Silicone rubber tubulization in peripheral sensory nerve reconstruction: An experimental study in rabbits

Abstract

Silicone rubber (polydimethyl siloxane) tubes are used clinically in peripheral nerve reconstruction. A disadvantage of this procedure is that the material often has to be removed owing to its mechanical properties. The aim of our study was to investigate the healing of reconstructed sensory nerves tubulized by silicone rubber in an animal model. In our experiments, we reconstructed the saphenous nerves in 27 rabbits. In series 1 (n = 12), silicone rubber tubes were slid over a nerve suture without a gap. In series 2 (n = 12), silicone rubber tubes were slid over a 10-mm nerve gap. In series 3 (n = 12), conventional suturing was performed in the collateral saphenous nerves of the animals of the series 1. Epineurial suturing was performed. Three other collateral nonoperated saphenous nerves served as controls. The healing was studied after 3, 6, and 12 months. Morphometric analysis of the regenerating axons was performed by using our new method for quantification of nerve fibers in cross sections stained by immunohistochemistry and using confocal laser scanning microscopy. Data analysis was carried out using a software program especially developed for this purpose. Our results showed in the silicone procedures that at 12 months significantly fewer axons per fascicle area were present compared with conventional suturing. However, mean axon diameters in the distal nerve stump of the silicone procedures did not differ significantly compared with the conventional suturing procedure. The ratio of total axon area to total fascicle area in the distal nerve stumps of the silicone procedure without gap was significantly smaller compared with the conventionally sutured nerve. The percentage outgrowing axons from the proximal nerve stump into the distal one in the silicone rubber procedure without gap was 57%. This was significantly higher than in the silicone rubber procedure with 10-mm gap (48%). However, in conventional suturing, the percentage of outgrowing axons (99%) was significantly higher than in both tubulization procedures. It appeared that tubulization by silicone rubber of sutured nerves without gap did not enhance axon regeneration. Conventional suturing gave significantly better results. If a gap was present, the use of a silicone rubber tube was preferable to non-suturing.

Local delivery of glial cell line–derived neurotrophic factor improves facial nerve regeneration after late repair

“…[30][31][32][33][34] Similarly, it has already been determined that an entubulated end-to-end coaptation has no effect on nerve regeneration. 35 Continuous release of nanogram quantities of GDNF on the distal suture of autologous nerve grafts over a period of 6 weeks gave opposite results in the two groups of the study, i.e., immediate or 7-month delayed repair. In the immediate repair group, no, and even a tendency of worse results, were obtained with GDNF.…”

Biocompatibility of biodegradable semiconducting melanin films for nerve tissue engineering

“…This provided the motivation for studying the tissue–biomaterial response of melanin with the sciatic nerve. Silicone was chosen as a control material since it generates a mild, short-term immune response [16] and has been used as a biomaterial for peripheral nerve reconstruction in previous studies [17]. Melanin samples were prepared by drop casting 100 μL of 8% (w/v) melanin in DMSO solution onto smooth PDMS substrates.…”

Luminal Fillers in Nerve Conduits for Peripheral Nerve Repair

“…80,81 Lundborg et al 82 showed this operational distance could be extended to 15 mm in rat sciatic nerve if synthetic filaments were inserted into the tubes. Eight polyamide filaments with a diameter of 250 m, placed inside silicone tubes with an inner diameter of 1.8 mm, helped sensory fibers bridge the gap and extend into the distal nerve segment, supported by a positive pinch reflex and positive staining for neurofilaments in the distal segment.…”