Article
Error analysis after monosegmental ventral decompression and implantation of a Discover™ cervical disc prosthesis – a prospective study
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Authors
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M. Klingenhöfer
- Neurochirurgische Klinik, Heinrich-Heine-Universität Düsseldorf
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F. Floeth
- St. Vinzenz-Krankenhaus, Düsseldorf
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R. Bostelmann
- Neurochirurgische Klinik, Heinrich-Heine-Universität Düsseldorf
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H.-J. Steiger
- Neurochirurgische Klinik, Heinrich-Heine-Universität Düsseldorf
| Published: | May 20, 2009 |
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Outline
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Objective: The MR-compatible hybrid titanium prosthesis „Discover™” allows simple and fast handling during the implantation as well as the use in patients with a cervical myelopathy. In order to critically review the results of the first implantations, an error analysis took place within a prospective observation study.
Methods: 77 patients with monosegmental, symptomatic findings of a cervical disc and failure of conservative therapy underwent operative therapy between January and December 2007. In 51 cases PEEK cage fusion was performed, in 26 cases disc prostheses were used after ventral decompression. In 18 patients the “Discover™” disc prosthesis (DePuy Spine) was used. Radiculopathy was the indication in 11 cases, myelopathy in 7 cases. Clinical and radiological evaluations including conventional X-rays of the cervical spine with motion imaging were done pre- and postoperatively as well as at a 3 month visit.
Results: There were no intra- or postoperative complications in the group of the 18 disc prostheses. Clinically, no significant differences were detected between the cage fusions and the disc prostheses. An average pain reduction from VAS 7 to 2 could be achieved in both groups. At the 3 month visit preserved segment mobility was radiologically detectable in 16 of 18 cases. In one patient a heterotopic ventral ossification was observed, and another patient showed an asymptomatic dislocation of the prosthesis after a step fall requiring a revision procedure. A radiologically optimal adjustment of the prosthesis size to the segment was achieved in 11 patients. Despite optimal intraoperative placement of all prostheses, postoperative controls demonstrated anterior motion of the cranial plate related to the caudal prosthesis plate in nine cases (which was not relevant for the clinical outcome). Both “the false sizes” and “the relative plate motions” were observed only in patients with preexisting segment degeneration.
Conclusions: The implantation of the Discover™ cervical disc prosthesis is safe, does not extend the duration of the procedure and preserves the possibility of a postoperative MRI evaluation of the operated segment. In order to avoid heterotopic ossification the prosthesis has to fit into the disc space optimally. In case of a pre-existing segment degeneration there is a tendency of subluxation of the prosthesis with anterior motion of the cranial plate.
