Diffuse Idiopathic Skeletal Hyperostosis (DISH)

Updated: Feb 27, 2024
  • Author: Bruce M Rothschild, MD; Chief Editor: Jeffrey D Thomson, MD  more...
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Overview

Practice Essentials

Diffuse idiopathic skeletal hyperostosis (DISH), also known as Forestier disease, describes a phenomenon characterized by a tendency toward ossification of ligaments. It most characteristically affects the spine. [1, 2] (See the image below.) Ossification of the longitudinal ligaments (especially the anterior ligaments) of the spine produces a tortuous paravertebral mass anterior to and distinct (at least radiologically) from the vertebral bodies. [3] Grossly, the appearance is that of candle wax dripping down the spine.

Radiograph of the thoracic spine (anteroposterior Radiograph of the thoracic spine (anteroposterior view) showing osteophytes on the right side only, a feature typical of diffuse idiopathic skeletal hyperostosis.

While the thoracic anterior longitudinal ligament is ossified, the areas of ossification often meet without fusion. Motion actually is possible, in contrast to lumbar vertebral bridging, which is associated with loss of lumbar motion. The zygapophyseal and sacroiliac joints are not involved in DISH, and the intervening intervertebral disk space is preserved.

DISH appears to be a phenomenon, largely age related, rather than a disease. It is often asymptomatic, discovered incidentally on imaging studies taken for some other reason. Clinical manifestations, such as back pain and stiffness, [4] may result from neuropathy or from physical impingement by bony overgrowth (see Presentation).

No cure for DISH exists. Therapy is symptomatic and empirical. Surgery may be indicated to provide relief of severe symptoms, such as airway obstruction or dysphagia. (See Treatment.)

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Background

DISH was first described in 1948 by Forestier and Rotes-Querol in a report on nine patients, ranging in age from 50 to 73 years, who suffered from spinal rigidity and had exuberant osteophytes on radiologic studies. These authors termed the condition senile vertebral ankylosing hyperostosis. [5]

DISH is well represented in the zoologic and paleontologic record. It is found in 1-3% of baboons and monkeys, as well as in gorillas, bears, camels, horses, bison, musk oxen, canids, felids, and whales. [6, 7, 8, 9, 10, 11, 12]  DISH was also present in dinosaurs. [13, 14, 15] An age-dependent phenomenon, it occurs in 15-25% of older mammals.

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Pathophysiology

DISH is characterized by a tendency toward ossification of ligament, tendon, and joint capsule (enthesial) insertions. [16] DISH is often a completely asymptomatic phenomenon, with no alterations detectable based on history or through physical examination.

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Etiology

Causes are unknown. DISH is simply a tendency toward calcification of entheses.

Epidemiologic studies have identified a range of risk factors for DISH, with higher rates seen with age over 50 years, in men compared with women, and in the White population compared with Black, Asian, and Native American populations. [4]  Additional risk factors include the following [17] :

  • Obesity
  • Hypertension
  • Metabolic syndrome
  • Type 2 diabetes mellitus
  • Hyperuricemia

Lantsman et al reported that abdominal computed tomography showed significantly more visceral adipose tissue, as well as a significantly higher ratio of visceral to subcutaneous adipose tissue, in 43 patients with DISH as compared with 42 controls. These authors note that visceral adipose tissue is by itself associated with bone proliferation, and suggest that it is potentially a pathogenic pathway for enthesopathic excessive bone production in DISH. [18]

However, research has yet to establish a causal connetion between those risk factors and DISH. [19] One of the sources of confusion may be the choice of comparison populations: Even if DISH is accurately diagnosed, with complete exclusion of spondyloarthropathy cases, it is unclear whether DISH has actually been excluded in the patients used for controls.

