Original Editors Lisa Pernet
Forestier disease or diffuse idiopathic skeletal hyperostosis is a condition characterized by thickening, calcification and ossification of soft tissues, mainly ligaments, joint capsules and insertions of muscles and tendons (entheses). Another aspect of the disease is the formation of large, flowing osteophytes due to abnormal bone growth   .
These ossifications are mostly seen in the axial skeleton, of which the thoracic region is the main location  . Also peripheral entheses may be affected: peripatellar ligaments, Achilles tendon insertion, plantar fascia, shoulders, olecranon and metacarpophalangeal joints   .
Forestier disease or DISH has also been described by various other names, such as spondylosis hyperostotica, spondylitis ossificans ligamentosa, senile ankylosing hyperostosis, physiological vertebral ligamentous calcification and others .
Clinically relevant anatomy
The most common characteristic of DISH is the ossification of the anterior longitudinal ligament of the spine (and various extraspinal ligaments, most commonly in the shoulders, elbows and metacarpophalangeal joints . The anterior longitudinal ligament is most affected at the level of the thoracic spine .
Forestier disease (DISH) is most common in the elderly population (>50 years old) and the prevalence increases with age . According to US prevalence estimates, man are more frequently affected (25%) than women (15%) in a population age 50 and older.
Although the etiology of the disease is not fully understood, studies have already shown that the clinical features are related to the formation of new bone. It is assumed that several metabolic factors affect the onset of the disease    .
- waist circumference
- BMI / Obesity
- diabetes mellitus
- coronary artery disease
DISH is often asymptomatic  , this is why the diagnosis is usually made on the basis of the radiographic images. When the disease becomes symptomatic, the main clinical features are pain (not always), stiffness and decreased mobility (ROM)  . Side-bending is the motion that is affected the most with the right side of the thoracic spine more often affected than the left side, the exact cause of it is not found.
- dysphagia (caused by compression of osteophytes): Dysphagia is often related to DISH. It can occur because of mechanical obstruction or impingment of the osteophytes at the larynx or pharynx .
- oesophagal obstruction
- cervical myelopathy
- atlantoaxial subluxation
- spinal stenosis
- ossification of the posterior longitudinal ligament
- spinal cord injury
- foreign body sensation
- neurologic manifestations duo to compression of the spinal cord
- hypercholesterinemia (resulting in cardiovacular comorbidities)
- peripheral joint affection
Dish often coexists with osteoarthritis   . Although they both occur in the same age group, there are clear differences between the two conditions on which we can make a distinction: - gender: women (OA) – men (DISH)
- affected structure: cartilage (OA) – entheses (DISH)
- different peripheral sites 
Both diseases affect the axial skeleton and peripheral entheses . In both disorders similar postural abnormalities can be found as a result of the decrease in spinal mobility. Differential diagnosis is based on radiological features and clinical signs. An important difference is the age at which the diseases start. Ankylosing spondylitis starts at an earlier age than DISH.
When we compare the symptoms we see some differences:
The symptoms of AS consist of inflammatory back pain and buttock pain, reduced spinal movement, and progressive typical postural abnormalities known as “Bechterew stoop.”
DISH is more considered as a disease with an asymptomatic course or with mild dorsolumbar pain and/or some restriction of spinal motion.
DISH patients have a higher chance to report a past history of upper extremity pain, medial epicondylitis of the elbow, enthesitis of the patella or heel, or dysphagia than spondylosis patients .
Because of the absence of validated diagnostic criteria, different sets of classifications criteria are commonly used . The diagnosis of DISH is based on radiological findings, defined by Resnick and Niwayana. This allows a differentiation of the entity towards ankylosing spondylitis . According to this definition, the presence of flowing calcifications and ossifications mainly along the anterolateral aspect (anterior longitudinal ligament) of at least 4 contiguous vertebrae (across 3 intervertebral disc spaces) with preserved disc height is indicative of the condition    . According to Resnick and Niwayana, absence of apophyseal joints or sacroiliac inflammatory changes is the last criteria .Sometimes the ossification of the anterior longitudinal ligament can be associated with the ossification of the posterior longitudinal ligament or the calcification of the ligamentum flavum. It occurs often in different spinal regions.
