Biomechanical analysis of an expandable lateral cage and a static transforaminal lumbar interbody fusion cage with posterior instrumentation in an in vitro spondylolisthesis model

OBJECT Insufficient biomechanical data exist from comparisons of the stability of expandable lateral cages with that of static transforaminal lumbar interbody fusion (TLIF) cages. The purpose of this biomechanical study was to compare the relative rigidity of L4–5 expandable lateral interbody constructs with or without additive pedicle screw fixation with that of L4–5 static TLIF cages in a novel cadaveric spondylolisthesis model. METHODS Eight human cadaver spines were used in this study. A spondylolisthesis model was created at the L4–5 level by creating 2 injuries. First, in each cadaver, a nucleotomy from 2 channels through the anterior side was created. Second, the cartilage of the facet joint was burred down to create a gap of 4 mm. Light-emitting-diode tracking markers were placed at L-3, L-4, L-5, and S-1. Specimens were tested in the following scenarios: intact model, bilateral pedicle screws, expandable lateral 18-mm-wide cage (alone, with unilateral pedicle screws [UPSs], and with bilateral pedicle screws [BPSs]), expandable lateral 22-mm-wide cage (alone, with UPSs, and with BPSs), and TLIF (alone, with UPSs, and with BPSs). Four of the spines were tested with the expandable lateral cages (18-mm cage followed by the 22-mm cage), and 4 of the spines were tested with the TLIF construct. All these constructs were tested in flexion-extension, axial rotation, and lateral bending. RESULTS The TLIF-alone construct was significantly less stable than the 18- and 22-mm-wide lateral lumbar interbody fusion (LLIF) constructs and the TLIF constructs with either UPSs or BPSs. The LLIF constructs alone were significantly less stable than the TLIF construct with BPSs. However, there was no significant difference between the 18-mm LLIF construct with UPSs and the TLIF construct with BPSs in any of the loading modes. CONCLUSIONS Expandable lateral cages with UPSs provide stability equivalent to that of a TLIF construct with BPSs in a degenerative spondylolisthesis model.

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Revision of transforaminal lumbar interbody fusion using anterior lumbar interbody fusion: a biomechanical study in nonosteoporotic bone

Journal of Neurosurgery Spine ◽

10.3171/2009.7.spine0921 ◽

2010 ◽

Vol 12 (1) ◽

pp. 82-87 ◽

Cited By ~ 5

Author(s):

Avraam Ploumis ◽

Chunhui Wu ◽

Amir Mehbod ◽

Gustav Fischer ◽

Antonio Faundez ◽

...

Keyword(s):

Interbody Fusion ◽

Posterior Instrumentation ◽

Transforaminal Lumbar Interbody Fusion ◽

Anterior Lumbar Interbody Fusion ◽

Posterior Fixation ◽

Lumbar Interbody Fusion ◽

Mineral Density ◽

Normal Bone Mineral Density ◽

Flexion Extension

Object Transforaminal lumbar interbody fusion (TLIF) is a popular fusion technique for treating chronic low-back pain. In cases of interbody nonfusion, revision techniques for TLIF include anterior lumbar interbody fusion (ALIF) approaches. Biomechanical data of the revision techniques are not available. The purpose of this study was to compare the immediate construct stability, in terms of range of motion (ROM) and neutral zone (NZ), of a revision ALIF procedure for an unsuccessful TLIF. An in vitro biomechanical comparison of TLIF and its ALIF revision procedure was conducted on cadaveric nonosteoporotic human spine segments. Methods Twelve cadaveric lumbar motion segments with normal bone mineral density were loaded in unconstrained axial torsion, lateral bending, and flexion-extension under 0.05 Hz and ± 6-nm sinusoidal waveform. The specimens underwent TLIF (with posterior pedicle fixation) and anterior ALIF (with intact posterior fixation). Multidirectional flexibility testing was conducted following each step. The ROM and NZ data were measured and calculated for each test. Results Globally, the TLIF and revision ALIF procedures significantly reduced ROM and NZ compared with that of the intact condition. The revision ALIF procedures achieved similar ROM as the TLIF procedure. Conclusions Revision ALIF maintained biomechanical stability of TLIF in nonosteoporotic spines. Revision ALIF can be performed without sacrificing spinal stability in cases of intact posterior instrumentation.

