Expander-implants breast reconstructions

14 Expander-implants breast reconstructions







History



Development of breast implants


The history of breast implants starts in the 19th century, when the first attempts to augment a breast were recorded. Ironically, and in-keeping with modern research on tissue regeneration, one of the first techniques described was based on the transfer of a lipoma from the back to the breast area.1 Further attempts were made across the years, adding the most heterogeneous materials (from cartilage to soya-bean oil, including a various number of copolymers). Free silicone was used for augmentation in a large number of women who developed severe complications because of this practice. Silicone implants, as currently engineered, were employed for the first time at the beginning of the 1960s. A silicone bag filled with fluid silicone was inserted for breast augmentation. The first generation of implants had a quite thick shell to prevent gel migration; some products were provided with anchoring systems that demonstrated their uselessness and created stress points in the prosthesis, with possible ruptures and gel migration. The inner gel was quite viscous to keep a proper shape.


This generation of implants suffered high capsular contracture rates and occasionally, ruptures and gel leakage were reported. They were replaced by the following generation who had a thinner envelope and a more fluid gel. These new devices were expected to reduce capsular contracture rates and provide a more natural feeling. Notwithstanding the efforts of the engineers, the final results were worse than expected with severe contracture rates, ruptures and gel migration.


The third generation devices were designed with a thicker silicone shell build, with up to three layers to prevent migration of low molecular gel silicone, as it has been supposed that gel migration could be involved in capsular retraction. The modern implants are filled with a complex three-dimensional matrix of cross-linked silicone molecules that keep a memory of the shape and do not migrate outside, even in the case of macroscopic ruptures of the devices. Progresses were done also in the prevention of malpositioning and in reducing capsular contracture, thanks to textured surfaces. Texturization was introduced in the market in the late 1960s; a foam of polyurethane was used to coat the implants and to prevent their migration. However, this surface tended to be destroyed by the immune system, leaving the implant underneath uncovered and smooth. This generated a thick and complex capsule made up of a fibrous immune reaction, mixed with foam fragments that made the surgical removal particularly difficult.


The texturization of modern implants was introduced by McGhan (currently Allergan) in 1987 (Biocell) made directly on the shell of the device applying pressure while on a layer of fine salt. In 1998, Mentor created the Siltex surface whose texture was generated using a contact imprinting from a textured foam. Both products are currently on the market.


The current generation of implants have evolved both on their content and on external shape. The Style 510 from Allergan can also be filled with two different kinds of gel, more cohesive on the top to provide over-projection and softer to provide a more natural feeling. Modern implants have also evolved in their external shape and volume. The most advanced manufacturers provide a huge range of different shapes and volumes commonly based on implant width, height, and projection on the chest wall.



The controversy regarding silicone implants


Silicone implants were manufactured and commercialized in the United States for a very long period until the FDA, in 1998, following several reports on complication and illness, asked the manufacturers to provide data regarding the safety of their devices. In 1992, silicone breast implants were limited to use in clinical trials of women undergoing mastectomy and breast reconstruction. This decision was due to a lack of evidence in implant duration and effectiveness for aesthetic purposes (IOM report). In 1997, the moratorium was kept in place after the FDA review that confirmed a persistent lack of data regarding safety. In the same year, the IOM started the most extensive research on the effects of implants in breast procedures. In 1999, a final report was released and it confirmed that although breast prosthesis can cause local problems such as capsular contracture, there was no relationship between systemic disease (including cancer or connective tissue disease) and silicone implants.


In 2000, on the basis of this report, the FDA (and thanks also to internal studies from the most important manufacturers demonstrating that despite local problems, most of the women who received implants were satisfied) approved saline-filled implants.


In 2006, the FDA finally granted the approval for the most important manufacturer, although there were still some restrictions including a requirement to complete the 10-year studies on women already implanted and providing a 10-year study on the safety of the devices in 40 000 women. The post-approval studies are closely monitored by the FDA.


Silicone-filled implants are currently on the market in the United States and women are advised to have a breast MRI regularly to identify rupture and to prevent silicone leakage. Women undergoing breast augmentation should be carefully counseled about the risks of the procedure and the manufacturers are compelled to produce detailed leaflets for the patients.



