Spine Shape Research Articles

A new ornithopod from the Upper Cretaceous (Huincul Formation) of northwestern Patagonia, Argentina: Implications on elasmarian postcranial anatomy

The aim of the present contribution is to describe the first ornithischian species from the Huincul Formation (Cenomanian-Turonian, Upper Cretaceous) at the Pueblo Blanco Natural Reserve, Río Negro province, Argentina. The new species, named Chakisaurus nekul gen. et sp. nov., can be comfortably included among elasmarian ornithopods. The new species shows humeral anatomy that is congruent with smaller members of the clade (e.g. Anabisetia, Notohypsilophodon), and differs from larger taxa (e.g. Talenkauen, Mahuidacursor) which show humeral features probably related with graviportal habits, such as lack of shaft torsion and a distally located deltopectoral crest. This indicates that graviportal habits were probably acquired independently in elasmarians from other large-sized taxa, such as hadrosauroids. Caudal vertebrae of the new species also show a unique combination of characters shared with other elasmarians, which are absent in previously known ornithopods. These features indicate that some elasmarians had a protonic tail posture, which is unknown in other ornithischians and was previously considered unique to derived titanosaurian sauropods. The shape of transverse processes and neural spines of caudal vertebrae indicate that at least some elasmarians had improved cursorial habilities, that were convergently acquired by selected theropod clades.

Relationship between Treatment Choices according to the Modified Osteoporotic Fracture Score and Posttreatment Radiographic Outcomes.

Retrospective observational study. To evaluate the modified osteoporotic fracture (mOF) scores in three treatment groups and compare imaging findings in patients treated and not treated according to the mOF score-based treatment recommendation. The osteoporotic fracture (OF) score was established by the AO Spine to guide therapeutic decisions. To enhance its applicability, a mOF score was recently introduced. Consecutive patients diagnosed with OFs at Fujieda Heisei Memorial Hospital were divided into three groups: nonsurgical therapy, balloon kyphoplasty (BKP), and open surgery groups. The mOF score was calculated, and the levels of independence and posttreatment imaging data were compared between patients treated and not treated according to the mOF score-based treatment recommendation. In total, 118 patients were included (nonsurgical therapy, n=57; BKP, n=48; open surgery, n=13), of whom 100 (85%) received treatment consistent with the mOF score-based treatment recommendation. In the BKP and open surgery groups, the mOF scorebased treatment recommendations were consistent with the actual treatment in 93% of the patients. However, in the nonsurgical group, the mOF score-based treatment recommendation was not consistent with the actual treatment in 25% of the patients. In this group, patients not treated according to the mOF score had significantly shorter vertebral body height, greater local kyphosis, and smaller sacral slope after treatment than patients treated according to the mOF score-based treatment recommendation. In the BKP and open surgery groups, the mOF scores were consistent with actual clinical selection. In the nonsurgical therapy group, patients not treated according to the mOF score-based treatment recommendation exhibited severe vertebral body deformity and a less well-balanced spine shape after treatment. The mOF score may help in selecting suitable treatments for OFs.

A multiscale computational framework for the development of spines in molluscan shells.

From mathematical models of growth to computer simulations of pigmentation, the study of shell formation has given rise to an abundant number of models, working at various scales. Yet, attempts to combine those models have remained sparse, due to the challenge of combining categorically different approaches. In this paper, we propose a framework to streamline the process of combining the molecular and tissue scales of shell formation. We choose these levels as a proxy to link the genotype level, which is better described by molecular models, and the phenotype level, which is better described by tissue-level mechanics. We also show how to connect observations on shell populations to the approach, resulting in collections of molecular parameters that may be associated with different populations of real shell specimens. The approach is as follows: we use a Quality-Diversity algorithm, a type of black-box optimization algorithm, to explore the range of concentration profiles emerging as solutions of a molecular model, and that define growth patterns for the mechanical model. At the same time, the mechanical model is simulated over a wide range of growth patterns, resulting in a variety of spine shapes. While time-consuming, these steps only need to be performed once and then function as look-up tables. Actual pictures of shell spines can then be matched against the list of existing spine shapes, yielding a potential growth pattern which, in turn, gives us matching molecular parameters. The framework is modular, such that models can be easily swapped without changing the overall working of the method. As a demonstration of the approach, we solve specific molecular and mechanical models, adapted from available theoretical studies on molluscan shells, and apply the multiscale framework to evaluate the characteristics of spines from three distinct populations of Turbo sazae.

