High-Demand Spinal Deformity With Multi-Rod Constructs and Porous Fusion/Fixation Implants: A Finite Element Study

STUDY DESIGN

Basic science (finite element analysis).

OBJECTIVES

Pedicle subtraction osteotomy (PSO) at L5 is an effective treatment for sagittal imbalance, especially in select cases of patients showing kyphosis with the apex at L4-L5 but has been scarcely investigated. The aim of this study was to simulate various "high-demand" instrumentation approaches, including varying numbers of rods and sacropelvic implants, for the stabilization of a PSO at L5.

METHODS

A finite element model of T10-pelvis was modified to simulate posterior fixation with pedicle screws and rods from T10 to S1, alone or in combination with an L5 PSO. Five additional configurations were then created by employing rods and novel porous fusion/fixation implants across the sacroiliac joints, in varying numbers. All models were loaded using pure moments of 7.5 Nm in flexion-extension, lateral bending, and axial rotation.

RESULTS

The osteotomy resulted in a general increase in motion and stresses in posterior rods and S1 pedicle screws. When the number of rods was varied, three- and four-rod configurations were effective in limiting the maximal rod stresses; values approached those of posterior fixation with no osteotomy. Maximum stresses in the accessory rods were similar to or less than those observed in the primary rods. Multiple sacropelvic implants were effective in reducing range of motion, particularly of the SIJ.

CONCLUSIONS

Multi-rod constructs and sacropelvic fixation generally reduced maximal implant stresses and motion in comparison with standard posterior fixation, suggesting a reduced risk of rod breakage and increased joint stability, respectively, when a high-demand construct is utilized for the correction of sagittal imbalance.

Epidemiological differences between the sexes in adolescent patients with lumbar spondylolysis: a single-institution experience in Japan

BACKGROUND

Lumbar spondylolysis, a common identifiable cause of low back pain in young athletes, reportedly has a higher incidence rate in males. However, the reason for its higher incidence in males is not clear. This study aimed to investigate the epidemiological differences between the sexes in adolescent patients with lumbar spondylolysis.

METHODS

A retrospective study was conducted in 197 males and 64 females diagnosed with lumbar spondylolysis. These patients visited our institution from April 2014 to March 2020 with their main complaint being low back pain, and they were followed-up until the end of their treatment. We investigated associations between lumbar spondylosis, their background factors, and characteristics of the lesions and analyzed their treatment results.

RESULTS

Males had a higher prevalence of spina bifida occulta (SBO) (p = 0.0026), more lesions with bone marrow edema (p = 0.0097), and more lesions in the L5 vertebrae (p = 0.021) than females. The popular sports disciplines were baseball, soccer, and track and field in males, and volleyball, basketball, softball in females. The dropout rate, age at diagnosis, bone union rate, and treatment period did not differ between the sexes.

CONCLUSION

Lumbar spondylolysis was more common in males than in females. SBO, bone marrow edema, and L5 lesions were more frequent in males, and sports discipline varied between the sexes.

The Association between Electronegative Low-Density Lipoprotein Cholesterol L5 and Cognitive Functions in Patients with Mild Cognitive Impairment

L5, the most electronegative subfraction of low-density lipoprotein cholesterol (LDL-C), may play a role in the pathogenesis of cerebrovascular dysfunction and neurodegeneration. We hypothesized that serum L5 is associated with cognitive impairment and investigated the association between serum L5 levels and cognitive performance in patients with mild cognitive impairment (MCI). This cross-sectional study conducted in Taiwan included 22 patients with MCI and 40 older people with normal cognition (healthy controls). All participants were assessed with the Cognitive Abilities Screening Instrument (CASI) and a CASI-estimated Mini-Mental State Examination (MMSE-CE). We compared the serum total cholesterol (TC), LDL-C, and L5 levels between the MCI and control groups and examined the association between lipid profiles and cognitive performance in these groups. The serum L5 concentration and total CASI scores were significantly negatively correlated in the MCI group. Serum L5% was negatively correlated with MMSE-CE and total CASI scores, particularly in the orientation and language subdomains. No significant correlation between the serum L5 level and cognitive performance was noted in the control group. Conclusions: Serum L5, instead of TC or total LDL-C, could be associated with cognitive impairment through a disease stage-dependent mode that occurs during neurodegeneration.

