Biomechanical comparision of the stable efficacy of two anterior plating systems


      Objective. To compare the immediate stable efficacy and load sharing effect of two types of anterior cervical screw-plating instrumentations: the Morscher Synthes titanium locking screw-plate system and the Caspar trapezoidal screw-plate system.
      Design. Fresh porcine cervical spines with intact, two surgery unstable models, and then reconstructed with or without screw-plating instruments were compared in three physiological loading conditions.
      Background. Two markedly instrumentation systems––Morscher Synthes titanium cervical locking screw-plate and Caspar trapezoidal screw-plate systems are commonly used in management of complex cervical spine disorders. Although the biomechanical study showed that the lower cost Caspar system performed superior in extension before and after plate fatigue, the clinic evaluations of two systems were contradictory. So (1) does the titanium cervical locking plate system pay for its higher cost? and (2) what is the load sharing character of strut graft in one level corpectomy?
      Methods. Eight fresh ligamentous porcine cervical spines from C3 to C7 were undergone axial compression, rotation and sagittal flexion tests. The biomechanical experiment was sequentially repeated for the intact, C5-6 discectomy, C5 corpectomy, and then stabilized by either type of plate fixation devices with or without polymethylmethacrylate bone cement grafting. Strains measured by an extensometer across the operated motion segment were used as the index of stability.
      Results. Analysis of the strain data showed both types of anterior fixation plate systems provided adequate-restored stability for the spinal column only aided with polymethylmethacrylate construction. Statistically, there was no significant difference in biomechanical evaluation for the stability effect between much cost Morscher Synthes plate and Caspar plate system (p<0.005). The spinal disc bore as much as 75% of axial loading. While the strut graft functioned as the disc substitute and spacer, it bore more than 90% of axial loading. In high degree of flexion, the transmitted compressive load was shifted anteriorly to the screw-plate. This might unload the polymethylmethacrylate graft and resulted in the strut graft in tensile fatigue failure.
      Conclusions. Statistically both systems showed similar stable efficacy, however, the Morscher Synthes cervical locking plate system might provide better stable effect in higher degrees of flexion motion. The strut graft played as the major load-bearing role in axial compression and sagittal flexion, while in axial rotation, the applied torque was mainly resisted by facet joint and screw-plate system complex.Relevance
      The minor discrepancy of two plating systems may be due to the nature of plate geometry and design but not the material properties. Combination of bone graft and either plating systems provides adequate fusion stability under physiological loadings. The high degree flexion may cause the posterior portion of polymethylmethacrylate graft in tensile fracture and then result in polymethylmethacrylate failure in clinic observation.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Clinical Biomechanics
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Aebi M.
        • Zuber K.
        Treatment of cervical spine injuries with anterior plating, indications, techniques, and results.
        Spine. 1990; 16: S38-S45
        • Baldwin N.G.
        • Hartman G.P.
        • Weiser M.W.
        • Benzel E.C.
        Failure of a titanium anterior cervical plate implant; microstructural analysis of failure, case report.
        J. Neurosurg. 1995; 83: 741-743
        • Bose B.
        Anterior cervical fusion using Caspar plating: analysis of results and review of the literature.
        Surg. Neurol. 1998; 49: 25-31
        • Caspar W.
        • Barbier D.D.
        • Klara P.M.
        Anterior cervical fusion and Caspar plate stabilization for cervical trauma.
        Neurosurgery. 1989; 25: 491-502
        • Caspar W.
        • Geisler F.H.
        • Pitzen T.
        • Johnson T.A.
        Anterior cervical plate stabilization in one- and two-level degenerative disease: overtreatment or benefit.
        J. Spinal Disorders. 1998; 11: 1-11
        • Caspar W.
        • Pitzen T.
        • Papavero L.
        • Geisler F.H.
        • Johnson T.A.
        Anterior cervical plating for the treatment of neoplasms in the cervical vertebrae.
        J. Neurosurg. 1999; 90: 27-34
        • Clausen J.D.
        • Ryken T.C.
        • Traynelis V.C.
        • Sawin P.D.
        • Dexter F.
        • Goel V.K.
        Biomechanical evaluation of Caspar and cervical spine locking plate systems.
        J. Neurosurg. 1996; 84: 1039-1045
        • Clements D.H.
        • O’Leary P.F.
        Anterior cervical discectomy and fusion.
        Spine. 1990; 15: 1023-1025
        • Connolly P.J.
        • Esses S.I.
        • Kostuik J.P.
        Anterior cervical fusion: outcome analysis of patients fused with and without anterior cervical plates.
        J. Spinal Disorders. 1996; 9: 202-206
        • DiAngelo D.J.
        • Foley K.T.
        • Vossel K.A.
        • Rampersaud Y.R.
        • Jansen T.H.
        Anterior cervical plating reverses load transfer through multilevel strut-grafts.
