Comparative Study of Cortical Bone Trajectory-Pedicle Screw (Cortical Screw) Versus Conventional Pedicle Screw in Single-Level Posterior Lumbar Interbody Fusion: A 2-Year Post Hoc Analysis from Prospectively Randomized Data

Lee, Gun Woo; Ahn, Myun-Whan

doi:10.1016/j.wneu.2017.09.137

Cited by 37 publications

(58 citation statements)

References 36 publications

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“…The criterion for controlling the values of entire lumbosacral motion was adapted as a reasonable approach to evaluate implant-induced effects on the adjacent segments. 11,14,15 The applied displacement onto the L1 vertebra ensured the disc ROMs of the adjacent, transition, and fixation segments of the healthy model comparable to the cadaveric data obtained from the study by Yamamoto et al 23 The disk ROM was defined as the difference between disk angles before and after lumbar motion. The nonlinear algorithm with a large-deformation formula and direct-sparse solver was used in the software Simulation Ed.…”

Section: Finite Element Analyses and Validationmentioning

confidence: 92%

“…[11][12][13] The decrease in postoperative bed-time was attributed to the smaller incision size, decreased disruption of muscle attachment, and soft-tissue dissection using CBT. 14 Varieties of spinal dynamic fixators have been used such as Cosmic or Dynesys systems (pedicle screw implants) and DIAM and Corflex (interspinous process implant). Among them, the Dynesys system is the most widely-used dynamic fixator that prevents adjacent segment disease (ASD) progression and provides support for fusion surgery.…”

Section: Introductionmentioning

confidence: 99%

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Biomechanical Investigation about Traditional and Cortical Trajectory Screws of Static and Dynamic Lumbar Fixation

Liu

Wang

et al. 2020

Preprint

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Background To evaluate kinetic and kinematic behavior in both static and dynamic CBT fixation a finite element study was designed. Two types of screw trajectories are commonly used in lumbar surgery. Both traditional trajectory (TT) and cortical bone trajectory (CBT) provide equivalent pull-out strengths of a screw. Dynesys fixation of TT screws, but not dynamization of CBT screws, has been used extensively in lumbar surgery. This study aimed to simulate the biomechanics of CBT-based dynamic system for an evaluation of CBT dynamization. Methods A validated nonlinearly lumbosacral finite-element model was used to simulate four variations of screw fixation. Responses of both implant (screw stress) and tissues (disc motion, disc stress, and facet force) at the upper adjacent (L3-L4) and fixed (L4-L5) segments were used as the evaluation indices. Flexion, extension, bending, and rotation of both TT and CBT screws were simulated in this study for comparison. Results The results showed that the TT static was the most effective stabilizer to the L4-L5 segment, followed by CBT static, TT dynamic, and the CBT dynamic, which was the least effective. Dynamization of the TT and CBT fixators decreased stability of the fixed segment and alleviate adjacent segment stress compensation. The 3.5-mm diameter CBT screw deteriorated stress distribution and rendered it vulnerable to bone-screw loosening and fatigue cracking. Conclusions A systematic analysis of the effects of TT and CBT fixation constructs on kinematic and kinetic responses in a full lumbosacral model is currently lacking. This study examined both the static fixation effect and its dynamic counterpart and identified that dynamization of CBT have slightly inferior structural stiffness than dynamic TT and cautious preoperative evaluation is essential if 3.5-mm diameter CBT screws are used. Therefore, 4.5-mm or 5.5-mm diameter CBT screws, or as big as tolerated, are recommended to avoid loosening and cracking.

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Section: Finite Element Analyses and Validationmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Biomechanical Investigation about Traditional and Cortical Trajectory Screws of Static and Dynamic Lumbar Fixation

Liu

Wang

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…The criterion for controlling the values of entire lumbosacral motion was adapted as a reasonable approach to evaluate implant-induced effects on the adjacent segments. 11,14,15 The applied displacement onto the L1 vertebra ensured the disc ROMs of the adjacent, transition, and xation segments of the healthy model comparable to the cadaveric data obtained from the study by Yamamoto et al 23 The disk ROM was de ned as the difference between disk angles before and after lumbar motion. The nonlinear algorithm with a large-deformation formula and direct-sparse solver was used in the software Simulation Ed.…”

Section: Finite Element Analyses and Validationmentioning

confidence: 97%

“…[11][12][13] The decrease in postoperative bed-time was attributed to the smaller incision size, decreased disruption of muscle attachment, and softtissue dissection using CBT. 14…”

Section: Introductionmentioning

confidence: 99%

Traditional and Cortical Trajectory Screws of Static and Dynamic Lumbar Fixation- A Finite Element Study

