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"Pendahuluan: Instrumentasi posterior mengharuskan dipertahankannya fiksasi stabil sekrup pedikel di tulang belakang untuk mencapai fusi. Hal ini dapat menjadi sulit terutama pada kondisi tertentu, misalnya pada penurunan densitas masa tulang pedikel. Teknik insersi sekrup dengan lintasan kortikal diharapkan menambah antarmuka sekrup dan tulang dengan meningkatkan engagement antara sekrup dengan korteks tulang. Lintasan sekrup dari arah kortikal infero-superior serta kortikal supero-inferior diharapkan memiliki keunggulan kekuatan cabut (pullout strength) dibandingkan dengan lintasan konvensional dalam mengatasi masalah ini. Penelitian ini bertujuan untuk mendapatkan profil biomekanik awal lintasan kortikal dan perbedaan pull out strength lintasan konvensional (Weinstein, 1992), kortikal infero-superior (Santoni, 2009), dan kortikal supero-inferior. Metode: Sampel dari lumbal (L1-L5) babi Yorkshire (n=30) dilakukan pengukuran morfometri dan dibagi secara acak. Sampel dilakukan pengeboran dan sekrup dimasukkan ke dalam tulang dengan tiga lintasan: konvensional, kortikal infero-superior, dan kortikal supero-inferior. Arah lintasan diperiksa kembali dengan sinar-x. Dilakukan penarikan sekrup dengan arah sesuai aksis insersi sekrup dengan kecepatan translasi 5mm/menit. Hasil dicatat dengan satuan Newton (N). Hasil: Didapatkan rata-rata nilai uji tarik pada kelompok konvensional, infero-superior, dan supero-inferior masing-masing 491,72 (187.23) N, 822,16 (295.73) N, dan 644,14 (201.97) N. Lintasan kortikal infero-superior dan kortikal supero-inferior masing-masing mendapatkan nilai 67% dan 30% lebih tinggi dibandingkan dengan lintasan konvensional. Hasil uji ANOVA satu arah dan uji post-hoc Tukey menunjukkan perbedaan signifikan antara lintasan kortikal infero-superior dengan konvensional (p<0.01). Kesimpulan: Lintasan sekrup dalam tulang lumbal dapat memengaruhi nilai pullout sekrup. Keterlibatan tulang kortikal pada lintasan insersi sekrup baru ini bisa meningkatkan nilai pullout sekrup pedikel. Secara statistik pullout strength lintasan kortikal infero-superior dan kortikal supero-inferior tidak ada perbedaan. Studi ini menunjukkan nilai pullout yang lebih tinggi sebesar 30% dari lintasan yang disarankan peneliti dibandingkan dengan lintasan konvensional, walaupun tidak ada perbedaan signifikan secara statistik.

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Introduction: Posterior instrumentation is aimed to achieve spinal fusion which is helped by maintaining a stable pedicle screw insertion within the pedicle. This presents a challenge especially in conditions with low bone quality. Pedicle screw insertion with cortical bone trajectory is designed to add interface between the screw and the bone through engagement between pedicles and the cortex when compared to conventional pedicle screw insertion. Pedicle screw insertion trajectory from cortical infero-superior and the proposed cortical supero-inferior should obtain better pull out performance when compared with conventional pedicle trajectory. We aim to evaluate the pull out strength differences between conventional (Weinstein, 1992) pedicle screw trajectory, cortical infero-superior (Santoni, 2009), and a proposed cortical supero-inferior trajectory.

Methods: Samples from Yorkshire porcine lumbar spine (L1-L5) (n=30) were relieved of soft tissue attachments and dried. Morphometric measurements were conducted and the samples were randomly assigned to three groups. The screws were inserted into the vertebrae by drilling with the three trajectories: conventional, cortical infero-superior, and cortical supero-inferior. The trajectory of the screws were examined using x-rays. Pull-out tests were conducted by applying uniaxial traction in line with the screw trajectory with a translational speed of 5mm/minutes. The results of the pull-out are measured in Newton (N).

Results: We obtained a mean value of pullout force in conventional trajectory 491,72 (187.2) N, cortical infero-superior 822,16 (295.73) N, and cortical supero-inferior 644,14 (201.97) N. Cortical infero-superior trajectory and cortical supero-inferior trajectory attained 67% and 30% higher pullout mean respectively. Using one-way ANOVA and a post-hoc Tukey test revealed a significant difference between cortical infero-superior and conventional trajectory (p<0.01). Differing pull out strengths between cortical infero-superior and supero-inferior trajectory showed no statistical significance. Our study showed a 30% higher pull-out strength in our proposed trajectory compared with conventional trajectory although not statistically significant.

Conclusion: The trajectory of the screws within the lumbar spine seemed to have an impact in pullout strength. Cortical bone engagement using the novel trajectories may increase screw pullout strength of pedicle screws."

