Diffuse Idiopathic Skeletal Hyperostosis (DISH) 

Updated: Oct 23, 2018
Author: Bruce M Rothschild, MD; Chief Editor: Jeffrey D Thomson, MD 

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.

Background

Diffuse idiopathic skeletal hyperostosis (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.[4]

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[5, 6, 7, 8, 9, 10, 11] ; DISH was also present in dinosaurs.[12, 13, 14] An age-dependent phenomenon, it occurs in 15-25% of older mammals.

Pathophysiology

Diffuse idiopathic skeletal hyperostosis (DISH) is characterized by a tendency toward ossification of ligament, tendon, and joint capsule (enthesial) insertions.[15] DISH is often a completely asymptomatic phenomenon, with no alterations detectable based on history or through physical examination.

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.[16]

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 tomograph– based prevalence of thoracic DISH was 8.7%.[17] The posterior longitudinal ligament of the cervical spine is ossified in 2% of Japanese individuals but in only 0.16% of white persons.[18] The anterior longitudinal ligament is calcified in 24% of patients with posterior longitudinal ligament ossification.[19]

DISH was reported in 17% of individuals in the Netherlands, paradoxically with male predominance.[20] 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.[21]

Mortality/Morbidity

Diffuse idiopathic skeletal hyperostosis (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. Arthritis, bursitis, 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.[16, 22] One study has showed that DISH may be protective against back pain.[23]

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.[24]

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.[25]

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

The posterior longitudinal ligament of the cervical spine is ossified in 2% of Japanese individuals but in only 0.16% of whites.

Diffuse idiopathic skeletal hyperostosis is present in approximately 19% of men older than 50 years but is found in only 4% of women in this age group.

Diffuse idiopathic skeletal hyperostosis (DISH) 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 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.[24]

 

Presentation

History

Diffuse idiopathic skeletal hyperostosis (DISH) is often an asymptomatic phenomenon that is discovered incidentally on imaging studies taken for some other reason. Reported manifestations, which may result from neuropathy or from physical impingement by bony overgrowth, have included the following1:

  • Polyarticular pain
  • Neck/thoracic/lumbar/extremity pain
  • Acute monoarticular synovitis
  • Limited range of spinal motion
  • Dysphagia
  • Increased susceptibility to unstable spinal fractures
  • Airway obstruction of varying degrees

Physical

If vertebral fusion is quite extensive, reduction in range of spinal motion occurs.[27] Because uniform vertebral involvement is extremely rare, no relatable findings exist.

Causes

Causes are unknown. Diffuse idiopathic skeletal hyperostosis (DISH) is simply a tendency toward calcification of entheses.

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.[28]

 

DDx

Diagnostic Considerations

Other problems to consider in the differential diagnosis are as follows:

  • Spondylosis deformans

  • Fluorosis

  • Osteomalacia

  • Acromegaly

  • Hypervitaminosis A

  • Retinoids

  • Pachydermoperiostosis

  • Hypophosphatemia

  • Hypoparathyroidism

  • Ossified posterior longitudinal ligament (OPLL)

Differential Diagnoses

 

Workup

Laboratory Studies

No laboratory tests are indicated. An apparent association with elevated glucose levels has not been substantiated as a relationship with diabetes.[29, 30]

Imaging Studies

Diffuse idiopathic skeletal hyperostosis (DISH) involves the thoracic vertebrae in 100% of cases, the lumbar vertebrae in 68-90%, and the cervical vertebrae in 65-78%. Ligamentous ossification affects both sides of the lumbar vertebral column but tends to be unilateral in the human spine.

Prominence of DISH on the right lateral aspect of the thoracic spine is apparently related to aortic pulsations. Left-sided overgrowth is much reduced, also probably because of the influence of aortic pulsations, an idea supported by the notation of left-sided prominence in individuals with situs inversus (left-sided thoracic aorta).

The earliest sign of DISH appears to be new bone formation adjacent to the midportion of the vertebral body, a phenomenon often below the limits of radiologic detection. Recognition of DISH is facilitated by its separation from the body of the vertebrae. Radiologically, this appears as a radiodense line paralleling the longitudinal axis of the spine but separated by a clearly definable space.

The most commonly used diagnostic criteria for DISH are those set by Resnick and Niwayama, which are as follows[31, 32] :

  • Calcification and ossification along the ventrolateral aspects of at least four contiguous vertebral bodies, with or without localized pointed excrescences at intervening vertebral body–disk junctions
  • Relative preservation of intervertebral disc height in the involved areas, with absence of extensive radiographic changes of degenerative disc disease (intervertebral osteochondrosis), including vacuum phenomena and vertebral body marginal sclerosis
  • Absence of apophyseal joint bony ankylosis and sacroiliac joint erosion, sclerosis, or intra-articular bony fusion

Criteria suggested by Julkunen and colleagues are substantially the same as those from Resnick and Niwayama, but also include the presence of bridges connecting two vertebral bodies in at least two sites on the thoracic spine.[33] Utsinger criteria are as follows:

  • Definite DISH: Bridging of four contiguous vertebral bodies, primarily in the thoracolumbar spine, minimal intervertebral disk disease, and no facet joint ankylosis
  • Probable DISH: Bridging of two contiguous vertebral bodies plus bilateral patellar tufting, heel spurring, and olecranon tufting.
  • Possible DISH: Two vertebrae joined in the absence of extraspinal enthesophytes, or symmetrical extraspinal enthesophytes in the absence of spinal involvement

