A new concept of motion preservation surgery of the cervical spine: PEEK rods for the posterior cervical region

2020 ◽  
Vol 31 (4) ◽  
pp. 235-251
Author(s):  
Ahmet Levent Aydin ◽  
Mehdi Sasani ◽  
Deniz Ufuk Erbulut ◽  
Tunc Oktenoglu ◽  
Ali Fahir Ozer
Keyword(s):  
Considerable Increase ◽  
Sagittal Plane ◽  
Cervical Vertebra ◽  
Cervical Region ◽  
Posterior Stabilization ◽  
Element Analysis ◽  
Motion Preservation ◽  
Peek Rods ◽  
Rod System ◽  
Different Diameters

BACKGROUND: Laminectomy may cause kyphotic postoperative deformity in the cervical region leading to segmental instability over time. Laminoplasty may be an alternative procedure to laminectomy, as it protects the spine against post-laminectomy kyphosis; however, similar to laminectomy, laminoplasty may cause sagittal plane deformities by destructing or weakening the dorsal tension band. OBJECTIVE: Using finite element analysis (FE), we attempted to determine whether a posterior motion preservation system (PEEK posterior rod system concept) could overcome the postoperative complications of laminectomy and laminoplasty and eliminate the side effects of rigid posterior stabilization in the cervical region. METHODS: We compared PEEK rods in four different diameters with a titanium rod for posterior cervical fixation. The present study may lead to motion preservation systems of the cervical vertebra. RESULTS: When PEEK rod is compared with titanium rod, considerable increase in range of motion is observed. CONCLUSIONS: PEEK rod-lateral mass screw instrumentation systems may be useful in motion preservation surgery of the posterior cervical region.

scholarly journals Biomechanical Effects of Polyetheretherketone and Titanium Rods in Transforaminal Lumbar Interbody Fusion: A Finite Element Analysis

2021 ◽  
Author(s):  
Jie Li ◽  
Shuai Cao ◽  
Jie Wang ◽  
Gaoyang Zong ◽  
Hao Qiao ◽  
...  
Keyword(s):  
Finite Element ◽  
Bone Graft ◽  
Interbody Fusion ◽  
Transforaminal Lumbar Interbody Fusion ◽  
Lumbar Interbody Fusion ◽  
Element Analysis ◽  
Positive Role ◽  
Biomechanical Behavior ◽  
Peek Rods ◽  
Rod System

Abstract Background: Currently, the comprehensive biomechanical evaluation of polyetheretherketone (PEEK) rods in transforaminal lumbar interbody fusion (TLIF) is limited. The purpose of this study was to compare the biomechanical differences between titanium alloy (Ti) rods and PEEK rods in TLIF. Methods: L3-5 lumbar models were developed using the finite element method. Four surgical models of TLIF were constructed by simulating different fusion methods and rods: cage fusion with Ti rods, cage fusion with PEEK rods, bone graft alone with Ti rods, and bone graft alone with PEEK rods. The range of motion (ROM) and stress distribution of the surgical and adjacent segments were then compared. Results: Compared to the Ti rods, the PEEK rods increased the ROM by 0.7–20% at the L4/5 segment and decreased the ROM by 0.8–15.1% at the L3/4 segment. The disc stresses at the L3/4 level were similar among the surgical models (0.79–1.80 MPa). The peak stresses of the screws, rods, and bone-screw interfaces in the PEEK rod models were 0–1.2 times, 1.6–4.4 times, and 0–1.4 times lower than those of the Ti rod models, respectively. PEEK rods increased the average strain of the bone graft by 0.5–61.6% and the stresses of the cage by 0.9–44.1% and endplates by 2.1–52.9%. Conclusion: In TLIF, PEEK rods played a positive role in restoring the ROM. They also increased the strain of the bone graft, stresses of the endplates and cages, and the risk of rod fracture and reduced the stress of the screw-rod system. Bone grafts alone combined with PEEK rods had acceptable biomechanical behavior in TLIF.

