Artificial Disk Replacement in the Lumbar Spine

Artificial Disk Replacement in the Lumbar Spine

Article Featured on AAOS
In artificial disk replacement, worn or damaged disk material between the small bones in the spine (vertebrae) is removed and replaced with a synthetic or “artificial” disk. The goal of the procedure is to relieve back pain while maintaining more normal motion than is allowed with some other procedures, such as spinal fusion.

Artificial disk replacements

 

Total artificial disk replacements are mechanical devices that simulate spinal function. CHARITÉ artificial disk. Reproduced with permission from DePuy Spine, Inc. © 2007 DePuy Spine, Inc. All rights reserved.

Lumbar Fusion and Artificial Disk Replacement

Although it is estimated that 70% to 80% of people will experience low back pain at some point in their lives, most will not need surgery to improve their pain. Surgery is considered when low back pain does not improve with conservative treatment.

For patients who have exhausted nonsurgical options and are still in pain, lumbar fusion surgery remains the most common option for treating low back pain. Fusion is essentially a “welding” process. The basic idea is to fuse together the painful vertebrae so that they heal into a single, solid bone.

While many patients are helped by lumbar fusion, the results of the surgery can vary. In addition, some patients whose fusion surgeries heal perfectly still end up with no improvement of their back pain.

Some doctors believe that the failure to improve after fusion surgery is due to the fact that fusion prevents normal motion in the spine. For this reason, artificial disk replacement—which aims to preserve normal motion—has emerged as an alternative treatment option for low back pain.

Artificial disk replacement initially gained FDA approval for use in the U.S. in 2004. Over the past several years, numerous disk replacement designs have been developed and are currently being tested.

X-rays of lumbar spinal fusion and disk replacement

These x-rays, taken from the side, show patients treated with (left) lumbar spinal fusion, and (right) artificial disk replacement. (Right) From Mathur S, Jenis LG, An HS: Surgical Management of Chronic Low Back Pain: Arthrodesis, in Jenis LG, ed: Low Back Pain: Monograph Series. (Left) From Jenis LG: Surgical Management of Chronic Low Back Pain: Alternatives to Arthrodesis, in Jenis LG, ed: Low Back Pain: Monograph Series. Rosemont, IL, Amer Acad of Orthop Surg, 2005.

Who Is a Candidate for Disk Replacement?

To determine if you are a good candidate for disk replacement, your surgeon may require a few tests, including:

  • Magnetic resonance imaging (MRI) scans
  • Discography
  • Computed tomography (CT) scans
  • X-rays

Information from these tests will also help your surgeon determine the source of your back pain.

Artificial disk replacement is not appropriate for all patients with low back pain. In general, good candidates for disk replacement have the following characteristics:

  • Back pain caused by one or two problematic intervertebral disks in the lumbar spine
  • No significant facet joint disease or bony compression on spinal nerves
  • Body size that is not excessively overweight
  • No prior major surgery on the lumbar spine
  • No deformity of the spine (scoliosis)

Surgical Procedure

Most artificial disk replacement surgeries take from 2 to 3 hours.

Your surgeon will approach your lower back from the front through an incision in your abdomen. With this approach, the organs and blood vessels must be moved to the side. This allows your surgeon to access your spine without moving the nerves. Usually, a vascular surgeon assists the orthopaedic surgeon with opening and exposing the disk space.

During the procedure, your surgeon will remove your problematic disk and then insert an artificial disk implant into the disk space.

Disk Design

Some disk replacement devices comprise the nucleus (center) of the intervertebral disk while leaving the annulus (outer ring) in place, although this technology is still in an investigative stage.

In most cases, total artificial disk replacements substitute both the annulus and nucleus with a mechanical device that will simulate spinal function.

There are a number of different disk designs. Each is unique in its own way, but all maintain a similar goal: to reproduce the size and function of a normal intervertebral disk.

Some disks are made of metal, while others are a combination of metal and plastic, similar to joint replacements in the knee and hip. Materials used include medical grade plastic (polyethylene) and medical grade cobalt chromium or titanium alloy.

Your surgeon will talk with you about which disk design is best for you.

Examples of artificial disk replacements

Examples of total artificial disk replacements. A. CHARITÉ artificial disk. Reproduced with permission from DePuy Spine, Inc. © 2007 DePuy Spine, Inc. All rights reserved. B. ProDisc-L prostheses. Reproduced with permission from Synthes, West Chester, PA.

