Design and Research of Interspinous Lumbar Non-Fusion Device

2010 ◽  
Author(s):  
Lei Li ◽  
Zhaohua Chang ◽  
Xuelian Gu ◽  
Chengli Song
Keyword(s):  
Stress Concentration ◽  
Vertebral Body ◽  
Interbody Fusion ◽  
Lumbar Fusion ◽  
Pedicle Screws ◽  
Adjacent Level ◽  
Flexion Extension ◽  
Fusion Cage ◽  
Adjacent Level Degeneration ◽  
Interbody Fusion Cage

Objective: Long term clinical data showed that lumbar fusion for Lumbar spinal stenosis (LSS) and lumbar disc degeneration (LDD) therapy could change the loads of disc and articular facet and increase the motion of adjacent segments which lead to facet arthropathy and adjacent level degeneration. This study is to design and analyze an interspinous process device (IPD) that could prevent adjacent level degeneration in the LSS and LDD therapy. Method: The IPD was designed based on anatomical parameters measured from 3D CT images directly. The IPD was inserted at the validated finite element model of the mono-segmental L3/L4. The biomechanical performance of a pair of interbody fusion cages and a paired pedicel screws were studied to compare with the IPD. The model was loaded with the upper body weight and muscle forces to simulate five loading cases including standing, compression, flexion, extension, lateral bending and axial rotation. Results: The interbody fusion cage induced serious stress concentration on the surface of vertebral body, has the worst biomechanical performance among the three systems. Pedicle screws and interbody fusion cage could induce stress concentration within vertebral body which leads to vertebral compression fracture or screw loosening. Regarding to disc protection, the IPD had higher percentage to share the load of posterior lumbar structure than the pedicel screws and interbody fusion cage. Conclusion: IPD has the same loads as pedicle screw-rod which suggests it has a good function in the posterior stability. While the IPD had much less influence on vertebral body. Furthermore, IPD could share the load of intervertebral discs and facet joints to maintain the stability of lumbar spine.

Evaluation of Lumbar Spine Stabilization Using Anterior Interbody Fusion Cage

2002 ◽  
Author(s):  
Robert X. Gao ◽  
Mathew E. Mitchell ◽  
R. Scott Cowan
Keyword(s):  
Lumbar Spine ◽  
Interbody Fusion ◽  
Lumbar Fusion ◽  
Healing Process ◽  
Spine Stabilization ◽  
Anterior Interbody Fusion ◽  
Wide Range ◽  
Flexion Extension ◽  
Fusion Cage ◽  
Interbody Fusion Cage

Spinal surgery uses a wide range of instrumentation devices to provide comfort to the patient, stabilize the spine, and enhance the bony healing process after surgery. In order to improve upon the effectiveness of these devices, the interaction between the spine and the implant devices needs to be studied from both medical and engineering perspectives. This paper investigates the effect of an anterior interbody fusion cage on lumbar spine stabilization, by means of numerical analysis using the finite element technique and experimental testing. Specifically, the relative displacement within an intact L4-L5 motion segment has been simulated and measured, under a range of compression, flexion, extension, torsion, and lateral bending loads. Subsequently, the effect of a single anterior lumbar fusion cage implanted into the segment was simulated and experimentally validated, under similar loading conditions. Comparison between the intact and cage-implanted segments indicated varying stabilizing ability of the fusion cage, which is highly dependent upon the cage position and the type of loading.

Adjacent-segment effects of lumbar cortical screw–rod fixation versus pedicle screw–rod fixation with and without interbody support

2021 ◽  
pp. 1-7
Author(s):  
Piyanat Wangsawatwong ◽  
Anna G. U. Sawa ◽  
Bernardo de Andrada Pereira ◽  
Jennifer N. Lehrman ◽  
Luke K. O’Neill ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Interbody Fusion ◽  
Lumbar Fusion ◽  
Statistical Significance ◽  
Adjacent Segment ◽  
Lumbar Interbody Fusion ◽  
Lateral Bending ◽  
Single Level ◽  
Cortical Screw ◽  
Flexion Extension

