Journal articles on the topic 'Disc height'
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Zheng, Jun, and CaiLiang Shen. "Quantitative Relationship between the Degree of Lumbar Disc Degeneration and Intervertebral Disc Height in Patients with Low Back Pain." Contrast Media & Molecular Imaging 2022 (July 19, 2022): 1–6. http://dx.doi.org/10.1155/2022/5960317.
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The aim of this study is to study the relationship between the degree of lumbar disc degeneration and the height of the disc in patients with pain in the lower back and determine whether there is a dose-response relationship between the two. Eighty-five patients were examined by magnetic resonance imaging (MRI). The grade of lumbar degeneration was determined by the Pfirrmann grading system, and the intervertebral height and VAS pain scores were measured. The height difference of intervertebral discs with different degeneration levels was measured by the F test. This difference was correlated and further quantified by regression analysis. Finally, the differences intervertebral disc heights with a VAS score of 0–6 and 7–10 were observed by an independent sample t-test. The higher degree of disc degeneration in each lumbosacral segment, the lower the intervertebral disc height p ≤ 0.011 . When discs with grade 1 and grade 5 degeneration were excluded, the results remained the same p ≤ 0.034 . To quantify correlations, at each lumbar level, the disc height was reduced for each level of lumbosacral disc degeneration, and the height of disc was reduced after adjusting according to age, sex, and BMI (β range: −1.25 mm to −1.76 mm, 95% CI: −0.83 to −2.29, all p ≤ 0.002 ). Subjects with a VAS score of 7–10 had a lower intervertebral disc height than those with a VAS score of 0–6, especially with respect to total height levels at L4/5, L5/S1, and L1-S1 p ≤ 0.04 . This study showed a relationship between increased degree of intervertebral disc degeneration and decreased the disc height in patients with pain in the low back. Although the assessment of lumbar and lumbosacral level disc degeneration involves many qualitative measurements, these statistical data confirm the effectiveness of lumbosacral disc height as a continuous data measure and quantification in clinical trials and epidemiological studies.
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Agichani, Sonali Rajesh, Subhash D. Joshi, and Sharda Subhash Joshi. "Morphometric Study of Lumbar Intervertebral Discs in a Tertiary Care Centre in Central India." Journal of Evidence Based Medicine and Healthcare 8, no. 31 (August 2, 2021): 2895–99. http://dx.doi.org/10.18410/jebmh/2021/529.
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BACKGROUND The intervertebral disc (IVD) is the primary load-bearing structure in the vertebral column. It is avascular, has low metabolic rate and hence most vulnerable to damage. One of the most important causes of low back pain is the disc lesions. Hence, the present study was done to provide morphometric data of lumbar intervertebral discs in central Indians. METHODS Anterior and posterior heights of lumbar intervertebral discs were measured in (a) 10 cadavers by digital vernier calipers; (b) 120 normal, lateral view digital radiographs divided in three age groups in both the sexes, digitally. RESULTS Average heights of lumbar intervertebral discs were recorded as follows: (a) Average anterior height, measured in centimeters, was: In cadavers, L1/2-0.7922, L2/3-0.9139, L3/4-1.0611, L4/5-1.2569, and L5/S1- 1.2565 cms. On digital radiographs, L1/2-1.023, L2/3-1.262, L3/4-1.433, L4/5-1.691, L5/S1- 1.763 cms. (b) Average posterior height, measured in centimeters, was: In cadavers, L1/2-0.4624, L2/3-0.4925, L3/4-0.5872, L4/5-0.6546, and L5/S1- 0.4997cms. On digital radiographs, L1/2-0.78475, L2/3-0.875917, L3/4-0.900083, L4/5- 0.92375, and L5/S1-0.795 cms. CONCLUSIONS Average anterior heights are more than posterior heights. Average anterior and posterior heights increase from L1/2 upto L4/5, then decrease at L5/S1. But in digital radiographs, average anterior height increases from L1/2 to L5/S1. The difference in measurements of average anterior heights of L1/2 disc is found to be statistically significant with respect to age. Gender difference is statistically significant at different disc levels in different age groups. The present study will help to generate baseline data to detect abnormality and to make population specific prosthesis for treatment of disc lesions. KEYWORDS Morphometry, Lumbar Intervertebral Discs
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Wilke, Hans-Joachim, Sinead Kavanagh, Sylvia Neller, Christian Haid, and Lutz Eberhart Claes. "Effect of a prosthetic disc nucleus on the mobility and disc height of the L4–5 intervertebral disc postnucleotomy." Journal of Neurosurgery: Spine 95, no. 2 (October 2001): 208–14. http://dx.doi.org/10.3171/spi.2001.95.2.0208.
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Object. Current procedures for treatment of degenerative disc disease may not restore flexibility or disc height to the intervertebral disc. Recently, a prosthetic device, intended to replace the degenerated nucleus pulposus, was developed. In this biomechanical in vitro test the authors study the effect of implanting a prosthetic nucleus in cadaveric lumbar intervertebral discs postnucleotomy and determine if the flexibility and disc height of the L4–5 motion segment is restored. Methods. The prosthetic disc nucleus device consists of two hydrogel pellets, each enclosed in a woven polyethylene jacket. Six human cadaveric lumbar motion segments (obtained in individuals who, at the time of death, were a mean age of 56.7 years) were loaded with moments of ± 7.5 Nm in flexion—extension, lateral bending, and axial rotation. The following states were investigated: intact, postnucleotomy, and after device implantation. Range of motion (ROM) and neutral zone (NZ) measurements were determined. Change in disc height from the intact state was measured after nucleotomy and device implantation, with and without a 200-N preload. Conclusions. Compared with the intact state (100%), the nucleotomy increased the ROM in flexion—extension to 118%, lateral bending to 112%, and axial rotation to 121%; once the device was implanted the ROM was reduced to 102%, 88%, and 90%, respectively. The NZ increased the ROM to 210%, lateral bending to 173%, and axial rotation to 107% after nucleotomy, and 146%, 149%, 44%, respectively, after device implantation. A 200-N preload reduced the intact and postnucleotomy disc heights by approximately 1 mm and 2 mm, respectively. The original intact disc height was restored after implantation of the device. The results of the cadaveric L4–5 flexibility testing indicate that the device can potentially restore ROM, NZ, and disc height to the denucleated segment.
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Jeong, Jae-Gyeong, Sungwook Kang, Gu-Hee Jung, Mingoo Cho, Hyunsoo Kim, Kyoung-Tae Kim, Dong-Hee Kim, and Jong-Moon Hwang. "Biomechanical Effect of Disc Height on the Components of the Lumbar Column at the Same Axial Load: A Finite-Element Study." Journal of Healthcare Engineering 2022 (October 25, 2022): 1–13. http://dx.doi.org/10.1155/2022/7069448.
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Intervertebral discs are fibrocartilage structures, which play a role in buffering the compression applied to the vertebral bodies evenly while permitting limited movements. According to several previous studies, degenerative changes in the intervertebral disc could be accelerated by factors, such as aging, the female sex, obesity, and smoking. As degenerative change progresses, the disc height could be reduced due to the dehydration of the nucleus pulposus. This study aimed to quantitatively analyze the pressure that each structure of the spine receives according to the change in the disc height and predict the physiological effect of disc height on the spine. We analyzed the biomechanical effect on spinal structures when the disc height was decreased using a finite-element method investigation of the lumbar spine. Using a 3D FE model, the degree and distribution of von-Mises stress according to the disc height change were measured by applying the load of four different motions to the lumbar spine. The height was changed by dividing the anterior and posterior parts of the disc, and analysis was performed in the following four motions: flexion, extension, lateral bending, and axial rotation. Except for a few circumstances, the stress applied to the structure generally increased as the disc height decreased. Such a phenomenon was more pronounced when the direction in which the force was concentrated coincided with the portion where the disc height decreased. This study demonstrated that the degree of stress applied to the spinal structure generally increases as the disc height decreases. The increase in stress was more prominent when the part where the disc height was decreased and the part where the moment was additionally applied coincided. Disc height reduction could accelerate degenerative changes in the spine. Therefore, eliminating the controllable risk factors that cause disc height reduction may be beneficial for spinal health.
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Tumialán, Luis M., Justin C. Clark, Laura A. Snyder, and Frederick F. Marciano. "Provisional Ipsilateral Expandable Rod for Disc Space Distraction in Minimally Invasive Transforaminal Lumbar Interbody Fusion: Operative Technique." Operative Neurosurgery 10, no. 4 (August 25, 2014): 555–64. http://dx.doi.org/10.1227/neu.0000000000000542.
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Abstract BACKGROUND: Lumbar disc degeneration may be so advanced and asymmetrical that transforaminal access to the interbody space is limited. The extent of collapse may compromise the capacity to restore disc height and coronal balance in minimally invasive approaches. Although a variety of distractors are available for open approaches, currently there is no feasible distractor that is functional within a minimally invasive retractor. OBJECTIVE: To describe the development of a provisional ipsilateral expandable rod for use in minimally invasive surgery for transforaminal lumbar interbody fusions to optimize access to the disc space, thereby facilitating placement of an interbody spacer. METHODS: The authors report the clinical and radiographic data for 30 patients (3 open and 27 minimally invasive surgeries) with advanced degenerative disc disease in whom a provisional ipsilateral expandable rod was used to restore coronal balance and maintain disc height for interbody preparation and placement. Preoperative disc heights were measured, and the height of interbody spacer recorded. Mean restoration of disc heights was calculated. RESULTS: The provisional ipsilateral expandable rod was successfully applied in both open exposures and within a minimally invasive retractor. The mean preoperative disc height was 4.9 mm (range, 1-9 mm), the mean height of the spacer inserted was 11.1 mm (range, 8-15 mm), and the mean increase in disc height was 6.2 mm (range, 5-11 mm). CONCLUSION: A provisional ipsilateral expandable rod is feasible in either minimally invasive or open approaches. It has the capacity to maintain the disc height achieved by paddle distractors. This facilitates both the disc preparation and optimizes restoration of disc height and interbody spacer placement.
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Liu, Ming Yu, Yin Bang Liu, and Li Chun Jiang. "Variation of Wood Density in Larch in Northeast of China." Advanced Materials Research 487 (March 2012): 38–42. http://dx.doi.org/10.4028/www.scientific.net/amr.487.38.
