Heterotopic Ossification spinal cord injury x-ray

Heterotopic Ossification and Spinal Cord Injuries

There are several secondary complications and conditions associated with spinal cord injuries. They include issues such as impaired bladder function and autonomic dysreflexia, a potentially dangerous condition involving a sudden onset of high blood pressure.

These secondary complications often require careful management by the individual and those providing care. One perhaps lesser-known complication is Heterotopic Ossification (HO),which affects the area below a spinal cord injury.

Here we take a closer look at HO, what the symptoms are and how it is treated when it affects spinal cord injury patients. 

What is Heterotopic Ossification?

Heterotopic Ossification is an abnormal bone growth that appears in the soft tissue surrounding certain joints in the body. This condition is likely to affect around 1 in 5 people who have a spinal cord injury (SCI) and it can be a painful experience.

The bone growth as a result of HO occurs more rapidly than would normally occur. It may involve the development of jagged protrusions which can have a fairly quick impact on the individual’s mobility as well as causing them pain.

Heterotopic Ossification doesn’t just occur following an SCI. We see HO in cases where someone has had a stroke, patients with multiple sclerosis, and where an individual has had a total hip replacement.

The vast majority of cases (90%) of HO in SCI patients occur in the hip, but it can also be seen in areas like the knees. The growth generally forms below the level in which the spinal cord injury was sustained.

Symptoms of Heterotopic Ossification

X-ray image hip Heterotopic Ossification

Heterotopic Ossification can begin to appear in the days following an SCI but it also may occur many weeks or months later. In certain individuals, the issue becomes apparent for the first time several years after they sustained their spinal cord injury.

HO tends to affect younger patients. If you are over the age of 40, you are less likely to develop Heterotopic Ossification.

The symptoms of this HO include:

1. Loss of Range of Movement

If the individual has a complete SCI, they may not notice they have HO. For incomplete SCIs there is a loss of range of movement in the area where the condition has occurred. In the hips, this could mean an individual has difficulty bending. They might find it painful to bend their knee or move their ankle.

2. Swelling, Pain and Autonomic Dysreflexia

HO happens fairly rapidly and there is usually a physical sign such as redness and swelling that indicates a problem. In more severe examples, swelling can affect the whole leg and be extremely painful. This condition may also be accompanied by a fever.

Because the bone grows quickly and this growth is jagged, it is often uncomfortable and painful.

For patients who have no sensation below the point of their injury and can’t feel the pain, this can cause an additional problem; autonomic dysreflexia (AD).

AD is a response to an emergency in the body such as excessive pain or injury. Normally we will do something to get away from this pain or solve it by taking medicine.

For those with complete paralysis, the problem will not be noticed at all. The AD response, however, still takes place and that can lead to dangerously high blood pressure levels causing tissue damage and even permanent brain injury if left untreated.

3. Spasticity

For some patients, there may be an increase in spasticity or muscle twitching because of the pain and discomfort.

How Heterotopic Ossification is diagnosed

There are a range of different diagnostic tools that can be used if Heterotopic Ossification is suspected. There may well be physical signs but diagnosis can be quickly confirmed using blood testing, a CT scan, ultrasound, x-ray or a 3-phase bone scan.

Heterotopic Ossification Treatment Options

  • HO itself is not that well understood and it is difficult, therefore, to put in measures which will help reduce the potential for it occurring in the first place.
  • Medications like blood thinner (warfarin), which contain Vitamin K, can help promote healthy bones.
  • Non-steroidal anti-inflammatory drugs may also help prevent abnormal growths from starting.
  • When HO is identified, a drug like warfarin may be used to slow down progress but this only really works at the start of ossification. Pulse low-intensity electromagnetic field therapy has also been shown to slow the development of HO.
  • Surgery can be used, but is generally seen as a last resort. This is because blood loss is common during the operation and it also does not guarantee that HO will not return at a later date.

For many, the treatment for HO is about finding what works for the individual. It’s important to stay vigilant following an SCI and see a physician if this condition is suspected.