In the treatment and control groups before treatment and at 0 , 6 , 12 , and 24 months after treatment , the VAS scores were : 6.5 + / - 1.9 and 6.4 + / - 1.6 ; 4.6 + / - 1.3 and 4.6 + / - 1.7 ; 4.8 + / - 1.3 and 4.8 + / - 1.2 ; 4.6 + / - 1.2 and 6.6 + / - 1.6 ; and 6.5 + / - 1.6 and 6.5 + / - 1.3 , respectively .