Characteristics of Spinal Morphology According to the Global Alignment and Proportion (GAP) Score in a Diverse, Asymptomatic Cohort: Multi-Ethnic Alignment Normative Study.

Multi-Ethnic Alignment Normative Study (MEANS) cohort: prospective, cross-sectional, multicenter. To analyze the distribution of GAP scores in the MEANS cohort and compare the spinal shape via stratification by GAP alignment category, age, and country. The GAP score has been used to categorize spinal morphology and prognosticate adult spinal deformity surgical outcomes and mechanical complications. We analyzed a large, multiethnic, asymptomatic cohort to assess the distribution of GAP scores. Four hundred sixty-seven healthy volunteers without spinal disorders were recruited in five countries. Sagittal radiographic parameters were measured via the EOS imaging system. The GAP total and constituent factor scores were calculated for each patient. Kruskal-Wallis rank sum test was performed to compare variables across groups, followed by the post hoc Games-Howell test. Fisher exact test was used to compare categorical variables. The significance level was set to P <0.05. In the MEANS cohort, 13.7% (64/467) of volunteers were ≥60 years old, and 86.3% (403/467) were <60 years old. 76.9% (359/467) was proportioned, 19.5% (91/467) was moderately disproportioned, and 3.6% (17/467) was severely disproportioned. There was no significant difference in the frequency of proportioned, moderately, or severely disproportioned GAP between subjects from different countries ( P =0.060). Those with severely disproportioned GAP alignment were on average 14.5 years older ( P =0.016), had 23.1° lower magnitude lumbar lordosis (LL) ( P <0.001), 14.2° higher pelvic tilt ( P <0.001), 13.3° lower sacral slope ( P <0.001), and 24.1° higher pelvic-incidence (PI)-LL mismatch ( P <0.001), 18.2° higher global tilt ( P <0.001) than those with proportioned GAP; thoracic kyphosis and PI were not significantly different ( P >0.05). The GAP system applies to a large, multiethnic, asymptomatic cohort. Spinal alignment should be considered on a spectrum, as 19.5% of the asymptomatic volunteers were classified as moderately disproportioned and 3.6% severely disproportioned. Radiographic malalignment does not always indicate symptoms or pathology. 3.

Reassessment of the enigmatic "Prestosuchus" loricatus (Archosauria: Pseudosuchia) from the Middle-Late Triassic of southern Brazil.

Our knowledge of the diversity and evolution of South American Triassic pseudosuchians has greatly improved in the past 15 years, due to new discoveries, but also to the revision of several historically important specimens. One of the earliest descriptions of pseudosuchians from the Triassic of Brazil stems from the classic work of Huene from the first half of the 20th century, who described several species, including such influential taxa as Rauisuchus tiradentes or Prestosuchus chiniquensis, which have recently been reviewed. The more poorly known proposed second species of Prestosuchus, P. loricatus, is the focus of the present work. The original material included some elements of the axial skeleton (cervical and caudal vertebrae, ribs, osteoderms) and the hindlimb (ischia, calcaneum, metatarsus), collected from the Dinodontosaurus Assemblage Zone of the Chiniquá area, west of São Pedro do Sul. "Prestosuchus" loricatus shows numerous differences to P. chiniquensis, including the shape of cervical neural spines, presence of epipophyses on the cervical vertebrae, presence of a pit in the iliac articulation of the ischium, lack of longitudinal furrows in the dorsolateral surface of the ischial shafts, the more slender calcaneal tuber and a less pronounced ventral pit in the calcaneum, and is thus referred to a new genus, Schultzsuchus gen. nov. Phylogenetic analysis indicates an early branching position within Poposauroidea for Schultzsuchus, making it the oldest known member of this clade in South America.

