There were no significant differences for the primary outcome measure at one month ( mean pain score 3.3 ( SD 2.6 ) and mean change from baseline -2.2 ( SD 2.4 ) in epidural steroid injection group versus 3.7 ( SD 2.6 ) and -1.7 ( SD 2.6 ) in gabapentin group ; adjusted difference 0.4 , 95 % confidence interval -0.3 to 1.2 ; P = 0.25 ) and three months ( mean pain score 3.4 ( SD 2.7 ) and mean change from baseline -2.0 ( SD 2.6 ) versus 3.7 ( SD 2.8 ) and -1.6 ( SD 2.7 ) , respectively ; adjusted difference 0.3 , -0.5 to 1.2 ; P = 0.43 ) .