bluuebunny/crossref_metadata_2025 huggingface dataset:
A diagnostic suite to assess NWP performance
Authors: Koh T.‐Y. , Wang S. , Bhatt B. C.
Published: June 2012

A suite of numerical weather prediction (NWP) verification diagnostics applicable to both scalar and vector variables is developed, highlighting the normalization and successive decomposition of model errors. The normalized root‐mean square error (NRMSE) is broken down into contributions from the normalized bias (NBias) and the normalized pattern error (NPE). The square of NPE, or the normalized error varianceα, is further analyzed into phase and amplitude errors, measured respectively by the correlation and the variance similarity. The variance similarity diagnostic is introduced to verify variability e.g. under different climates. While centered RMSE can be reduced by under‐prediction of variability in the model,αpenalizes over‐ and under‐prediction of variability equally. The error decomposition diagram, the correlation‐similarity diagram and the anisotropy diagram are introduced. The correlation‐similarity diagram was compared with the Taylor diagram: it has the advantage of analyzing the normalized error variance geometrically into contributions from the correlation and variance similarity. Normalization of the error metrics removes the dependence on the inherent variability of a variable and allows comparison among quantities of different physical units and from different regions and seasons. This method was used to assess the Coupled Ocean/Atmospheric Mesoscale Prediction System (COAMPS). The NWP performance degrades progressively from the midlatitudes through the sub‐tropics to the tropics. But similar cold and moist biases are noted and position and timing errors are the main cause of pattern errors. Although the suite of metrics is applied to NWP verification here, it is generally applicable as diagnostics for differences between two data sets.
The effect of wind waves on the development of river mouth bars
Authors: Nardin William , Fagherazzi Sergio
Published: June 2012

River deltas are among the most important environments on earth, housing productive ecosystems and a large fraction of the human population. The key process for delta development is the deposition of mouth bars in front of delta distributaries. Predicting mouth bar formation on marine coastlines is complex because of the interactions between waves, tides, water and sediment discharge. Here we study the effects of waves on mouth bar growth with the coupled sediment transport and wave model Delft3D‐SWAN. Our results show that wave characteristics (height, period, and direction) play an important role in the formation of mouth bars. In our numerical experiments waves affect bar development in three ways: by modifying the direction of the river jet, by increasing bottom shear stresses at the river mouth, and by changing bottom friction and hence increasing jet spreading. We further show that high waves with long period prevent the formation of mouth bars; in particular, wave angles between 45° and 60° are the least favorable to bar formation, likely producing a deflected river mouth.
Aquarius reveals salinity structure of tropical instability waves
Authors: Lee Tong , Lagerloef Gary , Gierach Michelle M. , Kao Hsun‐Ying , Yueh Simon , Dohan Kathleen
Published: June 2012

Sea surface salinity (SSS) measurements from the Aquarius/SAC‐D satellite during September–December 2011 provide the first satellite observations of the salinity structure of tropical instability waves (TIWs) in the Pacific. The related SSS anomaly has a magnitude of approximately ±0.5 PSU. Different from sea surface temperature (SST) and sea surface height anomaly (SSHA) where TIW‐related propagating signals are stronger a few degrees away from the equator, the SSS signature of TIWs is largest near the equator in the eastern equatorial Pacific where salty South Pacific water meets the fresher Inter‐tropical Convergence Zone water. The dominant westward propagation speed of SSS near the equator is approximately 1 m/s. This is twice as fast as the 0.5 m/s TIW speed widely reported in the literature, typically from SST and SSHA away from the equator. This difference is attributed to the more dominant 17‐day TIWs near the equator that have a 1 m/s dominant phase speed and the stronger 33‐day TIWs away from the equator that have a 0.5 m/s dominant phase speed. The results demonstrate the important value of Aquarius in studying TIWs.
PENGUIn/AGO and THEMIS conjugate observations of whistler mode chorus waves in the dayside uniform zone under steady solar wind and quiet geomagnetic conditions
Authors: Keika Kunihiro , Spasojevic Maria , Li Wen , Bortnik Jacob , Miyoshi Yoshizumi , Angelopoulos Vassilis
Published: June 2012

We perform a case study of conjugate observations of whistler mode chorus waves on the dayside made on 26 July 2008 by three THEMIS spacecraft and ground‐based ELF/VLF receivers at the Automatic Geophysical Observatories (AGO) in Antarctica supported by the U.S. Polar Experiment Network for Geospace Upper‐atmosphere Investigations (PENGUIn) project. The dayside chorus waves were excited during a period of no substorm activity with geomagnetic indices indicating quiet conditions (Dst ∼ −10 nT; AE < 200 nT). The solar wind dynamic pressure was almost constant during the chorus wave intensification. Conjugate observations in the outer magnetosphere confirm that the chorus intensification was localized within the radial distance R = 7–10 RE near noon (12.5 < MLT < 13.5 h). The waves persisted for at least 1.5 h in the same location, where field lines are not accompanied by off‐equatorial minimum‐B pockets but rather exhibit nearly zero dB/ds, the field‐aligned gradient in B‐magnitude, over a wide range of magnetic latitudes (∼±20°). The location did not seem to corotate with the Earth or drift with the energetic electrons. The chorus waves consisted of discrete, rising tone elements, propagating away from the magnetic equator, quasi‐parallel to the ambient magnetic field (wave‐normal angles < 20°). We conclude that the long‐lasting, localized, quiet time dayside chorus amplification was due to the nearly zero dB/ds conditions that occur naturally in the dayside uniform zone (DUZ), the transition region between the near‐Earth dipole and the compressed, off‐equatorial double‐minimum field configuration found closer to the magnetopause. We thus suggest that the magnetic field configuration in the dayside outer magnetosphere plays a key role in the generation of dayside chorus waves under quiet geomagnetic conditions.
A robust method to forecast volcanic ash clouds
Authors: Denlinger Roger P. , Pavolonis Mike , Sieglaff Justin
Published: June 2012

