Forestier's disease

Forestier's Disease: What You Need to Know About This Bone and Ligament Disorder

Forestier’s disease causes excessive bone formation along certain ligaments, especially in the spine. Ligaments are strong bands that connect bones. The English name for the disease is diffuse idiopathic skeletal hyperostosis, often abbreviated as DISH. This bone formation, called ossification, primarily affects the ligaments in front of the vertebrae—the stacked bones that form the spine. It develops gradually, especially in the middle of the back.^{1, 2} The condition may seem alarming, but it does not always cause symptoms. When pain or stiffness occurs, treatment can help manage it and maintain mobility.

What exactly is Forestier's disease?

Forestier's disease causes bone to form on the ligaments in front of the vertebrae, especially in the thoracic region—that is, the middle of the back. These bony deposits can gradually spread and, in some cases, fuse several vertebrae together.³ On an X-ray, this bone may appear as a continuous band in front of several vertebrae. It follows the anterior longitudinal ligament, which runs along the front of the spine.⁴ This appearance is sometimes compared to a stream of candle wax, as noted in a 2023 imaging study. This comparison also applies to melorheostosis, another bone disorder. Therefore, it is not sufficient on its own to distinguish between these conditions.⁵

Forestier’s disease differs from ankylosing spondylitis, a condition in which inflammation—a defensive reaction of the body—plays a central role. Forestier’s disease is usually classified as non-inflammatory and can affect several regions of the skeleton. Researchers are, however, investigating the possible role of low-grade local inflammation. It is also associated with abnormalities in the way the body uses sugars and fats.⁶

What are the risk factors for developing Forestier's disease?

Forestier's disease is more common in men, older adults, and people with obesity or diabetes. It is also associated with abnormal blood lipid levels, known as dyslipidemia, and high uric acid levels, known as hyperuricemia.^{7, 8} These associations do not prove that each of these factors causes the disease. The observed links to weight and cholesterol do not yet explain how bone is formed.

These health problems can occur in the same person. A common cause remains a hypothesis. Uric acid is a waste product naturally present in the blood. High levels can contribute to gout, a condition in which crystals cause painful joint attacks. High uric acid levels have been reported more frequently in Forestier.⁸ This does not prove that gout causes this disease.

The prevalence of the disease increases with age. This observation does not allow us to precisely distinguish the role of aging from that of other associated factors.

What are the symptoms of Forestier's disease?

Symptoms of Forestier's disease, when present, may include pain, stiffness of the spine, and reduced trunk mobility.¹ The presence of an extra bone does not automatically mean that it is painful. Many people can live with this condition without ever experiencing pain or discomfort. This ossification may be discovered by chance on images taken for another reason.^{1, 9}

Pain can affect the middle back, lower back, or neck. Its intensity varies; it may remain mild even when several vertebrae are fused together. A review of the disease’s symptoms describes this situation in particular. Stiffness can limit trunk movement and be more pronounced in the morning, as explained in the Cleveland Clinic fact sheet.

The condition can also affect the points where tendons attach to bone. Tendons connect muscles to bones. A study comparing people with and without Forestier’s syndrome found that those with the condition more often experience involvement of the heel or kneecap.¹⁰The 2023 imaging review also describes bone formation at the attachment site of the Achilles tendons, behind the heel. Pain may sometimes affect the neck rather than the middle of the back. When the cervical spine is affected, ossifications may also be associated with difficulty swallowing.¹ These various symptoms may occur separately.

What are the serious symptoms to watch out for?

Forestier’s warning signs include new or worsening weakness in the legs, loss of sensation or balance, and new bladder or bowel problems. These signs may indicate nerve damage and require urgent evaluation. Pain following a fall or impact—even a minor one—also requires urgent medical attention due to the risk of a fracture.

Severe weakness or paralysis in one or both legs constitutes a medical emergency. Similarly, a significant or even complete loss of sensation in one or both legs must be evaluated immediately. A recent loss of balance while walking or a significant, new difficulty coordinating movements are also concerning signs that require prompt medical attention.

Any new difficulty starting to urinate, emptying the bladder, or controlling urine or bowel movements requires an immediate visit to the emergency room. A new loss of sensation around the genitals, between the legs, or when wiping requires the same attention, even without the other signs. These symptoms may indicate cauda equina syndrome, a compression of the nerves at the base of the spine. The NHS fact sheet on these symptoms recommends going to the emergency room immediately if any of these signs appear suddenly.

