Total Disc Replacement

Cervical Total Disc Replacement (CTDR) is an advanced surgical procedure designed to treat degenerative disc disease in the cervical spine. Unlike traditional spinal fusion, which permanently restricts movement between vertebrae, CTDR maintains motion at the operated level, offering several benefits such as reduced pain, improved mobility, and a quicker recovery. This technique is particularly beneficial for patients suffering from neck pain, numbness, or weakness due to damaged cervical discs.

How Common It Is and Who Gets It? (Epidemiology)

Cervical degenerative disc disease (DDD) is a common condition, especially in individuals over the age of 40, with symptoms ranging from neck pain to severe neurological deficits like numbness or weakness in the arms. For those who fail conservative treatments such as physical therapy and medication, CTDR may be considered as an effective alternative to spinal fusion.

Why It Happens – Causes (Etiology and Pathophysiology)

Degenerative disc disease occurs when the discs between the vertebrae in the cervical spine deteriorate due to aging, wear, or trauma. This degeneration can lead to pain, stiffness, and compression of the spinal cord or nerve roots. Cervical spondylosis, a type of arthritis, and cervical radiculopathy, where nerves are compressed, are common conditions related to DDD. These conditions lead to symptoms like pain, tingling, or weakness in the neck, arms, or hands.

• Cervical spondylosis: This is a common age-related condition that involves the wear and tear of the spinal discs in the neck. As the discs dehydrate and shrink, signs of osteoarthritis, such as bone spurs, develop.
• Cervical radiculopathy: This occurs when a nerve in the neck is compressed or irritated where it branches away from the spinal cord, causing pain that radiates into the shoulder and arm, muscle weakness, and numbness.

History

Lumbar Total Disc Replacement (LTDR)

LTDR came before CTDR in historical context. In 1960, Fernstrom performed the initial implantation of the first LTDR, which took the shape of a steel ball. The procedure was conducted using an anterior approach.

At first, the outcomes appeared promising, but over time, it became evident that the ball settling into the subchondral bone led to disappointing long-term results. Schellnack and Buttner implanted the SB Charité® prosthesis in the early 1980s. This prosthesis comprised two chromium-cobalt plates and a mobile polyethylene core.

In France, David and Lemaire regularly used the three successive models [1–3] of this prosthesis. In 1989, Marnay described the ProDisc-L®, which featured plates with a central titanium stem. Following that time, numerous diverse LTDR designs have been introduced to the market.

Cervical Total Disc Replacement (CTDR)

In 1962, Fernstrom faced similar challenges with his prosthesis in CTDR (cervical total disc replacement) as he did with LTDR (lumbar total disc replacement). The Prestige® prosthesis, a metal-metal design screwed into the vertebral bodies with a stabilization crest, was not developed until 1989-1991. It was only in 1995 that Bryan started regularly utilizing the CTDR named after him. Under the supervision of Goffin and Pointillart, numerous multicenter studies followed the first implantation in Europe in 2000. Subsequently, a wide variety of CTDR designs have been introduced to the market.

Biomechanicals

Artificial disc replacements (TDRs) consist of bearing surfaces specifically engineered to endure load without fracturing, minimize friction and wear, and preserve the range of motion for as long as feasible. The assessment is based on wear and motion tests conducted under varying loads and movements. A lifespan of 30 to 50 years is deemed equivalent to the successful completion of 30 to 50 million cycles.
Materials:

• Metals and alloys, including:
  • stainless steel alloys,
  • titanium and titanium alloys
  • cobalt alloys
• Ceramics, known for their increased wear resistance but reduced ductility, tend to be more fragile in nature.
• For the nucleus positioned between the metal plates, high molecular weight polyethylene, such as UHMWPE (ultrahigh molecular weight
• polyethylene), is employed.

TDR models are categorized based on factors such as anchorage, surface and friction couple, constrained or unconstrained design, location of the center of movement, and compatibility with MRI scans.

The surface coating facilitates osseointegration and may be composed of materials such as hydroxyapatite, tricalcium phosphate, porous titanium, or chromium-cobalt.

Anchorage, referring to the contact between the implant and the vertebral plates, can be accomplished using a stem, screw, or macro-texture. In the case of constrained TDRs, stronger anchorage is necessary due to the higher transmission of forces to the vertebral plates. To safeguard the plates from potential mechanical stress, the Bryan CTDR incorporates highly mobile plates.