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Wood density was investigated in seven dahurian larch (Larix gmelinii Rupr.) trees grown in northeastern China. Six discs (about 5 cm thick) were cut from each tree (i.e. from the root stem, at breast height (1.3m), and at 20%, 40%, 60%, and 80% of the total height). For each disc, a thick sliver with parallel sides was cut out along the diameter of the disc. The sliver was about 40-mm thick, with the pith located in the middle. Eight small pieces were cut from the sliver with equal distance from pith to bark. Wood density of small piece was obtained using water displacement method. Significant variation in wood density was observed among sections for different heights. Wood density increases from pith to bark for all height categories and decreases from the stump to top of the tree height.
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Ding, Huaili, Lijun Liao, Peichun Yan, Xiaolin Zhao, and Min Li. "Three-Dimensional Finite Element Analysis of L4-5 Degenerative Lumbar Disc Traction under Different Pushing Heights." Journal of Healthcare Engineering 2021 (July 19, 2021): 1–9. http://dx.doi.org/10.1155/2021/1322397.
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Objective. To study and analyze the changes of intervertebral foramen height and area of the degenerative L4-5 intervertebral disc under different pushing heights by the finite element method. Methods. CT and MRI images of T12-S1 segments were obtained from a healthy volunteer who met the inclusion criteria. A DR machine was used to capture images of the lumbar lateral section before and after simultaneous pushing of the L4 and L5 spinous processes by manipulation called Daogaijinbei, and the measurement showed that the displacement changes of L4 and L5 were both approximately 10 cm, so the pushing height was set at 0–10 cm. A three-dimensional finite element model of the entire normal lumbar spine was established using Mimics 16.0, Geomagic Studio 2014, Hypermesh 13.0, MSC.Patran 2012, and so on. The disc height and nucleus area of the lumbar disc of the normal entire lumbar disc model were adjusted to establish models of the L4-5 disc with mild, moderate, and severe degeneration. Changes of disc height and area of the L4-5 degenerative intervertebral disc under different pushing heights were calculated. Results. The size of the L4-5 intervertebral foramen was analyzed from the height and area of the intervertebral foramen, and the results showed the following: (1) as for the normal lumbar disc and a lumbar of the L4-5 disc with mild and moderate degeneration, the height of the L4-5 intervertebral foramen and its area both increased during pushing between 0 and 8 cm. After the pushing height reached 8 cm, the height and area of the L4-5 intervertebral foramen gradually became stable; (2) as for the L4-5 disc with severe degeneration, during the process of pushing, the height and area of the L4-5 intervertebral foramen increased slightly, but this change was not obvious. Conclusions. After the spinal manipulation, the sizes of the L4-5 intervertebral foramen of the L4-5 disc with mild and moderate degeneration were significantly larger than those before pushing; in contrast, the size of L4-5 intervertebral foramen of the L4-5 disc with severe lumbar degeneration was not significantly changed.
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Friedmann, Andrea, Andre Baertel, Christine Schmitt, Christopher Ludtka, Javorina Milosevic, Hans-Joerg Meisel, Felix Goehre, and Stefan Schwan. "Intervertebral Disc Regeneration Injection of a Cell-Loaded Collagen Hydrogel in a Sheep Model." International Journal of Molecular Sciences 22, no. 8 (April 19, 2021): 4248. http://dx.doi.org/10.3390/ijms22084248.
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Degenerated intervertebral discs (IVDs) were treated with autologous adipose-derived stem cells (ASC) loaded into an injectable collagen scaffold in a sheep model to investigate the implant’s therapeutic potential regarding the progression of degeneration of previously damaged discs. In this study, 18 merino sheep were subjected to a 3-step minimally invasive injury and treatment model, which consisted of surgically induced disc degeneration, treatment of IVDs with an ASC-loaded collagen hydrogel 6 weeks post-operatively, and assessment of the implant’s influence on degenerative tissue changes after 6 and 12 months of grazing. Autologous ASCs were extracted from subcutaneous adipose tissue and cultivated in vitro. At the end of the experiment, disc heights were determined by µ-CT measurements and morphological tissue changes were histologically examined.Histological investigations show that, after treatment with the ASC-loaded collagen hydrogel implant, degeneration-specific features were observed less frequently. Quantitative studies of the degree of degeneration did not demonstrate a significant influence on potential tissue regeneration with treatment. Regarding disc height analysis, at both 6 and 12 months after treatment with the ASC-loaded collagen hydrogel implant a stabilization of the disc height can be seen. A complete restoration of the intervertebral disc heights however could not be achieved.The reported injection procedure describes in a preclinical model a translational therapeutic approach for degenerative disc diseases based on adipose-derived stem cells in a collagen hydrogel scaffold. Further investigations are planned with the use of a different injectable scaffold material using the same test model.
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Tao, Youping, Fabio Galbusera, Frank Niemeyer, René Jonas, Dino Samartzis, Daniel Vogele, and Hans-Joachim Wilke. "The impact of age, sex, disc height loss and T1 slope on the upper and lower cervical lordosis: a large-scale radiologic study." European Spine Journal 30, no. 9 (July 30, 2021): 2434–42. http://dx.doi.org/10.1007/s00586-021-06933-x.
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Abstract Purpose To clarify the relative influence of age, sex, disc height loss and T1 slope on upper (Occiput-C2) and lower cervical lordosis (C2–C7). Methods Standing lateral cervical radiographs of 865 adult subjects were evaluated. The presence and severity of disc height loss from C2/C3 to C6/C7 (a total of 4325 discs) were assessed using a validated grading system. The total disc height loss score for each subject was calculated as the sum of the score of each disc space. Sagittal radiographic parameters included: occipital slope, occiput-C2 (Oc-C2) lordosis, C2–C7 lordosis and T1 slope. Multivariable regression analyses were performed to examine the relative influence of the multiple factors on upper and lower cervical lordosis. Results This study included 360 males and 505 females, with a mean age of 40.2 ± 16.0 years (range, 20–95 years). Linear multivariate regression analyses showed that greater age, male sex, greater T1 slope were each found to be significantly and independently associated with greater C2–C7 lordosis, whereas total disc height loss score was negatively associated with C2–C7 lordosis. T1 slope had the most independent influence on C2–C7 lordosis among these factors. Age, sex and disc height loss were not independently associated with Oc-C2 lordosis. Conclusions Results from our large-scale radiologic analysis may enhance the understanding of the factors that affect cervical lordosis, indicating that age, sex, disc height loss and T1 slope were each independently associated with C2–C7 lordosis. However, age, sex and disc height loss were not independently associated with upper cervical lordosis.
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Sloan, Stephen, Christoph Wipplinger, Sirtac Kirnaz, Rodrigo Navarro-Ramirez, Antonella Schivinato, Roger Härtl, and Lawrence Bonassar. "3013 Combined Annulus Fibrosus and Nucleus Pulposus Repair Prevents Degeneration in the Ovine Lumbar Spine." Journal of Clinical and Translational Science 3, s1 (March 2019): 6. http://dx.doi.org/10.1017/cts.2019.17.
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OBJECTIVES/SPECIFIC AIMS: The objective of this study is to assess the efficacy of combined AF and NP repairs to prevent degenerative changes and restore native disc morphology in an in vivo large animal model. We hypothesize that combined repairs will prevent disc degeneration following injury to a greater extent than the individual repairs after 6 weeks in vivo, as demonstrated through disc height measurements and disc morphology. METHODS/STUDY POPULATION: A total of 8 skeletally mature female Finn sheep were used in this study. Following a previously described method, IVDs from L1 to L6 of the lumbar spine were exposed using a lateral access, extraperitoneal approach5. IVDs were randomized into 5 treatment groups: 1) intact discs, 2) discs injured via a 3 cm x 1 cm box annulotomy and partial nucleotomy, 3) injury followed by a high density collagen (HDC) AF patch, 4) injury followed by injection of a modified hyaluronic acid (HA) into the NP, and 5) injury followed by both the HDC AF patch and HA NP injection. The HDC treatment was 15 mg/mL type-I collagen mixed with 0.06mM riboflavin, injected at the defect site and crosslinked in situ with blue light. The NP injection was HA modified with C16 side chains to increase the viscosity of the hydrogel (HYADD 4®)6. At 6 weeks post-operatively, sheep were sacrificed and had 3T magnetic resonance images (MRI) taken of their lumbar spine. Disc height analysis and Pfirrmann grading were performed on each segment using MR images. Additionally, quantitative MRI analyses were performed using a custom MATLAB algorithm that segments NP from the surrounding tissue and directly measures the NP volume. ANOVA with Tukey’s HSD was used to determine statistical significance between groups for disc height and quantitative MRI analyses, and the Kruskal-Wallis test with Mann-Whitney tests was used to statistically analyze Pfirrmann Grades. All animal use followed approved IACUC protocol. RESULTS/ANTICIPATED RESULTS: As shown in axial MR images (Figure 1A), intact discs had hyperintense NP with a distinct border to the AF. The discs receiving injury with no treatment had hypointense NP with no distinct border between the AF and NP. Individual and combined treatment with the HA NP injection and HDC AF patch appeared to preserve the hyperintense NP signal and AF/NP border. Intact control discs were not degenerated and had an average Pfirrmann grade of 1 (Figure 1B), while injured, untreated discs had significant degeneration with an average Pfirrmann grade of 3. Discs receiving the HA NP injection and collagen AF patch individually showed fewer signs of degeneration than the injured alone, and the combined treatment resulted in the least amount of degeneration with Pfirrmann grades not significantly different than the intact controls. Disc height index confirmed the trends seen in the Pfirrmann grades (Figure 1C), where injured discs lost 20% of the intact disc height, the individual NP and AF repairs restored 5-10% of intact disc height, and the combined repairs preserved 90% of the intact disc height. The NP voxel count of all treatment groups were similar to the intact controls (Figure 1D). DISCUSSION/SIGNIFICANCE OF IMPACT: The objective of this study was to determine how combined AF and NP can prevent degenerative changes to the disc in a large animal in vivo model. Pfirrmann grading and disc height index results show that the greatest preservation of disc morphology was seen with combined AF and NP repairs, while the individual strategies prevented degenerative changes better than injury with no treatment. It appears the HA NP injection restores lost water content to the disc following injury, and the AF collagen patch plays a role in maintaining the NP repair within the disc. This is the first study to our knowledge to attempt combined AF and NP repairs in an in vivo large animal model. Combining NP and AF repairs leads to significantly improved outcomes following disc injury, which warrants the translation of combined repairs into the clinic to improve patient outcomes with degenerative disc disease involving NP and AF.