scholarly journals Computational and experimental mechanical performance of a new everolimus-eluting stent purpose-built for left main interventions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Saurabhi Samant ◽  
Wei Wu ◽  
Shijia Zhao ◽  
Behram Khan ◽  
Mohammadali Sharzehee ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Mechanical Performance ◽  
Experimental Studies ◽  
Patient Specific ◽  
Wall Structure ◽  
Left Main ◽  
Element Analysis ◽  
Stent Expansion ◽  
Radial Strength ◽  
Different Diameters

AbstractLeft main (LM) coronary artery bifurcation stenting is a challenging topic due to the distinct anatomy and wall structure of LM. In this work, we investigated computationally and experimentally the mechanical performance of a novel everolimus-eluting stent (SYNERGY MEGATRON) purpose-built for interventions to large proximal coronary segments, including LM. MEGATRON stent has been purposefully designed to sustain its structural integrity at higher expansion diameters and to provide optimal lumen coverage. Four patient-specific LM geometries were 3D reconstructed and stented computationally with finite element analysis in a well-validated computational stent simulation platform under different homogeneous and heterogeneous plaque conditions. Four different everolimus-eluting stent designs (9-peak prototype MEGATRON, 10-peak prototype MEGATRON, 12-peak MEGATRON, and SYNERGY) were deployed computationally in all bifurcation geometries at three different diameters (i.e., 3.5, 4.5, and 5.0 mm). The stent designs were also expanded experimentally from 3.5 to 5.0 mm (blind analysis). Stent morphometric and biomechanical indices were calculated in the computational and experimental studies. In the computational studies the 12-peak MEGATRON exhibited significantly greater expansion, better scaffolding, smaller vessel prolapse, and greater radial strength (expressed as normalized hoop force) than the 9-peak MEGATRON, 10-peak MEGATRON, or SYNERGY (p < 0.05). Larger stent expansion diameters had significantly better radial strength and worse scaffolding than smaller stent diameters (p < 0.001). Computational stenting showed comparable scaffolding and radial strength with experimental stenting. 12-peak MEGATRON exhibited better mechanical performance than the 9-peak MEGATRON, 10-peak MEGATRON, or SYNERGY. Patient-specific computational LM stenting simulations can accurately reproduce experimental stent testing, providing an attractive framework for cost- and time-effective stent research and development.

scholarly journals Retrieval analysis of PEEK rods for posterior fusion and motion preservation

2013 ◽  
Vol 22 (12) ◽  
pp. 2752-2759 ◽  
Author(s):  
Steven M. Kurtz ◽  
Todd H. Lanman ◽  
Genymphas Higgs ◽  
Daniel W. MacDonald ◽  
Sigurd H. Berven ◽  
...  
Keyword(s):  
Posterior Fusion ◽  
Motion Preservation ◽  
Retrieval Analysis ◽  
Peek Rods

Fatigue surviving, fracture resistance, shear stress and finite element analysis of glass fiber posts with different diameters

2015 ◽  
Vol 43 ◽  
pp. 69-77 ◽  
Author(s):  
Vinícius Felipe Wandscher ◽  
César Dalmolin Bergoli ◽  
Ariele Freitas de Oliveira ◽  
Osvaldo Bazzan Kaizer ◽  
Alexandre Luiz Souto Borges ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shear Stress ◽  
Glass Fiber ◽  
Fracture Resistance ◽  
Element Analysis ◽  
Fiber Posts ◽  
Glass Fiber Posts ◽  
Different Diameters

scholarly journals A feather cyst causing vertebral bone lysis and spinal cord compression in a Lohmann Brown layer

2020 ◽  
Vol 91 ◽  
Author(s):  
Alaster Samkange ◽  
Borden Mushonga ◽  
Erick Kandiwa ◽  
Alec S. Bishi ◽  
Basiamisi V.E. Segwagwe ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Cervical Spinal Cord ◽  
Cervical Vertebra ◽  
Cord Compression ◽  
Cervical Region ◽  
Subsequent Growth ◽  
Spinal Cord Segment ◽  
Normal Diameter ◽  
Bone Lysis ◽  
Exerted Pressure