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Assessment of L5–S1 anterior lumbar interbody fusion stability in the setting of lengthening posterior instrumentation constructs: a cadaveric biomechanical study

Journal of Neurosurgery Spine ◽

10.3171/2021.9.spine21821 ◽

2021 ◽

pp. 1-9

Keyword(s):

Interbody Fusion ◽

Posterior Instrumentation ◽

Pedicle Screws ◽

Axial Rotation ◽

Anterior Lumbar Interbody Fusion ◽

Posterior Fusion ◽

Lumbar Interbody Fusion ◽

Lateral Bending ◽

Fusion Construct ◽

Flexion Extension

OBJECTIVE Excessive stress and motion at the L5–S1 level can lead to degenerative changes, especially in patients with posterior instrumentation suprajacent to L5. Attention has turned to utilization of L5–S1 anterior lumbar interbody fusion (ALIF) to stabilize the lumbosacral junction. However, questions remain regarding the effectiveness of stand-alone ALIF in the setting of prior posterior instrumented fusions terminating at L5. The purpose of this study was to assess the biomechanical stability of an L5–S1 ALIF with increasing lengths of posterior thoracolumbar constructs. METHODS Seven human cadaveric spines (T9–sacrum) were instrumented with pedicle screws from T10 to L5 and mounted to a 6 degrees-of-freedom robot. Posterior fusion construct lengths (T10–L5, T12–L5, L2–5, and L4–5) were instrumented to each specimen, and torque-fusion level relationships were determined for each construct in flexion-extension, axial rotation, and lateral bending. A stand-alone L5–S1 ALIF was then instrumented, and L5–S1 motion was measured as increasing pure moments (2 to 12 Nm) were applied. Motion reduction was calculated by comparing L5–S1 motion across the ALIF and non-ALIF states. RESULTS The average motion at L5–S1 in axial rotation, flexion-extension, and lateral bending was assessed for each fusion construct with and without ALIF. After adding ALIF to a posterior fusion, L5–S1 motion was significantly reduced relative to the non-ALIF state in all but one fused surgical condition (p < 0.05). Longer fusions with ALIF produced larger L5–S1 motions, and in some cases resulted in motions higher than native state motion. CONCLUSIONS Posterior fusion constructs up to L4–5 could be appropriately stabilized by a stand-alone L5–S1 ALIF when using a nominal threshold of 80% reduction in native motion as a potential positive indicator of fusion. The results of this study allow conclusions to be drawn from a biomechanical standpoint; however, the clinical implications of these data are not well defined. These findings, when taken in appropriate clinical context, can be used to better guide clinicians seeking to treat L5–S1 pathology in patients with prior posterior thoracolumbar constructs.

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Biomechanical Comparison of Transforaminal Lumbar Interbody Fusion With 1 or 2 Cages by Finite-Element Analysis

Operative Neurosurgery ◽

10.1227/01.neu.0000430320.39870.f7 ◽

2013 ◽

Vol 73 (2) ◽

pp. ons198-ons205 ◽

Cited By ~ 3

Author(s):

Hao Xu ◽

Wen Ju ◽

Neng Xu ◽

Xiaojian Zhang ◽

Xiaodong Zhu ◽

...

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Bone Graft ◽

Interbody Fusion ◽

Transforaminal Lumbar Interbody Fusion ◽

Lumbar Interbody Fusion ◽

Element Analysis ◽

Single Cage ◽

Significant Difference ◽

Flexion Extension

Abstract BACKGROUND: Anterior lumbar interbody fusion and posterior lumbar interbody fusion with 1 cage have been shown to have similar biomechanics compared with the use of 2 cages. However, there have been no reports on the biomechanical differences between using 1 or 2 cages in transforaminal lumbar interbody fusion (TLIF) surgery. OBJECTIVE: To determine the biomechanical differences between the use of 1 or 2 cages in TLIF by finite-element analysis. METHODS: Three validated finite-element models of the L3-L5 lumbar segment were created (intact model and single- and paired-cage TLIF models). To study the biomechanics, a compressive preload of 400 N over 7.5 N-m was applied to the superior surfaces of the L3 vertebral body to simulate flexion, extension, rotation, and lateral bending. RESULTS: There was no significant difference in the range of motion between single-cage and paired-cage TLIF models, < 1° for all loading cases. Cage stress was high in the single-cage TLIF model under all loading conditions. Bone graft stress was high in the single-cage TLIF model. Pedicle screw stress was higher in the single-cage compared with the paired-cage TLIF. CONCLUSION: Single-cage TLIF approximates biomechanical stability and increases the stress of the bone graft. The use of a single cage may simplify the standard TLIF procedure, shorten operative times, decrease cost, and provide satisfactory clinical outcomes. Thus, single-cage TLIF is a useful alternative to traditional 2-cage TLIF.

