Diffuse idiopathic skeletal hyperostosis

Last revised by David Bassett on 31 May 2024

Diffuse idiopathic skeletal hyperostosis (DISH), also known as Forestier disease, is a common condition characterized by bony proliferation at sites of tendinous and ligamentous insertion of the spine affecting elderly individuals. On imaging, it is typically characterized by the flowing ossification of the anterior longitudinal ligament involving the thoracic spine and enthesopathy (e.g. at the iliac crest, ischial tuberosities, and greater trochanters). There is no involvement of the sacroiliac synovial joints. DISH is defined as flowing bridging anterior osteophytes spanning at least four vertebral levels, with normal disc spaces and sacroiliac joints

DISH most commonly affects the elderly, especially 6th to 7th decades 3. The estimated frequency in the elderly is ~10% 6, with a male predominance. 

Recognized associations include:

The condition is commonly identified as an incidental finding when imaging for other reasons. However, spine stiffness and decreased mobility are referred to as possible symptoms. 

The etiology of DISH is still unknown. Histopathological features of spinal DISH include 5:

  • focal and diffuse calcification and ossification of the anterior longitudinal ligament

  • paraspinal connective tissue and annulus fibrosus

  • degeneration of the peripheral annulus fibrosus fibers

  • anterolateral extensions of fibrous tissue

  • hypervascularity

  • chronic inflammatory cellular infiltration

  • periosteal new bone formation on the anterior surface of the vertebral bodies

The cervical and thoracic (particularly T7-11 5) spines, in particular, are affected. Additionally, enthesopathy may be identified in the pelvis and extremities.

  • flowing ossifications: florid, flowing ossification along the anterior or right 7 aspects of at least four contiguous vertebrae. The left lateral aspect is usually spared in the thoracolumbar spine, thought due to aortic pulsation inhibiting ossification 5. For the same reason, the right lateral aspect is spared in situs inversus 5.

  • disc spaces are usually well preserved

  • ankylosis is more common in the thoracic than cervical or lumbar spine

    • frequently incomplete

    • can have interdigitating areas of protruding disc material in the flowing ossifications

  • no sacroiliitis or facet joint ankylosis although sacroiliac joint anterior bridging, posterior bridging, entheseal bridging may be present 10

  • enthesopathy of the iliac crest, ischial tuberosities, and greater trochanters

  • spur formation in the appendicular skeleton (olecranon, calcaneum, patellar ligament) frequently present

  • 'whiskering' enthesophytes

DISH is generally managed clinically with analgesics and non-steroidal anti-inflammatory drugs when pain and stiffness are related. Possible complications may require specific treatment: 

  • acute spinal fractures in low impact trauma

    • inspect the ossified ligaments for disruption, and compare with prior imaging where available to discern fracture from a region without ossification

    • note that fractures can also occur above or below the rigid segment due to altered biomechanics

    • chalk stick fracture

  • dysphagia is reported in ~28% of cases involving the cervical spine 12, which may be caused by mechanical compression due to anterior cervical bone production 8

  • cervical DISH can make intubation more difficult 11

  • lumbar DISH can cause radiculopathy 11

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