On the identification of the ultra-structural organization of elastic fibers and their effects on the integrity of annulus fibrosus.

Due to the complicated structure of the elastic fiber network in annulus fibrosus, existing in-silico studies either simplified or just overlooked its distribution pattern. Nonetheless, experimental and simulation results have proven that elastic fibers are of great importance to maintaining the structural integrity of annulus fibrosus and therefore to ensuring the load-bearing ability of intervertebral discs. Such needs call for a fine model. This work aims at developing a biphasic annulus fibrosus model by incorporating the accurate distribution pattern of collagen and elastic fibers. Both the structural parameters and intrinsic mechanical parameters were successfully identified using single lamella and inter-lamella microscopy anatomy and micromechanical testing data. The proposed model was then used to implement finite element simulations on various anterior and posterolateral multi-lamellae annulus fibrosus specimens. In general, simulation results agree well with available experimental and simulation data. On this basis, the effects of elastic fibers on the integrity of annulus fibrosus were further investigated. It was found that elastic fibers significantly influence the free swelling, radial stretching and circumferential shear performances of annulus fibrosus. Nonetheless, no significant effects were found for the circumferential stretching capability. The proposed biphasic model considers for the first time the distribution characteristics of elastic fibers at two scales, including both the principal orientations of all fiber families and the detailed distribution pattern within each family. Better understandings on the functions of collagen and elastic fibers can therefore be realized. To further enhance its prediction capability, the current model can be extended in the future by taking the fiber-matrix interaction as well as progressive damages into consideration.

Quantitative 23 Na-MRI of the intervertebral disk at 3 T.

Monitoring the tissue sodium content (TSC) in the intervertebral disk geometry noninvasively by MRI is a sensitive measure to estimate changes in the proteoglycan content of the intervertebral disk, which is a biomarker of degenerative disk disease (DDD) and of lumbar back pain (LBP). However, application of quantitative sodium concentration measurements in 23 Na-MRI is highly challenging due to the lower in vivo concentrations and smaller gyromagnetic ratio, ultimately yielding much smaller signal relative to 1 H-MRI. Moreover, imaging the intervertebral disk geometry imposes higher demands, mainly because the necessary RF volume coils produce highly inhomogeneous transmit field patterns. For an accurate absolute quantification of TSC in the intervertebral disks, the B1 field variations have to be mitigated. In this study, we report for the first time quantitative sodium concentration in the intervertebral disks at clinical field strengths (3 T) by deploying 23 Na-MRI in healthy human subjects. The sodium B1 maps were calculated by using the double-angle method and a double-tuned (1 H/23 Na) transceive chest coil, and the individual effects of the variation in the B1 field patterns in tissue sodium quantification were calculated. Phantom measurements were conducted to evaluate the quality of the Na-weighted images and B1 mapping. Depending on the disk position, the sodium concentration was calculated as 161.6 mmol/L-347 mmol/L, and the mean sodium concentration of the intervertebral disks varies between 254.6 ± 54 mmol/L and 290.1 ± 39 mmol/L. A smoothing effect of the B1 correction on the sodium concentration maps was observed, such that the standard deviation of the mean sodium concentration was significantly reduced with B1 mitigation. The results of this work provide an improved integration of quantitative 23 Na-MRI into clinical studies in intervertebral disks such as degenerative disk disease and establish alternative scoring schemes to existing morphological scoring such as the Pfirrmann score.

Suppression of Sost/Sclerostin and Dickkopf-1 Augment Intervertebral Disc Structure in Mice.

