Adjacent segment degeneration following spinal fusion of vertebral fractures in paraplegic patients

Abstract

The effects of adjacent segment degeneration (ASD) after spinal fusion of vertebral fractures have previously not been demonstrated in patients with trauma-related paraplegia. The aim of this study was to evaluate the role of ASD in patients with paraplegia caused by vertebral fractures and to observe whether there is adifference between unilateral or combined spinal fusion in long-term results regarding the degeneration of cranial or caudal adjacent spinal segments. Atotal of 111 paraplegic patients with an average age of 45years who underwent spinal fusion of vertebral fractures were observed in aretrospective longitudinal study with afollow-up period of 4years. Conventional X‑ray images and magnetic resonance imaging (MRI) scans were used to assess the ASD in the adjacent free vertebral segments cranial and caudal to the spinal fusion using the following elements: ventral spondylophytes, intervertebral space, intervertebral disc signal in MRI, posterior spondylophytes, facet joint arthrosis, bone bridging and ossification of the anterior longitudinal ligament. Additionally, the classification by the American Spinal Injury Association (ASIA) impairment scale and spinal cord independence measure version3 score were surveyed. The 4‑year incidence of radiographically detectable ASD was 3-12 % in this study. The majority of ASDs were observed in the cranial segments adjacent to the interbody fusion. The dorsoventral spinal fusion showed the least effects on the adjacent segments. In conclusion, aconcept of prompt surgery using short dorsoventral segment fusion carried out by an interdisciplinary paralysis center is recommended. The role of natural degeneration processes and whether they are influenced by iatrogenic manipulation through the vertebral stabilization is unclear. For this reason it is important to further investigate strategies for ASD reduction in the future to ensure the best possible treatment success including the lowest degree of additional impairments for this special patient group.