The potential pathophysiological role of altered lipid metabolism and electronegative low-density lipoprotein (LDL) in non-alcoholic fatty liver disease and cardiovascular diseases

Non-alcoholic fatty liver disease (NAFLD) is an umbrella term for a range of conditions caused by a build-up of fat in the liver. It is usually seen in people who are overweight or obese. Increasingly common around the world, this disease is the most common chronic liver disease in the United States, affecting about a quarter of the population. Recently, the designation of NAFLD as 'metabolic dysfunction-associated fatty liver disease' (MAFLD) has been a subject of current debate. In this context, 'insulin resistance' is the underlying common and basic pathophysiological mechanism of metabolic dysfunction due to its association with obesity, type 2 diabetes mellitus (T2DM), metabolic syndrome, dyslipidemia and NAFLD. All these pathological conditions are among the metabolic risk factors for cardiovascular diseases, too. Also, due to the bidirectional causality between NAFLD and cardiovascular diseases, a liver-heart axis is suggested. Therefore, various factors such as insulin resistance as well as systemic inflammation, cytokines, oxidative stress, adipokines, hepatokines, genes and intestinal microbiota have been identified as possible pathogenic factors that play a role in the explanation of the complex NAFLD and cardiovascular risk relationship. Recent data and cumulative evidence show that electronegative low-density lipoprotein [LDL (-)/L5] cholesterol is a promising biomarker for complex organ interactions and diseases associated with liver-heart axis. In this mini review, we focus not only on recent data on NAFLD mechanisms, but also on the potential of the lipid mediator LDL (-)/L5 as a diagnostic and therapeutic target for liver-heart line diseases.

Autoimmune Rheumatic Diseases: An Update on the Role of Atherogenic Electronegative LDL and Potential Therapeutic Strategies

Atherosclerosis has been linked with an increased risk of atherosclerotic cardiovascular disease (ASCVD). Autoimmune rheumatic diseases (AIRDs) are associated with accelerated atherosclerosis and ASCVD. However, the mechanisms underlying the high ASCVD burden in patients with AIRDs cannot be explained only by conventional risk factors despite disease-specific factors and chronic inflammation. Nevertheless, the normal levels of plasma low-density lipoprotein (LDL) cholesterol observed in most patients with AIRDs do not exclude the possibility of increased LDL atherogenicity. By using anion-exchange chromatography, human LDL can be divided into five increasingly electronegative subfractions, L1 to L5, or into electropositive and electronegative counterparts, LDL (+) and LDL (-). Electronegative L5 and LDL (-) have similar chemical compositions and can induce adverse inflammatory reactions in vascular cells. Notably, the percentage of L5 or LDL (-) in total LDL is increased in normolipidemic patients with AIRDs. Electronegative L5 and LDL (-) are not recognized by the normal LDL receptor but instead signal through the lectin-like oxidized LDL receptor 1 (LOX-1) to activate inflammasomes involving interleukin 1β (IL-1β). Here, we describe the detailed mechanisms of AIRD-related ASCVD mediated by L5 or LDL (-) and discuss the potential targeting of LOX-1 or IL-1β signaling as new therapeutic modalities for these diseases.

