Development of a nerve stretcher for in vivo stretching of nerve fibres

Abstract

Axons in vitro respond to mechanical stimulus and can be stretched mechanically to increase their rate of growth. This type of accelerated growth under the influence of tensile forces alone appears independent of chemical cues and growth cones. The stretch-growth of axonal tracts ex vivo and their transient lengthening have been discussed in literature extensively; however; evidence of in vivo investigations is scarce. Stretching axons, although practical ex vivo, is more challenging in vivo due to the difficulties of applying in situ axial tensile forces. Here, a technique has been developed to apply axial tensile forces to a peripheral nerve in vivo. A device has been constructed, called a Nerve Stretcher, which makes use of negative gauge pressure to pull sectioned nerve stumps in a confined nerve prosthesis. This article presents the development of this device and a discussion of the methodology used to hold sciatic nerve stumps in a T-shaped nerve prosthesis. The findings of this study will form the basis of future nerve-stretch growth studies.