De. Gelb et al., AN ANALYSIS OF SAGITTAL SPINAL ALIGNMENT IN 100 ASYMPTOMATIC MIDDLE AND OLDER AGED VOLUNTEERS, Spine (Philadelphia, Pa. 1976), 20(12), 1995, pp. 1351-1358
Study Design. A radiographic evaluation of 100 adult volunteers over a
ge 40 and without a history of significant spinal abnormality was done
to determine indices of sagittal spinal alignment. Objectives. To det
ermine the sagittal contours of the spine in a population of adults ol
der than previously reported in the literature and to correlate age an
d overall sagittal balance to other measures of segmental spinal align
ment. Summary of Background Data. Previous studies of sagittal align m
ent have focused on adolescent and young adult populations before the
onset of degenerative changes that may affect sagittal alignment. Meth
ods. Radiographic measurements were collected and subjected to statist
ical analysis. Results. Mean sagittal vertical axis fell 3.2 +/- 3.2 c
m behind the front of the sacrum. Total lumbar lordosis (T12-S1) avera
ged -64 degrees +/- 10 degrees. Lordosis increased incrementally with
distal progression through the lumbar spine. Lordosis at L5-S1 and the
position of the apices of the thoracic and lumbar curves were most cl
osely correlated-to sagittal vertical axis. Increasing age correlated
to a more forward sagittal vertical axis with loss of distal lumbar lo
rdosis but without an increase in thoracic or thoracolumbar kyphosis.
Conclusions. The majority of asymptomatic individuals are able to main
tain their sagittal alignment despite advancing age. Loss of distal lu
mbar lordosis is most responsible for sagittal imbalance in those indi
viduals who do not maintain sagittal alignment. Spinal fusion for defo
rmity should take into account the anticipated loss of lordosis that m
ay occur with age.