gms | German Medical Science

57th Annual Meeting of the German Society of Neurosurgery
Joint Meeting with the Japanese Neurosurgical Society

German Society of Neurosurgery (DGNC)

11 - 14 May, Essen

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Effectiveness of cemented rescue screws for anterior cervical plate fixation

Untersuchungen zur Effektivität von zementierten Schrauben zur Fixierung zervikaler Osteosyntheseplatten

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  • corresponding author T. Pitzen - Neurochirurgische Klinik, Universitätskliniken des Saarlandes, Homburg
  • J. Drumm - Neurochirurgische Klinik, Universitätskliniken des Saarlandes, Homburg
  • B. Bruchmann - Neurochirurgische Klinik, Universitätskliniken des Saarlandes, Homburg
  • D. Barbier - Neurochirurgische Klinik, Universitätskliniken des Saarlandes, Homburg
  • W. I. Steudel - Neurochirurgische Klinik, Universitätskliniken des Saarlandes, Homburg

Deutsche Gesellschaft für Neurochirurgie. Japanische Gesellschaft für Neurochirurgie. 57. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), Joint Meeting mit der Japanischen Gesellschaft für Neurochirurgie. Essen, 11.-14.05.2006. Düsseldorf, Köln: German Medical Science; 2006. DocFR.02.06

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/dgnc2006/06dgnc006.shtml

Published: May 8, 2006

© 2006 Pitzen et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

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Objective: There are different ways to optimize fixation of bone implants. Among those, bone cement is in common use to fix for example total-hip prosthesis. However, no data exist about the effectiveness of cemented rescue screws for anterior cervical plate fixation. The objective of this study was to investigate whether cemented rescue screws increase fixation strength with respect to uncemented standard screws.

Methods: Six human cervical spine segments (C4 – C7) were explanted during routine autopsy from fresh human cadavers. Bone mineral density (BMD) was measured for each vertebral body (VB) by a quantitative computerized tomography. 24 VB were dissected from the segments. Two initial pilot holes were drilled into each VB parallel to the sagittal plane. Based on the BMD, the specimens were assigned to one of two groups in which torque and pullout force were tested. The test was started with standard screws and repeated with cannulated slotted rescue screws in which bone cement was injected. Mean value of peak torque and pullout forces resulting from the single left/right measurements were used for statistical analysis. A t-test was performed to determine the effect of screw type on peak torque and pullout force. Moment correlation coefficients were calculated to determine the effect of BMD on peak torque and pullout force for each screw.

Results: Mean insertional peak torque for the standard screw was 67.1 N/cm and 102.6 N/cm for the cemented screw (p<0.05). Mean pullout force for standard osteoporosis screws was 526.9 N and 531.5 N for cemented screws (p>0.05). The effect of increased holding strength as measured by peak torque and pullout force was more pronounced in presence of low bone density.

Conclusions: Cemented rescue screws that have been inserted into a fatigued pilot hole in the cervical VB strengthen the screw-bone interface compared with the strength initially conferred by a standard screw.