hat is Cervical Disc Replacement?

Cervical disc replacement is a minimally invasive surgical option that uses implants and other hardware to create a stable spine structure. This surgery provides relief by removing damaged intervertebral discs in patients with diseases of the cervical spine, such as disc degeneration and spinal stenosis. The procedure is considered minimally invasive because the surgery is completed through a small incision and by pushing aside muscle tissue rather than by opening the entire back and cutting through muscle tissue as in traditional back surgery.

Related Symptoms

Symptoms of cervical spine disease can manifest as localized and/or radiating symptoms. Localized symptoms include neck pain, neck stiffness, decreased range of motion, and cracking sounds in the neck with motion. Headaches are also common; they usually start in the neck and radiate up to the back of the head, but can radiate to the front of the head as well.  Radiating symptoms typically occur unilaterally (on one side of the body), but can occur on both sides and will generally follow the nerves in the neck, branching into the shoulders, arms, and hands. Radiating pain can be described as sharp, shooting, throbbing, electrical, burning, numbness, or tingling and there may be weakness with specific muscle actions.

Related Diseases

Cervical Disc Herniation: Intervertebral discs provide shock absorption in the spine and are made of a fibrous outer ring, the annulus fibrosis, surrounding a jelly-like inner section, the nucleus pulposus. As repetitive tasks and aging create wear on the annulus fibrosis, small tears create weak spots in the disc and the nucleus pulposus squeezes through, creating a herniated disc and potentially compressing the spinal cord and/or nerve roots.

Cervical Spinal Stenosis: Spinal stenosis is narrowing of the spine around neural elements, like the spinal cord and nerve roots. Narrowing may occur from a variety of causes, including disc herniation or arthritis. Arthritis and aging can cause intervertebral discs to shrink, narrowing the space through which nerves branch out from the spine; they can initiate bone spur formation, which are bony growths meant to prevent movement at a joint, but can compress a nerve; and they can cause ligaments to grow, which can also compress a nerve.

Cervical Pinched Nerves: Pinched nerves include the spinal nerve roots that are being compressed because of diseases, such as disc herniation or spinal stenosis.

Cervical Facet Joint Syndrome: The facet joints connect spinal vertebrae, enabling motion in the spine while also preventing extreme motions. As wear accumulates, the surrounding cartilage begins to thin and the lubricating synovial fluid runs low, allowing bone on bone grinding. To prevent motion at these areas of friction, the spine starts forming bone spurs, or bony growths, that may press on a nerve directly or cause inflammation of the joint.

Most cervical spine disease is initially treated with conservative options. Common treatments include, rest, lifestyle modification, physical therapy, massage, chiropractic care, home exercises, medications and steroid injections. Treatments may be used in any number or combination, but surgical options, such as cervical disc replacement surgery, are considered if the conservative options do not bring relief.

Rest

Rest in the context of treatment means avoiding activities that put stress on the neck, such as lifting weights or maintain poor posture at a desk. This is generally prescribed for a duration ranging from a shorter duration of several days up to several weeks. It is important to support the neck with certain pillows, sitting with support, or laying down. Rest may also include heat therapy with hot showers or heating pads and cold therapy with ice.

Lifestyle Modifications

Certain lifestyle factors may increase the incidence of a cervical spine disease, such as smoking and increased weight. Smoking decreases blood flow throughout the body which is needed to repair damaged tissues, including those around a compressed nerve. Cessation may restore blood flow, allowing the tissues to access proper nutrition. Added weight may increase the risk for disc herniation which may pinch the nerve, or the acceleration of the aging process, leading to pinched nerves. Reducing weight through a low-calorie diet and exercise can reduce pressure on the spine, decreasing the symptoms of cervical spine disease.

Repetitive leisure or work-related motions such as excessive bending, lifting, and twisting, along with any activity that may be high impact on the spine, such as running or riding ATVs, can also lead to cervical spine disease. Some of these repetitive task activities may be due to leisure and others due to demands of a job. For people with full labor or heavy-duty jobs, you may need to change jobs or support your work with proper lifting technique, relaxed breaks, and equipment such as a back brace to avoid worsening symptoms. You may also need to alter or avoid high impact activities, such as running to reduce the symptoms of cervical spine disease.

Physical Therapy

Physical therapy focuses on changing body mechanics to improve posture and walking as well as to strengthen and retrain muscles, particularly those in the core. The initial step is meeting with a Physical Therapist for a consultation to assess posture, gait, and muscle weakness and to design a personalized exercise program. Other techniques that physical therapists may use are manual treatments such as massage, ultrasound, and electro-stimulation through a TENS (transcutaneous electrical nerve stimulation) unit. A combination of these methods can provide symptom relief.