When a patient meets these criteria, one can use the classification system established by Mata (1998). With this scoring system the amount of ossification of each vertebral level and the degree of bridging of the disc space can be assessed .
Mata scoring system:
- 0: no ossification
- 1: ossification without bridging
- 2: ossification with incomplete bridging
- 3: ossification with complete bridging
Whereas conventional radiography can only be used for the diagnosis of DISH, CT and MRI can be used to detect complications associated with the disease .
Measurements of spinal mobility : -
- Schober's test
- finger-to-floor distance
- lumbar lateral flexion
- chest expansion
- occiput-to-wall distance
- flexion and extension of the cervical spine
Radiography of the thoracic and lumbar spine is the single most useful imaging modality in the diagnosis of DISH. Computed tomography (CT) scanning can be used to evaluate complications, such as fracture, or symptoms that can be caused by pressure effects on the trachea, esophagus, and veins. Bone scanning and magnetic resonance imaging (MRI) are also used but they do not play a significant role in the diagnosis of DISH .
The management of DISH consist primarily of a conservative approach such as symptomatic therapy  , if this is not effective, surgery is often the only remaining option . Surgery is rarely used, except in cases where nerve roots or the spine are compressed because of the extra bone growth. Symptoms of difficulty with swallowing can be decreased by taking out the spurs trough surgery.Only few therapeutic interventions have been described for DISH, because this disease is often seen as a part of osteoarthritis. Currently, people often assume that most treatments for OA can also be useful for the treatment of DISH .
Main treatment goals : - reduce pain and stiffness
- prevent, retard or arrest progression
- treatment of associated metabolic disorders
- prevent complications
Several therapeutic modalities can be used to reduce pain, including both medical and physical therapy treatments. The medical aspect, mainly includes the use of NSAIDs (nonsteroidal anti-inflammatory drugs) and mild analgesics and occasionally, in severely symptomatic cases, local corticosteroid injections   . Local heat can be used to reduce pain temporary  .
To treat the painful disorders of the spine (or extremity) joints, several therapeutic modalities can be used. The medical treatment includes the use of NSAIDs (nonsteroidal anti-inflammatory drugs) and mils analgesics and occasionally, in severely symptomatic cases, local corticosteroid injections  Several studies also recommend local heat to reduce the pain temporary of the affected joint sections. The complaints can also be postively influenced by wearing appropriate bandages or by local injection treatment with anesthetic and cortisone additive..
Since it is believed that DISH is related to several metabolic diseases (eg, diabetes mellitus, obesity, hyperuricemia, hypertension, coronary heart disease…) and risk factors, one will also have to intervene on these disorders. Many of these factors are in turn related to obesity, so as a physiotherapist one must encourage patients to adopt a healthier, active lifestyle and thus promote weight loss. Moreover, light aerobic activity leads to reduced pain and stiffness .
Physical Therapy Management
If DISH is symptomatic, there are often complaints of stiffness that can lead to limitations of movement of the spine. In this case, it is useful to add stretching and mobility exercises to the rehabilitation program to maintain or regain range of motion . Regular exercises such as walking can also be recommended for the stifness and pain. Currently there is a lack of specific therapeutic interventions but correction of the associated metabolic derangements seems to have a positive effect and is therefore recommended .Many of the metabolic and cardiovascular complications of factors can be related to obesity. The physiotherapist must encourage the patients to adopt a healthier, active lifestyle and thus promote weight loss. Aerobic activity also leads to reduced pain and stifness..
If surgery has been done physical therapy will help you to return to your normal activities. The therapy after surgery is similar to the conservative treatment and includes stretching, increasing range of motion, walking. Repeat examination and imaging studies will be done to evaluate the progression.
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