Avascular Necrosis: What is it?

Kummel disease a rare type of AVN or vertebral osteonecrosis can affect the spine.

Avascular necrosis (AVN) develops when a bone loses its blood supply. AVN goes by several other names, including Kummel disease, osteonecrosis, aseptic necrosis, and ischemic bone necrosis. AVN typically affects bone in the hips, thighs, knees and shoulders—although it can develop in any bone in the body.

Kummel disease is a rarely occurring variation of avascular necrosis that can affect the spine’s vertebrae, usually the thoracic spine (mid back) region. There are many different spine-related disorders that can contribute to disrupting a vertebral body’s blood supply, such as infection, osteoporosis, radiation therapy, steroid use, and metastatic spine tumors. Like other organs in the body, bone needs a healthy blood supply to rebuild itself, stay strong and support the spinal column.
Vertebral avascular necrosisVertebral avascular necrosis. By Mikael Häggström [CC0], from Wikimedia CommonsA consequence of any of these disorders that can disrupt the blood supply to the spine’s vertebrae is vertebral compression fracture, sometimes called a fragility fracture. The bone may weaken to the point that a seemingly minor injury results in a compression or wedge-shaped fracture or multiple fractures that can lead to kyphosis, a type of spinal deformity.

Though Kummell disease is rare, researchers believe it’s becoming more prevalent as the aging population grows. People with osteoporosis and older adults are at a greater risk for developing this disorder.

Avascular Necrosis and Kummel Disease Share Some Similar Causes and Risk Factors

  • Injury: This is known as trauma-related avascular necrosis. A broken hip or vertebral fracture may lead to osteonecrosis.
  • Increased pressure within the bone: The pressure within the bone causes the blood vessels to narrow, making it hard for the vessels to deliver enough blood to the bone cells.
  • Certain risk factors: This is known as non-traumatic avascular necrosis. These risks include medical conditions and lifestyle choices that affect bone metabolism or bone remodeling.

AVN has several risk factors, including medical conditions and lifestyle choices that may increase your chances of developing the disorder:

  • Heavy alcohol use
  • Long-term corticosteroid use
  • Osteoporosis
  • Blood clots and arterial inflammation
  • Blood disorders (such as Sickle cell disease)
  • Radiation and chemotherapy
  • Pancreatitis
  • Gaucher disease (occurs when high amounts of fatty substances collect in the organs)
  • Decompression sickness (a condition causing gas bubbles in the blood)

How Doctors Diagnose Avascular Necrosis

Diagnosing spinal AVN caused by trauma—also called Kummell disease—begins with a thorough review of your medical history and symptoms. This is all part of your physical exam.

After your physical exam, your doctor may order imaging scans to better see changes in your vertebrae. Below are some of the tools your doctor may use to diagnose Kummell disease:

  • X-ray: This first-line imaging test can illuminate problems with your spinal bones. It’s not able to show early-stage bone problems, though.
  • Computed tomography (CT) scan: A CT scan provides a 3-dimensional picture of your bone. It also shows "slices" of bone, making the picture clearer than what x-rays and bone scans deliver.
  • Magnetic resonance imaging (MRI): This technology can produce very detailed images of your soft tissues and bones. The test is sensitive enough to see bone problems at their earliest onset, which x-ray is unable to do.
  • Bone scan: Also known as skeletal scintigraphy, bone scans are often used in people who have normal x-rays. A radioactive dye is injected into your affected bone and a picture of your bone is taken with a special camera. The picture shows how the dye travels through your bone and where normal bone formation is occurring.
  • Biopsy: A biopsy is a surgical procedure in which tissue from your affected bone is removed and studied. Although a biopsy is a conclusive way to diagnose AVN, it is rarely used because it requires surgery.
  • Functional evaluation of bone: Tests to measure the pressure inside a bone may be used when your doctor strongly suspects that you have AVN, despite normal x-ray, bone scan, and MRI results. These tests are very sensitive at detecting increased pressure within your bone, but they require surgery.

How Is Avascular Necrosis Treated?

The goals of treatment for AVN include improving your use of the affected joint, stopping further damage to the bone, and ensuring bone and joint survival.

If you have an early-stage form of Kummell disease, your doctor may prescribe medications to manage pain and/or inflammation. Physical therapy (PT) may be included in your treatment plan. A physical therapist can teach you how to exercise safely to protect your joints and bones while building strength, flexibility and endurance.

Though non-surgical treatments may help keep pain at bay, they are generally a temporary solution for people with Kummel disease. In many cases, spine surgery is necessary to prevent the condition from progressing to a point that it harms your quality of life.

Spine surgery for Kummel disease may have several purposes, depending on your specific symptoms. As such, your surgeon may use a single surgical approach or combine techniques to give you the best possible outcome. For example:

  • If you have developed abnormal kyphosis, your doctor may recommend osteotomy (surgical removal of bone) combined with spinal instrumentation and fusion. This combination of surgical procedures can reduce the size of the kyphotic curve, realign the spine and stabilize it.
  • Some patients with Kummel disease have pain and neurological symptoms, such as numbness or weakness. If symptoms are caused by nerve compression, a spinal decompression surgery (such as a foraminotomy) may be recommended to relief pressure on pinched nerves and prevent potentially permanent nerve damage.

Another surgical option for AVN is known as core decompression. This procedure involves removing the inner layer of bone, which reduces pressure within the bone, increases blood flow to the bone, and allows more blood vessels to form.

Core decompression works best in people who are in the earliest stages of avascular necrosis, often before the collapse of a joint. This procedure may reduce pain and slow progression of bone and joint destruction.

After core decompression, your surgeon may implant bone graft to help stimulate new bone growth and healing. Bone graft transplants healthy bone from a part of the body, such as the leg, to the diseased area. Several synthetic bone grafts are also available. Depending on the location and extent of the surgery, expect a lengthy recovery period, usually from 6 to 12 months.

As with all areas of medicine, researchers are continuously exploring treatments that may help people with AVN. One area of interest is therapies that increase the growth of new bone and blood vessels. These treatments have been used experimentally alone and in combination with other treatments, such as osteotomy and core decompression.

Your doctor will work with you to develop a custom treatment plan that addresses your symptoms and medical history.

Your Outlook with Avascular Necrosis (Kummel Disease)

For most people with avascular necrosis (also known as osteonecrosis, aseptic necrosis, and ischemic bone necrosis), treatment is an ongoing process. Your doctor may first recommend the least invasive approach and observe how you respond before progressing you to more substantial AVN therapies. If your condition affects your spinal vertebrae and was caused by trauma or injury (Kummell disease), several treatments may help prevent complications like spinal fracture, kyphosis deformity, and nerve pain from disrupting your life.

Updated on: 06/13/18
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Avascular Necrosis: Risk Factors, Diagnosis and Treatment

Avascular necrosis of the spine is called vertebral osteonecrosis or Kummell disease. It is a rare condition usually affecting the thoracic spine.
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