scholarly journals Hybrid Strategy of Cervical Artificial Disc and Intervertebral Cage – Biomechanical Effects on the Adjacent Tissues and Implants

2020 ◽  
Author(s):  
Tzu-Tsao Chung ◽  
Dueng-Yuan Hueng ◽  
Chi-Pin Hsu ◽  
Chun-Ming Chen ◽  
Shang-Chih Lin
Keyword(s):  
Element Model ◽  
Adjacent Segment Degeneration ◽  
Adjacent Segment ◽  
Peek Cage ◽  
Artificial Disc ◽  
Hybrid Surgery ◽  
Hybrid Strategy ◽  
Intervertebral Cage ◽  
Adjacent Segments ◽  
Nonlinear Finite Element Model

Abstract Background: Adjacent segment degeneration (ASD) is a concern in multi-level ACDF surgery. Hybrid surgery with C-ADR and ACDF are an alternative treatment to reduce the level of increased rigidity, but biomechanical differences between strategies using one C-ADR and two ACDFs have not been thoroughly investigated.Methods: To evaluate the placement-related effects of using one cervical artificial disc replacement (C-ADR) and two anterior cervical discectomy and fusion (ACDF) on tissue responses and implant behavior. A nonlinear finite element model from the C2 to the T1 vertebrae was developed. Ligament interconnection, follower loads, and weight compression were used to simulate cervical flexion. Within the C4-C7 segments, two placements of one C-ADR and two ACDFs were arranged: PAP (peek cage, artificial disc, and peek cage) and APP.Results: Both PAP and APP consistently induced kinematic and mechanical redistribution to adjacent segments. The C-ADR served as a buffer of the compensated motion and stress from the ACDF segments. The motion and stress of the cranial C2-C3 and C3-C4 segments were greater for the PAP than the APP constructs. However, the caudal C7-T1 segment of the APP construct was more flexed and stressed. Serially stacked cages of the APP placement increased bone-cage stresses, potentially inducing subsidence and loosening. The sandwiched C-ADR of the PAP construct accommodated the compensated motion and stress from the adjacent ACDFs more than the APP construct.Conclusions: The PAP and APP placements cause more severe ASD progression at the cranial and caudal segments, respectively. The PAP placement is preferred for concerns regarding ACDF and postoperative degeneration of caudal segments. The APP placement is recommended when C-ADR failure and ASD progression are considered.

Impact of Cervical Artificial Disc Implantation on the Biomechanical Function of Adjacent Segments

2013 ◽  
Vol 748 ◽  
pp. 358-364
Author(s):  
Wen Zhi Zhao ◽  
Bin Li ◽  
Bing Zhi Chen ◽  
Sheng Wei He ◽  
Jin Su ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Intervertebral Disc ◽  
Interbody Fusion ◽  
Element Model ◽  
Cervical Disc ◽  
Adjacent Segment ◽  
Artificial Disc ◽  
Range Of Movement ◽  
Fusion Surgery ◽  
Adjacent Segments

The range of movement(ROM) of adjacent segments and the change of intervertebral disc stress after implanting artificial cervical disc are investigated. The contact problem for bio-modeling is introduced. A normal cervical spine finite element model is proposed. The bone graft and fusion between C5 and C6 and C5/6 artificial disc implantation were simulated. The range of movement on adjacent segment and the change of intervertebral disc’s stress in such two cases are analyzed. Computational results show that the model includes the ligaments, joint capsule and other soft tissue structures, which is real, fine and high accuracy. When the adjacent intervertebral ROM was increased after interbody fusion surgery, the stress of corresponding intervertebral disc was increased obviously and the stress of upper segment of nucleus pulposus and annulus fibrosus were also increased about 70% ,besides the next-bit segments was increased about 40%. There were no differences among cervical spine ROM except extension (p> 0.05) after the implantation of artificial disc, and the stress on adjacent segments was increased less than 10%. The implantation of artificial cervical disc can release the stress on adjacent segments in a certain extent, and resume cervical activities at the same time.

