[The x-ray follow-up study of the cervical spine after anterior fusion with titanium disk implants].

PURPOSE: We examined the postoperative changes of the cervical spine after treatment of cervical nerve root compression with anterior cervical discectomy and fusion with a new titanium intervertebral disc. PATIENTS AND METHODS: 37 patients were examined prior to, as well as 4 days, 6 weeks, and 7 months after surgery. Lateral view X-rays and functional imaging were used to evaluate posture and mobility of the cervical spine, the position of the implants, and the reactions of adjacent bone structures.
RESULTS: Implantation of the titanium disc led to post-operative distraction of the intervertebral space and slight lordosis. Within the first 6 months a slight loss of distraction and re-kyphosis due to impression of the implants into the vertebral end-plates were found in all patients. We noted partial infractions into the vertebral end-plates in 10/42 segments and slight mobility of the implants in 14/42 segments. Both groups of patients showed reactive spondylosis and local symptoms due to loosening of the implants. The pain subsided after onset of bone bridging and stable fixation of the loosened discs.
CONCLUSIONS: The titanium intervertebral disc provides initial distraction of the fusion segments with partial recurrence of kyphosis during the subsequent course. Loosening of the implants with local symptoms can be evaluated with follow-up X-rays and functional imaging.