Ash clouds emanating from volcanic eruption columns often form trails of ash extending thousands of kilometers through the Earth's atmosphere, disrupting air traffic and posing a significant hazard to air travel. To mitigate such hazards, the community charged with reducing flight risk must accurately assess risk of ash ingestion for any flight path and provide robust forecasts of volcanic ash dispersal. In response to this need, a number of different transport models have been developed for this purpose and applied to recent eruptions, providing a means to assess uncertainty in forecasts. Here we provide a framework for optimal forecasts and their uncertainties given any model and any observational data. This involves random sampling of the probability distributions of input (source) parameters to a transport model and iteratively running the model with different inputs, each time assessing the predictions that the model makes about ash dispersal by direct comparison with satellite data. The results of these comparisons are embodied in a likelihood function whose maximum corresponds to the minimum misfit between model output and observations. Bayes theorem is then used to determine a normalized posterior probability distribution and from that a forecast of future uncertainty in ash dispersal. The nature of ash clouds in heterogeneous wind fields creates a strong maximum likelihood estimate in which most of the probability is localized to narrow ranges of model source parameters. This property is used here to accelerate probability assessment, producing a method to rapidly generate a prediction of future ash concentrations and their distribution based upon assimilation of satellite data as well as model and data uncertainties. Applying this method to the recent eruption of Eyjafjallajökull in Iceland, we show that the 3 and 6 h forecasts of ash cloud location probability encompassed the location of observed satellite‐determined ash cloud loads, providing an efficient means to assess all of the hazards associated with these ash clouds.
Stabilization of Mobile Mandibular Segments in Mandibular Reconstruction: Use of Spanning Reconstruction Plate
Authors: Yap Yan Lin , Lim Jane , Ong Wei Chen , Yeo Matthew , Lee Hanjing , Lim Thiam Chye
Published: June 2012

The fibular free flap is the gold standard for mandibular reconstruction. Accurate 3-dimensional contouring and precise alignment of the fibula is critical for reestablishing native occlusion and facial symmetry. Following segmental mandibulectomy, the remaining mandibular fragments become freely mobile. Various stabilization methods including external fixation, intermaxillary fixation, and preplating with reconstruction plate have been used. We describe a modification to the preplating technique. After wide resection of buccal squamous cell carcinoma, our patient had an 11-cm mandibular defect from the angle of the left mandible to the right midparasymphyseal region. A single 2.0-mm Unilock® (Synthes, Singapore) plate was used to span the defect. This was placed on the vestibular aspect of the superior border of the mandibular remnants before resection. Segmental mandibulectomy was then performed with the plate removed. The spanning plate was then reattached to provide rigid fixation. The fibular bone was contoured with a single osteotomy and reattached. The conventional technique involves molding of the plate at the inferior border of the mandible. This is time-consuming and not possible in patients with distorted mandibular contour. It is also difficult to fit the osteotomized fibula to the contoured plate. In comparison, the superiorly positioned spanning plate achieve rigid fixation of the mandible while leaving the defect completely free and unhampered by hardware, allowing space for planning osteotomies and easier fixation of the neomandible. Using this modified technique, we are able to recreate the original mandibular profile with ease.
Comparison of Inflammatory Cytokines Expression in Intervertebral Disk Protrusion with or without Low Back Pain
Authors: Zheng Z. , Liu H. , Yang H. , Wang J. , Li Z.
Published: June 2012

Introduction

It is recognized that inflammation is tightly associated with intervertebral disk (IVD) degeneration and low back pain (LBP), but the association between IVD degeneration and LBP is still controversial. The aim of this study was to demonstrate the difference of inflammation cytokines expression in the IVD herniation patients nucleus pulposus with or without the presence of LBP, elucidate the role of inflammation cytokines for pain generation.

Materials and Methods

Surgical IVD tissues were harvested from IVD protrusion patients with LBP ( n = 20) or without LBP ( n = 20). Immunohistochemistrical analysis was performed to examine the expression of interleukin-1β (IL-1β), tumor necrosis factor (TNFα), inducible nitric oxide synthetase (iNOS), and substance P in these IVD samples. Nine evenly spaced separate 10× magnification fields for each tissue sample and antibody target were evaluated for the immune-reactivity positive cell percentage to compare the inflammation cytokines expression between the two groups.