Sagittal Alignment in the Degenerative Lumbar Spine: Surgical Planning.

➤ 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.

Torsobarography: Intra-Observer Reliability Study of a Novel Posture Analysis Based on Pressure Distribution.

Postural deformities often manifest themselves in a sagittal imbalance and an asymmetric morphology of the torso. As a novel topographic method, torsobarography assesses the morphology of the back by analysing pressure distribution along the torso in a lying position. At torsobarography's core is a capacitive pressure sensor array. To evaluate its feasibility as a diagnostic tool, the reproducibility of the system and extracted anatomical associated parameters were evaluated on 40 subjects. Landmarks and reference distances were identified within the pressure images. The examined parameters describe the shape of the spine, various structures of the trunk symmetry, such as the scapulae, and the pelvic posture. The results showed that the localisation of the different structures performs with a good (ICC > 0.75) to excellent (ICC > 0.90) reliability. In particular, parameters for approximating the sagittal spine shape were reliably reproduced (ICC > 0.83). Lower reliability was observed for asymmetry parameters, which can be related to the low variability within the subject group. Nonetheless, the reliability levels of selected parameters are comparable to commercial systems. This study demonstrates the substantial potential of torsobarography at its current stage for reliable posture analysis and may pave the way as an early detection system for postural deformities.

Spinal alignment in habitual standing position and while using smartphones in healthy young adults

IntroductionA cascade of biomechanical changes occurs with postural deviations. Therefore, this study aimed to determine the trunk position and spine shape during smartphone use.MethodsBody posture was tested by the photogrammetric method in habitual standing position and while using smartphones in 39 healthy subjects of both sexes.ResultsWhile using smartphones, the trunk was shifted backwards (F(1.37) = 166.19, p = 0.0000), and the angle of the cervical spine increased in both sexes (p &lt; 0.05). Furthermore, the depth of thoracic kyphosis and lumbar lordosis increased (p &lt; 0.001), though only in the female group, but there were no differences in cervical load between groups (p &gt; 0.05).ConclusionsUsing a smartphone caused backward displacement of the upper torso in both sexes. It was also found that using a smartphone increased the depth of thoracic kyphosis and lumbar lordosis in females, which should be interpreted as a compensatory mechanism.

Diversity of Orbiniella (Orbiniidae, Annelida) in the North Atlantic and the Arctic.

In this work, the diversity of the genus Orbiniella in the Nordic Seas and the North Atlantic waters south of Iceland is studied based on the analyses of molecular markers (mitochondrial COI, 16S rDNA and nuclear ITS2) and morphological characters. Our results showed the presence of at least five genetic lineages in the studied material which could also be morphologically identified by their segmental annulation patterns, the number and the shape of acicular spines, and the length and the shape of pygidial lobes. The species name Orbiniellapetersenae is assigned to one of the lineages restricting its geographical and vertical distribution to the deep-sea areas north of Iceland and Jan Mayen, and three lineages are described as new species (i.e., Orbiniellagriegi Meca & Budaeva, sp. nov., Orbiniellamayhemi Meca & Budaeva, sp. nov., and Orbiniellaparapari Meca & Budaeva, sp. nov.) elevating the number of known species in the genus to 25. Three deep-sea species of Orbiniella in our study are reported only north of the Greenland-Iceland-Scotland Ridge, one deep-sea species found south of the ridge. A single shallow-water species is distributed along the ridge and on the Norwegian shelf.

