Solitary bone plasmacytoma of spine with involvement of intervertebral disk: a case report and literature review

Primary malignant bone tumors of the spine are exceedingly rare, with solitary bone plasmacytoma (SBP) representing approximately 30% of all cases. Radiological assessments are crucial for localizing SBP and for ruling out a diagnosis of multiple myeloma (MM). Imaging features resembling a "mini-brain" appear to be distinctive for SBP. Vertebral lesions accompanied by adjacent disc space involvement typically suggest spinal infections, while the potential for SBP involvement is often overlooked. We present a case of a 61-year-old female with SBP who exhibited thoraco-lumbar spine destruction and adjacent disc space involvement. The patient sought treatment at our medical center due to lumbodorsal pain radiating bilaterally to the inguinal regions. Radiological findings revealed an osteolytic lesion involving the intervertebral disc, making it challenging to distinguish between tumor and inflammation. A biopsy of the vertebral lesion confirmed the diagnosis of SBP, which was further supported by laboratory results. Post-diagnosis, the patient underwent radiotherapy, receiving a total dose of 4000 Gy, which alleviated her symptoms. We also provide a comprehensive literature review on SBP with disc involvement to aid both clinical and radiological diagnoses.

Understanding the management of pediatric spondylodiscitis based on existing literature; a systematic review

BACKGROUND

Spondylodiscitis (SD), a rare disease in children, poses diagnostic challenges due to non-specific presenting symptoms, scarcity in incidence, and difficulty expressing pain in non-verbal children.

METHOD

A comprehensive search was conducted on three databases, including PubMed/Medline, Web of Science, and Scopus until March 2023. The inclusion criteria were studies that investigated the clinical characteristics, treatment, and complications of children's spondylodiscitis. Full text of cross-sectional and cohort studies were added. The quality assessment of cohort studies was conducted using the Newcastle-Ottawa Quality Assessment Scale. The search, screening, and data extraction were performed by two researchers independently.

RESULT

Clinical manifestations of discitis in children are nonspecific, such as back pain, fever, reduced ability or inability to walk or sit, limping, and reduced range of movements. The mean delay in the time of diagnosis was 4.8 weeks. The most affected site of all the studies was the lumbar spine. 94% of studies reported increased inflammatory markers such as white blood cell count, C-reactive protein, and erythrocyte sedimentation rate. Less than 30% of patients had positive blood cultures and biopsy findings. The most common microbiological results (64%) were Staphylococcus Aureus and Kingella kingae. In radiographic evaluation, intervertebral disk narrowing, lumbar lordosis reduction, loss of disk height, and destruction of the vertebral body have been reported. In all studies, antibiotic therapy was initiated; in 52% immobilization was employed, and 29% of studies reported surgery was performed, and the follow-up period differed from 1.5 months to 156 months. 94% of studies reported complications such as vertebral body destruction, back pain, kyphosis, reduced range of movement, scoliosis, and neurological complications.

CONCLUSION

Spondylodiscitis is an uncommon, heterogeneous, multifactorial disease with resulting difficult and delayed diagnosis. Due to its morbidity, it is essential to investigate children with refusal to walk, gait disturbances, or back pain, particularly when associated with elevated inflammatory markers.

Celecoxib alleviates nociceptor sensitization mediated by interleukin-1beta-primed annulus fibrosus cells

PURPOSE

This study aims to analyze the effect of pro-inflammatory cytokine-stimulated human annulus fibrosus cells (hAFCs) on the sensitization of dorsal root ganglion (DRG) cells. We further hypothesized that celecoxib (cxb) could inhibit hAFCs-induced DRG sensitization.

METHODS

hAFCs from spinal trauma patients were stimulated with TNF-α or IL-1β. Cxb was added on day 2. On day 4, the expression of pro-inflammatory and neurotrophic genes was evaluated using RT-qPCR. Levels of prostaglandin E2 (PGE-2), IL-8, and IL-6 were measured in the conditioned medium (CM) using ELISA. hAFCs CM was then applied to stimulate the DRG cell line (ND7/23) for 6 days. Then, calcium imaging (Fluo4) was performed to evaluate DRG cell sensitization. Both spontaneous and bradykinin-stimulated (0.5 μM) calcium responses were analyzed. The effects on primary bovine DRG cell culture were performed in parallel to the DRG cell line model.

RESULTS

IL-1ß stimulation significantly enhanced the release of PGE-2 in hAFCs CM, while this increase was completely suppressed by 10 µM cxb. hAFCs revealed elevated IL-6 and IL-8 release following TNF-α and IL-1β treatment, though cxb did not alter this. The effect of hAFCs CM on DRG cell sensitization was influenced by adding cxb to hAFCs; both the DRG cell line and primary bovine DRG nociceptors showed a lower sensitivity to bradykinin stimulation.

CONCLUSION

Cxb can inhibit PGE-2 production in hAFCs in an IL-1β-induced pro-inflammatory in vitro environment. The cxb applied to the hAFCs also reduces the sensitization of DRG nociceptors that are stimulated by the hAFCs CM.