Basic science


Basic science in the field of breast implants, no differently from other branches of plastic surgery, is affected by a generalized lack of evidence. Most of the researches currently published in international journals are based on very empirical observations and rely mainly on expert opinions or on small retrospective series. A recent systematic review on the assessment of health-related quality of life included2 a total of 34 papers and most of them appeared to be compromised by poor statistics, lack of reproducibility due to the use of generic instruments of evaluation, reliance on single center’s observations and no unequivocal reports on complications. Furthermore, among the 34 examined papers, only two were based on level 1 evidence and 11 on level 2. The authors conclude that there is an urgent need for standardized instruments for outcome evaluation to provide a reliable guidance for further research.


Basic research on implants is strictly tightened to breast shape assessment. A quantitative analysis of breast shape and of its modifications over times is not possible, the few tools proposed in literature have been tested by our group with very disappointing results. A more precise geometrical language should be available and estimates from geometry of curved surfaces should replace currents linear measurements that are unable to assess complex round territories like the female breast.3


Capsular contracture cannot be assessed without such estimates. A three-dimensional representation of the mammary appearance allows an objective evaluation of breast changes following cosmetic and reconstructive surgery.


Research efforts should also be made to analyze the breast deformation during walking or with the movements of the trunk and of the arms. In fact, the breast is not a static object and capsular contracture mainly affects breast softness and plasticity.4,5


Capsular contracture has been widely investigated as the major trade-off of prosthetic reconstructions. Several explanations have been proposed according to endogenous or exogenous hypothesis and capsular contracture appears to be a multifactorial clinical condition related to surgical technique, implant manufacturing, anatomical plane of implantation, etc. Infections can be the leading cause generating this condition.6,7 This theory gives explanations for asymmetric contractures and for effective reduction using implants in association with topic antibiotics or iodopovidone,7 and is supported by studies that demonstrate a much higher percentage of positive culture rates in severely contracted capsules (89.5% vs 10.5% in grades I and II).8


Any convincing theory for capsular contracture is tightly related to an upregulated response to foreign bodies. Several logistic mediators, together with fibroblasts, macrophages and CD4 are involved in this process, and it has been argued that a good treatment could be related to topic or systemic administration of anti-inflammatory drugs. Leukotrienes such as zafirlukast have been investigated with positive results.9


In this series of 37 patients who underwent primary submuscular breast augmentation with saline-filled, smooth implants, were evaluated by independent observers and rated for capsular contracture using a modification of the Baker classification. Patients who suffered capsular contracture were offered zafirlukast 20 mg for 3 or 6 months. A total of 41 breasts in this series (55.0%) were found to have early, mild capsular contracture. Favorable results with complete or partial response to treatment were seen in a statistically significant proportion of the treated breasts (75.7%, p<0.05). This response lasted in the long term (mean follow-up of 16.5 months).


Our research group confirmed this observation in an experimental study,10 in which we evaluated the effectiveness of zafirlukast. Disks of textured implant material were placed dorsally into each of the subcutaneous tissues of 40 rats that were subdivided into two groups: 20 rats treated with zafirlukast and 20 controls. At autopsy 77 days after treatment, each implant with its surrounding collagenic tissue was excised, and the macroscopic measure of the membrane thickness was compared with the pathology reports, to definitely assess the foreign body reaction. The mean total thickness of the capsule around the implants was 161.97 µm in the zafirlukast-treated group compared with 345.98 µm in the control group (p<0.001). Outstandingly, the collagen fibres and fibroblast layer were reduced in the zafirlukast-treated group compared with the controls. Our study confirms the effectiveness of this compound in preventing fibrosis and reducing the extent of collagen reaction when a capsule has been formed.


Several clinical investigations of the effects of shell texturization in preventing capsular contracture were conducted. Barnsley11 performed a meta-analysis of seven trials1220 comparing smooth and textured implants; only three of these studies demonstrated significantly lower rates with the use of textured implants. However, a pooled analysis of all seven studies demonstrated an odds ratio (OR) of 0.19 indicating a protective effect for surface texturing on the rate of capsular contracture. The only subgroup who did not benefit from texturization was the one belonging to a single trial, in which the implants were put in a sub-muscular position.


A further meta-analysis of trials of subglandular breast augmentation by Chin-Ho Wong21 reported similar results, although several limitations were correctly pointed out by the authors. Although in the presence of clinical trials with a robust design (prospective controlled randomized), the outcome evaluation is substantially biased by subjective and non-reproducible observations, as capsular contracture was assessed according to the subjective Baker scale. The authors correctly stated that clinically important contractures (Baker III and IV) were defined as capsular contracture in all studies and that two or more observer independent examiners were employed for patient evaluation and that discordant opinions were solved by consensus. Moreover, other limitations arise from the lack of standardization of surgical techniques and incision approaches, the short-term follow-up (only two studies with a follow-up longer than 1 year), with several patients lost to follow-up and consequently data deterioration after the first year of observation. Notwithstanding the efforts in providing a higher level of evidence, more objective and quantitative tools for assessment of the outcome of plastic surgery of the breast should be provided.