Intervertebral disc (IVD) degeneration is a leading cause of low back pain, characterized by accelerated extracellular matrix breakdown and IVD height loss, but there is no approved pharmacological therapeutic. Deletion of Wnt ligand competitor Lrp5 induces IVD degeneration, suggesting that Wnt signaling is essential for IVD homeostasis. Therefore, the IVD may respond to neutralization of Wnt ligand competitors sost(gene)/sclerostin(protein) and/or dickkopf-1 (dkk1). Anti-sclerostin antibody (scl-Ab) is an FDA-approved bone therapeutic that activates Wnt signaling. We aimed to (i) determine if pharmacological neutralization of sclerostin, dkk1, or their combination would stimulate Wnt signaling and augment IVD structure and (ii) determine the prolonged adaptation of the IVD to global, persistent deletion of sost. Nine-week-old C57Bl/6J female mice (n = 6-7/group) were subcutaneously injected 2×/week for 5.5 weeks with scl-Ab (25 mg/kg), dkk1-Ab (25 mg/kg), 3:1 scl-Ab/dkk1-Ab (18.75:6.25 mg/kg), or vehicle (veh). Separately, IVD of sost KO and wild-type (WT) mice (n = 8/group) were harvested at 16 weeks of age. First, compared with vehicle, injection of scl-Ab, dkk1-Ab, and 3:1 scl-Ab/dkk1-Ab similarly increased lumbar IVD height and ß-catenin gene expression. Despite these similarities, only injection of scl-Ab alone strengthened IVD mechanical properties and decreased heat shock protein gene expressions. Genetically and compared with WT, sost KO enlarged IVD height, increased proteoglycan staining, and imbibed IVD hydration. Notably, persistent deletion of sost was compensated by upregulation of dkk1, which consequently reduced the cell nuclear fraction for Wnt signaling co-transcription factor ß-catenin in the IVD. Lastly, RNA-sequencing pathway analysis confirmed the compensatory suppression of Wnt signaling and revealed a reduction of cellular stress-related pathways. Together, suppression of sost/sclerostin or dkk1 each augmented IVD structure by stimulating Wnt signaling, but scl-Ab outperformed dkk1-Ab in strengthening the IVD. Ultimately, postmenopausal women prescribed scl-Ab injections to prevent vertebral fracture may also benefit from a restoration of IVD height and health. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Origin, branching pattern, foraminal and intraspinal distribution of the human lumbar sinuvertebral nerves.

BACKGROUND CONTEXT: The lumbar sinuvertebral nerve (SVN) innervates the outer posterior intervertebral disc (IVD); it is thought to mediate discogenic low-back pain (LBP). Controversy, however, exists on its origins at higher (L1-L2) versus lower (L3-L5) lumbar levels. Additionally, lack of knowledge regarding its foraminal and intraspinal branching patterns and extensions may lead to iatrogenic damage. PURPOSE: To systematically describe the origins of the L2 and L5 SVNs, their morphological variation in the intervertebral foramen (IVF) and intraspinal distribution. STUDY DESIGN: Dissection-based study of 20 SVNs with histological confirmation in five embalmed human cadavers. METHODS: The origin, branching pattern and distribution of the L2 and L5 SVNs was investigated bilaterally in five human cadavers using dorsal and anterolateral dissection approaches. Parameters studied included somatic and/or autonomic SVN root contributions, foraminal SVN morphology and course, diameter, branching point, intraspinal distribution and IVD innervation pattern. Nerve tissue was confirmed by immunostaining for neurofilament and S100 proteins. RESULTS: The SVN and its origins was identified in all except one IVF at L2 and in all foramina at L5. At L2, the SVN arose in nearly 90% of sides from both somatic and autonomic roots and at L5 in 40% of sides. The remaining SVNs were formed by purely autonomic roots. The SVN arose from significantly more roots at L2 than L5 (3.1 ± 0.3 vs. 1.9 ± 0.3, respectively; p=.022). Four different SVN morphologies could be discerned in the L2 IVF: single filament (22%), multiple (parallel or diverging) filament (33%), immediate splitting (22%) and plexiform (22%) types, whereas the L5 SVN consisted of single (90%) and multiple (10%) filament types. SVN filaments were significantly thicker at L2 than L5 (0.48 ± 0.06 mm vs. 0.33 ± 0.02 mm, respectively; p=.043). Ascending SVN filaments coursed roughly parallel to the exiting spinal nerve root trajectory at L2 and L5. Branching of the SVN into ascending and descending branches occurred mostly intraspinal both at L2 and L5. Spinal canal distribution was also similar for L2 and L5 SVNs. Lumbar posterior IVDs were innervated by the descending branch of the parent SVN and ascending branch of the subjacent SVN. CONCLUSIONS: The SVN at L2 originates from both somatic and autonomic roots in 90% of cases and at L5 in 40% of cases. The remaining SVNs are purely autonomic. In the IVF, the L2 SVN is morphologically heterogeneous, but generally consists of numerous filaments, whereas at L5 90% contains a single SVN filament. The L2 SVN is formed by more roots and is thicker than the L5 SVN. Intraspinal SVN distribution is confined to its level of origin; lumbar posterior IVDs are innervated by corresponding and subjacent SVNs (ie, two spinal levels). CLINICAL SIGNIFICANCE: Our findings indicate that L5 discogenic LBP may be mediated both segmentally and nonsegmentally in 40% of cases and nonsegmentally in 60% of cases. Failure of lower lumbar discogenic pain treatment may be the result of only interrupting the nonsegmental pathway, but not the segmental one as well. Relating SVN anatomy to microsurgical spinal approaches may prevent iatrogenic damage to the SVN and the formation of postsurgical back pain.