Structure-function characterization of the transition zone in the intervertebral disc

Understanding the structure-function relationship in the intervertebral disk (IVD) is crucial for the development of novel tissue engineering strategies to regenerate IVD and the establishment of accurate computational models for low back pain research. A large number of studies have improved our knowledge of the mechanical and structural properties of the nucleus pulposus (NP) and annulus fibrosus (AF), two of the main regions in the IVD. However, few studies have focused on the AF-NP interface (transition zone; TZ). Therefore, the current study aims to, for the first time, characterize the cyclic and failure mechanical properties of the TZ region under physiological loading (1, 3, and 5%s^-1 strain rates) and investigate the structural integration mechanisms between the NP, TZ, and AF regions. The results of the current study reveal significant effects of region (NP, TZ, and AF) and strain rates (1, 3, and 5%s^-1) on stiffness (p < 0.001). In addition, energy absorption is significantly higher for the AF compared to the TZ and NP (p <0.001) as well as between the TZ and NP (p <0.001). The current research finds adaptation, direct penetration, and entanglement between TZ and AF fibers as three common mechanisms for structural integration between the TZ and AF regions. STATEMENT OF SIGNIFICANCE: Despite a large number of studies that have mechanically, structurally, and biologically characterized the nucleus pulposus (NP) and annulus fibrosus (AF) regions, few studies have focused on the NP-AF interface region (known as Transition Zone; TZ) in the IVD; hence, our understanding of the TZ structure-function relationship is still incomplete. Of particular importance, the cyclic mechanical properties of the TZ, compared to the adjacent regions (NP and AF), are yet to be explored and the precise nature of the structural integration between the NP and AF via the TZ region is not yet known. The current study explores both the mechanical and structural properties of the TZ region to ultimately identify the mechanism of integration between the NP and AF.

Raloxifene retards the progression of adjacent segmental intervertebral disc degeneration by inhibiting apoptosis of nucleus pulposus in ovariectomized rats

BACKGROUND

Adjacent segmental intervertebral disk degeneration (ASDD) is a major complication secondary to lumbar fusion. Although ASSD pathogenesis remains unclear, the primary cause of intervertebral disk degeneration (IVDD) development is apoptosis of nucleus pulposus (NP). Raloxifene (RAL) could delay ASDD by inhibiting NP apoptosis.

METHODS

An ASDD rat model was established by ovariectomy (OVX) and posterolateral spinal fusion (PLF) on levels 4-5 of the lumbar vertebrae. Rats in the treatment groups were administered 1 mg/kg/d RAL by gavage for 12 weeks, following which, all animals were euthanized. Lumbar fusion, apoptosis, ASDD, and vertebrae micro-architecture were evaluated.

RESULTS

RAL maintained intervertebral disk height (DHI), delayed vertebral osteoporosis, reduced histological score, and inhibited apoptosis. The OVX+PLF+RAL group revealed upregulated expression of aggrecan and B-cell lymphoma-2 (bcl2), as well as significantly downregulated expression of a disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS-4), metalloproteinase-13 (MMP-13), caspase-3, BCL2-associated X (bax), and transferase dUTP nick end labeling (TUNEL) staining. Micro-computed tomography (Micro-CT) analysis revealed higher bone volume fraction (BV/TV), bone mineral density (BMD), and trabecular number (Tb.N), and lower trabecular separation (Tb.Sp) in OVX+PLF+RAL group than in the OVX+PLF group.

CONCLUSIONS

RAL can postpone ASDD development in OVX rats through inhibiting extracellular matrix metabolic imbalance, NP cell apoptosis, and vertebral osteoporosis. These findings showed RAL as a potential therapeutic target for ASDD.

The ultrastructural organization of elastic fibers at the interface of the nucleus and annulus of the intervertebral disk

There has been no study to describe the ultrastructural organization of elastic fibers at the interface of the nucleus pulposus and annulus fibrosus of the intervertebral disk (IVD), a region called the transition zone (TZ). A previously developed digestion technique was optimized to eliminate cells and non-elastin ECM components except for the elastic fibers from the anterolateral (AL) and posterolateral (PL) regions of the TZ in ovine IVDs. Not previously reported, the current study identified a complex elastic fiber network across the TZ for both AL and PL regions. In the AL region, this network consisted of major thick elastic fibers (≈ 1 µm) that were interconnected with delicate (< 200 nm) elastic fibers. While the same ultrastructural organization was observed in the PL region, interestingly the size of the elastic fibers was smaller (< 100 nm) compared to those that were located in the AL region. Quantitative analysis of the elastic fibers revealed significant differences in the size (p < 0.001) and the orientation of elastic fibers (p = 0.001) between the AL and PL regions, with a higher orientation and larger size of elastic fibers observed in the AL region. The gradual elimination of cells and non-elastin extracellular matrix components identified that elastic fibers in the TZ region in combination with the extracellular matrix created a honeycomb structure that was more compact at the AF interface compared to that located close to the NP. Three different symmetrically organized angles of rotation (0⁰ and ±90⁰) were detected for the honeycomb structure at both interfaces, and the structure was significantly orientated at the TZ-AF compared to the TZ-NP interface (p = 0.003).

