Biological performance of a degradable poly(lactic acid‐ε‐caprolactone) nerve guide: Influence of tube dimensions

Abstract

One of the ways to reconstruct a nerve defect is to use a biodegradable nerve guide. The aim of this study was to establish a nerve guide constructed of an amorphous copolymer of lactic acid-caprolactone. A pilot study was set up to elucidate the effect of the tube dimensions on nerve regeneration. Four types of nerve guides, with internal diameters ranging from 1.12-1.23 mm and wall thicknesses ranging from 0.34-0.68, were tested for this purpose. We evaluated the biodegradation, foreign body reaction and nerve regeneration by light microscopy, after three different implantation times (1, 2, and 3 months). After 2 months, we observed that all types of nerve guides had changed from a transparent to an opaque and swollen state, and that they had lost their strength. The foreign body reaction was characterized by the presence of giant cells and fibroblasts surrounding the degrading nerve guide. From this pilot study, we conclude that nerve guide type 1, with an internal diameter of 1.23 mm and a wall thickness of 0.34 mm, can ensure nerve regeneration in the case of a 1-cm gap in the sciatic nerve of the rat. Nerve guides types 3 and 4, with relatively small lumens, show nerve compression due to a more pronounced swelling of the degrading tube.

In vitro degradation and biocompatibility of poly(DL‐lactide‐ϵ‐caprolactone) nerve guides

“…19 The first results with this poly(96L/4D-lactide) as osteosynthesis material were promising. 19 Nerve guides constructed of poly ( 50 / 50 ( 85 / 15 L / D ) lactide-⑀-caprolactone) possessed good properties for bridging a 10-mm gap in the sciatic nerve of the rat, 20,21 and resulted in better functional nerve recovery compared to autologous nerve grafts. 22,23 The nerve guide degraded completely within 1 year, 24 without the formation of slowly degrading biomaterial fragments.…”

Long-term evaluation of functional nerve recovery after reconstruction with a thin-walled biodegradable poly (DL-Lactide-?-caprolactone) nerve guide, using walking track analysis and electrostimulation tests

“…The use of a biodegradable nerve guide composed of an amorphous copolymer of DL-lactide and -caprolactone [p(DLLA--CL)] has proven to be effective. [4][5][6] Nerve regeneration across a 10-mm nerve gap, using a biodegradable nerve guide, was faster and qualitatively better when compared with nerve regeneration through an autologous nerve graft. 7 Moreover, this nerve guide degrades fast and completely within 1 year.…”

Evaluation of functional nerve recovery after reconstruction with a poly (DL-Lactide-ε-Caprolactone) nerve guide, filled with modified denatured muscle tissue

“…We chose to reconstruct a 1.5-cm nerve gap with a nerve guide filled with MDMT, in order to evaluate whether a longer gap could be successfully bridged, and whether the results obtained after reconstruction using this technique are comparable to those after reconstruction of the ''standard gap length'' (i.e., 1 cm) without MDMT, which was evaluated in all previous studies. [8][9][10][11]16,20,[22][23][24] In our opinion, the addition of modified denatured muscle tissue inside a nerve guide (group B) would create a three-dimensional (3-D) structure, providing the possibility to reconstruct a longer nerve gap. Therefore, a 50% longer nerve gap was chosen.…”

“…Due to the presence of muscle tissue inside the nerve guide, there is less tendency for the nerve guide to collapse. 20 Recently we evaluated different preparation techniques of denatured muscle tissue, 21 aiming at an open structure of the extracellular matrix (ECM) and an intact basement membrane.…”