Recovery

In most cases, you will stay in the hospital for 1 to 3 days following artificial disk replacement. The length of your stay will depend upon how well-controlled your pain is and your return to function.

In most cases, patients are encouraged to stand and walk by the first day after surgery. Because bone healing is not required following artificial disk replacement, the typical patient is encouraged to move through the mid-section. Early motion in the trunk area may lead to quicker rehabilitation and recovery.

You will perform basic exercises, including routine walking and stretching, during the first several weeks after surgery. During this time, it is important to avoid any activities that cause you to hyperextend your back.

Outcomes

Most patients can expect improvement of lower back pain and disability in weeks to months following surgery. Studies show that disk replacement improves, but does not completely eliminate pain. Before your surgery, it is important to talk with your surgeon about realistic expectations for pain relief.

Research On the Horizon

The future of artificial disk replacement technology will likely include advancements in the design of implants and tools for diagnosing the source of pain, as well as the development of ways to return the disk to normal function without the insertion of any biomechanical device.

Although no longer considered a new technology, the development of artificial disk replacement is more recent than that of lumbar fusion. Follow-up studies to 10 years have shown satisfactory outcomes in a carefully chosen patient population. Despite the theoretical advantages of preserving motion, some studies have not shown a clear advantage of artificial disk replacement over lumbar fusion. Research continues on the outcomes of the procedure.


New Mexico Orthopaedics is a multi-disciplinary orthopaedic clinic located in Albuquerque New Mexico. We have multiple physical therapy clinics located throughout the Albuquerque metro area.

New Mexico Orthopaedics offers a full spectrum of services related to orthopaedic care and our expertise ranges from acute conditions such as sports injuries and fractures to prolonged, chronic care diagnoses, including total joint replacement and spinal disorders.

Because our team of highly-trained physicians specialize in various aspects of the musculoskeletal system, our practice has the capacity to treat any orthopaedic condition, and offer related support services, such as physical therapy, WorkLink and much more.

If you need orthopedic care in Albuquerque New Mexico contact New Mexico Orthopaedics at 505-724-4300.

Cervical Spondylotic Myelopathy (Spinal Cord Compression)

Cervical Spondylotic Myelopathy (Spinal Cord Compression)

Article Featured on AAOS

Cervical spondylotic myelopathy (CSM) is a neck condition that arises when the spinal cord becomes compressed—or squeezed—due to the wear-and-tear changes that occur in the spine as we age. The condition commonly occurs in patients over the age of 50.

Because the spinal cord carries nerve impulses to many regions in the body, patients with CSM can experience a wide variety of symptoms. Weakness and numbness in the hands and arms, loss of balance and coordination, and neck pain can all result when the normal flow of nerve impulses through the spinal cord is interrupted.

Anatomy

Your spine is made up of 24 bones, called vertebrae, that are stacked on top of one another. The seven small vertebrae that begin at the base of the skull and form the neck comprise the cervical spine.

The areas of the spine

Cervical spondylotic myelopathy occurs in the cervical spine—the seven small vertebrae that form the neck

Other parts of your spine include:

Spinal cord and nerves. The spinal cord extends from the skull to your lower back and travels through the middle part of each stacked vertebra, called the central canal. Nerves branch out from the spinal cord through openings in the vertebrae (foramen) and carry messages between the brain and muscles.

Spinal nerve root

Spinal nerve root.

Intervertebral disks. In between your vertebrae are flexible intervertebral disks. They act as shock absorbers when you walk or run.

Intervertebral disks are flat and round and about a half inch thick. They are made up of two components:

  • Annulus fibrosus. This is the tough, flexible outer ring of the disk.
  • Nucleus pulposus. This is the soft, jelly-like center of the disk.

Cause

Cervical spondylotic myelopathy (CSM) arises from degenerative changes that occur in the spine as we age. These degenerative changes in the disks are often called arthritis or spondylosis.

Cervical Disk Degeneration

Bone spurs. As the disks in the spine age, they lose height and begin to bulge. They also lose water content, begin to dry out, and become stiffer. This problem causes settling, or collapse, of the disk spaces and loss of disk space height.

