Poly-4-hydroxybutyrate mesh (GalaFlex®) in aesthetic breast surgery: A comprehensive systematic review

Abstract

Background

Mastopexy, with or without implants, is a common cosmetic breast surgery. Despite various techniques, long-term issues like pseudoptosis and recurrent ptosis remain challenging, especially in patients with poor skin quality or significant weight loss. While autologous methods provide stability, they often fall short in complex cases. Therefore, non-autologous reinforcement, such as acellular dermal matrices (ADMs) and synthetic meshes, are increasingly used. This systematic review critically evaluates the efficacy, safety, and outcomes of P4HB mesh in aesthetic breast surgery, focusing on postoperative complications and patient satisfaction.

Methods

This study followed Cochrane Handbook principles and PRISMA guidelines, with the protocol registered on PROSPERO (ID: CRD42024506060). Analyzing 183 patients (366 breasts) across seven studies, high heterogeneity, the absence of a control group, and a significant risk of bias precluded the possibility of conducting a meta-analysis, resulting in a systematic review instead.

Result

This review evaluated the use of P4HB scaffolds in various breast surgeries, including mastopexy, augmentation, and revision procedures. Findings demonstrated improvements in breast support and lower pole stability over time. Complications were minimal. However, the studies highlighted outcome variability and the need for standardized assessment tools to measure results.

Conclusions

The P4HB mesh offers notable advantages, including high biocompatibility, long resorption time, and cost-effectiveness, making it a promising option for challenging cases in aesthetic breast surgery. It provides internal support for soft tissues and implants, especially where implant visibility is a concern. However, due to the variability in surgical procedures and the lack of robust evidence, solid conclusions about the optimal clinical use of P4HB meshes are still premature, necessitating further high-quality studies.

Introduction

Cosmetic breast surgeries are among the most common procedures in aesthetic surgery, with over 475,000 procedures performed only in the USA, according to the American Society of Plastic Surgery in 2022.

Mastopexy, combined or not with a breast implant, is one of the most performed aesthetic surgery interventions; multiple techniques have been described over the last decades, with different skin incision patterns and glandular pedicles.

Irrespective of the procedure, the main drawback of mastopexy at a distant follow-up is the development of pseudoptosis and recurrent ptosis over time, especially in patients who have poor skin quality or have experienced significant weight loss, which represents a significant challenge in the field of aesthetic breast surgery. A diffuse reduction of the support provided by the skin envelope and the relaxation of breast ligaments are the leading causes of ptosis relapse. Instead, bottoming out or pseudoptosis is a significant deforming condition characterized by an increase in the nipple-inframammary fold (N-IMF) distance, which dislocates the nipple over the point of maximum projection of the breast cone, with an excess of breast volume in the lower pole.¹

In many patients, tissues of poor quality, characterized by reduced elasticity, are often insufficient for providing enough support over time. Several methods have been described to avoid excessive tissue descent and stabilize the lower pole and the N-IMF distance. Different proposed solutions involve tissue suspension, glandular fixation, and flap techniques, e.g., quilting parenchymal sutures, dermo-glandular plication, superficial fascial system suspensions, fixation to the pectoral fascia using de-epithelialized dermal strips, subdermal flaps, parenchymal flaps, dermo-glandular pedicles, dermal bras, and fixation of breast tissue to the chest wall with submuscular auto-augmentation.2, 3, 4

