The Assessment of Paravertebral Ossification Progression After Cervical Disc Arthroplasty Based on CT Images: A Long‐term Follow‐up

Abstract

This study focused on the assessment of paravertebral ossification (PO) after cervical disc arthroplasty (CDA) using computed tomography (CT) images. Methods: In this retrospective study, 52 patients (from 2004 to 2010) who received CDA at a single center were included (32 males). Preoperative and follow-up X-ray and CT images of all patients who underwent single-level CDA were collected. PO from the C2/3 to C7/T1 in each patient was graded based on a CT grading system. Each segment was divided into operative level, adjacent level, or non-adjacent level. The McAfee' classification system was used to grade PO using X-ray plain film. The range of motion (ROM) and scores of neurological symptoms (Japanese Orthopaedic Association [JOA] score and Neck Disability Index [NDI]) at both preoperative and final follow-up time were acquired. Progression and classification of PO in each group was compared using the chi-square test. ROM between groups were compared using independent t-test. JOA score and NDI between groups were compared using Mann-Whitney U test. Results: The average follow-up time was 81.2 months. In comparison with the preoperative status, the progression of PO development in left and right areas (the Luschka joints areas) in the operative level groups was significantly more severe (area L,χ 2 value = 36.612, P < 0.001; area R, χ 2 value = 39.172, P < 0.001) than the non-adjacent level groups. In contrast, although the prevalence of PO in all areas of the adjacent level groups was higher than that of the non-adjacent level group in the same segments, there was no significant difference (P > 0.05) in the progression of PO development. The follow-up high-grade (grades III and IV) PO incidence rate using X-ray grading system (3.85%) was significantly lower than that using CT grading system in area L (42.31%) and R (38.46%), but close to that in area A (5.77%) and P (1.92%). The final follow-up ROM was not significantly different with preoperative ROM in patients with low-grade PO (9.47 ± 4.12 vs. 9.76 ± 3.69 , P = 0.794). However, in patients with high-grade PO, the final followup ROM was significantly lower than preoperative ROM (5.77 ± 3.32 vs. 9.28 ± 4.15 , P < 0.001). There was no significant difference for JOA score and NDI at follow-up between patients with high-grade and low

Risk Factors for High-Grade Heterotopic Ossification After Total Disc Replacement: A Single-Center Experience of 394 Cases

“…In our study, no differences in clinical outcomes were found between patients with and without HO. Consistent with our results, Zeng et al's 23 retrospective study of 52 patients with TDR showed no significant differences between preoperative and the final ROM in patients with low-grade paravertebral ossification. A meta-analysis of 444 patients showed that HO was not associated with clinical outcomes, but high-grade HO had a significantly higher VAS score than low-grade HO group.…”

Observational, Multicenter Study of the Efficacy and Safety of Cervical Disk Arthroplasty With Mobi-C in the Treatment of Cervical Degenerative Disk Disease. Results at 10 years Follow-Up

“…Mehren et al 19 also noted this evolution. Grade IV HO rates in CDA patients have been reported in the range of 8% to 33% at 10 years 15,17,19,21,33–35. In a systematic review, Kong et al 35 reported evolving rates of severe HO, from 22.2% at two to five years to 47.5% at 10 years.…”

Cervical Disc Arthroplasty for the Treatment of Noncontiguous Cervical Degenerative Disc Disease: Results of Mid‐ to Long‐Term Follow‐up

“…14 The occurrence of heterotopic ossification (HO) was graded according to the McAfee classification system 16 and was divided into low-grade HO (0-II) and high-grade HO (III-IV) based on impaired ROM criteria. 17,18 Anterior bone loss (ABL) was evaluated using Kieser's methods 14,19 (Figure 2). The adjacent segment degeneration (ASDeg) was semi-quantitatively evaluated based on the overall degeneration of height loss (graded from 0 to 4), anterior osteophytes (graded from 0 to 3), and endplate sclerosis (graded from 0 to 2).…”