Subsidence of the wing titanium cage after anterior cervical interbody fusion: 2-year follow-up study.
OBJECTIVE
Cage subsidence occurs after anterior cervical discectomy and fusion (ACDF). The aim of this prospective study was to evaluate subsidence and total segmental height after implantation of a newly designed Wing titanium cage. Furthermore, alignment of the entire cervical spine was analyzed 2 years after surgery.


METHODS
Fifty-four patients (26 women and 28 men) whose mean age was 48.3 years underwent ACDF. Follow-up examinations were performed at discharge and 6, 12, and 24 months postoperatively by an independent investigator. The clinical course was evaluated using the visual analog pain scale and the Prolo scales. Measurements of subsidence and total segmental height were conducted, and the alignment of the entire cervical spine was classified using two methods. In 54 patients 64 levels were fused. The patients noted a significant reduction of pain, and scores on both Prolo scales were significantly improved. At the 2-year follow-up examination, subsidence was present in 30 of the 67 fused segments. There was a statistically significant correlation between subsidence and the presence of posterior spondylosis at the initial surgery. Furthermore, there was a significant correlation between reduction of total segmental height and the presence of subsidence; however, subsidence did not prevent the development of a solid bone arthrodesis (fusion rate 98%) or have an adverse effect on the alignment of the cervical spine.


CONCLUSIONS
Titanium Wing cage-augmented ACDF was associated with comparatively good long-term results. Subsidence was present but did not cause clinical complications. Furthermore, radiological studies demonstrated that the physiological alignment of the cervical spine was preserved and a solid bone arthrodesis was present at 2 years after surgery.
Schmieder
Kirsten
K
Department of Neurosurgery, Ruhr-University Bochum, Germany. kirsten.schmieder@ruhr-uni-bochum.de
Wolzik-Grossmann
Markus
M
Pechlivanis
Ioannis
I
Engelhardt
Martin
M
Scholz
Martin
M
Harders
Albrecht
A
D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae; D017586:Diskectomy; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016268:Internal Fixators; D007405:Intervertebral Disc Displacement / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography; D013123:Spinal Fusion / Q000295:instrumentation*; D014025:Titanium; D016896:Treatment Outcome
D014025:Titanium