Association of Electronegative LDL with Macrophage Foam Cell Formation and CD11c Expression in Rheumatoid Arthritis Patients

L5, the most negatively charged subfraction of low-density lipoprotein (LDL), is implicated in atherogenesis, but the pathogenic association is relatively unexplored in patients with rheumatoid arthritis (RA). We examined the role of L5 LDL in macrophage foam cell formation and the association of L5 with CD11c expression in THP-1 cells and RA patients. Using quantitative real-time PCR, we determined mRNA expression levels of ITGAX, the gene for CD11c, a marker associated with vascular plaque formation and M1 macrophages in atherogenesis, in 93 RA patients. We also examined CD11c expression on THP-1 cells treated with L5 by flow cytometry analysis and the plasma levels of inflammatory mediators using a magnetic bead array. We found a dose-dependent upregulation of foam cell formation of macrophages after L5 treatment (mean ± SEM, 12.05 ± 2.35% in L5 (10 µg/mL); 50.13 ± 3.9% in L5 (25 µg/mL); 90.69 ± 1.82% in L5 (50 µg/mL), p < 0.01). Significantly higher levels of CD11c expression were observed in 30 patients with a high percentage of L5 in LDL (L5%) (0.0752 ± 0.0139-fold) compared to 63 patients with normal L5% (0.0446 ± 0.0054-fold, p < 0.05). CD11c expression levels were increased in the L5-treated group (30.00 ± 3.13% in L5 (10 µg/mL); 41.46 ± 2.77% in L5 (50 µg/mL), p < 0.05) and were positively correlated with plasma levels of interleukin (IL)-6 and IL-8. L5 augmented the expression of IL-6, IL-8, and tumor necrosis factor-α (TNF-α) on monocytes and macrophages. Our findings suggest that L5 may promote atherogenesis by augmenting macrophage foam cell formation, upregulating CD11c expression, and enhancing the expression levels of atherosclerosis-related mediators.

Combined LDL and VLDL Electronegativity Correlates with Coronary Heart Disease Risk in Asymptomatic Individuals

The most electronegative constituents of human plasma LDL (i.e., L5) and VLDL (i.e., V5) are highly atherogenic. We determined whether the combined electronegativity of L5 and V5 (i.e., L5 + V5) plays a role in coronary heart disease (CHD). In 33 asymptomatic individuals (ages 32–64), 10-year hard CHD risk correlated with age (r = 0.42, p = 0.01). However, in age-adjusted analyses, 10-year hard CHD risk correlated with L5 + V5 plasma concentration (r = 0.43, p = 0.01) but not age (p = 0.74). L5 + V5 plasma concentration was significantly greater in the group with high CHD risk (39.4 ± 22.0 mg/dL; n = 17) than in the group with low CHD risk (16.9 ± 14.8 mg/dL; n = 16; p = 0.01). In cultured human aortic endothelial cells, L5 + V5 treatment induced significantly more senescence-associated–β-Gal activity than did equal concentrations of L1 + V1 (n = 4, p < 0.001). To evaluate the in vivo relevance of these findings, we fed ApoE^−/− and wild-type mice with a high-fat diet and found that plasma LDL, VLDL, and LDL + VLDL from ApoE^−/− mice exhibited significantly greater electrophoretic mobility than did wild-type counterparts (n = 6, p < 0.01). The increased electronegativity of LDL and VLDL in ApoE^−/− mice was accompanied by increased aortic lipid accumulation and cellular senescence (n = 6, p < 0.05). Clinical trials are warranted to test the predictive value of L5 + V5 concentration in patients with CHD.

