Do sandwich vertebral bodies increase the risk of post-augmentation fractures? A retrospective cohort study.

ABSTRACT

Until now, there have been only a few retrospective studies that focused on the outcomes of sandwich vertebral bodies (SVBs). This is a long-term retrospective cohort study to investigate the SVBs. We found that although patients with SVBs had a relatively high risk of developing new fractures after VA, the incidence rate of new fractures was not significantly different from that of the control group. However, the statistical power of this study was very limited. Therefore, and because the refracture rate in these patients is substantial, routine long-term monitoring of patients after VA for osteoporosis is strongly recommended. BACKGROUND: Sandwich vertebral bodies (SVBs) are intact unaugmented vertebral bodies between two previously augmented vertebrae. Until recently, only a few studies have reported the outcomes and strategies for SVBs. This retrospective cohort study aimed to describe the clinical features and incidence of new fractures in patients with SVBs. METHODS: The clinical data were collected from 179 patients with 237 symptomatic osteoporotic vertebral compression fractures who underwent vertebral augmentation (VA). Among them, 23 patients with 24 levels of SVBs were included. Spinal radiographs (X-ray and CT) of all patients were evaluated prior to surgery 1 day after primary VA and during follow-up. RESULTS: All patients successfully underwent PKP with an average follow-up period of 21.48 months. Asymptomatic cement leakage occurred in four patients (17.4%), and eight patients (34.8%) developed new fractures following primary PKP, including four sandwich, six adjacent, four remote vertebral fractures, and one re-collapse of cemented vertebrae. The incidence of new fractures in the SVB and control groups was 16.7% (4/24) and 13.0% (6/46), respectively, but there was no significant difference. CONCLUSIONS: Although patients with SVBs had a relatively high risk of developing new fractures after VA, the incidence rate of new fractures was not significantly different from that of the control group. However, the statistical power of this study was very limited. Therefore, and because the refracture rate in these patients is substantial, routine long-term monitoring of patients after VA for osteoporosis is strongly recommended.