Anterior cervical plating reverses load transfer through multilevel strut-grafts.

STUDY DESIGN In vitro biomechanical study using a programmable testing apparatus that replicated physiologic flexion/extension cervical spine motion and loading mechanics. OBJECTIVE To determine the influence of anterior plating on multilevel cervical strut-graft mechanics in vitro. SUMMARY OF BACKGROUND DATA The addition of anterior instrumentation does not prevent construct failure in multilevel cervical corpectomy. METHODS Six fresh human cadaveric cervical spines (C2-T1) were tested in the four following sequential conditions: harvested, C4-C6 corpectomy, strut-grafted, and strut-grafted with an anterior cervical plate. A force-sensing strut-graft was used to measure compression/tension, flexion/extension and lateral bending moments, and axial torsion. Parameters of stiffness, vertebral motion, and strut-graft loads were compared to determine differences between the four spine conditions. RESULTS Application of the anterior plate significantly increased the global stiffness (P < 0.01) and decreased the local motion (P < or = 0.01) of the instrumented levels (C3-C7). Flexion of the strut-grafted spine loaded the strut-graft, whereas extension unloaded the strut-graft. With the anterior plate, flexion of the plated spine unloaded the strut-graft. Extension significantly loaded the strut-graft more than similar degrees of flexion in the strut-grafted condition (P = 0.01). Strut-graft loading end limits of 225 N were reached with a mean 7.5 degrees extension in the plated spines. CONCLUSIONS Anterior multilevel cervical plating effectively increases stiffness and decreases local cervical motion after corpectomy. However, anterior cervical plating also reverses graft loads and excessively loads the graft in extension, which may promote pistoning and failure of multilevel constructs.

[1]  P. McAfee,et al.  A Biomechanical Evaluation of Cervical Spinal Stabilization Methods in a Bovine Model: Static and Cyclical Loading , 1988, Spine.

[2]  Jeffrey A. Brown,et al.  Cervical Stabilization by Plate and Bone Fusion , 1988, Spine.

[3]  L. Claes,et al.  Biomechanics of Fixation Systems to the Cervical Spine , 1991, Spine.

[4]  D. Kunz,et al.  Anterior Cervical Discectomy, Fusion, and Plating: A Comparative Animal Study , 1993, Spine.

[5]  N. Bogduk,et al.  Instantaneous axes of rotation of the typical cervical motion segments: I. an empirical study of technical errors. , 1991, Clinical biomechanics.

[6]  F. Eismont,et al.  Anterior Decompression, Structural Bone Grafting, and Caspar Plate Stabilization for Unstable Cervical Spine Fractures and/or Dislocations , 1992, Spine.

[7]  B. Cunningham,et al.  A biomechanical analysis of decompression and reconstruction methods in the cervical spine. Emphasis on a carbon-fiber-composite cage. , 1993, The Journal of bone and joint surgery. American volume.

[8]  V. Askins,et al.  Efficacy of Five Cervical Orthoses in Restricting Cervical Motion: A Comparison Study , 1997, Spine.

[9]  T. Zdeblick,et al.  Cervical kyphosis and myelopathy. Treatment by anterior corpectomy and strut-grafting. , 1989, The Journal of bone and joint surgery. American volume.

[10]  A Rohlmann,et al.  Multichannel strain gauge telemetry for orthopaedic implants. , 1988, Journal of biomechanics.

[11]  M M Panjabi,et al.  Cervical Spine Stabilization: A Three‐Dimensional, Biomechanical Evaluation of Rotational Stability, Strength, ami Failure Mechanisms , 1991, Spine.

[12]  J. Kostuik,et al.  Anterior cervical plate fixation with the titanium hollow screw plate system. A preliminary report. , 1990 .

[13]  M. Swank,et al.  Rigid internal fixation with lateral mass plates in multilevel anterior and posterior reconstruction of the cervical spine. , 1997, Spine.

[14]  A. Nordwall,et al.  Forces and motions across the neck in patients treated with halo-vest. , 1988 .

[15]  S. Emery,et al.  The Pathophysiology of Cervical Spondylosis and Myelopathy , 1988, Spine.

[16]  T Yamamuro,et al.  Analysis and Prevention of Spinal Column Deformity Following Cervical Laminectomy I: Pathogenetic Analysis of Postlaminectomy Deformities , 1991, Spine.

[17]  J. Kostuik,et al.  Pitfalls of Biomechanical Testing , 1991, Spine.

[18]  S. Shapiro.  Banked fibula and the locking anterior cervical plate in anterior cervical fusions following cervical discectomy. , 1996, Journal of neurosurgery.

