Kineflex|C® Cervical Artificial Disc Implant

Introduction
Degenerative Disc Disease (DDD) is a disorder of the spine characterized by a narrowing of the disc space between two vertebrae where the disc resides. By age 50, more than half of the U.S. population has evidence of disc degeneration.

As the disc ages it becomes brittle, dehydrated, and less flexible, and it loses height as well as the ability to act as a cushion or shock absorber for the spine. In addition, the disc may bulge outward, compressing nerve roots and causing arm pain.

Mechanical dysfunction may also cause disc degeneration and pain. A disc may be damaged as the result of trauma that overloads the capacity of the disc to withstand the forces passing through it, and annular fibers may tear. These torn fibers may be the focus for an inflammatory response and may cause pain.

The cervical column is made up of many joints which allow the body to bend, twist and move. Pain often results when there is something wrong with these joints. Currently, fusion surgery is the standard treatment for someone who has degenerative disc disease of the cervical spine. With symptomatic cervical disc disease, a spine surgeon may need to remove the disc, which is between the vertebrae bones, and fuse the two bones together. This fusion often relieves the symptoms of pain, but makes the joint incapable of normal movement.

Artificial discs such as the Kineflex|C have been proposed to offer potential improvements in function while also relieving pain. This study is designed to assess the ability of the Kineflex|C device to relieve the symptoms associated with cervical disc disease. The goal of the Kineflex|C artificial disc is to preserve motion, while minimizing or eliminating pain due to cervical disc disease.

Although this is a fairly new procedure in the United States, artificial discs have been used in Europe and South Africa for many years. The Kineflex|C has been implanted in more than 250 patients in South Africa.

Study objectives
The researchers are evaluating the Kineflex|C artificial disc for the treatment of cervical DDD. The physicians will be comparing the safety and effectiveness of the Kineflex|C artificial disc to anterior cervical discectomy and fusion surgery.

Study overview
This is a multi-center, prospective, randomized, controlled clinical trial assessing the safety and effectiveness of the Kineflex|C to relieve the symptoms associated with DDD in the cervical spine. The purpose of the study is to compare the effectiveness of disc replacement surgery for the treatment of discogenic pain at one cervical level (from C3 to C7) performed using the Kineflex|C to anterior fusion surgery. Up to three hundred and twenty-eight (328) patients will participate in the study at up to 20 medical centers.

Patients who qualify for the study will be placed into one of two groups: (1) treatment with the investigational artificial disc (the Kineflex|C) or (2) treatment with anterior fusion surgery. This is a random selection, like the toss of a coin.

Following surgery, patients should expect to experience some pain related to the surgical site. Pain medication will be available to take as directed by the physician. Initially there may be some limits placed on physical activities, although physical therapy will be prescribed.

All patients will need to be evaluated at regular follow-up visits. There will be one visit post operatively, 6 weeks after surgery, and then other visits at 3, 6, 12, and 24 months. During these visits, one or more medical professionals will evaluate each patient’s physical condition. It is important to know and understand that enrollment in this study requires that each patient complete all follow-up visits in a timely manner. This is an agreement that each patient will make with the physician and the sponsor of the study. Without the follow-up, the patient could invalidate the study and prevent or lengthen the approval process.

The risks are the same as those associated with other surgery and general anesthesia. Some of the risks include bleeding, infection, or sensitivity to the prosthetic material. This is not a complete list of all potential side effects. The physician conducting this clinical trail will have a detailed discussion with the patient and family prior to enrollment in the study. During that discussion, patients and family members are encouraged to ask questions to gain a better understanding of all of the risks and potential benefits.

Status
Recruiting

Inclusion criteria overview
Patients must meet the following criteria to be enrolled in this study:

• Be between 18 and 60 years of age;
• Have degenerated/dark disc at only one cervical level from C3 to C7 on MR (disc height decreased by ≥1 mm when compared to adjacent levels on radiographic film, CT, or MRI OR disc herniation on CT or MRI);
• Have symptoms of radiculopathy  in neck, one or both shoulders and/or one or both arms;
• Have at least six months of prior conservative treatment, the presence of progressive symptoms or signs of nerve root compression;
• Have a Neck Disability Index (NDI) demonstrating moderate disability.

Exclusion criteria overview
Patients who meet any of the following criteria are excluded from participating in this study:

• Marked cervical instability;
• Non discogenic neck pain or non discogenic source of symptoms;
• Severe facet disease or facet degeneration;
• Bridging osteophytes;
• Less than 2 degrees of motion at index level;
• Prior surgery at the level to be treated, except laminotomy without accompanying facetotomy;
• Prior fusion at any cervical level;
• More than one neck surgery via anterior approach;
• Previous trauma to the C3-C7 levels with compression or bursting;
• Documented presence of free nuclear fragment at any cervical level;
• Severe myelopathy;
• Any paralysis;
• Recent history (within previous six months) of chemical or alcohol dependence;
• Active systemic infection or infection at the site of surgery;
• Prior disc space infection or osteomyelitis in the cervical spine;
• Any terminal, systemic or autoimmune disease;
• Metabolic bone disease (e.g., osteoporosis, gout, osteomalacia, Paget’s disease);
• Any disease, condition or surgery which might impair healing
• Current or extended use (> 6 months) of any drug known to interfere with bone or soft tissue healing;
• Known metal allergy;
• Arachnoiditis;
• Currently experiencing an episode of major mental illness, or manifesting physical symptoms without a diagnosable medical condition to account for the symptoms, which may indicate symptoms of psychological rather than physical origin;
• Pregnancy at time of enrollment, or planning to become pregnant, since this would contraindicate surgery;
• Use of spinal stimulator prior to surgery.

Caution:
Investigational Device, limited by United States Law to Investigational Use