The use of human acellular dermal matrix has been reported as a possible tool for prevention of capsular contracture. A study by Basu and colleagues22 on 20 patients who underwent two stage breast reconstruction, investigated the histopathologic characteristics of the capsule in the bio-integrated area and in the native subpectoral capsule. A semi-quantitative analysis was performed, the scores were statistically analyzed and significant differences were observed in favor of the acellular dermis. The acellular dermal matrix facilitates breast reconstruction, avoiding the harvesting of the serratus muscle; it also provides a good definition to the lower pole of the breast and a more natural ptosis. However, in this study it is demonstrated that the acellular dermal sheet, consisting in a biological matrix deprived of cells, allows the implantation of cells and vessels from the host, establishing a physiological matrix cell interaction. For this reason, host cells are able to revitalize the exogenous matrix, also containing extracellular matrix proteins (such as hyaluronic acid, fibronectin, collagen, and fibronectin), facilitating normal wound healing and avoiding chronic inflammatory changes and foreign body giant cell formation.2325


The beneficial effects of the acellular dermal matrix in the prevention of long-term complications such as capsular contracture or poor morphological results may be hindered by a higher percentage of short-term severe complications.


The largest series on this device reports on two groups of patients who underwent breast reconstruction either using the acellular device or not. The seroma and infection rates were higher in the acellular dermal matrix group (14.1% vs 2.7%, p = 0.0003, for seroma; 8.9% vs 2.1%, p = 0.0328, for infection) and acellular dermal matrix and body mass index were statistically significant risk factors for developing seroma and infection. The authors concluded that although the acellular dermal matrix enhances final results, a higher short-term complication rate is awaited (OR seroma 4.24 times, p = 0.018 and infection 5.37 times, p = 0.006).26


Similar conclusions are report by Newman et al.27 in a recent meta-analysis, in which they concluded that the incidence of short-term complications with human acellular matrices is approximately 12%.



Breast reconstruction with tissue expansion and permanent implants


Factors including the type of mastectomy, timing of reconstruction, tissue expansion, and implant design have made expander-implant techniques an important method for breast reconstruction. Tissue expansion was first reported by Neumann in 1957, for coverage of a subauricular defect.


Although Neumann’s28 report appeared in Plastic and Reconstructive Surgery and demonstrated the feasibility of the procedure, major interest in tissue expansion did not occur for another 20 years. Working independently, Radovan29 and Austad30 developed silicone tissue expanders and published their findings in 1982. Radovan performed his first tissue expansion in 1976. Austad developed a self-inflating silicone prosthesis and investigated the histologic effects of tissue expansion. Subsequent to this early work, tissue expansion has been investigated thoroughly and gained widespread acceptance on the basis of its proven safety and efficacy.


The silicone implant was initially incorporated into breast reconstruction as a device to provide a safe and stable breast mound. At the time of its inception, the radical mastectomy and modified radical mastectomy were routinely used to extirpate breast cancer. The implant could rarely be used under the preserved skin envelope because of existing scar tissue and inadequate and often unstable skin coverage at the mastectomy site. Therefore, the implant was used in conjunction with a flap for coverage. With the evolution of mastectomy techniques and diagnosis of breast cancer at an earlier stage, more conservative approaches to mastectomy, including skin-preserving and skin-sparing mastectomy, have been used. With increasing recognition of the value of immediate reconstruction for the mastectomy patient, the option of expander-implant became more practical for incorporation into techniques for reconstruction.


With the development of the concept of tissue expansion, a deflated implant can be inserted beneath the mastectomy skin that will not adversely affect mastectomy skin survival. The expander can subsequently undergo inflation both to stretch the dimensions of the retained skin envelope and to avoid wound contraction during the process of wound maturation after the mastectomy. With improvement in the design of tissue expanders, the port is now incorporated into the surface of the implant, eliminating the dissection distant to the mastectomy site to place the valve for later expander inflation. With the use of a textured expander, the expander will not migrate away from the area of greatest skin tightness (usually the inferior half of the preserved breast skin envelope) and will maintain a well-defined inframammary line, despite the mastectomy dissection. These innovations have made the expander-implant for breast reconstruction a reliable technique to restore form at the site of mastectomy. The process of reconstruction with the use of an expander-implant is generally a two-stage procedure.