Sagittal wedging of intervertebral discs and vertebral bodies in the cervical spine and their associations with age, sex and cervical lordosis: A large-scale morphological study.

Many recent studies have focused on the functional and clinical importance of cervical lordosis. However, there is little accurate knowledge of the anatomical parameters that constitute cervical lordosis (i.e., the sagittal wedging angles of intervertebral discs and vertebral bodies) and their associations with age and sex. Standing lateral cervical radiographs of 1020 subjects (424 males, 596 females) with a mean age of 36.6 ± 17.0 years (range 7-95 years) were evaluated retrospectively. Cervical lordosis, the sum of intervertebral disc wedging angles from C2/C3 to C6/C7 and the sum of vertebral body wedging angles from C3 to C7 were measured. The sum of intervertebral disc wedging and the sum of vertebral body wedging were 20.6° ± 14.7° and -12.8° ± 10.3°, respectively. The sum of intervertebral disc wedging increased significantly with age and was significantly greater in males than females, whereas there was no sex-related difference in the sum of vertebral body wedging. The sum of intervertebral disc wedging was negatively correlated with sum of vertebral body wedging. Wedging of discs contributed to C2-C7 cervical lordosis more significantly than wedging of vertebral bodies. There were moderate positive correlations between cervical lordosis and intervertebral disc wedging angles at C3/C4, C4/C5 and C5/C6; weak correlations were observed at C2/C3 and C6/C7. This study constitutes the largest currently available analysis comprehensively documenting the anatomical characteristics of sagittal wedging of intervertebral discs and vertebral bodies in the cervical spine. The findings could improve understanding of the internal architecture of cervical lordosis among clinicians.

Variation in spatial distance between the lumbar interlaminar window and intervertebral disc space during flexion-extension.

PURPOSE: Knowledge of interlaminar space is important for undertaking percutaneous endoscopic discectomy via an interlaminar approach (PED-IL). However, dynamic changes in the lumbar interlaminar space and the spatial relationship between the interlaminar space and intervertebral disc space (IDS) are not clear. The aim of this study was to anatomically clarify the changes in interlaminar space height (ILH) and variation in distance between the two spaces during flexion-extension of the lumbar spine in vitro. METHODS: First, we used a validated custom-made loading equipment to obtain neutral, flexion, and extension 3D models of eight lumbar specimens through 3D reconstruction software. Changes in ILH (ILH, IL-yH, IL-zH) and distances between the horizontal plane passing through the lowest edge of the lamina of the superior lumbar vertebrae and the horizontal plane passing through the lowest position of the trailing edge of the same-level IDS (DpLID) at L3/4, L4/5 and L5/S1 were examined on 3D lumbar models. RESULTS: We found that ILH was greater at L4/5 than at L3/4 and L5/S1 in the neutral position, but the difference was not significant. In the flexion position, ILH was significantly more than that in neutral and extension positions at L3/4, L4/5, and L5/S1. There were significantly more DpLID changes from neutral to flexion than that from neutral to extension at all levels (L3/4, L4/5, L5/S1). CONCLUSION: These findings demonstrated level-specific changes in ILH and DpLID during flexion-extension. The data may provide a better understanding of the spatial relationship between lumbar interlaminar space and IDS, and aid the development of segment-specific treatment for PED-IL.

Structure of Lumbar Intervertebral Foraminal Ligaments Based on 3-Dimensional Reconstruction Through Ultrathin Cryomilling of a Human Cadaver.

