A new nerve coaptation technique using a biodegradable honeycomb-patterned film

We developed a biodegradable poly-lactide (PLA) film with a honeycomb-patterned porous structure (honeycomb film). This study investigated the use of this film in neurorrhaphy. Three types of PLA film were tested following bilateral sciatic nerve transection and neurorrhaphy in 35 rats: 7- and 10-μm thick honeycomb films, and cast film with no porous structures. Initially, following two-stitch neurorrhaphy, 40 limbs (20 rats) underwent wrapping in 7- or 10-μm honeycomb film, cast film, no wrapping, or extra two-stitch neurorrhaphy (8 limbs each). Breaking strength was tested 2 days postoperatively. Another 30 limbs (15 rats) then underwent wrapping in 7- or 10-μm honeycomb film, cast film, no wrapping, or sham operation (six limbs each). Histological and functional analyses were performed 6 weeks postoperatively. Breaking strength was significantly higher for the 10-μm honeycomb film than for no wrapping (P = 0.013), although no significant difference was observed between the 7-μm honeycomb and no wrapping (P = 0.085). Breaking strength for the cast film was almost equal to that for no wrapping (P = 0.994). Extra two-stitch (four-stitch) neurorrhaphy was significantly stronger than all groups, except the 10-μm honeycomb group. No significant difference was observed between the 10-μm honeycomb and the four-stitch (P = 0.497). No negative effects on functional recovery were identified. No adhesions or inflammation were observed between the film and surrounding tissues in the honeycomb groups. Honeycomb film may offer a suitable reinforcing material for adhesion-free neurorrhaphy.