Postoperative Heterotopic Ossification After Cervical Disc Replacement Is Likely a Reflection of the Degeneration Process.
BACKGROUND
The cause of postoperative heterotopic ossification (HO) after cervical disc replacement (CDR) is unclear. The aim of the present study was to investigate the incidence of HO, its clinical significance, and whether the degree of preoperative degeneration was associated with its occurrence.


METHODS
Patients who had undergone CDR using the Prestige-LP disc with a minimum of 48 months of follow-up were included. The patients were divided into 2 groups stratified by the presence of HO. The clinical outcomes (visual analog scale for neck and arm pain, neck disability index, and Japanese Orthopaedic Association scores) and radiographic parameters were collected and analyzed pre- and postoperatively and compared between the 2 groups. The preoperative degeneration at the operated levels was evaluated using the Kellgren-Lawrence scale and Miyazaki magnetic resonance imaging grading system.


RESULTS
A total of 69 patients (89 levels) were identified, and the average age at surgery was 45.8 years. The overall incidence of HO at the final follow-up visit was 37.7% (26 of 69 of patients), and an increasing incidence and severity of HO was observed during the follow-up period. Significant and maintained improvements for all clinical outcome measures were observed, and the presence of HO did not influence these improvements. Segments with greater severe preoperative degeneration had a greater incidence of HO (P < 0.01). However, no statistical significant correlation between the degree of preoperative degeneration and the grade of HO was observed.


CONCLUSION
The presence of HO after CDR was a relatively frequent finding at the final follow-up visit but did not influence patients' improvements. Segments with higher grades of preoperative degeneration had a greater incidence of HO; thus, HO is likely a reflection of the degeneration process.
['Li|Guangzhou|G|', 'Wang|Qing|Q|', 'Liu|Hao|H|', 'Yang|Yi|Y|']
D000328:Adult D002574:Cervical Vertebrae D005260:Female D006801:Humans D055959:Intervertebral Disc Degeneration D008297:Male D008875:Middle Aged D009999:Ossification, Heterotopic D011183:Postoperative Complications D012189:Retrospective Studies D059145:Total Disc Replacement D016896:Treatment Outcome
Heterotopic ossification Cervical disc replacement Degeneration Adjacent segment degeneration Spondylosis