Technology

Torbjörn Mathisen, PhD

“TIGR® Matrix was developed to take advantage of the process whereby mechanical load induces remodeling of soft tissue, termed dynamic remodeling. After initial wound closure, the increasing compliance of the mesh results in a gradual transition of load from the mesh to the tissue. Long-term strength retention combined with increased compliance over time allowing remodeling of early reconstructed tissue opens up new opportunities in soft tissue repair.“

Mechanics

This design was developed to compensate optimally for the soft tissue’s lack of strength during each phase of wound-healing (closure, granulation and remodeling).
¹ Accordingly, the mesh degrades in several stages, each with different characteristics, described below.

Degradation and healing stages

Multistage mechanics are achieved by arranging two fibers with different degradation characteristics in an interlocking knitting pattern.

1. Strength and stability of the mesh is high in the initial wound-healing phases (closure and granulation).
2. Macroporosity throughout the mesh allows for good integration during granulation.
3. As the granulation phase transitions into the reconstruction phase, the extensibility of the mesh gradually increases.
4. Increased mesh extension when tissue stretch during reconstruction stimulates the remodeling of tissue.
5. The result of this dynamic reconstruction is a more structured, and hence stronger, connective tissue.

Materials

The family of polymers used in the mesh is well known in the surgical community for its resorbability and biocompatibility since the 1970s. At first glance, visually the two fibers appear quite similar, but their resorption characteristics differ significantly.

Fast resorbing fiber
The fast-resorbing fiber, making up approximately 40% of the matrix by weight, is a copolymer of glycolide, lactide, and trimethylene carbonate. It loses its mechanical strength after 2 weeks and is fully absorbed after 4 months.

Slow resorbing fiber
The slow-resorbing fiber, making up approximately 60% of the matrix by weight, is a copolymer of lactide and trimethylene carbonate. This fiber maintains its mechanical strength for 6 months and is absorbed after approximately 36 months.

Process

Both fibers degrade by bulk hydrolysis. After degradation the fibers are excreted by the human body through natural means. The figure below depicts these metabolic pathways.

Why Multifilament?

TIGR® Matrix is a multifilament mesh making it more pliable, flexible with a greater tensile strength when compared with monofilament meshes, which have a less complex fabric structure. These multifilament properties are transferred to TIGR® Matrix giving it superior handling characteristics enabling it to adapt willingly to underlying structures.

Non-twisted multifilament and integration

Non-twisted fibers allow integration of tissue not only through the open pores in the mesh but also in between each fiber of the TIGR® Matrix.

Porosity in warp-knitted fabrics

TIGR® Matrix is made of warp-knitted multifilament fibers giving it its unique structure. The small space between fibers will rapidly absorb blood due to capillary forces and later widen to give place to new tissue and blood vessels.³

Sterilization

TIGR® Matrix is sterilized with ethylene oxide (EtO) and is for single use only.

Packaging

TIGR® Matrix is packed in a double-pouch system to ensure sterility and to protect it from degradation.

• Inner pouch (sterile barrier)
  • The mesh is sterile.
  • Made of Tyvek® and polyethylene.
• Outer pouch (moisture barrier)
  • The outer pouch prevents moisture from coming into contact with the mesh.
  • The atmosphere in the outer pouch is extremely dry.
  • Made of aluminum.

1. Schultz S. et al. 2005, World Wide Wounds; Kingsnorth N. et al. 2013, Management of Abdominal Hernias; Junge U. et al. 2001, Hernia

2. Three-year results from a preclinical implantation study of a long-term resorbable surgical mesh with time-dependent mechanical characteristics H. Hjort, T. Mathisen, A. Alves, G. Clermont, J. P. Boutrand, Hernia, 16(2):191–197, 2012