Sagittal alignment comparison of Bryan disc arthroplasty with ProDisc-C arthroplasty: a prospective, randomized controlled clinical trial.

STUDY DESIGN

A prospective, randomized study of the radiographic outcomes in patients undergoing single-level cervical arthroplasty with Bryan disc and ProDisc-C prosthesis.

OBJECTIVE

The purpose of this trial was to compare the alignment changes of Bryan disc arthroplasty (modified techniques) with ProDisc-C arthroplasty.

SUMMARY OF BACKGROUND DATA

Aggravation of kyphosis is the known challenge after Bryan disc arthroplasty. Both Bryan disc arthroplasty with modified techniques and ProDisc-C arthroplasty were reported to avoid the postoperative local kyphosis. There have been no studies comparing the alignment changes after Bryan disc arthroplasty with ProDisc-C arthroplasty.

METHODS

We conducted a randomized controlled clinical trial enrolling patients with cervical disc disease. Ultimately 20 patients received Bryan disc arthroplasty with modified surgical techniques and 26 patients received ProDisc-C arthroplasty. Functional spinal unit (FSU) and overall cervical alignment (Cobb angle of C2/7) were compared at final follow-up.

RESULTS

(1) FSU angle: the FSU angle was maintained for the Bryan disc group (from 0.8 to 0.6 degrees) without statistical significance; the FSU angle increased 2.9 degrees for the ProDisc-C group (from -0.3 to 2.6 degrees) with statistical significance. (2) Overall alignment: the overall alignments did not change for both Bryan disc and ProDisc-C groups.

CONCLUSIONS

Bryan disc arthroplasty with modified techniques can maintain the lordosis of FSU, whereas ProDisc-C arthroplasty can restore the lordosis of FSU. For the patients with preoperative FSU kyphosis, ProDisc-C arthroplasty may be a better choice to restore the lordosis.