Nonetheless, even though fully autologous techniques can provide stability in many patients, they are often insufficient, especially in complex cases like secondary cases, patients with massive weight loss, and mastopexies combined with high-volume implants. Therefore, using non-autologous supplementary tissue reinforcement appears to be a rational strategy.⁵ Different devices have been introduced to increase soft tissue coverage and lower pole support. Both natural and synthetic materials have been used for this purpose. Acellular dermal matrices (ADMs) are built of collagen and extracellular matrix derived from allogenic or xenogenic sources, organized in a 3D structure.⁶ Their strengths are optimal biocompatibility and full integration in the host tissues. However, the high costs and a relatively increased risk of seromas limit their use in cosmetic surgery.7, 8, 9 An alternative to ADMs is synthetic meshes, initially documented by Johnson and Goes.^10,11 Different synthetic materials have been used: non-resorbable (e.g., polypropylene or titanium-coated meshes) and resorbable (e.g., PLA/PGA: TMC, silk fibroin, PDO, PGLA, P4HB). The synthetic mesh induces the formation of fibrous tissue, which may serve as an internal support system¹²; however, the stability and long-term aesthetic outcomes remain subjects of ongoing investigation and debate. However, synthetic materials provide an alternative instrument and may represent a significant new option in soft-tissue support. Specifically, their reduced costs are attractive for extending their use to aesthetic surgery patients, even though biocompatibility and an increased burden of foreign materials in the surgical site are still open issues, as much as their long-term efficacy.

The utilization of Poly-4-Hydroxybutyrate mesh (P4HB) (GalaFLEX; Galatea Corp., Lexington, Mass.) has emerged as a promising adjunct to traditional breast augmentation and revision surgery. P4HB mesh is designed to provide structural support and promote tissue integration, potentially enhancing the overall aesthetic results and longevity of breast surgeries.¹²

As the popularity of P4HB in aesthetic breast surgery continues to rise, it becomes imperative to critically evaluate and synthesize the existing body of evidence surrounding its efficacy, safety, and clinical outcomes. This systematic review aims to comprehensively assess the current knowledge regarding using P4HB mesh in aesthetic breast surgery. It explores its impact on pivotal parameters such as postoperative complications, patient satisfaction, and long-term aesthetic outcomes. Furthermore, introducing P4HB mesh into surgical practice prompts crucial questions regarding patient selection, surgical techniques, and the comparative effectiveness of the P4HB scaffold in various breast surgery contexts.

Methods

This study adhered to the principles outlined in the Cochrane Handbook, and results were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.^13,14 Since all the reported data was obtained from the available published literature, this study meets exemption status for informed consent or Institutional Review Board approval. The protocol for this systematic was prospectively registered on the International Prospective Register of Systematic Reviews (PROSPERO) (ID: CRD42024506060).

The Patient-Intervention-Comparator-Outcome-Study Type (PICOS) Framework was used in developing the literature search strategy: patients (P) - female worldwide (>18 years old); intervention (I) – reduction mammoplasty, breast augmentation, revision breast augmentation, mastopexy, and augmentation-mastopexy; comparator (C) – not applicable; outcome (O) – safety and effectiveness of P4HB mesh support; study type (S) - prospective and retrospective studies. Specifically, randomized controlled trials (RCTs) and non-RCTs were included. RCTs were excluded if a crossover or cluster-randomized design was presented. In addition, both prospective and retrospective non-randomized studies (NRSs) were included. The outcomes from the most recent publication for each study were analyzed. Notably, studies were excluded if: (a) they were not reported in English; (b) the data were reported in non-peer-reviewed journals (e.g., institutional or personal databases); (c) the article type was a conference abstract, a review, a thesis, a case report, a book chapter, or a letter to the editor.

An electronic search was performed on PubMed, Web of Science, and EMBASE using relevant keywords, phrases, and medical subject heading (MeSH) terms (Supplemental Table 1). The snowballing method (i.e., screening all the articles that the already included papers cite) was applied to the reference list of included articles to screen for additional RCTs and NRSs.

Two reviewers independently conducted the electronic literature search (IN, GS). The reference lists from the three databases (PubMed, EMBASE, Web of Science) were merged, and duplicate entries were removed using the reference management software COVIDENCE (Veritas Health Innovation, Melbourne, Australia). After screening titles and abstracts, the full texts of the remaining papers were analyzed. In the presence of eventual discrepancies in the selection process, a third reviewer was consulted (MP). Based on the PRISMA 2020 flow diagram template for new systematic reviews, a flow diagram for identifying relevant reports is illustrated in Figure 1.¹³

Figure 1.

