Article
Fusion rate and failure rate following anterior cervical plating with dynamic or rigid plates: Results of a multi-centric, prospective, randomized, controlled study
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Authors
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T. Pitzen
- Neurochirurgische Klinik, Universitätsklinik des Saarlandes, Homburg, Germany
| Published: | September 28, 2006 |
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Outline
Text
Anterior cervical plate fixation is an approved technique for cervical spine stabilization in the presence of anterior cervical instability. Rigid plate designs, in which the screws are locked to the plate, are in common use and thought to provide more fixation to an injured segment than dynamic designs, in which the screws may glide when the graft is settling. Recently, mechanical studies gave evidence, that dynamic anterior plates provide more loading on the graft thus resulting in a more rapid fusion and – as a consequence - lower implant complications. This, however, must not be necessarily true under in vivo conditions. Thus, the aim of the study was to analyse speed of fusion and implant complications in both type of plates.
Methods: This is a prospective, randomized, controlled multi-centric study, approved by the competent ethic committees of each participating country. 132 patients were included and assigned by randomisation to one of the groups in which they received a routine anterior cervical discectomy and autograft fusion with either a dynamic plate with screws locked in ap – direction (ABC) or a rigid plate (CSLP). After 3 and 6 months (mos), we looked at the following radiographic data: segmental mobility and implant complications or failed fusion, respectively. All measurements were performed by an independent radiologist.
Results: 6 mos mobility results were available for 71 patients (39 ABC / 32 CSLP). Baseline (immediately postop or at discharge) mean segmental motility for the ABC group was 1,67 mm , 1,37 mm after 3 mos and 0,5 mm after 6 mos. For the CSLP- group these values were 0,95 mm, 1,9 mm and 1,88 mm. The difference at 6 mos between both groups is significant (p = 0,009). There have been 4 patients with hardware complications within the CSLP – group (n=41) and no implant complications within the ABC – group (n=45), p = 0.048, Fisher’s Exact test.
Conclusion: There is evidence, that dynamic plate designs provide a more rapid fusion in cervical spine surgery than rigid plate designs. Moreover, the rate of implant complications tends to be lower in this group. To date, these interim results are just true for the 6-mos follow up period.