Elastic fibers: The missing key to improve engineering concepts for reconstruction of the Nucleus Pulposus in the intervertebral disc

The increasing prevalence of low back pain has imposed a heavy economic burden on global healthcare systems. Intense research activities have been performed for the regeneration of the Nucleus Pulposus (NP) of the IVD; however, tissue-engineered scaffolds have failed to capture the multi-scale structural hierarchy of the native tissue. The current study revealed for the first time, that elastic fibers form a network across the NP consisting of straight and thick parallel fibers that were interconnected by wavy fine fibers and strands. Both straight fibers and twisted strands were regularly merged or branched to form a fine elastic network across the NP. As a key structural feature, ultrathin (53 ± 7 nm), thin (215 ± 20 nm), and thick (890 ± 12 nm) elastic fibers were observed in the NP. While our quantitative analysis for measurement of the thickness of elastic fibers revealed no significant differences (p < 0.633), the preferential orientation of fibers was found to be significantly different (p < 0.001) across the NP. The distribution of orientation for the elastic fibers in the NP represented one major organized angle of orientation except for the central NP. We found that the distribution of elastic fibers in the central NP was different from those located in the peripheral regions representing two symmetrically organized major peaks (±45⁰). No significant differences in the maximum fiber count at the major angles of orientation (±45⁰) were observed for both peripheral (p = 0.427) and central NP (p = 0.788). Based on these new findings a structural model for the elastic fibers in the NP was proposed. The geometrical presentation, along with the distribution of elastic fibers orientation, resulting from the present study identifies the ultrastructural organization of elastic fibers in the NP important towards understanding their mechanical role which is still under investigation. Given the results of this new geometrical analysis, more-accurate multiscale finite element models can now be developed, which will provide new insights into the mechanobiology of the IVD. In addition, the results of this study can potentially be used for the fabrication of bio-inspired tissue-engineered scaffolds and IVD models to truly capture the multi-scale structural hierarchy of IVDs. STATEMENT OF SIGNIFICANCE: Visualization of elastic fibers in the nucleus of the intervertebral disk under high magnification was not reported before. The present research utilized extracellular matrix partial digestion to address significant gaps in understanding of nucleus microstructure that can potentially be used for the fabrication of bio-inspired tissue-engineered scaffolds and disk models to truly capture the multi-scale structural hierarchy of discs.

Lumbar spinal ligament characteristics extracted from stepwise reduction experiments allow for preciser modeling than literature data

Lumbar ligaments play a key role in stabilizing the spine, particularly assisting muscles at wide-range movements. Hence, valid ligament force–strain data are required to generate physiological model predictions. These data have been obtained by experiments on single ligaments or functional units throughout the literature. However, contrary to detailed spine geometries, gained, for instance, from CT data, ligament characteristics are often inattentively transferred to multi-body system (MBS) or finite element models. In this paper, we use an elaborated MBS model of the lumbar spine to demonstrate how individualized ligament characteristics can be obtained by reversely reenacting stepwise reduction experiments, where the range of motion (ROM) was measured. We additionally validated the extracted characteristics with physiological experiments on intradiscal pressure (IDP). Our results on a total of in each case 160 ROM and 49 IDP simulations indicated superiority of our procedure (seven and eight outliers) toward the incorporation of classical literature data (on average 71 and 31 outliers).

Creep experimental study on the lumbar intervertebral disk under vibration compression load

The intervertebral disk cushions the load generated by human activity and absorbs energy to keep the spine moving steadily. Vibration condition is one of the important causes of disk degeneration. Creep experiments using the sheep lumbar intervertebral disk were carried out under vibration compression. Regularities of the strain of the disk with time were obtained and compared with those of static load. The influence of vibration frequency and time on the creep properties of the intervertebral disk was analyzed. An intervertebral disk three-parameter solid creep constitutive model considering vibration factors was established and the parameters in the model were identified. The results show that the strain of the lumbar intervertebral disk exhibits an exponential relationship with time and is unrelated to static compression or vibration load. Under the same vibration amplitude, the creep increases with vibration frequency and the relationship between them is nonlinear. The vibration frequency has a significant effect on the strain. The creep rate decreases gradually with time and is obviously influenced by vibration frequency at low vibration amplitudes. The creep prediction results obtained using the constitutive model with the time-varying material parameters are in good agreement with the experimental results. The two elastic moduli in the model decrease with time and the viscosity coefficient increases with time.

Evaluation of Dimensions of Kambin's Triangle to Calculate Maximum Permissible Cannula Diameter for Percutaneous Endoscopic Lumbar Discectomy : A 3-Dimensional Magnetic Resonance Imaging Based Study

Objective

To evaluate 3-dimensional magnetic resonance imaging (MRI) of Kambin’s safe zone to calculate maximum cannula diameter permissible for safe percutaneous endoscopic lumbar discectomy.

Methods

Fifty 3D MRIs of 19 males and 31 females (mean, 47 years) were analysed. Oblique, axial and sagittal views were used for image analysis. Three authors calculated the inscribed circle (cannula diameter) individually, within the neural (original) and bony Kambin’s triangle in oblique views, disc heights on sagittal views and root to facet distances at upper and lower end plate levels on axial views and their averages were taken.

Results

The mean root to facet distances at upper end plate level measured on axial sections increased from 3.42±3.01 mm at L12 level to 4.57±2.49 mm at L5S1 level. The mean root to facet distances at lower end plate level measured on axial sections also increased from 6.07±1.13 mm at L12 level to 12.9±2.83 mm at L5S1 level. Mean maximum cannula diameter permissible through the neural Kambin’s triangle increased from 5.67±1.38 mm at L12 level to 9.7±3.82 mm at L5S1 level. The mean maximum cannula diameter permissible through the bony Kambin’s triangle also increased from 4.03±1.08 mm at L12 level to 6.11±1 mm at L5S1 level. Only 2% of the 427 bony Kambin’s triangles could accommodate a cannula diameter of 8mm. The base of the bony Kambin’s triangle taken in oblique view (3D MRI) was significantly higher than the root to facet distance at lower end plate level taken in axial view.