BACKGROUND: This study aimed to assess the feasibility of using the 3-dimensional (3-D) reconstruction technique based on ultrathin cryomilling to show the lumbar intervertebral foraminal ligaments in situ. METHODS: Cryomilling was performed on an embalmed human cadaver to acquire successive cross-sectional images. In each of the images, the boundaries of lumbar intervertebral foraminal ligaments and their adjacent structures were outlined, labeled, and reconstructed for 3-D modeling. The morphology, attachments, and spatial orientation of ligaments were described. RESULTS: A total of 9 ligaments in 10 lumbar intervertebral foramina (IVFs) were identified and reconstructed. These ligaments can be divided into 5 types. The IVFs were divided into 2 or 3 main portions by the first 4 types of ligaments (transforaminal ligaments, corporotransverse ligaments, "reticular" ligaments, and "Y-shaped" ligaments). The radiating ligaments (the fifth type of ligaments) attached to the surrounding structures of the IVF and were connected directly to the nerve root sleeves. Although there was no indication of neurovascular compromise in this normal specimen, these ligaments limit the space within the bony IVF such that under certain pathologic conditions (e.g., inflammation), their presence would make neurovascular compression more likely than if they were absent. CONCLUSIONS: The 3-D reconstruction technique based on ultrathin cryomilling can effectively show the lumbar intervertebral foraminal ligaments and their anatomical characteristics in situ, providing a new way to clarify the relationships between these ligaments and their adjacent structures.

Numerical implementation of an osmo-poro-visco-hyperelastic finite element solver: application to the intervertebral disc.

This work deals with the finite element (FE) implementation of a biphasic poroelastic formulation specifically developed to address the intricate behaviour of the Intervertebral Disc (IVD) and other highly hydrated soft tissues. This formulation is implemented in custom FE solver V-Biomech, being the validation performed with a lumbar IVD model, which was compared against the analogous FE model of Williams et al. and the experiments of Tyrrell et al. Good agreement with these benchmarks was achieved, meaning that V-Biomech and its novel poroelastic formulation are a viable alternative for simulation of biphasic soft tissues.

Comprehensive review on intravertebral intraspinal, intrajoint, and intradiscal vacuum phenomenon: From anatomy and physiology to pathology.

The term 'vacuum phenomenon' (VP), is characterized by gas-like density areas due to a rapid increase in the joint space volume ('acute VP') or represent a chronic gas collection. It can occur within a collapsed vertebral body, the spinal canal, joints but mainly the intervertebral disc. Studies support that VP is originated by a dynamic process involving the balance between tissues' liquid and gaseous components, influenced by the duration and the depth of mechanical and metabolic alterations, by the nature of neighboring tissues and the variability in both pressure and permeability of disc or vertebral or joint structures. Prevalence of VP in the general population is about 2%, reaching 20% in the elderly with disc degeneration. Although it's often a random finding in asymptomatic patients, VP is an eventually painful expression of disc degeneration, or disc or vertebral fracture, or bone lesions. In sporadic cases, intradiscal gas can be expelled (all-in-one or gradually), resulting in a gaseous cyst, causing pain and neurological symptoms. Considering that spontaneous resolution and recurrence after surgery are both possible, most of the authors recommend conservative treatment in patients with intradiscal and intravertebral VP; occasionally percutaneous CT(computed tomography) -guided aspiration or vertebral stabilization.

Palaeontological evidence reveals convergent evolution of intervertebral joint types in amniotes.

The intervertebral disc (IVD) has long been considered unique to mammals. Palaeohistological sampling of 17 mostly extinct clades across the amniote tree revealed preservation of different intervertebral soft tissue types (cartilage, probable notochord) seen in extant reptiles. The distribution of the fossilised tissues allowed us to infer the soft part anatomy of the joint. Surprisingly, we also found evidence for an IVD in fossil reptiles, including non-avian dinosaurs, ichthyosaurs, plesiosaurs, and marine crocodiles. Based on the fossil dataset, we traced the evolution of the amniote intervertebral joint through ancestral character state reconstruction. The IVD evolved at least twice, in mammals and in extinct diapsid reptiles. From this reptilian IVD, extant reptile groups and some non-avian dinosaurs independently evolved a synovial ball-and-socket joint. The unique birds dorsal intervertebral joint evolved from this dinosaur joint. The tuatara and some geckos reverted to the ancestral persisting notochord.