Relationship between biomechanical changes at adjacent segments and number of fused bone grafts in multilevel cervical fusions: a finite element investigation

2014 ◽  
Vol 20 (1) ◽  
pp. 22-29 ◽  
Author(s):  
Mozammil Hussain ◽  
Ahmad Nassr ◽  
Raghu N. Natarajan ◽  
Howard S. An ◽  
Gunnar B. J. Andersson
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Bone Grafts ◽  
Adjacent Segment Degeneration ◽  
Adjacent Segment ◽  
Hybrid Technique ◽  
Fusion Construct ◽  
Biomechanical Changes ◽  
Lower Magnitude ◽  
Adjacent Segments

Object Biomechanical studies have shown that anterior cervical fusion construct stiffness and arthrodesis rates vary with different reconstruction techniques; however, the behavior of the adjacent segments in the setting of different procedures is poorly understood. This study was designed to investigate the adjacent-segment biomechanics after 3 different anterior cervical decompression and fusion techniques, including 3-level discectomy and fusion, 2-level corpectomy and fusion, and a corpectomy-discectomy hybrid technique. The authors hypothesized that biomechanical changes at the segments immediately superior and inferior to the multilevel fusion would be inversely proportional to the number of fused bone grafts and that these changes would be related to the type of fusion technique. Methods A previously validated 3D finite element model of an intact C3–T1 segment was used. Three C4–7 fusion models were built from this intact model by varying the number of bone grafts used to span the decompression: a 1-graft model (2-level corpectomy), a 2-graft model (C-5 corpectomy and C6–7 discectomy), and a 3-graft model (3-level discectomy). The corpectomy and discectomy models were also previously validated and compared well with the literature findings. Range of motion, disc stresses, and posterior facet loads at the segments superior (C3–4) and inferior (C7–T1) to the fusion construct were assessed. Results Motion, disc stresses, and posterior facet loads generally increased at both of the adjacent segments in relation to the intact model. Greater biomechanical changes were noted in the superior C3–4 segment than in the inferior C7–T1 segment. Increasing the number of bone grafts from 1 to 2 and from 2 to 3 was associated with a lower magnitude of biomechanical changes at the adjacent segments. Conclusions At segments adjacent to the fusion level, biomechanical changes are not limited solely to the discs, but also propagate to the posterior facets. These changes in discs and posterior facets were found to be lower for discectomy than for corpectomy, thereby supporting the current study hypothesis of inverse relationship between the adjacent-segment variations and the number of fused bone grafts. Such changes may go on to influence the likelihood of adjacent-segment degeneration accordingly. Further studies are warranted to identify the causes and true impact of these observed changes.

scholarly journals TELD with limited foraminoplasty has potential biomechanical advantages over TELD with large annuloplasty: an in-silico study

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Jingchi Li ◽  
Chen Xu ◽  
Xiaoyu Zhang ◽  
Zhipeng Xi ◽  
Mengnan Liu ◽  
...  
Keyword(s):  
Risk Factors ◽  
Postoperative Complications ◽  
Poor Prognosis ◽  
Adjacent Segment Degeneration ◽  
Iatrogenic Injury ◽  
Adjacent Segment ◽  
Fe Model ◽  
High Grade ◽  
Endoscopic Lumbar Discectomy ◽  
Adjacent Segments

Abstract Background Facetectomy, an important procedure in the in–out and out–in techniques of transforaminal endoscopic lumbar discectomy (TELD), is related to the deterioration of the postoperative biomechanical environment and poor prognosis. Facetectomy may be avoided in TELD with large annuloplasty, but iatrogenic injury of the annulus and a high grade of nucleotomy have been reported as risk factors influencing poor prognosis. These risk factors may be alleviated in TELD with limited foraminoplasty, and the grade of facetectomy in this surgery can be reduced by using an endoscopic dynamic drill. Methods An intact lumbo-sacral finite element (FE) model and the corresponding model with adjacent segment degeneration were constructed and validated to evaluate the risk of biomechanical deterioration and related postoperative complications of TELD with large annuloplasty and TELD with limited foraminoplasty. Changes in various biomechanical indicators were then computed to evaluate the risk of postoperative complications in the surgical segment. Results Compared with the intact FE models, the model of TELD with limited foraminoplasty demonstrated slight biomechanical deterioration, whereas the model of TELD with large annuloplasty revealed obvious biomechanical deterioration. Degenerative changes in adjacent segments magnified, rather than altered, the overall trends of biomechanical change. Conclusions TELD with limited foraminoplasty presents potential biomechanical advantages over TELD with large annuloplasty. Iatrogenic injury of the annulus and a high grade of nucleotomy are risk factors for postoperative biomechanical deterioration and complications of the surgical segment.

scholarly journals Additional decompression at adjacent segments leads to adjacent segment degeneration after PLIF

2013 ◽  
Vol 22 (8) ◽  
pp. 1877-1883 ◽  
Author(s):  
Masayuki Miyagi ◽  
Osamu Ikeda ◽  
Seiji Ohtori ◽  
Yoshikazu Tsuneizumi ◽  
Yukio Someya ◽  
...  
Keyword(s):  
Adjacent Segment Degeneration ◽  
Adjacent Segment ◽  
Adjacent Segments