[19]  M. R. Mclaughlin,et al.  Cost advantages of two-level anterior cervical fusion with rigid internal fixation for radiculopathy and degenerative disease. , 1997, Surgical neurology.

[20]  M. Bernstein,et al.  Multilevel anterior cervical corpectomy and fibular allograft fusion for cervical myelopathy. , 1997, Journal of neurosurgery.

[21]  M. Botte,et al.  Complications in the use of the halo fixation device. , 1986, The Journal of bone and joint surgery. American volume.

[22]  M M Panjabi,et al.  Functional Radiographic Diagnosis of the Cervical Spine: Flexion/Extension , 1988, Spine.

[23]  M. Ebersold,et al.  Surgical treatment for cervical spondylitic myelopathy. , 1995, Journal of neurosurgery.

[24]  R. Balderston,et al.  Anterior Plate Instrumentation for Disorders of the Subaxial Cervical Spine , 1997, Clinical orthopaedics and related research.

[25]  M. Krag,et al.  Clinical, Radiographic, and Kinematic Results From an Adjustable Four-Pad Halovest , 1997, Spine.

[26]  Augustus A. White,et al.  Biomechanical Considerations in the Surgical Management of Cervical Spondylotic Myelopathy , 1988, Spine.

[27]  J. C. D. Oliveira.  Anterior plate fixation of traumatic lesions of the lower cervical spine. , 1987 .

[28]  J. Fischgrund,et al.  Anterior cervical discectomy and fusion for cervical radiculopathy and myelopathy , 1996 .

[29]  R. Fessler,et al.  Anterior cervical corpectomy for cervical spondylotic myelopathy. , 1998, Neurosurgery.

[30]  A. Reeves,et al.  Central corpectomy for cervical spondylotic myelopathy: a consecutive series with long-term follow-up evaluation. , 1991, Journal of neurosurgery.

[31]  V K Goel,et al.  Biomechanical comparison of anterior Caspar plate and three-level posterior fixation techniques in a human cadaveric model. , 1993, Journal of neurosurgery.

[32]  J. Turner,et al.  Natural History and Prognosis of Cervical Spondylosis , 1963, British medical journal.

[33]  M. Aebi,et al.  Treatment of Cervical Spine Injuries with Anterior Plating: Indications, Techniques, and Results , 1991, Spine.

[34]  Noshir A. Langrana,et al.  A Biomechanical Study of a Cervical Spine Stabilization Device: Roy‐Camille Plates , 1997, Spine.

[35]  B. J. Doherty,et al.  An in-vitro biomechanical comparison of the Orosco and AO locking plates for anterior cervical spine fixation. , 1995, Journal of spinal disorders.

[36]  T A Zdeblick,et al.  Quantitative Histologic Study of the Influence of Anterior Spinal Instrumentation and Biodegradable Polymer on Lumbar Interbody Fusion After Corpectomy; A Canine Model , 1992, Spine.

[37]  P. K. Robinson,et al.  Cervical myelopathy: a complication of cervical spondylosis. , 1956, Brain : a journal of neurology.

[38]  P. Cherubino,et al.  Multiple Subtotal Somatectomy: Technique and Evaluation of a Series of 39 Cases , 1984, Spine.

[39]  T. Whitecloud,et al.  Postlaminectomy kyphosis. Causes and surgical management. , 1992, The Orthopedic clinics of North America.

[40]  R. Brower,et al.  Cervical spondylotic myelopathy. Clinical syndrome and natural history. , 1992, The Orthopedic clinics of North America.

[41]  V. Sonntag,et al.  Cervical corpectomy and plate fixation for postlaminectomy kyphosis. , 1994, Journal of neurosurgery.

[42]  S. Nurjck.  The pathogenesis of the spinal cord disorder associated with cervical spondylosis. , 1972 .

[43]  S. Oka,et al.  Treatment of cervical spondylotic myelopathy by enlargement of the spinal canal anteriorly, followed by arthrodesis. , 1991, The Journal of bone and joint surgery. American volume.

[44]  D. D. Anderson,et al.  Biomechanical Evaluation of Cervical Spine Stabilization Methods Using a Porcine Model , 1995, Spine.

[45]  B. Cunningham,et al.  Biomechanical Analysis of Cervical Stabilization Systems: An Assessment of Transpedicular Screw Fixation in the Cervical Spine , 1994, Spine.

[46]  B. Cunningham,et al.  1989 Volvo Award in Basic Science: Device-Related Osteoporosis with Spinal Instrumentation , 1989, Spine.

[47]  B L Currier,et al.  Biomechanical Evaluation of Posterior Cervical Stabilization After a Wide Laminectomy , 1997, Spine.

