Disc replacement, whether in the neck or the low back, consists of removing the disc which is the soft portion that joins the vertebral bodies at the front of the spine. In the past, fusions were carried out, in which a material or bone graft was placed in between the vertebral bodies to eliminate motion. The exact opposite happens when we carry out a disc replacement. A disc replacement is made of similar material as total hips and total knees, but the field is rapidly changing.
There are newer materials that are MRI compatible, which means that one can still obtain an MRI scan without resorting to the invasive diagnostic procedures where a needle and dye are placed into the spinal canal with a myelogram CAT scan. Yet another advancement has been in the development of a disc that acts more like our normal disc that will have some compressibility or shock absorption.
Artificial Disc Replacement (ADR), also called Total Disc Replacement (TDR), can be an optimal solution if you have disabling pain from disc degeneration in the low back or neck. Texas Back Institute brought this technology to the United States and performed the first ADR procedure here in 2000. Our surgeons were the first to perform lumbar disc replacement in the US, and have published important research papers on cervical and lumbar arthroplasty.
Over the ensuing years, we have successfully implanted thousands of artificial discs in patients suffering from chronic pain, degenerative disc disease, and herniated disc(s). ADRs provide pain relief while preserving motion and are more effective than fusion surgery in producing desired results.
- Degenerative disc disease
- Herniated discs
- Chronic discogenic pain
Texas Back Institute was one of the pioneers in disc replacement, performing the very first one in March of 2000 in the lumbar spine. Since that time, we have participated in almost 14 different FDA trials of both cervical and lumbar disc. Longer-term studies are showing that if you have disc replacement, maintaining the motion of the operating level, that there is less of a chance of needing more surgery in the future, and this is reduced to approximately 3 to 4 times less than if one was to have a fusion.
Physicians at Texas Back Institute have worked as clinical investigators on ProDisc-C, Mobi-C Single Level, and Mobi-C Two Level. We have also been investigators on several other cervical discs that are not yet FDA-approved. These include Simplify Disc Single Level, Simplify Disc Two Level, M-6 Single Level, Discover Disc, and Kineflex.
- Only FDA Approved Cervical Disc for One & Two Levels
- Superior to fusion for two-level disc replacement
The Mobi-C cervical disc is one of the most widely used cervical discs in the world. First implanted in Orleans, France in November 2004, Mobi-C has been implanted in more than 17,000 spinal levels in 25 countries.
A total of 599 patients were involved in the Mobi-C U.S. clinical trial, which represents the largest concurrent clinical trial ever conducted for cervical disc replacement. Mobi-C received FDA approval in August of 2013, making it the first cervical disc with both one and two-level indications.
How the Mobi-C Works
Mobi-C contains patented Mobile Core Technology™ that allows the polyethylene core to slide and rotate inside the disc for self-adjustment to the cervical spine movements. This means that Mobi-C can react to the normal motion in the cervical spine.
Mobi-C provides bone sparing fixation without chisel cuts into the small vertebral bodies of the cervical spine, making it safe for implantation at two levels.
Mobi-C Clinical Trial Results
In the one-level study, Mobi-C demonstrated non-inferiority to ACDF as reflected in the primary composite endpoint. In the two-level study, Mobi-C demonstrated SUPERIORITY to ACDF in the primary composite endpoint. Key results from the two-level study include:
- Overall trial success was 69.7% for Mobi-C and 37.4% for fusion, which represents statistical superiority(p< 0.0001).
- The rate of secondary surgeries at the operating level for Mobi-C was 3.1% versus 11.4% for fusion.
- The percentage of subjects who demonstrated adjacent segment degeneration (determined by x-ray) was:
- 2.9% of Mobi-C patients compared to 18.1% of ACDF patients at the inferior adjacent level
- 13.1% of Mobi-C patients compared to 33.3% of ACDF patients at the superior adjacent level
- Mean return to work time was 20.9 days shorter for Mobi-C patients compared to fusion patients.
- 78.2% of Mobi-C patients showed improvement in the Neck Disability Index (NDI) based on the FDA success criteria versus 61.8% of fusion patients.