A feather cyst in the cervical region which, through complications of inward growth, resulted in compression of the cervical spinal cord of a Lohmann Brown layer is described. It is postulated that expansion of the cyst exerted pressure on the adjacent cervical vertebra and through bone lysis created an opening through which the cyst protruded, thereby exerting pressure on the spinal cord. The affected spinal cord segment was reduced to a fifth of its normal diameter. The bird most likely died of starvation because of limb and neck paralysis and disorientation. Although the cause of the feather cyst was not conclusively identified, moulting and trauma could have triggered its formation and subsequent growth.

scholarly journals Eustachian tube diverticulum chondroids and neck abscessation in a case of Streptococcus equi subsp. equi : clinical communication

2007 ◽  
Vol 78 (3) ◽  
Author(s):  
C. Furniss ◽  
A. Carstens ◽  
I. Cilliers
Keyword(s):  
Eustachian Tube ◽  
Spinous Process ◽  
Cervical Vertebra ◽  
Cervical Region ◽  
Carrier Status ◽  
Clinical Communication ◽  
Negative Culture ◽  
Streptococcus Equi ◽  
Scalpel Blade ◽  
The Right

A 12-year-old, grey, crossbred pony mare was presented with a swelling in the neck over the area of the 2nd cervical vertebra (C2), which was found to be painful on palpation. The neck was held stiffly. Radiography of the cervical region showed a focal area of increased radio-opacity over the dorsal, caudal and lateral aspect of the dorsal spinous process of C2. Ultrasound confirmed the presence of a hypoechoic area approximately 15 cm in diameter superimposed over the dorsal spinous process of C2. An aspirate was taken of the mass, which revealed purulent exudate confirming the diagnosis of an abscess. The abscess was lanced with a scalpel blade and samples of the purulent material revealed a pure culture of Streptococcus equi subsp. equi. The guttural pouches (Eustachian tube diverticulae (ETD)) were then evaluated endoscopically and multiple chondroids were seen filling most of the right ETD. Surgery was subsequently performed and 189 chondroids were removed via a right-sided hyovertebrotomy. The ETDs were flushed and penicillin installed into both ETDs on 3 different occasions via a catheter introduced using a fibre optic scope. This procedure was repeated until a negative culture status was achieved in order to eliminate the carrier status.

Magnetic Resonance Imaging of Patients with Cervicogenic Headache

Cephalalgia ◽  
2003 ◽  
Vol 23 (8) ◽  
pp. 842-845 ◽  
Author(s):  
O Coskun ◽  
S Ucler ◽  
B Karakurum ◽  
HT Atasoy ◽  
T Yildirim ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Cervical Spine ◽  
Cervical Vertebra ◽  
Cervicogenic Headache ◽  
Cervical Region ◽  
Pathological Findings ◽  
Mri Imaging ◽  
Resonance Imaging ◽  
Nerve Roots ◽  
Adequate Method

Cervicogenic headache (CH) is a syndrome which is postulated to originate from nociceptive structures in the neck or head. The anatomical neck or head structures that are responsible for the pain in CH have not been clearly identified, but the pain in these patients probably originates from the structures of the cervical spine. In this study, cervical MRI were studied in 22 patients with cervicogenic headache and 20 control patients who did not have any disease which may effect the bone and muscle structures of cervical region. MRI imaging of cervical vertebra showed a disc bulging in 10 (45.4%) out of 22 patients with CH and in 9 (45.0%) of 20 controls ( P > 0.05). The distribution of pathological lesions in patients and controls were not significantly different ( P > 0.05). As a result, MRI may not be an adequate method to detect pathological findings underlying the aetiology of CH such as nerve roots, intervertebral joints and periosteum.

