Regeneration of the recurrent laryngeal nerve using in situ tissue engineering

The recurrent laryngeal nerve (RLN) is one of the most difficult nerves to regenerate functionally.(1)-3)) We report the animal experiment on regeneration of the RLN using in situ tissue engineering technique with a novel artificial nerve conduit-a woven polyglycolic acid (PGA) tube coated with collagen. The animal experiment was performed using 12 adult beagle dogs divided into 3 groups. In group I (n=6), 10 mm of the left RLN was excised. This gap was bridged with a woven PGA tube coated with collagen (5mm in diameter and 20mm in length). In group II (n=3), 40 mm of the nerve was excised and the gap was bridged with a PGA tube (5mm in diameter and 50mm in length). In group III (n=3), 10 mm of the nerve was excised and the gap was bridged with the nerve auto-graft. In order to estimate morphological and functional recovery of the nerve, not only the vocal cord movement but also the axonal transport and muscle action potential were examined. The RLN was morphologically and functionally regenerated in 4 dogs of the group I. In group II and III, functional recovery of the RLN was not observed. The PGA tube may be useful for regeneration of 10mm gap of the RLN.