Biomechanical insights into anterolateral vertebral screw fixation in osteoporotic spines: a comparative study of fixation methods and positions using porcine vertebrae
Abstract Objective Combining oblique lumbar interbody fusion (OLIF) with posterior pedicle screw fixation (PPSF) has been proposed to reduce cage subsidence, especially in osteoporotic spines. Recently, anterolateral screw-rod fixation has gained interest as it allows direct pathology observation an...
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BMC
2025-01-01
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| Series: | Journal of Orthopaedic Surgery and Research |
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| Online Access: | https://doi.org/10.1186/s13018-025-05452-5 |
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| author | Ming-Kai Hsieh Yun-Da Li Weng-Pin Chen De-Mei Lee Ching-Lung Tai |
| author_facet | Ming-Kai Hsieh Yun-Da Li Weng-Pin Chen De-Mei Lee Ching-Lung Tai |
| author_sort | Ming-Kai Hsieh |
| collection | DOAJ |
| description | Abstract Objective Combining oblique lumbar interbody fusion (OLIF) with posterior pedicle screw fixation (PPSF) has been proposed to reduce cage subsidence, especially in osteoporotic spines. Recently, anterolateral screw-rod fixation has gained interest as it allows direct pathology observation and avoids a posterior approach. However, controversies exist between anterolateral screw fixation systems and traditional PPSF due to variations in osteoporotic vertebral mineral density, screw fixation positions, and fixation methods (bicortical vs. unicortical). This study aimed to investigate the biomechanical impact of fixation position and method in osteoporotic spine. Methods Seventy-two fresh‑frozen porcine vertebrae (L1–6) were decalcified using 0.5 M EDTA and divided into two groups based on fixation method: bicortical or unicortical. Six groups for each method were created according to the screw position in the lateral vertebral body, with six specimens in each group: anterior, central, and posterior in the middle body and para-endplate regions. Correlations among screw position, fixation method and axial pullout strength were analyzed. Results A 4-week decalcification process, bone mineral density in the porcine vertebrae decreased to approximately 48% (p < 0.05) of the original value, categorizing them as osteoporotic. Bicortical fixation showed significantly greater pullout forces than unicortical fixation, with differences ranging from 82 to 273%. Notably, central or posterior screws outperformed anterior screws in pullout strength. Conclusion Bicortical fixation exhibited significantly greater pullout forces than unicortical fixation. We suggest positioning screws in the central or posterior region of the middle body with bicortical fixation in osteoporotic vertebrae. |
| format | Article |
| id | doaj-art-888b0ebc3a884fe992eff6df346fd60c |
| institution | Kabale University |
| issn | 1749-799X |
| language | English |
| publishDate | 2025-01-01 |
| publisher | BMC |
| record_format | Article |
| series | Journal of Orthopaedic Surgery and Research |
| spelling | doaj-art-888b0ebc3a884fe992eff6df346fd60c2025-01-12T12:32:35ZengBMCJournal of Orthopaedic Surgery and Research1749-799X2025-01-0120111410.1186/s13018-025-05452-5Biomechanical insights into anterolateral vertebral screw fixation in osteoporotic spines: a comparative study of fixation methods and positions using porcine vertebraeMing-Kai Hsieh0Yun-Da Li1Weng-Pin Chen2De-Mei Lee3Ching-Lung Tai4Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital, Chang Gung University College of MedicineDepartment of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital, Chang Gung University College of MedicineDepartment of Mechanical Engineering, National Taipei University of TechnologyDepartment of Mechanical Engineering, Chang Gung UniversityDepartment of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital, Chang Gung University College of MedicineAbstract Objective Combining oblique lumbar interbody fusion (OLIF) with posterior pedicle screw fixation (PPSF) has been proposed to reduce cage subsidence, especially in osteoporotic spines. Recently, anterolateral screw-rod fixation has gained interest as it allows direct pathology observation and avoids a posterior approach. However, controversies exist between anterolateral screw fixation systems and traditional PPSF due to variations in osteoporotic vertebral mineral density, screw fixation positions, and fixation methods (bicortical vs. unicortical). This study aimed to investigate the biomechanical impact of fixation position and method in osteoporotic spine. Methods Seventy-two fresh‑frozen porcine vertebrae (L1–6) were decalcified using 0.5 M EDTA and divided into two groups based on fixation method: bicortical or unicortical. Six groups for each method were created according to the screw position in the lateral vertebral body, with six specimens in each group: anterior, central, and posterior in the middle body and para-endplate regions. Correlations among screw position, fixation method and axial pullout strength were analyzed. Results A 4-week decalcification process, bone mineral density in the porcine vertebrae decreased to approximately 48% (p < 0.05) of the original value, categorizing them as osteoporotic. Bicortical fixation showed significantly greater pullout forces than unicortical fixation, with differences ranging from 82 to 273%. Notably, central or posterior screws outperformed anterior screws in pullout strength. Conclusion Bicortical fixation exhibited significantly greater pullout forces than unicortical fixation. We suggest positioning screws in the central or posterior region of the middle body with bicortical fixation in osteoporotic vertebrae.https://doi.org/10.1186/s13018-025-05452-5Pedicle screwOsteoporosisAnterolateral vertebral screw fixationBicortical and unicortical screw fixationScrew pullout test |
| spellingShingle | Ming-Kai Hsieh Yun-Da Li Weng-Pin Chen De-Mei Lee Ching-Lung Tai Biomechanical insights into anterolateral vertebral screw fixation in osteoporotic spines: a comparative study of fixation methods and positions using porcine vertebrae Journal of Orthopaedic Surgery and Research Pedicle screw Osteoporosis Anterolateral vertebral screw fixation Bicortical and unicortical screw fixation Screw pullout test |
| title | Biomechanical insights into anterolateral vertebral screw fixation in osteoporotic spines: a comparative study of fixation methods and positions using porcine vertebrae |
| title_full | Biomechanical insights into anterolateral vertebral screw fixation in osteoporotic spines: a comparative study of fixation methods and positions using porcine vertebrae |
| title_fullStr | Biomechanical insights into anterolateral vertebral screw fixation in osteoporotic spines: a comparative study of fixation methods and positions using porcine vertebrae |
| title_full_unstemmed | Biomechanical insights into anterolateral vertebral screw fixation in osteoporotic spines: a comparative study of fixation methods and positions using porcine vertebrae |
| title_short | Biomechanical insights into anterolateral vertebral screw fixation in osteoporotic spines: a comparative study of fixation methods and positions using porcine vertebrae |
| title_sort | biomechanical insights into anterolateral vertebral screw fixation in osteoporotic spines a comparative study of fixation methods and positions using porcine vertebrae |
| topic | Pedicle screw Osteoporosis Anterolateral vertebral screw fixation Bicortical and unicortical screw fixation Screw pullout test |
| url | https://doi.org/10.1186/s13018-025-05452-5 |
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