Anatomic measurement and clinical significance of the middle and lower thoracic segments in normal adults / Medición anatómica e importancia clínica de los segmentos torácico medio e inferior en adultos normales

Thoracic disc herniation (TDH) has high technical difficulty and serious complications, and the clinical anatomy of thoracic intervertebral foramen is less. Collecting 10 adult male cadavers, measuring the longitudinal diameter of the dorsal root ganglion (D1), the transverse diameter of the dorsal root ganglion (D2), horizontal sagittal diameter of the upper edge of the intervertebral disc (S1), the high of intervertebral foramen (H1), the height of articulationes costovertebrales (H2), the height of intervertebral disk (H3), the angel of the dorsal root ganglion (a). The aim of this study is to explore the safe area of middle and lower thoracic section and provide anatomical basis for the selection of operative cannula. Mastering the certain rules of the anatomical structure of the middle and lower thoracic segments, and referring to the above parameters in clinical, is conducive to the selection of the working casing during surgery.

La hernia de disco torácico (TDH) tiene una alta dificultad técnica y complicaciones graves, y la anatomía clínica del agujero intervertebral torácico es menor. Recolectando 10 cadáveres machos adultos, midiendo el diámetro longitudinal del ganglio de la raíz dorsal (D1), el diámetro transversal del ganglio de la raíz dorsal (D2), el diámetro sagital horizontal del borde superior del disco intervertebral (S1), el colmo del intervertebral agujero (H1), la altura de las articulaciones costovertebrales (H2), la altura del disco intervertebral (H3), el ángel del ganglio de la raíz dorsal (α). El objetivo de este estudio es explorar el área segura de la sección torácica media y baja y proporcionar una base anatómica para la selección de la cánula operatoria. Dominar ciertas reglas de la estructura anatómica de los segmentos torácicos medio e inferior, y referirse a los parámetros anteriores en clínica, es propicio para la selección de la carcasa de trabajo durante la cirugía.

Accuracy and Reliability of Computer-aided Anatomical Measurements for Vertebral Body and Disc Based on Computed Tomography Scans.

OBJECTIVE: To assess whether the computed tomography (CT)-based method of three-dimensional (3D) analysis (Mimics) was accurate and reliable for spine surgical anatomical measurements. METHODS: A total of 40 lumbar segments and 32 inter-vertebral discs from eigth adult male cadavers without fractures or deformities fixed with the classical formaldehyde method were included in this research on 5 June 2017. CT scans including seven dimensions: anterior height of the vertebral body (VBHa), middle height of the vertebral body (VBHm), posterior height of the vertebral body (VBHp), width of the upper endplate (EPWu), depth of the upper endplate (EPDu), anterior height of the inter-vertebral disc in the median sagittal plane (IDHa), and posterior height of the inter-vertebral disc in the median sagittal plane (IDHp). They were performed based on uniform conditions (slice thickness: 0.625 mm) using a CT scanner on 8 June 2017. Afterwards, the surgical anatomical measurements were conducted with a Vernier caliper on 12 June 2017. The computer-aided anatomical measurements were conducted by three investigators using Mimics 16.0 to perform 3D reconstructions of CT bone on 16 June 2017. Finally, the length and angle were measured with associated measurement tools, yielding a verified accuracy of 0.01 mm and 0.01°, respectively. Each measurement was repeated three times, and all anatomical data was analyzed using the statistical software and P-value < 0.05 was considered statistically significant. RESULTS: The results showed no statistically significant difference was observed between the surgical anatomical and computer-aided anatomical measurements (P > 0.05) for lumbar vertebra measurements, and the absolute difference between surgical and computer-aided data were all less than 1.0 mm (for the VBHa, VBHm, VBHp, EPWu, and EPDu were 0.12, 0.03, 0.03, 0.31, and 0.03 mm, respectively). Moreover, although the absolute differences of discs was larger than those of lumbar vertebras, no significant differences were detected between the computer-aided and surgical anatomical measurements for the IDHa, as well as IDHp in the vast majority of measurements (P = 0.543, 0.079 or 0.052 for IDHa, and P = 0.212, 0.133 or 0.042 for IDHp). In addition, excellent reliability correlation was observed between the measurements of each investigator, and the reliability coefficients in the intra-groups were all greater than 0.9 except for IDHp (reliability coefficient = 0.892). Additionally, the reliability coefficients were greater than 0.9 for the all between-group correlations, and a significant correlation was also observed. Furthermore, no statistically significant difference for three anatomical values was found in the computer-assisted measurements of the lumbar bone structure (P > 0.05). Similarly, we did not observe a statistical difference in the anatomical data of the lumbar discs from the three measures (P > 0.05). CONCLUSIONS: Computer-aided anatomical measurement for spine based on CT scans presents the high accuracy and reliability for improving spinal surgical procedures.