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Rabago, Ian, and Zhaohuan Zhu. "Constraining protoplanetary disc accretion and young planets using ALMA kinematic observations." Monthly Notices of the Royal Astronomical Society 502, no. 4 (February 16, 2021): 5325–39. http://dx.doi.org/10.1093/mnras/stab447.
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ABSTRACT Recent ALMA molecular line observations have revealed 3D gas velocity structure in protoplanetary discs, shedding light on mechanisms of disc accretion and structure formation. (1) By carrying out viscous simulations, we confirm that the disc’s velocity structure differs dramatically using vertical stress profiles from different accretion mechanisms. Thus, kinematic observations tracing flows at different disc heights can potentially distinguish different accretion mechanisms. On the other hand, the disc surface density evolution is mostly determined by the vertically integrated stress. The sharp disc outer edge constrained by recent kinematic observations can be caused by a radially varying α in the disc. (2) We also study kinematic signatures of a young planet by carrying out 3D planet–disc simulations. The relationship between the planet mass and the ‘kink’ velocity is derived, showing a linear relationship with little dependence on disc viscosity, but some dependence on disc height when the planet is massive (e.g. 10MJ). We predict the ‘kink’ velocities for the potential planets in DSHARP discs. At the gap edge, the azimuthally averaged velocities at different disc heights deviate from the Keplerian velocity at similar amplitudes, and its relationship with the planet mass is consistent with that in 2D simulations. After removing the planet, the azimuthally averaged velocity barely changes within the viscous time-scale, and thus the azimuthally averaged velocity structure at the gap edge is due to the gap itself and not directly caused to the planet. Combining both axisymmetric kinematic observations and the residual ‘kink’ velocity is needed to probe young planets in protoplanetary discs.
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Han, Yinuo, Mark C. Wyatt, and Luca Matrà. "rave: a non-parametric method for recovering the surface brightness and height profiles of edge-on debris discs." Monthly Notices of the Royal Astronomical Society 511, no. 4 (February 11, 2022): 4921–36. http://dx.doi.org/10.1093/mnras/stac373.
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ABSTRACT Extrasolar analogues of the Solar System’s Kuiper belt offer unique constraints on outer planetary system architecture. Radial features such as the sharpness of disc edges and substructures such as gaps may be indicative of embedded planets within a disc. Vertically, the height of a disc can constrain the mass of embedded bodies. Edge-on debris discs offer a unique opportunity to simultaneously access the radial and vertical distribution of material; however, recovering either distribution in an unbiased way is challenging. In this study, we present a non-parametric method to recover the surface brightness profile (face-on surface brightness as a function of radius) and height profile (scale height as a function of radius) of azimuthally symmetric, edge-on debris discs. The method is primarily designed for observations at thermal emission wavelengths, but is also applicable to scattered light observations under the assumption of isotropic scattering. By removing assumptions on underlying functional forms, this algorithm provides more realistic constraints on disc structures. We also apply this technique to Atacama Large Millimeter/submillimeter Array observations of the AU Mic debris disc and derive a surface brightness profile consistent with estimates from parametric approaches, but with a more realistic range of possible models that is independent of parametrization assumptions. Our results are consistent with a uniform scale height of 0.8 au, but a scale height that increases linearly with radius is also possible.
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Kroupa, Pavel. "The Apparent Galactic Disc Scale Height." International Astronomical Union Colloquium 135 (1992): 228–30. http://dx.doi.org/10.1017/s0252921100006448.
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Abstract For stars fainter than Mv ≈ 6 the density distribution perpendicular to the Galactic midplane can be approximated by an exponential fall-off with a scale height of about 270 pc. We show that even if in fact constant an apparent decrease of the scale height to about 150 pc for stars with Mv ≈ 17 can be expected if all ‘stars’ measured in the photographic surveys are unresolved binaries. In principle measurements of the apparent scale-height allow the study of the mass-ratio distribution and the proportion among ‘stars’ of binary systems.
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Patra, Narendra Nath. "Theoretical modelling of two-component molecular discs in spiral galaxies." Astronomy & Astrophysics 638 (June 2020): A66. http://dx.doi.org/10.1051/0004-6361/201936483.
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As recent observations of the molecular discs in spiral galaxies point to the existence of a diffuse, low-density thick molecular disc along with the prominent thin one, we investigate the observational signatures of this thick disc by theoretically modelling two-component molecular discs in a sample of eight nearby spiral galaxies. Assuming a prevailing hydrostatic equilibrium, we set up and solved the joint Poisson’s-Boltzmann equation to estimate the three-dimensional distribution of the molecular gas and the molecular scale height in our sample galaxies. The molecular scale height in a two-component molecular disc is found to vary between 50 and 300 pc, which is higher than what is found in a single-component disc. We find that this scale height can vary significantly depending on the assumed thick disc molecular gas fraction. We also find that the molecular gas flares as a function of the radius and follows a tight exponential law with a scale length of (0.48 ± 0.01)r25. We used the density solutions to produce the column density maps and spectral cubes to examine the ideal observing conditions to identify a thick molecular disc in galaxies. We find that unless the molecular disc is an edge-on system and imaged with a high spatial resolution (≲100 pc), it is extremely hard to identify a thick molecular disc in a column density map. The spectral analysis further reveals that at moderate to high inclination (i ≳ 40°), spectral broadening can fictitiously introduce the signatures of a two-component disc into the spectral cube of a single-component disc. Hence, we conclude that a low inclination molecular disc imaged with high spatial resolution would serve as the ideal site for identifying the thick molecular disc in galaxies.
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Kaliya-Perumal, Arun-Kumar, Tamara Lee Ting Soh, Mark Tan, and Jacob Yoong-Leong Oh. "Factors Influencing Early Disc Height Loss Following Lateral Lumbar Interbody Fusion." Asian Spine Journal 14, no. 5 (October 31, 2020): 601–7. http://dx.doi.org/10.31616/asj.2019.0332.
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Study Design: Retrospective radiological analysis.Purpose: To analyze the factors influencing early disc height loss following lateral lumbar interbody fusion (LLIF).Overview of Literature: Postoperative disc height loss can occur naturally as a result of mechanical loading. This phenomenon is enabled by the yielding of the polyaxial screw heads and settling of the cage to the endplates. When coupled with cage subsidence, there can be significant reduction in the foraminal space which ultimately compromises the indirect decompression achieved by LLIF.Methods: Seventy-two cage levels in 37 patients aged 62±10.2 years who underwent single or multilevel LLIF for degenerative spinal conditions were selected. Their preoperative and postoperative follow-up radiographs were used to measure the anterior disc height (ADH), posterior disc height (PDH), mean disc height (MDH), disc space angle (DSA), and segmental angle. Correlations between the loss of disc height and several factors, including age, construct length, preoperative lordosis, postoperative lordosis, disc height, cage dimensions, and cage position, were analyzed.Results: We found that the lateral interbody cages significantly increased ADH, PDH, MDH, and DSA after surgery (<i>p</i> <0.0001). However, there was a loss of disc height over time. All postoperative disc height parameters, especially the amount of increase in MDH (<i>r</i> =0.413, <i>p</i> <0.0001) after surgery, showed a significant positive association with early disc height loss. The levels demonstrating a significant (≥25%) height loss were those that exhibited a substantial height increase (128.3%, 4.6±3.0 to 10.5±5.6 mm) postoperatively. However, the levels that showed less than 25% height loss were those that exhibited, on average, only a 57.4% height increase post-operatively.Conclusions: The greater the postoperative increase in disc height, the greater the disc height loss throughout early follow-up. Therefore, achieving an optimal disc height rather than overcorrection is an important surgical strategy to adopt when performing LLIF.
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Aniyan, S., A. A. Ponomareva, K. C. Freeman, M. Arnaboldi, O. E. Gerhard, L. Coccato, K. Kuijken, and M. Merrifield. "Resolving the Disc–Halo Degeneracy – II: NGC 6946." Monthly Notices of the Royal Astronomical Society 500, no. 3 (October 9, 2020): 3579–93. http://dx.doi.org/10.1093/mnras/staa3106.
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ABSTRACT The mass-to-light ratio (M/L) is a key parameter in decomposing galactic rotation curves into contributions from the baryonic components and the dark halo of a galaxy. One direct observational method to determine the disc M/L is by calculating the surface mass density of the disc from the stellar vertical velocity dispersion and the scale height of the disc. Usually, the scale height is obtained from near-IR studies of edge-on galaxies and pertains to the older, kinematically hotter stars in the disc, while the vertical velocity dispersion of stars is measured in the optical band and refers to stars of all ages (up to ∼10 Gyr) and velocity dispersions. This mismatch between the scale height and the velocity dispersion can lead to underestimates of the disc surface density and a misleading conclusion of the submaximality of galaxy discs. In this paper, we present the study of the stellar velocity dispersion of the disc galaxy NGC 6946 using integrated star light and individual planetary nebulae as dynamical tracers. We demonstrate the presence of two kinematically distinct populations of tracers that contribute to the total stellar velocity dispersion. Thus, we are able to use the dispersion and the scale height of the same dynamical population to derive the surface mass density of the disc over a radial extent. We find the disc of NGC 6946 to be closer to maximal with the baryonic component contributing most of the radial gravitational field in the inner parts of the galaxy (Vmax(bar) = 0.76(±0.14)Vmax).
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Daly, Chris D., Peter Ghosh, Tanya Badal, Ronald Shimmon, Ian Ghosh, Graham Jenkin, David A. Oehme, et al. "333 Intervertebral Disc Repair Following Microdiscectomy Mediated by Pentosan Polysulfate Primed Mesenchymal Progenitor Cells in an Ovine Model." Neurosurgery 64, CN_suppl_1 (August 24, 2017): 274. http://dx.doi.org/10.1093/neuros/nyx417.333.
