Medium-term outcomes of artificial disc replacement for severe cervical disc narrowing

Objective: To determine if the Bryan cervical disc prosthesis could relieve objective neurological symptoms, signs, and restore mobility in patients with severe cervical disc narrowing. Methods: Clinical data of thirty-two patients underwent Bryan cervical disc replacement has been collected from April 2006 to February 2010. Severe cervical disc narrowing with grade V disc degeneration were included in this study. Bryan cervical disc prostheses have been implanted through anterior approach. Japanese Orthopedics Association (JOA) score, visual analog scale, Odom's scale, and flexion-extension radiological follow-ups were applied for evaluations. Results: A total of 41 Bryan disc prostheses from 32 patients with an average follow-up duration of 33.5 months (range 23 to 44 months) were evaluated. Clinical functions of patients were significantly improved. Preoperative averaged visual analog scale score of 6.3 +/- 2.2 was decreased to 1.3 +/- 1.2 (at 36 months, P<0.001), while preoperative averaged JOA score of 14.4 +/- 1.2 was increased to 16.3 +/- 0.9 (at 36 months, P<0.001). Thirty of 32 patients received excellent to good outcomes in Odom's scale. Averaged mobility was restored to (9.9 +/- 3.2)degrees at the last follow-up evaluation of 36 months. No subsidence or migration of implant was identified. Conclusions: Acceptable clinical outcome for treatment of severe cervical disc narrowing with cervical disc replacement technique has been performed in current study. Most patients maintained good postoperative mobility and no significant adjacent level degeneration were found. Cervical disc replacement may be applicable in treatment of severe cervical disc narrowing; however, longer follow-ups are required for ensuring the long-term efficacy of cervical disc replacement.