Circadian ontogeny through the lens of nonparametric variables of actigraphy

Studies focusing on human rhythmicity show that human circadian rhythm suffers constant changes across lifespan. Changes in rest-activity patterns can be studied through nonparametric variables of actigraphy: L5 (an individual's least active 5 h), M10 (an individual's most active 10 h) and RA (relative amplitude of the rest-activity rhythm). The variable RA is the normalized difference between L5 and M10 - the higher the RA, the greater the difference between these two variables. This study used the data bank of the Human Chronobiology Laboratory of Federal University of Paraná (Brazil). It analyzed actimetric data of 93 children between 4 and 11 years of age in their naturalistic context in order to describe the development of nonparametric variables. Correlation between age and L5 was significantly negative (rho = - 0.29, p = 0.004), while correlation between age and RA was significantly positive (rho = 0.31, p = 0.003). The variables M10, sL5 (start of L5) and sM10 (start of M10) did not show significant correlation to age. Furthermore, there were no statistical differences between genders. The population of this study, healthy children, has been poorly assessed by similar literature. Through our results, we have demonstrated that, as children age, L5 significantly decreases, which reflects a smaller fragmentation of circadian rhythm. As an expected consequence, RA significantly increases. In other words, these nonparametric variables of actimetry successfully demonstrate that children tend to reduce nocturnal activity as they age, a phenomenon that reflects the ongoing consolidation of circadian rhythm.

Electronegative LDL: An Active Player in Atherogenesis or a By- Product of Atherosclerosis?

Low-density lipoproteins (LDLs) are the major plasma carriers of cholesterol. However, LDL particles must undergo various molecular modifications to promote the development of atherosclerotic lesions. Modified LDL can be generated by different mechanisms, but as a common trait, show an increased electronegative charge of the LDL particle. A subfraction of LDL with increased electronegative charge (LDL(-)), which can be isolated from blood, exhibits several pro-atherogenic characteristics. LDL(-) is heterogeneous, due to its multiple origins but is strongly related to the development of atherosclerosis. Nevertheless, the implication of LDL(-) in a broad array of pathologic conditions is complex and in some cases anti-atherogenic LDL(-) properties have been reported. In fact, several molecular modifications generating LDL(-) have been widely studied, but it remains unknown as to whether these different mechanisms are specific or common to different pathological disorders. In this review, we attempt to address these issues examining the most recent findings on the biology of LDL(-) and discussing the relationship between this LDL subfraction and the development of different diseases with increased cardiovascular risk. Finally, the review highlights the importance of minor apolipoproteins associated with LDL(-) which would play a crucial role in the different properties displayed by these modified LDL particles.

Association between Negatively Charged Low-Density Lipoprotein L5 and Subclinical Atherosclerosis in Rheumatoid Arthritis Patients

L5, the most negatively charged subfraction of low-density lipoprotein (LDL), is implicated in atherogenesis. We examined the relationship between plasma L5 levels and the occurrence of subclinical atherosclerosis in patients with rheumatoid arthritis (RA). Using anion-exchange purification with fast-protein liquid chromatography, we determined the proportion of plasma L5 of LDL (L5%) in 64 RA patients and 12 healthy controls (HC). Plasma L5% and L5 levels were significantly higher in RA patients (median, 1.4% and 1.92 mg/dL) compared with HC (0.9%, p < 0.005; and 1.27 mg/dL, p < 0.05) and further increased in patients with subclinical atherosclerosis (2.0% and 2.88 mg/dL). L5% and L5 levels decreased in patients after 6-months of therapy (p < 0.01). Subclinical atherosclerosis was indicated by plaque and intima-media thickness determined by carotid ultrasonography. Using multivariate analysis, L5% and L5 levels are revealed as the predictors of subclinical atherosclerosis (odds ratio, 4.94 and 1.01; both p < 0.05). Receiver operating characteristic curves showed that cut-off values of L5% ≥ 1.45% and L5 levels ≥ 2.58 mg/dL could predict subclinical atherosclerosis in patients (both p < 0.001). Immunoblotting showed that the expression levels of lectin-like oxidized LDL receptor-1 (LOX-1) was increased in RA patients. Together, our findings suggest that plasma L5% and L5 levels may be predictors of cardiovascular risk in RA patients.

Feasibility of total en-bloc spondylectomy on L5 by a posterior-only approach: An autopsy study

Purpose

To obtain a better understanding of the structures around L5 vertebra and provide some anatomical evidence of the feasibility of total en-bloc spondylectomy (TES) on L5 in a posterior-only approach.