Morphometric Analysis of Lumbar Arteries and Relationship with Intervertebral Discs: A study of Surgical Anatomy on Human Fresh Cadavers.

AIM: To examine the morphological structure of anterior lumbar spinal region. MATERIAL AND METHODS: Fifteen fresh human cadavers were studied in our forensic medicine institution. Within the first 24 hours after death, cadavers were subject to a routine autopsy, by which the intestines were removed and the structures adjacent to the lumbar arteries (LAs) were examined. The following characteristics of the LA were examined and recorded: diameter, number of LA, intervertebral disc, and vertebral corpus relationship, and LA anatomical variations. RESULTS: In 14 of the 15 cadavers (93.3%), the first four LAs originated from the abdominal aorta. In one (6.7%) cadaver, the fourth LA originated from the right aortic trunk together with the median sacral artery (MSA), and this was observed only in the right side. In one cadaver, the first LAs emerged as a common trunk. Twelve cadavers did not have a fifth LA. In one cadaver (6.7%), the fifth LAs emerged as in a pair, distally from the origin of the MSA. Two cadavers (13.3%) had fifth LAs that emerged from the common trunk with the MSA and this occurred only on the right side. LAs which emerged from the right side of the abdominal aorta passed under the inferior vena cava. Of the first four LA, the third LA had the largest vessel diameter, and the first LA had the narrowest vessel diameter. Fifth LAs had one of the narrowest vessel diameters of all LAs. CONCLUSION: We consider that anatomical study of LAs using fresh cadavers can be useful to ensure safer anterior lumbar spinal surgeries.

Anatomy of a dinosaur-Clarification of vertebrae in vertebrate anatomy.

The flat-end surfaces of dinosaur vertebral centra led to the presumption that intervertebral discs occupied the space between their vertebrae. A set of fused hadrosaur vertebrae allowed that hypothesis to be tested. The Tyrannosaurus rex responsible for this pathology did not escape unscathed. It left behind a tooth crown that had fractured. Fragments of that tooth were scattered through the intervertebral space, evidencing that there was no solid structure to impede its movement. That eliminates the possibility of an intervertebral disc and instead proves the presence of an articular space, similar to that in modern reptiles, but at variance to what is noted in birds. While avian cervical vertebral centra appear to be separated by diarthrodial joints, the preponderance of their thoracic vertebral centra is not separated by synovial joints.

Temporomandibular joint imaging: current clinical applications, biochemical comparison with the intervertebral disc and knee meniscus, and opportunities for advancement.

Temporomandibular disorders encompass multiple pathologies of the temporomandibular joint that manifest as middle/inner ear symptoms, headache, and/or localized TMJ symptoms. There is an important although somewhat limited role of imaging in the diagnostic evaluation of temporomandibular disorders. In this manuscript, we provide a comprehensive review of TMJ anatomy, outline potentially important features of TMJ disc ultrastructure and biochemistry in comparison with the intervertebral disc and knee meniscus, and provide imaging examples of the TMJ abnormalities currently evaluable with MRI and CT. In addition, we provide an overview of emerging and investigational TMJ imaging techniques in order to encourage further imaging research based on the biomechanical alterations of the TMJ disc.

Long-term running in middle-aged men and intervertebral disc health, a cross-sectional pilot study.