Friction Couples

• metal/polyethylene
• metal/metal
• ceramic/polyethylen
• ceramic/ceramic

Among the various friction bearings used in arthroplasty, the metal/polyethylene combination is the oldest and well-established, particularly in hip replacements. This combination serves as a reference point, but it is worth noting that the polyethylene debris particles produced in this setting are relatively large in size.

Metal-metal couples and, to an even greater extent, ceramic-ceramic couples generate minimal amounts of debris, which are also smaller in size. This characteristic greatly reduces the risk of inflammation associated with the presence of debris.

Lumbar

TDR is primarily indicated for chronic low back pain that does not respond to conservative treatment. Clinical assessment involves evaluating pain levels, functional impairment, and overall health. Factors associated with poor prognosis include prolonged symptom duration, severity of the condition, and psychological factors.

Radiographs and MRI help assess spinal alignment, disc pathology, and muscle degeneration. Vascular exploration and discography may be considered in certain cases. Previous discal surgery is a common indication, while conditions like malalignment and osteoporosis are contraindications for LTDR.

Cervical

The primary indication for CTDR is the presence of soft hernia leading to cervical radiculopathy or myelopathy that is resistant to treatment. The assessment process includes evaluating pain levels, functional impairment, and myelopathy scores. Surgical interventions for this condition may involve either discectomy or arthrodesis.

The suitability of CTDR for cases of osteophytic hard discal hernia and myelopathy caused by cervical osteoarthritis is a subject of ongoing debate. Certain factors serve as contraindications for CTDR, including prior cervical surgery, posterior joint osteoarthritis, ligament ossification, hyperostosis, instability, osteoporosis, and the presence of infectious or neoplastic conditions.

How the Body Part Normally Works? (Relevant Anatomy)

The cervical spine consists of seven vertebrae (C1 to C7), with intervertebral discs between each vertebra. These discs serve as cushions, allowing for movement and absorbing shock. Nerve roots exit the spinal cord through openings between the vertebrae. When these discs degenerate, they can press on the spinal cord or nerves, causing pain, numbness, and weakness.

What You Might Feel – Symptoms (Clinical Presentation)

Patients with cervical disc disease may experience:

• Neck Pain: Often radiates to the shoulders or arms.

• Numbness and Tingling: In the arms, hands, or fingers due to nerve compression.

• Muscle Weakness: Difficulty with grip strength or lifting objects.

• Loss of Balance: Due to cervical myelopathy affecting the spinal cord.

How Doctors Find the Problem? (Diagnosis and Imaging)

Diagnosis involves:

• X-rays: To assess the alignment and detect degenerative changes.

• MRI: Offers detailed images of the discs, spinal cord, and nerves.

• CT scans: Can provide more detailed images of bony structures and disc herniation.

• Electromyography (EMG): Used to assess nerve function and detect any abnormalities.

Classification

Cervical Total Disc Replacement is primarily indicated for patients with:

• Single or Multi-Level Cervical Disc Disease: Causing radiculopathy or myelopathy.

• Failure of Conservative Treatments: Patients who have not responded to non-surgical treatments like physical therapy or medications.

• Preservation of Motion: For those who desire to maintain the natural movement of the cervical spine.

Other Problems That Can Feel Similar (Differential Diagnosis)

Conditions that may mimic cervical disc disease include:

• Cervical Spondylosis: Arthritis in the neck causing pain and stiffness.

• Cervical Herniated Disc: Where the disc protrudes and presses on the spinal nerves.

• Facet Joint Osteoarthritis: Degenerative changes in the joints of the cervical spine.
  Accurate diagnosis through imaging studies is essential to differentiate these conditions and determine the best treatment.

Treatment Options

Non-Surgical Care: Physical therapy, medications (e.g., NSAIDs), and epidural steroid injections.

Surgical Care: For patients who don’t respond to conservative treatment, options include:

• • Cervical Total Disc Replacement (CTDR): Replaces a degenerated disc with an artificial disc to maintain spinal motion.

  • Spinal Fusion: When motion preservation is not a priority, fusion is used to stabilize the spine.

Surgical Techniques

Both LTDR and CTDR employ an anterior approach, albeit with distinct techniques. Anterior cervical disc procedures involve cervicotomy, leading to a lateral inclination of the trachea-bronchial axis. LTDR presents difficulties due to the close proximity of major blood vessels at specific lumbar levels.

