At 6 months after operation , the interbody fusion rate was 76.19 % ( 16/21 ) in trial group and 43.48 % ( 10/23 ) in control group , showing significant difference ( 2 = 3.60 , P = 0.03 ) ; at last follow-up , the fusion rate was 95.24 % ( 20/21 ) in trial group and 65.22 % ( 15/23 ) in control group , showing significant difference ( 2 = 4.38 , P = 0.02 ) .