As the disks lose height, the vertebrae move closer together. The body responds to the collapsed disk by forming more bone—called bone spurs—around the disk to strengthen it. These bone spurs contribute to the stiffening of the spine. They may also make the spinal canal narrow—compressing or squeezing the spinal cord.

Illustrations of a healthy cervical vertebra and disk and a disk that has collapsed

(Left) Side view of a healthy cervical vertebra and disk. (Right) A disk that has degenerated and collapsed.

Herniated disk. A disk herniates when its jelly-like center (nucleus pulposus) pushes against its outer ring (annulus fibrosus). If the disk is very worn or injured, the nucleus may squeeze all the way through. When a herniated disk bulges out toward the spinal canal, it can put pressure on the spinal cord or nerve roots.

As disks deteriorate with age, they become more prone to herniation. A herniated disk often occurs with lifting, pulling, bending, or twisting movements.

Cross-section and side views of a herniated disk

Herniated disk (cross-section and side views)

Other Causes of Myelopathy

Myelopathy can arise from other conditions that cause spinal cord compression, as well. Although these conditions are not related to disk degeneration, they may result in the same symptoms as CSM.

Rheumatoid arthritis. Rheumatoid arthritis is an autoimmune disease. This means that the immune system attacks its own tissues. In rheumatoid arthritis, immune cells attack the synovium, the thin membrane that lines the joints.

As the synovium swells, it may lead to pain and stiffness and, in severe cases, destruction of the facet joints in the cervical spine. When this occurs, the upper vertebra may slide forward on top of the lower vertebra, reducing the amount of space available for the spinal cord.

Injury. An injury to the neck—such as from a car accident, sports, or a fall—may also lead to myelopathy.

For example, a “rear end” car collision may result in hyperextension, a backward motion of the neck beyond its normal limits, or hyperflexion, a forward motion of the neck beyond its normal limits. Because these types of injuries often affect the muscles and ligaments that support the vertebrae, they may lead to spinal cord compression.

Symptoms

Typically, the symptoms of CSM develop slowly and progress steadily over several years. In some patients, however, the condition may worsen more rapidly.

Patients with CSM may experience a combination of the following symptoms:

  • Tingling or numbness in the arms, fingers, or hands
  • Weakness in the muscles of the arms, shoulders, or hands. You may have trouble grasping and holding on to items.
  • Imbalance and other coordination problems. You may have trouble walking or you may fall down. With myelopathy, there is no sensation of spinning, or “vertigo.” Rather, your head and eyes feel steady, but your body feels unable to follow through with what you are trying to do.
  • Loss of fine motor skills. You may have difficulty with handwriting, buttoning your clothes, picking up coins, or feeding yourself.
  • Pain or stiffness in the neck

Doctor Examination

Physical Examination

After discussing your medical history and general health, your doctor will ask you about your symptoms. He or she will conduct a thorough examination of your neck, shoulders, arms, hands, and legs, looking for:

  • Changes in reflexes—including the presence of hyper-reflexia, a condition in which reflexes are exaggerated or overactive
  • Numbness and weakness in the arms, hands, and fingers
  • Trouble walking, loss of balance, or weakness in the legs
  • Atrophy—a condition in which muscles deteriorate and shrink in size

Tests

X-rays. These provide images of dense structures, such as bone. An x-ray will show the alignment of the vertebrae in your neck.

Magnetic resonance imaging (MRI) scans. These studies create better images of the body’s soft tissues. An MRI can show spinal cord compression and help determine whether your symptoms are caused by damage to soft tissues—such as a bulging or herniated disk.

MRI scan of a herniated disk pressing on spinal cord

This MRI image shows herniated disks pressing on the spinal cord (red arrows). Reproduced from Boyce R, Wang J: Evaluation of neck pain, radiculopathy and myelopathy: imaging, conservative treatment, and surgical indications. Instructional Course Lectures 52. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2003, pp.489-495.

Computed tomography (CT) scans. More detailed that a plain x-ray, a CT scan can show narrowing of the spinal canal and can help your doctor determine whether you have developed bone spurs in your cervical spine.

CT scan showing narrowing of the spinal canal due to bone spurs

This CT scan shows bone spurs that have led to narrowing of the spinal canal (arrows).

Myelogram. This is a special type of CT scan. In this procedure, a contrast dye is injected into the spinal column to make the spinal cord and nerve roots show up more clearly.

