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Scientific Reports Jun 2022This study aims to investigate the difference in physiological loading on the spine in three different motions (flexion-extension, lateral bending, and axial rotation)...
This study aims to investigate the difference in physiological loading on the spine in three different motions (flexion-extension, lateral bending, and axial rotation) between osteoporotic and normal spines, using finite element modelling. A three-dimensional finite element (FE) model centered on the lumbar spine was constructed. We applied two different material properties of osteoporotic and normal spines. For the FE analysis, three loading conditions (flexion-extension, lateral bending, and axial rotation) were applied. The von Mises stress was higher on the nucleus pulposus at all vertebral levels in all movements, in the osteoporosis group than in the normal group. On the annulus fibrosus, the von Mises stress increased at the level of L3-L4, L4-L5, and L5-S in the flexion-extension group and at L4-L5 and L5-S levels in the lateral bending group. The values of two motions, flexion-extension and lateral bending, increased in the L4 and L5 cortical bones. In axial rotation, the von Mises stress increased at the level of L5 of cortical bone. Additionally, the von Mises stress increased in the lower endplate of L5-S and L4-L5 in all movements, especially lateral bending. Even in the group with no increase, there was a part that received increased von Mises stress locally for each element in the three-dimensional reconstructed view of the pressure distribution in color. The von Mises stress on the lumbar region in the three loading conditions, was greater in most components of osteoporotic vertebrae than in normal vertebrae and the value was highest in the nucleus pulposus. Considering the increase in the measured von Mises stress and the local increase in the pressure distribution, we believe that these results can contribute to explaining discogenic pain and degeneration.
Topics: Biomechanical Phenomena; Finite Element Analysis; Humans; Lumbar Vertebrae; Lumbosacral Region; Osteoporosis; Range of Motion, Articular; Spinal Fusion
PubMed: 35768481
DOI: 10.1038/s41598-022-15241-3 -
PloS One 2022Interspinous spacer devices used in interspinous fixation surgery remove soft tissues in the lumbar spine, such as ligaments and muscles and may cause degenerative...
Interspinous spacer devices used in interspinous fixation surgery remove soft tissues in the lumbar spine, such as ligaments and muscles and may cause degenerative diseases in adjacent segments its stiffness is higher than that of the lumbar spine. Therefore, this study aimed to structurally and kinematically optimize a lumbar interspinous fixation device (LIFD) using a full lumbar finite element model that allows for minimally invasive surgery, after which the normal behavior of the lumbar spine is not affected. The proposed healthy and degenerative lumbar spine models reflect the physiological characteristics of the lumbar spine in the human body. The optimum number of spring turns and spring wire diameter in the LIFD were selected as 3 mm and 2 turns, respectively-from a dynamic range of motion (ROM) perspective rather than a structural maximum stress perspective-by applying a 7.5 N∙m extension moment and 500 N follower load to the LIFD-inserted lumbar spine model. As the spring wire diameter in the LIFD increased, the maximum stress generated in the LIFD increased, and the ROM decreased. Further, as the number of spring turns decreased, both the maximum stress and ROM of the LIFD increased. When the optimized LIFD was inserted into a degenerative lumbar spine model with a degenerative disc, the facet joint force of the L3-L4 lumbar segment was reduced by 56%-98% in extension, lateral bending, and axial rotation. These results suggest that the optimized device can strengthen the stability of the lumbar spine that has undergone interspinous fixation surgery and reduce the risk of degenerative diseases at the adjacent lumbar segments.
Topics: Biomechanical Phenomena; Finite Element Analysis; Humans; Intervertebral Disc Degeneration; Lumbar Vertebrae; Range of Motion, Articular; Spinal Fusion
PubMed: 35390024
DOI: 10.1371/journal.pone.0265926 -
The Journal of Bone and Joint Surgery.... Mar 2024➤ Sagittal alignment of the spine has gained attention in the field of spinal deformity surgery for decades. However, emerging data support the importance of restoring...
