Biomechanical Analysis of Transpedicular Screw Fixation in the Subaxial Cervical Spine

Kothe, Ralph; Rüther, W.; Schneider, Erich; Linke, Berend

doi:10.1097/01.brs.0000137287.67388.0b

Cited by 182 publications

(153 citation statements)

References 20 publications

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“…Hence, fatigue analyses are indicated that might show distinct differences among the constructs tested here [19,41]. Kothe [34] performed segmental stabilization of 3-level circumferentially destabilized spines with segmental fixation C3-C6 using all-LMS or all-CPS constructs. Significant differences in primary stability existed only for lateral bending.…”

Section: Discussionmentioning

confidence: 99%

“…We constructed a 2-level corpectomy model with removal of the PLL, others did not [16, 34,49], while the PLL is a known main segmental stabilizer [15]. Ianuzi [23] analyzed the stability afforded by an anterior constrained plate, posterior-constrained LMS, and 360°construct for a 1-level corpectomy model.…”

Section: Discussionmentioning

confidence: 99%

“…We assessed primary stability, and no account was taken for the forces and fatigue noted during repetitive cyclic loading experienced clinically. Repetitive cyclic loading challenges constructs with short screw end-level fixation in merely cancellous bone (anterior plate, all-LMS) far more than those with the transpedicular cortical screw anchorage (CPS-bilat, CPS unilat and ATPS) [33,34]. The mechanical superior characteristics of transpedicular anchorage compared to screws in the lateral mass or vertebral body [26,27] might have significant impact on construct survival.…”

Section: Discussionmentioning

confidence: 99%

“…Yet, a constrained screw-plate system that enables the placement of ATPS besides that of VBS while providing common modern features of rigid screw-plate systems does not exist. Likewise, although transpedicular screw fixation was shown to confer highest fixation characteristics [26,27,29,34], there are no data on the biomechanical characteristic of an ATPS plate to resist the loads that challenge multilevel constructs.…”

Section: Introductionmentioning

confidence: 99%

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The stabilizing potential of anterior, posterior and combined techniques for the reconstruction of a 2-level cervical corpectomy model: biomechanical study and first results of ATPS prototyping

et al. 2010

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Clinical studies reported frequent failure with anterior instrumented multilevel cervical corpectomies. Hence, posterior augmentation was recommended but necessitates a second approach. Thus, an author group evaluated the feasibility, pull-out characteristics, and accuracy of anterior transpedicular screw (ATPS) fixation. Although first success with clinical application of ATPS has already been reported, no data exist on biomechanical characteristics of an ATPS-plate system enabling transpedicular end-level fixation in advanced instabilities. Therefore, we evaluated biomechanical qualities of an ATPS prototype C4-C7 for reduction of range of motion (ROM) and primary stability in a non-destructive setup among five constructs: anterior plate, posterior all-lateral mass screw construct, posterior construct with lateral mass screws C5 ? C6 and end-level fixation using pedicle screws unilaterally or bilaterally, and a 360°construct. 12 human spines C3-T1 were divided into two groups. Four constructs were tested in group 1 and three in group 2; the ATPS prototypes were tested in both groups. Specimens were subjected to flexibility test in a spine motion tester at intact state and after 2-level corpectomy C5-C6 with subsequent reconstruction using a distractable cage and one of the osteosynthesis mentioned above. ROM in flexionextension, axial rotation, and lateral bending was reported as normalized values. All instrumentations but the anterior plate showed significant reduction of ROM for all directions compared to the intact state. The 360°construct outperformed all others in terms of reducing ROM. While there were no significant differences between the 360°a nd posterior constructs in flexion-extension and lateral bending, the 360°constructs were significantly more stable in axial rotation. Concerning primary stability of ATPS prototypes, there were no significant differences compared to posterior-only constructs in flexion-extension and axial rotation. The 360°construct showed significant differences to the ATPS prototypes in flexionextension, while no significant differences existed in axial rotation. But in lateral bending, the ATPS prototype and the anterior plate performed significantly worse than the posterior constructs. ATPS was shown to confer increased primary stability compared to the anterior plate in flexion-extension and axial rotation with the latter yielding significance. We showed that primary stability after 2-level corpectomy reconstruction using ATPS prototypes compared favorably to posterior systems and superior to anterior plates. From the biomechanical point, the 360°i nstrumentation was shown the most efficient for reconstruction of 2-level corpectomies. Further studies will elucidate whether fatigue testing will enhance the benefit of transpedicular anchorage with posterior constructs and ATPS.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The stabilizing potential of anterior, posterior and combined techniques for the reconstruction of a 2-level cervical corpectomy model: biomechanical study and first results of ATPS prototyping

et al. 2010

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“…Biomechanical studies [24,53,54,61,75,86,95,99,100,102,104] and previous clinical studies [11, 22, 48, 55, 61, 62, 66, 73, 75, 90, 95, 100-102, 104, 118] called into question the use of anterior devices in multilevel fusions and corpectomy cases, and support the addition of posterior stabilization, particularly that of pedicle screw fixation [58,59,61,97,100]. However, one has to consider that with the biomechanical advantage of supplemental posterior stabilization is the addition of a second significant surgery and added risks, particularly in elderly and frail patients.…”

