Menu Close

Artificial disk replacement is a newer surgical procedure for relieving spine pain. Similar to hip or knee joint replacements, a disk replacement substitutes a mechanical device for an intervertebral disk in the spine. The device is meant to restore motion to the spine by replacing the worn, degenerated disk. It is an alternative to the commonly performed anterior cervical discectomy and fusion (ACDF), a surgical procedure that is designed to address the pathology by eliminating motion at the diseased disc level. Artificial disk replacement initially gained FDA approval for use in the U.S. in 2004. Over the past several years, numerous other disk replacement designs have been developed and are currently being tested. Development of these procedures first appeared in the lumbar spine, and more recently cervical total disc replacements (cTDR) at one level, and now at two levels.

The natural cervical intervertebral disc is an amazing mechanical structure from an engineering perspective. It has the ability to absorb a large compressive load while still providing an impressive range of motion between the bones in the neck. Duplicating the natural disc’s form and function with a synthetic – or artificial – disc is challenging. However, several artificial cervical discs have been developed and are available as a surgical option for patients with symptomatic cervical disc problems.

One of the newer developments, Mobi-C is a cobalt chromium alloy and polyethylene mobile-bearing prosthesis specifically designed as a bone-sparing, cervical intervertebral disc replacement for both one and two-level indications. All other cervical disc prostheses are FDA approved for one-level use only. In addition to the unique mobile-bearing feature, Mobi-C offers a simplified surgical technique.

Although both ACDF and cTDR satisfactorily treat clinically symptomatic cervical pathology, fusion alters cervical mechanics by placing increased stresses on adjacent segments, which may contribute to the development of symptomatic degeneration at those adjacent levels. In comparison, at least in theory, by preserving the motion of the operated segment, cTDR places comparatively less stresses on adjacent levels, which may serve to protect those levels. Multilevel ACDF is biomechanically more demanding than single-level ACDF with concomitant greater stress distribution on adjacent levels. Additionally, reoperation rates are generally higher in multilevel versus single-level ACDF. Currently there is a paucity of medical evidence evaluating the outcome of multilevel cTDR procedures.

However this month there is a new published study. Five-year clinical results of cervical total disc replacement (cTDR) compared with anterior discectomy and fusion for treatment of two-level symptomatic degenerative disc disease: a prospective, randomized, controlled, multicenter investigational device exemption clinical trial has just been published by the Journal of Neurosurgery: Spine.

A total of 225 patients received the Mobi-C cervical total disc replacement device and 105 patients received ACDF. Both cervical total disc replacement and ACDF significantly improved general and disease-specific measures compared with baseline. However, there was significantly greater improvement in general and disease-specific outcome measures and a lower rate of reoperation in the 2-level disc replacement patients versus ACDF control patients.

In both groups, the overall rates of patient satisfaction were high. However, there was significantly higher reported patient satisfaction in the cTDR group versus the ACDF group. At 5 years, 96.4% of cTDR patients and 89.5% of ACDF patients reported being either very satisfied or somewhat satisfied with their treatment. At 5 years, 94.8% of patients in the cTDR group and 84.2% of patients in the ACDF group reported that they would definitely or probably recommend the surgery to a friend.