**5. Complications**

Common complications seen with surgical mesh use in breast reconstruction include infection, adhesion formation, capsular contracture and skin flap necrosis. Post operative adhesions can form after any type of surgery and carry increased risk of mortality and morbidity [59]. They increase operating time, as dissection can prove challenging, whilst can lead to patients requiring further surgeries to resolve [59]. There is currently poor understanding of the mechanism of adhesion formation with research suggesting the three main mechanisms include inhibition of extracellular and fibrinolytic degradation systems, an inflammatory response being induced by which cytokines and transforming growth factor-beta (TGF-beta) are produced, and tissue hypoxia, where vascular endothelial growth factor (VEGF) is expressed at increased levels [60]. Meticulous surgical technique is currently the gold standard prevention for adhesions, with liquid and solid anti-adhesive agents also able to be used, with limited evidence in laparoscopies [61].

Use of surgical mesh increases risk of site infection due to a prosthesis being introduced into the body, with risk post mastectomies being as high as 53% [62]. Notably, expander implants carried increased infection rates, compared to reconstructions using autologous tissues [63]. At present it is difficult to determine whether use of biological mesh in implant reconstruction leads to more complications [64], thus we must consider prevention of these complications. One trend to do this, is infection prophylaxis via antibiotics, alcohol-based skin preparation and pocket washout which feature in UK national guidance [15].

Capsular contracture commonly occurs post breast surgery due to an excessive fibrotic reaction to the foreign body known as the implant in the breast (**Figure 4**) [65], via an inflammatory response [66]. As a result, the collagen capsule that surrounds the implant contracts, distorting the breast tissue, and is categorised using the Baker classification system [67]. Class I describes a natural looking breast, II is a breast with minimal contracture, II, moderate contracture and IV, severe contracture [68] however recent literature reports poor reliability of this classification tool [69]. Capsular contracture can be caused by microbial biofilm formation [67], silicone or smooth implants, subglandular implant placement and prior radiotherapy to the breast [66]. At present, many techniques have been trialled to prevent and reduce risk of capsular contracture with breast implants post operatively, including use of biological and synthetic meshes adjunctively, anti-inflammatory and immune modulating drugs, anti-fibrotic drugs and antibiotics [65]. Physical modification of implants has been examined extensively and so research is now pointing towards pharmacological approaches in the hope that this will better reduce risk of capsular contracture.

**Figure 4.**

*Inflammatory response and foreign body reaction leading to capsular contracture [65].*

Skin flap necrosis is another complication seen after implant reconstructions. Post mastectomy skin flap necrosis can lead to issues with wound management, infection of the implant and can look aesthetically displeasing [70]. The necrosis may be partial or full thickness and management can vary accordingly. Partial skin flap necrosis may require local wound care, whilst full thickness may need surgical debridement; it is known that adjunctive therapy such as chemotherapy or radiotherapy can be delayed if there is poor wound healing as a result of skin flap necrosis [70]. Risk factors for skin flap necrosis can include smoking, hypertension, increased breast volume [71–73]; modification of these pre-operatively may aid in reducing risk.

The long-term effects of the reconstructed breast, including breast symmetry, capsular contracture, infection rate, patient satisfaction, revisions and explantation rate are being evaluated in order to ascertain the long-term benefits and cost implications.

#### **6. Future development**

Surgical matrices are continually evolving, to suit the growing surgical requirements. Hybrid mesh, a mix of biological and synthetic materials are being explored further in the literature [27]. The combination is thought to combine the benefits of both materials, whilst reduce any complications they bring. Researchers believe that the biological part of the hybrid mesh, will protect the synthetic part from infection, and it is currently used in hernia repairs [27]. Hybrid meshes are seen as a cost-effective advancement in the field, with tensile strength of a synthetic mesh, but enabling for resorbable material to be used [74]. At time of writing, the literature presents us

#### *Meshes in Implant-Based Breast Reconstruction: The Science and Technology DOI: http://dx.doi.org/10.5772/intechopen.112995*

with limited evidence of this mesh in clinical practice, however no differences have been found in complication and recurrence rates between patients where synthetic and hybrid meshes were used [75]. Further research is required to fully evaluate the long-term effects in patients.

Biological meshes, being animal derived, bring into question some ethical issues, notably surrounding religious beliefs [76]. Animal derived products have been used in surgery for many years and we know that as a society composed of multiple religions and faiths, that animal products may spark important conversations. Porcine is the most common form of animal derived mesh, with bovine being the most accepted by religious groups in England [76]. This study highlighted the importance of clinicians having knowledge of the origins of their surgical meshes used, and how their patients' religious beliefs, if any, may translate across.

3D printed meshes may aid in alleviating this issue surrounding religious beliefs for biological mesh. Synthetic materials which are both biodegradable and biocompatible may be used in future 3D printed meshes, and this method would allow for personalised meshes to be quickly created, specific to each patient [77]. 3D printed meshes have already been considered in vaginal surgery [78] and hernia repairs [79], and are now being considered for use in breast reconstruction [80]. They offer an innovative new technology for reconstructive scaffolds with personalised breast shapes and sizes able to be created at a low cost, with the pore structure of the mesh providing access for fat injection at the implant site postoperatively [81]. One paper has shown 3D printed scaffolds as able to regenerate breast glandular tissue [82], an exciting advancement for their use in breast reconstructive surgery; as such, 3D printed scaffolds could be used to facilitate flapless nipple reconstruction when seeded with autologous adipose tissue and implanted subdermally at the site of reconstruction [83].

Drug loaded meshes are another recent advancement in the surgical field. Multiple studies have explored local antibiotic loading into mesh for infiltration into the surgical repair site [84–86]. Antibiotic delivery directly into the surgical site, reduces and prevents related infection [84], with antibiotics loaded onto the mesh surface [87]. Rifampicin, vancomycin and ciprofloxacin are some of the many antimicrobials which have been trialled [85, 86, 88]. To date, antibiotic loaded mesh has been explored for use in hernia [89] and vaginal repairs [78]. Looking ahead, this may enable for further development of loaded meshes in surgery; notably, stromal cells have been loaded onto a breast scaffold in breast reconstructive surgeries which led to a longer lasting graft, with increased vascularisation [90]. Whilst antibiotics can be loaded onto meshes, meshes can also gain antimicrobial properties via newer, alternative methods such as metallic particles [77], which have shown promise in recent studies [91–93].
