There were no significant differences for the primary outcome measure at one month ( mean pain score @ ( SD @ ) and mean change from baseline -@ ( SD @ ) in epidural steroid injection group versus @ ( SD @ ) and -@ ( SD @ ) in gabapentin group ; adjusted difference @ , @ % confidence interval -@ to @ ; P = @ ) and three months ( mean pain score @ ( SD @ ) and mean change from baseline -@ ( SD @ ) versus @ ( SD @ ) and -@ ( SD @ ) , respectively ; adjusted difference @ , -@ to @ ; P = @ ) .