OBJECTIVE Cortical screw–rod (CSR) fixation has emerged as an alternative to the traditional pedicle screw–rod (PSR) fixation for posterior lumbar fixation. Previous studies have concluded that CSR provides the same stability in cadaveric specimens as PSR and is comparable in clinical outcomes. However, recent clinical studies reported a lower incidence of radiographic and symptomatic adjacent-segment degeneration with CSR. No biomechanical study to date has focused on how the adjacent-segment mobility of these two constructs compares. This study aimed to investigate adjacent-segment mobility of CSR and PSR fixation, with and without interbody support (lateral lumbar interbody fusion [LLIF] or transforaminal lumbar interbody fusion [TLIF]). METHODS A retroactive analysis was done using normalized range of motion (ROM) data at levels adjacent to single-level (L3–4) bilateral screw–rod fixation using pedicle or cortical screws, with and without LLIF or TLIF. Intact and instrumented specimens (n = 28, all L2–5) were tested using pure moment loads (7.5 Nm) in flexion, extension, lateral bending, and axial rotation. Adjacent-segment ROM data were normalized to intact ROM data. Statistical comparisons of adjacent-segment normalized ROM between two of the groups (PSR followed by PSR+TLIF [n = 7] and CSR followed by CSR+TLIF [n = 7]) were performed using 2-way ANOVA with replication. Statistical comparisons among four of the groups (PSR+TLIF [n = 7], PSR+LLIF [n = 7], CSR+TLIF [n = 7], and CSR+LLIF [n = 7]) were made using 2-way ANOVA without replication. Statistical significance was set at p < 0.05. RESULTS Proximal adjacent-segment normalized ROM was significantly larger with PSR than CSR during flexion-extension regardless of TLIF (p = 0.02), or with either TLIF or LLIF (p = 0.04). During lateral bending with TLIF, the distal adjacent-segment normalized ROM was significantly larger with PSR than CSR (p < 0.001). Moreover, regardless of the types of screw-rod fixations (CSR or PSR), TLIF had a significantly larger normalized ROM than LLIF in all directions at both proximal and distal adjacent segments (p ≤ 0.04). CONCLUSIONS The use of PSR versus CSR during single-level lumbar fusion can significantly affect mobility at the adjacent segment, regardless of the presence of TLIF or with either TLIF or LLIF. Moreover, the type of interbody support also had a significant effect on adjacent-segment mobility.

Hybrid dynamic stabilization: a biomechanical assessment of adjacent and supraadjacent levels of the lumbar spine

2012 ◽  
Vol 17 (3) ◽  
pp. 232-242 ◽  
Author(s):  
Prasath Mageswaran ◽  
Fernando Techy ◽  
Robb W. Colbrunn ◽  
Tara F. Bonner ◽  
Robert F. McLain
Keyword(s):  
Lumbar Spine ◽  
Lumbar Fusion ◽  
Industrial Robot ◽  
Pedicle Screws ◽  
Axial Rotation ◽  
Dynamic Stabilization ◽  
Follower Load ◽  
Lateral Bending ◽  
Intact Specimen ◽  
Flexion Extension

Object The object of this study was to evaluate the effect of hybrid dynamic stabilization on adjacent levels of the lumbar spine. Methods Seven human spine specimens from T-12 to the sacrum were used. The following conditions were implemented: 1) intact spine; 2) fusion of L4–5 with bilateral pedicle screws and titanium rods; and 3) supplementation of the L4–5 fusion with pedicle screw dynamic stabilization constructs at L3–4, with the purpose of protecting the L3–4 level from excessive range of motion (ROM) and to create a smoother motion transition to the rest of the lumbar spine. An industrial robot was used to apply continuous pure moment (± 2 Nm) in flexion-extension with and without a follower load, lateral bending, and axial rotation. Intersegmental rotations of the fused, dynamically stabilized, and adjacent levels were measured and compared. Results In flexion-extension only, the rigid instrumentation at L4–5 caused a 78% decrease in the segment's ROM when compared with the intact specimen. To compensate, it caused an increase in motion at adjacent levels L1–2 (45.6%) and L2–3 (23.2%) only. The placement of the dynamic construct at L3–4 decreased the operated level's ROM by 80.4% (similar stability as the fusion at L4–5), when compared with the intact specimen, and caused a significant increase in motion at all tested adjacent levels. In flexion-extension with a follower load, instrumentation at L4–5 affected only a subadjacent level, L5–sacrum (52.0%), while causing a reduction in motion at the operated level (L4–5, −76.4%). The dynamic construct caused a significant increase in motion at the adjacent levels T12–L1 (44.9%), L1–2 (57.3%), and L5–sacrum (83.9%), while motion at the operated level (L3–4) was reduced by 76.7%. In lateral bending, instrumentation at L4–5 increased motion at only T12–L1 (22.8%). The dynamic construct at L3–4 caused an increase in motion at T12–L1 (69.9%), L1–2 (59.4%), L2–3 (44.7%), and L5–sacrum (43.7%). In axial rotation, only the placement of the dynamic construct at L3–4 caused a significant increase in motion of the adjacent levels L2–3 (25.1%) and L5–sacrum (31.4%). Conclusions The dynamic stabilization system displayed stability characteristics similar to a solid, all-metal construct. Its addition of the supraadjacent level (L3–4) to the fusion (L4–5) did protect the adjacent level from excessive motion. However, it essentially transformed a 1-level lumbar fusion into a 2-level lumbar fusion, with exponential transfer of motion to the fewer remaining discs.