Results

Immunohistochemistrical analysis showed that IL-1β, TNFα, iNOS, and substance P were expressed in both groups. The immune-reactivity positive cell percentage of IL-1β, TNFα, iNOS, and substance P are 18.44 ± 12.17, 23.9 ± 9.32, 21.86 ± 11.57, and 37.44 ± 14.40, respectively, in group of intervertebral disk (IVD) protrusion patients with LBP, whereas 17.82 ± 4.90, 17.56 ± 9.54, 29.74 ± 5.62, and 24.98 ± 10.36 in group of IVD protrusion patients without LBP. There were no significant statistical differences for the immunoreactivity positive cell percentage of IL-1β, TNFα, iNOS, and substance P between the two groups, but the expression of substance P was stronger in group of IVD protrusion patients with LBP.

Conclusion

Similar expression pattern of IL-1β, TNFα, and iNOS between both groups might indicate that they are not associated with LBP generation. However, substance P overexpression in IVD may be responsible for LBP pathomechanism. I confirm having declared any potential conflict of interest for all authors listed in this abstract Yes Disclosure of Interest None declared
Efficacy of Epidural Administration of Anti-Interleukin-6 Receptor Antibody onto Spinal Nerve for Treatment of Sciatica
Authors: Ohtori S. , Miyagi M. , Eguchi Y. , Inoue G. , Orita S. , Aoki Y. , Ishikawa T. , Kamoda H. , Suzuki M. , Kubota G. , Sakuma Y. , Oikawa Y. , Takahashi K.
Published: June 2012

Introduction

Interleukin-6 (IL-6) is considered to play a crucial role in the radicular pain caused by lumbar spinal stenosis (LSS). However, efficacy of inhibition of IL-6 for sciatica in patients with LSS has not been clarified. The purpose of the current study was to examine the effect of the anti-IL-6 receptor monoclonal antibody, tocilizumab, on radicular pain by its epidural administration onto spinal nerves in patients with LSS.

Materials and Methods

A total of 60 patients with low back and radicular leg pain caused by spinal stenosis were investigated. In 30 patients, we infiltrated 2.0 mL of lidocaine and 80 mg of tocilizumab onto the affected spinal nerve, and 2.0 mL of lidocaine and 3.3 mg of dexamethasone were used in 30 patients. Low back pain (LBP), leg pain, and leg numbness were evaluated during 1 month after spinal nerve infiltration.

Results

Infiltration of tocilizumab was more effective than dexamethasone for leg pain (3 days, 1, 2, and 4 weeks), LBP (3 days, 1, 2, and 4 weeks), and leg numbness (3 days, 1 and 2 weeks). No adverse event was observed in either group.

Conclusion

Our results indicate that epidural administration of an anti-IL-6 receptor monoclonal antibody and, tocilizumab, onto the spinal nerve produced reduction of radicular leg pain, numbness, and LBP without adverse event. IL-6 may be one of the inducers of pain caused by spinal stenosis in humans. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared
Heart Rate Variability in Sciatica Patients Referred to Spine Surgery
Authors: Södervall J. , Karppinen J. , Puolitaival J. , Siltala J. , Kiviniemi A. , Tulppo M. , Hautala A.
Published: June 2012

Introduction

There is some data that pain patients may have impaired autonomic nervous system function assessed by heart rate variability (HRV). However, only few studies have evaluated the effect of low back disorders on HRV. In this study, we evaluated whether HRV differs between sciatica patients referred to spine surgery and age-matched healthy controls.

Materials and Methods

We measured HRV in standing position (5 minutes) after 10 minutes rest for patients ( n = 201, age 42 ± 11 years, 113 men and 88 women) and healthy controls ( n = 138, age 42 ± 11 years, 39 men and 99 women). Vagally mediated high frequency (HF) power of R-R intervals and low-to-high frequency (LF/HF) ratio as an index of sympathovagal balance were analyzed. Pain intensity was assessed by 100-mm visual analog scale (VAS) and perceived disability by Oswestry low back pain disability index. Analysis of variance and chi-square test were used to analyze differences between groups, and correlation analysis for the associations between pain and HRV.

Results

Oswestry index (37 ± 14 vs. 2 ± 3%) and VAS (5.8 ± 2.5 vs. 0.6 ± 1.0 cm) differed between the patients and controls ( p < 0.0001 for both). Body mass index was higher ( p < 0.0001) in patients (26.4 ± 4.4 kg/m2) compared with controls (23.9 ± 3.6 kg/m2). There were more smokers among patients ( p < 0.0001) and gender distribution differed between the groups ( p < 0.0001). Groups did not differ from each other in relation to physical activities and comorbidities. HF power was 4.5 ± 1.2 ln ms2 for patients and 5.1 ± 1.2 ln ms2 for controls ( p < 0.0001). LF/HF ratio was higher in patients (7.9 ± 6.4) compared with controls (5.8 ± 5.2) ( p = 0.002). After adjusting with sex, smoking, and BMI, HF power still differed between the groups ( p = 0.003), but the difference between groups disappeared in LF/HF power ( p = 0.134). Among patients, Oswestry index and VAS did not correlate with HRV ( r = −020 to −061).

