Comparison of Pedicle Screw Loosening Mechanisms and the Effect on Fixation Strength

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Hedayeh Mehmanparast ◽  
Yvan Petit ◽  
Jean-Marc Mac-Thiong
Keyword(s):  
Pedicle Screw ◽  
Lumbar Vertebrae ◽  
Pedicle Screws ◽  
Pedicle Screw Fixation ◽  
Fixation Strength ◽  
Screw Loosening ◽  
Spinal Fixation ◽  
Bending Load ◽  
Biomechanical Evaluation ◽  
Pedicle Screw Loosening

Screw loosening is a common complication in spinal fixation using pedicle screws which may lead to loss of correction and revision surgery. The mechanisms of pedicle screw loosening are not well understood. The purpose of this study was to compare the pedicle screw pullout force and stiffness subsequent or not to multidirectional cyclic bending load (toggling). Pedicle screws inserted into porcine lumbar vertebrae underwent toggling in craniocaudal (CC), mediolateral (ML) directions, and no toggling (NT) before pullout. This study suggests that toggling and in particular CC toggling should be included in biomechanical evaluation of pedicle screw fixation strength.

INVESTIGATION INTO WHETHER OR NOT PMMA BONE CEMENT TRANSPEDICULAR SCREW AUGMENTATION STABILIZES PEDICLE SCREW LOOSENING

2019 ◽  
Vol 19 (02) ◽  
pp. 1940024
Author(s):  
PO-YI LIU ◽  
SHENG-CHIH LIN ◽  
PO-LIANG LAI ◽  
CHUN-LI LIN
Keyword(s):  
Bone Cement ◽  
Pedicle Screw ◽  
Fatigue Resistance ◽  
Fatigue Testing ◽  
Pedicle Screw Fixation ◽  
Screw Loosening ◽  
General Technique ◽  
Screw Augmentation ◽  
Pmma Bone Cement ◽  
Pedicle Screw Loosening

Pedicle screw loosening at the bone–screw interface is the main complication in pedicle screw fixation. The transpedicular polymethylmethacrylate screw augmentation technique has recently become the general technique used to re-operatively overcome pedicle screw loosening. This study investigates the fatigue resistance of PMMA bone cement augmentation. Twenty-seven porcine thoracic vertebral bodies were collected. The BMD was measured using dual X-ray absorptiometry. Each vertebral body was instrumented with one pedicle screw and mounted in a material testing system. Fatigue testing was performed by implementing a cranio-caudal sinusoidal, cyclic (5[Formula: see text]Hz) load. This study shows that transpedicular pedicle screw augmentation with PMMA exhibits similar fatigue resistance as traditional pedicle screw implantation. However, in histomophometrical analysis, the transpedicular pedicle screw augmentation with PMMA has greater anti-deformation capacity than traditional pedicle screw implantation. Transpedicular pedicle screw augmentation with PMMA improves more screw holding power to prevent pedicle screw loosening.

scholarly journals Balancing Rigidity and Safety of Pedicle Screw Fixation via a Novel Expansion Mechanism in a Severely Osteoporotic Model

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Thomas M. Shea ◽  
James J. Doulgeris ◽  
Sabrina A. Gonzalez-Blohm ◽  
William E. Lee ◽  
Kamran Aghayev ◽  
...  
Keyword(s):  
Cortical Bone ◽  
Pedicle Screw ◽  
Pedicle Screws ◽  
Pedicle Screw Fixation ◽  
Cortical Layer ◽  
Fixation Strength ◽  
Osteoporotic Bone ◽  
Pullout Strength ◽  
Initial Fixation ◽  
Increased Risk

Many successful attempts to increase pullout strength of pedicle screws in osteoporotic bone have been accompanied with an increased risk of catastrophic damage to the patient. To avoid this, a single-armed expansive pedicle screw was designed to increase fixation strength while controlling postfailure damage away from the nerves surrounding the pedicle. The screw was then subsequently tested in two severely osteoporotic models: one representing trabecular bone (with and without the presence of polymethylmethacrylate) and the other representing a combination of trabecular and cortical bone. Maximum pullout strength, stiffness, energy to failure, energy to removal, and size of the resulting block damage were statistically compared among conditions. While expandable pedicle screws produced maximum pullout forces less than or comparable to standard screws, they required a higher amount of energy to be fully removed from both models. Furthermore, damage to the cortical layer in the composite test blocks was smaller in all measured directions for tests involving expandable pedicle screws than those involving standard pedicle screws. This indicates that while initial fixation may not differ in the presence of cortical bone, the expandable pedicle screw offers an increased level of postfailure stability and safety to patients awaiting revision surgery.

scholarly journals Cement leakage in pedicle screw augmentation: a prospective analysis of 98 patients and 474 augmented pedicle screws