Conclusion

The largest mean diameter of endoscopic cannula passable through “bony” Kambin’s triangle was distinctively smaller than the largest mean diameter of endoscopic cannula passable through “neural” Kambin’s triangle at all levels. Although proximity of exiting root to the facet joint is always taken into consideration before PELD procedure, our 3D MRI based anatomical study is the first to provide actual maximum cannula dimensions permissible in this region.

Diffusion based MR measurements correlates with age-related changes in human intervertebral disks

BACKGROUND

Understanding the association between MR parameters and age related deterioration in human intervertebral disks forms an important step in the development of clinical diagnostic protocols for disk disease.

METHODS

Ten unfixed thoracic and lumbar cadaver disk joints, age 37-81 years were imaged at 9.4 T using T2 relaxation (CPMG) and ADC (DWI spin echo) MR protocols. For each MR parameter, spatial maps were computed from the axial images, with the AF and NP segmented based on the T2 maps. Linear regression tested for the correlation between mean and variance (COV) of T2 and ADC with age in the disk, nucleus and annulus, and the effect of thoracic vs. lumbar spine on these correlations.

FINDINGS

In the disk, age negatively correlated with mean ADC (P < 0.001) and positively with COV of ADC (P < 0.001) and T2 (P < 0.05). Age was negatively correlated with mean T2 (P < 0.01), mean ADC (P < 0.001) and positively with COV of ADC (P < 0.001) and T2 (P < 0.05) in the NP and positively correlated with mean T2 (P < 0.05), COV of ADC (P < 0.01) and T2 (P < 0.05) and negatively with mean ADC (P < 0.05) in the AF. Compared to thoracic disks, lumbar disks showed higher mean ADC (P < 0.05), lower mean T2 (P < 0.001) and higher COV of ADC (P < 0.01) and T2 (P < 0.05).

INTERPRETATION

Compared to T2, MR diffusion was a more sensitive measure of age mediated changes in disk tissues. Strong differences in the association of MR parameters with age between the lumbar and thoracic suggest that mechanical environment effects tissue specific MR parameters' association with age.

A 3-Dimensional Finite Element Analysis of Adjacent Segment Disk Degeneration Induced by Transforaminal Lumbar Interbody Fusion After Pedicle Screw Fixation

BACKGROUND

Transforaminal lumbar interbody fusion (TLIF) is an effective treatment of upper lumbar intervertebral disk herniation. However, its clinical efficacy for adjacent segment disk degeneration (ASDD) remains undefined. Therefore, the biomechanical evaluation of ASDD caused by TLIF after pedicle screw fixation (PSF) was explored via a 3-dimensional (3D) finite element analysis.

METHODS

Computed tomography images of a healthy male adult volunteer were used in this study. A L3-4 3D finite element model (model) was successfully constructed using Pro/E software, which was also used to establish the L4-5 of the TLIF, PSF, and PSF + TLIF models. Under the same loading conditions, the protrusion and retraction of the adjacent intervertebral disk and the stress distribution of the annulus fibrosis, facet joint, and articular process in the TLIF, PSF, and PSF + TLIF models were all compared.

RESULTS

Protrusion and retraction of the adjacent intervertebral disk were more notable in the PSF + TLIF model than in the PSF model under the same loading conditions. The stress of the annulus fibrosis of the PSF + TLIF model was stronger relative to that of the PSF model under flexion, extension, or lateral bending. The stress of the articular process of the PSF + TLIF model was also stronger than that of the PSF model under extension or lateral bending.

CONCLUSIONS

This study provides evidence that TLIF may aggravate ASDD after PSF. Furthermore, the findings provided in this report represent the theoretic basis for the clinical analysis of ASDD caused by TLIF after PSF.

Axial loading during MRI reveals deviant characteristics within posterior IVD regions between low back pain patients and controls

PURPOSE

To investigate differences in functional intervertebral disk (IVD) characteristics between low back pain (LBP) patients and controls using T2-mapping with axial loading during MRI (alMRI).

METHODS

In total, 120 IVDs in 24 LBP patients (mean age 39 years, range 25-69) were examined with T2-mapping without loading of the spine (uMRI) and with alMRI (DynaWell^® loading device) and compared with 60 IVDs in 12 controls (mean age 38 years, range 25-63). The IVD T2-value was acquired after 20-min loading in five regions of interests (ROI), ROI1-5 from anterior to posterior. T2-values were compared between loading states and cohorts with adjustment for Pfirrmann grade.

RESULTS

In LBP patients, mean T2-value of the entire IVD was 64 ms for uMRI and 66 ms for alMRI (p = 0.03) and, in controls, 65 ms and 65 ms (p = 0.5). Load-induced T2-differences (alMRI-uMRI) were seen in all ROIs in both patients (0.001 > p < 0.005) and controls (0.0001 > p < 0.03). In patients, alMRI induced an increase in T2-value for ROI1-3 (23%, 18% and 5%) and a decrease for ROI4 (3%) and ROI5 (24%). More pronounced load-induced decrease was detected in ROI4 in controls (9%/p = 0.03), while a higher absolute T2-value was found for ROI5 during alMRI in patients (38 ms) compared to controls (33 ms) (p = 0.04).

