gms | German Medical Science

Lumbar spine fusion is acknowledged as the „gold -standard" for a wide variety of spinal diseases like spondylolisthesis, instabilities, stenosis, de-novo scoliosis and failed back surgery syndromes.

But in discogenic pain with or without disc herniation fusion is considered to address the pain from the altered disc itself. Therefore spinal arthroplasty appears to be an alternative chiefly because the preservation of segmental mobility is believed to be beneficial to prevent a phenomenon recognized as adjacent level degeneration.

Reviewing the literature reveals, that the biomechanics of the adjacent segment in lumbar fusion is altered toward hypermobility, increase of facet joint pressure and increase of intradiscal pressure which may lead to the degeneration.

The incidence is reported between a rate of 1.2% per year and 3.9% per year and is reported to be most frequent in posterior or postero-lateral fusions, more seldom in antero-posterior procedures and most seldom in anterior only procedures.

But data of the natural course of disc degeneration where missing until a study of Hasset et al 2003 showing a similar rate of 4% adjacent disc degeneration per year in patients without spinal surgery. Furthermore Kim et al 1991 found, that the biomechanical changes in a segment adjacent to a degenerated segment are similar to a segment adjacent to a fuse segment.

This leads to the conclusion that there is no prove that adjacent level degeneration is initiated or worsened with spinal fusion and this findings should be taken into consideration when considering spinal arthroplasty instead of spinal fusion.