique or use of an adjustable implant with
optimization of any modiable risk factors such
as smoking and diabetes must be considered.
28.6 Implant Selection inBreast
Reconstruction
Selection of an appropriate implant is not only
crucial to an optimum aesthetic outcome, it is
also important in minimizing the immediate and
long-term complications.
The aim of an implant selection should be to
have an implant which sits comfortably in the
mastectomy pocket.
It shouldcompletely ll the pocketbut withoutcausing any tension on the suture line. On the
other hand, the shape of the reconstructed breast
depends on the selection of a correct style and
volume of the implant. It is usually taken that a
highly cohesive type, textured implant will be
chosen for most implant based reconstructions to
provide stable shape and to minimize rippling
and future capsular contracture.However, this is
a norm ratherthan a rule and some surgeons can
achieve good outcomes with smooth and round
implants and a casecan be made for the use of
smooth implants in view of the ongoingconcerns
around the link between textured implants and
BIA-ALCL.
Theselection of animplant is ideally made in
the outpatient setting using a measuring tape and
a calliper with patient standing or sitting erect in
a neutral position facing forward and shoulders
relaxed. The following dimensions are the minimum which need to be recorded.
• Breast width: maximum dimension from
medial most to lateral most point of the breast.
This is usually higher than the nipple level. It
is quite important to get the width right as this
is the most important of all the dimensions in
getting a good aesthetic outcome.
• Breast height: breast take off superiorly which
can be assessed by gently supporting the
breast from below and watching the upper
limit to lower most point at the lower pole in
the breast meridian.
• Projection: measured with a calliper from the
chest wall to the base of the nipple.
• Lower pole arc: from inframammary fold to
the nipple which helps ne tuning the selec-
tion of implant style to use.
These dimensions are carefully recorded and
documented along with any asymmetry from the
normal contralateral breast noted. It is a good
practice to mark and record the other important
breast dimensions of both the breasts as a matter
of routine such as nipple to supra-sternal notch,
nipple to midline distance and infra-mammary
fold level. It is interesting to observe that most
women will have some degree of asymmetry,
which if not noted, can be a source of unhappiness and in some cases complaints.
In calculating the implant size from externalbreast dimensions, it is vital that the double of
the skin and subcutaneous thickness is deducted
from the measured width and height (usually
upper pole skin pinch thickness). This corresponds to the inner dimensions of the pocket.
Failing to do so will lead to choosing animplant
which will be larger than required. Of all the
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b
Fig. 28.6 (a) Dimensions of an Implant. (b) Preoperative marking
dimensions in choosing an implant, the width of
the implant is the most crucial of the dimensions.
It should take priority in getting it right and
should be the last to be compromised if at all.
Intra-operatively it is good practice to use a
few sizers (templates of the actual implants) to
get a visual assessment of the reconstructed
breast shape and size with thepatient sittingup
before a nal decision is made on which implant
to use.
Figure 28.6a illustrate the dimensions of the
implants and how they vary in a round compared to
an anatomical one and how they can inuence the
shape of the reconstructed breast in an implant based
IBR.Figure28.6b shows the preoperative markings
which are essential before starting the procedure.
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