Cervical Disc Prosthesis

Abstract

After World War II, the operation of a herniated disc of the cervical spine gradually developed into a routine procedure. In addition to a dorsal surgical approach, the ventral approach predominated, with fusion of the motion segments without or with disc replacement as a placeholder made of a wide variety of materials. In the lower segments of the cervical spine, the extent of physiological movements is less than in the upper half, but the lower half is more frequently affected by degenerative changes and free disc herniations. Fusion of a single motion segment leaves a restriction of mobility that is hardly noticeable to the patient. However, there is increasing evidence that, as a result of fusion over a period of months or years, mechanical overloading of the adjacent segments can lead to premature degeneration. Experimental pressure measurements in the adjacent intervertebral spaces after fusion have shown significantly increased values. However, the clinical sequelae are often only noticed after years or decades. To avoid the loss of mobility of a motion segment through disc surgery, disc prostheses were therefore developed, each of which was intended to maintain physiological mobility. Since about 2000, many models of cervical disc prostheses are now commercially available. Our own experiences within the framework of a prospective surgical study are presented.