LTDR

Throughout the procedure, the patient is positioned in the “French position” with legs apart and a bladder catheter inserted. The surgical field extends from the xyphoid region to the pubis, ensuring clear visibility of the iliac crests.

To minimize risks, the retroperitoneal approach is preferred over other options, reducing potential harm to the superior hypogastric plexus. Careful attention is given to controlling the median sacral vessels, and the disc is completely removed up to the dorsal longitudinal ligament.

Anchoring of the prosthesis is performed after thorough preparation of the vertebral plates, with precise centering being critical for optimal mechanical functioning.

The height of the LTDR varies depending on the specific level and the patient’s size. In some cases, oblique prostheses may be utilized to prevent undue traction on blood vessels. Vessel exposure can be challenging and may require the expertise of a skilled vascular surgeon. Although the lateral transpsoas approach is an alternative that avoids vessel dissection, it has not yet been fully validated.

CTDR

CTDR, much like LTDR, utilizes techniques similar to the implantation of an intersomatic cage. Before the procedure, careful planning is done, taking into account the dimensions of the disc and vertebral bodies.

During the surgery, the patient is positioned in dorsal decubitus with slight forward inclination, guided by fluoroscopy. Cervicotomy can be performed horizontally or vertically, depending on the number of levels involved. Discectomy includes the sectioning of the dorsal longitudinal ligament, and the use of an intersomatic distractor aids in exposing the discal space.

The specific resection techniques employed depend on the type of hernia. The height of the CTDR is determined by neighboring discs, taking into consideration factors such as postoperative neck pain and the preservation of range of motion. Postoperative recovery is usually uncomplicated, with no requirement for a cervical collar following CTDR.

TDR has proven to be as effective as fusion procedures. LTDR indications have diminished due to uncertain outcomes, except for specific cases like inflammatory single-discopathy. CTDR is a reasonable option for young patients with cervical disc herniation.

The procedure preserves preoperative range of motion and reduces involvement of adjacent segments. However, long-term follow-up is needed to confirm the advantages of TDR over fusion.

Recovery and What to Expect After Treatment

• Hospital Stay: Many patients undergoing CTDR are able to go home the same day or after a short stay.

• Pain Management: Postoperative pain is generally less than traditional fusion surgery and is managed with medications.

• Physical Therapy: Essential for regaining neck strength, flexibility, and movement.

• Activity Restrictions: Patients are advised to avoid heavy lifting and strenuous activities during the early stages of recovery.

Most patients return to normal activities within a few weeks to months, depending on their individual recovery process.

Possible Risks or Side Effects (Complications)

Like any surgical procedure, CTDR comes with potential risks, including:

• Infection: Risk at the surgical site, though relatively rare.

• Nerve Damage: There’s a small risk of nerve injury during the procedure.

• Device Failure: The artificial disc may fail or become dislodged.

• Dysphagia: Difficulty swallowing, which is usually temporary.

• Adjacent Segment Disease: There is still a risk of degeneration in the discs above or below the treated segment over time, although this risk is lower compared to spinal fusion.

Long-Term Outlook (Prognosis)

CTDR provides long-term relief for many patients, with studies showing improved neck mobility and reduced pain compared to spinal fusion. The preservation of spinal motion reduces the risk of degeneration in adjacent discs and enhances overall spinal health. However, long-term follow-up is important to monitor the artificial disc and ensure it remains stable.

Out-of-Pocket Costs

Medicare

CPT Code 22856 – Cervical Total Disc Replacement (CTDR): $396.11
CPT Code 22551 – Spinal Fusion (Cervical): $417.50

Under Medicare, 80% of the approved amount for these procedures is covered once the annual deductible has been met. The remaining 20% is typically the patient’s responsibility. Supplemental insurance plans—such as Medigap, AARP, or Blue Cross Blue Shield—usually cover this 20%, leaving most patients with little to no out-of-pocket expenses for Medicare-approved cervical surgeries like CTDR and spinal fusion. These supplemental plans work directly with Medicare to provide comprehensive coverage for advanced spinal procedures.

If you have secondary insurance—such as Employer-Based coverage, TRICARE, or Veterans Health Administration (VHA)—it acts as a secondary payer once Medicare has processed the claim. After your deductible is satisfied, the secondary plan may cover any remaining balance, including coinsurance or small residual charges. Secondary plans typically have a modest deductible, ranging from $100 to $300, depending on the policy and network status.