Conclusion

Sciatica patients referred to spine surgery had decreased vagal activity compared to age-matched healthy controls. Impaired functional capacity caused by pain or pain intensity were not associated with vagal activity among patients. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared
Regulation of Neurotrophic Factor Expression in Nerve Cells and Intervertebral Disk Cells by Inflammatory Cytokines, Implications for Pain Pathways
Authors: Thomas S. , Colletta R. , Phillips K. L. , Chiverton N. , Cross A. , Le Maitre C. L.
Published: June 2012

Introduction

Intervertebral disk (IVD) degeneration and prolapse contribute significantly to low back pain and sciatica cases. Within the IVD, the nucleus pulposus cells are known to produce a number of catabolic cytokines which have been shown to elicit a wide range of effects including increased production of degradation enzymes and decreased production of matrix molecules. Here, we investigate the hypothesis that cytokines induce neurotrophic and angiogenic factors in nucleus pulposus cells and nerve cells and induce neurite outgrowth within nerve cells.

Materials and Methods

Human NP cells were isolated via collagenase digestion from human IVD obtained from surgical samples. Following expansion in monolayer culture, cells were transferred to alginate bead cultures at P2 and maintained for 2 weeks before stimulation with cytokines to enable re-differentiation to take place. Cells were then stimulated with IL-1 (0.001 to 100 ng/mL), IL-6 (1 to 100 ng/mL), or IL-8 (1 to 100 ng/mL) for 48 hours, RNA extracted and real time PCR performed to investigate expression of nucleus growth factor (NGF), BDNF, NTF3, and VEGF together with the housekeeping genes GAPDH and 18 s. In addition, SHSY-5Y nerve cell line were cultured in the presence of retinoic acid for 7 days before stimulation with IL-1, IL-6, IL-8, or TNF (1 to 100 ng/mL) to investigate the gene expression of NGF, BDNF, and NTF3 together with effects on neurite outgrowth.

Results

Human NP cells showed a biphasic response to IL-1 in terms of NGF expression with expression decreased at low doses of IL-1 (0.001–0.01 ng/mL) but an increase in NGF expression at high IL-1 doses (1 ng/mL–100 ng/mL) (Fig. 1). A Small but nonsignificant increase in NTF3 was seen following IL-1 stimulation, whereas IL-6 treatment of NP cells showed a 10-fold increase in NTF 3 expression in some patient samples. Within SH-SY5Y cells interestingly, NGF and BDNF expression was not observed but NTF-3 was downregulated by IL-1 and IL-8 treatments and stimulated by IL-6 stimulation. TNF and IL-1 appeared to induce the greatest effects on neurite outgrowth and number of neurites per cell, both of which increased at doses above 1 ng/mL stimulation. VEGF was also upregulated in human NP cells following IL-1 stimulation even at low doses.

Conclusion

Here, we demonstrate that a number of cytokines which are upregulated during human disk degeneration and prolapse induce a number of neurotrophic factors and angiogenic factors within human NP cells in 3D cultures. A number of cytokines also induce neurotrophic factor expression and neurite outgrowth in a nerve cell line suggesting a role for these cytokines both within the nerve ingrowth seen in an intact disk and intact disks and following prolapse. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared
Clinical Analysis following Minimally Invasive Treatment of Lumbar Spinal Stenosis with Interspinous Devices: Where We Are and Where We Go
Authors: Grasso G. , Certo F. , Pirrone A. G. , iacopino D.
Published: June 2012

Introduction

Insertion of an interspinous device has become a common procedure for the treatment of different clinical pictures of degenerative spinal disease. We present our experience with patients treated with interspinous devices because affected by claudication neurogenic, by lumbar disk herniation (LDH) where the interspinous system has been inserted following microdiscectomy.

Materials and Methods

This study included patients ( n = 200) with neurogenic intermittent claudication (NIC) secondary to LSS (group 1) and patients ( n = 150) with LDH (group 2) in whom the interspinous device has been implanted following radicular decompression in a period spanning 6 years. The latter have been compared with a homogenous group of patients ( n = 150) where no interspinous system has been implanted following microdiscectomy (group 3). We observed clinical and neuroradiological findings preoperatively and 3, 6, 12 months and every year postoperatively using dedicated questionnaires (Zurich Claudication Questionnaire, SF-36, ODI) and X-ray imaging.

Results

After 6 years of surgical treatment 85% of patients of group 1 presented a very good improvement of symptoms and 90% of patients referred satisfaction for surgery. Only 2% of the cases needed re-operation to change the implant. In one case the device was removed and in two cases we observed recurrence of symptoms and we changed surgical procedure. Overall patients of group 2 presented significantly less lumbar disk recurrences compared with group 3 ( p < 0.05) and better clinical outcome when compared with the same group ( p < 0.01).

Conclusion

According to our features, no significant complications were associated with such kind of surgery. In particular, interspinous systems showed significant and clinically meaningful improvements in pain and disability for up to 6 years. Furthermore, interspinous devices have shown better clinical outcome and less lumbar disk recurrences when associated with standard microdiscectomy. These data, however, need further studies and a longer period of follow-up. I confirm having declared any potential conflict of interest for all authors listed on this abstract No Disclosure of Interest None declared
The Prognostic Role of Modic Changes for Lumbar Discectomy: A Prospective Study
Authors: Määttä J. , Leinonen V. , Niinimäki J. , Koskelainen T. , Mäkelä P. , Pesälä J. , Haapea M. , Nyyssönen T. , Savolainen S. , Airaksinen O. , Kyllönen E. , Cheung K. M. , Karppinen J.
Published: June 2012

Introduction

There is a controversy regarding the prognostic role of Modic changes (MC's) for lumbar discectomy. The aim of this study was to evaluate whether Modic changes affect the results of lumbar discectomy 1 year after surgery.

