Different conduits in peripheral nerve surgery.

A considerable amount of research is being undertaken regarding the possibility of bridging loss of nerve substance with different guiding tubes, in order to improve functional outcome, reduce the surgical time, and reduce damage at donor nerve sites. A review of the literature and personal research allows us to state that: for short gaps, biological tubes (autologous veins) may give good results and also allow chemotactic attraction with selective arrangements of motor and sensory axons. Gaps longer than 1 cm do not allow tropism and are associated with failure to support axonal regrowth. Artificial biodegradable conduits still show results that are controversial; they may give good results provided that the material of which they are made is perfectly tolerated. Empty tubes, longer than 8-10 mm, besides being deprived of the chemotactic attraction, may collapse or be partially reabsorbed and replaced by scar. Probably in the near future biological or biodegradable tubes, containing laminin-like substances or muscle scaffold, will allow us to bridge increasingly large defects in nerves.