Correct answer:

Operative repair using an operating microscope is usually required. If a section of the nerve has been lost such that approximation is not possible, the nerve is freed proximally, or even moved from its original position to a new anatomical plane where more length will be available. For example, the ulnar nerve can be transposed from the posterior to the anterior aspect of the elbow joint to allow compensation for a distal loss of nerve substance. After nerve suture, recovery cannot be expected to take place until the time for regeneration has been allowed for, at the rate of 1 mm/day. Eventual recovery will seldom be full.