ProDisc is a Total Disc Replacement (TDR) technology platform that offers a surgical alternative to spinal fusion. Qualified patients generally suffer from a single-level degenerated disc in the upper (cervical) or lower (lumbar) spine. ProDisc implants are intended to relieve pain while allowing the potential for motion at the diseased spinal segment. Synthes Spine is currently the only company in the United States to offer Total Disc Replacement devices for both the upper and lower spine.
ProDisc L: Total disc replacement for the lower (lumbar) spine (L3-S1)
The ProDisc-L Total Disc Replacement device is intended to treat a single degenerated (diseased) disc in the lower spine (L3-S1). The ProDisc-L implant was designed in collaboration with practicing spine surgeons and has been thoroughly tested in both laboratory and clinical settings.
The ProDisc-L implant allows the potential for motion through its ball and socket design.
- A plastic inlay affixed to a bottom metal endplate forms the ball.
- A polished concave metal surface in the top endplate forms the socket.
- The socket can move over the surface of the ball to allow for controlled and predictable motion.
The ProDisc-L implant is secured to the bones (vertebrae) in the spine with a patented central keel on the top and bottom endplates. A coating has also been applied to all the implant surfaces that contact bone to allow for the bone to grow onto the implant.
The ProDisc I implant, the predecessor of the ProDisc-L implant was first implanted in 1990. The ProDisc-L implant that is used today was introduced outside the United States in 1999. It was approved by the Food and Drug Administration (FDA) for use in the United States in August 2006.
A ProDisc-L IDE clinical study evaluated the ProDisc-L Total Disc Replacement surgery compared to spinal fusion surgery*. The study demonstrated that ProDisc-L surgery is a safe and effective alternative to fusion surgery* for qualified patients.
For more information about the ProDisc-L implant and procedure, please refer to the resources provided on the right. This information is not a replacement for professional medical advice. Only your surgeon is qualified to diagnose and treat your condition. *The ProDisc-L surgery was compared to a “Circumferential” fusion surgery, which involves removing the diseased disc and inserting a disc spacer through an incision in the abdomen, and attaching metal screws and rods to the back of the spine through an incision(s) in the back.
Spinal Surgery – Know your options
Total Disc Replacement surgery with ProDisc is different from traditional spinal fusion surgery. Both surgeries are intended to relieve pain by removing the diseased disc and restoring the height of the affected disc space.
The ProDisc-C Total Disc Replacement device is intended to treat a single degenerated (diseased) disc in the upper spine (C3-C7). The ProDisc-C implant was designed in collaboration with practicing spine surgeons and has been thoroughly tested in both laboratory and clinical settings.
The ProDisc-C implant allows the potential for motion through its ball and socket design.
- A plastic inlay affixed to a bottom metal endplate forms the ball.
- A polished concave metal surface in the top endplate forms the socket.
- The socket can move over the surface of the ball to allow for controlled and predictable motion
The ProDisc-C implant is secured to the bones (vertebrae) in the spine with a patented central keel on the top and bottom endplates. A coating has also been applied to all the implant surfaces that contact bone to allow for the bone to grow onto the implant.
The ProDisc-C was developed using the same design principles as the ProDisc-L implant. The first ProDisc-C Total Disc Replacement surgery was performed in Europe in 2002. It was approved by the Food and Drug Administration (FDA) for use in the United States in December 2007.
A ProDisc-C IDE clinical study evaluated the ProDisc-C Total Disc Replacement surgery compared to spinal fusion surgery*. The study demonstrated that ProDisc-C surgery is a safe and effective alternative to fusion surgery* for qualified patients. For more information about the ProDisc-C IDE Study, refer to the ProDisc-C IDE Study Brochure and talk to your doctor.
This information is not a replacement for professional medical advice. Only your surgeon is qualified to diagnose and treat your condition.
*The ProDisc-C surgery was compared to an ACDF surgery, which involves removing the diseased disc and inserting a spacer into the space through an incision in the front of the neck. A plate and screws are attached to the bones in the front of the spine to hold the spacer in place and to help promote fusion.
