Table 4.

Preclinical and experimental studies on facial nerve reconstruction by artificial nerve guidance conduits.

Study	Year	Conduit material	Cells/factors	Species	Defect size or technique	Regrowth time span (weeks)	Outcome
Cui et al. [32]	2014	Collagen	Neurocytokines CNTF and bFGF	Minipig	35 mm	24 weeks	(i) Favorable mechanical properties (ii) May promote facial nerve regeneration effectively
Inada et al. [33]	2007	Polyglycolic acid collagen blend	None	Human	n/a	24 weeks	(i) Functional and morphological regeneration
Matsumine et al. [34]	2014	Polylactic acid, nonwoven	None	Rat	7 mm	13	(i) Comparable ability of autografts to induce peripheral nerve regeneration
Liu et al. [35]	2013	Chitosan	Nerve growth factor presented in microspheres	Rabbit	10 mm	13	(i) Sustained release of nerve growth factor can significantly improve facial nerve defect repair
Shi et al. [36]	2012	Polylactic-co-glycolic acid	Neural stem cells (NSC)	Rat	Facial nerve transection	12	(i) Nerve action potential amplitude and axonal area were significantly greater in the NSC compared to an empty control group
Tan et al. [37]	2009	Silk fibroin-chitosan blend	None	Rabbit	10 mm	8	(i) Successful regeneration of the facial nerve
Guo and Dong [38]	2009	Chitosan	Neural stem cells (NSC)	Rabbits	10 mm	12	(i) Comparable results to an autograft in 10 mm facial nerve defects