CONCLUSION

The alMRI-induced differences in T2-value in ROI4 and ROI5 between patients and controls most probably indicate biomechanical impairment in the posterior IVD regions. Hence, alMRI combined with T2-mapping offers an objective and clinical feasible tool for biomechanical IVD characterization that may deepen the knowledge regarding how LBP is related to altered IVD matrix composition. These slides can be retrieved under Electronic Supplementary Material.

In vitro efficacy of silk sericin microparticles and platelet lysate for intervertebral disk regeneration

Intervertebral disk degeneration is an oxidative and inflammatory pathological condition that induces viability and functionality reduction of Nucleus Pulposus cells (NPs). Cellular therapies were previously proposed to repair and substitute the herniated disk but low proliferative index and pathological conditions of NPs dramatically reduced the efficacy of this approach. To overcome these problems we proposed, for the first time, a therapeutic system based on the association of silk sericin microparticles and platelet-derived products. Silk sericin (SS) is a bioactive protein with marked antioxidant properties, while platelet lysate (PL) and platelet poor plasma (PPP) represent a source of growth factors able to support cell viability and to promote tissue regeneration. We demonstrated that the mixture PL + PPP promoted NPs proliferation with a significant reduction of cellular doubling time. SS microparticles, alone or in combination with PPP, presented the higher ROS-scavenging activity while, SS microparticles and PL resulted as the best association able to protect NPs against oxidative stress induce by hydroxide peroxide. Based on these results, the authors are confident that, with the ever increasing need of efficacious tools for regenerative medicine purposes, SS microparticles and PL + PPP association could represent an effective approach for the development of low impact and non-invasive therapies.

[High mechanical stretch stress promotes degeneration of the human nucleus pulposus cells through NF-κb signaling pathway]

Objective: To investigate the effect of high mechanical stretch stress(HMS)on human nucleus pulposus cells and its regulatory mechanism. Methods: The non-degenerated nucleus pulposus tissue (Pfirrmann<grade Ⅲ) removed from the patient's surgery was harvested and the human nucleus pulposus cells were isolated and cultured. In the presence or absence of pretreatment with the NF-κB specific blocker Bay11-7082, the cultured human nucleus pulposus cells were loaded cyclic mechanical stretch stress(CMS) with different parameters using the Flexercell system.The cell culture medium was collected and the secretion of inflammatory cytokines was detected by Elisa. The nucleus pulposus cells loaded with cyclic mechanical stretch stress(CMS) was collected, the changes of NF-κB/P65 signal pathway were detected, The mRNA and protein levels' expression changes were detected by RT-PCR and WB; after human nucleus pulposus cells were exposed to IL-1β, with or without Bay11-7082, the changes of P65 were detected by immunofluorescence. Results: Those mechanical stretch stress of high amplitude (9%, 19%), low frequency (0.01 Hz) and long duration (72 h) led to degeneration of human nucleus pulposus cells, while the mechanical stretch stress of low amplitude (3%), low frequency and long duration could not promote the degeneration process; the mechanical stretch stress of high amplitude(19%), low-frequency(0.01 Hz) could promote the release of inflammatory cytokines of human nucleus pulposus cells after 24 h duration; high-amplitude, low-frequency mechanical stretch stress could activate the NF-κB signaling pathway in human nucleus pulposus cells, Bay11-7082 could block the process; immunofluorescence showed that IL-1β could promote the phosphorylation of P65 in the cytoplasm of human nucleus pulposus cells and promote the entry of P65 into the cell nucleus process, Bay11-7082 could block those processes; Bay11-7082, the specific blocking agent of NF-κB signaling pathway, could block the degeneration process of human nucleus pulposus cells induced by high cyclic mechanical stretch stress(CMS) in a dose-dependent. Conclusions: High cyclic mechanical stretch stress promotes human nucleus pulposus cells degeneration through NF-κB signaling pathway.

A Murine Model for Human ECO Syndrome Reveals a Critical Role of Intestinal Cell Kinase in Skeletal Development

An autosomal-recessive inactivating mutation R272Q in the human intestinal cell kinase (ICK) gene caused profound multiplex developmental defects in human endocrine-cerebro-osteodysplasia (ECO) syndrome. ECO patients exhibited a wide variety of skeletal abnormalities, yet the underlying mechanisms by which ICK regulates skeletal development remained largely unknown. The goal of this study was to understand the structural and mechanistic basis underlying skeletal anomalies caused by ICK dysfunction. Ick R272Q knock-in transgenic mouse model not only recapitulated major ECO skeletal defects such as short limbs and polydactyly but also revealed a deformed spine with defective intervertebral disk. Loss of ICK function markedly reduced mineralization in the spinal column, ribs, and long bones. Ick mutants showed a significant decrease in the proliferation zone of long bones and the number of type X collagen-expressing hypertrophic chondrocytes in the spinal column and the growth plate of long bones. These results implicate that ICK plays an important role in bone and cartilage development by promoting chondrocyte proliferation and maturation. Our findings provided new mechanistic insights into the skeletal phenotype of human ECO and ECO-like syndromes.

Correlation among Inflammatory Cytokine Expression Levels, Degree of Disk Degeneration, and Predominant Clinical Symptoms in Patients with Degenerated Intervertebral Discs

Study Design

Observational study.

Purpose

To assess the correlation among inflammatory cytokine expression levels, degree of intervertebral disk (IVD) degeneration, and predominant clinical symptoms observed in degenerative disk disease (DDD).

