Artikel
Radiographic evaluation of cervical spine segment settling characteristics in the presence of an anterior dynamic cervical plate
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Veröffentlicht: | 16. September 2010 |
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Objective: Dynamic cervical spine plates for anterior stabilisation have been successfully introduced into spinal surgery. There is evidence, that rate of implant complications is lower and speed of fusion is higher, however, loss of correction being more pronounced when compared to rigid plates. Detailed radiographic evaluation of settling properties may be helpful for better understanding of segmental healing and for improvement of implants. The objective of the current study is to analyze the settling characteristics in patients having received an anterior dynamic cervical plate.
Methods: The data analyzed was collected in a multicentric controlled randomized trial. All cases belong to the subgroup of monosegmental anterior dynamic plating (ABC, Aesculap AG, Tuttlingen, Germany). Parts of the study have already been published elsewhere, however not the current results. All radiographic measurements (57 patients) have been evaluated by an independent radiologist. We investigated the first 6 month safter surgery.
- 1.
- Plate sliding (PS, defined as the change in the distance between the cranial end of the plate and the upper endplate of the fixed segment).
- 2.
- change of screw position (SP) with respect to the cranial end of the plate,
- 3.
- PS vs. loss of segmental lordosis (LOL),
- 4.
- PS vs. loss of segmental height (LOH)
- 5.
- influence of plate slot length on LOH
- 6.
- SP vs Body Mass Index (BMI).
Results:
- 1.
- There was PS during the entire time, but it decreased significantly over time with respect to intraoperative x-ray (at discharge –0,4 mm (p=0.005), at 3 months –1.1 mm (p<0.001), at 6 months –1.2 mm (p=0.019)
- 2.
- SP changed significantly between time of discharge and 3 months (p<0.001), but not between three months and 6 months (p>0.05)
- 3.
- PS correlated significantly to LOL (r=0.602, p=0.001)
- 4.
- PS correlated significantly to LOH (r=0.388, p=0.028).
- 5.
- Plate slot length did not influence LOH (p>0.05, T-Test)
- 6.
- SP correlated significantly to BMI after 3 months (r=0.5, p=0.01) and after 6 months (r=0.56, p<0.001).
Conclusions: In anterior cervical fusions using dynamic plates, settling of the treated segment is most pronounced within the first three months and correlates with the LOL and LOH as well as BMI. The slots of the plate, however, do not influence settling. These data may illuminate our knowledge of cervical spine segmental healing as well as help to improve implants.