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Abstract INTRODUCTION Lumbar microdiscectomy treats neural compression but fails to halt disc degeneration. Consequently, 10 20% of patients develop debilitating back pain and approximately 15% undergo further surgical intervention. In-vitro pre-incubation of mesenchymal precursor cells (MPCs) with pentosan polysulfate (PPS), enhances viability and chondrogenic differentiation, but inhibits osteogenesis. This study investigated the potential of PPS primed mesenchymal precursor cells (pMPCs) in a gelatin scaffold to facilitate disc repair in an ovine model. METHODS Eighteen adult ewes underwent pre-operative 3T MRI followed by lumbar microdiscectomy at two levels. Sheep were randomized into three groups. The injured control (IC) group received no further treatment; the MPC group were implanted with non-primed MPC + scaffold; the pMPC group received the pMPC + scaffold. Necropsies were performed at six months. Analysis consisted of 3T and 9.4T MRI, gross morphological, histological and biochemical analysis for proteoglycans, collagen and DNA content. RESULTS >MPC and pMPC discs demonstrated significantly reduced disc height loss (P < 0.05) and reduced Pfirrmann grades (P < 0.001) relative to IC discs. pMPC disc segments were significantly less degenerate than IC discs on gross morphology. Proteoglycan content of pMPC discs was significantly greater than IC discs and not significantly different to controls for the injured annulus fibrosus (AF) region and nucleus pulposus (NP) region contralateral to the injury. DNA content for pMPC discs was significantly less than IC discs for the NP & AF injury and adjacent regions. Histological analysis demonstrated increased organization and decreased degeneration in pMPC discs while MPC discs displayed increased vascular infiltration. CONCLUSION pMPCs post microdiscectomy reduced disc degeneration, improved disc height and matrix organization, NP proteoglycan content and histological degeneration relative to microdiscectomy alone. This suggests a potential therapeutic application of pMPCs in promoting disc repair and reducing the incidence of low back pain and further surgery following microdiscectomy.
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Yoon, Seung-Hwan, Masashi Miyazaki, Soon-Woo Hong, Ben Tow, Yuichiro Morishita, Ming Hu, Sung-Joon Ahn, and Jeffrey C. Wang. "A porcine model of intervertebral disc degeneration induced by annular injury characterized with magnetic resonance imaging and histopathological findings." Journal of Neurosurgery: Spine 8, no. 5 (May 2008): 450–57. http://dx.doi.org/10.3171/spi/2008/8/5/450.
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Object Appropriate animal models of disc degeneration are critical for the study of proposed interventions as well as to further delineate the degenerative process. The purpose of this study was to characterize a porcine model for disc degeneration confirmed on magnetic resonance (MR) imaging studies and histological analysis. Methods Twelve miniature pigs were used (weight 48–65 kg) to study degeneration in the lumbar spine. Under fluoroscopic guidance, the disc was percutaneously punctured with a 3.2-mm-diameter trephine to a 5-mm depth into the annulus fibrosus. Control and experimental levels were randomized among 6 levels in the lumbar spine. The unlesioned spinal levels were used as controls and were compared with lesioned levels. Magnetic resonance imaging grading and disc height were serially recorded preoperatively, and at 5, 8, 19, 32, and 39 weeks postoperatively. The animals were killed in groups of 3 at 7, 18, 32, and 41 weeks postinjury, and the discs were examined histopathologically. Results Consistent, sequential, and progressive degeneration of the annular injury was observed on MR imaging and histopathological studies from the time of injury to the final time point. The disc height and the disc height index also sequentially decreased from the time of the injury in a consistent manner. The uninjured control levels did not show any progressive degeneration and maintained their normal state. Conclusions Based on MR imaging and histopathological findings, the authors demonstrated and characterized a reliable model of sequential disc degeneration in miniature pigs with percutaneous injury to the annulus fibrosus. In the early stages, as soon as 5 weeks after injury, significant disc degeneration was seen on MR imaging grading with decreases in disc height. This degeneration did not improve by the final time point of 39 weeks.
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Bohl, Michael A., Randall J. Hlubek, Michael A. Mooney, Kristina M. Chapple, Mark C. Preul, Steve W. Chang, Jay D. Turner, and U. Kumar Kakarla. "Disc Geometry is an Accurate Predictor of Lordotic Correction in the Thoracolumbar Spine Following Schwab Grade 2 Osteotomy: A Cadaveric Study and Biomechanical Analysis of Disc Space Changes Following Lordotic Correction." Operative Neurosurgery 17, no. 3 (December 13, 2018): 303–10. http://dx.doi.org/10.1093/ons/opy362.
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Abstract BACKGROUND Posterior column osteotomy (PCO) is a powerful technique for correcting lordosis, but the surgical literature lacks objective evidence on preoperative predictors of achievable lordotic correction following PCO. OBJECTIVE To measure the correlation between disc geometry and achievable lordotic correction following Schwab grade 2 osteotomies and to describe geometric changes to disc space following lordotic correction. METHODS Schwab grade 2 osteotomies were performed from T1 to S1 in 5 cadavers. Lateral radiographs were taken before and after posterior column compression. Anterior disc height (ADH), middle disc height (MDH), posterior disc height (PDH), and lordotic angles were measured. The association between disc height and lordotic correction was analyzed using linear regression. RESULTS For all spinal levels (n = 79), PDH was most strongly correlated with lordotic correction (r = 0.72, P < .001). Regional subset analyses showed the strongest correlation between PDH and lordotic correction achievable within the lumbar spine (n = 22, r = 0.77, P < .001), followed by ADH for lower thoracic spine (n = 29, r = 0.65, P < .001) and PDH for upper thoracic spine (n = 28, r = 0.61, P = .001). Postcorrection analysis of disc heights revealed that as lordotic correction increases, the PDH decreases, and the ADH expands. CONCLUSION PDH is a strong predictor of achievable lordotic correction following Schwab grade 2 osteotomies and compression of an intact disc space. In the lumbar spine, 50% of lordotic change is predictable using PDH alone. Further testing of our linear regression equation is planned for prospective clinical studies, and further testing of postcorrection disc space geometry is planned for future biomechanical and surgical technique studies.
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Lazaro, Bruno C. R., Kemal Yucesoy, Kasim Z. Yuksel, Izabela Kowalczyk, Doron Rabin, Marie Fink, and Neil Duggal. "Effect of arthroplasty design on cervical spine kinematics: analysis of the Bryan Disc, ProDisc-C, and Synergy Disc." Neurosurgical Focus 28, no. 6 (June 2010): E6. http://dx.doi.org/10.3171/2010.3.focus1058.
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Object Cervical total disc replacement has emerged as a surgical option to preserve motion and potentially avoid adjacent-segment disease after anterior cervical discectomy and fusion. Recently, much attention has been directed at the ability of a given device to maintain and/or restore normal segmental alignment. Nonphysiological disc and segmental angulation could result in increased stresses transmitted to the facet joints and posterior elements, conflicting with the essence of arthroplasty and potentially leading to adjacent-segment disease. The goal of this study was to contrast device alignment and segmental kinematics provided by 3 different cervical disc prostheses. Methods Sixty patients were retrospectively analyzed and divided into 3 groups receiving the Bryan, ProDisc-C, or Synergy disc. Only single-level arthroplasty cases were included in the study. Lateral dynamic radiographs of the cervical spine were analyzed using quantitative motion analysis software (Medical Metrics, Inc.) to analyze the kinematics at the index level both preoperatively and postoperatively. Several parameters were noted, including range of motion, disc angles, shell angles, anterior and posterior disc heights, translation, and center of rotation. Preoperative and postoperative data were compared using the Student t-test with a significance level of p < 0.05. Results Postoperatively, all 3 disc groups maintained adequate range of motion at the implanted level. With respect to the shell angles, the Synergy disc demonstrated the least variability, maintaining 6° lordotic configuration between the device endplates. In the Bryan disc group, significant shell kyphosis developed postoperatively (p < 0.0001). Both ProDisc-C and Synergy discs significantly increased anterior and posterior disc heights (p < 0.0001). The Bryan and Synergy discs maintained the natural center of rotation, whereas significant anterior shift occurred with ProDisc-C. Conclusions The goal for motion preservation at the implanted level was achieved using all 3 devices. The Synergy disc was unique in its ability to alter device angulation by 6°. The Bryan disc demonstrated device endplate kyphosis. Both the Synergy disc and ProDisc-C increased disc space height.
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Irshad, Faiza, Haroon Saeed, Sarfraz Ahmed, Amir Hussain Ashraf, Muhammad Nauman Akram, Muhammad Saad Abdullah, Mufassar Nishat, and Muhammad Afzal Khan. "Lumbar Vertebral Body and Disc Morphometry in Punjab." Pakistan Journal of Medical and Health Sciences 16, no. 3 (March 26, 2022): 646–48. http://dx.doi.org/10.53350/pjmhs22163646.
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Background and objective: Low back pain is common in the elderly due to adaptive changes to stress and osteoporosis of the lumbar spine. Skeletal geometry varies in different population groups. Objective of this study was to record reference values of morphometric data of lumbar spine in normal adult male and female subjects of Punjab. Study design: Cross-sectional population study Material and methods: Anterior and central height and concavity index for each vertebra were measured and calculated from radiographs. Anterior and posterior height and anteroposterior diameter were measured for each disc and wedge index was calculated. Results: All parameters were significantly larger in the males as compared to the females. Significant difference was found in the anterior height of the intervertebral discs at L1-2 to L4-5 while it was insignificant at L5-S1. Posterior height of discs was significantly larger in the male group at L1-2 to L3-4. Wedge index (WI) for discs was relatively larger in the female group. Conclusion: The study has provided some reference values of measurements of lumbar spine in adult male and female population of Punjab which may be valuable for better assessments of morphological changes by the clinician and for further research in this area. Keywords: Lumbar vertebrae, intervertebral disc, morphometry, concavity index, wedge index, lumbar spine
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Pisano, Alfred J., Donald R. Fredericks, Theodore Steelman, Cory Riccio, Melvin D. Helgeson, and Scott C. Wagner. "Lumbar disc height and vertebral Hounsfield units: association with interbody cage subsidence." Neurosurgical Focus 49, no. 2 (August 2020): E9. http://dx.doi.org/10.3171/2020.4.focus20286.