Alobophora sandrae n. gen. n. sp. (Digenea: Caballerotrematidae) infecting Arapaima gigas sensu lato (Osteoglossiformes: Arapaimidae) with a revision of Caballerotrema, key to Caballerotrematidae, and updated phylogeny.

We propose and describe Alobophora sandrae Cajiao-Mora & Bullard n. gen., n. sp. (Digenea: Caballerotrematidae) for specimens we collected from arapaima, Arapaima gigas sensu lato (Osteoglossiformes: Arapaimidae) in the Amazon River near Leticia, Colombia. Alobophora differs from Caballerotrema Prudhoe, 1960 by lacking head collar projections and by having clustered corner spines and a narrow head collar (4-5× wider than pharynx), whereas Caballerotrema has head collar projections, lacks clustered corner spines, and has a broad head collar (7-8× wider than pharynx). We reassign Caballerotrema annulatum (Diesing, 1850) Ostrowski de Núñez & Sattmann, 2002 to the new genus, as Alobophora annulata (Diesing, 1850) Cajiao-Mora and Bullard n. comb., and provide a supplemental description of Caballerotrema brasiliense Prudhoe, 1960 based on specimens we collected from arapaima. We also examined the holotype and a paratype of Caballerotrema piscicola (Stunkard, 1960) Kostadinova & Gibson, 2001 and concluded that C. piscicola is a junior subjective synonym of C. brasiliense. Our 28S phylogeny recovered A. sandrae sister to A. annulata, with that clade sister to a clade comprising C. brasiliense and an innominate species of Caballerotrema. Caballerotrematidae was recovered sister to Echinostomatidae. We also provide a dichotomous key to caballerotrematids based on head collar projections, corner spine arrangement, proportional pharynx and head collar breadth, testes shape and arrangement, body surface spine shape and distribution, vitellarium distribution, and abundance of prostatic cells.

Predicted vs. measured paraspinal muscle activity in adolescent idiopathic scoliosis patients: EMG validation of optimization-based musculoskeletal simulations

Musculoskeletal (MSK) models offer great potential for predicting the muscle forces required to inform more detailed simulations of vertebral endplate loading in adolescent idiopathic scoliosis (AIS). In this work, simulations based on static optimization were compared with in vivo measurements in two AIS patients to determine whether computational approaches alone are sufficient for accurate prediction of paraspinal muscle activity during functional activities.We used biplanar radiographs and marker-based motion capture, ground reaction force, and electromyography (EMG) data from two patients with mild and moderate thoracolumbar AIS (Cobb angles: 21° and 45°, respectively) during standing while holding two weights in front (reference position), walking, running, and object lifting. Using a fully automated approach, 3D spinal shape was extracted from the radiographs. Geometrically personalized OpenSim-based MSK models were created by deforming the spine of pre-scaled full-body models of children/adolescents. Simulations were performed using an experimentally controlled backward approach. Differences between model predictions and EMG measurements of paraspinal muscle activity (both expressed as a percentage of the reference position values) at three different locations around the scoliotic main curve were quantified by root mean square error (RMSE) and cross-correlation (XCorr).Predicted and measured muscle activity correlated best for mild AIS during object lifting (XCorr’s ≥ 0.97), with relatively low RMSE values. For moderate AIS as well as the walking and running activities, agreement was lower, with XCorr reaching values of 0.51 and comparably high RMSE values.This study demonstrates that static optimization alone seems not appropriate for predicting muscle activity in AIS patients, particularly in those with more than mild deformations as well as when performing upright activities such as walking and running.

Rod Angulation Relationship with Thoracic Kyphosis after Adolescent Idiopathic Scoliosis Posterior Instrumentation.