Adjacent Segment Degeneration After Anterior Cervical Discectomy and Fusion With an Autologous Iliac Crest Graft: A Magnetic Resonance Imaging Study of 59 Patients With a Mean Follow-up of 27 Years

Neurosurgery ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. 799-807 ◽  
Author(s):  
Benedikt W Burkhardt ◽  
Andreas Simgen ◽  
Gudrun Wagenpfeil ◽  
Wolfgang Reith ◽  
Joachim M Oertel
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Adjacent Segment Degeneration ◽  
Disc Height ◽  
Adjacent Segment ◽  
Resonance Imaging ◽  
Physiological Aging ◽  
Repeat Procedure ◽  
Adjacent Segments

Abstract BACKGROUND Anterior cervical decompression and fusion (ACDF) is a widely accepted surgical technique for the treatment of degenerative disc disease. ACDF is associated with adjacent segment degeneration (ASD). OBJECTIVE To assess whether physiological aging of the spine would overcome ASD by comparing adjacent to adjoining segments more than 18 yr after ACDF. METHODS Magnetic resonance imaging of 59 (36 male, 23 female) patients who underwent ACDF was performed to assess degeneration. The mean follow-up was 27 yr (18-45 yr). Besides measuring the disc height, a 5-step grading system (segmental degeneration index [SDI]) including disc signal intensity, anterior and posterior disc protrusion, narrowing of the disc space, and foraminal stenosis was used to assess the grade of adjacent and adjoining segments. RESULTS The SDI of cranial and caudal adjacent segments was significantly higher compared to adjoining segments (P < .001). The disc height of cranial and caudal adjacent segments was significantly lower compared to adjoining segments (P < .001, P < .01). The SDI of adjacent segments in patients with repeat cervical procedure was significantly higher than in patients without repeat procedure (P = .02, P = .01). The disc height of the cranial adjacent segments in patients with repeat procedure was significantly lower than in patients without repeat procedure (P = .01). CONCLUSION The physiological aging of the cervical spine does not overcome ASD. The disc height and the SDI in adjacent segment are significantly worse compared to adjoining segments. Patients who underwent repeat procedure had even worse findings of disc height and SDI.

The Efficacy of Lumbar Hybrid Stabilization Using the DIAM to Delay Adjacent Segment Degeneration: An Intervention Comparison Study With a Minimum 2-Year Follow-up

2013 ◽  
Vol 73 (2) ◽  
pp. ons224-ons232 ◽  
Author(s):  
Chang-Hyun Lee ◽  
Seung-Jae Hyun ◽  
Ki-Jeong Kim ◽  
Tae-Ahn Jahng ◽  
Sang Hoon Yoon ◽  
...  
Keyword(s):  
Odds Ratio ◽  
Adjacent Segment Degeneration ◽  
Adjacent Segment ◽  
Comparison Study ◽  
Hybrid Surgery ◽  
Long Term Outcome ◽  
Hybrid Stabilization ◽  
Surgical Methods ◽  
Facet Joint Degeneration ◽  
Hybrid Group

Abstract BACKGROUND: Although posterior lumbar interbody fusion (PLIF) has a successful fusion rate, the long-term outcome of PLIF is occasionally below expectations because of adjacent segment degeneration (ASD). OBJECTIVE: To evaluate the ability of hybrid stabilization using DIAM (Device for Interspinous Assisted Motion) to delay ASD. METHODS: An intervention comparison study of 75 patients (hybrid, 25; PLIF, 50) was performed. The indications for hybrid stabilization were facet joint degeneration, Pfirrmann grade II to III, and stenosis at the rostral adjacent segment. The PLIF group consisted of patients matched for age, sex, and fusion. The hybrid stabilization procedure included traditional PLIF and DIAM installation at a superior adjacent segment. The outcomes were analyzed with a linear mixed model analysis. Conditional logistic regression was performed to calculate the odds ratio for the association of surgical methods. RESULTS: The hybrid group (24%) revealed fewer ASDs than the PLIF group (48%). Among ASDs, spondylolisthesis occurred more frequently in the PLIF group than the hybrid group. Hybrid surgery was significantly associated with ASD; the odds ratio for hybrid surgery was 0.28 compared with PLIF. Foraminal height of the PLIF group decreased more than the hybrid group (P = .01). Segmental mobility showed a greater increase in the PLIF group than the hybrid group (P = .04). However, the clinical outcomes did not show significant differences between the groups. CONCLUSION: Hybrid stabilization with DIAM and pedicle screws can be used for patients with facet degeneration at adjacent segments but should be further investigated.