These complications are rare among all cases of lower back pain. However, a spine that has been stiffened by the Forestier procedure can fracture after even a minor impact. After a fall or an accident, have any new back or neck pain evaluated immediately—do not wait for paralysis to set in. A standard X-ray may fail to detect certain fractures; your doctor will determine the appropriate tests. The Forestier imaging review explains this risk. New difficulty swallowing also requires medical attention. If you have trouble breathing, call emergency services.

What are the causes of Forestier's disease?

The exact cause of Forestier's disease remains unknown, although several hypotheses have been put forward by scientific researchers.⁷ Familial forms and genetic variations have been described. Genes carry the instructions that guide the body’s functioning.^{11, 12} The family study involved 12 families from the Azores who also had calcium deposits in the cartilage, the lining of the joints. This finding does not necessarily describe all forms of Forestier’s disease. Researchers are studying how genes might influence bone formation.

The condition is often associated with obesity, diabetes, and certain difficulties the body has in managing blood sugar. Glucose intolerance means that blood sugar levels rise more than expected. Hyperinsulinemia refers to high levels of insulin, the hormone that helps regulate blood sugar.¹³ Researchers are therefore investigating the possible role of sugars, fats, and uric acid in bone formation. The observed associations do not prove that any of these factors triggers the disease.⁷

IGF-1 is a protein involved in tissue growth. Its role in bone formation is being studied. One study found higher levels of IGF-1 in people with Forestier’s disease who have symptoms.¹⁴ However, another study found normal levels of IGF-1, despite a higher prevalence of abnormal levels of other hormones—the substances that transmit messages throughout the body.¹⁵ The results vary depending on the study groups. They are not sufficient to prove that IGF-1 causes bone formation in Forestier syndrome. The links to diabetes and obesity also remain to be clarified.

How is Forestier's disease diagnosed?

The diagnosis of Forestier’s disease is based on spinal imaging, interpreted in conjunction with your symptoms and a physical examination. In particular, the doctor looks for bony bridges spanning several vertebrae.^{16, 6} The classic diagnostic criteria involve the presence of bony growth connecting at least four consecutive vertebrae, with relatively preserved disc height. The discs are cushions between the vertebrae. The doctor also examines the joints of the spine and pelvis to rule out other conditions. These criteria primarily identify disease that is already advanced. Other criteria have been proposed for early-stage forms, but they are less widely adopted. The history of symptoms—that is, how the pain began and has progressed—provides important clues.The physical examination assesses spinal mobility, painful areas, muscle strength, and sensation. These tests specifically look for nerve damage.

Medical imaging tests confirm the bone changes characteristic of Forestier's disease. Standard X-rays typically reveal the characteristic ossification of the anterior vertebral ligaments.¹⁷ In some cases, blood tests may be performed to rule out other inflammatory conditions and to measure, in particular, blood sugar and certain blood lipids.

Among workers with recent lower back pain that prevented them from working, an early MRI performed without a recognized medical indication was associated with longer periods of disability and higher costs. MRI, or magnetic resonance imaging, uses a magnetic field to produce detailed images.¹⁸ This study on back pain does not prove that MRI causes a poor outcome. It involved individuals without a recognized indication for this test. It does not call into question imaging that is necessary to identify a herniated disc or to look for a fracture or nerve compression.

Images of the spine often show age-related changes—particularly in the discs—in people who are not experiencing pain. These changes are a normal part of aging and are not necessarily the cause of the pain.¹⁹

When to consult a physiotherapist for Forestier's disease?

A physical therapy consultation is recommended when back pain or stiffness limits your activities, provided there are no urgent signs as described above. Physical therapy for lower back pain typically includes mobility, stretching, and strengthening exercises. In a small trial conducted by Forestier, 15 of the 17 participants completed a 24-week program. Eight of these 15 people reported feeling better. The most noticeable improvement was in a measure of forward movement of the lower back. The other physical changes were minor and inconclusive.²⁰ This trial, which lacked a control group, yielded encouraging results, though it did not allow for distinguishing the effect of the exercises from natural progression or other influences.

In Quebec, you can see a physical therapist without a doctor’s prescription. However, this option does not replace seeking urgent medical attention if you experience the symptoms described above. Physical therapists are primary-care professionals who can assess your condition and refer you to other health care professionals if necessary. If your condition requires you to see a doctor, your physical therapist will be able to tell you so and refer you to the appropriate care.

What are the physiotherapy treatments for Forestier's disease?

Physical therapy at Forestier offers tailored exercises, advice on adjusting your activities, and—depending on the evaluation—manual therapy to improve comfort. The physical therapist first assesses which movements are difficult and which activities are limited. He or she examines the mobility of your spine and looks for signs of nerve damage, particularly through tests of strength, sensation, and movement response.