Surgery to correct spinal deformities in scoliosis involves the use of contoured rods to reshape the spine and correct its curvatures. It is crucial to bend these rods appropriately to achieve the best possible correction. However, there is limited research on how the rod bending process relates to spinal shape in adolescent idiopathic scoliosis surgery. A retrospective study was conducted using a prospective multicenter scoliosis database. This study included adolescent idiopathic scoliosis patients from the database who underwent surgery with posterior instrumentation covering the T4 to T12 segments. Standing global spine X-rays were used in the analysis. The sagittal Cobb angles between T5 and T11 were measured on the spine. Additionally, the curvature of the rods between T5 and T11 was measured using the tangent method. To assess the relationship between these measurements, the difference between the dorsal kyphosis (TK) and the rod kyphosis (RK) was calculated (ΔK = TK - RK). This study aimed to analyze the correlation between ΔK and various patient characteristics. Both descriptive and statistical analyses were performed to achieve this goal. This study encompassed a cohort of 99 patients, resulting in a total of 198 ΔK measurements for analysis. A linear regression analysis was conducted, revealing a statistically significant positive correlation between the kyphosis of the rods and that of the spine (r = 0.77, p = 0.0001). On average, the disparity between spinal and rod kyphosis averaged 5.5°. However, it is noteworthy that despite this modest mean difference, there was considerable variability among the patients. In particular, in 84% of cases, the concave rod exhibited less kyphosis than the spine, whereas the convex rod displayed greater kyphosis than the spine in 64% of cases. It was determined that the primary factor contributing to the flattening of the left rod was the magnitude of the coronal Cobb angle, both before and after the surgical procedure. These findings emphasize the importance of considering individual patient characteristics when performing rod bending procedures, aiming to achieve the most favorable outcomes in corrective surgery. Although there is a notable and consistent correlation between the curvature of the spine and the curvature of the rods, it is important to acknowledge the substantial heterogeneity observed in this study. This heterogeneity suggests that individual patient factors play a significant role in shaping the outcome of spinal corrective surgery. Furthermore, this study highlights that more severe spinal curvatures in the frontal plane have an adverse impact on the shape of the rods in the sagittal plane. In other words, when the scoliosis curve is more pronounced in the frontal plane, it tends to influence the way the rods are shaped in the sagittal plane. This underscores the complexity of spinal deformities and the need for a tailored approach in surgical interventions to account for these variations among patients.

Classification of dendritic spiking neurons’ shape through clustering and machine learning techniques

A synapse is a specialized region between two adjacent neurons that allows information to be transmitted from one cell to another. The formation of these connections and transfer of signals via electrical impulses is a critical characteristic of neuronal cells. The synapse is formed by the axonal bouton on the axon side and the dendritic spine, a specialized outgrowth of the dendritic membrane, on the dendrite side. Dendritic spines exhibit diverse shapes and sizes, differing significantly across brain regions, cell categories, and animal species. Changes in dendritic spine morphology occur in neurodevelopmental and neurodegenerative ailments while also responding to external stimuli. Although deemed to facilitate synaptic plasticity, further investigation is essential for establishing the correlation between spine construction and its function. To address the issue in modern neurobiology of characterizing synapse morphology on 3D neuron images, the development of effective analytical methods is necessary. Our team has produced an open-source software solution for precise dendritic spine segmentation using 3D dendrite images. This software calculates the 10 most widely used 3D-adapted morphological features [1, 2] and enables classification and clustering of dendritic spine data sets to determine their shape. In addition to numerical features for describing the shape of a dendritic spine, researchers proposed using a histogram of chord lengths, known as the chord length distribution histogram (CLDH). This involves generating a set of random chords within the dendritic spine’s volume, connecting its outer boundaries and forming a histogram. By setting n=30 000, the probabilistic fluctuations of the histogram become insignificant. The derived metrics were then used for clustering and classifying the dataset. Classification based on predetermined morphological groups is a frequently used approach for analyzing the morphology of dendritic spines. This method involves categorizing spines into established groups such as thin, mushroom, and stubby. Experimenters generally perform classification in a semi-automated manner, leading to considerable error. We have created a spine categorization tool using a machine learning algorithm. The tool classifies spines based on a consensus reached by eight experts who manually labeled the training dataset. The accuracy of this method surpasses 77% when using classical morphological features and is comparable to expert labeling. The implementation of this approach reduces classification bias and complexity. Recent studies, including those using live microscopy in vitro and in vivo, indicate that dendritic spine shapes exhibit a continuum rather than distinct categories [3]. Therefore, it is essential to establish a dependable methodology for evaluating and examining the morphology of dendritic spines. We have created a clustering tool that establishes both the number of groups and their content based on data, rather than the experimenter’s discretion. This tool leverages the k-means and DBSCAN algorithms for its representation. Three clustering methods are presented to determine the number of clusters: the silhouette method, the elbow method, and a novel method, developed by the authors, based on the max class divergence criteria. The authors assume that cluster quality improves as clusters differ significantly in the number of mushroom/thin/stubby spine classes, as marked by experts. The benefit of this approach is that it considers the particular data type for clustering. Without this knowledge, assessing the quality of clustering is challenging. The use of the CLDH metric for clustering yielded a consistent and stable number of clusters (n=5) across all three methods described. These clusters contain dendritic spines that share similar shapes and have been validated by experts. In contrast, using classical metrics resulted in a variable cluster count ranging from n=4 to n=14. These findings suggest that the CLDH metric, with its complexity, provides enough information about synapse shape to enable precise clustering.

