Sandwich vertebra | Radiology Signs

Sandwich vertebrae occur due to increased sclerosis (bone density) at the vertebral endplates with a relatively lucent (normal density) central portion of the vertebral body. This radiologic pattern on spine radiographs is classically seen in benign adult autosomal dominant osteopetrosis, a disorder characterized by defective osteoclastic bone resorption leading to abnormally dense, brittle bones. Clinically, patients may present with bone fragility, fractures, and other features of osteopetrosis.

Why is it called so?

The name “sandwich vertebra” reflects the visual appearance on imaging, where the dense sclerotic endplates resemble the “bread slices” of a sandwich, and the less dense central vertebral body resembles the “filling,” thus creating a layered pattern reminiscent of a sandwich.

Pathophysiology

In osteopetrosis, defective osteoclastic resorption causes excessive bone deposition and sclerosis, especially at the vertebral endplates. This results in a marked contrast between the densely sclerotic endplates and the relatively normal cancellous bone in the vertebral body center, producing the characteristic sandwich vertebra appearance on radiographs.

Alternative names

Sandwich vertebral body, sandwich vertebrae, sandwich spine.

Other associated named signs

Rugger jersey spine is a related but distinct sign seen in renal osteodystrophy/secondary hyperparathyroidism. It also shows dense endplate sclerosis alternating with a lucent center, but the sclerotic bands are typically more ill-defined and less sharply demarcated than the crisp, well-marginated endplate sclerosis of sandwich vertebra in osteopetrosis. The two entities have different underlying diseases (osteopetrosis vs. renal osteodystrophy) despite the similar imaging pattern.

References

1. Spinnato P et al. Spectrum of Skeletal Imaging Features in Osteopetrosis: Inheritance Pattern and Radiological Associations. Genes (Basel). 2022.