Workers’ Compensation
If your cervical spine condition requiring CTDR or fusion surgery is work-related, Workers’ Compensation will fully cover all related surgical and hospital expenses. You will have no out-of-pocket expenses under an accepted Workers’ Compensation claim.

No-Fault Insurance
If your cervical spine injury requiring surgery resulted from a motor vehicle accident, No-Fault Insurance will cover all necessary medical and surgical costs, including CTDR and fusion. The only potential out-of-pocket cost may be a small deductible depending on your specific policy terms.

Example
Sally, a 58-year-old patient with cervical disc degeneration, underwent cervical total disc replacement (CPT 22856) and cervical spinal fusion (CPT 22551) to stabilize her neck and relieve pain. Her estimated Medicare out-of-pocket costs were $396.11 and $417.50, respectively. Since she had supplemental insurance through Blue Cross Blue Shield, the 20% that Medicare did not cover was fully paid, leaving her with no out-of-pocket expenses for the surgery.

Frequently Asked Questions (FAQ)

Q. How does CTDR compare to spinal fusion?
A. CTDR preserves motion at the treated level, which is a significant advantage over spinal fusion that restricts movement. This leads to better long-term spine health and reduces the risk of adjacent segment degeneration.

Q. Will I need physical therapy after surgery?
A. Yes, physical therapy is crucial for regaining strength and flexibility in the neck and for reducing stiffness following the surgery.

Summary and Takeaway

Cervical Total Disc Replacement (CTDR) offers an effective solution for patients with degenerative disc disease in the cervical spine. By maintaining motion and reducing the risk of adjacent segment degeneration, CTDR provides long-term benefits over traditional spinal fusion. With proper selection and post-operative care, patients can experience significant pain relief and improved function.

Clinical Insight & Recent Findings

A recent study examined the postoperative outcomes of a multimodal physical therapy (PT) program following Cervical Total Disc Replacement (CTDR) in a 37-year-old Brazilian Jiu-Jitsu athlete. The patient, who had undergone CTDR for C5-C6 and C6-C7 herniated discs, showed significant improvements in pain, function, and quality of life.

After 14 sessions spanning 16 weeks, the patient reported a complete recovery in pain, function, and ability to perform activities, including returning to full-contact sports like BJJ. The PT program was tailored to the healing process, emphasizing manual therapy, therapeutic exercises, and sport-specific rehabilitation.

The case highlights the importance of a personalized, structured PT regimen for achieving optimal outcomes post-CTDR. (“Study of postoperative physical therapy following CTDR – See PubMed.“)

Who Performs This Treatment? (Specialists and Team Involved)

CTDR is typically performed by orthopedic spine surgeons or neurosurgeons with specialized training in cervical spine surgeries. The procedure is supported by a multidisciplinary team, including anesthesiologists, nurses, and rehabilitation specialists.

When to See a Specialist?

If you are experiencing chronic neck pain, numbness, tingling, or weakness in the arms, a spine specialist can help assess whether CTDR is the right treatment option for your condition.

When to Go to the Emergency Room?

Seek emergency care if you experience sudden weakness, difficulty breathing, or loss of bowel or bladder control, as these could be signs of a spinal emergency requiring immediate attention.

What Recovery Really Looks Like?

Most patients undergoing CTDR experience a faster recovery compared to spinal fusion, with many returning to their normal activities within a few weeks. Rehabilitation through physical therapy is essential to regain full strength and mobility.

What Happens If You Ignore It?

Ignoring cervical disc disease can lead to worsening symptoms, including permanent nerve damage, loss of function, and disability. Early intervention with CTDR can prevent these outcomes and improve long-term quality of life.

How to Prevent It?

Maintaining good posture, regular neck-strengthening exercises, and proper ergonomics can help prevent or slow the progression of cervical disc degeneration. Regular check-ups with a spine specialist can help detect early signs of cervical issues.

Nutrition and Bone or Joint Health

Proper nutrition, including adequate calcium and vitamin D intake, supports bone health and may help prevent degenerative disc disease. Strong bones and joints contribute to overall spine health and may reduce the risk of requiring surgical intervention.

Activity and Lifestyle Modifications

After surgery, patients should avoid heavy lifting and high-impact activities to ensure proper healing. Gentle exercises and physical therapy are recommended to improve mobility and strength while safeguarding the spine.

Do you have more questions?