Lumbar lordosis correction loss following lateral lumbar interbody fusion for adult spinal deformity

Although multilevel lateral lumbar interbody fusion (LLIF) with posterior column osteotomy (PCO) can achieve the similar effect as pedicle subtraction osteotomy (PSO) and the incidence of rod fracture (RF) is low, the risk of RF still remains. We noticed that correction loss often precedes RFs. To evaluate the correction loss after surgery in adult spinal deformity (ASD) patients, we retrospectively analyzed the CT scans of 89 ASD patients (average 71.5 years) with a minimum 2-year follow up. The intervertebral disc (IVD) angle from T12 to S1 were measured, comparing those with a decrease of 5° or more in lumbar lordosis (LL) at 2 years (correction loss group, n = 23) to those without a decrease (non-correction loss group, n = 63). The IVD angles in the L2-3, L4-5, L5-S1 showed significant differences immediately after surgery and at 1 year after surgery. RF incidence was 25.8% (23/89 cases). LL correction loss more than 5° was associated with RF (p < .001, OR = 7.28). The LL correction loss showed a distributed pattern with a decrease in each IVD angles. LL correction loss was closely associated with RF and can be seen as a danger signal of RF, so additional support should be considered to prevent correction loss and RF.