Materials and Methods

The study population consisted of 180 sciatica patients from Northern and Eastern Finland who underwent discectomy. Pain intensity (low back and leg pain) and disability on Oswestry Disability Index (ODI) were evaluated preoperatively and 1 year after surgery. Lumbar MC's on magnetic resonance imaging were classified into: “No MC,” “Type I” (Type I or I/II), and “Type II” (Type II, II/III, or III). The analyses were performed using the analysis of covariance (ANCOVA) with adjustments for age, gender, and disk degeneration (DD) sum score.

Results

At baseline, 83 (46%) patients had MC's. Of MC's, 33% were Type I. Patients with MC's were older, more likely female and had a higher degree of DD than patients without MC's. Patients with Type I MC's had smaller improvement in ODI than patients with No MC ( p = 0.045) or Type II MC's ( p = 0.037). The improvements in low back and leg pain were similar than in ODI but the differences were not significant.

Conclusion

Type I MC's indicated a poorer prognosis of lumbar discectomy. The previous contradictory results may be due to smaller study sample sizes. Patients with ‘Type I’ MC's had smaller disability improvement than patients without MC's or with Type II MC's 1 year after discectomy. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared
Course of Recovery in Patients with Acute Low Back Pain: Does Depression Matter?
Authors: Melloh M. , Käser A. , Rolli Salathé C. , Elfering A.
Published: June 2012

Introduction

While there is extensive knowledge on the course of acute low back pain (LBP), little is known about the course of recovery of acute LBP patients as a function of depression. The aims of our study were to determine if the course of recovery in patients with acute LBP differs in relation to the presence/absence of depression and to identify the best time point for an intervention against LBP-associated depression.

Materials and Methods

This is a prospective cohort study of 286 patients with acute LBP. Patients were assessed at baseline and followed up over 6 months addressing psychological, occupational, biomedical, and demographic/lifestyle factors. Recovery was defined as improvement in functional limitation measured by the Oswestry disability index (ODI); depression was defined by the Zung depression scale. Repeated-measures analysis of covariance (ANCOVA) was employed with ODI as repeated factor, age, gender, and body mass index as covariates, depression and all other potential prognostic factors as between-subject factors. A second ANCOVA was performed with depression as dependent variable and functional limitation, pain intensity, and job stressors as potential predictor variables.

Results

A total of 18% of study participants were classified as depressive. In these patients, the course of recovery was slower than in nondepressive patients. ODI scores in the nondepression-LBP group decreased over time, whereas scores in the depression-LBP group remained at the same level (F(3.295, 431.607) = 4.63; p < 0.01, partial η2 = 0.034; Fig. 1). High functional limitation (F(1.261) = 15.79; p < 0.001, partial η2 = 0.057), high pain intensity (F(1.260) = 6.84; p < 0.01, partial η2 = 0.026), and a high job stressor index (F(1.252) = 8.95; p < 0.01, partial η2 = 0.034) were predictors of depression at baseline. Further, the presence of depression caused maintenance of LBP especially after 6 weeks.

Conclusion

The presence of depression has a negative influence on the course of recovery in patients presenting with a new episode of LBP. Therefore, depression should be included in screening instruments for patients with acute LBP to identify those at risk of delayed recovery at an early stage. Further research is required investigating interventions at different time points, to identify the optimal time at which to treat acute LBP patients with concomitant depression to reduce the socioeconomic costs of delayed recovery. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared
Personal, Psychosocial, and Occupational Resources for Preventing Persistent Low Back Pain in Primary Care
Authors: Melloh M. , Rolli Salath C. , Käser A. , Elfering A.
Published: June 2012

Introduction

Socioeconomic costs of persistent low back pain (LBP) exceed the costs of acute and subacute LBP by far. This makes the early identification of modifiable factors of the progression of acute/subacute LBP essential to the persistent state. Modifiable protective factors could be addressed proactively, for example, in workplace interventions, to limit the associated socioeconomic burden. Aim of our study was to identify modifiable protective factors against the progression of acute/subacute LBP to the persistent state.

Materials and Methods

Prospective cohort study of patients attending a health practitioner for their first episode of acute/subacute LBP. Patients were assessed at baseline addressing occupational, psychological, biomedical and demographic lifestyle factors and followed up over 12 weeks according to the recommendations from the Multinational Musculoskeletal Inception Cohort Study (MMICS) Statement. We completed Pearson correlations between these baseline factors and the presence of nonpersistent LBP at 12-week follow-up. For those factors found to be significant, multivariate logistic regression analyses were performed.

Results

The final two predictor model (χ2 = 34.7, df = 7, p < 0.001) included “social support” (OR 1.78; 95% CI, 1.20–2.66) and “mental health” (OR 1.06; 95% CI, 1.02–1.10). All factors and control variables predicted 24% variance in nonpersistent LBP. The accuracy of the model was 72%, with 81% (sensitivity) of nonpersistent and 60% (specificity) of persistent LBP patients correctly identified.

