Osteoporotic vertebral fractures
Definition
Fragility fractures occur in the spine bones (vertebrae) weakened by an underlying disease. The most common cause of these fractures is osteoporosis.
Unlike fractures in healthy bones that happen after high-energy traumas, road accidents or falls from height, fragility fractures may occur with minimal trauma or even with no trauma at all.
Basic anatomy of normal and fractured spine
The spine is made of twenty-five bones (vertebrae) stacked on top of each other. The vertebra is filled with the spongy cancellous bone, which is surrounded by dense cortical bone.
Normal bone is able to resist considerable forces, but in osteoporosis the bone is so soft it resembles a rice crispy treat.
When a vertebral fracture occurs, the spongy cancellous bone is squished together, and the vertebral body collapses, turning from rectangular into a wedge shape.
In the more complicated cases the vertebra may not only collapse, but also expand to the sides sometimes even pushing on the nerves. This is called a burst fracture.
Symptoms of vertebral fractures
Pain is the usual presenting symptom of a vertebral fracture, even though in many cases a fracture may go unnoticed.
In the presence of multiple vertebral fractures, height loss may become noticeable. The affected person may also develop a round back or a back hump.
Pressure on the nerves is uncommon with vertebral fractures but may develop if bone fragments are pushed inside the spinal canal with a burst fracture. These patients may develop pain in the legs, numbness and weakness, and even difficulties with bladder and bowel function.
Diagnosis of vertebral fractures and additional studies
Pain may suggest presence of a vertebral fracture. The diagnosis is then confirmed with additional imaging studies. The initial two studies usually include X-ray and MRI.
- X-ray may demonstrate changed shape of the broken vertebra;
- MRI will show increased swelling inside the fractured vertebra confirming the fracture is new;
At times, other studies are needed:
- CT scan may be used if surgery is planned. It visualizes bones in greater detail and may help distinguish between a simple compression fracture and a burst fracture;
- Scintigraphy (also called nuclear bone scan or Technetium bone scan) is used when MRI is contraindicated (certain heart devices, metal in some body organs). It also helps distinguish new from old fractures and may help identify bone tumors causing the fracture;
- Bone density test (called DEXA), as the name implies, studies density of the bones and is used to diagnose osteoporosis.
What other conditions can cause vertebral fractures?
While osteoporosis is the most common cause of the low energy spine fractures, other more serious conditions may cause weakness of bones:
- Spine tumors, like multiple myeloma or metastases of tumors from other organs;
- Infections.
Additional studies like CT, MRI and blood work are done to rule out these conditions.
Natural history of osteoporotic vertebral fractures: is surgery always recommended?
Most osteoporotic fractures will heal by themselves within six to twelve weeks. As the fracture heals, pain gradually subsides. For this reason, most people will not require any treatments apart from light pain medications.
If pain does not improve after several weeks or if pain is intolerable, there is an option to stabilize the fracture injecting acrylic bone cement into the vertebra (procedure called kyphoplasty).
Conservative treatment of osteoporotic vertebral fractures
It is recommended to stay as active as possible because decreased physical activity has its own risks including problems with breathing, heart function and blood clots.
Light pain medications are used during the period of bone healing.
Back braces are not typically used since they may lead to muscle atrophy.
While dealing with the fractures, it is important to treat the underlying cause, osteoporosis.
When is surgery needed for vertebral fractures?
There are three indications for surgery:
- Severe pain or pain that is not getting better after several weeks;
- Unstable fracture of spine;
- Pressure on nerve structures.
What kinds of surgery are available to address vertebral fractures?
Depending on the kind of fracture, there are three available surgeries:
- Vertebral augmentation (kyphoplasty or vertebroplasty), when acrylic cement is injected in the broken bone to stabilize its fragments;
- Spinal fusion or stabilization with screws and rods, if the broken vertebra is not able to support the whole spine;
- Open spinal decompression, if the fragments of broken bone push on the nerve structures.
