BACKGROUND
Anterior cervical discectomy and fusion (ACDF) is a well-accepted procedure for the treatment of cervical radiculopathy. Hilibrand et al. reported that adjacent segment disease is known to occur at a rate of 2.9% per year after cervical fusion. Developers of cervical disc replacements postulate that maintaining more normal motion may reduce the rate of adjacent segment disease. The purpose of this study was to compare the 2-year efficacy and safety of ACDF and cervical total disc replacement surgery.

METHODS
Eighty-seven patients from 2 sites of this 13 multicenter trial were randomized to treatment with either ACDF or cervical disc replacement surgery with the ProDisc-C (Synthes, Inc., West Chester, Pennsylvania) implant. Patient outcomes were assessed via neck disability index (NDI), visual analog pain scale (VAS), and health survey SF-36 (QualityMetric, Lincoln, Rhode Island). Forty-four patients were treated with ACDF using allograft and plating, and 43 were treated with cervical disc replacement. The average age was 44 (23 to 61) years. All surgical procedures were single level.

Errata for this issue

RESULTS
At all measured time points, both groups showed statistically significant improvement over their preoperative baseline with regard to NDI, VAS arm and neck pain levels, SF-36 mental composite score (MCS), and physical composite score (PCS) (P < .05). At 24 months, the disc replacement group showed results equivalent to the ACDF group with regard to NDI, VAS arm and neck pain, and SF-36 MCS. At 24 months, the disc replacement group showed significantly greater improvement in SF-36 PCS as compared to the ACDF group (P = .0359). Of note, there was a trend toward greater patient satisfaction in the disc replacement group as compared to the ACDF group (83% versus 71%, P = .144).

CONCLUSIONS
This study indicates that the tested disc replacement device achieves 2-year results ranging from equivalent to superior in comparison to ACDF in the treatment of symptomatic cervical disc disease. Long-term maintenance of these results has not yet been determined.

Key Words Anterior cervical discectomy and fusion, cervical total disc replacement. SAS Journal. Spring 2008. 2:76–85. DOI: SASJ-2007-0124-RR

^aOrthoCarolina, Charlotte, North Carolina; ^bSpine Education and Research Institute, Thornton, Colorado; ^cOrthoCarolina Research Institute, Charlotte, North Carolina

Michael Jannsen, MD, has received clinical research support from Synthes Spine and has a consulting agreement with Synthes Spine. Daniel Murrey, MD, and Bruce Darden, MD, are consultants to Synthes Spine and Stryker Spine and received research support from Synthes. Bruce Darden, MD, also owns stock in Synthes.
This study is a cohort of an FDA IDE trial supported by Synthes.

Institutional Review Board approval was obtained from Presbyterian Healthcare.

Address correspondence to Daniel B. Murrey, MD, OrthoCarolina, 2001 Randolph Road, Charlotte, NC 28207.

This manuscript was submitted December 4, 2007, and accepted for publication April 24, 2008.