Methods

12 simulated TESs on L5 by a posterior-only approach were conducted on human cadavers. The distance between the traction point of L4 nerve root and the dural sac (Da), the anterior-posterior diameter of the vertebral body,(Va), the distance between the start point of L4 nerve root and the traction point of L5 nerve root (Dh) and the height of the vertebral body (Vh) were measured. Paired t-test and liner regression were performed to determine the difference and correlation between Da and Va, and between Dh and Vh. The risk of nerve roots or blood vessels damages, and the obstruction caused by iliac wings were evaluated.

Results

Liner correlations were found between Da and Va, and between Dh and Vh. The regression equations were Da = 0.6673Va + 11.28 and Dh = 1.009Vh + 1.003. There are statistical significant differences between Dh and Vh, and between Da and Va in those whose Va < 34.96 mm. Nerve roots or blood vessels damages and the obstruction caused by iliac wing were able to be avoided.

Conclusions

If the patient has an anterior-posterior diameter of L5 vertebral body shorter than 34.96 mm, it is possible that the vertebral body can be taken out during TES in a posterior-only approach. Prevention of nerve roots or blood vessels damages, and the obstruction caused by iliac wings are difficulties of this procedure yet not insurmountable. TES on L5 by a posterior-only approach might a possible alternative in treating diseases like L5 vertebral body tumors.

Clinching the cause: A review of foot drop secondary to lumbar degenerative diseases

Foot drop is defined as weakness on dorsiflexion of the foot. The top two most common etiologies for foot drop include lumbar degenerative disease and common peroneal nerve injury. This review provides "updates" on understanding the lumbar etiologies of foot drop. Since the publication of "Preoperative motor strength and time to surgery are the most important predictors of improvement in foot drop due to degenerative lumbar disease" in the Journal of Neurological Sciences, three cohort studies have been published on spinal causes of foot drop. Classification, clinical features, diagnosis, and pathogenesis that may 'clinch' the cause of foot drop are discussed in the context of these recent publications.

Correlation between the sagittal spinopelvic alignment and degenerative lumbar spondylolisthesis: a retrospective study

Background

Pain and disability associated with degenerative lumbar spondylolisthesis (DLS) results in significant burden on both the patients’ quality of life and healthcare costs. Currently, there is controversy regarding the specificity of spinopelvic measures of sagittal plane alignment with respect to DLS. Moreover, the correlation among spinopelvic parameters of sagittal plane alignment remains to be clarified. Our aim in this study was to compare these measurements between patients with single-segment DLS at L5 and a control group with no history of DLS.

Methods

Our study group was formed of 132 patients who underwent full length lateral view radiographs of the spine in a relaxed standing posture. Among these, DLS at L5 was identified in 72 patients, forming the DLS group, with no radiographic evidence of lumbar spine disease in the remaining 60 patients, forming the control group. The patient and control groups were balanced with regard to age and sex distribution. The following spinopelvic parameters of sagittal plane alignment were measured: angle of incidence (PI) and tilt (PT) of the pelvis; sacral slope (SS); thoracic kyphosis (TK); lumbar lordosis (LL); and the spinal sagittal vertical axis (SVA). The Meyerding grade of L5 slippage was quantified for each patient in the DLS group.

Results

Measures of TK, PI, SS, and LL were significantly greater in the DLS than control group (P <  0.05), with no between-group difference in SVA and PT. In the DLS group, the grade of L5 slippage correlated with SS (r = 0.873, P <  0.0001), PI (r = 0.791, P <  0.0001) and LL (r = 0.790, P <  0.0001). Moreover, the measurement for SS correlated more strongly with the PI (r = 0.94, P <  0.01) than the LL (r = 0.69, P <  0.01).

Conclusion

Measurements of SS, PI, and LL were specifically associated with DLS, with measurements correlating positively with the grade of slippage.

Electronic supplementary material

The online version of this article (10.1186/s12891-018-2073-z) contains supplementary material, which is available to authorized users.