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OBJECTIVEPostoperative subsidence of transforaminal lumbar interbody fusion (TLIF) cages can result in loss of lordosis and foraminal height, and potential recurrence of nerve root impingement. The objectives of this study were to determine factors associated with TLIF cage subsidence. Specifically, the authors sought to determine if preoperative disc height compared to cage height could be used to predict TLIF interbody cage subsidence, and if decreased postoperative vertebral Hounsfield units (HUs) predisposed to cage subsidence.METHODSThe authors retrospectively reviewed all patients undergoing instrumented TLIF from two institutions between July 2004 and June 2014. The preoperative disc height was measured for the operative and adjacent-level disc on MRI. The difference between cage and disc heights was measured and compared between the subsidence and nonsubsidence groups. The average HUs of the L1 vertebral body were measured on CT scans.RESULTSEighty-nine patients were identified with complete imaging and follow-up information. Forty-five patients (50.6%) had evidence of interbody cage subsidence on follow-up CT. The average cage subsidence was 5.5 mm (range 2.2–10.8 mm). The average implant height was significantly higher in the subsidence group compared to the nonsubsidence group (12.6 vs 11.2 mm). Additionally, the difference between cage height and preoperative adjacent-level disc height was also significantly larger in the subsidence group (3.8 vs 1.2 mm). First lumbar vertebral body (L1) HUs were significantly higher in the nonsubsidence versus the subsidence group (167.8 vs 137.71 HUs, p = 0.002). Multivariate logistic regression analysis identified suprajacent disc height and L1 HUs to be independent predictors of interbody cage subsidence. Receiver operating characteristic curves identified a suprajacent to cage height difference > 1.3 mm to have a 93.3% sensitivity for cage subsidence.CONCLUSIONSThis study is the first of its kind to demonstrate the association between vertebral body HUs and suprajacent disc height with the development of interbody cage subsidence after TLIF. The authors found that patients with lower HUs in the L1 vertebral body were more likely to experience subsidence, regardless of surgical level. Additionally, the study demonstrated that interbody cage height > 1.3 mm above the height of the suprajacent level is an independent risk factor for cage subsidence, with 93.3% sensitivity. These findings suggest that these factors may be utilized to create a template preoperatively for intraoperative cage selection.
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González, Alejandro González Rebatú y., Ramón Ortega Padron,, Myriham Murguia Casas,, Rubén Vargas Burgos, and Rodrigo Bartolomé Vargas Lugo Salinas. "VERTEBROMETRY AND DISCOMETRY OF THE LUMBAR FUNCTIONAL SEGMENT (REBATÚ-MURGUÍA TECHNIQUE)." Coluna/Columna 16, no. 2 (April 2017): 112–15. http://dx.doi.org/10.1590/s1808-185120171602172305.
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ABSTRACT Surgical treatment of intervertebral disc degeneration aims to restore the height of the disc space and the release of involved neurological structures. Like any surgical treatment in orthopedics, the success or failure of the lumbar procedure involves the possibility of performing an adequate planning of each particular event. In the case of lumbar stabilization surgery with interbody fusion, it is essential to know the ideal height of the disc space for the fusion to be successful. Objective: To demonstrate that the ideal height of the disc space corresponds approximately to one third of the height of the vertebral body. Methods: X-ray images were taken in AP and lateral views of hospital residents to measure L4-L5 vertebral bodies as well as the disc space. The rule of three was used to check the height of the disc and vertebral bodies. Results: It was verified that the disc space corresponds to 31% of the size of the vertebral body, taking 0.31 as the constant. Conclusions: The size of the disc corresponds to one third of the vertebral body, taking 0.31 as the constant. The multiplication of the constant by the height of the vertebral body results in the exact height of the disc. Thus, in the presence of degeneration of the intervertebral disc, it is possible to know the size of the disc and, therefore, the size of the interbody cage.
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MIKUCKYTĖ, Sandra, and Vytautas OSTAŠEVIČIUS. "Experimental Investigation of an Influence of Coupled Compressive Loading on Porcine Spine Specimens." Mechanics 27, no. 1 (February 24, 2021): 40–44. http://dx.doi.org/10.5755/j02.mech.26903.
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The human spine shortens approximately by 1% of its height during the daily activities and returns to its primary height during the night rest. Cyclic loading is important in order to ensure diffusion and convention of the nutrients and metabolites within the intervertebral discs. On the other hand, cyclic loading could lead to the damage of the intervertebral discs and the vertebra bodies if the magnitude and frequency of the loads applied to the spine exceed the allowable limits. As most of the in vitro studies that investigate the influence of cyclic loading deal with functional spinal units consisting of single intervertebral disc the purpose of this study is to investigate an influence of cyclic compression and flexion on the structural integrity and geometrical parameters of the spinal specimens consisting of more than one intervertebral disc. Two specimens consisting of four adjacent vertebrae and three intervertebral discs were scanned by using computed tomography then loaded with combined cyclic compression and flexion and then scanned for the second time in order to capture the current condition of the specimens. Obtained images were used to evaluate the changes of structural integrity and geometrical parameters of the discs. A significant decrease of the specimen height was observed during loading, mainly due to the loss of the fluid content within intervertebral discs. In total, the difference of the height of the two specimens immediately after the loading was 1.577 mm. No obvious damage to the specimens was observed when comparing images before and after the loading. A statistically significant differences between the height of the intervertebral discs before and after loading in both the first specimen (p = 0.0224) and the second specimen (p = 0.0155) were calculated with the lowest disc of both specimens decreasing the most and obviously losing the highest water content. The cross-sectional area of the lowest disc in both specimens also decreased the most. This once again confirms that lower part of the spine such as intervertebral discs L4-L5 and L5-S1 are the least prone to the injuries and degeneration due to disturbed nutrition and loss of water content.
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Mattar, Thiago, Alexandre Barros Costa, Paulo Roberto Appolonio, André Evaristo Marcondes Cesar, and Luciano Miller Reis Rodrigues. "Thickness of the ligamentum flavum of the spine and its relationship with disc degeneration." Coluna/Columna 13, no. 2 (2014): 112–15. http://dx.doi.org/10.1590/s1808-18512014130200321.
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Objective: This study investigates whether the thickening of the ligamentum flavum (LF) is correlated with disc degeneration. Methods: This retrospective study was conducted with 98 patients with chronic low back pain treated in a spinal surgery service between January 2012 and January 2013. All patients underwent magnetic resonance imaging (MRI) and the images were evaluated by a spinal surgeon to measure the thickness of the LF and evaluate the degree of disc degeneration by the Pfirrmann grading system, according to the spinal levels (L3 -L4, L4-L5, L5-S1). An association was sought between LF hypertrophy and disc degeneration, age, sex and disc height. Results: The mean age of the patients was 53.6 years, and the majority were women (59.2%). The thickness of the LF and disc height varied according to the spinal level, the greatest LF thickness being found between L4-L5, and the greatest disc height at L5-S1. Women had statistically thicker ligaments in L3/L4 than men. The degree of disc degeneration was inversely correlated with the height at all the levels evaluated, i.e., the greater the degree of degeneration, the lower the disc height. Conclusions: The thickening of LF is not related to disc height or degree of disc degeneration. Therefore, there is no deformation of the LF within the spinal canal secondary to disc degeneration.
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White, Tammy L., and Terry R. Malone. "Effects of Running on Intervertebral Disc Height." Journal of Orthopaedic & Sports Physical Therapy 12, no. 4 (October 1990): 139–46. http://dx.doi.org/10.2519/jospt.1990.12.4.139.
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Inoue, H., K. Ohmori, K. Miyasaka, and H. Hosoe. "Radiographic evaluation of the lumbosacral disc height." Skeletal Radiology 28, no. 11 (November 12, 1999): 638–43. http://dx.doi.org/10.1007/s002560050566.
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&NA;. "No Change in Disc Height with Age." Back Letter 2, no. 4 (February 1988): 3. http://dx.doi.org/10.1097/00130561-198802000-00003.
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Stabler, John. "The measured height of the lumbosacral disc." British Journal of Radiology 61, no. 732 (December 1988): 1191. http://dx.doi.org/10.1259/0007-1285-61-732-1191-a.
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Nicholson, A. A. "The measured height of the lumbosacral disc." British Journal of Radiology 61, no. 732 (December 1988): 1191. http://dx.doi.org/10.1259/0007-1285-61-732-1191-b.
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Falkinstein, Yuri, Tatiana Smith, Ken Hsu, and James Zucherman. "P187. Correlation Between the Preoperative Disc Height, the Change in Disc Height, the Size of the Implant, and Outcomes in Total Disc Replacement." Spine Journal 8, no. 5 (September 2008): 190S. http://dx.doi.org/10.1016/j.spinee.2008.06.829.
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Oehme, David, Peter Ghosh, Tony Goldschlager, Silviu Itescu, Susan Shimon, Jiehua Wu, Courtney McDonald, John M. Troupis, Jeffrey V. Rosenfeld, and Graham Jenkin. "Reconstitution of degenerated ovine lumbar discs by STRO-3–positive allogeneic mesenchymal precursor cells combined with pentosan polysulfate." Journal of Neurosurgery: Spine 24, no. 5 (May 2016): 715–26. http://dx.doi.org/10.3171/2015.8.spine141097.