Conclusion

In this study of patients with acute/subacute LBP from a primary care setting, good “social support” reduced the likelihood of persistent LBP at 12 weeks. Findings from this study confirm the importance of personal and psychosocial resources for preventing the development of persistent LBP. Resources, easily identified with use of widely available screening tools, will facilitate the provision of necessary strategies to reduce the societal and financial burden of persistent LBP. The benefit of including modifiable protective factors such as “social support” in screening tools is that these factors can be addressed in primary and secondary prevention, for example, in workplace intervention. Further research is required to confirm the role of different types of “social support” and “social support at work” regarding their prognostic influence on the development of persistent LBP. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared
Intervertebral Disk Degeneration is not a Direct Cause of Pain Behavior: An Experimental Study Using a Disk Puncture Model in Rats
Authors: Zheng Z. , Liu H. , Li Z. , Wang J. , Yang H. , Sribastav S. S.
Published: June 2012

Introduction

Low back pain (LBP) is a common symptom in patients with lumbar diseases. But the relationship between lumbar intervertebral disk degeneration and LBPis still a controversial issue. Some animal models were used to discuss this issue in prior studies. A recent study1 suggested that the pain behavior changes might be related to the epidural presence of the oozed nucleus pulposus in the posterior rat disk puncture model. In this study, an anterior rat disk puncture model was applied to exclude the epidural presence of nucleus pulposus, and the objectives of this study were to establish an intervertebral disk degeneration model in rats and to analyze the relationship between disk degeneration and pain behavior changes in this model.

Materials and Methods

Total 18 male Sprague-Dawley rats with an average bodyweight of 230 g were used in this study. The anterior intervertebral disk annular puncture model was established as follows: the L5/6 lumbar disks were punctured using a 0.4-mm-diameter injection needle under microscope in nine rats; another nine rats receiving same surgery were considered as control group. Magnetic resonance imaging (MRI) of the punctured rats' spine was taken to confirm the degeneration of the disk. Behavioral tests including assessment of motor function, mechanical threshold, and thermal withdrawal latency were performed before and after surgery in both groups. The behavior tests were performed on days 1, 3, 7, 14, 21, 30, and 45 after the surgery.

Results

MRI results showed visible degeneration in rats at about 3 weeks after disk puncture (Fig. 1A). There was no degenerative change in the control group in all time points. Regarding motor function, both groups exhibited normal gait during the entire observation period. No significant statistical difference was found between the two groups in both mechanical threshold and thermal withdrawal latency tests at different time points (Fig. 1B, C).

Conclusion

The degenerative lumbar intervertebral disk model in rats was successfully established by anterior disk annulus needle puncture. The degeneration of the lumbar disk caused by anterior puncture could not induce pain behavior change in rats. I confirm having declared any potential conflict of interest for all authors listed on this abstract No Disclosure of Interest None declared Elin Nilsson, Toshio Nakamae, Kjell Olmarker. Pain behavior changes following disc puncture relate to nucleus pulposus rather than to the disc injury per se: an experimental study in rats. The Open Orthopaedics Journal 2011;5:72–77.
Effect of Spino-Pelvic Sagittal Balance on Degree of Disk Degeneration in the Lumbar Spine
Authors: Zheng Z. , Liu H. , Sribastav S. S. , Li Z. , Wang J. , Yang H.
Published: June 2012

Introduction

Recent studies have focused on spino-pelvic sagittal balance. Changes in sagittal balance could alter the load on the spine and may affect spinal mobility. Increasing recognition of the clinical impacted that sagittal alignment has on back pain and adjacent segment degeneration. But recent studies focused only on the effects of lumbar sagittal alignment to the disk degeneration. The relationship between spino-pelvic sagittal balance and lumbar disk degeneration has yet to be determined. The objective of this research was to study the effect of spino-pelvic sagittal balance on degree of disk degeneration in the lumbar spine.

Materials and Methods

The lumbar spine magnetic resonance imaging (MRI) and whole spine X-ray of 32 patients (13 males and 19 females) with a mean age of 57.92 years (range: 25 to 84 years) were retrospectively evaluated. Patients with history of prior spinal surgery, serious congenital anomalies, infection, spinal trauma, tumorn or ankylosing spondylitis were excluded from the study. In every patient, spino-pelvic sagittal parameters such as sagittal vertical axis (SVA), thoracic Kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), C7 tilt (C7T), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), spino-sacral angle (SSA), spino-pelvic angle (SPA), T1 spiono-pelvic inclination (T1-SPI), and T9 spino-pelvic inclination (T9-SPI) were measured in the whole spine X-ray to evaluate the sagittal balance. And lumbar intervertebral disk degeneration grade for each level (L1/2, L2/3, L3/4, L4/5 and L5/S1) was assessed using the lumbar MRI according to the Pfirrmann grading. The relationship between sagittal parameters and disk degeneration grade was analyzed.

Results

There was significant correlation between SVA and disk degeneration grade in level L5/S1 ( r = 0.565, p = 0.003) but not significant correlation in level L1/2, L2/3, L3/4 or L4/5. Similarly, significant correlation has been determined between C7T and degree of disk degeneration at the level of L5/S1 ( r = 0.557, p = 0.004), between PT and L2/3 ( r = 0.519, p = 0.008), between SSA and L5/S1 ( r = 0.466, p = 0.019), between SPA and L2/3 ( r = 0.466, p = 0.019), and between T1-SPI and L5/S1 ( r = 0.398, p = 0.049). No significant effect was detected for the degree of disk degeneration with the changes in spino-pelvic parameters like TK, TLK, LL, PI, SS, and T9-SPI.