Flow diagram illustrating the process of identification, screening, and inclusion of studies in the review.

The Methodological items for non-randomized studies (MINORS) instrument was independently used by two reviewers (IN, GS) to evaluate the quality of the included studies (Supplemental Table 2).¹⁵ A consensus was reached to address any discrepancies.

Results

Seven studies met the inclusion criteria for this systematic review, encompassing 260 patients and a total of 520 breasts. These studies are summarized in Supplemental Table 3, which outlines their designs, patient demographics, surgical techniques, follow-up periods, and key outcomes. Due to significant heterogeneity in study designs, the absence of control groups, and the lack of standardized tools for outcome measurement, including validated instruments such as BREAST-Q,¹⁶ a meta-analysis was not feasible. This absence of uniform patient-reported outcome measures and objective tools limited the ability to compare results across studies quantitatively and underscores the need for standardized methodologies in future research.

Indications and surgical techniques

The included studies evaluated the use of P4HB mesh in diverse clinical scenarios. Adams et al.^17,18 published two studies exploring the role of P4HB mesh in breast surgery. The first study evaluated¹⁷ 11 patients undergoing central mound mastopexy. The mesh was positioned to reinforce the lower pole and maintain breast projection. Measurements were conducted preoperatively and at 1, 3, 6, and 12 months postoperatively using three-dimensional breast scanning and manual techniques. The second study was a multicenter,¹⁸ prospective, single-arm observational study evaluating 62 patients undergoing mastopexy and reduction mammoplasty. The mesh was used in a hammock-like design to support the lower pole. Three-dimensional imaging was performed at pre-procedure, 30-day, 90-day, 6-month, and 12-month intervals to assess clinical efficacy.

Mallucci et al.¹⁹ investigated using P4HB mesh in 65 patients undergoing mastopexy with and without implants. In mastopexy alone (45 patients), the mesh was placed between the gland and the skin to support the lower glandular pole, minimizing lower pole descent. In augmentation mastopexy (20 patients), the mesh was sutured to the pectoralis muscle and chest wall fascia to stabilize submuscular implants.

In secondary augmentation, Buccheri et al.²⁰ examined 34 patients undergoing implant plane-switching from retropectoral to subglandular positions due to complications such as capsular contracture. The rectangular mesh was trimmed and divided diagonally into two triangular pieces, which were sutured to the pectoralis muscle to cover the implant's medial, superior, and superomedial aspects. Twelve patients required bilateral mastopexy, and one required a unilateral mastopexy for symmetry. The incision patterns for mastopexies were not specified in the article.

Bistoni et al.²¹ studied 72 patients who underwent primary or secondary augmentation mastopexy using P4HB mesh. All patients received smooth, round subfascial implants supported by the P4HB mesh. Advanced artificial intelligence (AI) software with three-dimensional reconstructions assessed the lower pole stretch. The percentage elongation of the lower pole arch—the curvilinear distance between the nipple and the inframammary fold—was calculated at 6 and 12 months postoperatively.

Complex revision surgeries were addressed by Tomouk et al.,²² who compared P4HB mesh and acellular dermal matrix (ADM) in 11 patients with soft tissue deformities in the medial cleavage area. Six patients received P4HB mesh, while five were treated with ADM. Both materials were intended to provide structural support during revision procedures targeting challenging contour deformities. Nair et al.²³ studied a smaller cohort of five patients undergoing revision surgeries for capsular contracture, where P4HB mesh was utilized as an internal support to prevent future lower pole sagging.

Clinical outcomes and observed patterns

The studies demonstrated varying outcomes regarding lower pole stability, ptosis correction, and complications. In the first Adams et al. study,¹⁷ significant improvements in breast shape and support were reported, with an average increase in the nipple-to-inframammary fold (N-IMF) distance of 8 mm (9.6 %) over 1 year (p = 0.003) and an increase in the sternal notch-to-lowest breast position (SN-LBP) distance of 13.9 mm (5.3 %; p = 0.03). Most changes occurred within the first 3 months, attributed to swelling reduction. The second Adams et al.¹⁸ study reported that at 1 year postoperatively, 67.9 % of patients had Grade 0 ptosis, 3.6 % had pseudoptosis, 25 % had Grade I ptosis, and only two patients had Grade II ptosis. Device-related adverse events were low, occurring in 8 % of patients and including nerve pain, breast swelling, ptosis, and asymmetry.