Overview of Literature

Low back pain (LBP) is associated with inflammatory cytokine expression levels, including those of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), and nerve growth factor (NGF). However, the association between cytokine expression levels and the physiological mechanisms of disk degeneration and clinical pain remain controversial.

Methods

Using the enzyme-linked immunosorbent assay, TNF-α, IL-6, and NGF expression levels were analyzed in 58 IVD samples that were harvested from patients with lumbar DDD. Patient samples were grouped according to the degree of IVD degeneration using the Pfirrmann grading system and magnetic resonance imaging, and the correlations between the disease groups and each cytokine expression level were assessed. In addition, on the basis of their predominant preoperative symptoms, the patients were assigned to either an LBP or leg pain group to determine the correlation among these disease manifestations and individual cytokine expression levels.

Results

A gradual increase in TNF-α (R=0.391) and IL-6 (R=0.388) expression levels correlated with the degree of IVD degeneration, whereas NGF (R=0.164) expression levels exhibited a minimal decrease with disease progression. Regarding the predominant clinical manifestation, only the LBP group exhibited a significant increase in TNF-α expression levels (p=0.002).

Conclusions

These results suggested that TNF-α and IL-6 play an important role in the pathophysiology of IVD degeneration at any stage, whereas NGF plays an important role during the early disease stages. Moreover, because TNF-α expression levels were significantly high in the LBP group, we propose that they are involved in LBP onset or progression.

[Posterior debridement, interbody fusion, internal fixation for treatment of lumbar discitis]

OBJECTIVE

To evaluate the clinical effects of posterior debridement, interbody fusion with internal fixation in the treatment of lumbar discitis.

METHODS

The clinical data of 13 patients with lumbar discitis treated from January 2005 to June 2012 was retrospectively analyzed. There were 9 males and 4 females, aged from 31 to 68 years old with an average of 56 years old. There were 2 cases on L3, 4, 4 cases on L4, 5, and 7 cases on L5S1. Two cases complicated with diabetes, 4 cases with hypertension, and 1 case with obsolete pulmonary tuberculosis. ESR level of 13 cases was 12-89 mm/h with an average of 42 mm/h; and C reactive protein fluctuations level was level 8-114 ng/L with an average of 47 ng/L. All the patients denied history of operation or injection, and the main symptom was severe pain and limitation of motion in lumbar, with no efficacy for conservative methods. Preoperative VAS was from 5 to 10 points with an average of 7.8 points. All patients were treated with posterior debridement, interbody fusion, and internal fixation.

RESULTS

All the patients left hospital after wound healing, and the effective antibiotics were continuously used for 4 weeks intravenously and 2 weeks for orally. All patients were followed up from 7 to 24 months with an average of 18 months. VAS decreased for 0-1 point. No internal fixation breakage, and recurrence were found. Bone graft got fusion, and postoperative pathology showed phlogistic changes.

CONCLUSIONS

One-stage posterior debridement, interbody fusion with internal fixation was an effective method in treating lumbar discitis, and it lead to quicker relived pain relief and earlier mobilization.

Intervertebral Disk Degeneration and Repair

Intervertebral disk (IVD) degeneration is a natural progression of the aging process. Degenerative disk disease (DDD) is a pathologic condition associated with IVD that has been associated with chronic back pain. There are a variety of different mechanisms of DDD (genetic, mechanical, exposure). Each of these pathways leads to a final common result of unbalancing the anabolic and catabolic environment of the extracellular matrix in favor of catabolism. Attempts have been made to gain an understanding of the process of IVD degeneration with in Vitro studies. These models help our understanding of the disease process, but are limited as they do not come close to replicating the complexities that exist with an in Vivo model. Animal models have been developed to help us gain further understanding of the degenerative cascade of IVD degeneration In Vivo and test experimental treatment modalities to either prevent or reverse the process of DDD. Many modalities for treatment of DDD have been developed including therapeutic protein injections, stem cell injections, gene therapy, and tissue engineering. These interventions have had promising outcomes in animal models. Several of these modalities have been attempted in human trials, with early outcomes having promising results. Further, increasing our understanding of the degenerative process is essential to the development of new therapeutic interventions and the optimization of existing treatment protocols. Despite limited data, biological therapies are a promising treatment modality for DDD that could impact our future management of low back pain.

Influence of mononuclear cell therapy on disc degeneration in rabbits

OBJECTIVE

The objective of this research was to evaluate the influence of autologous mononuclear stem cells injections on histological changes of collagen in the fibrous annulus of the intervertebral disk after experimental injury.

METHODS

32 New Zealand rabbits were submitted to intervertebral disk puncture, followed by intradiscal injection of mononuclear cells from the iliac crest versus saline injection in the following time periods: two months after the injury (SC2M and SS2M), two weeks (SC2W and SS2W) immediately after injury (SCCP and SSCP), and without inducing degeneration (SCSP and SSSP). Two months after cell therapy, the animals were euthanized and collagen changes in the intervertebral discs were histologically evaluated.

RESULTS

There were significant differences in ELAF between SS2W and SS2S groups (p = 0.018). This difference was due to an increase in type I collagen in SS2W group (56.7%) compared to SC2S (13.28%).

CONCLUSION

Treatment with mononuclear mesenchymal stem cells reduced changes in the type I and III collagen distribution in rabbits AF degenerated discs up to two weeks after the induction of degeneration.

