The Transition from Experimental Data to Clinical Practice Using P4HB Mesh in Ventral Hernia Repair

Despite early success with synthetic permanent mesh in ventral hernia repair due to its tensile strength and durability, it has been associated with long-term complications like mesh infection, erosion and chronic pain.¹ In an attempt to address the limitations of synthetic mesh first biologic meshes were developed as acellular matrices that better resisted infection, promoted revascularization and minimized longterm foreign body reaction.² However, this type of mesh is extremely expensive and has demonstrated increased recurrence rates without really affecting complications.³ Therefore, Poly-4-hydroxybuturate (P4HB) was designed as a type of biosynthetic mesh implant in an attempt to combine the strength of a synthetic mesh with an increased bacterial resistance due to its biocompatible byproducts.^4,5

Using this type of longterm resorbable mesh in clinical scenarios however still raises the one million dollar question whether the repair is robust enough to prevent hernia recurrence after the mesh has been fully resorbed? This is especially true for clean, non-contaminated surgical fields. In this paper, the authors compare the longer term results of using a P4HB mesh with an anti-adhesive visceral protective layer during laparoscopic repair in a pig model.⁶ Different types of hernia defects were created, 8 cm diameter with defect closure, and both 4 and 8 cm hernias without defect closure; all were treated with a circular 15 cm diameter P4HB-ST mesh. A little bit surprisingly, all repaired hernia sites exhibited similar mechanical strength as well as histological properties, independent of both hernia size, defect closure, and follow-up time (48 and 72 weeks after implantation). In relation to these interesting findings, some relevant issues have been not been addressed with regard to the clinical use of this type of mesh. As this paper specifically addresses the use of this resorbable mesh in a laparoscopic intraperitoneal onlay fashion (IPOM), it seems difficult to understand how synthetic mesh does show longterm recurrences based on limited mesh-tissue ingrowth, and defect closure is now strongly advised, even more for larger defects, while in this study both 4 and 8 cm defects were not closed, but the strength of all hernia defect sizes were similar.⁷ Furthermore, to use a mesh of 15 cm diameter for defects of 8 cm diameter is obsolete in clinical setting. The results of this paper should therefore be interpreted with caution. The authors do not really tackle this issue, but for surgeons these elements are essential before being able to balance the strength of synthetic intraperitoneal meshes with the positive, mostly longterm, beneficial effects of resorbable polymers. It is also important to correlate these promising experimental data with the limited clinical data available so far, showing a clinical recurrence rate of 10% after short-medium follow-up in open hernia repair studies.^8,9 Does this have to do with patient characteristics, human hernia characteristics or both? It certainly provides an extra element in the discussion as surgeons predominantly use the biosynthetic meshes in clean-contaminated and contaminated fields in which prevention of mesh infection is more important than recurrence rate. There is no evidence available that can support the advantages of resorbable synthetic meshes over the use of synthetic or biological meshes in clean surgical fields, mostly due to lack of good data.¹⁰ More clinical studies are needed, followed by randomized controlled trials and prospective registries in humans with a sufficiently long follow-up period, to reveal the potential advantages in clinical practice.

Disclosure statement

No potential conflict of interest was reported by the author(s).