A cut peripheral nerve can be repaired by either suturing the two nerve stumps together directly or by interposing a nerve graft between the two stumps. Several factors such as the patient's age, type of injury, and proximity of the lesion will influence the functional results. In our own experiments we have encased the two nerve stumps in various chambers intentionally leaving a short gap between the nerve stumps. In these chambers neurotrophic factors will accumulate and in a prospective randomized clinical trial it has been demonstrated that the chamber principle has some advantages as compared to established technique. Other experiments utilizing predegenerated experimental nerve grafts have demonstrated that regenerating axons enter these grafts more rapidly than in ordinary nerve grafts.