Experimental Model of Intervertebral Disk Mediated Postoperative Epidural Fibrosis

BACKGROUND

Postoperative epidural fibrosis (EF) after lumbar discectomy is the most common and at the same time controversial issue.

PURPOSE

The etiology and pathogenesis creates a lot of discussion and selection of methods of treatment and prevention continues.

METHODS

LIV laminectomy with dura mater (DM) exposition was done in 24 rats, and then, 0.3 ml of elements of suspension of autologous intervertebral disk was implicated on DM. As autologous intervertebral disk, we used the intervertebral disk from amputated tail. In all the animals, incisions were closed with 3/0 Vicryl. EF was examined. Fibroblast cell density was calculated in each field at ×40 magnification: Grade 1 - fewer than 100 fibroblasts in each field; Grade 2 - 100-150 fibroblasts in each field; Grade 3 - more than 150 fibroblasts in each field.

RESULTS

Based on histological results, we confirmed our model of experiment. On the 30th day of evaluation, there were significant histological evidences of postoperative epidural adhesions in experimental animals, which included the obliteration of epidural space, the presence of adhesions in the dura and nerve roots, the restructuring of the yellow ligament, bone sclerosis, excessive appearance of fibrous tissue around the autologous intervertebral disk tissue that applied on the DM.

CONCLUSION

In our work, we describe a new experimental model, where the elements of autologous intervertebral disk play the role of inflammation trigger, which cause postoperative scar and EF.

Importance of IL-6, MMP-1, IGF-1, and BAX Levels in Lumbar Herniated Disks and Posterior Longitudinal Ligament in Patients with Sciatic Pain

PURPOSE

The aim of this study was to evaluate prognostic importance of interleukin-6 (IL-6), matrix metalloproteinase (MMP)-1, insulin-like growth factor (IGF)-1, and Bcl-2-associated X protein (BAX) levels in biopsy specimens taken from the intervertebral disk specimens and the posterior longitudinal ligaments of patients with sciatic pain.

METHODS

The specimens of the intervertebral disk and the posterior longitudinal ligament were obtained from 52 patients undergoing herniectomy and diskectomy at the Neurosurgery Department of the Abant Izzet Baysal University Izzet Baysal Training and Research Hospital between April 2012 and February 2014. The immunohistochemical expressions of IL-6, MMP-1, IGF-1, and BAX were evaluated in three categories: mild, moderate, and intense.

RESULTS

The IL-6 expression in the intervertebral disk specimens was intense in the sequestration group when compared with that of the "protrusion" and "extrusion" groups. The intervertebral disk specimens in "extrusion" and "sequestration" groups were stained intensely for MMP-1. The IGF-1 expression was stained intensely in the intervertebral disk tissue of the extrude group patients. For the "extrusion" and "sequestration" groups, the intervertebral disk specimens were stained intensely for BAX compared with the protrude group. The IL-6 expression in the posterior longitudinal ligament specimens was more intense in the "sequestration" and "extrusion" groups when compared with that of the protrude group. The MMP-1 expressions were milder in the sequestration group when compared with that of the "extrusion" and "protrusion" groups.

CONCLUSIONS

Our findings suggest that the cytokines, enzymes, growth factors, and proapoptotic proteins, such as IL-6, MMP-1, IGF-1, and BAX, may be critical factors in the pathophysiology of the degeneration of the intervertebral disks in patients with symptomatic degenerative disk disease.

Osteoclast activators are elevated in intervertebral disks with Modic changes among patients operated for herniated nucleus pulposus

PURPOSE

Modic changes (MC) are associated with low back pain (LBP). Inflammation is considered as a key factor that triggers symptoms in especially type I MC, but so far of the potential inflammatory candidates only TNFα has been linked to MC. The objective of the study was to analyze a set of inflammatory mediators in human surgical disk samples and quantify their association with MC in the adjacent vertebral bodies.

METHODS

The study sample consisted of 51 intervertebral disk tissue specimens; 20 'No MC' disks, 19 'Type I MC' disks, and 12 'Type II MC' disks. mRNA expression of 46 cytokines was quantified from isolated RNA. Tissue samples were stained using hematoxylin and eosin, toluidine blue, Herovici, CD68 and CD163.

RESULTS

No significant differences were found in the amount of macrophages or presence of chondrocyte conglomerates between the MC groups. Of the multiple genes tested, statistically significant associations were observed for M-CSF1 (p = 0.028), RANKL (p = 0.035), RUNX1 (p = 0.032), and RUNX2 (p = 0.047) that were increased in 'Type II MC,' while OSCAR (p = 0.042) was increased in 'Type I MC' group compared to 'No MC.'

CONCLUSIONS

Since these cytokines are related to differentiation and proliferation of osteoclasts, our data suggest that the stimulation of vertebral osteoclasts by factors secreted by disk tissue is involved in the pathophysiology of MC.

The degenerative state of the intervertebral disk independently predicts the failure of human lumbar spine to high rate loading: an experimental study

BACKGROUND

In the elderly, 30%-50% of patients report a fall event to precede the onset of vertebral fractures. The dynamic characteristics of the spine determine the peak forces on the vertebrae in a fall. However, we know little about the effect of intervertebral disk degeneration on the failure of human spines under the high loading rates associated with such falls. We hypothesized that MR estimates of disk hydration and viscoelastic properties will provide better estimates of failure strength than bone density alone.