        Spine. 2000; 25: 783-795
        • Goel V.K.
        • Clausen J.D.
        Prediction of load sharing among spinal componets of a C5-C6 motion segment using the finite element approach.
        Spine. 1998; 23: 684-691
        • Grubb M.R.
        • Currier B.L.
        • Shih J.S.
        • Bonin V.
        • Grabowski J.J.
        • Chao E.Y.
        Biomechanical evaluation of anterior cervical spine stabilization.
        Spine. 1998; 23: 886-892
        • Herman J.M.
        • Sonntag V.K.
        Cervical corpectomy and plate fixation for postlaminectomy kyphosis.
        J. Neurosurg. 1994; 80: 963-970
        • Kostuik J.P.
        • Connolly P.J.
        • Esses S.I.
        • Suh P.
        Anterior cervical plate fixation with the titanium hollow screw plate system.
        Spine. 1993; 18: 1273-1278
        • Lowery G.L.
        • McDonough R.F.
        The significance of hardware failure in anterior cervical plate fixation. Patients with 2- to 7-year follow-up.
        Spine. 1998; 23: 181-186
        • Malca S.A.
        • Roche P.H.
        Cervical interbody xenograft with plate fixation, evaluation of fusion after 7 years of use in post-traumatic discoligamentous instability.
        Spine. 1996; 21: 685-690
        • Miller D.J.
        • Lang F.F.
        • Walsh G.L.
        • Abi-Said D.
        • Wildrick D.M.
        • Gokaslan Z.L.
        Coaxial double-lumen methylmethacrylate reconstruction in the anterior cervical and upper thoracic spine after tumor resection.
        J. Neurosurg. 2000; 92: 181-190
        • Morscher E.
        • Sutter F.
        • Jenny H.
        • Olerud S.
        Anterior plating of the cervical spine with hollow screw-plate system of titanium.
        Chirurg. 1986; 57: 702-707
      1. Muller M.E. Allgower M. Schneider R. Willenegger H. Manual of Internal Fixation. third ed. Springer-Verlag, 1991
        • Natio M.
        • Kurose S.
        • Oyama M.
        • Sugioka Y.
        Anterior cervical fusion with the Caspar instrumentation system.
        Int. Orthopaedics. 1993; 17: 73-76
        • Randle M.J.
        • Wolf A.
        • Levi L.
        • Rigamonti D.
        • Mirvis S.
        • Robinson W.
        • Bellis E.
        • Greeberg J.
        • Salcman M.
        The use of anterior Caspar plate fixation in acute cervical spine injury.
        Surg. Neurol. 1991; 36: 181-189
        • Rapoff A.J.
        • O’Brien T.J.
        • Ghanayem A.J.
        • Heisey D.M.
        • Zdeblick T.A.
        Anterior cervical graft and plate load sharing.
        J. Spinal Disorders. 1999; 12: 45-49
        • Schitz Jr., K.D.
        • McLaughlin M.R.
        • Haid Jr., R.W.
        • Comey C.H.
        • Rodts Jr., G.E.
        • Alexander J.
        Single stage anterior-posterior decompression and stabilization for complex cervical spine disorders.
        J. Neurosurg. 2000; 93: 214-221
        • Spivak J.M.
        • Chen D.
        • Kummer F.J.
        The effect of locking fixation screws on the stability of anterior cervical plating.
        Spine. 1999; 24: 334-338
        • Suh P.B.
        • Kostuik J.P.
        • Esses S.I.
        Anterior cervical plate fixation with the titanium hollow screw plate system, A preliminary report.
        Spine. 1990; 15: 1079-1081
        • Tominaga T.
        • Koshu K.
        • Mizoi K.
        • Yoshimoto T.
        Anterior cervical fixation with the titanium locking screw-plate: a preliminary report.
        Surg. Neurol. 1994; 42: 408-413
        • van den Bent M.J.
        Anterior cervical discectomy with or without fusion with acrylate, a randomized trial.
        Spine. 1996; 21: 834-840
        • Wang J.L.
        • Panjabi M.M.
        • Isomi T.
        The role of bone graft force in stabilizing the multilevel anterior cervical spine plate system.
        Spine. 2000; 25: 1649-1654
        • Wang J.C.
        • McDonough P.W.
        • Endow K.K.
        • Delamarter R.B.
        A comparison of fusion rates between single-level cervical corpectomy and two-level discectomy and fusion.
        J. Spinal Disorders. 2001; 14: 222-225
        • White III, A.A.
        • Panjabi M.M.
        Clinic Biomechanics of the Spine.
        second ed. JB Lippincott Co, 1990
        • Zeega B.
        • Karrholm J.
        • Lind B.
        One-level cervical spine fusion, A randomized study with or without plate fixation, using radiostereometry in 27 patients.
        Acta Orthop. Scand. 1998; 69: 263-268