Non-fusion instrumentation of the lumbar spine with a hinged pedicle screw rod system: an in vitro experiment

Schmoelz, Werner; Onder, Ursula; Martin, Arno; Strempel, Archibald von

doi:10.1007/s00586-009-1052-3

Cited by 49 publications

(36 citation statements)

References 36 publications

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“…They reported a ROM reduction of 54% in flexion, 39% in extension, 45% in lateral bending, and 7% in axial rotation in comparison to our results of 58.2, 40.4, 46.3, and 52.5%, respectively. The differences in axial rotation could be due to screw loosening, as described by Schmidt et al [24], as the rigid fixation system they tested showed only a decrease of 26%, Abbreviations are explained in Table 1 which is in the lower range compared to other studies [21,[32][33][34][35][36]. FEA studies have shown that rod stiffness plays a major role in stabilizing the segment after treatment with a dynamic rod system.…”

Section: Discussionmentioning

confidence: 88%

The effect of design parameters of dynamic pedicle screw systems on kinematics and load bearing: an in vitro study

Schilling

Krüger²,

Grupp

et al. 2010

Eur Spine J

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As an alternative treatment for chronic back pain due to disc degeneration motion preserving techniques such as posterior dynamic stabilization (PDS) has been clinically introduced, with the intention to alter the load transfer and the kinematics at the affected level to delay degeneration. However, up to the present, it remains unclear when a PDS is clinically indicated and how the ideal PDS mechanism should be designed to achieve this goal. Therefore, the objective of this study was to compare different PDS devices against rigid fixation to investigate the biomechanical impact of PDS design on stabilization and load transfer in the treated and adjacent cranial segment. Six human lumbar spine specimens (L3-L5) were tested in a spine loading apparatus. In vitro flexibility testing was performed by applying pure bending moments of 7.5 Nm without and with additional preload of 400 N in the three principal motion planes. Four PDS devices,

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Section: Discussionmentioning

confidence: 88%

The effect of design parameters of dynamic pedicle screw systems on kinematics and load bearing: an in vitro study

Schilling

Krüger²,

Grupp

et al. 2010

Eur Spine J

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“…The present intact model was validated by comparing our results with those from in vitro and FE studies performed under similar boundary and loading conditions 16,18,19,34,38,48 ( Fig. 2).…”

Section: Range Of Motion and Stress Analysismentioning

confidence: 91%

Instantaneous center of rotation behavior of the lumbar spine with ligament failure

Alapan

Demir

Kaner

et al. 2013

SPI

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Object The goal of this study was to investigate the effect of ligament failure on the instantaneous center of rotation (ICR) in the lower lumbar spine. Methods A 3D finite element model of the L4–5 segment was obtained and validated. Ligament failure was simulated by reducing ligaments in a stepwise manner from posterior to anterior. A pure bending moment of 7.5 Nm was applied to the model in 3 anatomical planes for the purpose of validation, and a 6-Nm moment was applied to analyze the effect of ligament failure. For each loading case, ligament reduction step, and load increment, the range of motion of the segment and the ICR of the mobile (L-4) vertebra were calculated and characterized. Results The present model showed a consistent increase in the range of motion as the ligaments were removed, which was in agreement with the literature reporting the kinematics of the L4–5 segment. The shift in the location of the ICR was below 5 mm in the sagittal plane and 3 mm in both the axial and coronal planes. Conclusions The location of the ICR changed in all planes of motion with the simulation of multiple ligament injury. The removal of the ligaments also changed the load sharing within the motion segment. The change in the center of rotation of the spine together with the change in the range of motion could have a diagnostic value, revealing more detailed information on the type of injury, the state of the ligaments, and load transfer and sharing characteristics of the segment.

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“…Oktenoglu et al reported a unique biomechanical study and found that a dynamic system (dynamic rod and dynamic screws) restores the instable spinal segments to almost normal ROM (15,29). There are recent studies on PTDS with encouraging clinical results showing that PTDS provides stabilization similar to posterior rigid stabilization with fusion surgery (10, 22,23,30,39).…”

Section: Complicationsmentioning

confidence: 99%

A rehabilitation protocol for patients with lumbar degenerative disk disease

Canbulat¹,

Öktenoğlu²,

Ataker³

et al. 2015

Turkish Neurosurgery

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AIm: To evaluate the efficacy of the rehabilitation protocol on patients with lumbar degenerative disc disease after posterior transpedicular dynamic stabilization (PTDS) surgery. mATERIAl and mEThODS: Patients (n=50) with single level lumbar degenerative disc disease were recruited for this study. Patients had PTDS surgery with hinged screws. A rehabilitation program was applied for all patients. Phase 1 was the preoperative evaluation phase. Phase 2 (active rest phase) was the first 6 weeks after surgery. During phase 3 (minimal movement phase, 6-12 weeks) pelvic tilt exercises initiated. In phase 4 (dynamic phase, 3-6 months) dynamic lumbar stabilization exercises were started. Phase 5 (return to sports phase) began after the 6 th month. The primary outcome criteria were the Visual Analogue Pain Score (VAS) and the Oswestry Disability Index (ODI). Patients were evaluated preoperatively, postoperative 3 rd , 12 th and 24 th months. RESUlTS:The mean preoperative VAS and ODI scores were 7.52±0.97 and 60.96±8.74, respectively. During the 3 rd month, VAS and ODI scores decreased to 2.62±1.05 and 26.2±7.93, respectively. VAS and ODI scores continued to decrease during the 12 th month after surgery to 1.4±0.81 and 13.72±6.68, respectively. At the last follow-up (mean 34.1 months) the VAS and ODI scores were found to be 0. 68±0.62 and 7.88±3.32, respectively. (p=0.0001). CONClUSION:The protocol was designed for a postoperative rehabilitation program after PTDS surgery for patients with lumbar degenerative disc disease. The good outcomes are the result of a combination of very careful and restrictive patient selection, surgical technique, and the presented rehabilitation program.

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Non-fusion instrumentation of the lumbar spine with a hinged pedicle screw rod system: an in vitro experiment

Cited by 49 publications

References 36 publications

The effect of design parameters of dynamic pedicle screw systems on kinematics and load bearing: an in vitro study

The effect of design parameters of dynamic pedicle screw systems on kinematics and load bearing: an in vitro study

Instantaneous center of rotation behavior of the lumbar spine with ligament failure

A rehabilitation protocol for patients with lumbar degenerative disk disease

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