➤ Sagittal alignment of the spine has gained attention in the field of spinal deformity surgery for decades. However, emerging data support the importance of restoring segmental lumbar lordosis and lumbar spinal shape according to the pelvic morphology when surgically addressing degenerative lumbar pathologies such as degenerative disc disease and spondylolisthesis.➤ The distribution of caudal lordosis (L4-S1) and cranial lordosis (L1-L4) as a percentage of global lordosis varies by pelvic incidence (PI), with cephalad lordosis increasing its contribution to total lordosis as PI increases.➤ Spinal fusion may lead to iatrogenic deformity if performed without attention to lordosis magnitude and location in the lumbar spine.➤ A solid foundation of knowledge with regard to optimal spinal sagittal alignment is beneficial when performing lumbar spinal surgery, and thoughtful planning and execution of lumbar fusions with a focus on alignment may improve patient outcomes.
Topics: Humans; Lordosis; Radiography; Lumbar Vertebrae; Spondylolisthesis; Lumbosacral Region; Spinal Fusion; Retrospective Studies
PubMed: 38271548
DOI: 10.2106/JBJS.23.00672 -
Annals of Biomedical Engineering Jul 2022Prolonged microgravity results in muscle atrophy, especially among the anti-gravity spinal muscles. How individual paravertebral muscle groups change in size and...
Prolonged microgravity results in muscle atrophy, especially among the anti-gravity spinal muscles. How individual paravertebral muscle groups change in size and composition with spaceflight needs further exploration. This study investigates lumbar spine musculature changes among six crewmembers on long-duration space missions using non-invasive measurement of muscle changes with magnetic resonance imaging (MRI). Pre- and post-flight lumbar images were analyzed for changes in cross-sectional area, volume, and fat infiltration of the psoas (PS), quadratus lumborum (QL), and paraspinal [erector spinae and multifidus (ES + MF)] muscles using mixed models. Crewmembers used onboard exercise equipment, including a cycle ergometer (CEVIS), treadmill (T2/COLBERT), and the advanced resistive exercise device (ARED). Correlations were used to assess muscle changes related to exercise modality. There was substantial variability in muscle changes across crewmembers but collectively a significant decrease in paraspinal area (- 9.0 ± 4.8%, p = 0.04) and a significant increase in QL fat infiltration (7.3 ± 4.1%, p = 0.05). More CEVIS time may have protected against PS volume loss (p = 0.05) and PS fat infiltration (p < 0.01), and more ARED usage may have protected against ES + MF volume loss (p = 0.05). Crewmembers using modern onboard exercise equipment may be less susceptible to muscle changes. However, variability between crewmembers and muscle size and quality losses suggest additional research is needed to ensure in-flight countermeasures preserve muscle health.
Topics: Lumbar Vertebrae; Lumbosacral Region; Magnetic Resonance Imaging; Paraspinal Muscles; Space Flight
PubMed: 35459964
DOI: 10.1007/s10439-022-02968-3 -
Journal of Biomechanical Engineering Oct 2018Current implant materials and designs used in spinal fusion show high rates of subsidence. There is currently a need for a method to predict the mechanical properties of...
Current implant materials and designs used in spinal fusion show high rates of subsidence. There is currently a need for a method to predict the mechanical properties of the endplate using clinically available tools. The purpose of this study was to develop a predictive model of the mechanical properties of the vertebral endplate at a scale relevant to the evaluation of current medical implant designs and materials. Twenty vertebrae (10 L1 and 10 L2) from 10 cadavers were studied using dual-energy X-ray absorptiometry to define bone status (normal, osteopenic, or osteoporotic) and computed tomography (CT) to study endplate thickness (μm), density (mg/mm3), and mineral density of underlying trabecular bone (mg/mm3) at discrete sites. Apparent Oliver-Pharr modulus, stiffness, maximum tolerable pressure (MTP), and Brinell hardness were measured at each site using a 3 mm spherical indenter. Predictive models were built for each measured property using various measures obtained from CT and demographic data. Stiffness showed a strong correlation between the predictive model and experimental values (r = 0.85), a polynomial model for Brinell hardness had a stronger predictive ability compared to the linear model (r = 0.82), and the modulus model showed weak predictive ability (r = 0.44), likely due the low indentation depth and the inability to image the endplate at that depth (≈0.15 mm). Osteoporosis and osteopenia were found to be the largest confounders of the measured properties, decreasing them by approximately 50%. It was confirmed that vertebral endplate mechanical properties could be predicted using CT and demographic indices.