The first stage is insertion of the expander either at the time of mastectomy or delayed until the patient is referred or presents for reconstruction. If the first stage is not performed at the time of the mastectomy, it is preferable to delay reconstruction a minimum of 3 months and until adjuvant treatments are completed.


The advantages of the expander-implant technique for breast reconstruction include the following:



The disadvantages related to expander-implant use include the following:



Certain general criteria are required before a patient represents an appropriate candidate for implant-expander reconstruction



The patient must be well informed about all options for breast reconstruction. In general, autogenous breast reconstruction will provide a more natural breast but will require more complex surgery and additional donor site scars. The patient must be willing to accept the use of a permanent prosthesis. At present, both the silicone gel- and saline-filled implants are approved by the Food and Drug Administration (FDA) for breast reconstruction.31


The technique for expander-implant use generally requires two stages. Each stage is discussed in regard to marking, position, dissection, closure, dressing, and postoperative care. Special considerations, including single-stage expander-implant reconstruction, techniques for expander-implant muscle coverage, alternative approaches for expander-implant use in patients with an inadequate skin envelope, and outcomes, are also reviewed.


The expander-implant breast reconstructions have evolved during the last few years (Fig. 14.1). In the past, prostheses were mainly employed to reconstruct small breasts; nowadays, thanks to the modern anatomical devices, it possible to reconstruct a cosmetic medium-sized bosom (with contralateral adjustment) for all patients, independently from the original breast shape. We contraindicate this technique only to previously radio-treated patients.




We validated a modern surgical model for two stage reconstructions and we expanded the indication to one stage reconstruction with a new technique called “Skin reducing mastectomy” (Fig. 14.2). This technique is currently under development at our institution and it allows one stage reconstruction in women with large breasts with contralateral symmetrical scarring. Implant reconstruction can be performed either in the same surgical time of the mastectomy or as a delayed procedure (Fig. 14.3).











Reconstructive paradigms and surgical strategy


An established paradigm for breast reconstructions to rebuild, after mastectomy, an identical and possibly symmetrical breast mound is required. Autologous flaps were favored in the reconstruction of large and ptotic breasts due to their ability to reproduce a natural symmetry even with a contralateral ptotic gland. Reconstructions with sub-pectoral implants were indicated mainly for small and medium-sized glands with a moderate degree of ptosis. Operations on the healthy breast in search of symmetry were considered undesirable, as they were expected to compromise surveillance on contralateral disease.32,33


Extra-projection devices gave us the chance to modify this reconstructive predicament (Figs 14.4, 14.5). Modern anatomically-shaped implants can be employed for breast reconstruction and can spare women from complex operations that, as far as myocutaneous flaps are concerned, can generate severe biomechanical complications.




Extra-projection prostheses filled with highly cohesive gel can yield not only a rewarding cosmetic outcome but a safe surgical approach (Fig. 14.6).34,35






In the authors’ experience, breast reconstructive surgery aims to create, for all women, a bilateral cosmetic medium-sized breast (400–500 cc), highly projected, with little to moderate ptosis, rather than a ptotic gland exactly matching the contralateral. This is demonstrated by the medium volume of implanted prosthesis in comparison to the contralateral adjustment technique; this ranges from 397 cc for women with small breasts who received an augmentation, to 533 cc for those whose healthy side required reduction surgery.36


Our approach substantially differs from that reported by Losken et al.33 in one of the largest series on breast reconstructions. In this work, one-third of patients who underwent breast reconstruction did not receive contralateral adjustment, whereas this incidence in our experience does not exceed one case out of ten.


The reconstruction of the large breast can be easily accomplished also using implants, coupling it with a contralateral reduction. A modification of “Wise pattern” mastectomies that we called “Skin reducing mastectomy” may allow one stage reconstructions with symmetrical inverted T scarring. Also small and very small breasts can be reconstructed in a single stage.


The observation of sub-groups stratified according to operations on the opposite site demonstrated that the cosmetic and reconstructive purpose of this methodology is emphasized when implants are used also contralaterally (Fig. 14.7). A higher satisfaction rate is reported in this case, while on the other hand ptotic breasts treated only by mastopexy tend to recur over years (Fig. 14.8). We are aware that women who have developed breast cancer are at a higher risk of a second malignancy in the contralateral breast;37 for this reason contralateral augmentations in this setting are still debatable.





