Incidence of Fusion Across Total Disc Replacement with Heterotopic Ossification: Are Ball and Socket Disc Replacements Fusing with and without Radiographic Evidence.

Presented at SMISS Annual Forum 2018
By Fabio Pencle MBBS
With D. Zhao , O. Johnson , F. Sandhu , J. Voyadzis ,

Disclosures: Fabio Pencle MBBS None D. Zhao None, O. Johnson None, F. Sandhu None, J. Voyadzis None,

Introduction:

Total disc replacement (TDR) is a motion preserving technique that closely reproduces physiologic kinematics of the cervical spine. However, heterotopic ossification (HO) and spontaneous fusion after implantation of the total cervical disc have been reported in several studies to decrease the range of motion postulated by in vitro and in vivo biomechanical studies.

Aims/Objectives:

The authors aim to review outcomes and complications of ball and socket total disc replacements.

Methods:

The medical records of 117 consecutive patients undergoing cervical TDR over a five-year period with Mobi-C, Prodisc-C, Prestige LP and Secure-C implants were followed. Outcomes assessed included VAS neck and arm and NDI scores. Radiographic assessment looked at heterotopic ossification leading to fusion and complication rates.

Results:

Of 117 patients that underwent TDR, 56% were male with the group’s mean age being 46.2+/-10.3 years and BMI of 18.9+/-13.6 kg/m2. Longest follow-up was 5 years with Prodisc-C group, with overall fusion noted in 16% of patients. One patient was also noted to have fusion which was not seen radiographically but noted intraop for adjacent segment disease. There has been no demonstrable radiographic fusion seen in the Prestige-LP group, however, the follow-up has only been 12-24 months for this group.

Conclusions:

In this study, we have demonstrated radiographic fusion anterior to the ball and socket total disc replacement as well as the uncovertebral joint. We postulate that with the use of a mobile core disc there is an increased potential for fusion leading to a non-functional disc replacement.