Priority-Matching Correction Technique in Degenerative Lumbar Scoliosis

For Type 1 global coronal malalignment (GCM), TL/L curve makes the primary contri- bution on C7PL shifting. First, inserting pedicle screws bilaterally. Second, aggressively decreasing the magnitude of TL/L curve. Third, moderately leveling L4 endplate to pull the fusion segments to the middle line with hand pressure on the convexity of TL/L curve. If the correctability of the key curve was limited, the correction of the minor curve would be con- vergent. For Type 2 GCM, LS curve makes the primary contribution on C7PL shifting. First, releasing LS curve from the concave side using facetectomy after screws inserted. Second, performing L4-5 or L5-S1 trans- foraminal lumbar interbody fusion (TLIF) from the con- vexity of the fractional curve, with cages inserted at the concave side to assist deformity correction. Third, compressing the convexity of LS to horizontalize L4 endplate, followed by moderate manipulative reduction of TL/L curve to adjust intraoperative coronal balance.

In concave coronal malalignment (CM), the correction of the main curve improves the CM, thus we can talk about convergent corrective objectives. The ability to correct the CM depends on the correctability of the main curve. The need of three-column osteotomies in order to obtain correction of CM depends on the location and flexibility of the main curve. The correction of convex CM depends on the correction of the lumbosacral curve. The correction strategy will depend on many factors including the driver of the deformity, which should always be fused, but also the degeneration and stiffness of the compensatory curve which can lead to more extended fusion. The need of three-column osteotomies depends mainly on the stiffness of the lumbosacral curve.