Conclusion

Spino-pelvic parameters such as SVA, C7T, SSA, and T1-SPI may have effects on the degeneration of L5/S1 disk. And parameters such as SPA and PT may have effects on the degeneration of L2/3 disk. Changes in spino-pelvic parameters may influence the degree of disk degeneration, but all the parameters are not equally involved in the degree of disk degeneration. I confirm having declared any potential conflict of interest for all authors listed on this abstract No Disclosure of Interest None declared
Association of Facet Tropism with Lumbar Disk Herniation
Authors: Chadha M.
Published: June 2012

Introduction

Study Design

Analytical cross-sectional hospital-based cohort study.

Objective

(1) To determine whether there is an association between facet tropism and the occurrence of lumbar disk herniation at that level. (2) In patients with facet tropism at the herniated disk level, to determine whether there is an association between facet tropism and the side of disk herniation (sagittal or coronal).

Background

Facet tropism is defined as asymmetry between left and right facet joint angles and is postulated as a possible etiological cause in occurrence of disk herniation. A correlation in literature is still being debated.

Materials and Methods

Total 60 patients (18 to 40 years) with single disk herniation (L3-L4, L4-L5, or L5-S1) were selected. Exclusion criteria included multiple/recurrent disk herniation, spondylolisthesis, transitional vertebra, scoliosis, previous surgery/trauma/infection, and significant facetal arthropathy. Facet angles were measured using 3 Tesla MRI by two surgeons and mean taken to minimize bias. Facet tropism was defined as difference of 10 degrees in facet joint angles between right and left sides. Normal adjacent disk was used as control. We also examined if disk herniated towards the side of more coronally oriented facet.

Results

Overall we found a statistically significant association of facet tropism with lumbar disk herniation ( p = 0.0009). However, analyzing each level separately, an association of facet tropism with lumbar disk herniation was found to be statistically significant at the L5S1 level ( p = 0.0094) but not at L4L5 level ( p = 0.145). Of 19 cases having tropism at the herniated disk level, the disk had herniated towards the sagittally oriented facet in 13 ( p = 0.11).

Conclusion

Statistically significant association exists between facet tropism and lumbar disk herniation at L5-S1. Same does not hold true at L4-5. There is no statistically significant association between facet tropism and the side of the disk herniation (sagittal or coronal) but the numbers were small. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared
Regulation of Chemokine Expression by Interleukin-1 in Human Intervertebral Disk Degeneration
Authors: Phillips K. L. E. , Chiverton N. , Haddock G. , Bunning R. , Cross A. , Le Maitre C.
Published: June 2012

Introduction

It is established that Interleukin-1 (IL-1) is expressed by native nucleus pulposus (NP) cells and that disregulated expression is associated with the pathogenesis of IVD degeneration1. IL-1 has been shown to regulate diverse cellular functions within the IVD including those related to catabolic and anabolic activities2. Here the regulatory potential of IL-1 on chemokines that we have previously identified within the human IVD is investigated to address the hypothesis that regulatory interrelationships exist between cytokines and chemokines in the IVD.

Materials and Methods

Primary human NP cells cultured in alginate beads were subjected to 48 hours treatment with IL-1. RNA extracted from these cultures was used in qRT-PCR gene expression analysis to determine the effects of treatment on the expression of selected target chemokine genes. Cell culture supernatants from these cultures were used to determine the effects of treatment on protein production of selected chemokines.

Results

Constitutive expression of CXCL8, CCL2, and CCL7 was observed in alginate bead cultured primary human NP cells. Following 48 hours IL-1 treatment expression of CXCL8 and CCL2 was upregulated (Fig. 1A). Constitutive expression of IL-1 and CCL3 was not observed in alginate cultured primary human NP cells however, expression was induced following 48 hours IL-1 treatment (Fig. 1B).

Conclusion

This study demonstrates the regulatory potential of IL-1 in relation to a number of chemokines some of which have not been shown previously and adds to the body of evidence implicating IL-1 as a key regulator of NP cell biology. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared Le Maitre et al. Arthritis Research and Therapy 2007;7:R732-R745 Le Maitre et al. Arthritis Research and Therapy 2007;9:R77
Characterization of miRNA Expression in Human Lumbar Disks
Authors: Ohrt-Nissen S. , Dahl B. , Friis-Hansen L. , Nielsen F. C. , Vikeså J. , Lajer C. , Rossing M. , Døssing K.
Published: June 2012

Introduction

MicroRNA (miRNA) are short ∼22 nucleotide RNA sequences that regulate mRNA translation, and more than 900 humans miRNAs are known. miRNAs have been shown to play a role in synthesis of inflammatory mediators. Since inflammation play a role in intervertebral disk degeneration, we wanted to isolate miRNA from human lumbar intervertebral disks and subsequently characterize the difference in miRNA expression between the annulus fibrosus (AF) and nucleus pulposus.