Alternative Therapy

Alternative therapies include massages, chiropractic care, and acupuncture. These may also be referred to as manual therapies since they address the spine with hands on technique. Massage relieves tension in muscles surrounding the spine and in arm and leg muscles experiencing radiating symptoms. These muscles may be under tension due abnormalities with walking and changes in posture due to pain from cervical spine disease. Chiropractic care may use specific techniques, such as adjusting the spine or application of traction on the spine. Acupuncture may also provide pain relief as muscles are stimulated electrically.

Home Exercises

A home exercise program may be used in conjunction with or instead of a formal physical therapy regimen. A daily low impact exercise regimen is important for strengthening muscles, especially those in the core. Low impact cardiovascular activities such as walking, swimming, elliptical, and biking are also important for increasing blood flow and strengthening muscles without adding stress on the spine. Home exercise can also lead to weight loss which may reduce pressure on the spine and reduce symptoms. Home exercise routines should be paired with stretches and physician supervision to avoid harm.

Medications

There are multiple types of prescribed and over the counter medications that may be used to treat the symptoms of cervical spine disease. Some of these medications include Tylenol (acetaminophen), NSAIDs (nonsteroidal anti-inflammatory drugs), muscle relaxants, nerve membrane stabilizers, topical medications, and off label medications.

Common over the counter medications are acetaminophen and NSAIDs. Acetaminophen is considered an analgesic, meaning it relieves pain but does not reduce inflammation. NSAIDs are effective at both relieving pain and reducing inflammation; they can be found in brand and generic forms over the counter. These medications are best taken with food to avoid an upset stomach. They can be taken for longer durations, as long as there is no history of kidney disease. The mechanism of both NSAIDs and Acetaminophen differ, so they are taken together often to combat pain.

Topical medications may also relieve pain and are available in over the counter and prescription variations. Common over the counter formulations are Salonpas, Icy Hot, Bengay, and Aspercream, which bring localized pain relief to the location where they are applied. Prescription topical medications also provide localized relief and include lidocaine, a numbing medication, and Diclofenac (Voltaren), an anti-inflammatory medication. Topical medications are good options for those that want to avoid or are unable to take oral medications.

Muscle relaxants are used to provide relief from muscle spasms and increase range of motion; they are best used in combination with physical therapy or an exercise/stretching regimen. Drowsiness is a common side effect of muscle relaxants and they are not recommended while driving or working. Common muscle relaxants include Flexeril, Soma, Baclofen, Robaxin, and Tizanidine.

Nerve membrane stabilizers are another class of medications often used to treat the numbness, tingling, shooting, stabbing, or radiating pain associated with cervical spine disease. Gabapentin (Neurontin) and Lyrica (Pregabalin) are commonly prescribed nerve membrane stabilizers and work by reducing pain signals released by nerves. Both medications, Gabapentin especially, can be taken in higher dosages multiple times per day, but this class of medication may cause dizziness and drowsiness. Nerve membrane stabilizers are typically started on a low and infrequent dose; the dosage is gradually increased until the pain is controlled and then gradually decreased prior to discontinuation.

There are other medications that may be used ‘off-label,’ meaning not for the use listed on the label. Some common medications used off label for pain are anti-depressants, such as Cymbalta and Amitriptyline. Similar to the nerve membrane stabilizers, these medications are slowly increased in dosage and they also target nerve-type pain, such as burning, numbness, and tingling associated with nerve pain. They may also cause drowsiness and are usually used at night for pain control.

Epidural Steroid Injections

Epidural steroid injections reduce pain by injecting steroid, or anti-inflammatory, medication at a specific level/levels in the spine. As the herniation places pressure on a nerve, this causes inflammation of the nerve and surrounding tissue which causes pain. A specialized needle is used to deliver medication to the correct area, past the muscles of the back and as close to the spinal nerves as possible. As steroids are a natural anti-inflammatory, this may reduce the inflammation around the nerve, diminishing pain caused by the disc herniation. Steroid injections have the ability to provide pain relief for up to several months, and provide better pain relief for radiating symptoms, such as leg pain, than treatments designed for back pain alone. Steroid injections are only safe to have completed 3 times in one year and must be at least one month apart between sequential injections. This is due to the muscle and tendon breakdown with exposure to the steroid medication too often or too soon.