Mallucci et al.¹⁹ observed that in mastopexy alone, lower pole descent ranged from 0.52 % to 12.63 %, with a mean of 5.95 %, while augmentation mastopexy showed a descent ranging from 1.98 % to 15.46 %, averaging 6.66 %. The lower pole arc length increased by 7.11 % in mastopexy and 7.74 % in augmentation mastopexy, demonstrating the mesh's role in providing structural stability.

In the study by Bistoni et al.²¹ at 12 months, the average elongation of the lower pole was 8.04 %. Most of this stretch occurred within the first 6 months, with no statistically significant differences between 6-month and 12-month measurements. Notably, a significant correlation (p < 0.05) was found between implant size and lower pole elongation, with larger implants (>400 cc) associated with greater stretching, possibly reflecting the mesh's ability to support larger implants while mitigating excessive tissue deformation.

The study by Buccheri et al.²⁰ included 34 Caucasian patients with Fitzpatrick skin types I-III. The average age of the participants was 38.2 years (SD ± 10.438), with a mean BMI of 23.4 kg/m² (SD ± 2.826). The follow-up period averaged 12 months, ranging from 6 to 28 months. Patient satisfaction was assessed using a Visual Analog Scale (VAS), with scores of 9–10 indicating the highest level of satisfaction. Breast shape was rated 9–10 by 64.7 % of patients, while 79.4 % expressed similar satisfaction with breast size. Breast symmetry had the highest satisfaction scores, with 85.3 % rating it in the 9–10 range. Although scar appearance received slightly lower scores, 41.2 % of patients still rated it as 9–10, with an additional 23.5 % in the moderate range (VAS 3–5). Overall quality of life was rated 9–10 by 91.2 % of patients, reflecting the positive outcomes of the procedure.

In the study by Nair et al.²³ population had an average age of 46.2 years (SD ± 12.44), ranging from 33 to 66 years, and an average BMI of 22.4 (SD ± 2.83), with values ranging from 19.2 to 25.8. All participants were white, and the follow-up period averaged 15.34 months (SD ± 6.70), ranging from 4.36 to 22.57 months. Preoperatively, patients had an average Baker Grade Contraction score of 2.8 (SD ± 0.9189), which improved to 1 (SD ± 0) postoperatively. The most commonly used GalaFLEX sizes included 7.5 cm x 20.3 cm, 7.5 cm x 21 cm, and custom dimensions, such as 8 cm x 15 cm for one breast and 12 cm x 15 cm for the other, in asymmetric cases.

The study by Tomouk et al.²² involved 11 patients (ages 29–68, mean 43 years) undergoing revision breast augmentation with biological scaffolds in the medial cleavage area. Seven patients had multiple prior breast surgeries (2–6 procedures), with intervals ranging from 7 to 22 years since the first surgery and 6–22 months since the most recent one. None of the patients used tobacco or nicotine products. GalaFLEX® mesh was used in six cases and SurgiMend® ADM in five. Mastopexy was performed in eight patients. The reported follow-up period ranged from 3 to 5 years. A mean follow-up time was not mentioned, and satisfaction and surgical outcomes were not reported, apart from complications.

Reported complications were minimal overall. Mallucci et al. listed two adverse events: one infection and one case of acute seroma following strenuous physical activity. Buccheri et al.²⁰ reported no significant capsular contracture, implant rippling, or scaffold palpability during follow-up periods ranging from 6 to 28 months. Tomouk et al.²² recorded one case of bleeding requiring emergency surgery and one minor scar revision. Notably, no scaffold extrusion, infection, or redness were described across the studies.

