SUMMARY Diffuse idiopathic skeletal hyperostosis (DISH), also known as Forestier disease, is a common disorder of unknown etiology characterized by enthesopathy of the spine and extremities. It usually presents with back pain and spinal stiffness Diagnosis can be confirmed with radiographs of the spine. A CT scan should be performed whenever there is concern for a fracture following low-energy trauma Treatment is usually activity modification, physical therapy, and bisphosphonate therapy. Associated spinal fractures are treated with long-segment spinal fusion Epidemiology Demographics overall incidence is 6-12% uncommon in patients <50 y/o prevalence >50 y/o (25% males, 15% females) >80 y/o (28% males, 26% females) less common in Black, Native-American, and Asian populations Location occurs anywhere in the spine most common in the thoracic spine (right side) > cervical spine > lumbar spine login to view 1 more bullet symmetric in the cervical and lumbar spine (syndesmophytes on both the left and right sides of the spine) Risk factors gout hyperlipidemia diabetes ETIOLOGY Associated conditions lumbar spine lumbar spinal stenosis cervical spine dysphagia and stridor hoarseness sleep apnea difficulty with intubation cervical myelopathy spine fracture and instability ankylosis of the vertebral segments proximal and distal to the fracture creates long lever arms that may cause displacement, even after low-energy injuries hyperextension injuries are common seemingly minor, low-energy injury mechanisms may result in unstable fracture patterns login to view 1 more bullet Presentation Symptoms often asymptomatic and discovered incidentally thoracic and lumbar involvement mild chronic back pain login to view 1 more bullet stiffness login to view 2 more bullets cervical involvement (with large anterior osteophytes) pain and stiffness dysphagia stridor hoarseness sleep apnea Physical exam decreased ROM of the spine neurologic symptoms of myelopathy or spinal stenosis Imaging Radiographs recommended views AP and lateral of the involved spinal region findings non-marginal syndesmophytes at 3 successive levels (4 contiguous vertebrae) thoracic spine login to view 4 more bullets cervical spine login to view 3 more bullets lumbar spine login to view 1 more bullet involvement of other joints (e.g. the elbow) Technetium bone scan increased uptake in areas of involvement may mimic metastatic disease CT or MRI patients with DISH, neck pain, and a history of trauma must be evaluated for occult fracture with CT Differential DISH vs. Ankylosing Spondylitis DISH <i>Ankylosing Spondylitis</i> Syndesmophytes Nonmarginal Marginal Radiographs "Flowing candle wax" "Bamboo spine" Squaring of vertebral bodies "Shiny corners" at the attachment of the annulus fibrosus (Romanus lesions) Disc space Preservation of the disc space AS in the cervical spine may show ossification of the disc space Osteopenia No osteopenia (rather, there may be increased radiodensity) Osteopenia present HLA No evidence of an association with HLA-B27 Associated with HLA-B8 (common in patients who have both DISH and diabetes) Strong association with HLA-B27 Age group Older patients (middle-aged) Younger patients SI joint involvement No involvement (SI joint abnormality generally excludes a diagnosis of DISH) Bilateral sacroiliitis Diabetes Yes No Diagnosis Diagnostic criteria flowing ossification along the anterolateral aspect of at least 4 contiguous vertebrae preservation of disc height in the involved vertebral segment and a relative absence of significant degenerative changes (e.g. marginal sclerosis of the vertebral bodies or vacuum phenomenon) absence of facet-joint ankylosis and absence of SI joint erosion, sclerosis, or intra-articular osseous fusion Treatment Nonoperative activity modification, physical therapy, brace wear, NSAIDs, and bisphosphonate therapy indications login to view 1 more bullet cervical traction indications login to view 2 more bullets Operative spinal decompression and stabilization indications login to view 1 more bullet Complications Mortality for cervical spine trauma in DISH 15% for those treated operatively 67% for those treated nonoperatively higher mortality rates than patients with cervical spine trauma and ankylosing spondylitis similar mortality rates to patients with ankylosing spondylitis Heterotopic ossification increased risk of HO after THA 30-50% for THA in patients with DISH <20% for THA in patients without DISH