Is Cervical Sagittal Imbalance a Risk Factor for Adjacent Segment Pathomechanics After Multilevel Fusion?
| Autor: | William R. Sears, Gerard Carandang, Alexander J. Ghanayem, Saeed Khayatzadeh, Laurie M Lomasney, Muturi Muriuki, Zachary A. Smith, Leonard I. Voronov, Avinash G. Patwardhan, Ngoc Lam Nguyen, Robert M. Havey |
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| Rok vydání: | 2015 |
| Předmět: |
Adult
Male medicine.medical_treatment Radiography Surgical planning 03 medical and health sciences Young Adult 0302 clinical medicine Risk Factors medicine Humans Orthopedics and Sports Medicine Range of Motion Articular Postural Balance Aged 030222 orthopedics business.industry Biomechanics Anatomy Middle Aged Sagittal plane Biomechanical Phenomena medicine.anatomical_structure Spinal Fusion Spinal fusion Cervical Vertebrae Female Neurology (clinical) business Cadaveric spasm Range of motion 030217 neurology & neurosurgery Cervical vertebrae |
| Zdroj: | Spine. 41(10) |
| ISSN: | 1528-1159 |
| Popis: | STUDY DESIGN A biomechanical study using human spine specimens. OBJECTIVE The aim of this study was to assess whether the presence of cervical sagittal imbalance is an independent risk factor for increasing the mechanical burden on discs adjacent to cervical multilevel fusions. SUMMARY OF BACKGROUND DATA The horizontal offset distance between the C2 plumbline and C7 vertebral body (C2-C7 Sagittal Vertical Axis (SVA)) or the angle made with vertical by a line connecting the C2 and C7 vertebral bodies (C2-C7 tilt angle) are used as radiographic measures to assess cervical sagittal balance. There is level III clinical evidence that sagittal imbalance caused by kyphotic fusions or global spinal sagittal malalignment may increase the risk of adjacent segment pathology. METHODS Thirteen human cadaveric cervical spines (Occiput-T1; age: 50.6 years; range: 21-67) were tested first in the native intact state and then after instrumentation across C4-C6 to simulate in situ two-level fusion. Specimens were tested using a previously validated experimental model that allowed measurement of spinal response to prescribed imbalance. The effects of fusion on segmental angular alignments and intradiscal pressures in the C3-C4 and C6-C7 discs, above and below the fusion, were evaluated at different magnitudes of C2-C7 tilt angle (or C2-C7 SVA). RESULTS When compared with the pre-fusion state, in situ fusion across C4-C6 segments required increased flexion angulation and resulted in increased intradiscal pressure at the C6-C7 disc below the fusion in order to accommodate the same increase in C2-C7 tilt angle or C2-C7 SVA (P |
| Databáze: | OpenAIRE |
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