Treatment

Nonsurgical Treatment

In milder cases, initial treatment for CSM may be nonsurgical. The goal of nonsurgical treatment is to decrease pain and improve the patient’s ability to perform daily activities. Nonsurgical treatment options include:

Soft cervical collar. This is a padded ring that wraps around the neck and is held in place with velcro. Your doctor may advise you to wear a soft cervical collar to allow the muscles of the neck to rest and limit neck motion. A soft collar should only be worn for a short period of time since long-term wear may decrease the strength of the muscles in your neck.

Physical therapy. Specific exercises can help relieve pain, strengthen neck muscles, and increase flexibility. Physical therapy can also help you maintain strength and endurance so that you are better able to perform your daily activities. In some cases, traction can be used to gently stretch the joints and muscles of the neck.

Medications. In some cases, medications can help improve your symptoms.

  • Nonsteroidal anti-inflammatory medications (NSAIDs). Drugs like aspirin, ibuprofen, and naproxen can help relieve pain from reduce inflammation.
  • Oral corticosteroids. A short course of oral corticosteroids may help relieve pain by reducing inflammation.
  • Epidural steroid injection. Although not often used to treat CSM, in this procedure, steroids are injected into the space next to the covering of the spinal cord (the “epidural” space) to help reduce local inflammation. Although a steroid injection may temporarily help relieve pain and swelling, it will not relieve pressure on the spinal cord.
  • Narcotics. These medications are reserve for patients with severe pain that is not relieved by other options. Narcotics are usually prescribed for a limited time only.

Although people sometimes turn to chiropractic manipulation for neck and back pain, manipulation should never be used for spinal cord compression.

Surgical Treatment

If nonsurgical treatment does not relieve your symptoms, your doctor will talk with you about whether you would benefit from surgery. The majority of patients with symptoms and tests consistent with CSM are recommended to have surgery.

There are several procedures that can be performed to help relieve pressure on the spinal cord. The procedure your doctor recommends will depend on many factors, including what symptoms you are experiencing and the levels of the spinal cord that are involved.


New Mexico Orthopaedics is a multi-disciplinary orthopaedic clinic located in Albuquerque New Mexico. We have multiple physical therapy clinics located throughout the Albuquerque metro area.

New Mexico Orthopaedics offers a full spectrum of services related to orthopaedic care and our expertise ranges from acute conditions such as sports injuries and fractures to prolonged, chronic care diagnoses, including total joint replacement and spinal disorders.

Because our team of highly-trained physicians specialize in various aspects of the musculoskeletal system, our practice has the capacity to treat any orthopaedic condition, and offer related support services, such as physical therapy, WorkLink and much more.

If you need orthopedic care in Albuquerque New Mexico contact New Mexico Orthopaedics at 505-724-4300.

An Experts Guide to Avoiding Back Pain

Deciding whether to have spine surgery

By Alan S. Hilibrand, MD | Featured on AAOS

Orthopaedic surgeons encourage “shared decision-making” when it comes to treating patients, because the doctor and patient each provide information needed to make a decision about surgery.

Read more

The Best Exercises for Spinal Cord Injury Survivors

The Best Exercises for Spinal Cord Injury Survivors

By Erin Jones | Article Featured on US News

AFTER A SPINAL CORD injury, it’s no surprise that life changes. Even daily tasks, like getting dressed in the morning, may become more difficult. Depending on a patient’s injury, however, certain exercises can help those with spinal cord injuries improve function and adapt to using a wheelchair.

Read more

Back pain is extremely common, and surgery often fails to relieve it. Find out why your back hurts and whether surgery might help.

Back surgery: When is it a good idea?

Back pain is extremely common, and surgery often fails to relieve it. Find out why your back hurts and whether surgery might help.

Back surgery can help relieve some causes of back pain, but it’s rarely necessary. Most back pain resolves on its own within three months.

Low back pain is one of the most common ailments seen by family doctors. Back problems typically respond to nonsurgical treatments — such as anti-inflammatory medications, heat and physical therapy.

Back surgery might be an option if conservative treatments haven’t worked and your pain is persistent and disabling. Back surgery often more predictably relieves associated pain or numbness that goes down one or both arms or legs.