PURPOSE: To measure intervertebral disc (IVD) health parameters in middle-aged long-term runners compared to matched non-physically active controls. METHODS: Seventeen males aged 44-62yr were included in the study: 9 runners with a running history of >10yr, averaging >50km/week, and eight matched non-physically active controls, the data from one participant had to be excluded. T2-relaxometry, diffusion weighted imaging, T1- and T2-weighted MR scanning, as well as T2 time mapping were performed. Morphological data relating to IVD were extrapolated. RESULTS: Compared to controls on average, runners had 20% greater IVD height (p = 0.002) and seven percentage points greater IVD-vertebral body height ratio (p = 0.001). No significant differences were observed between groups for mean(SD) IVD hydration status, as indicated by similar T2-times (runners: 94.4(11.1)ms, controls: 88.6(23.6)ms), or apparent diffusion coefficients (runners: 249.0(175.2)mm2/s, controls: 202.3(149.5)mm2/s). Average Pfirrmann score for the L5-S1 IVD was 2.2(0.7) for runners and 3.3(1.0) for controls (p = 0.026), average scores for all lumbar levels (L2-S1) were 1.9(0.2) and 2.5(0.7), respectively (p = 0.036). Anterior annulus T2-time and overall average lumbar level Pfirrmann grades were strongly correlated (r = 0.787, p = 0.021 and r = -0.704, p = 0.034, respectively) with greater distances run per week. Average lumbar level Pfirrmann grades were also strongly correlated (r = -0.823, p = 0.006) to total years of running. CONCLUSION: Middle-aged long-term endurance runners exhibit less age-related decline in their lumbar IVDs. In addition, the measures of IVD morphology appeared to be better in those who had been running for a greater number of years, as well as in those who ran a greater distance per week.

Improving anatomical stature estimation method. The relationship between living stature and intervertebral disc thickness.

Anatomical stature estimation methods reconstruct stature for skeletal specimens by adding up the heights of skeletal elements contributing to stature. In addition, these estimations factor in a certain amount of soft tissue known as "soft tissue correction". Our study focuses on the relationship between living stature and one of the major soft tissue contributors to stature: the intervertebral disc thickness/height. The purpose of this study was to clarify whether intervertebral disc thickness is greater in tall individuals and whether there is a linear correlation between stature and intervertebral disc height. To conduct this study, we utilized a subsample of the Northern Finland Birth Cohort of 1966 (n = 12,058) with known stature. We measured vertebral heights and intervertebral disc heights from low back MRI examination performed at the age of 46 years (n = 200). All subjects were considered healthy with no spinal injuries or pathologies. Our results clearly indicate that stature and intervertebral disc height have positive, statistically significant association. According to our results it is advisable to take into account the individual's skeletal height when soft tissue corrections for anatomical stature estimations are performed. Further studies utilizing full body MRI are needed to produce more accurate soft tissue corrections.

The concordance rate of L3/4 intervertebral lumbar level estimated by palpation and ultrasonography in Japanese parturients.

Background: The accurate identification of an intervertebral lumbar level is essential to avoid neuraxial anesthesia and analgesia-related spinal cord injury. It has been shown that estimation of L3/4 intervertebral lumbar level based on the intercristal line determined by palpation (palpated L3/4) is often inaccurate. However; studies evaluating intervertebral lumbar level concordance based on palpation vs. ultrasonography were conducted in Western populations (i.e. in North America and/or Europe). Radiological studies suggest that the intercristal line intersects at a lower level of the spine in Japanese women than in Western women. Therefore, we hypothesized that differences exist in intervertebral levels based on the palpated intercristal line between Asian and Western women. Herein we present the results of the first study in Japan comparing the concordance rate of L3/4 intervertebral lumbar level estimated by palpation and ultrasonography in pregnant Japanese women.Study objective: The objective of this study was to evaluate the accuracy of palpated L3/4 in Japanese parturients assessed by ultrasonography (US).Design: A prospective, observer-blinded study.Setting: Labor and delivery room at the Kitasato University Hospital, Sagamihara, Kanagawa, Japan.Patients: Sixty-three term parturients underwent induction of labor and requested neuraxial labor analgesia.Interventions: With the patients in the sitting position, an attending anesthesiologist marked the intervertebral space estimated as L3/4 based on intercristal line with palpation. Another attending anesthesiologist who was blinded to the marker performed US to identify L3/4.Results: The overall agreement rate of palpated and US L3/4 was 69.8% (44/63). Palpated L3/4 was US L2/3 in 8/63 (12.7%) and US L4/5 in 11/63 (17.5%). In comparison with women with palpated L3/4 agreed with US L3/4, women with palpated L3/4 agreed with US L2/3 were more frequently multiparous (52 vs. 100%, p < .05) and women with palpated L3/4 identified as L4/5 were younger (36 ± 4 years vs. 33 ± 4 yrs, p < .05) and gained less weight during pregnancy (10 ± 4 kg vs. 7 ± 4 kg, p < .05). The patients whose palpated L3/4 were found to be US L2/3 were all multiparous.Conclusion: The accuracy rate of palpated L3/4 intervertebral lumbar level in pregnant women included in our study was 69.8%. Pregnancy-related weight gain, parity, and maternal age can all influence an estimation of L3/4 intervertebral lumbar level by palpation. In addition, we believe that this is the first study to analyze the correlation between maternal parity and interspace estimation by palpation in pregnant women.

