Nerve repair and reconstruction

Repair and reconstruction of injured peripheral nerves still belong to the most difficult reconstructive surgical problems. In spite of use of refined surgical techniques repair of a major nerve trunk in the upper extremity of adult patients does usually not result in recovery of tactile discriminative functions in the hand. Up to the age of 10-12 years, however, it is considered that the recovery of all aspects of sensory functions is optimal, but there is a lack of long-term follow-up in the medical litterature. These observations indicate that there is an important central nervous component in sensory recovery following nerve repair.

Thus, interest should be focused on peripheral as well as central nervous components involved in the repair process. Therefore, our research on nerve repair and reconstruction includes aspects on nerve repair techniques as well as aspects on the sensory relearning which is required during the rehabilitation phase.

On basis of several years of experimental animal research we have tested new repair techniques for median and ulnar nerve lesions in the human forearm. In a prospective randomised study we have compared conventional microsurgical nerve repair techniques with tubular repair where silicone tubes have been used to enclose the injury site. The functional recovery has been meticulously followed for a period of five years, using the Model Instrument for Documentation after Nerve Repair (Rosén 2003). There is a continuous ongoing recovery in sensory and motor functions over the whole five year period. Although neurophysiological parameters do not improve after two years there is an ongoing continuous sensory recovery also over the following three years indicating an important component of sensory relearning. After five years there is no statistically significant difference between the two groups regarding sensory functions, motor functions or discomfort, such as pain and paraesthesia, but with respect to cold intolerance there was a statistically significant difference in favour of the silicone tubes (Lundborg et al, 2004).

Silicone tube repair represents a prototype for tubular repair, however with a biomaterial which is non-irritable/inflammatory although not bio-resorbable. In the five year follow-up study of tubular nerve repair, silicone tubes were removed more than a year after the nerve repair. Surprisingly, there was almost no foreign body reaction around the silicone tube except some minor patchy areas with some macrophages in the capsule surrounding the silicone tube (Dahlin et al, 2001). When the tube was removed we could also see that there was a new nerve trunk bridging the former gap with clearly seen blood vessels on the surface of the formed nerve trunk. However, there is a need for develop new bio-resorbable tubes.

In collaboration with colleagues in Umeå (Hand Surgery) and Malmö (Orthopaedics and Obstetrics) our brachial plexus team also focus on brachial plexus lesions in adults and children. In follow-up studies the results of different repair and reconstruction techniques after brachial plexus lesions are studied. We also have continues follow-up of brachial plexus birth lesions with focus on occurrence of posterior dislocation in the shoulder showing that even up to 10% of children with brachial plexus birth lesion may have a posterior dislocation in the shoulder within one year of age. To decrease the incidence of brachial plexus birth lesions it is important to consider a large number of characteristics in both the mother and child. A collaboration has been initiated with obstetricians in Malmö and Stockholm to study such characteristics with the purpose to decrease the incidence of brachial plexus birth lesions.