Evolution of sagittal spinal shape for the development of thoracic ossification of ligamentum flavum.

Thoracic ossification of the ligamentum flavum (TOLF) is a rare pathology for which limited research exists. While it is known that mechanical factors play a role in the development of TOLF, little is currently understood about the sagittal alignment and related mechanical stress involved in its development. This study aims to describe the sagittal alignment of patients with TOLF based on the pathologic evolution of the Roussouly classification. The current study evaluated the preoperative Roussouly type in consecutive patients who underwent posterior decompressive laminectomy with or without posterior screw fixation for TOLF between January 2015 and December 2021. The post-evolution sagittal alignments were analyzed using the classic Roussouly classification based on sacral slope (SS). To determine the pre-evolution Roussouly type, the patients were retrospectively classified using their individual PI and PT values. Lumbopelvic parameters and morphological index including inflection point (IP), lumbar apex (LA), and lordosis distribution index (LDI) were also evaluated. Forty-three patients (21 women and 22 men) were included; their mean age was 64.21 ± 11.01 years (range 43-81). The most affected level was T10-11 (48.83%). The mean PI was 50.81 ± 9.56°, the mean SS was 33.11 ± 8.61°and the mean PT was 17.69 ± 7.89°. According to the post-evolution Roussouly classification, type 2 shape was the most frequently observed type (n = 23, 53.5%) in the post-evolution classification while type 3 was the most common type observed in the pre-evolution classification (n = 22, 51.5% and P = .00). The level of IP and LA in type 3 moved caudally (around L2 and L4/5 level, respectively) and the LDI increased (77.98 ± 8.08%) than the normal standard value. The authors found that the majority of the patients had a false type 2 spine, which had evolved pathologically from Roussouly type 3 and exhibited increased LDI, a lowered level of IP, and a lowered level of LA. These changes of spinal shape, including the transition to long hypolordosis and increased length of the thoracic kyphosis, may have accentuated tensile stress at the lower thoracic spine and contributed to the development of TOLF.

Deep learning prediction of curve severity from rasterstereographic back images in adolescent idiopathic scoliosis.