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OBJECTIVE Disc degeneration and associated low-back pain are major causes of suffering and disability. The authors examined the potential of mesenchymal precursor cells (MPCs), when formulated with pentosan polysulfate (PPS), to ameliorate disc degeneration in an ovine model. METHODS Twenty-four sheep had annular incisions made at L2–3, L3–4, and L4–5 to induce degeneration. Twelve weeks after injury, the nucleus pulposus of a degenerated disc in each animal was injected with ProFreeze and PPS formulated with either a low dose (0.1 million MPCs) or a high dose (0.5 million MPCs) of cells. The 2 adjacent injured discs in each spine were either injected with PPS and ProFreeze (PPS control) or not injected (nil-injected control). The adjacent noninjured L1–2 and L5–6 discs served as noninjured control discs. Disc height indices (DHIs) were obtained at baseline, before injection, and at planned death. After necropsy, 24 weeks after injection, the spines were subjected to MRI and morphological, histological, and biochemical analyses. RESULTS Twelve weeks after the annular injury, all the injured discs exhibited a significant reduction in mean DHI (low-dose group 17.19%; high-dose group 18.01% [p < 0.01]). Twenty-four weeks after injections, the discs injected with the low-dose MPC+PPS formulation recovered disc height, and their mean DHI was significantly greater than the DHI of PPS- and nil-injected discs (p < 0.001). Although the mean Pfirrmann MRI disc degeneration score for the low-dose MPC+PPS–injected discs was lower than that for the nil- and PPS-injected discs, the differences were not significant. The disc morphology scores for the nil- and PPS-injected discs were significantly higher than the normal control disc scores (p < 0.005), whereas the low-dose MPC+PPS–injected disc scores were not significantly different from those of the normal controls. The mean glycosaminoglycan content of the nuclei pulposus of the low-dose MPC+PPS–injected discs was significantly higher than that of the PPS-injected controls (p < 0.05) but was not significantly different from the normal control disc glycosaminoglycan levels. Histopathology degeneration frequency scores for the low-dose MPC+PPS–injected discs were lower than those for the PPS- and Nil-injected discs. The corresponding high-dose MPC+PPS–injected discs failed to show significant improvements in any outcome measure relative to the controls. CONCLUSIONS Intradiscal injections of a formulation composed of 0.1 million MPCs combined with PPS resulted in positive effects in reducing the progression of disc degeneration in an ovine model, as assessed by improvements in DHI and morphological, biochemical, and histopathological scores.
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Priymak, Maxim A., Alexei I. Gaivoronsky, Ivan V. Gaivoronsky, Gennadii I. Nichiporuk, Maria G. Gaivoronskaya, and Inga A. Goriacheva. "Lifetime morphological characteristics of the L<sub>IV</sub>-L<sub>V</sub> intervertebral disc in young and middle-aged adults." Bulletin of the Russian Military Medical Academy 24, no. 4 (January 4, 2023): 689–96. http://dx.doi.org/10.17816/brmma110717.
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Morphoscopic and morphometric characteristics of the LIVLV intervertebral disc were assessed according to magnetic resonance images of the lumbar spine of 90 patients (66 men, 24 women). The morphometric parameters of the LIVLV intervertebral disc and nucleus pulposus were compared between young (1844 years old) and middle-aged (4560 years old) adults and in groups determined by sex and body type. In addition, morphoscopic characteristics, namely, the shape of the intervertebral disc and nucleus pulposus in the axial plane, were evaluated. Results. In normal intervertebral disc, LIVLV on the axial section most often presents in a kidney-shaped (51%), elliptical (45%), and round (4%) form. The LIVLV nucleus pulposus normally has an oval (50%), kidney (45%), and less often a lemniscate (5%) shape. The shape and individual morphometric parameters of the intervertebral disc and nucleus pulposus of the LIVLV segment have significant sex differences. Thus, the most lateral height of the intervertebral disc on the right and left, anteroposterior size and area of the intervertebral disc, and anteroposterior size, width, and area of the nucleus pulposus are significantly larger in men than in women. When assessing the influence of body type on intervertebral disc structural features, no significant differences in its shape were found between asthenics, normo- and hypersthenics, while individual dimensions (intervertebral disc height in the center and its dorsal height) were significantly larger in hypersthenics. The kidney-shaped form of the nucleus pulposus was significantly more common in asthenics and the oval form in hypersthenics, whereas the morphometric parameters of the nucleus pulposus did not significantly differ between extreme body types. Statistically significant differences in the shape of the nucleus pulposus were found between age groups. The results of the analysis of morphometric characteristics revealed the intervertebral disc height tended to decrease in middle-aged people compared with young people. The results can be used in planning spine surgery and designing artificial intervertebral discs.
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Calleja-Agius, J., Y. Muscat-Baron, and M. P. Brincat. "Estrogens and the intervertebral disc." Menopause International 15, no. 3 (August 31, 2009): 127–30. http://dx.doi.org/10.1258/mi.2009.009016.
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Intervertebral discs are an integral part of the vertebral column. It has been shown that menopause has a negative effect on bone and on intervertebral discs. Estrogen has a beneficial effect of preserving the health of collagen-containing tissues, including the intervertebral disc. The intervertebral disc allows for mobility of the spine, and maintains a uniform stress distribution of the area of the vertebral endplates. Also, the disc influences spinal height. The disc tissue is adapted for this biomechanical function. The function of the spine is impaired if there is a loss of disc tissue. Narrowing of the disc space due to degeneration of intervertebral discs is associated with a significantly increased risk of vertebral fractures. Estrogen should be seen as the first-choice therapy for bones and other collagen-rich tissues, such as intervertebral discs, because it maintains homeostasis of the bone-remodelling unit. Unlike bisphosphonates, estrogen is unique in its ability to regenerate bone collagen after its disintegration, apart from suppressing osteoclastic activity. Besides, there is insufficient data on deterioration in bone qualities and micro-cracks in patients on long-term bisphosphonates.
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Oehme, David, Peter Ghosh, Susan Shimmon, Jiehua Wu, Courtney McDonald, John M. Troupis, Tony Goldschlager, Jeffrey V. Rosenfeld, and Graham Jenkin. "Mesenchymal progenitor cells combined with pentosan polysulfate mediating disc regeneration at the time of microdiscectomy: a preliminary study in an ovine model." Journal of Neurosurgery: Spine 20, no. 6 (June 2014): 657–69. http://dx.doi.org/10.3171/2014.2.spine13760.
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Object Following microdiscectomy, discs generally fail to undergo spontaneous regeneration and patients may experience chronic low-back pain and recurrent disc prolapse. In published studies, formulations of mesenchymal progenitor cells combined with pentosan polysulfate (MPCs+PPS) have been shown to regenerate disc tissue in animal models, suggesting that this approach may provide a useful adjunct to microdiscectomy. The goal of this preclinical laboratory study was to determine if the transplantation of MPCs+PPS, embedded in a gelatin/fibrin scaffold (SCAF), and transplanted into a defect created by microdiscectomy, could promote disc regeneration. Methods A standardized microdiscectomy procedure was performed in 18 ovine lumbar discs. The subsequent disc defects were randomized to receive either no treatment (NIL), SCAF only, or the MPC+PPS formulation added to SCAF (MPCs+PPS+SCAF). Necropsies were undertaken 6 months postoperatively and the spines analyzed radiologically (radiography and MRI), biochemically, and histologically. Results No adverse events occurred throughout the duration of the study. The MPC+PPS+SCAF group had significantly less reduction in disc height compared with SCAF-only and NIL groups (p < 0.05 and p < 0.01, respectively). Magnetic resonance imaging Pfirrmann scores in the MPC+PPS+SCAF group were significantly lower than those in the SCAF group (p = 0.0213). The chaotropic solvent extractability of proteoglycans from the nucleus pulposus of MPC+PPS+SCAF-treated discs was significantly higher than that from the SCAF-only discs (p = 0.0312), and using gel exclusion chromatography, extracts from MPC+PPS+SCAF-treated discs also contained a higher percentage of proteoglycan aggregates than the extracts from both other groups. Analysis of the histological sections showed that 66% (p > 0.05) of the MPC+PPS+SCAF-treated discs exhibited less degeneration than the NIL or SCAF discs. Conclusions These findings demonstrate the capacity of MPCs in combination with PPS, when embedded in a gelatin sponge and sealed with fibrin glue in a microdiscectomy defect, to restore disc height, disc morphology, and nucleus pulposus proteoglycan content.
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Wu, Pang Hung, Hyeun Sung Kim, Yeon Jin Lee, Dae Hwan Kim, Jun Hyung Lee, Jun Bok Jeon, Harshavardhan Dilip Raorane, and Il-Tae Jang. "Uniportal Full Endoscopic Posterolateral Transforaminal Lumbar Interbody Fusion with Endoscopic Disc Drilling Preparation Technique for Symptomatic Foraminal Stenosis Secondary to Severe Collapsed Disc Space: A Clinical and Computer Tomographic Study with Technical Note." Brain Sciences 10, no. 6 (June 15, 2020): 373. http://dx.doi.org/10.3390/brainsci10060373.
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Background: Severe collapsed disc secondary to degenerative spinal conditions leads to significant foraminal stenosis. We hypothesized that uniportal posterolateral transforaminal lumbar interbody fusion with endoscopic disc drilling technique could be safely applied to the collapsed disc space to improve patients’ pain score, restore disc height, and correct the segmental angular parameters. Methods: We included patients who met the indication criteria for lumbar fusion and underwent uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion with pre-operative Computer Tomography mid disc height of less than or equal to 5 mm and MRI of Grade 3 Foraminal Stenosis. Visual analogue scale and computer tomography pre-operative and post-operative sagittal disc height in the anterior, middle and posterior part of the disc; sagittal focal segmental angle; mid coronal disc height and coronal wedge angles were evaluated. Results: 30 levels of Endo-TLIF were included, with a mean follow up of 12 months. The mean improvement in decreasing pain score was 2.5 ± 1.1, 3.2 ± 0.9 and 4.3 ± 1.0 at 1 week post operation, 3 months post operation and at final follow up, respectively, p < 0.05. There was significant increase in mid sagittal computer tomographic anterior, middle and posterior disc height of 6.99 ± 2.30, 6.28 ± 1.44, 5.12 ± 1.79 mm respectively, p < 0.05. CT mid coronal disc height showed an increase of 7.13 ± 1.90 mm, p < 0.05. There was a significant improvement in the CT coronal wedge angle of 2.35 ± 4.73 and the CT segmental focal sagittal angle of 1.98 ± 4.69, p < 0.05. Conclusion: Application of Uniportal Endoscopic Posterolateral Lumbar Interbody Fusion in patients with severe foraminal stenosis secondary to severe collapsed disc space significantly relieved patients’ pain and restored disc height without early subsidence or exiting nerve root dysesthesia in our cohort of patients.
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Khadgi, Kedar, and Tanoj Bahadur Singh. "Most Common MRI finding in Lumbosacral Degenerative changes in Nepal Police." Nepal Medical Journal 4, no. 1 (November 4, 2021): 7–14. http://dx.doi.org/10.37080/nmj.154.