2016 ◽  
Vol 25 (1) ◽  
pp. 103-109 ◽  
Author(s):  
Jan U. Mueller ◽  
Joerg Baldauf ◽  
Sascha Marx ◽  
Michael Kirsch ◽  
Henry W. S. Schroeder ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Screw Fixation ◽  
Pedicle Screws ◽  
High Volume ◽  
Cement Leakage ◽  
Pedicle Screw Fixation ◽  
Screw Loosening ◽  
Pedicle Screw Placement ◽  
Screw Augmentation ◽  
Cement Embolism

OBJECTIVE Loosening and pullout of pedicle screws are well-known problems in pedicle screw fixation surgery. Augmentation of pedicle screws with bone cement, first described as early as 1975, increases the pedicle-screw interface and pullout force in osteoporotic vertebrae. The aim of the present study was to identify cement leakage and pulmonary embolism rates in a large prospective single-center series of pedicle screw augmentations. METHODS All patients who underwent cement-augmented pedicle screw placement between May 2006 and October 2010 at the authors' institution were included in this prospective cohort study. Perivertebral cement leakage and pulmonary cement embolism were evaluated with a CT scan of the area of operation and with a radiograph of the chest, respectively. RESULTS A total of 98 patients underwent placement of cement-augmented pedicle screws; 474 augmented screws were inserted in 237 vertebrae. No symptomatic perivertebral cement leakage or symptomatic pulmonary cement embolism was observed, but asymptomatic perivertebral cement leakage was seen in 88 patients (93.6%) and in 165 augmented vertebrae (73.3%). Cement leakage most often occurred in the perivertebral venous system. Clinically asymptomatic pulmonary cement embolism was found in 4 patients (4.1%). CONCLUSIONS Perivertebral cement leakage often occurs in pedicle screw augmentation, but in most cases, it is clinically asymptomatic. Cement augmentation should be performed under continuous fluoroscopy to avoid high-volume leakage. Alternative strategies, such as use of expandable screws, should be examined in more detail for patients at high risk of screw loosening.

scholarly journals Broken lumbar pedicle screw – a short report

2017 ◽  
Vol 31 (4) ◽  
pp. 572-574
Author(s):  
Ashish Kumar Dwivedi ◽  
Rashim Kataria ◽  
Virendra Deo Sinha
Keyword(s):  
Pedicle Screw ◽  
Surgical Procedure ◽  
Screw Fixation ◽  
Rare Complication ◽  
Pedicle Screws ◽  
Pedicle Screw Fixation ◽  
Short Report ◽  
Spinal Fixation ◽  
Fixation Technique ◽  
The Common

Abstract Spinal fixation is one of the common surgical procedure performed by spine surgeons. Among the various spinal fixation technique, pedicle screw fixation is of paramount importance especially when instability is in dorsolumbar and sacral region of spine. Like any surgical procedure, pedicle screw fixation is not devoid of complications. Broken pedicle screws are one of the rare complication of this procedure with a great challenge to deal with such situation. We are reporting one of the rare complication of pedicle screw fixation with literature review and our philosophy to deal such complication.

SEGMENTAL POLYMETHYLMETHACRYLATE-AUGMENTED PEDICLE SCREW FIXATION IN PATIENTS WITH BONE SOFTENING CAUSED BY OSTEOPOROSIS AND METASTATIC TUMOR INVOLVEMENT

Neurosurgery ◽  
2007 ◽  
Vol 61 (3) ◽  
pp. 531-538 ◽  
Author(s):  
Bruce M. Frankel ◽  
Tanya Jones ◽  
Chiang Wang
Keyword(s):  
Pedicle Screw ◽  
Screw Fixation ◽  
Degenerative Spondylolisthesis ◽  
Spinal Instrumentation ◽  
Pedicle Screw Fixation ◽  
Screw Loosening ◽  
Cell Lung Carcinoma ◽  
Tumor Involvement ◽  
Pedicle Screw Loosening ◽  
Cement Extravasation

Abstract OBJECTIVE Instrumentation of the osteoporotic spine may result in bone failure because of pedicle screw loosening and pullout. A clinical evaluation of a novel fenestrated bone tap used in pedicle screw augmentation was performed to determine the performance and safety of this technique. METHODS Over a 2.5-year period, the clinical and radiographic results of 119 consecutive patients who underwent instrumented arthrodesis were reviewed. Of these patients, 23 had bone softening secondary to osteoporosis and/or metastatic spinal tumor involvement. These patients underwent surgical decompression and spinal instrumentation. RESULTS Six patients (26%) had metastatic spine disease (squamous cell lung carcinoma, renal cell carcinoma, bladder carcinoma, breast, prostate, and uterine adenocarcinoma); five patients (22%) had a degenerative spondylolisthesis; and 12 patients (52%) had burst fractures, eight as a result of benign causes and four as a result of metastatic disease. Four (17%) patients underwent revision surgery of previous pedicle screw failure resulting from bone softening and pseudarthrosis. A total of 98 levels were fused using 158 polymethylmethacrylate-augmented screws. None of the patients experienced operative death, myocardial infarction, hypoxemia, intraoperative hypotension, radiculopathy, or myelopathy. Asymptomatic anterior cement extravasation was observed in nine patients (39%). There was one asymptomatic polymethylmethacrylate pulmonary embolus and one wound infection. There was no significant relationship between cement extravasation and the quantity used, levels augmented, or location (P > 0.05). There were no construct failures. CONCLUSION Polymethylmethacrylate-augmented pedicle screw fixation reduces the likelihood of pedicle screw loosening and pullout in patients with osteoporosis requiring instrumented arthrodesis.

