Lightning Podiums: Smorgasboard - Room 802B

Presented by: R. Lafage

Author(s):

R. Lafage(1), S. Pesenti(2), D. Stein(1), J. Varghese(3), J. Elysee(1), H.J. Kim(1), L. Lenke(4), F. Schwab(1), V. Lafage(1)

(1) Hospital for Special Surgery, New York, NY, United States
(2) Hopital d'Enfants de la Timone, Marseille, France
(3) SUNY Downstate Medical Center, New York, NY, United States
(4) Columbia University Medical Center, New York, NY, United States

Abstract

Background: The relationship between pelvic morphology and the shape of the lumbar lordosis remains poorly defined. It was our hypothesis that the shape of the lumbar lordosis and its relationship with the pelvis could be described using anatomic parameters, independently of posture.

Purpose: To describe the variation of lumbar segmental lordosis in an asymptomatic adult population, to elucidate the impact of PI value on segmental lordosis; and describe the changes in lordosis apex position depending upon PI value.

Methods: One hundred and nineteen (119) asymptomatic volunteers between 18 and 79 years old were prospectively enrolled in the study. Several radiographic parameters, such as segmental and cumulative lordosis, were measured. . Cumulative lordosis was defined as the angle between L1 and S1, proximal lordosis was the angle between L1 and the superior endplate of L4; and distal lordosis was the angle between the superior endplates of L4 and S1. Stratification by pelvic incidence (PI) was performed (low (< 45°), average (45-60°) and high (>60°) PI) and the proportion of distal and proximal lordosis was compared between groups.

Results: Mean age was 50.7 years old; there were 81 women and 38 men. In the whole cohort, proximal lordosis accounted for 38% of the total lordosis, whereas the distal lordosis accounted for 62%. Pelvic incidence was significantly correlated to proximal lordosis (r=0.546, p< 0.001) but not to distal lordosis (r=0.087, p=0.346). Stratification by PI showed that proximal lordosis significantly increased across PI groups (16.6° vs 21.6° vs 30.1°, p< 0.001) whereas distal lordosis remained constant (34.8° vs 36.7° vs 35.9°, p=0.581).

Conclusions: This study sheds light on the relationship between pelvic morphology and the sagittal shape of the lumbar spine in an asymptomatic adult population. Pelvic incidence strongly influences the proximal part of the lumbar lordosis, whereas the distal part is independent of pelvic anatomy. The proximal part of the lumbar spine has the most variability across individuals and appears to accommodate to pelvic morphology (incidence). This relationship should be taken into consideration for surgical planning if a personalized and patient-specific lumbar shape is sought, rather than simply global lordosis matched to pelvic incidence.

Distribution of Segmental lordosis according to PI