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Introduction: Low back pain (LBP) is a common problem that affects about two-thirds of adults sometimes in their life. Magnetic Resonance Imaging (MRI) with excellent tissue contrast is a better modality for assessing it. We aimed to assess the common findings overall, gender-wise and age-wise in lumbosacral degenerative changes in Nepal police personnel. Methods: The 54 Nepalese police with disc degeneration changes in the MRI report were included . The following MRI findings were evaluated: decrease disc height, disc desiccation change, diffuse disc bulge, asymmetrical disc bulge, disc protrusion, disc extrusion, annular tear, central spinal canal stenosis, foraminal stenosis, spinal nerve compromise, lumbar lordosis preserved or not, osteophyte and modic changes. Results: Mostly involved lumbosacral discs were L4-L5 and L5-S1 and the least involved lumbosacral disc was L1-L2. Disc desiccation changes were the most common finding observed. Disc desiccation changes, decreased disc height, lateral recess stenosis, foraminal stenosis was common in L5-S1. Diffuse disc bulge, asymmetric disc bulge, disc protrusion, annular tear, central spinal canal stenosis were common in L4-L5. Modic type II change was the commonest endplate change observed.. Lateral recess stenosis and foraminal stenosis showed an increasing trend with increment in age group. The most common finding in both gender was disc desiccation changes and diffuse disc bulge. However, disc protrusion, disc extrusion, and annular tear were more common in males and asymmetrical disc bulge in females. Conclusion: This study shows L4-L5 and L5-S1 is the most common intervertebral disc involved in degeneration in Nepal police. Disc desiccation change and diffuse disc bulge are the most frequent finding irrespective of age and gender. Degenerative changes have an increasing trend with increasing age. Disc herniation is more common in male police individuals than female police individuals of Nepal.
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Marshman, Laurence A. G., Andrew V. Metcalfe, Manoj Krishna, and Tai Friesem. "Are high-intensity zones and Modic changes mutually exclusive in symptomatic lumbar degenerative discs?" Journal of Neurosurgery: Spine 12, no. 4 (April 2010): 351–56. http://dx.doi.org/10.3171/2009.10.spine08856.
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Object Modic changes (MCs) and high-intensity zones (HIZs) potentially serve as variably sensitive markers for discogenic chronic low-back pain (CLBP). No study has hitherto assessed the phenomenon of MC-HIZ coexistence at a single level, and the goal in this study was to assess the nature and frequency of this phenomenon. Methods One hundred twenty consecutive patients with discogenic CLBP in whom lumbar MR imaging studies had demonstrated an HIZ, an MC, or both were included. Results This cohort (120 consecutive patients with 193 degenerative discs) had discogenic CLBP in at least 1 lumbar level associated with either an HIZ (77 discs), an MC (67 discs), or both (16 patients); there were 55 coexistent non-HIZ/non-MC degenerative discs. Painful MC-HIZ coexistence at 1 level occurred in 6 patients (5 of whom were female). If HIZs and MCs were random, independent entities, then MC-HIZ coexistence at 1 level would have been expected in 67 × 77/193 (that is, 27) discs. The observed frequency was therefore significantly lower (χ2 = 41, p < 0.001). There were no significant demographic differences between groups. The HIZ disc height (8 ± 0.2 mm) was significantly greater than the MC (6.6 ± 0.2 mm) or MC-HIZ (6.7 ± 0.2 mm) disc heights (p < 0.001). Conclusions In patients with discogenic CLBP associated with HIZ or MC lesions, MC-HIZ coexistence at 1 level was significantly rarer than expected even by chance; thus, despite both being manifestations of a seemingly common degenerative process, HIZ and MC more closely represent “either/or” phenomena. Because HIZ disc height was significantly greater, HIZs may develop earlier in the disc degenerative ontogeny. If any degenerative disc may only display an HIZ first, yet may ultimately display an MC instead, then HIZs must invariably regress as MCs supervene (or even vice versa). The MC-HIZ coexistence would therefore represent either a rare stable state (possibly more common in females) or a transitory state, as one lesion gradually replaces the other. Longitudinal studies would confirm or refute these hypotheses, although significantly larger sample sizes would be required.
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Luo, T. David, Alejandro Marquez-Lara, Zachary K. Zabarsky, Jeremy B. Vines, Katie C. Mowry, Alexander H. Jinnah, Xue Ma, et al. "A percutaneous, minimally invasive annulus fibrosus needle puncture model of intervertebral disc degeneration in rabbits." Journal of Orthopaedic Surgery 26, no. 3 (August 16, 2018): 230949901879271. http://dx.doi.org/10.1177/2309499018792715.
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Purpose: Various animal models have been proposed to mimic the pathophysiologic process of intervertebral disc degeneration, a leading cause of back pain. The purpose of this study is to describe a minimally invasive technique via percutaneous needle puncture of the annulus fibrosus in New Zealand white rabbits. Methods: Under fluoroscopic guidance, an 18-gauge spinal needle was inserted 2 cm lateral to the midline spinous process. The needle was slowly advanced at approximately 45° angle until it was adjacent to the L5/L6 disc space. Lateral and anteroposterior views were used to verify correct needle position before advancing into the nucleus pulposus. The rabbits underwent weekly X-rays for 4 weeks to assess disc height index. MRI T2 relaxation was evaluated at week four to assess morphological changes. Discs were histologically graded on a 12-point scale to assess degeneration and compared to discs obtained from uninjured rabbits. Results: There were no complications associated with the percutaneous needle puncture procedure. All animals survived the duration of the experiment. Four weeks after injury, the disc height had progressively narrowed to approximately 50% of baseline. MRI assessment at the 4-week time point demonstrated a mean T2 relaxation time at the L5/L6 level that was 20.9% of the T2 relaxation time at the uninjured L4/L5 disc level ( p < 0.001). Histological analysis demonstrated lamellar disorganization of the annulus and decreased cellularity and proteoglycan content within the injured nucleus compared to uninjured control discs. Conclusion: The present study demonstrated a reliable technique of inducing an annular tear via a percutaneous needle puncture. Compared to open surgical approaches, the percutaneous model produces similar progressive disc degeneration while minimizing harm to the animal subjects. Clinical Relevance: The present study establishes a technique for the introduction of novel therapeutic agents to treat disc degeneration that may translate to future clinical trials.
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Holguin, Nilsson, Rhiannon Aguilar, Robin A. Harland, Bradley A. Bomar, and Matthew J. Silva. "The aging mouse partially models the aging human spine: lumbar and coccygeal disc height, composition, mechanical properties, and Wnt signaling in young and old mice." Journal of Applied Physiology 116, no. 12 (June 15, 2014): 1551–60. http://dx.doi.org/10.1152/japplphysiol.01322.2013.
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Murine lumbar and coccygeal (tail) regions of spines are commonly used to study cellular signaling of age-related disc diseases, but the tissue-level changes of aging intervertebral discs and vertebrae of each spinal region remain unclear. Furthermore, the impact of aging lumbar and coccygeal discs on Wnt/β-catenin signaling, which is putatively involved in the catabolism of intervertebral discs, is also unclear. We compared disc/vertebrae morphology and mechanics and biochemical composition of intervertebral discs from lumbar and coccygeal regions between young (4–5 mo) and old (20–22 mo) female C57BL/6 mice. Center intervertebral disc height from both regions was greater in old discs than young discs. Compared with young, old lumbar discs had a lower early viscous coefficient (a measure of stiffness) by 40%, while conversely old coccygeal discs were stiffer by 53%. Biochemically, old mice had double the collagen content in lumbar and coccygeal discs of young discs, greater glycosaminoglycan in lumbar discs by 37%, but less glycosaminoglycan in coccygeal discs by 32%. Next, we compared Wnt activity of lumbar and coccygeal discs of 4- to 5-mo and 12- to 14-mo TOPGAL mice. Despite the disc-specific changes, aging decreased Wnt signaling in the nucleus pulposus from both spinal regions by ≥64%. Compared with young, trabecular bone volume/tissue volume and ultimate force were less in old lumbar vertebrae, but greater in old coccygeal vertebrae. Thus intervertebral discs and vertebrae age in a spinal region-dependent manner, but these differential age-related changes may be uncoupled from Wnt signaling. Overall, lumbar and coccygeal regions are not interchangeable in modeling human aging.
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Subach, Brian R., Anne G. Copay, Marcus M. Martin, and Thomas C. Schuler. "Anterior Lumbar Interbody Implants: Importance of the Interdevice Distance." Advances in Orthopedics 2011 (2011): 1–5. http://dx.doi.org/10.4061/2011/176497.
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Object. The implantation of interbody fusion cages allows for the restoration of disc height and the enlargement of the neuroforaminal space. The purpose of this study was to compare the extent of subsidence occurring after conventional cage placement compared to a novel wider cage placement technique.Methods. This study is a retrospective evaluation of radiographs of patients who underwent stand-alone single level anterior lumbar interbody fusion with lordotic titanium cages and rhBMP-2. Fifty-three patients were evaluated: 39 patients had wide cage placement (6 mm interdevice distance) and 14 had narrow cage placement (2 mm interdevice distance). Anterior and posterior intervertebral disc space heights were measured post-operatively and at follow-up imaging.Results. The decrease in anterior intervertebral disc space height was 2.05 mm versus 3.92 mm () and 1.08 mm versus 3.06 mm in posterior disc space height for the wide cage placement and the narrow cage placement respectively. The proportion of patients with subsidence greater than 2 mm was 41.0% in the wide cage patients and 85.7% for the narrow cage patients ().Conclusions. The wider cage placement significantly reduced the amount of subsidence while allowing for a greater exposed surface area for interbody fusion.
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van der Maaten-Theunissen, Marieke, and Olivier Bouriaud. "Climate–growth relationships at different stem heights in silver fir and Norway spruce." Canadian Journal of Forest Research 42, no. 5 (May 2012): 958–69. http://dx.doi.org/10.1139/x2012-046.
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We investigated the effect of climate on variations in annual ring-area increment along the stem of dominant silver fir ( Abies alba Mill.) and Norway spruce ( Picea abies (L.) Karst.) trees in the Black Forest, southwestern Germany, to test the hypothesis that growth allocation changes as a result of climate fluctuations. Stem discs were taken at three different stem heights: 1.30, 11.50, and 16.70 m. For each site and stem height, average annual ring-area increment chronologies were computed. In addition, we calculated ratios between ring-area increment of the upper stem discs and the disc at breast height to compare growth variations along the stem. Pearson correlation coefficients revealed a highly similar growth pattern at different stem heights, where the two upper discs were most similar. Bootstrapped correlation coefficients between the ring-area increment chronologies, ratios, and monthly temperature, precipitation, and self-calibrated Palmer drought sensitivity index data were calculated to analyze differences in climate response. High temperatures in early summer were found to reduce growth of high-altitude fir in the upper stem parts, whereas high temperatures in summer limit growth of high-altitude fir and spruce, especially at breast height. For low-altitude trees, high temperatures as well as low precipitation amounts during summer were found to reduce growth at all stem heights, but more strongly at breast height. Growth at breast height seems to be biased, as it over- or underestimates annual ring-area increments along the stem (and thereby volume increment), particularly during warm and dry climate conditions.