In healthy women, it is well known that despite the diminished sensitivity of mammography with implants, augmented and nonaugmented patients are diagnosed at a similar stage and have a comparable prognosis.36 Much longer follow-up in this study and the increased role of MRI will probably also clarify this aspect.38


The adjunct value of contralateral reduction relies on the possibility to identify contralateral occult breast carcinomas. The incidence of occult cancer in the histology specimen as previously reported, after reduction mammoplasty is not high, but still needs to be taken into consideration. The postoperative specimen should be marked as for common excisions and if any incidental lesion is postoperatively discovered, this will require an axillary evaluation in a second surgical stage. Positive margins can be occasionally re-excised, although in some cases a mastectomy could be the best option for optimal local control. All patients scheduled to undergo a contralateral adjustment should be preoperatively assessed with clinical examination, mammography and if required, ultrasound. Any suspicious condition needs to be reported and investigated. The follow-up should not be different from that commonly done for breast cancer patients.



Diagnosis and patient presentation


According to our reconstructive strategy, the choice for implant-based reconstructions should not be driven only by dimensional considerations.



Exclusion criteria


Prosthesis for reconstructions can be employed in all women undergoing immediate or delayed breast reconstructions that did not receive previous radiation. Several studies demonstrated a higher complication rate after implant positioning in a radio-treated field.3941 Similar observations are reported for the reconstructed breast receiving radiotherapy on temporary expanders. For this reason, patients preoperatively scheduled to undergo radiotherapy for locally advanced breast cancer are discouraged to undergo an immediate reconstruction and a delayed flap-based reconstruction is recommended (Fig. 14.9).




Radiation therapy determinates a progressive change of the skin surface that originates in an inflammatory chronic condition. We can observe early effects and long-term effects. The first occur within 90 days of treatment and include dryness, epilation, pigmentation changes, and erythema.42 After 90 days, a chronic logistic condition may appear with progressive induration of the skin, fibrosis, and oedema. The ultrastructural analysis of this condition reveals clear signs of ischemia, with capillary vessels reduced in number and exhibiting duplication of the basal membrane, ectatic lumen cytoplasmic activation of endothelial cells.43 Any attempt to perform alloplastic reconstruction in this setting of chronic ischemia has demonstrated to yield an unacceptable rate of severe complications with implant extrusion, capsular contracture or implant displacement.39,44 A trial is ongoing in our institution for patients whose indication for radiation is not known before mastectomy. In such cases we perform an immediate two-stage breast reconstruction. Patients undergo tissue expansion during postoperative chemotherapy and once the second stage of the reconstruction has been accomplished, they receive radiation on the permanent implant. According to preliminary results, this strategy has extended the indications for implant-based reconstruction also to women requiring post-mastectomy radiotherapy. This strategy allows reduction of the complication and extrusion rates, especially in comparison with patients who receive radiation on tissue expanders. The capsular contracture rate of irradiated breast reconstruction is clearly higher and in accordance with that reported by other authors.45 However, we observed satisfaction rates not particularly different from that reported by patients who did not received radiation.


Women who received neoadjuvant chemotherapy for large nonadvanced tumors that still require a mastectomy are expected to complete their treatment with radiation before change of temporary expanders with permanent implants. In these cases, due to the high complication rate, it is advisable to warn the patients about the risk of extrusion and make them aware of the possible need to change to a “flap-based” reconstruction strategy.


Fat grafting to treat radio-induced damages of soft tissue is being widely employed in the field of breast reconstruction with prosthesis (Fig. 14.10). This simple procedure, commonly performed under local anesthesia, has changed the fate of reconstructions at high risk of complications. Since the first report from Rigotti et al.,43 who described the effectiveness of transplantation of lipo-aspirates to treat radio-induced inflammation, other authors have confirmed the effectiveness of this technique. Serra-Renom et al.46 for instance, recently demonstrated that in mastectomized patients who received radiotherapy, fat grafting in addition to traditional tissue expander and implant breast reconstruction will lead to better reconstructive outcomes with the creation of new subcutaneous tissue, accompanied by improved skin quality of the reconstructed breast without capsular contracture.




Inclusion criteria according to dimensional considerations


All non previously radio-treated patients can be candidates to immediate or delayed reconstructions and are subdivided into three subgroups according to breast shape and size. As demonstrated by our report, contralateral adjustment plays a major role in implant-based breast reconstructions.





Feb 21, 2016 | Posted by in General Surgery | Comments Off on Expander-implants breast reconstructions
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