Cortical Margining Capabilities of Fins significant difference was observed between con- ditions B and C regarding stiffness, the condition C specimens were 11% stiffer than the condition B specimens. This suggests that a somewhat favorable result might be obtained in a clinical situation or under other experimental conditions. The condition C (fins and screws) specimens showed the greatest yield loads. This was fol- lowed by condition B (screws alone) and then condition A (fins alone). The yield strength of the specimens employing both fins and screws is roughly equal to the sum of the yield strengths of the specimens employing screws (condition B) and the specimens employing fins (condition A). In contrast to the stiffness results, the condition C specimens showed significantly greater yield loads compared to condition A and condition B. The condition C specimens had 40% larger yield loads compared to the condition B specimens. This result indicates that yield load is mainly affected by the screw component, rather than the fins. Also, this result showed that the addition of the fin components to the DOC ventral cervical plating system provides an augmentation of the axial load-bearing capacity of the construct. In fact, the axial load-bearing capacity (i.e. yield load) effect of the screws and fins appears to be additive, with the screws contributing approxi- mately two-thirds and the fins contributing one- third of the overall capacity. In this study, upper thoracic vertebral bodies were tested instead of cervical vertebral bodies due to specimen availability. The magnitudes of the parameters measured in the current study may therefore have differed if cervical spines were tested. However, the trends observed in this study are not expected to differ from the trends that may be revealed in the testing of cervical levels. In the current study, specimens to which plat- forms were attached using screws alone had approximately twice the stiffness of those using fins alone. The specimens with both fins and screws had nearly twice the yield load of the specimens with screws alone. This study demon- strated that the addition of fins significantly in- creased the construct stability (axial load-bearing stability) by approximately 34%. The screws con- tributed two-thirds of the overall axial load- bearing capacity, and the fins contributed the remaining one-third towards this stability. The addition of fins provided a buttress effect against the cortical margin of the vertebral body in an additive manner to that provided by screws, thus augmenting the stability of the construct. REFERENCES 1. DiAngelo DJ, Foley KT, Vossel KA, Rampersaud YR, Jansen TH. Anterior cervical plating reverses load transfer through multilevel strut-grafts. Spine 2000;25: 783-95. 2. Wang JL, Panjabi MM, Isomi T. The role of bone graft force in stabilizing the multilevel anterior cervical spine plate system. Spine 2000;25:1649-54. 3. Brodke DS, Gollogly S, Mohr RA, Nguyen BH, Dailey AT, Bachus KN. Dynamic cervical plates: Biomechani- cal evaluation of load sharing and stiffness. Spine 2001; 26:1324-9. 4. Clausen JD, Ryken TC, Traynelis VC, Sawin PD, Dexter F, Goel VJ. Biomechanical evaluation of Caspar and cervical spine locking plate systems in a cadaveric model. J Neurosurg 1996;84:1039-45. 5. Grubb MR, Currier BL, Shin JS, Bonin V, Grabowski JJ, Chao EYS. Biomechanical evaluation of anterior cervical spine stabilization. Spine 1998;23:886-92. 6. Kanayama M, Cunningham MS, Weis JC, Parker LM, Kaneda K, McAfee PC. The effect of rigid spinal instrumentation and solid bony fusion on spinal kine- matics. Spine 1998;23:767-73. 7. Koh YD, Lim TH, You JW, Eck J, An HS. A bio- mechanical comparison of modern anterior and poste- rior fixation of the cervical spine. Spine 2001;26:15-21. 8. Spivak JM, Chen D, Kummer FJ. The effect of locking fixation screws on the stability of anterior cervical plating. Spine 1999;24:334-8. 9. Brown JA, Havel P, Ebrahein N, Greenblatt SH, Jackson WT. Cervical stabilization by plate and bone fusion. Spine 1988;13:236-40. 10. Newman M. The outcome of pseudoarthrosis after cervical anterior fusion. Spine 1993;18:2380-2. 11. Vaccaro AR, Falatyn SP, Scuderi GJ. Early failure of long segment anterior cervical plate fixation. J Spinal Disord 1998;11:410-5. 12. Benzel EC. Biomechanics of spine stabilization. Ameri- can association of neurological surgeons 2001:155-70, 431-51. 13. Wang JC, Zou D, Yuan H, Yoo J. A biomechanical evaluation of graft loading characteristics for anterior cervical discectomy and fusion. Spine 1998;23:2450-4. 14. Robinson RA, Walker AE, Ferlic DC, Wiecking DK. The results of anterior interbody fusion of the cervical spine. J Bone Joint Surg 1962;44:1569-86. 15. Silva MJ, Keaveny TM, Hayes WC. Load sharing Yonsei Med J Vol. 46, No. 3, 2005