Avulsion injuries to the brachial plexus and the value of motor reinnervation by ipsilateral nerve transfer.

1. It is now generally accepted that time between the injury and its reconstruction is a crucial determinant of the functional result. In long-standing brachial plexus lesions, atrophy of the denervated muscles progresses until reinnervation becomes impossible or can only produce a minor, clinically unimportant result. Therefore, it is important to perform an early surgical exploration within 3 months of the injury. However, at that time, it is often dicult to decide on the best surgical strategy, as it is sometimes impossible to determine the potential for, and possible extent of, spontaneous recovery. 2. The number of motor neurones available for nerve ®bre regeneration is usually signi®cantly reduced in brachial plexus lesions. Therefore the remaining capacity for reinnervation should be directed exclusively to the most important muscle targets. This produces a better clinical outcome than attempting less concentrated reinnervation of many muscles, which is likely to restore no muscle function of practical bene®t. 3. Reinnervation by foreign nerves from within or outside the brachial plexus (neurotisation), either from the ipsilateral or the contralateral side, is not only an important technique for the treatment of fresh lesions. When combined with muscle transplantation, it is also of value in the management of long-lasting motor de®cits (Frey et al., 1990). 4. In a proximal lesion like a brachial plexus injury, useful reinnervation of the muscles of the forearm and hand is exceptional. Although the nerve ®bres can regenerate the long distance down the arm, the target muscle ®bres may irreversibly atrophy during the time taken for this process. Thus, in order to restore forearm muscle function, a functional muscle transplant has to be considered as a new target for the successfully regenerated nerve. 5. Shortening of the distance for nerve regeneration should be performed whenever possible: thus a muscle transplant might be inserted in a more proximal, extra-anatomical position. 6. Avoiding the use of nerve grafts excludes further factors which reduce the functional outcome. For