The M6 artificial cervical disc offers an innovative option for artificial cervical disc replacement because of its unique design which is based on a natural disc’s qualities.
Engineered to replicate your own disc, the M6 is the only artificial disc that incorporates an artificial nucleus (made from polycarbonate urethane) and a woven fiber annulus (made from polyethylene). The M6 artificial nucleus and annulus are designed to provide the same motion characteristics of a natural disc.
Together, the M6’s artificial nucleus and annulus provide compressive capabilities along with a controlled range of natural motion in all 6 degrees of freedom along each vertebra. This “natural” motion is designed to provide the freedom to move your neck naturally.
The M6 has two titanium outer plates with keels for anchoring the disc into the bone of the vertebral body. These outer plates are coated with a titanium plasma spray that promotes bone growth into the metal plates, providing long-term fixation and stability of the disc in the bone.
Quality of Motion
Quality of Motion assesses how well the motion of an implanted functional spine unit approximates the motion of a healthy one over the entire range of motion, not just its endpoints. Through biomechanical testing, a load vs. angular displacement curve (“kinematic signature”) is generated that allows assessment of the Quality of Motion parameters.
Biomechanical testing with the M6-L artificial lumbar disc has demonstrated equivalent Quality of Motion compared to the healthy disc. The innovative artificial fiber annulus and nucleus construct of the M6-L is the critical component in replicating this physiologic motion, as it is designed to provide the necessary restraint and control needed throughout the spine’s natural range of motion.
C5-C6 Flexion-Extension Load-Displacement Curves
Biomechanical results showing the M6 cervical disc (orange) maintained total ROM (13.5) vs. the intact disc (13.3) with excellent Quality of Motion. The “kinematic signatures” of the intact disc (grey) and M6 cervical disc are nearly identical.
Patwardhan et al. Musculoskeletal Biomechanics Laboratory, Edward Hines Jr. VA Hospital, Hines, Illinois, USA
* This behavior is expected based on a limited cadaver study on the bench, not in-vivo results.
With its unparalleled commitment to the world of spine, Texas Back Institute became the first institution in the United States to prescribe outpatient myelography, led the first FDA study of the artificial disc and later performed the first artificial disc replacement in the United States.
Our surgeons have been pioneers and champions in the advancement of spine surgery covering everything from trauma, deformities and degenerative changes as part of the aging process. Our clinical studies help advance the field of spine care with our primary focus on the relationship between diagnostic evaluations and treatment outcomes. Clinical studies have involved discography, MRIs, minimally invasive procedures and total disc replacement.
- “Long-term clinical and radiographic outcomes of cervical disc replacement with the Prestige disc: results from a prospective randomized controlled clinical trial” posted in the Journal Neurosurgery Spine (Dr. Zigler)
- “Cervical total disc replacement with the Mobi-C cervical artificial disc compared with anterior discectomy and fusion for treatment of 2-level symptomatic degenerative disc disease: a prospective, randomized, controlled multicenter clinical trial” posted in the Journal Neurosurgery Spine (Drs. Hisey and Rashbaum)
- “Prospective, Randomized Comparison of Cervical Total Disc Replacement vs. Anterior Cervical Fusion: Results at 48 Months Follow-up” posted in Journal of Spinal Disorders and Techniques (Dr. Hisey)
- “Comparison of 2 Lumbar Total Disc Replacements: Results of a Prospective, Randomized, Controlled, Multicenter Food and Drug Administration Trial With 24-Month Follow-up” posted in the Spine Journal (Dr. Guyer)
“Results of the prospective, randomized, controlled multicenter Food and Drug Administration investigational device exemption study of the ProDisc-C total disc replacement versus anterior discectomy and fusion for the treatment of 1-level symptomatic cervical disc disease” posted in The Spine Journal (Dr. Zigler)
- “Five-year follow-up of total disc replacement compared to fusion: a randomized controlled trial” posted in the European Spine Journal (Drs. Blumenthal, Zigler, and Guyer)
- “Five-year results of the prospective, randomized, multicenter, Food and Drug Administration investigational device exemption study of the ProDisc-L total disc replacement versus circumferential arthrodesis for the treatment of single-level degenerative disc disease” posted in the Journal Neurosurgery Spine (Dr. Zigler)