Discussion

A crucial element of this synthesis involves scrutinizing the potential conflicts of interest revealed by the authors of the articles included in the analysis. The credibility of the systematic review's findings is intricately tied to the openness and dependability of these disclosures. We carefully examined the conflict-of-interest disclosures provided in the included studies throughout the review process. Out of all the examined studies, potential conflicts of interest were revealed. The disclosures exhibited a range of variations, encompassing financial connections with medical device manufacturers, advisory positions, and ownership of stocks. Considering how these revealed conflicts may have impacted the study results is imperative. Research funded by organizations vested in the outcomes can intentionally or unintentionally manipulate data interpretation, design, and reporting. This trend requires a cautious interpretation of the results, highlighting the importance of verifying and analyzing them independently.

One of the primary outcomes of aesthetic breast surgery is to achieve a stable and long-lasting outcome. Sometimes, factors such as poor tissue quality, multiple surgeries, or the use of high-volume breast implants could affect the result's stability and determine a quick ptosis relapse or pseudoptosis. Using a synthetic bio-compatible internal breast supporting system is becoming increasingly popular as a promising suspension method.²⁴ The utilization of polypropylene mesh to provide support to the breast during aesthetic breast surgery has been reported in the 1980s.¹⁰ Góes was among the first to document more predictable long-term outcomes using soft-tissue support material in mastopexy.^11,25,26

Furthermore, Góes advocated using a composite mesh incorporating non-degradable and biodegradable fibers instead of polyglactin mesh, characterized by a brief resorption time. According to the author, the prolonged permanence of the mesh granted more stability and reduced the burden of foreign materials.²⁵

Over the years, various synthetic mesh and biologically derived materials have been available. The ideal mesh should have mechanical and physical properties that allow high elasticity, following the movements of the breast tissue and maintaining adequate in-plane stiffness to hold the weight. The material should possess a high level of flexibility to achieve a breast that is supple, soft, and natural. Furthermore, an optimal equilibrium between durability, inflammation, biocompatibility, and integration is necessary, thus minimizing the risk of long-term infection or extrusion. Full integration and resorption of the mesh are critical points in avoiding its palpability, especially in low-BMI patients. At the same time, the mesh should not hinder breast physical examination or determine any artifact to mammography or other diagnostic techniques.^26,27 Finally, the device should be cost-effective to facilitate a steep learning curve. Nowadays, a mesh with such parameters is not available on the market. Both biological (e.g., ADMs) and synthetic meshes have pros and cons. Biological meshes have optimal integration and biocompatibility. However, the cost of biological meshes is elevated and often hardly compatible with an aesthetic surgery setting. On the other hand, synthetic meshes have a lower cost, which allows broader use and good biocompatibility but an increased risk of infection, exposure, poor integration, and palpability.

The P4HB might present many of the advantages of an optimal mesh. It is highly biocompatible and has a long resorption time, which provides stability over the healing phase. Moreover, it has a good integration capacity without any related radiological artifacts and an acceptable cost.

Usually, around 18–24 months, the body completely absorbs the mesh, resulting in tissue that is reported to be 3–5 times more robust than regular tissue.¹² According to the studies conducted by Adams et al.^17,18 and Mallucci et al.,¹⁹ the promotion of in-growth of vascularized tissue and consequent prolonged tissue strength determine the internal support effect. An immunohistochemical study reported that, at 7 months, the mesh is fully resorbed with minimal inflammation and substituted by vascularized connective tissue, mainly composed of type I collagen.^28,29

Therefore, the tissue strength increases significantly during wound healing, reaching its peak when P4HB dissolves. This increase in strength is essential during the stabilization phase of wound healing to reduce mechanical stress on the skin and scars and achieve a long-lasting result.³⁰

The reviewed studies considered different clinical settings ranging from primary mastopexy to secondary augmentation or augmentation/mastopexy. According to some studies above, the P4HB-mesh is positioned to provide internal support to soft tissues or implants like an internal bra.17, 18, 19, 20, 21 Furthermore, other authors used the P4HB-mesh as an additional implant coverage for areas at risk for implant visibility, like the medial poles.²² The high variability of surgical procedures among examined studies and even in the single studies does not allow for solid conclusions about the best clinical setting for P4HB mesh use.

