Patients were assessed by visual analogue scale ( VAS ) ( Boonstra et al. , Int J Rehabil Res 31:165 -169 , 2008 ; Price et al. , Pain 17:45 -56 , 1983 ) pain score for back and leg pain , and the Oswestry Disability Index questionnaire ( ODI ) ( Smeets et al. , Arthritis Care Res ( Hoboken ) 63 : S158-S173 , 2011 ) .