- “Five-year adjacent-level degenerative changes in patients with single-level disease treated using lumbar total disc replacement with ProDisc-L versus circumferential fusion” posted in the Journal Neurosurgery Spine (Dr. Zigler)
- “Prospective, Randomized, Multicenter Food and Drug Administration Investigational Device Exemption Study of the ProDisc-L Total Disc Replacement Compared with Circumferential Arthrodesis for the Treatment of Two-Level Lumbar Degenerative Disc Disease” posted in the Journal of Bone and Joint Surgery (Dr. Zigler)
- “A Prospective, Randomized, Multicenter Food and Drug Administration Investigational Device Exemptions Study of Lumbar Total Disc Replacement With the CHARITÉ™ Artificial Disc Versus Lumbar Fusion” posted in the Spine journal (Dr. Blumenthal)
- “Prospective, randomized, multicenter Food and Drug Administration investigational device exemption study of lumbar total disc replacement with the CHARITE´ artificial disc versus lumbar fusion: Five-year follow-up” posted in The Spine Journal (Dr. Guyer)
- “A Prospective, Randomized, Multicenter Food and Drug Administration Investigational Device Exemption Study of Lumbar Total Disc Replacement With the CHARITÉ™ Artificial Disc Versus Lumbar Fusion” posted in the Spine Journal (Drs. Guyer and Blumenthal)
- “Results of the Prospective, Randomized, Multicenter Food and Drug Administration Investigational Device Exemption Study of the ProDisc -L Total Disc Replacement Versus Circumferential Fusion for the Treatment of 1-Level Degenerative Disc Disease” posted in the Spine Journal (Dr. Zigler)
Frequently Asked Questions
As spinal structures degenerate, they may cause pain, limiting function and decreasing quality of life. Total disc replacement (TDR), also called artificial disc replacement (ADR), surgery is one of the latest advancements in spine surgery.
Replacing the disc removes the cause of pain while preserving natural motion. This surgery is recommended only after extensive conservative therapies have failed to significantly provide pain relief.
The advantages of disc replacement are the lessened changes at the levels above and below, which is what we call adjacent level disc disease, requiring surgery. This is one quarter to one-third less compared to fusion at 10 years.
In other words, if you have a fusion you have a 30 percent chance of having more surgery at a level above or below, whereas, if you have a disc replacement, it is 25% to one-third the rate as if you have had a fusion.
Patients with osteoporosis or fractured spines are generally not candidates. That consists of:
- Patients with low bone density
- Patients with a significant curve of the spine
- Patients with instability or too much motion of the spine with bending
Only after being evaluated by a surgeon can it be determined if TDR is a viable option for you.
Cervical Total Disc Replacement (TDR) is performed for the treatment of herniated disc, painful disc degeneration, radicular syndrome, and other cervical spine problems.
In the case of a cervical total disc replacement, the surgeon makes an incision in the front of the neck, and the contents of the neck are gently retracted, enabling the front part of the spine to be seen.
Cervical Disc Replacement is used to treat herniations that are pinching the nerves, giving the patient neck, shoulder, and arm pain.
This is probably the most common problem we see, particularly in younger individuals. As we get older; however, sometimes bones spurs can pinch the nerve passage and these too, depending on the size of the bone spur, are treatable by disc replacement.
Generally, it is done through a small incision that parallels the skin crease in the neck. It is not much longer than a 1-inch incision, and sometimes even smaller. Normally, you will feel some soreness in swallowing for a day or two, but the incisional pain quickly gets better because no major structures are cut other than the skin and a very thin muscle underneath the skin.
All the dissection is carried out by following normal tissue plains, in a fashion, we call blunt dissection. It is actually a very pretty operation for a surgeon to carry out because it is basically bloodless and we do not violate or injure the normal tissues.
After surgery, most patients usually experience relief of their arm symptoms and their neck pain as well. However, we know from all the FDA studies that the patients will quickly improve and will continue to do well for as long as we have been following them, and now up to ten years.