Topics: Adult; Aged; Biomechanical Phenomena; Female; Hardness; Humans; Lumbar Vertebrae; Male; Materials Testing; Mechanical Phenomena; Middle Aged; Tomography, X-Ray Computed
PubMed: 30029240
DOI: 10.1115/1.4040252 -
Arthritis and Rheumatism Dec 2012
Topics: Adult; Congenital Abnormalities; Diagnosis, Differential; Discitis; Female; Humans; Low Back Pain; Lumbar Vertebrae; Spinal Fractures; Tomography, X-Ray Computed
PubMed: 22833300
DOI: 10.1002/art.34630 -
Canadian Journal of Surgery. Journal... Oct 2001During adolescence the spine undergoes rapid growth and changes in anatomy and biomechanical properties. Fractures of the adolescent spine are relatively uncommon but... (Review)
Review
During adolescence the spine undergoes rapid growth and changes in anatomy and biomechanical properties. Fractures of the adolescent spine are relatively uncommon but may give rise to serious problems. This review describes thoracolumbar fractures in adolescents with respect to epidemiology, anatomy, mechanisms of injury, clinical and radiologic assessment, and nonoperative and operative treatment. The treatment of these injuries follows many of the same principles as spinal fractures in adults but nonoperative treatment is used more frequently because there is less spinal instability and better tolerance of bed rest and spinal immobilization in this young population.
Topics: Adolescent; Biomechanical Phenomena; Humans; Lumbar Vertebrae; Radiography; Spinal Fractures; Thoracic Vertebrae
PubMed: 11603746
DOI: No ID Found -
Journal of Orthopaedic Surgery and... Jan 2023Anterior lumbar interbody fusion (ALIF) and oblique lumbar interbody fusion (OLIF) have shown a great surgical potential, while it has always been controversial which...
BACKGROUND AND OBJECTIVE
Anterior lumbar interbody fusion (ALIF) and oblique lumbar interbody fusion (OLIF) have shown a great surgical potential, while it has always been controversial which surgical approach and which type of fixation system should be selected. This study investigated the biomechanical response of ALIF and OLIF with various supplementary fixation systems using the finite element method.
MATERIALS AND METHODS
Lumbar L4-L5 ALIF and OLIF models stabilized by different supplementary fixation systems (stand-alone cage, integrated stand-alone cage, anterior plate, and bilateral pedicle screw) were developed to assess the segmental range of motion (ROM), endplate stress (EPS), and screw-bone interface stress (SBIS).
EXPERIMENTAL RESULTS
ALIF showed lower ROM and EPS than OLIF in all motion planes and less SBIS in the most of motion planes compared with OLIF when the anterior plate or pedicle screw was used. ALIF induced higher ROM, while lower EPS and SBIS than OLIF in the majority of motion planes when integrated stand-alone cage was utilized. Using a stand-alone cage in ALIF and OLIF led to cage migration. Integrated stand-alone cage prevented the cage migration, whereas caused significantly larger ROM, EPS, and SBIS than other fixation systems except for the rotation plane. In the most of motion planes, the pedicle screw had the lowest ROM, EPS, and SBIS. The anterior plate induced a slightly larger ROM, EPS, and SBIS than the pedicle screw, while the differences were not significant.
CONCLUSION
ALIF exhibited a better performance in postoperative segmental stability, endplate stress, and screw-bone interface stress than OLIF when the anterior plate or the pedicle screw was used. The pedicle screw could provide the greatest postoperative segmental stability, less cage subsidence incidence, and lower risk of fixation system loosening in ALIF and OLIF. The anterior plate could also contribute to the stability required and fewer complications, while not as effectively as the pedicle screw. Extreme caution should be regarded when the stand-alone cage is used due to the risk of cage migration. The integrated stand-alone cage may be an alternative method; however, further optimization is needed to reduce complications and improve postoperative segmental stability.