scholarly journals Intraoperative biomechanics of lumbar pedicle screw loosening following successful arthrodesis

2016 ◽  
Author(s):  
Hope B. Pearson ◽  
Christopher J. Dobbs ◽  
Eric Grantham ◽  
Glen L. Niebur ◽  
James L. Chappuis ◽  
...  
Keyword(s):  
Back Pain ◽  
Pedicle Screw ◽  
Statistical Power ◽  
Lumbar Fusion ◽  
Pedicle Screws ◽  
Screw Loosening ◽  
Screw Insertion ◽  
Screw Misplacement ◽  
Lumbar Spinal ◽  
Pedicle Screw Loosening

AbstractPedicle screw loosening has been implicated in recurrent back pain after lumbar spinal fusion, but the degree of loosening has not been systematically quantified in patients. Instrumentation removal is an option for patients with successful arthrodesis, but remains controversial. Here, we quantified pedicle screw loosening by measuring screw insertion and/or removal torque at high statistical power (β = 0.98) in N = 108 patients who experienced pain recurrence despite successful fusion after posterior instrumented lumbar fusion with anterior lumbar interbody fusion (L2-S1). Between implantation and removal, pedicle screw torque was reduced by 58%, indicating significant loosening over time. Loosening was greater in screws with evoked EMG threshold under 11 mA, indicative of screw misplacement. A theoretical stress analysis revealed increased local stresses at the screw interface in pedicles with decreased difference in pedicle thickness and screw diameter. Loosening was greatest in vertebrae at the extremities of the fused segments, but was significantly lower in segments with one level of fusion than in those with two or more.Clinical significanceThese data indicate that pedicle screws can loosen significantly in patients with recurrent back pain and warrant further research into methods to reduce the incidence of screw loosening and to understand the risks and potential benefits of instrumentation removal.

scholarly journals Computed tomography Hounsfield unit–based prediction of pedicle screw loosening after surgery for degenerative lumbar spine disease

2020 ◽  
Vol 32 (5) ◽  
pp. 716-721
Author(s):  
Da Zou ◽  
Aikeremujiang Muheremu ◽  
Zhuoran Sun ◽  
Woquan Zhong ◽  
Shuai Jiang ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Regression Analysis ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Hounsfield Unit ◽  
Pedicle Screw Fixation ◽  
Screw Loosening ◽  
Pedicle Screw Loosening ◽  
Spine Disease ◽  
Lumbar Pedicle

OBJECTIVEThe authors investigated the relation between Hounsfield unit (HU) values measured on CT and the risk of pedicle screw loosening in patients who underwent lumbar pedicle screw fixation for degenerative lumbar spine disease.METHODSPatients who were treated with lumbar pedicle screw fixation between July 2011 and December 2015 at the authors’ department were reviewed. Age, sex, BMI, smoking and diabetes histories, range of fixation, and fusion method were recorded as the basic patient information. The HU values for lumbar bone mineral density (BMD) for the L1, L2, L3, and L4 vertebra were measured on CT scans. Logistic regression analysis was used to identify the independent influencing factors of pedicle screw loosening.RESULTSA total of 503 patients were included in the final analysis. The pedicle screw loosening rate at the 12-month follow-up was 30.0% (151 of 503 patients). There were no significant differences in sex, BMI, or histories of smoking and diabetes between the patients with (loosening group) and those without (nonloosening group) screw loosening (p > 0.05). The mean HU value of L1–4 was lower in the loosening group than the nonloosening group (106.3 ± 33.9 vs 132.6 ± 42.9, p < 0.001). In logistic regression analysis, being male (OR 2.065; 95% CI 1.242–3.433), HU value (OR 0.977; 95% CI 0.970–0.985), length of fixation (OR 3.616; 95% CI 2.617–4.996), and fixation to S1 (OR 1.699; 95% CI 1.039–2.777) were the independent influencing factors for screw loosening.CONCLUSIONSHU value measured on CT was an independent predictor for pedicle screw loosening, and lower HU value was significantly correlated with higher risk of screw loosening.

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