Fatigue Performance of Cortical Bone Trajectory Screw Compared With Standard Trajectory Pedicle Screw

Akpolat, Yusuf T.; İnceoğlu, Serkan; Kinne, Nolan; Hunt, Devon; Cheng, Wayne K.

doi:10.1097/brs.0000000000001233

Cited by 56 publications

(35 citation statements)

References 6 publications

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“…[41] reported equivalent mechanical xation properties of both approaches in their cadaveric biomechanical study including pull-out and toggling testing. Contrary results were achieved by Akpolat et al [1], who stated that non-augmented TT screws had a better fatigue performance compared to CBT screws in vertebrae of compromised bone quality. As the use of bone cement during posterior instrumentation of the osteoporotic spine represents the gold standard, augmented TT screws were compared to possible alternatives within this study.…”

Section: Discussionmentioning

confidence: 71%

Comparison of Three Different Screw Trajectories in Osteoporotic Vertebrae: A Biomechanical Investigation

Jarvers

Schleifenbaum

Pfeifle³

et al. 2020

Preprint

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Background: Pedicle screw insertion in osteoporotic patients is challenging. Achieving more screw-cortical bone purchase and invasiveness minimization, the cortical bone trajectory and the midline cortical techniques represent alternatives to traditional pedicle screws. This study compares the fatigue behavior and fixation strength of the cement-augmented traditional trajectory (TT), the cortical bone trajectory (CBT) and the midline cortical (MC). Methods: Ten human cadaveric spine specimens (L1 - L5) were examined. The average age was 86.3 ± 7.2 years. CT scans were provided for preoperative planning. CBT and MC were implanted by using the patient-specific 3D-printed placement guide (MySpine®, Medacta International), TT were implanted freehand. All 10 cadaveric specimens were randomized to group A (CBT vs. MC) or group B (MC vs. TT). Each screw was loaded for 10,000 cycles. The failure criterion was doubling of the initial screw displacement resulting from the compressive force (60 N) at the first cycle, the stop criterion as a doubling of the initial screw displacement. After dynamic testing, screws were pulled out axially at 5 mm/min to determine their remaining fixation strength. Results: The mean pull-out forces did not differ significantly. Concerning the fatigue performance, only one out of ten MC of group A failed prematurely due to loosening after 1,500 cycles (L3). Five CBT already loosened during the first 500 cycles. The mean displacement was always lower in the MC. In group B, all TT showed no signs of failure or loosening. Three MC failed already after 26 cycles, 1,510 cycles, and 2,144 cycles, respectively. The TT showed always a lower mean displacement. In the subsequent pull-out tests, the remaining mean fixation strength of the MC (449.6 ± 298.9 N) was slightly higher compared to the mean pull-out force of the CBT (401.2 ± 261.4 N). However, MC (714.5 ± 488.0 N) were inferior to TT (990.2 ± 451.9 N).Conclusion: The current study demonstrated that cement-augmented TT have best fatigue and pull-out characteristics in osteoporotic lumbar vertebrae, followed by the MC and CBT. MC represent a promising alternative in osteoporotic bone if cement augmentation should be avoided. Using the patient-specific guide contributes to improve screws’ biomechanical properties.

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Section: Discussionmentioning

confidence: 71%

Comparison of Three Different Screw Trajectories in Osteoporotic Vertebrae: A Biomechanical Investigation

Jarvers

Schleifenbaum

Pfeifle³

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…These authors determined, in a multiple regression analysis, that BMD of the femoral neck, screw length within the lamina, and cephalad angle were significant independent factors affecting the torque [ 21 22 ]. However, in contradiction to previous articles, Akpolat et al [ 23 ] published in 2016 the results of a cadaveric study which concluded that implantation via TT required more cycles for screw loosening and showed better resistance to pullout. Finally, Sansur et al [ 24 ] compared CBT and TT in destabilized cadaveric lumbar spines with osteoporosis, showing that CBT gave better results in the lower spine because of an increase in cancellous bone limit fixation with TT ( Table 2 ) [ 3 14 15 16 17 18 19 21 22 23 24 25 26 ].…”

Section: Resultsmentioning

confidence: 86%

Review of Cortical Bone Trajectory: Evidence of a New Technique

et al. 2017

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This article summarizes recent evidence on the cortical bone trajectory (CBT) obtained from published anatomical, biomechanical, and clinical studies. CBT was proposed by Santoni in 2009 as a new trajectory that can improve the fixation of pedicle screws in response to screw loosening in osteoporotic patients. Recently, research interest has been growing with increasing numbers of published series and frequent reports of new applications. We performed an online database search using the terms “cortical bone trajectory,” “pedicle screw,” “CBT spine,” “CBT fixation,” “MISS CBT,” and “traditional trajectory.” The search included the PubMed, Ovid MEDLINE, Cochrane, and Google Scholar databases, resulting in an analysis of 42 articles in total. These covered three aspects of CBT research: anatomical studies, biomechanical parameters, and clinical cases or series. Compared to the traditional trajectory, CBT improves pullout strength, provides greater stiffness in cephalocaudal and mediolateral loading, and shows superior resistance to flexion/extension; however, it is inferior in lateral bending and axial rotation. CBT seems to provide better immediate implant stability. In clinical studies, CBT has shown better perioperative results for blood loss, length of stay in hospital, and surgery time; similar or better clinical postoperative scores; and similar comorbidity, without any major fixation system complications due to instrumentation failure or screw misplacement. In addition, advantages such as less lateral exposure allow it to be used as a minimally invasive technique. However, most of the clinical studies were retrospective case series or case-control studies; prospective evidence on this technique is scarce, making a definitive comparison with the traditional trajectory difficult. Nevertheless, we can conclude that CBT is a safe technique that offers good clinical results with similar biomechanical and perioperative parameters to those of the traditional trajectory. In addition, new applications can improve its results and make it useful for additional pathologies.

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“…11 The relationship with osteoporosis and cortical bone purchase requires further cautious investigation as well. 15 Our biomechanical study included the lumbar spine. Segmentspecific individual anatomical variance and sagittal curvature in respect to gravity could provide a unique vector environment that may affect the long-term stability of the spondylodesis.…”

Section: Discussionmentioning

confidence: 99%

Fixation Strength of Pedicle and Cortical Lumbar Vertebral Screws after Laminectomy: A Cadaver Study

Kwak

Shin

Cho

et al. 2018

J Neurol Surg A Cent Eur Neurosurg

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Fatigue Performance of Cortical Bone Trajectory Screw Compared With Standard Trajectory Pedicle Screw

Cited by 56 publications

References 6 publications

Comparison of Three Different Screw Trajectories in Osteoporotic Vertebrae: A Biomechanical Investigation

Comparison of Three Different Screw Trajectories in Osteoporotic Vertebrae: A Biomechanical Investigation

Review of Cortical Bone Trajectory: Evidence of a New Technique

Fixation Strength of Pedicle and Cortical Lumbar Vertebral Screws after Laminectomy: A Cadaver Study

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