Bryan cervical disc replacement，a five-year follow-up results

English Keywords:Cervical arthroplasty  Bryan disc prosthesis  Follow up  Outcome  MRI  Adjacent segment degeneration

English Abstract:

  【Abstract】 Objective：To investigate the five years′ follow-up outcomes of cervical arthroplasty with Bryan disc prosthesis.Method：70 patients have reached a postoperative period of 5 years since admission of this approach into our hospital in December 2003.57 patients obtained 57-69 months′（average，60 months） follow- up.There were 47 single-level，9 two-level and 1 three-level arthroplasties.The surgical levels included C3/4（5 cases），C4/5（10 cases），C5/6（45 cases） and C6/7（8 cases）.The clinical evaluation included mJOA，VAS and NDI score at pre-operation and final follow-up，Odom′s grading criteria at final follow-up.Radiographic evaluation included flexion/extension lateral view at operation level and heterotopic ossification around the prosthesis according to McAfee classification on lateral view X-ray.The adjacent segment degeneration was noted according to Miyazaki classification on MRI T2 weighted images.The invasion ratio of disc protrusion to the spinal canal at adjacent levels was recorded on mid-sagittal MRI T2 weighted images.Result：（1）The mJOA score was 13.4±1.9 of baseline and 16.1±1.1 at final follow-up.The improvement rate was 75.0%.The VAS for arm pain was 3.3±1.9 of baseline and 0.9±1.2 at final follow-up；the VAS for neck pain was 3.0±1.5 of baseline and 1.6±1.4 at final follow-up；the NDI score was 14.8±8.6 of baseline and 5.7±4.2 at final follow-up.All above-mentioned results showed statistical significance（P<0.05）.According to Odom′s criteria，there were 21 excellent，27 good，7 fair and 2 poor at final follow-up.（2）28 patients obtained X-ray follow-up：ROM at operation level was 6.9°±3.0° of baseline and 7.2°±3.7° at final follow-up，which showed no statistical significance（P>0.05）.The heterotopic ossification around the prosthesis was noted in 12 of 30（40%） segments，and 3（10%） segments lost movement at final follow-up.（3）25 patients gained MRI follow-up.7 of 50（14%） adjacent segments had nonsymptomatic disc degeneration to one grade.The invasion ratio of disc protrusion to the spinal canal at adjacent level increased 0.3%-0.5% every year.Conclusion：Cervical arthroplasty with Bryan disc prosthesis provides a favorable clinical and radiological outcome at an average of five years′ follow-up.The motion of operated level is well preserved.The prevalence of adjacent segment degeneration is low and no adjacent segment disease is noted.