Lightweight implants in breast reconstruction

1 Introduction

Since the first use of breast implants by Cronin and Gerow in 1962 [1], who covered a core of silicone gel with a silicone shell and implanted it for breast augmentation, alternative filling materials for breast implants have been investigated several times.

As early as 1965, Arion [2] developed saline-filled implants for breast augmentation. Other research groups adopted this technique to allow partially filled implants to be inserted through smaller incisions and to be filled up in situ to final size [3]. Potential diagnostic difficulties in evaluation of mammography after implantation of silicone-gel filled implants led to the development of triglyceride-filled implants in the 1990 s, which allowed much better verification of malign or benign lesions of the mammary gland after breast augmentation [4]. However, degradation products of the material were subsequently suspected of having negative side effects, so in 2000, among other countries, the U.K. Medical Device Agency recommended explantation and many of these implants were removed [5]. PVP hydrogel, another “biological” filling material for breast implants, was used as an alternative for silicone gel towards the end of the last century [6]. After several unexpected enlargements occurred in various studies and many of these implants were removed again, this filling material was also withdrawn from the market [7].

Last decade, Govrin-Yehudain et al. developed a new filler for breast implants in which borosilicate-based microspheres are embedded in conventional silicone gel, resulting in a weight reduction of 30% compared to conventional silicone-gel filled implants [8]. The reduced weight is expected to result in reduced postoperative pain, with the authors suggesting that weight plays a greater role than volume in the development of pain [9]. However, in their publication about the effect of lightweight implants, only patients who had undergone aesthetic breast augmentation were followed up; an investigation of women with reconstructive indication is not described up to now.

Diagnostic methods and reconstructive techniques for the treatment of breast cancer have developed rapidly during the last decades [10, 11]. Especially in patients after mastectomy who are reconstructed with an anatomic implant, the implant weight seems to be of particular importance. It is to be expected that the average implant volume for breast reconstruction, as it was seen for example in our study, is larger than that for breast augmentation [12]; also, especially in the postoperative healing phase, it can be assumed that bigger implants in combination with a larger wound area after mastectomy generate a higher rate of implant-associated complications. Beneath that, the overall risk to develop capsular fibrosis is higher in case of reconstruction than in aesthetic augmentation [13].

In our clinic, a total of 91 lightweight implants have been inserted in 57 female patients for aesthetic and reconstructive reasons since 2019. In this retrospective study, we exclusively investigated the women with reconstructive approach and compared them with patients reconstructed by conventional implants during the same period. In addition to biometric data and implant size, capsular fibrosis, complications and explantation rate were evaluated.

2 Materials and methods

From January 2019 to March 2022, 61 lightweight implants were inserted in 40 patients with reconstructive indication (21 times bilaterally). During the same period, 58 patients with reconstructive indications received 91 conventional silicone gel-filled implants from the same manufacturer (Polytech Health & Aesthetics GmbH, Dieburg, Germany). The same implant design (anatomical shape, with round base) and the same surface texturing (POLYtxt) with a texturing size of 35μm were used in both groups of patients.

Inclusion criteria were patients with reconstructive indication after mastectomy. 'Reconstructive' was defined as procedures in which immediate or secondary reconstruction was performed after mastectomy or in patients who underwent prophylactic mastectomy, e.g., for genetic mutation.

Exclusion criteria were reconstruction for congenital malformation such as Poland syndrome and augmentation for aesthetic indication.

Data collection was retrospective using patient records, image files, and follow-up examination records; follow-up period was finished at the end of May 2022.

Patients who met the inclusion criteria were divided into two groups: Group A with reconstruction by lightweight implants and Group B where conventional silicone gel-filled implants were used.

In the following, the results are summarized using descriptive statistics. This includes the mean and standard deviation of the various values. The calculations were performed using Excel 365.

3 Results

Women in group A (lightweight implants) were on average 47 years old (range, 24–77), weighed 72 kg (range, 55–116 kg), and were 167 cm tall (range, 158–180 cm) with an average BMI of 25.9 kg/m² (Table 1). The right side was operated on 32 times and the left side 29 times. 38 procedures followed reconstruction of tumor disease; severe mastopathy was treated by mastectomy two times, and reconstruction after prophylactic mastectomy was performed 21 times.

Implants had an average volume of 452 ml (range, 250–735 ml) and an implant weight of 317 g (range, 175–515 g; Table 2). The average follow-up time was 259 days. In both groups, nearly 50 % were operated on both sides, which is compared in Table 3.

Two patients had to undergo therapeutic irradiation and subsequently suffered capsular fibrosis grade 2 and 3, respectively. In 5 cases, an acellular dermal matrix (ARTIA, LiveCell Corp., Branchburg, New Jersey, USA) was used additionally.

In terms of complications, hematoma was registered in four cases and wound healing disorder also four times. Twice, a rotation of the implant of more than 45° was noted. Six times capsular fibrosis 3.-4.° was seen (twice after radiotherapy), which in three cases led to replacement of the implant in the later course.

A major complication was defined as surgical revision during the first 30 days after surgery. Three revisions were necessary due to hematoma.

