Nerve regeneration over a 25 mm gap in rat sciatic nerves using tubes containing blood vessels: the possibility of clinical application.

This study was undertaken to investigate the effect of including vessels in a tube used to promote nerve regeneration across a gap. A tube containing sural vessels was designed in a rat model and interposed between the proximal and distal stumps of a divided sciatic nerve, leaving a 25 mm gap. At 12 weeks, a few myelinated axons were seen at the most distal parts of regenerated nerves in 6 out of 10 rats, none of which evoked action potentials in the tibialis anterior muscle, but by 24 weeks all the rats had developed neural tissue in the tubes, which evoked action potentials in the muscle. The vessels within the tube enhanced nerve regeneration and its distance up 25 mm. This type of vessel-containing tube would be useful for the repair of divided human peripheral nerves with long gaps, almost equivalent to or slightly longer than the maximum length over which nerve fibres can regenerate through a unvascularised unmodified tube.