The general term DISH emphasizes that the ligamentous ossification phenomenon is not limited to the spine. Exuberant ossification at sites of tendon, ligamentous, or joint capsule insertion (enthesitis) is strongly suggestive of the diagnosis. A tendency toward such ossification at any site of ligament and perhaps tendon insertion appears to exist. One study found pelvic enthesopathy on CT to be significantly more prevalent in patients with DISH compared with matched control patients.[34]

Enthesial reaction at the iliac crest and ischial tuberosities often is referred to as pelvic whiskering and typically is quite exuberant. Such whiskering was noted in two thirds of iliac crests studied and in 53% of ischial tuberosities. Enthesial reaction was noted in 42% of lesser and 36% of greater trochanters of the femur. Enthesial spurs at the site of insertion of the quadriceps mechanism into the patella were present in 29% of patients studied. Osseous bridging of fibula and tibia was noted in 10% of patients. Distal metacarpal and phalangeal capsular hyperostosis were present in 13% of patients with DISH.[16]

Katzman et al reported that DISH is associated with greater kyphosis in older men and women. However, DISH was not significantly associated with a change in kyphosis over 4-5 years, and in women followed over 15 years, those with DISH had less progression of kyphosis than those without DISH.[35]

For complete discussion, see Imaging in Diffuse Idiopathic Skeletal Hyperostosis (DISH).

Histologic Findings

Histologic examination of vertebral specimens from patients with diffuse idiopathic skeletal hyperostosis (DISH) show partial or complete bone bridges consisting of cortical haversian bone, accompanied by morphological changes in the adjoining part of the intervertebral disc.[36] Ossified tissues in DISH are composed of normal-appearing haversian bone, as opposed to the wormian or disorganized structure of bone seen in patients with hypervitaminosis A.[37]

 

Treatment

Approach Considerations

No cure for diffuse idiopathic skeletal hyperostosis (DISH) exists. Therapy is symptomatic and empirical, and may include measures such as the following[2] :

  • Physical therapy
  • Analgesics
  • Sedation
  • Anti-inflammatory drugs
  • Muscle relaxants

Surgery may be indicated to provide relief of severe symptoms, such as airway obstruction or dysphagia, that have not responded to conservative treatment.[2]  Although tracheotomy is the treatment described in most cases of DISH-related airway obstruction in the literature, Yosimatsu et al report a case of successful treatment with careful airway management and surgical osteophytectomy.[38]

 

Follow-up

Complications

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.[39, 40]

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, 41, 42] Note that as well as with fully ankylosed spines, partially ankylosed spines also are at risk, with fractures occurring adjacent to the fused regions.[43] The risk of fracture increases with the number of vertebra ankylosed.[44] Obesity is an additional risk factor for fracture,[45] overstressing the already at-risk spine.

Prognosis

The prognosis is excellent, as diffuse idiopathic skeletal hyperostosis (DISH) is not a source of morbidity or mortality.

 

Questions & Answers

Overview

What is diffuse idiopathic skeletal hyperostosis (DISH)?

When was diffuse idiopathic skeletal hyperostosis (DISH) first identified?

What is the pathophysiology of diffuse idiopathic skeletal hyperostosis (DISH)?

What is the prevalence of diffuse idiopathic skeletal hyperostosis (DISH) in the US?

What is the global prevalence of diffuse idiopathic skeletal hyperostosis (DISH)?

What is the mortality and morbidity associated with diffuse idiopathic skeletal hyperostosis (DISH)?

What are the racial predilections of diffuse idiopathic skeletal hyperostosis (DISH)?

What are the sexual predilections of diffuse idiopathic skeletal hyperostosis (DISH)?

Which age groups are at greatest risk for diffuse idiopathic skeletal hyperostosis (DISH)?

Presentation

What are the signs and symptoms of diffuse idiopathic skeletal hyperostosis (DISH)?

Which physical findings are characteristic of diffuse idiopathic skeletal hyperostosis (DISH)?

What causes diffuse idiopathic skeletal hyperostosis (DISH)?

DDX

Which conditions should be included in the differential diagnoses of diffuse idiopathic skeletal hyperostosis (DISH)?

What are the differential diagnoses for Diffuse Idiopathic Skeletal Hyperostosis (DISH)?

Workup

What is the role of lab testing in the diagnosis of diffuse idiopathic skeletal hyperostosis (DISH)?

What is the role of imaging studies in the diagnosis of diffuse idiopathic skeletal hyperostosis (DISH)?

What are the Resnick and Niwayama diagnostic criteria for diffuse idiopathic skeletal hyperostosis (DISH)?

What are the Utsinger diagnostic criteria for diffuse idiopathic skeletal hyperostosis (DISH)?

Which imaging findings suggest diffuse idiopathic skeletal hyperostosis (DISH)?

Which histologic findings are characteristic of diffuse idiopathic skeletal hyperostosis (DISH)?

Treatment

How is diffuse idiopathic skeletal hyperostosis (DISH) treated?

Follow-up

What are the possible complications of diffuse idiopathic skeletal hyperostosis (DISH)?

What is the prognosis of diffuse idiopathic skeletal hyperostosis (DISH)?