[Cervical Artificial Disc Replacement].

In Japan, cervical artificial disc replacement was approved by the Pharmaceuticals and Medical Devices Agency in December 2017, and two products, Mobi-C by Zimmer Biomet and Prestige LP by Medtronic, are on the market. Cervical artificial disc replacement preserves cervical motion; however, the device must be place carefully on the midline to take full advantage of its features. In addition, a reliable foraminotomy is required to cure or prevent radiculopathy due to residual foraminal stenosis. Artificial disc replacement(ADR) is now available for up to two consecutive intervertebral spaces, and it is now possible to combine ADR with anterior cervical discectomy(decompression) and fusion or anterior cervical discectomy as a hybrid procedure. Although the number of surgical options has increased, it may be difficult to choose a surgical method until further experience is gained. Even with cervical artificial disc replacement, age-related facet degeneration progresses reduce the range of motion, and cause adjacent segment disease. In addition, heterotopic ossification, a frequent complication of ADR, also causes a reduction in the range of motion; therefore, further investigation of its causes and improvements in equipment is needed.