Effects of Gun Tube Profile and Sabot on Stresses and Velocity of Long Rod Penetrator

2005 ◽  
Vol 9 ◽  
pp. 109-116 ◽  
Author(s):  
J.B. Kim
Keyword(s):  
Three Dimensional ◽  
Von Mises Stress ◽  
Analysis Method ◽  
Type B ◽  
Element Analysis ◽  
Dynamic Finite Element Analysis ◽  
Curved Tube ◽  
Rod System ◽  
Long Rod ◽  
Von Mises

The paper describes the combined influences of the forward sabot diameter, sabot modulus, and L/D on the stress of the projectile rod traveling in the gun tube. Three types of gun tube profile were simulated. The first profile is perfectly straight. The second profile is monotonously curved tube only by gravity loads (Type A). The third is a changeful curved tube by gravity loads with imagined as-manufactures (Type B). Three-dimensional dynamic finite element analysis method was used for the sabot/rod system transiting in a gun tube. Numerical simulation results showed that the maximum von Mises stress due to in-bore behavior of the sabot/rod system could be decreased by changing the forward sabot diameter in a type B tube. The effect of tube centerline profile on the stress of the rod was analyzed for the conditions mentioned above. The von Mises stress of the rod in the changeful curved tube is as much as 10% higher than that in the straight or monotonously curved tube.

Biomechanical Assessment of a PEEK Rod System for Semi-Rigid Fixation of Lumbar Fusion Constructs

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Matthew F. Gornet ◽  
Frank W. Chan ◽  
John C. Coleman ◽  
Brian Murrell ◽  
Russ P. Nockels ◽  
...  
Keyword(s):  
Lumbar Fusion ◽  
Dynamic Performance ◽  
Load Sharing ◽  
Axial Rotation ◽  
Rigid Fixation ◽  
Peek Rods ◽  
Significant Difference ◽  
Flexion Extension ◽  
Rod System

The concept of semi-rigid fixation (SRF) has driven the development of spinal implants that utilize nonmetallic materials and novel rod geometries in an effort to promote fusion via a balance of stability, intra- and inter-level load sharing, and durability. The purpose of this study was to characterize the mechanical and biomechanical properties of a pedicle screw-based polyetheretherketone (PEEK) SRF system for the lumbar spine to compare its kinematic, structural, and durability performance profile against that of traditional lumbar fusion systems. Performance of the SRF system was characterized using a validated spectrum of experimental, computational, and in vitro testing. Finite element models were first used to optimize the size and shape of the polymeric rods and bound their performance parameters. Subsequently, benchtop tests determined the static and dynamic performance threshold of PEEK rods in relevant loading modes (flexion-extension (F/E), axial rotation (AR), and lateral bending (LB)). Numerical analyses evaluated the amount of anteroposterior column load sharing provided by both metallic and PEEK rods. Finally, a cadaveric spine simulator was used to determine the level of stability that PEEK rods provide. Under physiological loading conditions, a 6.35 mm nominal diameter oval PEEK rod construct unloads the bone-screw interface and increases anterior column load (approx. 75% anterior, 25% posterior) when compared to titanium (Ti) rod constructs. The PEEK construct’s stiffness demonstrated a value lower than that of all the metallic rod systems, regardless of diameter or metallic composition (78% < 5.5 mm Ti; 66% < 4.5 mm Ti; 38% < 3.6 mm Ti). The endurance limit of the PEEK construct was comparable to that of clinically successful metallic rod systems (135N at 5 × 106 cycles). Compared to the intact state, cadaveric spines implanted with PEEK constructs demonstrated a significant reduction of range of motion in all three loading directions (> 80% reduction in F/E, p < 0.001; > 70% reduction in LB, p < 0.001; > 54% reduction in AR, p < 0.001). There was no statistically significant difference in the stability provided by the PEEK rods and titanium rods in any mode (p = 0.769 for F/E; p = 0.085 for LB; p = 0.633 for AR). The CD HORIZON® LEGACY™ PEEK Rod System provided intervertebral stability comparable to currently marketed titanium lumbar fusion constructs. PEEK rods also more closely approximated the physiologic anteroposterior column load sharing compared to results with titanium rods. The durability, stability, strength, and biomechanical profile of PEEK rods were demonstrated and the potential advantages of SRF were highlighted.

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