Development of New Surgical Mesh Geometries with Different Mechanical Properties Using the Design Freedom of 3D Printing

The use of various rapid prototyping technologies in connection with the development of new medical products offers a newfound freedom of shape design that allows direct influence on the mechanical properties. Melt electrowriting (MEW) offers the possibility to redesign surgical meshes and their geometry, creating different geometries with different mechanical properties without changing the material properties. The adaptation of the mechanical properties plays an important role in the transplantation of medical products into a host tissue to mimic the mechanical behaviour of soft tissues as well as possible. To improve the adaptability of surgical meshes for pelvic organ prolapse (POP), wavy fibres and wavy fibre meshes were designed and printed using an optimised MEW printing process to mimic the mechanical behaviour of vaginal tissue. The mechanical examination based on design of experiments methods shows a widely varying mechanical range that can mimic different elastic soft tissues with mesh deformations up to 100 % elongation, a Young's modulus ranging from 50 to 400 N/mm2 and a variable toe region. An adaptation of the geometry to the soft tissue of the human vaginal wall shows a sufficient fitting and can be improved by further adjustments of the geometry. The printed meshes have a porosity and effective porosity of over 70 % and are lightweight or ultra-lightweight. By combining adapted mechanical properties with good porosity and weight, 3D printed meshes made of polycaprolactone (PCL) with a wavy fibre geometry are an interesting solution that may improve the outcomes of the pelvic surgery to treat the POP.