Until now, there is no accordance regarding the best objective outcome to evaluate the stability of the result of a mastopexy with or without implants over time. In the examined studies, different proxies have been used to evaluate the descent of the lower pole. Among them, the distance between the sternal notch, the lower-pole arc length, the nipple-inframammary fold distance, and the percentage increase of these measurements are the most used. However, many different measurement systems have been used, including 3D imaging, 3D reconstruction software, and photographic analysis with measurement software.

According to Adams, the distance between the sternal notch and the inferior breast point remained relatively constant over the first year, with a 5.5 % increase (equivalent to 1.5 cm) observed through 3D imaging analysis.^17,18 This finding indicates a high level of stability in the lower pole of the breast. Malluci's research measured the lower pole stretch using two distinct measurements: lower pole descent, which is the percentage increase in vertical length between the nipple and the IMF between 6 weeks and 1 year after the surgery, and arc length increase, which is the percentage increase in curvilinear distance.¹⁹ The average drop of the lower pole was 5.95 %, accompanied by a 7.11 % rise in arc length. The values for the group with implant/mastopexy procedures were somewhat higher, namely 6.66 % and 7.74 %. The observed increase in stretching in the lower pole among the group with implants (7.11 % vs. 7.74 %) is expected due to the additional weight of the implant and the stretching of the tissues caused by its presence. The P4HB mesh may significantly reduce the occurrence of inferior and lateral malposition, mainly when used with a smooth implant, thus playing a crucial role in prevention.

Nonetheless, there is no consensus in the literature about the correct timing to consider a result of mastopexy as stable.³¹ Even though 1 year could be sufficient to observe an early ptosis relapse or pseudoptosis in patients with poor-quality soft tissues or heavy breast implants, the process can continue over the subsequent years, thus determining a short duration of the result.

The use of P4HB has been documented in the management of some complications arising after primary breast aesthetic surgery. Thus, Nair,²³ Buccheri1,²⁰ and Tomouk²² detailed using P4HB to correct many secondary issues, such as inadequate tissue coverage, misplacement of the pectoral muscle, and capsular contracture formation. Currently, using acellular dermal matrices (ADM) is very effective in enhancing implant coverage and minimizing problems in breast reconstruction.^32,33 In postmastectomy pre-pectoral implant placement, utilizing an acellular dermal matrix (ADM) or synthetic mesh to achieve complete or partial implant coverage effectively prevents capsular contracture animation deformity and wrinkling/rippling.34, 35, 36 In selected cases, especially in patients with thin soft tissue or low BMI, a combined approach involving both mesh scaffolds and autologous tissue (such as fascia flaps or fat grafting) has also been proposed to further reduce implant palpability and correct rippling, offering an additional layer of structural support.³⁷

Additionally, when ADM is placed between the detached lower edge of the pectoralis major muscle and the infra-mammary fold, it creates a suitable space for the final implant without requiring tissue expansion, thus avoiding displacement.³⁸ Therefore, ADMs in the context of secondary aesthetic breast surgery could be a viable option to prevent complications.³⁹ However, high cost could limit their application in the private setting.

The P4HB mesh may be regarded as a viable substitute for ADM since it is safe and cost-effective, with a low incidence of complications. The P4HB scaffold possibly offers improved mechanical stability to the implant, higher implant coverage, and enhanced protection against capsular contracture.

Another option to treat secondary complications of breast implants is polyurethane (PU)-coated implants. The qualities of the polyurethane foam significantly decrease various types of dislocations and capsular contracture, which are the primary reasons for further surgeries. However, these specific characteristics are the underlying source of problems associated with PU implants.⁴⁰ There will be no alterations in the location of the implant as a result of gravitational forces, as happens with silicone-coated implants. The positional stability of PU-coated implants could be advantageous, even though it is sometimes difficult to control. Furthermore, PU seems to reduce the incidence of capsular contracture in revisional surgery. The advantages of PU foam–covered implants include cost-effectiveness and the abovementioned benefits.⁴¹

However, when it comes to avoiding undesirable outcomes, it is inevitable to go through a learning process to manage PU-coated implants in cosmetic breast implant revision surgery effectively.