A Computational Biomechanical Investigation of Posterior Dynamic Instrumentation: Combination of Dynamic Rod and Hinged (Dynamic) Screw

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Deniz U. Erbulut ◽  
Ali Kiapour ◽  
Tunc Oktenoglu ◽  
Ali F. Ozer ◽  
Vijay K. Goel
Keyword(s):  
Peak Stress ◽  
Adjacent Segment Degeneration ◽  
Dynamic Stabilization ◽  
Adjacent Segment ◽  
Fe Model ◽  
Rigid Fixation ◽  
Segmental Motion ◽  
Rigid Rod ◽  
Adjacent Segments

Currently, rigid fixation systems are the gold standard for degenerative disk disease treatment. Dynamic fixation systems have been proposed as alternatives for the treatment of a variety of spinal disorders. These systems address the main drawbacks of traditional rigid fixation systems, such as adjacent segment degeneration and instrumentation failure. Pedicle-screw-based dynamic stabilization (PDS) is one type of these alternative systems. The aim of this study was to simulate the biomechanical effect of a novel posterior dynamic stabilization system, which is comprised of dynamic (hinged) screws interconnected with a coiled, spring-based dynamic rod (DSDR), and compare it to semirigid (DSRR and RSRR) and rigid stabilization (RSRR) systems. A validated finite element (FE) model of L1-S1 was used to quantify the biomechanical parameters of the spine, such as range of motion, intradiskal pressure, stresses and facet loads after single-level instrumentation with different posterior stabilization systems. The results obtained from in vitro experimental intact and instrumented spines were used to validate the FE model, and the validated model was then used to compare the biomechanical effects of different fixation and stabilization constructs with intact under a hybrid loading protocol. The segmental motion at L4–L5 increased by 9.5% and 16.3% in flexion and left rotation, respectively, in DSDR with respect to the intact spine, whereas it was reduced by 6.4% and 10.9% in extension and left-bending loads, respectively. After instrumentation-induced intradiskal pressure at adjacent segments, L3-L4 and L5-S1 became less than the intact in dynamic rod constructs (DSDR and RSDR) except in the RSDR model in extension where the motion was higher than intact by 9.7% at L3-L4 and 11.3% at L5-S1. The facet loads were insignificant, not exceeding 12N in any of the instrumented cases in flexion. In extension, the facet load in DSDR case was similar to that in intact spine. The dynamic rod constructions (DSDR and RSDR) led to a lesser peak stress at screws compared with rigid rod constructions (DSRR and RSRR) in all loading cases. A dynamic construct consisting of a dynamic rod and a dynamic screw did protect the adjacent level from excessive motion.

scholarly journals Hybrid Strategy of Two-Level Cervical Artificial Disc and Intervertebral Cage

Medicine ◽  
2015 ◽  
Vol 94 (47) ◽  
pp. e2048 ◽  
Author(s):  
Tzu-Tsao Chung ◽  
Dueng-Yuan Hueng ◽  
Shang-Chih Lin
Keyword(s):  
Artificial Disc ◽  
Hybrid Strategy ◽  
Intervertebral Cage

Artificial Disc Versus Fusion: Effect on Three-Dimensional Dynamic In Vivo Cervical Spine Motion

2011 ◽  
Author(s):  
Colin P. McDonald ◽  
Michael J. McDonald ◽  
Nicole L. Ramo ◽  
Stephen W. Bartol ◽  
Michael J. Bey
Keyword(s):  
Cervical Spine ◽  
Three Dimensional ◽  
Adjacent Segment Degeneration ◽  
Cervical Disc ◽  
Adjacent Segment ◽  
Artificial Disc ◽  
Disc Disease ◽  
Adjacent Disc ◽  
Spine Motion

Intervertebral disc degeneration in the cervical spine is a common condition that often manifests as cervical disc disease, resulting in pain, motor weakness and sensory deficits. The most common surgical treatment strategy involves removal of the diseased disc and fusion of the adjacent vertebrae. Although fusion typically relieves symptoms at the surgical site, evidence of degeneration in the adjacent disc has been reported in 25–92% of patients [1,2]. It has been hypothesized that the progression of adjacent segment degeneration is a result of increased motion at the segments adjacent to the site of fusion [3]. As a response to this proposed mechanism of degeneration, artificial discs were designed with the goals of preserving motion at the operative site and maintaining normal motion in the adjacent segments. However, the extent to which normal adjacent segment motion is maintained in artificial disc patients compared to fusion patients remains unknown. Thus, the objective of this study was to compare the dynamic, three-dimensional (3D) motion of the cervical spine in fusion patients and artificial disc replacement patients.

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