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Minimally invasive versus traditional open transforaminal lumbar interbody fusion for the treatment of low-grade degenerative spondylolisthesis: a retrospective study

Scientific Reports ◽

10.1038/s41598-020-78984-x ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Rongqing Qin ◽

Tong Wu ◽

Hongpeng Liu ◽

Bing Zhou ◽

Pin Zhou ◽

...

Keyword(s):

Interbody Fusion ◽

Degenerative Spondylolisthesis ◽

Transforaminal Lumbar Interbody Fusion ◽

Low Grade ◽

Lumbar Interbody Fusion ◽

Efficacy And Safety ◽

Slip Ratio ◽

Significant Difference ◽

Time Point

AbstractThis was a retrospective study. We aimed to compare the clinical efficacy and safety between minimally invasive and traditional open transforaminal lumbar interbody fusion in the treatment of low-grade lumbar degenerative spondylolisthesis (LDS). 81 patients with LDS grades 1 and 2 treated in our spinal department from January 2014 to July 2016 were retrospectively analyzed. The MIS-TLIF group included 23 males and 11 females, while the TO-TLIF group included 29 males and 18 females. Follow-up points were set at 7 days, 3 months, 6 months, 12 months postoperatively and the last follow-up. Various clinical and radiological indicators were used to evaluate and compare the efficacy and safety between the two procedures. 8 cases (3 in the MIS-TLIF group and 5 in the TO-TLIF group) were loss of follow-up after discharge. And the remaining 73 patients were followed up for at least 2 years. No statistically significant difference was observed in the terms of age, sex, BMI, slippage grade, and surgical segments. The MIS-TLIF group had a longer operation and fluoroscopy time compared with the TO-TLIF group. But the MIS-TLIF group was associated with less blood loss, ambulation time, hospital stay, and time of return to work. In each group, significant improvement were observed in BP-VAS, ODI and vertebral slip ratio at any time-point of follow-up when compared with the preoperative condition. When the time-point of follow-up was less than 1 year, the MIS-TLIF group had significant advantages in the BP-VAS and ODI compared with TO-TLIF group. But no significant difference was observed in the BP-VAS and ODI at either 12 month follow-up or the last follow-up. Besides, no statistical difference was detected in vertebral slip ratio at any time-point of follow-up between the two groups. Successful intervertebral bone fusion was found in all patients and no significant difference was found in the incidence of total complications. Thus, we considered that MIS-TLIF and TO-TLIF both achieve satisfactory clinical efficacy in the treatment of low-grade single-segment LDS. But MIS-TLIF appears to be a more efficacious and safe technique with reduced tissue damage, less blood loss and quicker recovery.

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Biomechanical evaluation of lateral lumbar interbody fusion with secondary augmentation

Journal of Neurosurgery Spine ◽

10.3171/2016.4.spine151386 ◽

2016 ◽

Vol 25 (6) ◽

pp. 720-726 ◽

Cited By ~ 14

Author(s):

Marco T. Reis ◽

Phillip M. Reyes ◽

Idris Altun ◽

Anna G. U. S. Newcomb ◽

Vaneet Singh ◽

...

Keyword(s):