These symptoms often are caused by compressed nerves in your spine. Nerves may become compressed for a variety of reasons, including:

  • Disk problems. Bulging or ruptured (herniated) disks — the rubbery cushions separating the bones of your spine — can sometimes press too tightly against a spinal nerve and affect its function.
  • Overgrowth of bone. Osteoarthritis can result in bone spurs on your spine. This excess bone most commonly affects the hinge joints on the back part of the spinal column and can narrow the amount of space available for nerves to pass through openings in your spine.

It can be very difficult to pinpoint the exact cause of your back pain, even if your X-rays show that you have disk problems or bone spurs. X-rays taken for other reasons often reveal bulging or herniated disks that cause no symptoms and need no treatment.

Different types of back surgery include:

  • Diskectomy. This involves removal of the herniated portion of a disk to relieve irritation and inflammation of a nerve. Diskectomy typically involves full or partial removal of the back portion of a vertebra (lamina) to access the ruptured disk.
  • Laminectomy. This procedure involves the removal of the bone overlying the spinal canal. It enlarges the spinal canal and is performed to relieve nerve pressure caused by spinal stenosis.
  • Fusion. Spinal fusion permanently connects two or more bones in your spine. It can relieve pain by adding stability to a spinal fracture. It is occasionally used to eliminate painful motion between vertebrae that can result from a degenerated or injured disk.
  • Artificial disks. Implanted artificial disks are a treatment alternative to spinal fusion for painful movement between two vertebrae due to a degenerated or injured disk. But these relatively new devices aren’t an option for most people.

Before you agree to back surgery, consider getting a second opinion from a qualified spine specialist. Spine surgeons may hold different opinions about when to operate, what type of surgery to perform and whether — for some spine conditions — surgery is warranted at all. Back and leg pain can be a complex issue that may require a team of health professionals to diagnose and treat.


New Mexico Orthopaedics is a multi-disciplinary orthopaedic clinic located in Albuquerque New Mexico. We have multiple physical therapy clinics located throughout the Albuquerque metro area.

New Mexico Orthopaedics offers a full spectrum of services related to orthopaedic care and our expertise ranges from acute conditions such as sports injuries and fractures to prolonged, chronic care diagnoses, including total joint replacement and spinal disorders.

Because our team of highly-trained physicians specialize in various aspects of the musculoskeletal system, our practice has the capacity to treat any orthopaedic condition, and offer related support services, such as physical therapy, WorkLink and much more.

If you need orthopedic care in Albuquerque New Mexico contact New Mexico Orthopaedics at 505-724-4300.

albuquerque, new mexico, orthopaedic doctors

New Surgical Strategy Offers Hope for Repairing Spinal Injuries

Article Found on MedicalNewsToday

Surgery to reconnect sensory neurons to the spinal cord after a traumatic spinal injury works because offshoots from the spinal cord complete the spinal circuit.

Scientists in the UK and Sweden previously developed a new surgical technique to reconnect sensory neurons to the spinal cord after traumatic spinal injuries. Now, they have gained new insight into how the technique works at a cellular level by recreating it in rats with implications for designing new therapies for injuries where the spinal cord itself is severed. Read more

new mexico, orthopaedic doctors, albuquerque

How the Spinal Cord Works

Article Found on ChristopherReeve.org

What is the central nervous system?

The central nervous system (CNS) controls most functions of the body and mind. It consists of two parts: the brain and the spinal cord.

The brain is the center of our thoughts, the interpreter of our external environment, and the origin of control over body movement. Like a central computer, it interprets information from our eyes (sight), ears (sound), nose (smell), tongue (taste), and skin (touch), as well as from internal organs such as the stomach.

The spinal cord is the highway for communication between the body and the brain. When the spinal cord is injured, the exchange of information between the brain and other parts of the body is disrupted. Read more

Learn About Spinal Cord Injuries

Learn About Spinal Cord Injuries

Article Featured on Shepherd Center

Every year, about 12,000 people sustain a spinal cord injury. That’s 30 new injuries every day. Most of these people are injured in auto and sports-related accidents, falls and industrial mishaps. An estimated 60 percent of these individuals are 30 years old or younger, and the majority of them are men.

Read more

Spinal Cord Injury

Spinal Cord Injury Symptoms

A spinal cord injury — damage to any part of the spinal cord or nerves at the end of the spinal canal — often causes permanent changes in strength, sensation and other body functions below the site of the injury.

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