Liu

Wang

et al. 2020

Preprint

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Background: Two types of screw trajectories are commonly used in lumbar surgery. Both traditional trajectory (TT) and cortical bone trajectory (CBT) were shown to provide equivalent pull-out strengths of a screw. CBT utilizing a laterally-directed trajectory engaging only cortical bone in the pedicle is widely used in minimal invasive spine posterior fusion surgery. It has been demonstrated that CBT exerts a lower likelihood of violating the facet joint, and superior pull-out strength than the TT screws, especially in osteoporotic vertebral body. No design yet to apply this trajectory to dynamic fixation. To evaluate kinetic and kinematic behavior in both static and dynamic CBT fixation a finite element study was designed. This study aimed to simulate the biomechanics of CBT-based dynamic system for an evaluation of CBT dynamization. Methods: A validated nonlinearly lumbosacral finite-element model was used to simulate four variations of screw fixation. Responses of both implant (screw stress) and tissues (disc motion, disc stress, and facet force) at the upper adjacent (L3-L4) and fixed (L4-L5) segments were used as the evaluation indices. Flexion, extension, bending, and rotation of both TT and CBT screws were simulated in this study for comparison. Results: The results showed that the TT static was the most effective stabilizer to the L4-L5 segment, followed by CBT static, TT dynamic, and the CBT dynamic, which was the least effective. Dynamization of the TT and CBT fixators decreased stability of the fixed segment and alleviate adjacent segment stress compensation. The 3.5-mm diameter CBT screw deteriorated stress distribution and rendered it vulnerable to bone-screw loosening and fatigue cracking. Conclusions: Modeling the effects of TT and CBT fixation in a full lumbosacral model suggest that dynamic TT provide slightly superior stability compared with dynamic CBT especially in bending and rotation. In dynamic CBT design, large diameter screws might avoid issues with loosening and cracking.

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“…We feel that CBT screws and rods may not show superior correction potential for spinal sagittal alignment. [21] conducted a comparative study of CBT vs. TPS in single level PLIF, and reported that the fusion rate and clinical outcomes were similar between the two groups. Keorochana et al [22] conducted a systematic review and meta-analysis based on eight studies to compare the outcomes of CBT and TPS in lumbar spinal fusion and found that CBT was comparable to TPS in terms of the clinical outcomes and fusion rates, but offered a lower incidence of complications and caused less trauma.…”

Section: Clinicians Have Developed Various Surgical Techniques To Deamentioning

confidence: 99%

Extended interbody fusion using cortical bone trajectory screws vs. traditional pedicle screws in the treatment of adjacent segment disease after transforaminal lumbar interbody fusion with pedicle screws: a retrospective case control study

Song¹,

Ren²,

Han³

et al. 2020

Preprint

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Background To present two minimally invasive surgical techniques using cortical bone trajectory screws with posterior lumbar interbody fusion (CBT-PLIF) and traditional pedicle screws and a domino system with transforaminal lumbar interbody fusion (TPS-Domino-TLIF) for adjacent segment disease (ASD) after lumbar fusion surgery, and compare the postoperative radiographic and clinical outcomes between the two techniques for ASD. Methods Of the 36 patients included in this study, 16 patients received CBT-PLIF and the other 20 patients received TPS-Domino-TLIF. Patient demographics, surgical data, complications, radiologic and clinical outcomes were evaluated and compared between the two groups. Results The surgical duration of TPS-Domino-TLIF was significantly shorter than that of CBT-PLIF (p < 0.001). There was less estimated blood loss (EBL) and a lower frequency of intra-operative fluoroscopy in TPS-Domino-TLIF as compared with CBT-PLIF (p < 0.001). The lumbar lordotic angle was improved both at immediate post-operation (p = 0.006) and the last follow-up (p = 0.007) in TPS-Domino-TLIF group as compared with CBT-PLIF group. The mean inter-vertebral height in TPS-Domino-TLIF group was significantly larger than that in CBT-PLIF group at immediate post-operation (p = 0.007) and the last follow-up (p = 0.005). The clinical outcomes in terms of the mean VAS-back, VAS-leg and ODI were improved significantly postoperatively in both groups. Conclusions As a more minimally invasive surgical technique for ASD, TPS-Domino-TLIF could be considered a viable alternative to the midline fusion technique using CBT.

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Comparative Study of Cortical Bone Trajectory-Pedicle Screw (Cortical Screw) Versus Conventional Pedicle Screw in Single-Level Posterior Lumbar Interbody Fusion: A 2-Year Post Hoc Analysis from Prospectively Randomized Data

Cited by 37 publications

References 36 publications

Biomechanical Investigation about Traditional and Cortical Trajectory Screws of Static and Dynamic Lumbar Fixation

Biomechanical Investigation about Traditional and Cortical Trajectory Screws of Static and Dynamic Lumbar Fixation

Traditional and Cortical Trajectory Screws of Static and Dynamic Lumbar Fixation- A Finite Element Study

Extended interbody fusion using cortical bone trajectory screws vs. traditional pedicle screws in the treatment of adjacent segment disease after transforaminal lumbar interbody fusion with pedicle screws: a retrospective case control study

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