 

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Epidemiology

Frequency

United States

Diffuse idiopathic skeletal hyperostosis (DISH) is present in approximately 19% of men and 4% of women older than 50 years. Frequency information in the US was derived from the study of nonselected skeletal/cemetery populations. [20]

International

In a study by Mori et al of 3013 Japanese patients (1261 females and 1752 males) with a mean age of 65 years, the computed tomography–based prevalence of thoracic DISH was 8.7%. [21] The posterior longitudinal ligament of the cervical spine is ossified in 2% of Japanese individuals but in only 0.16% of White persons. [22] The anterior longitudinal ligament is calcified in 24% of patients with posterior longitudinal ligament ossification. [23]

In a study from the Netherlands of 501 outpatients older than 50 years who underwent chest x-rays for non–spine-related conditions, the prevalence of DISH was 17%, with male predominance. [24] A South African study of hospitalized patients 40 years of age and older found that the prevalence of DISH in African Blacks was 3.8% in men and 4.2% in women; the prevalence rose with increasing age, from 1% in the 40-49 year age group to 13.6% in those over 70 years. [25]

Race-, sex,-, and age-related demographics

DISH is present in approximately 19% of men older than 50 years but is found in only 4% of women in this age group. It is uncommon in patients younger than 50 years and is extremely rare in patients younger than 40 years.

A study from Finland [26] revealed the age frequency in Finnish men to be as follows:

  • 40-49 years - 0.3%
  • 50-59 years - 2.7%
  • 60-69 years - 8.4%
  • 70 years or older - 11.2%

The same study revealed the age frequency in Finnish women to be as follows:

  • 40-49 years - 0.2%
  • 50-59 years - 1.7%
  • 60-69 years - 4.3%
  • 70 years or older - 6.9%

In a US study of community-dwelling men (n = 630) and women (n = 961), mean age 71.5 years, from the Rancho Bernardo Study, DISH was present in 25.6% of men and 5.5% of women. [27]

A study of middle-aged and elderly people randomly sampled from the resident registry of a rural town in Japan identified DISH in 72 (17.5%) of the 413 participants. The prevalence of DISH tended to increase with age, from 3.1% in subjects in their 50s to 14.0% in those in their 60s, 24.3% in those in their 70s, and 29.0% in those in their 80s. In addition to aging, other independent factors associated with DISH were hypertension (odds ratio [OR] 1.93), male sex (OR 2.88) and elevated body mass index (OR 19.1). [28]

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Prognosis

Patients with diffuse idiopathic skeletal hyperostosis (DISH) have an excellent prognosis, as the condition is rarely life-threatening and causes limited morbidity.

DISH appears to be a phenomenon rather than a disease. A double-blind controlled evaluation (in which controls and patients were drawn from the same population) revealed no associated pathology. Arthritisbursitis, and tendinitis appeared no more frequently in patients with DISH than in controls. Any back pain present was no different in character or duration than that noted in control subjects. A history of back injury was actually found to be twice as frequent in control subjects as it was in patients with DISH. Back flexibility was no more limited in patients with DISH than it was in controls. In fact, patients with DISH who had decreased lumbar spinal motion had a lower frequency of back pain, implying that DISH may be protective. [20, 29]  One study has shown that DISH may be protective against back pain. [30]

In another study, people with DISH were more likely to experience physical functional impairment. This included 1.72-fold increased odds of self-reported difficulty bending; worse grip strength; and in men only,  2.17-fold increased odds of being unable to complete 5 chair stands without using their arms. [27]

A study of 1063 patients treated surgically for lumbar spinal stenosis found that reoperations were performed significantly more often in patients with DISH that extended to the lumbar segment: 22% of such patients underwent reoperation, compared with 7.3% of patients without lumbar DISH (P < 0.001). The authors suggest that the unfavorable outcomes in patients with lumbar DISH may be due to the decreased number of lumbar mobile segments. [31]

Overgrowth of ligamentous calcification could impinge on other structures (eg, the esophagus). Reports of this are rare and often represent inadvertently discovered, neurologically mediated swallowing deficits. [32, 33]   Compression of the larynx leading to vocal cord paresis and airway obstruction has been reported. [34]

Posterior longitudinal ligament ossifications may impinge on the spinal cord on rare occasions.

Reduced vertebral column flexibility predisposes to vertebral fracture. Vertebral fracture risk (cervical, 60%; thoracic, 34.5%; lumbar, 5.5%) is inherent with an ankylosed hyperostotic vertebral column from minor trauma, preoperative and postoperative positioning, or intraoperative maneuvers (eg, retroperitoneal or hip replacement surgery). [3, 35, 36]  Note that as well as with fully ankylosed spines, partially ankylosed spines also are at risk, with fractures occurring adjacent to the fused regions. [37]  The risk of fracture increases with the number of vertebra ankylosed. [38]  Obesity is an additional risk factor for fracture, [39]  overstressing the already at-risk spine.

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