Influence of coronal-morphology of endplate and intervertebral space to cage subsidence and fusion following oblique lumbar interbody fusion.

BACKGROUND: Endplate morphology is considered to be one of the influencing factors of cage subsidence after lumbar interbody fusion (LIF). Previous radiographic evaluations on the endplate mostly used sagittal X-ray or MRI. However, there are few studies on the CT evaluation of the endplate and intervertebral space (IVS), especially the evaluation of coronal morphology and its influence on subsidence and fusion after LIF. We aimed to measure and classify the shapes of the endplate and IVS using coronal CT imaging and evaluate the radiographic and clinical outcomes of different shapes of the endplate/IVS following oblique lateral lumbar interbody fusion (OLIF). METHODS: A total of 137 patients (average age 59.1 years, including 75 males and 62 females) who underwent L4-5 OLIF combined with anterolateral fixation from June 2018 to June 2020 were included. The endplate concavity depth (ECD) was measured on the preoperative coronal CT image. According to ECD, the endplate was classified as flat (< 2 mm), shallow (2-4 mm), or deep (> 4 mm). The L4-5 IVS was further classified according to endplate type. The disc height (DH), DH changes, subsidence rate, fusion rate, and Oswestry Disability Index (ODI) in different endplate/IVS shapes were evaluated during 1-year follow up. RESULTS: The ECD of L4 inferior endplate (IEP) was significantly deeper than that of L5 superior endplate (SEP) (4.2 ± 1.1 vs 1.6 ± 0.8, P < 0.01). Four types of L4-5 IVS were identified: shallow-shallow (16, 11.7%), shallow-flat (45, 32.9%), deep-shallow (32, 23.4%), and deep-flat (44, 32.1%). A total of 45 (32.9%) cases of cage subsidence were observed. Only one (6.3%) subsidence event occurred in the shallow-shallow group, which was significantly lower than in the other three groups (19 shallow-flat, 6 deep-shallow, and 19 deep-flat) (P < 0.05). Meanwhile, the shallow-shallow group had the highest fusion rate (15, 93.8%) and the highest rate of reach minimal clinically important difference (MCID) ODI among the four types. For a single endplate, the shape of L4 IEP is the main influencing factor of the final interbody fusion rate, and the shallow shape L4 IEP facilitates fusion ( OR = 2.85, p = 0.03). On the other hand, the flat shape L5 SEP was the main risk factor to cage subsidence (OR = 4.36, p < 0.01). CONCLUSION: The L4-5 IVS is asymmetrical on coronal CT view and tends to be fornix-above and flat-down. The shallow-shallow IVS has the lowest subsidence rate and best fusion result, which is possibly because it has a relatively good degree in matching either the upper or lower interface of the cage and endplates. These findings provide a basis for the further improvements in the design of OLIF cages.

Effects of a soil collembolan on the growth and metal uptake of a hyperaccumulator: Modification of root morphology and the expression of plant defense genes.

Soil collembolans live in close proximity to plant roots and may have a role in the phytoextraction of potentially toxic metals from contaminated soils but the underlying mechanisms remain poorly investigated. We hypothesize that soil collembolans may change the root morphology of hyperaccumulators by regulating plant physiological characteristics. Here, a pot experiment was conducted in which a cadmium (Cd) and zinc (Zn) hyperaccumulator (Sedum plumbizincicola) was grown with or without a collembolan (Folsomia candida), and plant transcriptome and hormones as well as the root characteristics of S. plumbizincicola were analyzed. F. candida promoted the growth and Cd/Zn uptake of S. plumbizincicola, the root and shoot biomass increasing by 53.3 and 34.4%, and the uptake of Cd and Zn in roots increased by 83.2 and 65.4%, respectively. Plant root morphology, total root length, root tip number and lateral root number increased significantly by 40.7, 37.2 and 33.8%, respectively, with the addition of F. candida. Transcriptome analysis reveals that the expression levels of defense-related genes in S. plumbizincicola were significantly up-regulated. In addition, the defensive plant hormones, i.e. salicylic acid in the roots, increased significantly by 338%. These results suggest that the plant in defense of the action of F. candida regulated the expression of the corresponding genes and increased the defensive plant hormones, thus modifying root morphology and plant performance. Overall, this study highlights the importance of the regulation by collembolans of plant growth and metal uptake by interaction with hyperaccumulator roots.

Development and validation of equations for conversion from DAS28ESR and DAS28CRP to the SDAI in patients with rheumatoid arthritis.

INTRODUCTION: Disease Activity Score-28 (DAS28) with erythrocyte sedimentation rate (DAS28ESR), DAS28 with C-reactive protein (DAS28CRP), and simplified disease activity index (SDAI) are widely used to assess disease activity as low, moderate, or high or in remission in patients with rheumatoid arthritis (RA). However, these indicators can generate inconsistent results, influencing treatment decisions and limiting comparisons across studies. We aimed to establish equations for conversion from DAS28ESR and DAS28CRP to SDAI. METHODS: We conducted a retrospective study, including 933 outpatients who were simultaneously assessed using DAS28ESR, DAS28CRP, and SDAI. The patients were divided into a training set (70%) and a validation set (30%). We developed equations to convert DAS28ESR and DAS28CRP values into SDAI values by bisquare-weighted robust regression to obtain SDAI-DAS28ESR and SDAI-DAS28CRP. In addition to using kappa values to assess consistency, differences in disease activity classification between SDAI-DAS28ESR and SDAI-DAS28CRP were examined by the Stuart-Maxwell test and the Bowker test. RESULTS: Two quadratic equations were developed as follows: SDAI-DAS28ESR = 1.168 × (DAS28ESR)^2 - 2.432 × (DAS28ESR) + 2.649 and SDAI-DAS28CRP = 1.2 × (DAS28CRP)^2 - 0.3522 × (DAS28CRP) - 0.6014. After applying the equations, the Stuart-Maxwell test and the Bowker test were no longer significant between SDAI-DAS28ESR and SDAI or between SDAI-DAS28CRP and SDAI. The kappa values increased from 0.57 to 0.73 between SDAI-DAS28ESR and SDAI and 0.76 to 0.86 between SDAI-DAS28CRP and SDAI. CONCLUSION: SDAI-DAS28ESR and SDAI-DAS28CRP are interchangeable with the SDAI on the group level, which will facilitate comparisons among studies. In addition, the equations improved consistency between indicators. Key Points • There is disagreement in assessing disease activity in patients with rheumatoid arthritis between Disease Activity Score-28 (DAS28) with erythrocyte sedimentation rate (DAS28ESR), DAS28 with C-reactive protein (DAS28CRP), and simplified disease activity index (SDAI). • We developed and validated two quadratic equations to convert DAS28ESR and DAS28CRP into SDAI. We found there was no longer significant difference in disease activity between indicators after applying the equations. • This work may allow comparisons across studies which use different indicators.