Are prebent rods ideal: a radiological analysis of lumbar lordosis after single level MIS TLIF at L3-4, L4-5, and L5-S1

Fusion surgery increases spine stiffness and can modify biomechanics and sagittal spinopelvic parameters. Restoration of sagittal balance is a key issue in lumbar fusion surgery. Inadequate sagittal plane correction has been associated with adverse postoperative outcomes. Thus maintainence or restoration of the sagittal plane spinal alignment forms an important aspect of the lumbar fusion surgery.

An important step of surgical planning involves the understanding of segmental contributions of different levels in the sagittal alignment of the spine. Majority of lumbar lordosis is present at the caudal 2 motion segments. The distribution of the lordosis in the lower (L4-S1) and upper (L1-L3) arcs is important as it alters the distribution of loads. Thus, a maldistribution of lordosis may result in mechanical complications in the post-operative period.