An Experimental Study on the Regeneration of Rabbit Trigeminal Nerve: Nerve Graft and Entubulation with e-PTFE Menbranes

This study was designed to evaluate the ability of the injured trigeminal nerve to regenerate in the bone, and to compare the axonal regeneration following the nerve graft and nerve tubulization with GTR membrane. Fourteen rabbits were divided into 3 groups as follows : not repaired(Gc), Entubulation(G₁), and nerve graft(G₂) after partial resection of inferior alveolar nerves in the mandibular canals. The neuro-fibrotic tissues regenerated in the nerve gaps were prepared for histomorphologic examination by special staining with Hematoxylin & Eosin, Luxol-fast blue, Bodian's Masson-trichrome. The regenerated axons were examined with Toluidine blue staining and Transmission electronmicroscopy(TEM).

The injured mandibular nerve presented a regenerative capacity across 7 cm defect, and tubular repairs with GTAM produced histomorphologic regeneration of neural axons and mini-fascicles in 16 weeks. This investigation, however, showed a finding that autogenous nerve graft was inferior to tubulization in the histomorphologic assessment. The group of nerve graft disclosed less organized neural tissue(mini-fascicles) with more fibrovascular collagenous tissues.

Nerve injury resulting a gap which cannot be repaired by primary neurorrhaphy needs grafts or intrpositional tubular nerve guides. The e-PTFE membrane or tube can be used as a good conduit or sheath for nerve regeneration without adhesion of connective tissues, while the grafted nerves in the mandibular and bony ingrowth. Electrophydiologic examination and qualification of the regenerated axons are recommended to evaluate the substantial recovery following the nerve repair modalities.