Preparation for spine surgery begins with a patient history, physical exam, and imaging to confirm the spinal disease diagnosis, to determine the affected level, and to decide on the type of surgery. Cervical disc replacement is a minimally invasive stabilization procedure used to treat refractory spine disease symptoms in the cervical region.

The cervical disc replacement is performed with the patient laying on his or her back. An intraoperative x-ray machine is used throughout the procedure to confirm that the correct vertebra/vertebrae are being operated on. After locating the proper vertebra, the skin is marked, cleaned, and draped for sterility. A small incision, less than one inch, is made and the muscles on the front of the neck are gently parted. While working to part through the muscles, the vessels of the neck, including the carotid artery and jugular veins are carefully moved out of the surgical field.

Once the spine is exposed specialized retractors keep the incision open for the duration of the procedure, allowing the surgeon to see and operate. The anterior longitudinal ligament, a large ligament that runs along the spinal vertebrae, is removed to reveal the disc space between the affected vertebrae. The intervertebral disc is removed from this space via a series of biting instruments, until nothing occupies the disc space. After the disc is removed, the spinal cord and nerve roots are visible; compressing disc herniation or bone spurs can be removed to relieve pressure on the nerves and/or spinal cord.

The disc space is drilled to provide a smoother surface, measured to select an implant that will fit in the space, and then the correct size implant is placed into the empty disc space. The implant fit and spinal alignment are confirmed with intraoperative imaging. After placing the hardware, the retractors are removed from the incision and bleeding is controlled. Each layer of tissue is closed with sutures and the final layer of skin is usually closed with a special medical grade glue, which typically leaves less scaring after healing; the final layer may be fully closed with sutures depending on the surgeon’s preference and on the patient’s skin.

After surgery the patient recovers in a post-operative room to make sure that their pain is under control, that they are able to eat and tolerate food and beverage, and that they can walk and urinate properly. They are able to go home within 23 hours of the procedure, but a friend or family member should be available to drive the patient home and to monitor the patient for at least 24 hours after the procedure.

Post-Operative Recovery

This procedure is minimally invasive, allowing the patient to get discharged and head home within 24 hours of surgery. There are post-operative instructions to follow the six weeks after surgery to protect the spine and hardware and to ensure a full recovery.

Elevate head of bed: For at least the first week, sleep with the head of bed elevated to a minimum of 30 degrees or sleep in a recliner. The elevation may reduce swelling in the neck due to the natural inflammation process triggered by surgery, easing post-operative pain and making it easier to swallow.

Activity Restriction: Avoid high impact activities, heavy lifting, and repetitive tasks that require range of motion in the neck for at least the first three weeks after surgery. This may include driving because checking the blind spot requires turning the head.

Cervical Collar: Some patients may be placed in a soft, foam collar or in a rigid collar at the surgeon’s discretion. Generally, the collar is worn, except for at night over the first three weeks. A cervical collar should not be worn while driving as it prevents motion in the neck and would not allow for checking the blind spot before switching lanes or turning.

Walking: Walking increases blood flow, reduces the likelihood of blood clots, and reduces the likelihood of pneumonia during post-operative recovery.

Proper Nutrition: Proper intake of protein and vitamins (specifically Vitamin A) in the diet is important for healing wounds and tissues after a surgical procedure.

Pain Medication: Take prescribed pain medication only as directed and as long as necessary. Most patients are able to stop taking their prescribed pain medication within one week of surgery. Over the counter medications, such as Acetaminophen (Tylenol) and non-steroidal anti-inflammatory drugs (e.g. Ibuprofen) may be used as a supplement to or instead of prescribed pain medication.

Six Weeks After Surgery

Patients are typically evaluated with x-ray imaging to check on the placement of hardware and the recovery of the incision site for routine healing. If a cervical collar was required, it no longer needs to be worn except if needed for comfort. The majority of patients will return to work one to two weeks after the procedure, but patients that work physically demanding and labor type jobs should take more time away from work. At six weeks, all patients are able to return to work. Most patients no longer use any prescribed pain medication at six weeks, but may be using over the counter medications as needed. High impact activities, such as running, bungee jumping, downhill skiing/snowboarding, or heavy weight lifting, are still discouraged.

Twelve Months After Surgery

Patients typically undergo x-ray imaging again to get flexion (chin to chest) and extension (head tilted back) views of the cervical spine. These check spinal range of motion and confirm that there is no vertebral sliding because of the implant. All patients are back to work and performing a normal routine. The incision is well healed.