Cervical Prosthetics

Cervical disc herniation is the most frequent pathology in which a cervical prosthesis is implanted.

It can also be used on cervical discs in the early stages of osteoarthritic degeneration, where cervical nerves may be compressed by degenerative bone growths (osteophytes) that cause narrowing and compression of the nerve exit through the foramen.

Bryan's cervical prosthesis was the first to be implanted in 2001. After evaluating its efficacy in 54 patients in European hospitals, it emerged as an alternative treatment to cervical arthrodesis in herniated disc surgeries.

Since then, short, medium, and long-term studies have been carried out, and no complications of interest have been found in relation to prosthesis dislocation, loosening, infections, or other complications. Unlike knee or hip prostheses, reinterventions are not required to replace the prosthesis. This is due to the fact that its components do not suffer significant wear, as they do not have to withstand large loads or friction between materials.

A cervical prosthesis operation, for example for a cervical herniated disc, lasts around 75 minutes, in which general anesthesia is used and requires extensive experience in the surgeons who perform it.

Regarding surgery, it is performed through an anterolateral approach to the neck with an incision in the skinfold of about 3 cm. The tissues anterior to the sternocleidomastoid muscle are dissected and separated, directly reaching the anterior border of the spine. This is a very common and frequent approach in which complications usually do not arise.

Subsequently, a spacer is placed, the intervertebral disc is removed (discectomy), and the posterior herniated disc is removed. This is the fundamental step of the surgery and requires extensive experience. Thanks to the use of magnifying glasses with a light source or microscope, we ensure a complete release, removing all the hernia and possible bone excrescences (osteophytes) that may compress the nerve or spinal cord. After an abundant wash with physiological saline, the cervical prosthesis is implanted by means of radiological control. Finally, a suction net is placed, and the approach is closed in the different planes.

Cervical prosthesis or cervical arthroplasty is currently the best option for the treatment of cervical herniated disc since the herniated fragment is removed, the affected nerve root or spinal cord is decompressed, and the intervertebral disc is replaced by a device that performs the same functions like this, maintaining the mobility of that segment as in the natural vertebrae and the harmony of the global movement of the neck.

Traditionally, when myelopathy or compressive radiculopathy occurred due to a cervical disc herniation, the surgical treatment used was cervical arthrodesis.

This technique implies the loss of mobility of the arthrodesed level or levels, producing a decrease in the harmony of neck movement. Greater mobility is transferred to the levels immediately adjacent to the arthrodesed, so it is not uncommon that in a few years they can also be affected by ruptures of the fibrous ring due to hypermobility and cause herniated discs or osteoarthritic degeneration.

Likewise, the postoperative period of arthrodesis usually requires several days of hospitalization, unlike the mobile cervical prosthesis that allows the patient to go home 24 hours after the intervention. If a bone graft is used between the vertebrae, this leads to pain in the area and the risk of complications with the wound or nearby nerves. A collar is used for about 8 weeks, and alterations such as dysphagia (pain on swallowing) related to the rubbing of the plate against the esophagus are not uncommon. Another complication that can occur is pseudoarthrosis or lack of fusion of the vertebral bodies and the applied bone graft or implant, causing pain and requiring another surgery to achieve intervertebral fusion.

In case of any suspicion of hernia or cervical pathology that may be compressing a nerve or the spinal cord, we must carry out a study with the following complimentary tests:

• Lateral, anteroposterior, and functional X-ray in maximum extension and flexion of the cervical spine.
• Magnetic resonance (MRI).
• Neurophysiological study with electromyoneurogram

The patient must have maintained symptoms derived from the compression of the cervical disc herniation (myelopathy or radiculopathy) for at least 6 weeks without significant relief with anti-inflammatories, analgesics, or antineuritic drugs.

Sometimes, the pain is not bearable, and it becomes necessary to perform a cervical prosthesis surgery earlier.

Two or three days before surgery, it is advisable not to take anti-inflammatories and only maintain treatment with analgesics to avoid the antiplatelet effect. It is not essential, but we get less bleeding during the surgery and, therefore, less coagulation of the bleeding points.

Upon discharge from the hospital, a medical report is drawn up specifying the technique and the implanted mobile cervical prosthesis.

In relation to postsurgical medication, an analgesic drug is usually enough. Also, in the report, you can supplement anti-inflammatory and analgesic. Muscle relaxants are only recommended for cervical contracture.

The surgical wound is about 3 cm in the lateral part of the neck and over one of the cervical skinfolds. Only a few adhesive points are glued on the wound to avoid stressing the edges of the wound and maintain a linear scar. It is unusual for there to be complications of infection or openings of the wound due to its anatomical situation and the great vascularization of the area.

After the first 15 days, cervical physical activity can be increased, although it is advisable to perform neck movements from the first moment: flexion-extension, lateralization and rotation. Avoid bad posture or handling heavy loads in the first month.

If there is any cervical discomfort due to neck contracture, in relation to the surgical position, local heat can be applied 20 minutes 3-4 times a day and progressive stretching exercises can be performed to avoid contractures.

If residual cervical pain remains, the exercises can be complemented with a physical rehabilitation session, better in a specialized center.

Driving the car can be done as soon as there are no limitations in cervical mobility.

Recovery after an operation for a cervical herniated disc in which a cervical prosthesis has been implanted is very fast.

Only one night of hospitalization is required to maintain a drain until the next day to evacuate small bleeding caused by the cervical hernia operation.

The patient begins neck mobility immediately, without restrictions or significant pain. No neck brace is required, and daily activities can start progressively from the first day.

If there was a pain in the arm or leg before surgery, it is common to have some isolated cramp-like discomfort that is relieved in the first days after surgery. Sensitive alterations, such as tingling (paresthesia) or numbness (hypoesthesia), sometimes last for a few weeks and gradually disappear. This depends on the time and intensity of compression that the nerve or spinal cord has had before surgery.

The improvement in all scales of health, comfort and well-being is evidence of the mobile cervical prosthesis. The long-term results studied do not require long-term reviews or new surgeries for complications.

Some cervical prostheses can create anterior or posterior ossifications that limit their mobility over time. If that happens, it does not imply any clinical or functional alteration, so cervical prostheses do not have sequelae.

Our traumatologists specializing in neck pain and pathologies related to the spine at our Madrid medical center are pioneers in this series of operations, led by Dr. Elgeadi.