Interbody Fusion ◽

Pedicle Screws ◽

Axial Rotation ◽

Lumbar Interbody Fusion ◽

Lateral Bending ◽

Lateral Lumbar Interbody Fusion ◽

Significant Difference ◽

Flexion Extension ◽

Supplemental Fixation ◽

The Stability

OBJECTIVE Lateral lumbar interbody fusion (LLIF) has emerged as a popular method for lumbar fusion. In this study the authors aimed to quantify the biomechanical stability of an interbody implant inserted using the LLIF approach with and without various supplemental fixation methods, including an interspinous plate (IP). METHODS Seven human cadaveric L2–5 specimens were tested intact and in 6 instrumented conditions. The interbody implant was intended to be used with supplemental fixation. In this study, however, the interbody was also tested without supplemental fixation for a relative comparison of these conditions. The instrumented conditions were as follows: 1) interbody implant without supplemental fixation (LLIF construct); and interbody implant with supplemental fixation performed using 2) unilateral pedicle screws (UPS) and rod (LLIF + UPS construct); 3) bilateral pedicle screws (BPS) and rods (LLIF + BPS construct); 4) lateral screws and lateral plate (LP) (LLIF + LP construct); 5) interbody LP and IP (LLIF + LP + IP construct); and 6) IP (LLIF + IP construct). Nondestructive, nonconstraining torque (7.5 Nm maximum) induced flexion, extension, lateral bending, and axial rotation, whereas 3D specimen range of motion (ROM) was determined optoelectronically. RESULTS The LLIF construct reduced ROM by 67% in flexion, 52% in extension, 51% in lateral bending, and 44% in axial rotation relative to intact specimens (p < 0.001). Adding BPS to the LLIF construct caused ROM to decrease by 91% in flexion, 82% in extension and lateral bending, and 74% in axial rotation compared with intact specimens (p < 0.001), providing the greatest stability among the constructs. Adding UPS to the LLIF construct imparted approximately one-half the stability provided by LLIF + BPS constructs, demonstrating significantly smaller ROM than the LLIF construct in all directions (flexion, p = 0.037; extension, p < 0.001; lateral bending, p = 0.012) except axial rotation (p = 0.07). Compared with the LLIF construct, the LLIF + LP had a significant reduction in lateral bending (p = 0.012), a moderate reduction in axial rotation (p = 0.18), and almost no benefit to stability in flexion-extension (p = 0.86). The LLIF + LP + IP construct provided stability comparable to that of the LLIF + BPS. The LLIF + IP construct provided a significant decrease in ROM compared with that of the LLIF construct alone in flexion and extension (p = 0.002), but not in lateral bending (p = 0.80) and axial rotation (p = 0.24). No significant difference was seen in flexion, extension, or axial rotation between LLIF + BPS and LLIF + IP constructs. CONCLUSIONS The LLIF construct that was tested significantly decreased ROM in all directions of loading, which indicated a measure of inherent stability. The LP significantly improved the stability of the LLIF construct in lateral bending only. Adding an IP device to the LLIF construct significantly improves stability in sagittal plane rotation. The LLIF + LP + IP construct demonstrated stability comparable to that of the gold standard 360° fixation (LLIF + BPS).

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Biomechanical Analysis of Cortical Versus Pedicle Screw Fixation Stability in TLIF, PLIF, and XLIF Applications

Global Spine Journal ◽

10.1177/2192568218779991 ◽

2018 ◽

Vol 9 (2) ◽

pp. 162-168 ◽

Cited By ~ 4

Author(s):

Edward K. Nomoto ◽

Guy R. Fogel ◽

Alexandre Rasouli ◽

Justin V. Bundy ◽

Alexander W. Turner

Keyword(s):

Pedicle Screw ◽

Interbody Fusion ◽

Screw Fixation ◽

Pedicle Screws ◽

Axial Rotation ◽

Biomechanical Analysis ◽

Lumbar Interbody Fusion ◽

Lateral Bending ◽

Cortical Screw ◽

Flexion Extension

Study Design: Cadaveric biomechanical study. Objectives: Medial-to-lateral trajectory cortical screws are of clinical interest due to the ability to place them through a less disruptive, medialized exposure compared with conventional pedicle screws. In this study, cortical and pedicle screw trajectory stability was investigated in single-level transforaminal lumbar interbody fusion (TLIF), posterior lumbar interbody fusion (PLIF), and extreme lateral interbody fusion (XLIF) constructs. Methods: Eight lumbar spinal units were used for each interbody/screw trajectory combination. The following constructs were tested: TLIF + unilateral facetectomy (UF) + bilateral pedicle screws (BPS), TLIF + UF + bilateral cortical screws (BCS), PLIF + medial facetectomy (MF) + BPS, PLIF + bilateral facetectomy (BF) + BPS, PLIF + MF + BCS, PLIF + BF + BCS, XLIF + BPS, XLIF + BCS, and XLIF + bilateral laminotomy + BCS. Range of motion (ROM) in flexion-extension, lateral bending, and axial rotation was assessed using pure moments. Results: All instrumented constructs were significantly more rigid than intact ( P < .05) in all test directions except TLIF + UF + BCS, PLIF + MF + BCS, and PLIF + BF + BCS in axial rotation. In general, XLIF and PLIF + MF constructs were more rigid (lowest ROM) than TLIF + UF and PLIF + BF constructs. In the presence of substantial iatrogenic destabilization (TLIF + UF and PLIF + BF), cortical screw constructs tended to be less rigid (higher ROM) than the same pedicle screw constructs in lateral bending and axial rotation; however, no statistically significant differences were found when comparing pedicle and cortical fixation for the same interbody procedures. Conclusions: Both cortical and pedicle trajectory screw fixation provided stability to the 1-level interbody constructs. Constructs with the least iatrogenic destabilization were most rigid. The more destabilized constructs showed less lateral bending and axial rotation rigidity with cortical screws compared with pedicle screws. Further investigation is warranted to understand the clinical implications of differences between constructs.