Moreover, polyurethane's progressive degradation may increase the capsular contracture rate over the years,^42,43 and the contentious issue with PU degradation, releasing possibly cancer-causing metabolites, resulted in the FDA rejecting the US marketing of polyurethane-coated implants.⁴⁴

Finally, the data on PU-coated implants are primarily derived from retrospective studies and only few prospective evidence are available hindering strong conclusions about their effectiveness.^45,41

P4HB mesh may be an alternative option to PU-coated implants or a substitute in countries like the US, where PU-coated implants are unavailable.

The evaluation of the efficacy of the P4HB mesh in the examined studies in terms of reduction of the implant-related complication rate has yet to be confronted with the ADMs or PU-coated implants. Furthermore, the studies' follow-up was generally limited, with the longest lasting approximately 3–5 years, even though a mean follow-up duration has yet to be evidenced.²² Most of the studies have a mean follow-up duration of 1 year, which could be inadequate to evaluate specific outcomes. Complications like capsular contracture or rotation in reoperative augmentations have an incidence in the prospective core studies between 2.4–14.8 % at 6 years and 14.5–24.4 % at 10 years,^46,47 with an increase of 1 % per year after the first 6 years. Rotation or malposition has an incidence of 2.4 %−9.1 % at 10 years.^46,47 A short follow-up can miss many of these events. Furthermore, the retrospective nature of most of the examined studies is prone to several biases, like selection, misclassification, and recall bias. Additionally, due to this study design, the authors do not consistently provide information on the number of patients lost to follow-up, further limiting the reliability of the findings.

Patient satisfaction is another relevant parameter to consider when dealing with the aesthetic surgery setting. Several instruments to register patient-reported outcomes (PROMs) have been developed recently. The most standardized and diffuse questionnaire used in breast surgery is the BREAST-Q.¹⁶ The main drawback of the BREAST-Q is that it is a time-consuming questionnaire, making it difficult to use in a private setting. However, it is the most validated tool available to evaluate PROMs. In some cases, the examined studies do not analyze the satisfaction outcomes^17,19,21, 22, 23 while other studies used non-standardized satisfaction outcome measures.^18,20

Regarding mesh-related complications, the P4HB mesh may have various advantages. The quick integration of tissues and monofilament construction provides high protection against infection. Contrary to ADMs, which often result in postoperative seromas⁴⁸ and redness in the breast,⁴⁹ no instances of red breast syndrome or routine postoperative seromas with P4HB were described. However, the reduced follow-up time does not allow for a conclusion on late adverse effects, even though some patients can report mesh palpability or nodules approximately 1 year after implantation.^18,23

Conclusion

In conclusion, P4HB meshes could be considered a valid option in many difficult-to-manage situations in aesthetic breast surgery. It can help deal with poor tissue quality and secondary implant surgery, particularly in countries where polyurethane is unavailable or as a more economical substitute for ADMs. Nonetheless, the data available in the literature are still insufficient to draw solid conclusions, and a higher quality of evidence is needed.

Based on the already accessible data, there is some evidence about the effectiveness and safety of P4HB in cosmetic breast surgery. However, the small number and diverse characteristics of clinical research, the absence of a formal control group, and the poor quality of evidence were significant limitations to this review. Additionally, variations in breast shape and volume across individuals pose considerable challenges to direct comparisons with a control group, and the problem is compounded by the short follow-up durations reported in six of the seven studies.

However, our systematic review might serve as an initial reference for further investigation, not only in the field of cosmetic breast surgery but also in reconstructive surgery.

Declaration of competing interest

The authors have no conflicts of interest to declare.