scholarly journals Learning curve and complications of minimally invasive transforaminal lumbar interbody fusion

2013 ◽  
Vol 35 (2) ◽  
pp. E7 ◽  
Author(s):  
Pedro S. Silva ◽  
Paulo Pereira ◽  
Pedro Monteiro ◽  
Pedro A. Silva ◽  
Rui Vaz
Keyword(s):  
Minimally Invasive ◽  
Learning Curve ◽  
Interbody Fusion ◽  
Operative Time ◽  
Pedicle Screws ◽  
Transforaminal Lumbar Interbody Fusion ◽  
Complication Rates ◽  
Lumbar Interbody Fusion ◽  
Adjacent Level ◽  
Negative Exponential

Object Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) has the potential advantage of minimizing soft-tissue damage and reducing recovery time compared to open procedures. A steep learning curve has been described for the technique. The aim of the present study was to define the learning curve that describes the progress of a single surgeon performing the MI-TLIF. Methods One hundred fifty consecutive patients with degenerative lumbar disease who underwent 1- or 2-level MI-TLIF were included in the study. Operative time, corrected operative time per level, and complications were analyzed. The learning curve was assessed using a negative exponential curve-fit regression analysis. Results One hundred ten patients underwent 1-level and 18 patients underwent 2-level MI-TLIF; the remaining 22 underwent a single-level procedure plus an ancillary procedure (decompression at adjacent level, vertebral augmentation through fenestrated pedicle screws, interspinous device at adjacent level). Negative exponential curves appropriately described the relationship between operative time and experience for 1-level surgery and after correction of operative time per level (R2 = 0.65 and 0.57). The median operative time was 140 minutes (interquartile range 120–173 minutes), and a 50% learning milestone was achieved at Case 12; a 90% learning milestone was achieved at Case 39. No patient required transfusion in the perioperative period. The overall complication rate was 12.67% and the most frequent complication was a dural tear (5.32%). Before the 50% and 90% learning milestones, the complication rates were 33% and 20.51%, respectively. Conclusions The MI-TLIF is a reliable and effective option for lumbar arthrodesis. According to the present study, 90% of the learning curve can be achieved at around the 40th case.

Biomechanical comparison of transdiscal fixation and posterior fixation with and without transforaminal lumbar interbody fusion in the treatment of L5–S1 lumbosacral joint

2018 ◽  
Vol 232 (4) ◽  
pp. 371-377 ◽  
Author(s):  
Hakan Özalp ◽  
Mustafa Özkaya ◽  
Onur Yaman ◽  
Teyfik Demir
Keyword(s):  
Pedicle Screw ◽  
Axial Compression ◽  
Interbody Fusion ◽  
Screw Fixation ◽  
Transforaminal Lumbar Interbody Fusion ◽  
Pedicle Screw Fixation ◽  
Posterior Fixation ◽  
Lumbar Interbody Fusion ◽  
Fusion Cage ◽  
Interbody Fusion Cage

Transdiscal screw fixation is generally performed in the treatment of high-grade L5–S1 spondylolisthesis. The main thought of the study is that the biomechanical performances of the transdiscal pedicle screw fixation can be identical to standard posterior pedicle screw fixations with or without transforaminal lumbar interbody fusion cage insertion. Lumbosacral portions and pelvises of 45 healthy lambs’ vertebrae were dissected. Animal cadavers were randomly and equally divided into three groups for instrumentation. Three fixation systems, L5–S1 posterior pedicle screw fixation, L5–S1 posterior pedicle screw fixation with transforaminal lumbar interbody fusion cage insertion, and L5–S1 transdiscal pedicle screw fixation, were generated. Axial compression, flexion, and torsion tests were conducted on test samples of each system. In axial compression, L5–S1 transdiscal fixation was less stiff than L5–S1 posterior pedicle screw fixation with transforaminal lumbar interbody fusion cage insertion. There were no significant differences between groups in flexion. Furthermore, L5–S1 posterior fixation was stiffest under torsional loads. When axial compression and flexion loads are taken into consideration, transdiscal fixation can be alternatively used instead of posterior pedicle screw fixation in the treatment of L5–S1 spondylolisthesis because it satisfies enough stability. However, in torsion, posterior fixation is shown as a better option due to its higher stiffness.

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