Materials and Methods

A total of 14 patients undergoing anterior interbody fusion for degenerative disk disease of the lumbar spine were included. During surgery, biopsies from the intervertebral disks (IVD) were immediately stored in RNA-Later, transported to the laboratory within a day, and then frozen at −80°C. RNA extraction was performed using the Trizol method. Global miRNA expression analysis was performed using the Affymetrix GeneChip(r) miRNA array.

Results

We developed a method allowing for the extraction of miRNA from human IVDs, yielding 1 to 4 microgram of total RNA Per 100 mg of disk. Total 27 miRNAs had a higher expression in the fibrosus and 10 had the highest expression in the pulposus. Among the top 15 signaling pathways most likely to be controlled by these miRNA's were the TGFβ, PDGF, IGF EGF, and actin cytoskeletal pathway.

Conclusion

This is the first time miRNA have been demonstrated in the human IVD. The miRNA expression differs between the miRNA expressed in the nucleus pulposus and AF. The identified miRNAs control signaling pathways is important for maintenance of the IVD. Future studies may determine the importance of miRNA in the development of IVD disease. I confirm having declared any potential conflict of interest for all authors listed on this abstract No Disclosure of Interest None declared
Vertebral Bone Remodeling after Disk Degeneration-Quantitative Microanalysis in a Porcine Nucleotomy Model
Authors: Omlor G. , Lorenz S. , Huettner F. , Holschbach J. , Richter W. , Gühring T.
Published: June 2012

Introduction

Changes in vertebral endplate sclerosis and permeability seem to be a crucial aspect in the course of disk degeneration. Detailed information on microstructural changes of the subchondral bone of the endplates and the trabecular vertebral bone is missing, especially when bony remodeling runs parallel with disk remodeling or not. Therefore, the goal of this study was to analyze this in an established disk degeneration model on minipigs.

Materials and Methods

Animals were divided into three groups. Group 1 and 2 received partial nucleotomy with a 16G-biopsy-cannula to induce moderate disk degeneration and were followed for 13 and 24 weeks, respectively. Group 3 did not receive surgery and served as controls. A total of 24 disks and 48 endplates with subchondral bone and trabecular vertebral bone were analyzed histologically and by quantitative micro-CT. Standardized elliptical volumes of interest were analyzed by Skyscan-micro-CT-software.

Results

Both group 1 and 2 showed disk degeneration with significant loss of disk height, higher disk- and endplate-degeneration-scores, fibrous scarring, and loss of notochordal cells ( p < 0.05 compared to controls). Micro-CT revealed less sclerosis (BV/TV) and reduced trabecular thickness of subchondral bone underneath the endplates 13 weeks after nucleotomy compared to untreated controls ( p < 0.05 group 1 vs. group 2 and 3); after 24 weeks, however, values turned back to those of controls again. The same correlation was found in more distant trabecular vertebral bone, though BV/TV values were lower. Separate analysis of changes above and below the operated disk did not show differences.

Conclusion

Contrary to the concept of simultaneous bony endplate sclerosis and disk degeneration, we found reduced BV/TV and trabecular thickness early after nucleotomy induced disk degeneration. At later stages of disk degeneration, sclerosis was not higher than in healthy controls, indicating that disk degeneration can proceed independently from endplate sclerosis. The vertebral bone is highly reactive to disk disturbances but does not automatically react with increased sclerosis. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared
New Validated Classification for Intervertebral Disk Histology
Authors: Rutges J. , Duit R. , Kummer J. , Bekkers J. , Oner F. , Castelein R. , Dhert W. , Creemers L.
Published: June 2012

Introduction

Intervertebral disk degeneration (IVD) is considered as one of the main causes of chronic low back pain. Consequently, the research on the pathophysiology of IVD degeneration is significantly intensified and new treatment strategies are being developed. In most basic science and pre-clinical studies, histology is an important outcome variable. Nevertheless, an adequately validated histological classification for IVD degeneration is still lacking. Moreover, the existing classifications are elaborate and difficult to use for inexperienced observers. Therefore the aim of this study was to develop and to validate a new histological classification for IVD degeneration. This new classification subsequently was compared to the frequently used nonvalidated classification of Boos et al.

Materials and Methods

The new classification was applied to sections from 61 human IVDs from all macroscopic degeneration grades. The sections were scored twice by two independent inexperienced observers, twice by an experienced IVD researcher, and once by an experienced pathologist. For comparison, the sections were also scored according to the classification described by Boos et al by two experienced IVD researchers. Macroscopic grading according to Thompson et al and glycosaminoglycan (GAG) content were used for validation of both classifications.

Results

The new classification had an excellent intra- and a good interobserver reliability, with intraclass correlation coefficients (CC) of 0.84 and 0.73, respectively. Intra and interobserver reliability was comparable for both experienced and inexperienced observers. Statistically significant correlations were found between the new classification, the macroscopic score, GAG content in the nucleus pulposus and age, CC 0.791, −0.620 and 0.687, respectively. The reliability of the Boos classification was comparable to the new classification, however, the CCs for the macroscopic score, GAG content, and age were all low.

Conclusion

The new histological classification for IVD degeneration is a valuable instrument for evaluating IVD degeneration in human IVD sections and is reliable to use for both inexperienced and experienced researchers. This classification could significantly contribute to the standardization of histological grading of degenerative IVDs. I confirm having declared any potential conflict of interest for all authors listed on this abstract No Disclosure of Interest None declared