Radiation-free systems based on dorsal surface topography can potentially represent an alternative to radiographic examination for early screening of scoliosis, based on the ability of recognizing the presence of deformity or classifying its severity. This study aims to assess the effectiveness of a deep learning model based on convolutional neural networks in directly predicting the Cobb angle from rasterstereographic images of the back surface in subjects with adolescent idiopathic scoliosis. Two datasets, comprising a total of 900 individuals, were utilized for model training (720 samples) and testing (180). Rasterstereographic scans were performed using the Formetric4D device. The true Cobb angle was obtained from radiographic examination. The best model configuration was identified by comparing different network architectures and hyperparameters through cross-validation in the training set. The performance of the developed model in predicting the Cobb angle was assessed on the test set. The accuracy in classifying scoliosis severity (non-scoliotic, mild, and moderate category) based on Cobb angle was evaluated as well. The mean absolute error in predicting the Cobb angle was 6.1° ± 5.0°. Moderate correlation (r = 0.68) and a root-mean-square error of 8° between the predicted and true values was reported. The overall accuracy in classifying scoliosis severity was 59%. Despite some improvement over previous approaches that relied on spine shape reconstruction, the performance of the present fully automatic application is below that of radiographic evaluation performed by human operators. The study confirms that rasterstereography cannot be considered a valid non-invasive alternative to radiographic examination for clinical purposes.

The shape of the tibial spines as imaging biomarker for incident knee osteoarthritis: Tibial Spines and Incident Knee Osteoarthritis

ObjectiveMorphological aspects of the tibial spines on radiography have received little attention in the evaluation of disease status or disease prediction in OA. This study explored the inter-observer reliability and associations with clinical and radiographic knee OA incidence for medial and lateral spiking, the medial and lateral edge angles, and the height of the tibial spines. DesignData from 344 middle-aged women who were overweight/obese and free of radiographic OA and knee symptoms, was used for the analyses. Outcomes were the incidence of radiographic knee OA and clinical knee OA after 30 months. Generalized Estimating Equations, to adjust for multiple measures within individuals, and a backward selection method (p > 0.1 for removal) were used to obtain prediction models. For each outcome, AUC values for the remaining factors and 95 % CI were calculated. ResultsApart from the lateral spine edge angle, all features had moderate to excellent reliability. Only the lateral spine angle showed a significant association with incident radiographic knee OA (AUC of 0.63 (95 % CI 0.53–0.73)). Medial spiking, lateral spiking, and the medial edge angle of the medial tibial spine were significantly associated with incident clinical knee OA (AUC of 0.71 (95 % CI 0.62–0.81). ConclusionsMorphological aspects of the tibial spines can reliably be obtained from radiography and should be considered in future prediction models, combined with other known predictors from patient history, physical examination, and/or imaging.

Palynotaxonomy of Centauropsis (Compositae, Vernonieae) an endemic genus from Madagascar

Centauropsis is a genus of eight species in the family Compositae, all of which are endemic to Madagascar. There is almost no information about the pollen of this genus, with only one species having its pollen described to date, which hinders systematic studies involving this genus and closely related taxa. In this study, we comprehensively characterise the pollen of Centauropsis, with details on morphology and ultrasculpture for six of the eight species of the genus. The pollen of Centauropsis is here characterised as 3-colporate, with sublophate ornamentation and nanoreticulate sexine. The species differ from each other mostly in length of the axis, morphology of the colporus endoaperture, and spine shape and size. The correlation between palynological characters and their variation within and between species was explored using principal component analyses (PCA) and cluster analyses (unweighted pair group method with arithmetic mean [UPGMA] and Euclidean distance). Full palynological descriptions, measurements and scanning electron microscopy (SEM) and light microscopy (LM) images are provided for all examined species.

STED microscopy reveals dendrite-specificity of spines in turtle cortex

Dendritic spines are key structures for neural communication, learning and memory. Spine size and shape probably reflect synaptic strength and learning. Imaging with superresolution STED microscopy the detailed shape of the majority of the spines of individual neurons in turtle cortex (Trachemys scripta elegans) revealed several distinguishable shape classes. Dendritic spines of a given class were not distributed randomly, but rather decorated significantly more often some dendrites than others. The individuality of dendrites was corroborated by significant inter-dendrite differences in other parameters such as spine density and length. In addition, many spines were branched or possessed spinules. These findings may have implications for the role of individual dendrites in this cortex.