[48]  E. Lysell.  Motion in the cervical spine. An experimental study on autopsy specimens. , 1969, Acta orthopaedica Scandinavica.

[49]  K. Yonenobu,et al.  Causes of Neurologic Deterioration Following Surgical Treatment of Cervical Myelopathy , 1986, Spine.

[50]  K. Shichikawa,et al.  Operations for cervical spondylotic myelopathy. A comparison of the results of anterior and posterior procedures. , 1985, The Journal of bone and joint surgery. British volume.

[51]  S. L. Griffith,et al.  Biomechanical comparison of anterior instrumentation for the cervical spine. , 1995, Journal of spinal disorders.

[52]  C. Dickman,et al.  Radiographic and clinical follow-up review of Caspar plates in 49 patients. , 1996, Journal of neurosurgery.

[53]  H. Larocca.  Cervical Spondylotic Myelopathy: Natural History , 1988, Spine.

[54]  B. Bose,et al.  Anterior cervical fusion using Caspar plating: analysis of results and review of the literature. , 1998, Surgical neurology.

[55]  A. Nordwall,et al.  Normal range of motion of the cervical spine. , 1989, Archives of physical medicine and rehabilitation.

[56]  M. Cabanela,et al.  Anterior Plate Stabilization for Bursting Teardrop Fractures of the Cervical Spine , 1988, Spine.

[57]  M M Panjabi,et al.  The Basic Kinematics of the Human Spine: A Review of Past and Current Knowledge , 1978, Spine.

[58]  A. White,et al.  Cervical spondylotic myelopathy. , 1993, The Journal of bone and joint surgery. American volume.

[59]  A. White,et al.  Evaluation and management of cervical spondylotic myelopathy. , 1994, Instructional course lectures.

[60]  H. Larocca,et al.  Fusion Rates in Multilevel Cervical Spondylosis Comparing Allograft Fibula with Autograft Fibula in 126 Patients , 1991, Spine.

[61]  P. Connolly,et al.  Anterior cervical fusion: outcome analysis of patients fused with and without anterior cervical plates. , 1996, Journal of spinal disorders.

[62]  T. Ducker,et al.  Trends and complications in cervical spine surgery: 1989-1993. , 1997, Journal of spinal disorders.

[63]  M. Schendel,et al.  Biomechanical Analysis of Facet and Graft Loading in a Smith‐Robinson Type Cervical Spine Model , 1994, Spine.

[64]  N Yoganandan,et al.  Biomechanical Alterations Induced by Multilevel Cervical Laminectomy , 1995, Spine.

[65]  V K Goel,et al.  Biomechanical evaluation of Caspar and Cervical Spine Locking Plate systems in a cadaveric model. , 1996, Journal of neurosurgery.

[66]  J Dvorak,et al.  The Effectiveness of Various Cervical Orthoses: An In Vivo Comparison of the Mechanical Stability Provided by Several Widely Used Models , 1996, Spine.

[67]  P. McAfee,et al.  Anterior spinal fixation after lumbar corpectomy. A study in dogs. , 1991, The Journal of bone and joint surgery. American volume.

[68]  K. Gill,et al.  Posterior Plating of the Cervical Spine: A Biomechanical Comparison of Different Posterior Fusion Techniques , 1988, Spine.

[69]  P. McAfee,et al.  Biomechanical Evaluation of Cervical Spinal Stabilization Methods in a Human Cadaveric Model , 1989, Spine.

[70]  A Rohlmann,et al.  A spinal fixation device for in vivo load measurement. , 1994, Journal of biomechanics.

[71]  D R Benson,et al.  Biomechanics of Cervical Spine Internal Fixation , 1991, Spine.

[72]  K. Yonenobu,et al.  Laminoplasty Versus Subtotal Corpectomy| A Comparative Study of Results in Multisegmental Cervical Spondylotic Myelopathy , 1992, Spine.

[73]  M. Carol,et al.  Cervical spondylitic myelopathies: surgical treatment. , 1988, Journal of spinal disorders.

[74]  V. Goel,et al.  An in-vitro study of the kinematics of the normal, injured and stabilized cervical spine. , 1984, Journal of biomechanics.

[75]  S. Nurick.  The natural history and the results of surgical treatment of the spinal cord disorder associated with cervical spondylosis. , 1972, Brain : a journal of neurology.

[76]  A. Vaccaro,et al.  Early failure of long segment anterior cervical plate fixation. , 1998, Journal of spinal disorders.

[77]  J. Taha,et al.  Osteosynthesis of the cervical spine with an anterior plate. , 1995, Orthopedics.

[78]  V. Goel,et al.  Kinematics of the Cervical Spine Following Discectomy and Stabilization , 1989, Spine.