Pelvic incidence (PI) is a static anatomic reference. ⢠Postural variation influences the mobile lumbar spine but Lumbar. Lordosis (LL) is commonly referenced ...
Influence of posture on pelvic and lumbar parameters : Comparison between the standing, sitting and supine positions. A preliminary study. Olivier Gille, Thomas Chevillotte, Derek T Cawley, Houssam Bouloussa, Simon Mazas, Soufiane Ghailane, Marion Petit, Louis Boissière, Ibrahim Obeid , Jean Marc Vital Institut de la Colonne Vertébrale Bordeaux, France
Introduction • Pelvic incidence (PI) is a static anatomic reference. • Postural variation influences the mobile lumbar spine but Lumbar Lordosis (LL) is commonly referenced only from standing erect lumbar radiographs.
Objective • Have other habitual positions such as sitting or lying supine an effect on the PI-LL relationship? • The objective is to analyze the relationship between lumbar lordosis (LL) and pelvic parameters in standing, sitting and supine positions.
Methods • Radiographs of 15 asymptomatic volunteers aged 18 to 50 years were analyzed to calculate pelvic and lumbar parameters in 3 positions. • Mean values and standard deviations were calculated for each parameter and compared using ANOVA. • Correlations were obtained using Spearman’s test.
Methods
Results • PI did not change throughout the series of positions.
Results
Standing PI = 68° PT=24° SS=44° LL=54° Sitting PT=47° SS=21° LL=13°
Lying PT=20° SS=48° LL=52°
Results
Standing PI = 68° PT=24° SS=44° LL=54° Sitting PT=47° SS=21° LL=13°
Lying PT=20° SS=48° LL=52°
Results PI (°)
PT (°)
SS (°)
LL (°)
Standing
49.3 ± 8,1
12.1 ± 6,3
37,1 ± 6.3
54.8 ± 9.8
Sitting
48.7 ± 7,9
37.7 ± 10.4
11.3 ± 10.8
15.9 ± 14.6
Supine
50.4 ± 6,7
9.5 ± 5.1
41± 7,2
50.2 ± 9.6
Mean values of spinopelvic parameters (degrees ± SD) LL/PI
LL/SS
PI/SS
PI/PT
Standing
0,57*
0,67**
0,63*
0,54*
Sitting
0,68*
0,80**
0,23
0,43
Supine
0,72**
0,9**
0,84**
0,72*
Correlations of PI/LL (r=0.72), LL/SS (r=0.9) and PI/SS (r=0.84) are strongest in supine position.
Correlation coefficients between spinopelvic parameters and lumbar lordosis (Spearman’s correlation coefficient)
Conclusion • While PI remains constant, orientation of the sacrum and lumbar spine change significantly throughout habitual positions, particularly in sitting. • Lordosis adjustments during spinal fusion procedures according to PI are fundamental even in patients with little physical activity.
• No conflict of interest