"ABSTRAKOBJECTIVE: We determined whether the accuracy of thoracaolumbar pedicle screwdirection placement is optimized with a technique using anatomic landmarks forpedicle screw and using S30 as guidance (Technique 1). This technique wascompared with a technique using anatomic landmarks for pedicle screw placementwithout S3D as guidance (Technique 2).METHODS: T7-L1 specimens were harvested from fresh human cadavers. Pediclescrew placement using technique 2 was performed on lelt side. Vertebral rotationand vertebral tilting measurement was determined using S3D. Then pedicle screwplacement using technique 1 was performed on right side. Axial dissections wereperformed on pedicular specimens. Deviation of the screws from the ideal entry pointor trajectory was analyzed to quantitatively compare the two techniques.RESULTS: Axial analysis of the specimens showed that all screw placements werewithin the pedicles. Scatter plot analysis demonstrated that screws placed usingTechnique 2 were more likely to have the combination of entry points andtrajectories medial to the ideal entry point and trajectory.CONCLUSION: All screw placements were grossly within the confines of thepedicles, regardless of technique, as evidenced by axial dissections analysis."

"Instrumentasi posterior mengharuskan dipertahankannya fiksasi stabil sekrup pedikel di tulang belakang untuk mencapai fusi. Hal ini dapat menjadi sulit terutama pada kondisi tertentu, misalnya pada penurunan densitas masa tulang pedikel. Teknik insersi sekrup dengan lintasan kortikal diharapkan menambah antarmuka sekrup dan tulang dengan meningkatkan engagement antara sekrup dengan korteks tulang. Lintasan sekrup dari arah kortikal infero-superior serta kortikal supero-inferior diharapkan memiliki keunggulan kekuatan cabut (pullout strength) dibandingkan dengan lintasan konvensional dalam mengatasi masalah ini. Penelitian ini bertujuan untuk mendapatkan profil biomekanik awal lintasan kortikal dan perbedaan pull out strength lintasan konvensional (Weinstein, 1992), kortikal infero-superior (Santoni, 2009), dan kortikal supero-inferior. Metode: Sampel dari lumbal (L1-L5) babi Yorkshire (n=30) dilakukan pengukuran morfometri dan dibagi secara acak. Sampel dilakukan pengeboran dan sekrup dimasukkan ke dalam tulang dengan tiga lintasan: konvensional, kortikal infero-superior, dan kortikal supero-inferior. Arah lintasan diperiksa kembali dengan sinar-x. Dilakukan penarikan sekrup dengan arah sesuai aksis insersi sekrup dengan kecepatan translasi 5mm/menit. Hasil dicatat dengan satuan Newton (N). Hasil: Didapatkan rata-rata nilai uji tarik pada kelompok konvensional, infero-superior, dan supero-inferior masing-masing 491,72 (187.23) N, 822,16 (295.73) N, dan 644,14 (201.97) N. Lintasan kortikal infero-superior dan kortikal supero-inferior masing-masing mendapatkan nilai 67% dan 30% lebih tinggi dibandingkan dengan lintasan konvensional. Hasil uji ANOVA satu arah dan uji post-hoc Tukey menunjukkan perbedaan signifikan antara lintasan kortikal infero-superior dengan konvensional (p<0.01). Kesimpulan: Lintasan sekrup dalam tulang lumbal dapat memengaruhi nilai pullout sekrup. Keterlibatan tulang kortikal pada lintasan insersi sekrup baru ini bisa meningkatkan nilai pullout sekrup pedikel. Secara statistik pullout strength lintasan kortikal infero-superior dan kortikal supero-inferior tidak ada perbedaan. Studi ini menunjukkan nilai pullout yang lebih tinggi sebesar 30% dari lintasan yang disarankan peneliti dibandingkan dengan lintasan konvensional, walaupun tidak ada perbedaan signifikan secara statistik.

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Introduction: Posterior instrumentation is aimed to achieve spinal fusion which is helped by maintaining a stable pedicle screw insertion within the pedicle. This presents a challenge especially in conditions with low bone quality. Pedicle screw insertion with cortical bone trajectory is designed to add interface between the screw and the bone through engagement between pedicles and the cortex when compared to conventional pedicle screw insertion. Pedicle screw insertion trajectory from cortical infero-superior and the proposed cortical supero-inferior should obtain better pull out performance when compared with conventional pedicle trajectory. We aim to evaluate the pull out strength differences between conventional (Weinstein, 1992) pedicle screw trajectory, cortical infero-superior (Santoni, 2009), and a proposed cortical supero-inferior trajectory. Methods: Samples from Yorkshire porcine lumbar spine (L1-L5) (n=30) were relieved of soft tissue attachments and dried. Morphometric measurements were conducted and the samples were randomly assigned to three groups. The screws were inserted into the vertebrae by drilling with the three trajectories: conventional, cortical infero-superior, and cortical supero-inferior. The trajectory of the screws were examined using x-rays. Pull-out tests were conducted by applying uniaxial traction in line with the screw trajectory with a translational speed of 5mm/minutes. The results of the pull-out are measured in Newton (N). Results: We obtained a mean value of pullout force in conventional trajectory 491,72 (187.2) N, cortical infero-superior 822,16 (295.73) N, and cortical supero-inferior 644,14 (201.97) N. Cortical infero-superior trajectory and cortical supero-inferior trajectory attained 67% and 30% higher pullout mean respectively. Using one-way ANOVA and a post-hoc Tukey test revealed a significant difference between cortical infero-superior and conventional trajectory (p<0.01). Differing pull out strengths between cortical infero-superior and supero-inferior trajectory showed no statistical significance. Our study showed a 30% higher pull-out strength in our proposed trajectory compared with conventional trajectory although not statistically significant. Conclusion: The trajectory of the screws within the lumbar spine seemed to have an impact in pullout strength. Cortical bone engagement using the novel trajectories may increase screw pullout strength of pedicle screws."

