Total Disc Replacement
Total disc replacement is a surgical procedure to replace and mimic the function of the natural intervertebral disc. The procedure is currently performed for diseased cervical or lumbar intervertebral disk. The artificial disk replacement has the advantage of maintaining the mobility of the involved segment as compared to fusion surgery.
The intervertebral disk is a tissue present between adjoining vertebrae of the spinal column. The disks have a soft gel-like inner nucleus pulpous and a tough outer ring called the annulus fibrosis. The normal intervertebral disk acts to cushion the forces experienced by vertebrae and prevent them from grinding against each other.
Axial section of the cervical spine showing disk herniation on MRI.
With advancing age, the water content of the nucleus pulposus may decrease, making it more susceptible to injuries. Repetitive activities such as bending, turning, twisting may cause tears in the annulus causing the bulging of the nucleus pulpous through the annulus.
The herniated disk may compress upon the nerves/spinal cord/dural sac to cause radiculopathy. Obesity, smoking, and improper posture while sitting or standing also make the disks more vulnerable to injuries resulting in prolapsed intervertebral disks (PIVD). Lifting weights and traumatic injuries frequently result in PIVD.
Total cervical disc replacement
The image above shows a total cervical disc replacement along with various parts of the cervical vertebra. The components of the total cervical disc replacement include metal parts attached on the adjoining vertebrae to create the space for the prosthetic disc. The prosthetic disc is usually made of a PEEK (poly-ether-ether-ketone) polymer.
The herniated disk is one of the leading causes of low back pain and radiating pain in the legs. Similarly, in the cervical spine, a prolapsed disk may cause neck pain and radiating pain in the arms. In severe cases, the herniation may result in weakness and numbness of the involved level.
Traditionally, surgical treatment for herniated disks has been done through the removal of the diseased disk and fusion of the adjoining vertebrae. The surgery is known to successfully alleviate the symptoms of the herniated disk in the neck or the lower back. However, due to the fusion of the vertebrae, the natural motion of the spine is lost in that segment.
Fusion surgery may therefore result in additional stress on the adjoining normal spine level. The additional stress may lead to increased wear and tear of various structures, known as degenerative spine disease. The loss of mobility is especially prominent in the neck, where patients may have limited motion while turning their heads.
Artificial disk replacement surgery prevents the complications of adjacent level degeneration and loss of movement. The total disk replacement surgery involves the removal of the diseased disk and bone spurs impinging on the nerves. The surgeon eases apart the vertebrae to create more space for the nerves.
The ends of the adjoining vertebrae are cleaned to prepare them for the disk insertion. The artificial disk is inserted in the natural space and the vertebral endplates hold the artificial disk in place. The position of the artificial disk is carefully inspected visually and with the help of an intraoperative X-ray.
Instruments used during a total cervical disc replacement
The instruments shown in the image above are used during the surgery to remove the diseased disc, create raw bone surface for implanting the metal endplates and subsequent insertion of the prosthetic disc.
Trial cervical disc replacement bearings
The trial cervical discs are used to find the correct size of the final cervical prosthetic disc for maximum stability and motion.
A rehabilitation period follows surgery and most patients are able to return back to their base activities in six weeks. The rehabilitation program focuses on strengthening the muscles of the neck or lower back after a period of healing.
Not all patients are candidates for an artificial disk replacement. Total disk replacement is indicated in the following patients:
- The intervertebral disk is the cause of symptoms as demonstrated by an MRI
- The symptoms result from the impingement of the involved nerve/spinal cord by the herniated disc.
- There has been a trial of conservative management in the form of therapy, NSAIDs, and heat/cold modalities.
- The symptoms have been present for more than 6 months.
- All other causes of symptoms have been ruled out.
A total disk replacement is contraindicated in patients suffering from osteoporosis, inflammatory spine diseases such as ankylosing spondylitis, rheumatoid arthritis, etc. The procedure is also contraindicated in patients with vertebral fractures, spine ligament injuries, or instability of the segment. Tumors, infections, and facet joint arthritis are also contraindications for performing total disk replacement.
A growing number of patients are undergoing cervical disc replacement or lumbar disc replacement. The procedure is successful to alleviate symptoms of radiculopathy from prolapsed intervertebral disk while maintaining spine biomechanics and motion.
Do you have more questions?
What materials are used in artificial discs?
Artificial discs are typically made from metal alloys such as titanium or cobalt-chromium and a medical-grade plastic called polyethylene. These materials are chosen for their strength, durability, and compatibility with the human body, ensuring they can withstand the stresses of daily activities
What are the chances of needing additional surgery after CTDR?
The likelihood of needing additional surgery is lower with CTDR compared to spinal fusion, especially concerning adjacent segment disease. However, some patients might still require further surgical interventions if complications arise or symptoms persist
Are there any activities I should avoid after CTDR?