Later, until the end of the follow-up period, six implants were replaced: once because of capsular fibrosis, once due to seroma, twice because of infection (in one case the implant had been inserted as salvage procedure after infected flap necrosis) and two times because of implant rotation of more than 45° (Table 4).

Patients in group B (conventional silicone gel as filling material) had an average age of 46 years at the operation (range, 25–71a) and were 166 cm tall (range, 154–184 cm) with a weight of 64 kg (range, 45–91 kg). Their body-mass-index was 23 kg/m². The right breast was operated on 48 times and the left side 43 times (s. Table 3). In 50 procedures, reconstruction was required after tumor disease, and in 41 cases reconstruction was performed after prophylactic mastectomy.

The implants used were on average 347 ml in size (range, 150–550 ml) with comparable weight of 347 g (1 ml = 1 g). The average follow-up time was 172 days.

Irradiation had been performed in 6 cases; in 33 operations, acellular dermal matrix (Artia) was used.

Hematoma occurred 6 times, with 4 times requiring blood supply. Wound healing disorders or infection had to be treated 7 times and skin necrosis once, with implant removal required in one case.

6 times capsular fibrosis was observed, which led to implant exchange in 3 cases in the later course.

As major complication within 30 days, two revisions due to postoperative bleeding and one due to infection were recognized.

After this period, four implants were replaced or removed: three times because of capsular fibrosis and once because of infection.

In one of the few published studies on lightweight implants, the authors postulated less pain postoperatively compared to conventional silicone gel-filled implants and interviewed 50 patients after B-Lite augmentation and a comparable group of women after augmentation with conventional silicone gel-filled implants [9]. As a result, a reduction in analgesic requirements during the first 4–7 days was noted after the use of lightweight implants. In another retrospective study of aesthetic patients, the same authors investigated high patient satisfaction after augmentation with lightweight implants [14]. However, in this study different manufacturers with different surface techniques were compared, so that any influence of the respective surface structure and the different shape of the inserted implants cannot be excluded.

To our knowledge, no published study investigated patients after breast reconstruction with lightweight implants up to now.

The influence of different surface structures on the outcome of breast reconstruction with implants, especially regarding capsular fibrosis, has been described several times [15–17]. This could be excluded in our study because all implants had the same surface structure and the same shape (anatomical, round base) and are produced by the same manufacturer (Polytech, Germany). However, the two types of implants investigated in this study differ in their filler material, with both products using silicone gel, but enriched with gas-filled microspheres at the lightweight implants [8].

It has been shown in the past that implant fillers also can have an effect on the outcome after breast implant insertion. PVP-hydrogel-filled implants developed capsular fibrosis more frequently than saline-filled implants with comparable surface structure [18]. Saline-filled implants showed a lower rate of capsular fibrosis but higher percentage of deflation than silicone gel-filled implants, depending from the manufacturer [19].

According to the manufacturer’s descriptions, the filler of the lightweight implants, as investigated in this study, should primarily lead to a reduction of the implant weight and thus to reduced pain. This effect is to be expected to a greater extent in the case of reconstructive use, since here the volume of the entire mammary gland has to be replaced after mastectomy and not only an enlargement of the existing mammary gland tissue is to be achieved.

In our retrospective analysis, only patients with reconstructive indications were included. It is remarkable that the volume of the implants differed relevantly in the two groups. While implants with an average volume of 347 ml were inserted in group B with conventional silicone filling, the volume of the lightweight implants in group A was 453 ml in average. In group A, both body weight and BMI were higher than in group B, so the indication for a lightweight implant was more likely to be for larger reconstruction volume. The lightweight implants had only 316 g in average due to their lower density, so the weight load from the inserted implants was comparable in both groups.

In terms of complications, the number of postoperative hematomas was comparable in both groups (4 of 61 breasts in group A and 6 of 91 breasts in group B). Capsular fibrosis grade 3 to 4 was noted 6 times in group A and 6 times in group B, with subsequent replacement required in 3 cases each. While the number of wound healing failures was higher in group B, rotation requiring revision occurred in 2 cases of the lightweight implants.

As demonstrated in our study, the indication for lightweight implants was preferably seen in case of higher volume requirement. Interestingly, the volume of the implants in patients who received lightweight implants and suffered complications was higher than in patients without complications (494 ml vs. 436 ml; as complications were regarded revisions and capsular fibrosis 3.-4.°). To conclude that implants with higher volume could generate more often complications, further studies with higher numbers of patients are necessary.

5 Conclusion

The use of lightweight implants seems to be a reasonable option especially in reconstructive surgery for larger resection volumes to reduce the weight of the implant. One reason for the higher incidence of capsular fibrosis and implant rotation found in our study can be seen in the larger implant volume and has to be investigated in further studies.

Limitations

Limitations are the retrospective study design and the limited number of patients in both groups.

Funding

The authors received no financial support for the research or publication of this study.

Disclosures

N. Heine has given one presentation and two advisory boards for Polytech.

Ethical approvement: Ethics Committee, University Regensburg, No. 20-1874_1-101.