These data provide both validation and st and ards for other users and indicate the power of the instrument for detecting change in sample population s. CONCLUSIONS The  ODI  remains a valid and vigorous measure and has been a worthwhile outcome measure .
The behavior of the instrument is incompletely understood , particularly in sensitivity to real change
STUDY DESIGN The Oswestry Disability Index ( ODI ) has become one of the principal condition-specific outcome measures used in the management of spinal disorders .
This review is based on publications using the ODI identified from the authors ' personal data bases , the Science Citation Index , and h and search es of Spine and current textbooks of spinal disorders .
OBJECTIVES To review the versions of this instrument , document methods by which it has been vali date d , collate data from scores found in normal and back pain population s , provide curves for power calculations in studies using the ODI , and maintain the ODI as a gold st and ard outcome measure .
SUMMARY OF BACKGROUND DATA It has now been 20 years since its original publication .
More than 200 citations exist in the Science Citation Index .
Can psychological traits predict the outcome of lumbar disc surgery when anamnestic and physiological risk factors are controlled for? Results of a prospective cohort study.
In a prospect i ve study 122 patients with herniated lumbar disc pre-operatively completed psychological question naires .  Surgical outcome was evaluated 12 months post-operatively mainly by a composite clinical overall score ( COS ) , and by its separate elements . Anxiety ( HAD-A scale ) and psychosomatic symptoms ( MSPQ ) had predictive value : fewer symptoms favoured a satisfactory overall outcome , and vice versa . The HAD-A Scale had a predictive power of poor ( ppp ) and satisfactory ( pps ) outcome of 28 and 81 % , respectively . Correspondingly , for the MSPQ , the ppp and pps were 42 and 85 % . Anamnestic and biological variables ( including fibrinolytic variables : ECLT and PAI-1 ) predicted 20 % of the outcome . By adding all psychological variables the prediction increased only to 24 % , but the HAD-A Scale and the MSPQ were still significant . The results suggest that in order to further improve prediction of outcome , future studies should combine biological variables sensitive to the mental state of the patient , with psychometric assessment
These data provide both validation and st and ards for other users and indicate the power of the instrument for detecting change in sample population s. CONCLUSIONS The  ODI  remains a valid and vigorous measure and has been a worthwhile outcome measure .
The behavior of the instrument is incompletely understood , particularly in sensitivity to real change
STUDY DESIGN The Oswestry Disability Index ( ODI ) has become one of the principal condition-specific outcome measures used in the management of spinal disorders .
This review is based on publications using the ODI identified from the authors ' personal data bases , the Science Citation Index , and h and search es of Spine and current textbooks of spinal disorders .
OBJECTIVES To review the versions of this instrument , document methods by which it has been vali date d , collate data from scores found in normal and back pain population s , provide curves for power calculations in studies using the ODI , and maintain the ODI as a gold st and ard outcome measure .
SUMMARY OF BACKGROUND DATA It has now been 20 years since its original publication .
More than 200 citations exist in the Science Citation Index .