Purpose To analyze the serial changes of the lumbar sagittal alignment from preop. to final follow-up and to evaluate the role of the posterior spinal instrumentation, especially, short level fusion in correction and maintenance of the lumbar sagittal alignment in degenerative lumbar disease.
Materials and Methods Various lumbar sagittal profiles such as lumbar lordosis(LL), lordosis above, within and below instrumentation(LAI, LWI, LBI), horizontal vertebra and sacral inclination were serially measured in 54 patients whose radiographs at preop., intraop., immed. postop. postop. 2wks and final follow up(>1 yr) were completely equipped.
Results Intraop. posture, instrumentation itself and interbody fusion could not increase the LL and LWI sufficiently irrespective of the length of fixation. LWI was decreased compared with preop. values irrespective of length of fixation, while interbody fusion has a great role in maintaining the LWI. Loss of LWI was overcompensated at the segments above instrumentation in 1 or 2 levels fixation while compensation has not occurred in longer fixations.
Conclusions The longer the fixation, the more correction could be obtained. However, maintenance of this correction is more difficult in longer fixations. Prudent consideration should be taken in restoring sufficient lumbar lordosis and maintenance for favorable long term results.