"Latar Belakang: Acetabuloplasty dengan bone graft merupakan salah satu tatalaksana adult congenital hip disease. Tindakan ini bertujuan memperbaiki defisiensi dinding acetabulum dan meningkatkan stabilitas implant. Namun, terdapat variasi dalam teknik, lokasi, dan jenis implant yang dapat dipasang. Oleh karena itu, penelitian ini bertujuan membandingkan kekuatan konstruksi acetabuloplasty dengan pelbagai screw pada teknik bone graft kepala femur. Metode: Model pelvis 3D dibuat dengan simulasi defek containment 30% pada sisi antero-superior acetabulum. Rekonstruksi acetabuloplasty dibuat tulang kepala femur berbentuk angka 7 difiksasi dengan screw, diikuti uji finite element untuk menilai distribusi stres. Konstruk acetabuloplasty diaplikasikan pada tiga kelompok uji: A (2 screw cannulated ukuran 6.5 mm), B (2 screw cortical ukuran 4.5 mm), C (1 screw cannulated 6.5 mm + 1 screw cortical 4.5 mm). Spesimen diberi beban dari 50 hingga 750 N dengan peningkatan sebesar 100 N/detik sebagai simulasi single leg stance. FGM pada beban 750 N diukur menggunakan kamera. Kemudian dilakukan uji load to failure. Hasil: Kelompok sampel cannulated ukuran 6.5 mm lebih unggul secara significant pada uji load to failure dengan titik patah 2 kali lipat lebih besar dibandingkan kelompok lainnya (2191 N v 1206 N v 1065 N; p<0.01). Uji loading dengan 750 Newton juga menunjukkan bahwa kelompok A unggul dengan rerata pergeseran, peregangan, dan tilting terkecil di semua posisi marking kecuali pada tilting marking posterior superior. Sampel cannulated ukuran 6.5mm juga memiliki titik yield dan titik kekuatan maksimum terbesar. Sementara itu, kelompok B dan C memiliki hasil uji yang serupa satu sama lain. Tetapi, temuan ini tidak bermakna secara statistik (p>0.05) Kesimpulan: Acetabuloplasty dengan bone graft adalah metode biomekanik yang aman untuk terapi definitif pada congenital adult hip disease. Pemilihan screw cannulated dengan ukuran diameter screw lebih besar memiliki keunggulan biomekanik bila dibandingkan dengan kelompok uji screw cortical maupun kombinasi antara kedua screw.

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Background: Acetabuloplasty using bone grafts is one of the treatment options for adult congenital hip disease. It aims to correct acetabular wall deficiencies and enhance pelvic implant stability. However, there are variations in the positions, types, and techniques of screw placements, leaving the fixation strength unknown. Therefore, this study aims to evaluate the structural strength of acetabuloplasty with screws in femoral head bone graft techniques. Methods: A 3D pelvis model was created to simulate a 30% containment defect on the antero-superior aspect of the acetabulum. Acetabuloplasty reconstruction utilized a femoral head bone graft shaped like a "7," which was fixed with screws, followed by finite element analysis to assess stress distribution. The acetabuloplasty construct was applied to three test groups: A (2 cannulated screws - 6.5 mm), B (2 cortical screws - 4.5 mm), and C (1 cannulated screw - 6.5 mm + 1 non-cannulated screw - 4.5 mm). Specimens were subjected to loads ranging from 50 to 750 N, with increments of 100 N/sec to simulate single-leg stance. FGM at 750 N were measured using a camera. Then the specimens were subjected to loading until implant failure. Results: Group A with cannulated 6.5 mm screws are shown to be significantly better in the load-to-failure test with a mean breaking point twice larger than the other two groups (2191 N v 1206 N v 1065 N; p<0.01). Group A also shows superior results in the single- leg stance in all marking positions with the smallest displacement, stretch, and tilting -bar the posterior superior tilt. Group A also has the largest yield and maximum strength point. In comparison, groups B and C had similarly inferior results. However, the findings are statistically insignificant (p>0.05). Conclusion: Acetabuloplasty with bone graft is a biomechanically safe method for definitive treatment of adult congenital hip disease. Larger cannulated screws are shown to have a biomechanical advantage compared to cortical smaller screws or a combination of both screws."