In pelvic floor reconstructive surgery, the use of non-degradable, synthetic materials predominates. Among these, polypropylene meshes, noted for their "monofilament, macropore, and lightweight" characteristics, are particularly prevalent. However, given the pelvic floor's dynamic nature, the optimal material for such meshes should ideally combine flexibility and elasticity to accommodate movement with sufficient strength for reliable support. Thermoplastic Polyurethane (TPU), known for its inherent elasticity and biocompatibility, emerges as a promising alternative for crafting vaginal meshes. TPU-based meshes could offer superior mechanical properties for pelvic floor applications, including enhanced flexibility and greater resistance to mechanical stress compared to polypropylene variants. The desired characteristics of an ideal mesh include biocompatibility, minimal inflammatory response, adaptability to tissue requirements, and durability against elongation until supportive connective tissue formation. Additive manufacturing (AM) or 3D printing, the process of constructing complex three-dimensional objects layer by layer from a digital model, has found extensive applications in the medical field. This includes uses in orthopedics, tissue engineering, and the fabrication of medical devices, allowing for the customization of medical products and instruments to fit individual anatomical and tissue specifications through advancements in technology and material science.
This study aims to develop a 3D-printed thermoplastic polyurethane (TPU) mesh and assess its performance in terms of adhesion formation, tissue integration, and biomechanical properties using a rat model.

In this research, 24 in-bred female virgin Wistar Hannover rats underwent a procedure in which either a 3D-printed TPU mesh or a polypropylene lightweight mesh (3x2 cm) was placed on the perifascial (onlay) position of the abdominal wall covering intact peritoneum. This was achieved through a 3cm vertical incision. After a period of 12 weeks, the meshes were removed for evaluation. The study included macroscopic examination to score adhesions and histopathological analysis to assess tissue reaction. Biomechanical analysis focused on uniaxial tensile strength and elasticity, conducted using the Instron 10000e series mechanical testing system in accordance with ASTM standard D882-12. Statistical analysis involved the Mann–Whitney U test for ranked variables and Fisher’s exact test for categorical variables.

Early postoperative complications, including hematoma and surgical site dehiscence, were noted in both the thermoplastic polyurethane (TPU) and polypropylene (PP) groups, occurring in 33.3% (4 cases) of TPU and 25% (3 cases) of PP subjects. Both materials achieved satisfactory tissue integration, with comparable levels of connective tissue development and vascularization observed. The prevalence of multinucleate giant cells ranged from moderate to high in the meshes of both types, with TPU meshes experiencing more pronounced cell infiltration. Immunohistochemical evaluation disclosed significant and intense staining for TGF Beta in the TPU mesh, in contrast to the PP mesh, which exhibited widespread but moderate staining after a 12-week period. The TPU mesh displayed exceptional elasticity and maintained structural integrity under mechanical stress, evidenced by a breaking elongation of 150% and a tensile strength of 30 N/cm, thereby preserving effective porosity.

Our study underscores the advantages of 3D-printed thermoplastic polyurethane (TPU) meshes for pelvic floor reconstruction, showcasing notable benefits over conventional polypropylene (PP) meshes. Although the occurrence of early postoperative complications was comparable between TPU and PP meshes, the heightened inflammatory response observed in TPU meshes warrants a closer examination of their biocompatibility. However, the exceptional elasticity and robust mechanical properties of TPU, evidenced by its elongation at break and tensile strength, indicate its superior capacity to meet the pelvic floor's dynamic requirements without sacrificing durability.
The advent of 3D printing technology in the creation of TPU meshes offers the prospect of bespoke surgical interventions, designed to align with the specific anatomical and biomechanical profiles of individual patients, thereby enhancing the prospects of surgical success and patient contentment. Despite the encouraging implications of our findings for the application of TPU in pelvic floor restoration, they highlight the imperative for additional investigation. This includes the necessity for broader and human-centric studies to thoroughly evaluate the long-term biocompatibility, safety, and performance of TPU meshes in a clinical milieu. Our research thus marks a significant stride towards the realization of personalized, patient-centric advancements in the field of pelvic floor reconstructive surgery.

The superior elasticity, tissue compatibility, and tensile strength of the 3D-printed thermoplastic polyurethane (TPU) mesh render it a promising material for pelvic floor reconstructive surgery. The positive outcomes of our study advocate for additional research into the utilization of TPU meshes in pelvic floor procedures, especially those that demand customization to meet the distinct anatomical and biomechanical needs of individual patients.

Lambertz A, Van Den Hil LC, Schöb DS, Binnebösel M, Kroh A, Klinge U, Neumann UP, Klink CD. Analysis of adhesion formation of a new elastic thermoplastic polyurethane (TPU) mesh in comparison to polypropylene (PP) meshes in IPOM position. Journal of the mechanical behavior of biomedical materials. 2016 Jan 1;53:366-72.
Yuan M, Hu M, Dai F, Fan Y, Deng Z, Deng H, Cheng Y. Application of synthetic and natural polymers in surgical mesh for pelvic floor reconstruction. Materials & Design. 2021 Nov 1;209:109984.
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