Optimal Correction of Adult Spinal Deformities Requires Restoration of Distal Lumbar Lordosis

Abstract

Purpose. The aim of this study is to analyze results according to postoperative pelvic incidence-lumbar lordosis (PI-LL) mismatch in the management of adult spine deformity (ASD) patients. Recently, it has been reported that in addition to lumbar lordosis amount, lordosis repartition between its proximal and distal parts was crucial. Methods. We enrolled 77 consecutive ASD patients who underwent posterior spinal fusion and deformity correction between 2015 and 2018. On preoperative and 1-year follow-up radiographs, we analyzed different parameters such as L1-S1 lumbar lordosis, L1-L4 proximal lordosis (PLL), L4-S1 distal lordosis (DLL), pelvic tilt (PT), sagittal vertical axis (SVA), and PI-LL mismatch. Comparisons were performed according to postoperative PI-LL mismatch (defined as “aligned” when PI-LL was <10°). The relationship between lordosis distribution and postoperative alignment status was investigated. Results. On the whole series, average lumbar lordosis, SVA, and PI-LL improved (28.2° vs.43.5°, 82 vs. 51 mm, and 26°vs. 14°, all p < 0.001 , respectively). On the other hand, PT remained unchanged (30° vs. 28°, p > 0.05 ). 35 patients were classified as “aligned” and 42 as “not aligned.” Patients from the “aligned” group had a significantly lower PI than patients from the “not aligned” group (52° vs. 61°, p = 0.009 ). Postoperative PLL was not different between groups (18° vs. 16° p > 0.05 ), whereas DLL was significantly higher in the “aligned” group (31° vs. 22°, p = 0.003 ). PI-LL was significantly correlated to DLL (rho = 0.407, p < 0.001 ) but not with PLL (rho = 0.110, p = 0.342 ). Conclusions. Our results revealed that in ASD patients, postoperative malalignment was associated with a lack of DLL restoration. “Not aligned” patients had also a significantly higher pelvic incidence. Specific attention must be paid to restore optimal distal lumbar lordosis in order to set the amount and the distribution of optimal postoperative lumbar lordosis.

Efficacy of Varying Surgical Approaches on Achieving Optimal Alignment in Adult Spinal Deformity Surgery

“…Similarly, in our study, we found an ALIF at L5-S1 to more effectively match the Roussouly shape, while also improving proportionality in GAP. Likewise, Yilgor et al , 31 as well as further follow-up studies, have shown the importance of restoring proper distribution of lordosis within the L4-S1 segment on both lumbopelvic realignment and mechanical complications 32 . A study investigating the location of PSO on the apex and distribution of LL highlighted the impact on lower versus upper PSOs on both apex and distribution, without significant effects on specific Roussouly shape 33 .…”

“…Likewise, Yilgor et al, 31 as well as further follow-up studies, have shown the importance of restoring proper distribution of lordosis within the L4-S1 segment on both lumbopelvic realignment and mechanical complications. 32 A study investigating the location of PSO on the apex and distribution of LL highlighted the impact on lower versus upper PSOs on both apex and distribution, without significant effects on specific Roussouly shape. 33 The results of our study communicate a similar message, demonstrating a PSO at L3 or L4 had the greatest improvement on PT and PI-LL, with no correlation overall to Roussouly shape.…”

Lumbar Lordosis Distribution in Asymptomatic Adult Volunteers: A Systematic Review

“…Although there was a statistical difference in LDI among the Roussouly types, DLL in all types was approximately 30° to 40° [4]. Pesenti et al proposed that DLL should be preserved or restored around 36° to reduce the risk of PJF [17].…”

How Does Gravity Influence the Distribution of Lordosis in Patients With Sagittal Malalignment?

“…This understanding can guide osteotomy selection and the restoration of the proportionate balance between the PI–LL and distal/proximal LL. 32 , 33 While lumbar lordosis has been shown to decrease with age, there is disagreement about where that decrease occurs. Non-invasive biomechanical measurements of healthy volunteers performed by Dreischarf et al 34 demonstrated an age-related decrease in LL, but through the mid-lumbar spine proximal to the apex of lordosis.…”