ARTIFICIAL LUMBAR DISC REPLACEMENT
The spine is composed of a series of bones called vertebrae. There are different areas of the spine, defined by their curvature and function. The lumbar spine is located at and below your waist. The lumbar spine contains five large vertebrae.
The back part of each vertebra arches to form the lamina. The lamina creates a roof-like cover over the back opening in each vertebra. The opening in the center of each vertebra forms the spinal canal. The spinal cord, nerves, and arteries travel through the protective spinal canal. The spinal cord and nerves send messages between your body and brain.
Intervertebral discs are located in between the vertebrae. Strong connective tissue forms the discs. Their tough outer layer is the annulus fibrosus. Their gel-like center is the nucleus pulposus. A healthy disc contains about 80% water.
The discs and two small spinal facet joints connect one vertebra to the next. The discs and joints allow movement and provide stability. The discs also act as a shock-absorbing cushion to protect the vertebrae.
Degenerative disc disease can occur in any part of the spine. Aging can cause the discs to lose fluid, collapse, or rupture. This decreases the space between the vertebrae. As the disc deteriorates, it affects the structure of the vertebrae. Such changes can lead to conditions that put pressure on the spinal cord and nerves. Doctors treat most symptoms of pain non-surgically. However, doctors recommend surgery if the spine is unstable or when pain is not controlled by other means.
Normally, the intervertebral discs act as a cushion between the vertebrae. When a disc degenerates, it can become painful. Abnormal bone growths called bone spurs can grow in the joint and enter the spinal canal. A damaged disc can pinch nerves and cause chronic low back pain, burning, tingling, pressure, weakness, and numbness. Symptoms of pain and weakness may spread to the legs (sciatica).
In rare cases, the loss of bowel and bladder control indicates a possible serious problem. In this rare case, you should seek immediate medical attention.
Your doctor can diagnose a degenerative disc by performing a physical examination and viewing medical images. You will be asked to perform simple movements to help your doctor assess your muscle strength, joint motion, and stability. Since the nerves from the spine travel to the body, your doctor will perform a neurological examination of your arms and legs to see how the nerves are functioning.
X-rays will be done to see the condition of the vertebrae in your spine. Sometimes doctors inject dye into the spinal column to enhance the X-ray images in a procedure called a myelogram. A myelogram can indicate if there is pressure on the spinal cord or nerves from herniated discs, bone spurs, or tumors.
A computed tomography (CT) scan may be done with or without a myelogram to see the shape and size of your spinal canal and the structures around it. A discogram, which involves injecting dye directly into the disc, provides a view of the internal structure of a disc and can help identify if it is a source of pain. Magnetic resonance imaging provides the most detailed views of the discs, ligaments, spinal cord, nerve roots, or tumors.
Most people with degenerative disc disease are treated with non-surgical methods aimed at pain relief. Non-surgical treatments for degenerative disc disease are designed to relieve pain and restore function, but they cannot correct structural deformities in the lumbar spine. Surgery is recommended when non-surgical treatments have provided minimal or no improvement of your symptoms. Traditionally, spinal fusion surgery is used to remove the degenerative disc and fuse or secure two or more vertebrae together. Spinal fusion surgery results in movement limitations. An alternative to spinal fusion surgery is artificial lumbar disc replacement.
The goal of artificial lumbar disc replacement is to relieve pain while maintaining motion, reduce further degeneration in the spine, and allow people to return to activities quickly. There are several types of artificial lumbar discs, and your surgeon will discuss the most appropriate ones for you.
Artificial lumbar disc replacement is an inpatient procedure. To begin the procedure, the surgeon makes a small incision in the abdomen to access the front part of the lumbar spine. The surgeon removes the damaged disc and related tissue from the lumbar spine. The vertebral space is opened to the normal disc height to relieve pressure on nerves.
Next, the surgeon places the artificial disc made of two endplates and a sliding disc. The surgeon secures the metal endplates to the bones. The artificial disc is placed between the two endplates. This part of the surgery is performed under X-ray guidance (fluoroscopy). The spine is positioned in the normal posture and the position of the artificial disc is checked.
A hospital stay is followed by about 4-6 weeks of outpatient physical therapy and a walking regime, designed to improve strength, endurance, and flexibility. Recovery from artificial disc replacement is usually faster than with fusion surgery. The artificial lumbar disc allows natural motions of the spine, including flexion, extension, rotation, and side bending.