[Effects on the adjacent segment after spinal fusion and instrumentation]

This paper reviewed the literatures about the pathology at the segments adjacent to the fusion segments. The hypertrophic degenerative arthritis of the facet joints and spinal stenosis were the most common pathologic conditions. The pathology usually occurred at the upper segment in the patients of spinal fusion; and the lower segment would also show degeneration in those of instrumentation. The reason lied mainly in the increased stress at the adjacent segment after surgery and the change of segmental motion pattern. Symptoms usually developed within the first 5 years after fusion. Diagnosis depends on the clinical manifest and X-ray examination. Surgical intervention should be indicated if the conservative therapy failed, and decompression and fusion were most commonly applied.