Pelvic index: A new pelvic parameter for assessing sagittal spinal alignment

The incidence of correctional surgery for adult spinal deformity (ASD) has increased significantly over the past 2 decades. Pelvic incidence, an angular measurement, is the gold standard pelvic parameter and is used to classify spinal shapes into Roussouly types. Current literature states that restoration of the spine to its original Roussouly classification optimizes outcomes. We propose a new pelvic parameter, pelvic index, as a length measurement to complement pelvic incidence in more accurately characterizing Roussouly types. This study is a retrospective evaluation of sagittal spinal radiographs of 208 patients who were assessed by a single fellowship trained orthopedic spine surgeon between January and December 2020. Measurements included pelvic incidence, sacroacetabular distance, and L5 vertebral height. Pelvic index was calculated as the ratio of sacroacetabular distance to L5 height. Each spine was also classified into one of the Roussouly types: 1, 2, 3 anteverted pelvis (AP), 3, or 4. The 2 pelvic parameters were compared between groups to assess their ability to differentiate between Roussouly types. Of the 208 patients included, 103 (49.5%) were female and 105 (50.5%) were male. The mean pelvic incidence was 54.9 ± 12.3° and the mean pelvic index was 3.99 ± 0.38. The difference in mean pelvic index was statistically significant between types 1 and 2 (0.15; p=.046) and between types 1 and 3 AP (0.19; p=.029). It was not statistically significant between types 3 and 4 (0.05; p=.251). However, in terms of pelvic incidence, the mean difference was statistically significant only between types 3 and 4 (10.4; p<.001). Pelvic index is the ratio of the sacroacetabular distance to the height of the L5 vertebra. In conjunction with pelvic incidence, pelvic index can help to distinguish between Roussouly types 1 and 2 and between types 1 and 3 AP, the low-pelvic incidence types.

Low pelvic incidence with low lordosis and distal apex of lumbar lordosis associated with higher rates of abnormal spinopelvic mobility in patients undergoing THA.

The risk factors for abnormal spinopelvic mobility (SPM), defined as an anterior rotation of the spinopelvic tilt (∆SPT) ≥ 20° in a flexed-seated position, have been described. The implication of pelvic incidence (PI) is unclear, and the concept of lumbar lordosis (LL) based on anatomical limits may be erroneous. The distribution of LL, including a unusual shape in patients with a high lordosis, a low pelvic incidence, and an anteverted pelvis seems more relevant. The clinical data of 311 consecutive patients who underwent total hip arthroplasty was retrospectively analyzed. We analyzed the different types of lumbar shapes that can present in patients to identify their potential associations with abnormal pelvic mobility, and we analyzed the potential risk factors associated with a ∆SPT ≥ 20° in the overall population. ΔSPT ≥ 20° rates were 28.3%, 11.8%, and 14.3% for patients whose spine shape was low PI/low lordosis (group 1), low PI anteverted (group 2), and high PI/high lordosis (group 3), respectively (p = 0.034). There was no association between ΔSPT ≥ 20° and PI ≤ 41° (odds ratio (OR) 2.01 (95% confidence interval (CI)0.88 to 4.62), p = 0.136). In the multivariate analysis, the following independent predictors of ΔSPT ≥ 20° were identified: SPT ≤ -10° (OR 3.49 (95% CI 1.59 to 7.66), p = 0.002), IP-LL ≥ 20 (OR 4.38 (95% CI 1.16 to 16.48), p = 0.029), and group 1 (OR 2.47 (95% CI 1.19; to 5.09), p = 0.0148). If the PI value alone is not indicative of SPM, patients with a low PI, low lordosis and a lumbar apex at L4-L5 or below will have higher rates of abnormal SPM than patients with a low PI anteverted and high lordosis.