Right after surgery the patient will be placed in a soft collar and they are normally discharged within 23.5 hours, in some cases, it may be the same day, or may spend the day overnight. Generally, the soft collar is worn to protect the wound.
After the first visit at two weeks, the patient will start some general physical therapy. Because the disc replacement depends on the bone attaching to the prosthesis, the only restrictions we give the patient are to avoid hyperextension or looking up the ceiling and no impact loading such as running for the first 6 to 12 weeks, and certainly, we like the patient to lift no more than 10 pounds for the first 2 weeks.
After the disc is attached to the vertebral bodies, your doctor may release you to full activities, and in general, we wait for the 3-month mark before we allow people to go back to sporting activities. One can certainly carry on normal activities from the time they leave the hospital to the 3-month mark.
For a lumbar total disc replacement, an incision is made in the abdomen to expose the front part of the spine; the disc is approached after carefully separating away from the abdominal contents and major blood vessels are moved off to the side.
Fluoroscopy is used to determine the correct level(s) before the disc material is removed and the artificial disc is inserted. A cervical total disc replacement surgery takes approximately 1-2 hours; a lumbar total disc replacement surgery takes about 1-3 hours.
In preparation for having a lumbar disc replacement, a bone density scan will be obtained. This is a simple study, in which a non-radiation scanner counter passes over your body to record how much calcium is in your bones. You will undergo the normal pre-operative blood testing, so we can make certain there is no evidence of any infection.
At surgery, a small incision will be made up and down or to the side on the front of your lower belly. During the procedure, we do not go through the stomach, but rather we go inside the stomach wall pulling the sack that holds our organs over across the front of the spine. Many people think we go through the stomach and have to move all the organs. In fact, there are no muscles that are cut, and, again, we follow the normal tissue planes of the body.
Therefore, after the surgery is done and the surgeon removes the diseased disc and replaces a custom-made artificial disc in terms of size, height, and angle, most patients go home the day after surgery.
It is dependent on the return of bowel sounds. Sometimes the bowels do not begin to have their normal peristalsis or squeezing activity right after surgery and a patient may have to spend an extra day in the hospital.
In general, the patients are up and walking the same day as surgery and are often discharged the day after surgery. They wear a small corset for two weeks for wound healing, and then after that, they return to their doctor and begin physical therapy.
The only two restrictions they have are not to arch their back backward, or to jog, which causes impact loading and may disrupt the small micro connections between the bone and the prostheses.
At the end of the 3-months, the patient is released to full activities but can return to a non-laboring job in 2 weeks. In many ways, the recovery from an artificial disc is very similar to that of having a microdiscectomy, which is a little incision in the back of the spine to remove a soft disc herniation.
Artificial disc patients have a similar post-operative recovery in that the minimally invasive approach, which we call a retroperitoneal approach.
Primarily for those patients who have Degenerative Disc Disease, normally just a single level, for that is what the insurance companies that pay for this will cover. These patients must have and meet certain criteria and be eligible.
Some of the more basic ones are that one must have a normal bone density so that it can support the artificial disc. The little connecting joints or the facet joints must be normal, and there must not be a significant curvature of the spine.
One company did study two-level disc replacements, but chose, for economic reasons, not to go through the FDA to gain approval, but we do and carry out two- and in some cases, three-level disc replacement. This is considered to be “off-label” but still can be done with the consent of the patient and the physician.
The problem is, however, with insurance reimbursement. Insurances will, in general, only pay for a single level, if they pay for any.
Another good indication for lumbar disc replacement is for a patient who has had a recurrent herniated disc. In the past, these patients were recommended to have a fusion to prevent another herniation.
Now we have the ability to do a disc replacement that not only will remove the disc from the front, but also allow placement of the disc replacement and in essence giving them a normal disc.
Low back ADRs are typically used for low back pain, while neck artificial disc replacements are used for both neck and arm pain caused by a pinched nerve from a damaged disc.
Patients are generally not considered candidates for lumbar (low back) artificial disc replacement surgery unless they have failed to find relief from active therapy with or without injections and medications for a period of at least six months and are being considered and evaluated for a lumbar fusion.