316 - Is the Incidence of Adjacent Level Heterotrophic Ossification Greater...

#316 Is the Incidence of Adjacent Level Heterotrophic Ossification Greater in Anterior Cervical Discectomy and Fusion vs. Cervical Total Disk Arthroplasty?

Cervical Therapies and Outcomes

Poster Presented by: W. Neway

Author(s):

W.E. Neway (1)
J. Yue (1)

(1) Yale University, Orthopaedics, New Haven, CT, USA

Abstract

Background: Cervical total disc arthroplasty is a motion sparing technology to address cervical spondylosis for which fusion has long been the treatment of choice. It has been shown that restoring physiologic motion decreases the biomechanical forces placed at levels adjacent to spinal fusions.

Purpose: To investigate whether or not cervical total disk arthroplasty has a lower incidence of adjacent level heterotrophic ossification than anterior cervical discectomy and fusion.

Study Design/Setting: Patients were evaluated retrospectively from a single site/single surgeon who had undergone single level cervical total disc arthroplasty or anterior cervical discectomy and fusion.

Patient Sample: All patients were part of the Prodisc (38) cervical prospective clinical trials.

Methods: Radiographs of patients undergoing a single-level cervical total disk arthroplasty or anterior cervical discectomy and fusion from C4-7 were evaluated for the presence or absence of adjacent level heterotrophic ossification at a minimum follow-up of 6 years. In those patients with adjacent level disease, cephalad or caudad location and the degree (Grade 0-III) of ossification was documented. Additionally, those undergoing cervical total disc arthroplasty were evaluated for the degree of ossification (Grade 0-III) across the motion segment.

Summary: 38 patients were included in analysis. The average follow-up for all patients was 6 yrs. The prevalence of adjacent level heterotrophic ossification among all patients was 34% (N=38). The prevalence of adjacent level heterotrophic ossification among patients undergoing cervical total disc arthroplasty was 29% (N=27). The prevalence of adjacent level heterotrophic ossification among patients undergoing anterior cervical discectomy and fusion was 64% (N=11). The prevalence of adjacent level heterotrophic ossification across the motion segment in patients undergoing cervical total disc arthroplasty was 52% (N=27).

Conclusions: In our limited group of patients undergoing treatment for cervical spondylosis, those treated with cervical total disk arthroplasty demonstrated a lower incidence of adjacent level heterotrophic ossification compared to anterior cervical discectomy and fusion. Anecdotally, those patients undergoing cervical total disk arthroplasty that showed ossification across the motion segment did not limit radiographic motion. Further investigation as to the effects of motion sparing technology and surgical techniques should be further explored.