COMPENSATORY MECHANISMS AND THE EFFECT OF AGE ON SAGITTAL BALANCE IN SPONYLOLISTHESIS: AN ANALYSIS UTILIZING THE PELVIC RADIUS TECHNIQUE
Mokhtar SA, McCombe PF, Sergides IG, Saravanja DD, White GW, *Sears WR.
Podium presentation at Spine Society of Australia
Annual Scientific Meeting
Sydney, April 29th 2012
Annual Scientific Meeting
Sydney, April 29th 2012
Abstract
INTRODUCTION
Few studies have investigated the effect of age on spino-pelvic sagittal alignment and none have examined this effect in patients with spondylolisthesis. Knowledge of the effects of age on alignment in the degenerating spine may aid understanding of the compensatory mechanisms, which patients adopt. This study investigates correlations between age and measures of spino-pelvic alignment in patients with isthmic and degenerative spondylolisthesis, and whether compensation mechanisms, which patients use in sagittal imbalance, differ as they age.
METHODS
A cross-sectional, observational study of pre-operative radiographs, in which measures of spinal sagittal alignment were acquired from the pre-operative radiographs of 382 consecutive patients with spondylolisthesis (isthmic-85 and degenerative-297) using the pelvic radius technique (Reference). Pearson’s univariate correlations were tested between age and the measured parameters. Compensation mechanisms were explored by examining correlations between spino-pelvic parameters – for all patients and after stratifying into 3 age groups (<45-years, 45-60 and >60-years)
RESULTS
No significant correlations were found between age and any parameters in the degenerative spondylolisthesis patients. In the isthmic spondylolisthesis patients, correlations were found between age and total lumbo-pelvic lordosis (r=-0.45) and between age and pelvic angulation (r=0.44). In the <45-years, isthmic patient subgroup, a strong correlation (-0.58, p=0.02) was found between the focal lordosis at the slip level and the lordosis above. Correlations between total lumbo-pelvic lordosis and pelvic angulation were observed in both the degenerative spondylolisthesis (r=-0.74, P <0.001) and isthmic spondylolisthesis (r=-0.69, p<0.001) patients.
CONCLUSION
The hyperlordosis observed in younger patients may represent the primary compensation mechanism for a focal loss of sagittal alignment, while an increase in pelvic angulation (pelvic retroversion) appears to be a secondary compensation mechanism that is adopted by older patients, with stiffer spines. It is postulated that knee-flexion and/or ankle-extension may represent a third compensation mechanism, which is used when the limit of pelvic extension is reached.
REFERENCE
Jackson RP, McManus A. Spine. 1994;19:1611S-1618S.
INTRODUCTION
Few studies have investigated the effect of age on spino-pelvic sagittal alignment and none have examined this effect in patients with spondylolisthesis. Knowledge of the effects of age on alignment in the degenerating spine may aid understanding of the compensatory mechanisms, which patients adopt. This study investigates correlations between age and measures of spino-pelvic alignment in patients with isthmic and degenerative spondylolisthesis, and whether compensation mechanisms, which patients use in sagittal imbalance, differ as they age.
METHODS
A cross-sectional, observational study of pre-operative radiographs, in which measures of spinal sagittal alignment were acquired from the pre-operative radiographs of 382 consecutive patients with spondylolisthesis (isthmic-85 and degenerative-297) using the pelvic radius technique (Reference). Pearson’s univariate correlations were tested between age and the measured parameters. Compensation mechanisms were explored by examining correlations between spino-pelvic parameters – for all patients and after stratifying into 3 age groups (<45-years, 45-60 and >60-years)
RESULTS
No significant correlations were found between age and any parameters in the degenerative spondylolisthesis patients. In the isthmic spondylolisthesis patients, correlations were found between age and total lumbo-pelvic lordosis (r=-0.45) and between age and pelvic angulation (r=0.44). In the <45-years, isthmic patient subgroup, a strong correlation (-0.58, p=0.02) was found between the focal lordosis at the slip level and the lordosis above. Correlations between total lumbo-pelvic lordosis and pelvic angulation were observed in both the degenerative spondylolisthesis (r=-0.74, P <0.001) and isthmic spondylolisthesis (r=-0.69, p<0.001) patients.
CONCLUSION
The hyperlordosis observed in younger patients may represent the primary compensation mechanism for a focal loss of sagittal alignment, while an increase in pelvic angulation (pelvic retroversion) appears to be a secondary compensation mechanism that is adopted by older patients, with stiffer spines. It is postulated that knee-flexion and/or ankle-extension may represent a third compensation mechanism, which is used when the limit of pelvic extension is reached.
REFERENCE
Jackson RP, McManus A. Spine. 1994;19:1611S-1618S.
