Effect of augmentation techniques on the failure of pedicle screws under cranio-caudal cyclic loading

Bostelmann, Richard; Keiler, Alexander; Steiger, Hans Jakob; Scholz, A; Cornelius, Jan Frédérick; Schmoelz, Werner

doi:10.1007/s00586-015-3904-3

Cited by 67 publications

(62 citation statements)

References 27 publications

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“…For conventional pedicle screws, various augmentation techniques and augmentation materials to prevent screw loosening are available [16]. So far, the augmentation of pedicle screws with PMMA has demonstrated to be the most efficient solution to enhance screw strength in osteoporotic bone [2][3][4][5][6][7]. It has shown clinical efficacy in the management of degenerative disease [17] and fractures [18][19][20].…”

Section: Discussionmentioning

confidence: 99%

“…Osseous resistance, loading and in vivo loading of structures can only be approximated. This study's strengths are that its findings underline for the first time, that the time of cement application has an effect on pedicle screw anchorage in the osteoporotic vertebral body under physiologic related cyclic craniocaudal loading [2,[25][26][27][28][29] and it applies a stepwise increasing load protocol designed to investigate implant anchorage in reduced bone quality [30,31].…”

Section: Discussionmentioning

confidence: 99%

“…3). The loading rod was connected to the pedicle screw with a lever arm of 15 mm to the rotational axis [2]. A 3D motion analysis system (Zebris, Winbiomechanics, Isny, Germany) was mounted to the screw head and the x-y bearing table.…”

Section: Reposition Maneuvermentioning

confidence: 99%

“…Cyclic loading was terminated after 10 mm of machine actuator displacement relative to the unloaded starting point. For post testing data analysis, the failure criteria were defined as an absolute angular tilt of more than 8°or an angle amplitude increase of more than 1°within 100 cycles [2]. Per cycle motion of the screw within the vertebral body was evaluated after 1000, 2000, and 3000 cycles.…”

Section: Reposition Maneuvermentioning

confidence: 99%

“…Pedicle screw augmentation with polymethylmethacrylate (PMMA) cement enhances initial fixation or resistance to loosening under dynamic loading conditions of the screws in osteoporotic bone [2][3][4][5][6][7]. However, the ideal timing for augmentation when a reposition maneuver is necessary, such as in fractures or deformities, is still controversially discussed.…”

Section: Introductionmentioning

confidence: 99%

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Timing of PMMA cement application for pedicle screw augmentation affects screw anchorage

et al. 2017

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Introduction Cement augmentation is an established method to increase the pedicle screw (PS) anchorage in osteoporotic vertebral bodies. The ideal timing for augmentation when a reposition maneuver is necessary is controversial. While augmentation of the PS before reposition maneuver may increase the force applied it on the vertebrae, it bears the risk to impair PS anchorage, whereas augmenting the PS after the maneuver may restore this anchorage and prevent early screw loosening. The purpose of the present study was to evaluate the effect of cement application timing on PS anchorage in the osteoporotic vertebral body. Methods Ten lumbar vertebrae (L1-L5) were used for testing. The left and right pedicles of each vertebra were instrumented with the same PS size and used for pairwise comparison of the two timing points for augmentation. For the reposition maneuver, the left PS was loaded axially under displacement control (2 9 ±2 mm, 3 9 ±6 mm, 3 9 ±10 mm) to simulate a reposition maneuver.Subsequently, both PS were augmented with 2 ml PMMA cement. The same force as measured during the left PS maneuver was applied to the previously augmented right hand side PS [2 9 F (±2 mm), 3 9 F (±6 mm), 3 9 F (±10 mm)]. Both PS were cyclically loaded with initial forces of ?50 and -50 N, while the lower force was increased by 5 N every 100 cycles until total failure of the PS. The PS motion was measured with a 3D motion analysis system. After cyclic loading stress, X-rays were taken to identify the PS loosening mechanism. Results In comparison with PS augmented prior to the reposition maneuver, PS augmented after the reposition maneuver showed a significant higher number of load cycles until failure (5930 ± 1899 vs 3830 ± 1706, p = 0.015). The predominant loosening mechanism for PS augmented after the reposition maneuver was PS toggling with the attached cement cloud within the trabecular bone. While PS augmented prior to the reposition, maneuver showed a motion of the screw within the cement cloud. Conclusion The time of cement application has an effect on PS anchorage in the osteoporotic vertebral body if a reposition maneuver of the instrumented vertebrae is carried out. PS augmented after the reposition maneuver showed a significant higher number of load cycles until screw loosening.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Reposition Maneuvermentioning

confidence: 99%

Section: Reposition Maneuvermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Timing of PMMA cement application for pedicle screw augmentation affects screw anchorage

et al. 2017

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Increased stability due to symmetric cement volume in augmented pedicle screws? A biomechanical study

Weber,

Lenz,

Egenolf

et al. 2023

J Biomed Mater Res

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Pedicle screw instrumentation has become “state of the art” in surgical treatment of many spinal disorders. Loosening of pedicle screws due to poor bone mineral density is a frequent complication in osteoporotic patients. As prevalence of osteoporosis and spinal disorders are increasing with an aging demographic, optimizing the biomechanical properties of pedicle screw constructions and therefore outcome after spinal surgery in osteoporotic patients is a key factor in future surgical therapy. Therefore, this biomechanical study investigated the stability of polymethylmethacrylate (PMMA)‐augmented pedicle screw‐rod constructions under a deviating distribution of PMMA applied to the instrumentation in osteoporotic human cadaveric vertebrae. We showed that PMMA‐augmented pedicle screw‐rod constructions tend to be more stable than those with non‐augmented pedicle screws. Further, there appears to be a larger risk of screw loosening in unilateral augmented pedicle screws than in non‐augmented, therefore a highly asymmetrically distributed PMMA should be avoided.

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Cyclical Loading to Evaluate the Bone Implant Interface

Swink¹,

Jaffee²,

Diehl³

et al. 2020

Handbook of Spine Technology

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Effect of augmentation techniques on the failure of pedicle screws under cranio-caudal cyclic loading

Cited by 67 publications

References 27 publications

Timing of PMMA cement application for pedicle screw augmentation affects screw anchorage

Timing of PMMA cement application for pedicle screw augmentation affects screw anchorage

Increased stability due to symmetric cement volume in augmented pedicle screws? A biomechanical study

Cyclical Loading to Evaluate the Bone Implant Interface

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