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Rohlmann, A., T. Zander, B. Bock, and G. Bergmann. "Effect of position and height of a mobile core type artificial disc on the biomechanical behaviour of the lumbar spine." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 222, no. 2 (February 1, 2008): 229–39. http://dx.doi.org/10.1243/09544119jeim241.
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The extent of natural disc removal and the implant position and height of an artificial disc with a mobile core were studied for their effects on intersegmental rotation, intradiscal pressure, and facet joint force. A validated finite element model of the lumbar spine was used. The model was loaded with the upper body weight, a follower load, and muscle forces to simulate standing, flexion, extension, lateral bending, and axial rotation. The implant position was varied up to 2 mm in an anterior and posterior direction and up to 3 mm in a lateral direction. Three different implant heights were simulated. The effect of removing the lateral parts of the annulus was also studied. The implant position and height markedly affect intersegmental rotation and facet joint forces but have hardly any influence on intradiscal pressure in the adjacent discs. Removing the lateral parts of the annulus increases intersegmental rotation and facet joint force mainly for lateral bending and axial rotation. The calculated translation of the mobile implant core is about 1 mm at most, and thus its effect is often overestimated. Great care should be taken to choose the optimal implant height and to insert the implant in the best position for each individual patient.
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Zheng, Yuchen, Tao Lan, Xiaosheng Chen, Zhihao Hus, and Rui Zhang. "Correlation between Pain Scores and Disc Height Changes after Discectomy in Patients with Lumbar Disc Herniation: A Systematic Review and Meta-Analysis." Computational Intelligence and Neuroscience 2022 (August 5, 2022): 1–9. http://dx.doi.org/10.1155/2022/2580004.
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Background. Surgery can reduce and improve lumbar disc herniation, but some patients still have pain after surgery, and the relationship between lumbar disc height and pain after surgery is still unclear. Objective. The main objective is to investigate the relationship between lumbar disc height and postoperative pain. Methods. We searched Pubmed, Web of Science, the Cochrane library, and Embase online for cohort studies or RCT studies on discectomy and assessed the quality of the included articles using the Newcastle-Ottawa Scale (NOS scale), with disc height (DH) and postoperative back pain as the main clinical outcome indicators, and the correlation coefficient between DH and back pain as the statistic to assess the pooled effect size. Results. 10 kinds of literature were included in this study for quantitative analysis. A total of 589 patients participated in the study. The follow-up time was between 1 and 2.3 years. Meta-analysis showed that after surgery, the relief of back pain was statistically significant (MD = −2.57, 95% CI (−3.10,−2.04), Z = −9.570, P < 0.0001 ), the reduction of disc height was statistically significant (MD = −0.82, 95% CI (−1.11, −0.52), Z = −5.477, P < 0.0001 ), the combined value of correlation coefficient Fisher’s Z value was 0.33, 95% CI (0.25,0.42), with statistical significance ( P < 0.00001 ), suggesting that the degree of back pain after surgery showed a moderate positive correlation with disc height in the short term. Discussion. After discectomy, the degree of pain is relieved, the disc height is reduced, and low back pain in the short term and disc height showed a moderate positive correlation, but the long-term correlation remains to be studied in depth.
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Kowalczyk, Izabela, Bruno C. R. Lazaro, Marie Fink, Doron Rabin, and Neil Duggal. "Analysis of in vivo kinematics of 3 different cervical devices: Bryan disc, ProDisc-C, and Prestige LP disc." Journal of Neurosurgery: Spine 15, no. 6 (December 2011): 630–35. http://dx.doi.org/10.3171/2011.8.spine11273.
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Object Cervical arthroplasty has emerged as a means of preventing adjacent segment disease by preserving motion, restoring sagittal balance, and mimicking natural spinal kinematics. The purpose of this retrospective in vivo study was to characterize the impact of arthroplasty on sagittal balance and segmental kinematics of the cervical spine. Methods Sixty patients receiving the Bryan disc, ProDisc-C, or Prestige LP disc were retrospectively analyzed. Only single-level arthroplasty cases were included in this study. Lateral dynamic radiographs of the cervical spine were evaluated using quantitative measurement analysis software to determine the kinematics at the index level both preoperatively and 1 year postoperatively. Collected parameters included range of motion (ROM), disc angles, shell angles, anterior and posterior disc heights (ADHs/PDHs), translation, and center of rotation (COR). Preoperative and postoperative data were compared using the Student t-test, with p < 0.05 indicating significance. Results The Bryan and Prestige LP discs preserved motion, whereas the ProDisc-C increased segmental ROM from extension to flexion. Following surgery, the Bryan disc exhibited significant shell angle kyphosis, while ProDisc-C and Prestige LP retained lordosis. Both ADHs and PDHs decreased following insertion of the Bryan disc. In contrast, the ProDisc-C increased the ADHs and PDHs by 80% and 52%, respectively, and the Prestige LP disc increased the ADHs and PDHs by 20%. Only the ProDisc-C demonstrated significant translation of 0.7 mm. The ProDisc-C shifted the COR x by 0.9 mm anteriorly, while the Prestige LP disc demonstrated a significant superior shift of 2.2 mm in COR y. Conclusions All discs adequately maintained ROM at the surgical level. The greatest difference among the 3 devices was in the disc height and index angle measurements.
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Walker, Corey T., David S. Xu, Tyler S. Cole, Lea M. Alhilali, Jakub Godzik, Santiago Angel Estrada, Juan Pedro Giraldo, et al. "Predictors of indirect neural decompression in minimally invasive transpsoas lateral lumbar interbody fusion." Journal of Neurosurgery: Spine 35, no. 1 (July 2021): 80–90. http://dx.doi.org/10.3171/2020.8.spine20676.
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OBJECTIVE An advantage of lateral lumbar interbody fusion (LLIF) surgery is the indirect decompression of the neural elements that occurs because of the resulting disc height restoration, spinal realignment, and ligamentotaxis. The degree to which indirect decompression occurs varies; no method exists for effectively predicting which patients will respond. In this study, the authors identify preoperative predictive factors of indirect decompression of the central canal. METHODS The authors performed a retrospective evaluation of prospectively collected consecutive patients at a single institution who were treated with LLIF without direct decompression. Preoperative and postoperative MRI was used to grade central canal stenosis, and 3D volumetric reconstructions were used to measure changes in the central canal area (CCA). Multivariate regression was used to identify predictive variables correlated with radiographic increases in the CCA and clinically successful improvement in visual analog scale (VAS) leg pain scores. RESULTS One hundred seven levels were treated in 73 patients (mean age 68 years). The CCA increased 54% from a mean of 0.96 cm2 to a mean of 1.49 cm2 (p < 0.001). Increases in anterior disc height (74%), posterior disc height (81%), right (25%) and left (22%) foraminal heights, and right (12%) and left (15%) foraminal widths, and reduction of spondylolisthesis (67%) (all p < 0.001) were noted. Multivariate evaluation of predictive variables identified that preoperative spondylolisthesis (p < 0.001), reduced posterior disc height (p = 0.004), and lower body mass index (p = 0.042) were independently associated with radiographic increase in the CCA. Thirty-two patients were treated at a single level and had moderate or severe central stenosis preoperatively. Significant improvements in Oswestry Disability Index and VAS back and leg pain scores were seen in these patients (all p < 0.05). Twenty-five (78%) patients achieved the minimum clinically important difference in VAS leg pain scores, with only 2 (6%) patients requiring direct decompression postoperatively due to persistent symptoms and stenosis. Only increased anterior disc height was predictive of clinical failure to achieve the minimum clinically important difference. CONCLUSIONS LLIF successfully achieves indirect decompression of the CCA, even in patients with substantial central stenosis. Low body mass index, preoperative spondylolisthesis, and disc height collapse appear to be most predictive of successful indirect decompression. Patients with preserved disc height but severe preoperative stenosis are at higher risk of failure to improve clinically.
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Lee, June-Kyu, Jae Sung Ahn, Chang-Hwa Hong, and Jung Bum Lee. "The Changes of Disc Height and Degeneration in Patients with Lumbar Disc Herniation." Journal of Korean Society of Spine Surgery 12, no. 1 (2005): 58. http://dx.doi.org/10.4184/jkss.2005.12.1.58.
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Kim, Kyoung-Tae, Seung-Won Park, and Young-Baeg Kim. "Disc Height and Segmental Motion as Risk Factors for Recurrent Lumbar Disc Herniation." Spine 34, no. 24 (November 2009): 2674–78. http://dx.doi.org/10.1097/brs.0b013e3181b4aaac.
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Lu, Michael Y., William C. Hutton, and Vasanti M. Gharpuray. "Can Variations in Intervertebral Disc Height Affect the Mechanical Function of the Disc?" Spine 21, no. 19 (October 1996): 2208–16. http://dx.doi.org/10.1097/00007632-199610010-00006.
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Schwarze, Martin, and Marcus Schiltenwolf. "BK 2108 – The Calculation of the Normalized Relative Lumbar Disc Height." Zeitschrift für Orthopädie und Unfallchirurgie 157, no. 04 (October 15, 2018): 378–85. http://dx.doi.org/10.1055/a-0732-6077.
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AbstractThe assessment of the medical conditions (liability-compliant causality) of the BK 2108 is a frequent assessment, which poses a challenge to the medical expert in orthopaedics and trauma surgery. In assessing the load-consistent damage pattern, defined changes in the intervertebral discs as well as the adjacent vertebral bodies must be comprehended in a standardised manner. Of several technical measuring methods, three practicable methods are discussed and their application explained. Thus, methods are provided which allow the medical expert to calculate the normalised relative disc height. In this way, the specifications of the consensus recommendations can be met in order to define the damage profile.