Initially, you should avoid heavy lifting, repetitive neck movements, and high-impact activities. Your surgeon will provide specific guidelines based on your recovery progress. Gradually, you will be able to resume most activities as your neck heals
How does CTDR compare to spinal fusion in terms of pain relief?
Studies have shown that CTDR provides comparable, if not superior, pain relief compared to spinal fusion. Additionally, CTDR has the added benefit of preserving spinal motion, which can lead to better overall outcomes
Can CTDR be performed at multiple levels in the cervical spine?
Yes, CTDR can be performed at one or two levels in the cervical spine. Multi-level procedures are more complex and not suitable for all patients. A thorough evaluation is necessary to determine if you are a good candidate for multi-level CTDR
What are the long-term outcomes of CTDR?
Long-term studies show that CTDR provides sustained pain relief and functional improvement, maintaining motion at the treated segment. Patients typically experience a reduced need for additional surgery compared to those who undergo spinal fusion. This is due to the preservation of natural spinal motion, which helps to reduce stress on adjacent discs
Is CTDR suitable for elderly patients?
Age alone does not disqualify someone from CTDR. However, the overall health and bone quality of elderly patients must be considered. Conditions like osteoporosis might affect the stability of the implant. A comprehensive evaluation by a spine specialist will help determine if CTDR is appropriate
What is the success rate of CTDR?
The success rate of CTDR is high, with many studies reporting success rates of 80-90% in terms of pain relief and improved function. These rates are comparable to or better than those for spinal fusion, with the added benefit of motion preservation
Can CTDR be performed if I have osteoporosis?
Severe osteoporosis can affect bone integrity and stability of the implant, making CTDR less feasible. Each case needs to be evaluated individually, and other treatment options may be considered if osteoporosis is present
How does CTDR affect the range of motion in the neck?
CTDR aims to maintain the natural range of motion at the treated segment, unlike spinal fusion which restricts movement. This preservation of motion helps in maintaining overall spinal health and function
What are the signs of an artificial disc failing?
Signs of artificial disc failure include persistent or worsening pain, reduced range of motion, and symptoms of nerve compression such as numbness or weakness. Diagnostic imaging like X-rays or MRIs will be needed to confirm the failure
Can I drive after CTDR surgery?
You can typically resume driving once you are off pain medications and can comfortably and safely turn your head. This is usually within a few weeks post-surgery. However, it’s important to follow your surgeon’s specific advice on this matter
How does CTDR address nerve compression?
During CTDR, the damaged disc and any bone spurs that are pressing on the nerves are removed, which relieves pressure on the spinal cord and nerves. This alleviation of pressure helps reduce symptoms like pain, numbness, and weakness
Will I have a visible scar after CTDR?
The incision for CTDR is usually made in the front of the neck and is small, so any scar will typically be minimal and fade over time. Proper postoperative care and possibly scar treatment options can further reduce its visibility
What are the potential complications specific to CTDR?
Specific complications can include device dislocation, subsidence (sinking of the device into the vertebrae), and wear of the artificial disc. Although these complications are relatively rare, they can require additional surgical intervention if they occur
How soon after CTDR can I start exercising?
Light exercises and walking can usually be started within a few days after surgery. More vigorous activities should be introduced gradually and under the guidance of your physical therapist. This helps to ensure a safe and effective recovery
Can CTDR be performed on patients with previous spinal surgeries?
CTDR can be considered for patients with previous spinal surgeries, but each case needs to be evaluated individually. The previous surgery’s impact on the spine’s anatomy and stability will be crucial in determining feasibility and risks
How does CTDR affect overall spinal alignment?
CTDR aims to maintain or restore normal spinal alignment and curvature, potentially reducing the risk of further spinal issues
Are there non-surgical alternatives to CTDR for cervical disc disease?
Non-surgical treatments include physical therapy, medications, injections, and lifestyle modifications. Surgery is considered when these treatments fail to provide adequate relief
How do I choose the right surgeon for CTDR?
Look for a board-certified spine surgeon with extensive experience in performing CTDR. Check their credentials, patient reviews, and success rates with this specific procedure
What advancements are being made in CTDR technology?
Ongoing advancements include improved biomaterials, design enhancements for better motion preservation, and minimally invasive surgical techniques to reduce recovery time
My name is Dr. Suhirad Khokhar, and am an orthopaedic surgeon. I completed my MBBS (Bachelor of Medicine & Bachelor of Surgery) at Govt. Medical College, Patiala, India.
I specialize in musculoskeletal disorders and their management, and have personally approved of and written this content.
My profile page has all of my educational information, work experience, and all the pages on this site that I've contributed to.