The Anatomical Study and Clinical Significance of the Sinuvertebral Nerves at the Lumbar Levels.

STUDY DESIGN: A dissection-based study of 10 embalmed human cadavers. OBJECTIVE: The purpose of this study was to describe the sinuvertebral nerves at the lumbar level and to discuss their possible clinical significance. SUMMARY OF BACKGROUND DATA: Discogenic low-back pain is mediated by the sinuvertebral nerves. However, the detailed descriptions of the sinuvertebral nerves at the lumbar level are lacking. METHODS: One hundred L1-L5 intervertebral foramina from 10 embalmed cadavers were studied. The presence of the sinuvertebral nerves was noted. The quantity, origin, pathway, innervation range, and spatial orientations of the sinuvertebral nerves in the L1-L5 intervertebral foramina were examined. RESULTS: A total of 450 sinuvertebral nerves were identified in the 100 lumbar intervertebral foramina; sinuvertebral nerves were observed in 100.00% of the intervertebral foramina. The sinuvertebral nerves were routinely divided into the following two types: the sinuvertebral nerve deputy branch and sinuvertebral nerve main trunk. Three hundred twelve sinuvertebral nerve deputy branches were found; on average, there were approximately 3.12 (range, 1-8) branches in each intervertebral foramen. One hundred thirty-eight sinuvertebral nerve main trunks were found, and sinuvertebral nerve main trunks were observed in 97.00% of the intervertebral foramina. The initial portion of the sinuvertebral nerve was located along the posterior-lateral edge of the disc to the spinal canal. Sixty-one (44.20%) sinuvertebral nerve main trunks originated from the starting point of the gray ramus communicans of the nerve root; 77 (55.80%) sinuvertebral nerve main trunks originated from the anterior surface of the spinal ganglia of the nerve root. CONCLUSION: This is a systematic anatomy study that describes the sinuvertebral nerve at the lumbar level and may be of clinical importance to spinal surgeons. A comprehensive understanding of the distribution of sinuvertebral nerves may lead to significant benefits for patients undergoing percutaneous endoscopic treatment for discogenic low-back pain. LEVEL OF EVIDENCE: 4.

An MRI study of solute transport in the intervertebral disc.

OBJECTIVE: Quantitative magnetic resonance imaging was used to determine partition coefficients and characteristic time constants for diffusion of MRI contrast agents in disc tissue. MATERIALS AND METHODS: Twenty-two excised equine intervertebral discs were exposed to a range of contrast agents: six to manganese chloride, eight to Magnevist (gadopentetate dimeglumine) and eight to Gadovist (gadobutrol), and uptake into the disc was quantified in T1-weighted images. RESULTS: Diffusion for all contrast agents was approximately 25% faster in the nucleus than in the outer annulus; disc-average time constants ranged from (2.28 ± 0.23) × 104 s for Gadovist (uncharged, molecular mass 605 g/mol) to (5.07 ± 0.75) × 104 s for the manganese cation (charge + 2). Disc-average partition coefficients ranged from 0.77 ± 0.04 for the anion in Magnevist (charge - 2, molecular mass 548 g/mol) to 5.14 ± 0.43 for the manganese cation. CONCLUSION: The MRI technique provides high-quality quantitative data which correspond well to theoretical predictions, allowing values for partition coefficient and time constant to be readily determined. These measurements provide information to underpin similar studies in vivo and may be used as a model for the transport of nutrients and pharmaceutical agents in the disc.