Section: Clinical Failures In Multilevel Anterior Cervical Constructsmentioning

confidence: 99%

4- and 5-level anterior fusions of the cervical spine: review of literature and clinical results

et al. 2007

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In the future, there will be an increased number of cervical revision surgeries, including 4-and more-levels. But, there is a paucity of literature concerning the geometrical and clinical outcome in these challenging reconstructions. To contribute to current knowledge, we want to share our experience with 4-and 5-level anterior cervical fusions in 26 cases in sight of a critical review of literature. At index procedure, almost 50% of our patients had previous cervical surgeries performed. Besides failed prior surgeries, indications included degenerative multilevel instability and spondylotic myelopathy with cervical kyphosis. An average of 4.1 levels was instrumented and fused using constrained (26.9%) and non-constrained (73.1%) screw-plate systems. At all, four patients had 3-level corpectomies, and three had additional posterior stabilization and fusion. Mean age of patients at index procedure was 54 years with a mean follow-up intervall of 30.9 months. Preoperative lordosis C2-7 was 6.5°in average, which measured a mean of 15.6°at last follow-up. Postoperative lordosis at fusion block was 14.4°in average, and 13.6°at last follow-up. In 34.6% of patients some kind of postoperative change in construct geometry was observed, but without any catastrophic construct failure. There were two delayed unions, but finally union rate was 100% without any need for the Halo device. Eleven patients (42.3%) showed an excellent outcome, twelve good (46.2%), one fair (3.8%), and two poor (7.7%). The study demonstrated that anterior-only instrumentations following segmental decompressions or use of the hybrid technique with discontinuous corpectomies can avoid the need for posterior supplemental surgery in 4-and 5-level surgeries. However, also the review of literature shows that decreased construct rigidity following more than 2-level corpectomies can demand 360°instrumentation and fusion. Concerning construct rigidity and radiolographic course, constrained plates did better than non-constrained ones. The discussion of our results are accompanied by a detailed review of literature, shedding light on the biomechanical challenges in multilevel cervical procedures and suggests conclusions.

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Characteristics of regional bone quality in cervical vertebrae considering BMD: Determining a safe trajectory for cervical pedicle screw fixation

Kim

Cho

Kwak

et al. 2017

Journal Orthopaedic Research

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This study aimed to report the mechanical strength and characteristics of the lateral mass and pedicle considering BMD for the safe insertion of pedicle screws in the subaxial cervical level. We evaluated BMD and Hounsfield unit (HU) values of cortical bones at the lateral mass and pedicle of C3-7 from CT images in 99 patients. Patients were divided into three groups (Group A, T-score ≥ -1; Group B, -2.5 < T-score < -1.0; Group C, T-score ≤ -2.5). The HU numbers of cortical bone in the vertebral canal (medial wall of the lateral mass; cHU), posterior wall of the transverse foramen (fHU), and medial wall, lateral wall, and trabecular area of the pedicle (mHU, lHU, and pHU, respectively) were measured on the CT images in the middle of the pedicle. A mechanical study was also performed to measure cortical bone strength using 10 fresh cadavers. The cHU and mHU values in Group C were higher than lHU and fHU in Groups A and B, and there was a wide gap between the pHU value and other areas. The penetrating force also had a close correlation with HU number. The mean penetrating force of the medial wall of the lateral mass and the posterior wall of the transverse foramen were 210.08 ± 110.46 and 50.51 ± 46.09 N, respectively. The cortical bones in the vertebral canal and medial wall of the pedicle were stronger than the lateral wall and the trabecular area. The cHU and mHU in the osteoporotic group were higher than fHU and pHU in the normal group. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:217-223, 2018.

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Biomechanical Analysis of Transpedicular Screw Fixation in the Subaxial Cervical Spine

Cited by 182 publications

References 20 publications

The stabilizing potential of anterior, posterior and combined techniques for the reconstruction of a 2-level cervical corpectomy model: biomechanical study and first results of ATPS prototyping

The stabilizing potential of anterior, posterior and combined techniques for the reconstruction of a 2-level cervical corpectomy model: biomechanical study and first results of ATPS prototyping

4- and 5-level anterior fusions of the cervical spine: review of literature and clinical results

Characteristics of regional bone quality in cervical vertebrae considering BMD: Determining a safe trajectory for cervical pedicle screw fixation

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