Total Disc Replacement

If neck discomfort becomes severe enough to interfere with daily activities or is accompanied by swelling, tenderness, or redness, it is crucial to seek medical help.

At Complete Orthopedics, our expert spine doctors specialize in treating cervical spine and neck pain with both surgical and non-surgical methods. We assess symptoms, determine the cause, and recommend the most appropriate treatments, including surgery if needed.

We serve the New York City and Long Island areas, collaborating with six hospitals to provide advanced cervical spine surgery and comprehensive orthopedic care. You can schedule a consultation with our orthopedic surgeons either online or by phone.

Learn about common causes of neck pain and the available treatment options, including when surgery might be the best solution.

Overview

Cervical Total Disc Replacement (CTDR) is a surgical procedure aimed at treating degenerative disc disease in the cervical spine, which can cause pain, numbness, and weakness due to the degeneration of the discs that act as cushions between the vertebrae. This innovative procedure involves replacing a damaged cervical disc with an artificial disc, which can help maintain normal motion in the neck, unlike traditional spinal fusion surgery that permanently connects vertebrae and restricts movement.

What is Degenerative Disc Disease?

Degenerative disc disease (DDD) occurs when the discs in the spine start to break down due to wear and tear. These discs act as shock absorbers between the vertebrae, allowing for flexibility and movement in the spine. Over time, these discs can lose their flexibility, elasticity, and shock-absorbing characteristics. When this degeneration happens in the cervical spine, it can lead to a variety of symptoms including neck pain, stiffness, and even neurological issues like numbness or weakness in the arms.

• 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.

Indications

CTDRs and LTDRs have different indications and can be used in young patients with various clinical signs. LTDRs are typically recommended for severe low back pain, while CTDRs are often performed alongside decompression surgery. Hybrid procedures, combining TDR with fusion, may be conducted in both cervical and lumbar regions.

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.

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.

Benefits of Cervical Total Disc Replacement

Maintained Mobility

One of the primary advantages of CTDR over spinal fusion is that it maintains motion at the operated level. Spinal fusion connects two or more vertebrae permanently, which restricts movement and can increase stress on the adjacent discs, potentially leading to further degeneration.

Reduced Risk of Adjacent Segment Disease

By preserving the natural motion of the spine, CTDR reduces the risk of degeneration in the discs adjacent to the treated segment, a common issue with spinal fusion. This is because spinal fusion alters the biomechanics of the spine, placing additional stress on the discs above and below the fusion.

Quicker Recovery

Patients often experience a quicker recovery time and less postoperative pain compared to those who undergo spinal fusion. This means they can return to their normal activities and work faster. Studies have shown that patients who undergo CTDR report less pain and better neck mobility post-surgery compared to those who have spinal fusion​

Potential Risks and Complications

As with any surgical procedure, CTDR comes with potential risks and complications:

• Infection: Any surgical procedure carries the risk of infection, though this is relatively rare with CTDR.
• Device Failure: Although uncommon, there is a risk that the artificial disc could fail, which might require further surgery.
• Nerve Damage: There’s a risk of nerve damage during the procedure, which can lead to symptoms such as pain, numbness, or weakness.
• Dysphagia: Some patients experience difficulty swallowing after the surgery, although this is typically temporary.

Who is a Candidate for Cervical Total Disc Replacement?

CTDR is not suitable for everyone. Ideal candidates are those who:

• Have one or two levels of cervical disc disease with associated radiculopathy or myelopathy.
• Do not have significant cervical spondylosis or facet joint disease.
• Are not significantly overweight, as obesity can increase the risk of complications.
• Do not have severe osteoporosis, which can affect bone integrity and the stability of the implant.

Candidates for CTDR should have tried and failed to find relief through non-surgical treatments such as physical therapy, medications, or injections. A thorough evaluation by a spine specialist is necessary to determine if CTDR is the appropriate treatment.

Postoperative Care and Rehabilitation

Postoperative care is crucial for the success of CTDR. After the surgery, patients are encouraged to:

Engage in Physical Therapy: Physical therapy is essential for regaining strength and flexibility in the neck and shoulder muscles. A physical therapist will guide the patient through exercises that help restore motion and reduce stiffness.

Avoid Strain: Patients should avoid activities that strain the neck, such as heavy lifting or repetitive neck movements, especially in the early stages of recovery. This helps ensure the artificial disc is not subjected to undue stress as it settles into place.

Follow-Up Visits: Regular follow-up visits with the surgeon are necessary to monitor the healing process and ensure the artificial disc is functioning correctly. These visits help identify and address any potential issues early on.

Long-Term Outlook

Most patients experience significant pain relief and improved neck function following CTDR. Long-term studies indicate that CTDR provides sustained benefits, including maintained motion at the treated segment and a reduced need for additional surgery compared to spinal fusion. The preservation of natural spinal motion is crucial for long-term spine health and overall quality of life​

Conclusion

Cervical Total Disc Replacement offers a promising alternative to traditional spinal fusion for treating degenerative disc disease in the cervical spine. By maintaining motion and potentially reducing the risk of adjacent segment disease, CTDR can lead to better long-term outcomes for patients. As with any medical procedure, it’s important for patients to discuss all options with their healthcare provider to determine the best treatment for their specific condition.

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