A misdiagnosed case of osteoid osteoma of L5

Clinically, it is difficult to differentiate osteoid osteoma, more than 50% of which occur in the fibia or tibia, from other diseases, i.e. spinal degenerative diseases, inflammatory and noninflammatory arthritis. In this case report, we presented an unusual case of lumbar osteoid osteoma in a 38-year-old male, who experienced low back pain and sciatica as initial symptoms. The patient was initially misdiagnosed as lumbar disc herniation for more than 10 years. With the usage of computed tomography (CT) and magnetic resonance imaging (MRI), the patient was finally diagnosed as osteoid osteoma in L5. To our knowledge, spinal osteoid osteoma with sciatica as initial symptoms has never been reported. Although lumbar vertebra osteoid osteoma is clinically uncommon, it should be taken into consideration especially when patients experience long duration of pain in lumbar.

The role of electronegative low-density lipoprotein in cardiovascular diseases and its therapeutic implications

Cardiovascular disease (CVD) is a health problem of great concern to both the public and medical authorities. Low-density lipoprotein (LDL) has been reported to play an important role in both the development and progression of CVD, but studies are underway to determine how LDL exerts its effects. In recent years, it has been found that LDL has several subfractions, each of which affects endothelial function differently; L5, the most electronegative fraction, has been shown to be unique in that it induces an atherogenic response. This review examines the current knowledge concerning the relationships between L5 and CVD and highlights the role of L5 in the pathophysiology of CVD, especially with regards to atherosclerosis.

Health information exchange, system size and information silos

There are many technology platforms that bring benefits only when users share data. In healthcare, this is a key policy issue, because of the potential cost savings and quality improvements from 'big data' in the form of sharing electronic patient data across medical providers. Indeed, one criterion used for federal subsidies for healthcare information technology is whether the software has the capability to share data. We find empirically that larger hospital systems are more likely to exchange electronic patient information internally, but are less likely to exchange patient information externally with other hospitals. This pattern is driven by instances where there may be a commercial cost to sharing data with other hospitals. Our results suggest that the common strategy of using 'marquee' large users to kick-start a platform technology has an important drawback of potentially creating information silos. This suggests that federal subsidies for health data technologies based on 'meaningful use' criteria, that are based simply on the capability to share data rather than actual sharing of data, may be misplaced.

The impact of the partnership long-term care insurance program on private coverage

We examine the impact of U.S. states' adoption of the partnership long-term care (LTC) insurance program on households' purchases of private coverage. Targeting middle-class households, this program increases the benefits of privately insuring via a higher asset threshold for Medicaid eligibility for LTC coverage. We find that the program generates few new purchases of LTC insurance, and that those it generates are almost entirely by wealthy individuals.

Kinesin-5: cross-bridging mechanism to targeted clinical therapy

Kinesin motor proteins comprise an ATPase superfamily that works hand in hand with microtubules in every eukaryote. The mitotic kinesins, by virtue of their potential therapeutic role in cancerous cells, have been a major focus of research for the past 28 years since the discovery of the canonical Kinesin-1 heavy chain. Perhaps the simplest player in mitotic spindle assembly, Kinesin-5 (also known as Kif11, Eg5, or kinesin spindle protein, KSP) is a plus-end-directed motor localized to interpolar spindle microtubules and to the spindle poles. Comprised of a homotetramer complex, its function primarily is to slide anti-parallel microtubules apart from one another. Based on multi-faceted analyses of this motor from numerous laboratories over the years, we have learned a great deal about the function of this motor at the atomic level for catalysis and as an integrated element of the cytoskeleton. These data have, in turn, informed the function of motile kinesins on the whole, as well as spearheaded integrative models of the mitotic apparatus in particular and regulation of the microtubule cytoskeleton in general. We review what is known about how this nanomotor works, its place inside the cytoskeleton of cells, and its small-molecule inhibitors that provide a toolbox for understanding motor function and for anticancer treatment in the clinic.