Biomechanical testing of a polycarbonate-urethane-based dynamic instrumentation system under physiological conditions

Beckmann, Agnes; Herren, Christian; Nicolini, Luis Fernando; Grevenstein, David; Oikonomidis, Stavros; Kobbe, Philipp; Hildebrand, Frank; Stoffel, Marcus; Markert, Bernd; Siewe, Jan

doi:10.1016/j.clinbiomech.2018.12.003

Cited by 10 publications

(10 citation statements)

References 34 publications

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“…The ROM of the whole spine (T10-L3) and L1-L2 segment were calculated as described previously by Beckmann et al [18,23]. The Euler angles recorded by the magnetic tracking system were converted to rotation matrices for each sensor.…”

Section: Discussionmentioning

confidence: 99%

“…The ROM was defined as the angular displacement between two vertebrae and was calculated using basis transformations [20]. A sensor was aligned with the universal joint connector at the top of the most cephalic vertebra to detect the main loading direction for the spine in the undeformed state for the cases of flexion-extension and lateral bending [23]. For axial rotation, the main loading direction was set as the plane parallel to the rotatory platform of the machine which has the load cell.…”

Section: Discussionmentioning

confidence: 99%

“…For axial rotation, the main loading direction was set as the plane parallel to the rotatory platform of the machine which has the load cell. The axes of the magnetic tracking receivers' coordinate systems were projected on the primary direction of the load to calculate the 2D ROM [20,23]. The average moment for the same ROM values of the loading and unloading curves of the hysteresis was calculated [25].…”

Section: Discussionmentioning

confidence: 99%

“…Both load cells provide a maximum error of 1% relative to the target or recorder value. An Aurora® electromagnetic tracking system (NDI Europe GmbH, Radolfzell, Germany) was used to track the 6 DoF of microsensors that were inserted in the middle of the vertebral bodies [22,23]. The Euler angles were recorded to detect the orientation of the sensors.…”

Section: Precondition and Flexibility Testingmentioning

confidence: 99%

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Motion preservation surgery for scoliosis with a vertebral body tethering system: a biomechanical study

et al. 2021

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Purpose There is a paucity of studies on new vertebral body tethering (VBT) surgical constructs especially regarding their potentially motion-preserving ability. This study analyses their effects on the ROM of the spine. Methods Human spines (T10-L3) were tested under pure moment in four different conditions: (1) native, (2) instrumented with one tether continuously connected in all vertebrae from T10 to L3, (3) additional instrumented with a second tether continuously connected in all vertebrae from T11 to L3, and (4) instrumented with one tether and one titanium rod (hybrid) attached to T12, L1 and L2. The instrumentation was inserted in the left lateral side. The intersegmental ROM was evaluated using a magnetic tracking system, and the medians were analysed. Please check and confirm the author names and initials are correct. Also, kindly confirm the details in the metadata are correct. The mentioned information is correct Results Compared to the native spine, the instrumented spine presented a reduction of less than 13% in global ROM considering flexion–extension and axial rotation. For left lateral bending, the median global ROM of the native spine (100%) significantly reduced to 74.6%, 66.4%, and 68.1% after testing one tether, two tethers and the hybrid construction, respectively. In these cases, the L1-L2 ROM was reduced to 68.3%, 58.5%, and 38.3%, respectively. In right lateral bending, the normalized global ROM of the spine with one tether, two tethers and the hybrid construction was 58.9%, 54.0%, and 56.6%, respectively. Considering the same order, the normalized L1-L2 ROM was 64.3%, 49.9%, and 35.3%, respectively. Conclusion The investigated VBT techniques preserved global ROM of the spine in flexion–extension and axial rotation while reduced the ROM in lateral bending.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Precondition and Flexibility Testingmentioning

confidence: 99%

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Motion preservation surgery for scoliosis with a vertebral body tethering system: a biomechanical study

et al. 2021

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“…Due to close similarities in anatomy and morphology, porcine bone is a suitable alternative to human bone for investigation of bone implants [31,32]. Specimens were stored at −18 • C and were thawed for over 16 h at 8 • C before testing [33,34]. Each tibia was separated from the knee joint and the fibula, and all soft tissue was removed from the bone.…”

Section: Sample Acquisition and Preparationmentioning

confidence: 99%

Biomechanical Performance of BoneHelix® Compared with Elastic Stable Intramedullary Nailing (ESIN) in a Pediatric Tibia Fracture Model

Brandes

Nicolini

Greven

et al. 2021

Life

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Tibial shaft fractures are common injuries in the pediatric and adolescent populations. Elastic stable intramedullary nailing (ESIN) is the treatment of choice for cases that require surgical stabilization. A new intramedullary device, BoneHelix® (BH), may be an alternative for use with fractures that cannot be satisfactorily stabilized with ESIN. This study aimed to assess the biomechanical performance of BH compared with ESIN in a porcine tibia fracture model, observing cyclic fatigue and load to failure. Computed tomography was used to monitor the implant position and to rule out unintended damage. No implant or bone failure occurred during the fatigue testing. An increase in the cumulative plastic displacement was observed in both test groups over the loading cycles applied. Both implant–bone constructs displayed a trend toward closure of the osteotomy gap. During the load-to-failure test, the average loads at failure in specimens instrumented with ESIN and BH were 5364 N (±723) and 4350 N (±893), respectively, which were not statistically significant (p = 0.11). The values of both groups were two to three times higher than the estimated maximal load (2000 N) during physiological weight bearing. The biomechanical results thus indicate equivalent performance and stability by the implants tested.

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Extension of an In Vitro Spine Test Rig to Track Load‐dependent Biomechanics of the Lumbar Spine under Physiological Conditions

Brenzel,

Blomeyer,

Johnen

et al. 2023

Proc Appl Math and Mech

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Low back pain is a major cause of chronic health problems and is often related to loading history. A test rig was developed at the Institute of General Mechanics, RWTH Aachen University to investigate the influence of duration and intensity of spinal loading using in vitro experiments on spinal cadavers. In this work, several extensions of this spine test rig are presented: (1) a hydraulic cylinder with a force measuring unit was added to apply axial compression; (2) a new follower load principle system was developed to achieve uniform compression of the naturally curved spine; (3) the specimen is immersed in phosphatebuffered saline with protease inhibitors during the testing period to allow osmotic interactions on the one hand and the investigation of the influence of different loading and rest cycles on the other hand; (4) a fiber-optic pressure measurement system was added to successfully measure the intradiscal pressure during the test series. The first results obtained using these test rig extensions and the new pressure measurement system show their functionality. The new test rig enables the investigation of a wide range of load scenarios and further measurement parameters.

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Biomechanical testing of a polycarbonate-urethane-based dynamic instrumentation system under physiological conditions

Cited by 10 publications

References 34 publications

Motion preservation surgery for scoliosis with a vertebral body tethering system: a biomechanical study

Motion preservation surgery for scoliosis with a vertebral body tethering system: a biomechanical study

Biomechanical Performance of BoneHelix® Compared with Elastic Stable Intramedullary Nailing (ESIN) in a Pediatric Tibia Fracture Model

Extension of an In Vitro Spine Test Rig to Track Load‐dependent Biomechanics of the Lumbar Spine under Physiological Conditions

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