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Cortical Bone Trajectory Screws in Posterior Lumbar Interbody Fusion: Minimally Invasive Surgery for Maximal Muscle Sparing—A Prospective Comparative Study with the Traditional Open Technique

BioMed Research International ◽

10.1155/2018/7424568 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7 ◽

Cited By ~ 14

Author(s):

Nicola Marengo ◽

Marco Ajello ◽

Michele Federico Pecoraro ◽

Giulia Pilloni ◽

Giovanni Vercelli ◽

...

Keyword(s):

Comparative Study ◽

Interbody Fusion ◽

Pedicle Screws ◽

Posterior Lumbar Interbody Fusion ◽

Fusion Rate ◽

Lumbar Interbody Fusion ◽

Significant Difference ◽

Prospective Comparative Study ◽

One Year ◽

Muscular Damage

Introduction. A prospective comparative study between classical posterior interbody fusion with peduncular screws and the new technique with divergent cortical screws was conducted. Material and Methods. Only patients with monosegmental degenerative disease were recruited into this study. We analyzed a cohort of 40 patients treated from January 2015 to March 2016 divided into 2 groups (20 patients went to traditional open surgery and 20 patients under mini-invasive strategy). Primary endpoints of this study are fusion rate and muscular damage; secondary endpoints analyzed were three different clinical scores (ODI, VAS, and EQ) and the morbidity rate of both techniques. Results. There was no significant difference in fusion rate between the two techniques. In addition, a significant difference in muscular damage was found according to the MRI evaluation. Clinical outcomes, based on pain intensity, Oswestry Disability Index status, and Euroquality-5D score, were found to be also statistically different, even one year after surgery. This study also demonstrated a correlation between patients’ muscular damage and their clinical outcome. Conclusions. Cortical bone trajectory screws would provide similar outcomes compared to pedicle screws in posterior lumbar interbody fusion at one year after surgery, and this technique represents a reasonable alternative to pedicle screws.

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Alloplastic or Autologous? Bone Chips versus PEEK Cage for Lumbar Interbody Fusion in Degenerative Spondylolisthesis

Journal of Neurological Surgery Part A Central European Neurosurgery ◽

10.1055/s-0040-1718770 ◽

2021 ◽

Author(s):

Stefan Koehler ◽

Christopher Held ◽

Christian Stetter ◽

Thomas Westermaier

Keyword(s):

Interbody Fusion ◽

Posterior Instrumentation ◽

Degenerative Spondylolisthesis ◽

Leg Pain ◽

Lumbar Interbody Fusion ◽

Peek Cage ◽

Cheap Alternative ◽

Autologous Bone ◽

Group 2 ◽

Group 1

Abstract Introduction This study was conducted to compare bone-filled intervertebral cages with autologous bone chips for instrumented lumbar interbody fusion in patients with spinal stenosis and degenerative spondylolisthesis. Methods Surgery consisted of posterior instrumentation and decompression, diskectomy, and intervertebral fusion using a polyetheretherketone (PEEK) cage surrounded and filled with spongious bone chips (group 1, n = 57) or spongious bone chips alone (group 2, n = 37). The choice of method was left to the discretion of the surgeon. Postoperative results were prospectively evaluated using a standardized protocol. Radiological assessment included fusion rates and vertebral height, while clinical assessment included the visual analog scale (VAS) and Oswestry Disability Index (ODI). Results In group 1, a mean of 1.38 ± 0.64 segments were fused. In group 2, a mean of 1.58 ± 0.65 segments were fused. In both groups, the VAS for back pain and leg pain and the ODI improved without significant differences between the two groups. Osseous fusion was documented by computerized tomography in 73% in group 1 and 89% in group 2 after a mean of 18 months. The loss of height was 2.8 ± 4.0% in group 1 and 2.4 ± 5.2% in group 2. Conclusion Regardless of whether a PEEK cage filled with spongious bone chips or spongious bone chips alone were used for lumbar interbody fusion, clinical parameters improved significantly after surgery. There were no significant differences in the rate of bony fusion and loss of height between the two groups. The results of this nonrandomized cohort study indicate that the implantation of autologous spongious bone chips harvested during the decompression procedure is a useful and cheap alternative to an intervertebral cage in patients with degenerative pseudospondylolisthesis.

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