Topics: Finite Element Analysis; Spinal Fusion; Lumbar Vertebrae; Biomechanical Phenomena; Pedicle Screws; Range of Motion, Articular
PubMed: 36593501
DOI: 10.1186/s13018-022-03480-z -
Radiologia 2013Given the prevalence of low back pain, surgical interventions on the lumbar spine are becoming more common. Among the many surgical procedures available for these... (Review)
Review
Given the prevalence of low back pain, surgical interventions on the lumbar spine are becoming more common. Among the many surgical procedures available for these interventions, the most common are laminectomy and discectomy. In 10 to 40% of patients who undergo surgical interventions on the lumbar spine, low back pain is not completely alleviated or it recurs, and these cases fall into the category of « failed back surgery syndrome ». This syndrome can have many different causes and multiple factors are often involved. It is important not to confuse the normal postoperative findings with those specific to failed back surgery syndrome. Deciding which imaging technique to use will depend on the type of surgical intervention, whether metallic orthopedic material was used, and the clinical suspicion. It is essential to know the advantages and limitations of the available imaging techniques to ensure the optimal evaluation of these patients, especially after interventions carried out with instrumentation to minimize the artifacts due to these materials.
Topics: Adult; Aged; Female; Humans; Low Back Pain; Lumbar Vertebrae; Magnetic Resonance Imaging; Male; Middle Aged; Postoperative Care; Tomography, X-Ray Computed
PubMed: 22520556
DOI: 10.1016/j.rx.2011.12.004 -
Acta Neurochirurgica Jun 2023This study aimed to guide the more efficient management of type 4 and 5 thoracolumbar or lumbar osteoporotic fractures (OF) in patients aged 80 years and older with an...
Perioperative morbidity and mortality in octogenarians sustaining traumatic osteoporotic type 4 and 5 thoracolumbar and lumbar fractures: a retrospective study with 3 years follow-up.
PURPOSE
This study aimed to guide the more efficient management of type 4 and 5 thoracolumbar or lumbar osteoporotic fractures (OF) in patients aged 80 years and older with an acute onset of neurological decline. This aim was achieved by assessing the clinical course and morbidity and mortality rates and identifying potential risk factors for patient mortality METHODS: Electronic medical records were retrieved from a single institution pertaining to the period between September 2005 and December 2020. Data on patient demographics, neurological conditions, surgical characteristics, complications, hospital course, and 90-day mortality were also collected.
RESULTS
Over a 16-year period, 35 patients aged ≥80 years diagnosed with thoracolumbar and lumbar OF were enrolled in the study. The mean Charlson comorbidity index (CCI) was >6, indicating a poor baseline reserve (9.4 ± 1.9), while cardiovascular diseases were the most prevalent among comorbidities. The mean surgical duration was 231.6 ± 89.3 min, with a mean blood loss of 694.4± 200.3 mL. The in-hospital was 8.6% and 90-day mortality rates at 11.4%. Two patients underwent revision surgery for deep wound infection. Intraoperative and postoperative radiography and computed tomography (CT) imaging revealed correct screw placement. Proper alignment of the thoracolumbar spine was achieved in all the patients. Unique risk factors for mortality included the presence of comorbidities and the occurrence of postoperative complications.
CONCLUSIONS
Emergent instrumentation in patients with acute onset of neurological decline and potentially unstable spines due to thoracolumbar and lumbar OF improved functional outcomes at discharge. Age should not be a determinant of whether to perform surgery.
Topics: Aged, 80 and over; Humans; Retrospective Studies; Follow-Up Studies; Octogenarians; Lumbar Vertebrae; Thoracic Vertebrae; Spinal Fractures; Osteoporotic Fractures; Morbidity
PubMed: 37052705
DOI: 10.1007/s00701-023-05564-z