Your posture and movements will be observed to identify the positions and actions that are currently triggering your pain. An uncomfortable position can be adjusted based on your tolerance and the limitations caused by stiffness in your spine. The goal is to make your daily activities easier. Your strength and endurance will also be assessed.

Not all joint mobilizations and manipulations are suitable for a spine stiffened by Forestier’s syndrome. Mobilizations are movements applied by the therapist; manipulations involve a rapid thrust. A neck fracture has been reported following a manual maneuver in a person with Forestier’s syndrome. The exact maneuver could not be determined in that case report. Inform your physical therapist of the diagnosis and any recent falls. Areas connected by bone should not be forced. The evaluation guides the selection of gentle care for comfort and appropriate movements, including for neurological symptoms when such movements are appropriate.

You may be given specific exercises to do at home to maintain or improve your range of motion. The small study on Forestier examined daily mobility, stretching, and strengthening exercises, with 14 supervised sessions during the first eight weeks.²⁰ These exercises target symptoms and functional abilities. No available treatment can cure the disease itself.¹² Depending on the results of your evaluation, the program may include exercises for the stabilizing muscles, which focus on control and endurance of the muscles surrounding your spine. The choice depends on your abilities, symptoms, and goals. Your physical therapist will also teach you how to adjust the duration, intensity, and breaks in your daily activities and leisure pursuits, and will provide personalized advice on your posture and movement habits.

Treatment aims to reduce pain and stiffness and make it easier to perform daily activities. It does not eliminate bone bridges. In the small exercise trial, eight out of 15 participants reported an improvement after 24 weeks; three saw no change, and four were unsure.²⁰ The physical therapist will therefore monitor your actual response and adjust the program in consultation with you.

What to do at home for Forestier's disease?

Home care for Forestier includes walking and appropriate mobility exercises, provided the assessment indicates that these activities are appropriate for your condition. A recent fall or any urgent symptoms require medical attention first. Next, avoid long periods of inactivity if they increase your stiffness. For recent lower back pain, staying active offers slight benefits over bed rest. For sciatica—pain that radiates down the leg and is related to a nerve in the lower back—this review finds little or no difference between these two approaches.²¹

If you are not very active and your condition allows it, start with short, regular walks. Do the recommended back mobility exercises as much as you can tolerate, without straining stiff areas. If you are already active, continue with activities that do not cause too much pain. Strength and endurance exercises can be part of your program to maintain your strength and mobility.

For persistent lower back pain with no specific identified cause, exercise provides modest benefits in terms of pain relief and functional ability compared to standard care. The review does not identify any one type of exercise as clearly superior to others. These findings pertain to persistent lower back pain; their application to Forestier requires adaptation. Work with your physical therapist to choose activities that you can tolerate.²²

A professional evaluation helps you understand what is limiting your activities and adjust your treatment plan.

What conditions are associated with Forestier's disease?

Forestier’s disease has been associated with lumbar osteoarthritis and lumbar stenosis in some studies. Lumbar osteoarthritis refers to changes in the joints of the lower back; stenosis is a narrowing of the space through which the nerves pass. A population-based study found an association with lumbar osteoarthritis, referred to as spondylosis in that study.²³ The presence of both conditions in the same person does not prove that one causes the other. See our guide onlumbar osteoarthritis to learn more.

Lumbar spinal stenosis is associated with Forestier's disease.²⁴ The authors suggest that the parts of the spine connected by bone place a greater load on the parts that remain mobile. This explanation remains a hypothesis. The formation of bone in front of the vertebrae does not, in and of itself, mean that the neural canal is narrowed. Stenosis can cause pain, numbness, or weakness in the legs.

Lumbar facet syndrome involves the joints at the back of the vertebrae and may contribute to pain in people with Forestier's disease. Pain originating from these joints may coexist with Forestier's disease, but it must be evaluated separately. The mere presence of calcium deposits does not confirm this as the source of the pain.

Can Forestier's disease be prevented?

There is currently no proven method for preventing Forestier’s disease. Regular exercise, managing your diabetes and cholesterol, and discussing your weight with a healthcare professional are still beneficial for your health. Obesity is associated with Forestier’s disease, but this does not prove that weight loss prevents its development.

A balanced diet and regular physical activity also support muscle and joint health. Their effect on bone growth in Forestier has yet to be determined.

How can I get help for Forestier's disease?

A consultation with our physical therapists will help you understand Forestier’s disease and choose a treatment plan tailored to your specific challenges. The evaluation focuses on your movements, activities, and goals. The urgent symptoms described above require immediate medical attention.

Schedule an appointment to have your symptoms evaluated and discuss a treatment plan.

Sources

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