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 .
External transpedicular fixation test of the lumbar spine correlates with the outcome of subsequent lumbar fusion.
External transpedicular fixation was applied to the lower lumbar spine in a prospect i ve study on 42 patients with chronic low back pain combined with suspected instability of the lumbar segments ; the diagnosis was failed disk surgery , spondylolisthesis , and degenerative disk disease . The aim was to realign the involved segments , to restore disk height , and to record changes in pain and performance during the external fixation test .  Pain was recorded on a visual analog scale , and performance was assessed using the Oswestry disability score . As independent observer assessed the test and treatment results . Twenty-nine patients experienced relief of pain and performed better in the fixator ; they were subjected to anterior interbody fusion , the external frame being kept as a stabilizing device for an additional four months . Twenty-two patients have had follow-up evaluations for two years . One and two years after successful lumbar fusion , significantly ( p < 0.02 ) better pain and performance scores were recorded ; the results of lumbar fusion corresponded to the preoperative fixation test . A temporary external fixation test may be a useful procedure in patients considered for subsequent spondylodesis
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 .