METHODS

Seventeen L1-L3 human spine segments were imaged (magnetic resonance imaging, dual-energy X-ray absorptiometry), their dynamic responses quantified using pendulum based impact, and the spines tested to failure under high rate loading simulating a fall event. The spines' stiffness and damping constants were computed (Kelvin-Voigt model) with disk hydration and geometry assessed from T2 and proton density images.

FINDINGS

Under impact, the spines exhibited a second-order underdamped response with stiffness and damping ranging (17.9-754.5) kN/m and (133.6-905.3) Ns/m respectively. Damping, but not stiffness, was negatively correlated with higher ultimate strength (P<0.05). Higher bone mineral density and MR-estimated disk hydration correlated with higher ultimate strength (P<0.01 for both). No such correlations were observed for the T2 values. Adding disk hydration yielded a 20% increase in the model's association with failure load compared to bone density alone (MANOVA, P<0.001).

INTERPRETATION

The strong correlation between disk viscoelastic properties and MR-estimated hydration with the spine segments' ultimate strength clearly demonstrates the need to include disk degeneration as part of fracture risk assessment in the elderly spine.

Finite element simulation of an artificial intervertebral disk using fiber reinforced laminated composite model

Degeneration of intervertebral disk (IVD) has been increased in recent years. The lumbar herniation can be cured using conservative and surgical procedures. Surgery is considered after failure of conservative treatment. Partial discectomy, fusion, and total disk replacement (TDR) are also common surgical treatments for degenerative disk disease. However, due to limitations and disadvantages of the current treatments, many studies have been carried out to approach the best design of mimicking natural disk. Recently, a new method of TDRs has been introduced using nature deformation of IVD by reinforced fibers of annulus fibrosis. Nonetheless, owing to limitations of experimental works on the human body, numerical studies of IVD may help to understand load transfer and biomechanical properties within the disks with reinforced fibers. In this study, a three-dimensional (3D) finite element model of the L2-L3 disk vertebrae unit with 12 vertical fibers embedded into annulus fibrosis was constructed. The IVD was subjected to compressive force, bending moment, and axial torsion. The most important parameters of disk failures were compared to that of experimental data. The results showed that the addition of reinforced fibers into the disk invokes a significant decrease of stress in the nucleus and annulus. The findings of this study may have implications not only for developing IVDs with reinforced fibers but also for the application of fiber reinforced IVD in orthopedics surgeries as a suitable implant.

Finite element modeling of soft tissues: material models, tissue interaction and challenges

BACKGROUND

Musculoskeletal soft tissues, such as articular cartilage, ligaments, knee meniscus and intervertebral disk, have a complex structure, which provides elasticity and capability to support and distribute the body loads. Soft tissues describe an inhomogeneous and multiphasic structure, and exhibit a nonlinear, time-dependent behavior. Their mechanical response is governed by a substance composed of protein fiber-rich and proteoglycan-rich extracellular matrix and interstitial fluid. Protein fibers (e.g. collagen) give the tissue direction dependent stiffness and strength. To investigate these complex biological systems, the use of mathematical tools is well established, alone or in combination with experimental in vitro and in vivo tests. However, the development of these models poses many challenges due to the complex structure and mechanical response of soft tissues.

METHODS

Non-systematic literature review.

FINDINGS

This paper provides a summary of different modeling strategies with associated material properties, contact interactions between articulating tissues, validation and sensitivity of soft tissues with special focus on knee joint soft tissues and intervertebral disk. Furthermore, it reviews and discusses some salient clinical findings of reported finite element simulations.

INTERPRETATION

Model studies extensively contributed to the understanding of functional biomechanics of soft tissues. Models can be effectively used to elucidate clinically relevant questions. However, users should be aware of the complexity of such tissues and of the capabilities and limitations of these approaches to adequately simulate a specific in vivo or in vitro phenomenon.

New technical tip for anterior cervical plating : make hole first and choose the proper plate size later

OBJECTIVE

It is well known that plate-to-disc distance (PDD) is closely related to adjacent-level ossification following anterior cervical plate placement. The study was undertaken to compare the outcomes of two different anterior cervical plating methods for degenerative cervical condition. Specifically, the new method involves making holes for plate screws first with an air drill and then choosing a plate size. The other method was standard, that is, decide on the plate size first, locate the plate on the anterior vertebral body, and then drilling the screw holes. Our null hypothesis was that the new technical tip may increase PDD as compared with the standard anterior cervical plating procedure.

METHODS

We retrospectively reviewed 49 patients who had a solid fusion after anterior cervical arthrodesis with a plate for the treatment of cervical disc degeneration. Twenty-three patients underwent the new anterior cervical plating technique (Group A) and 26 patients underwent the standard technique (Group B). PDD and ratios between PDD to anterior body heights (ABH) were measured using postoperative lateral radiographs. In addition, operating times and clinical results were reviewed in all cases.

RESULTS

The mean durations of follow-up were 16.42±5.99 (Group A) and 19.83±6.71 (Group B) months, range 12 to 35 months. Of these parameters mentioned above, cephalad PDD (5.43 versus 3.46 mm, p=0.005) and cephalad PDD/ABH (0.36 versus 0.23, p=0.004) were significantly greater in the Group A, whereas operation time for two segment arthrodesis (141.9 versus 170.6 minutes, p=0.047) was significantly lower in the Group A. There were no significant difference between the two groups in caudal PDD (5.92 versus 5.06 mm), caudal PDD/ABH (0.37 versus 0.32) and clinical results.

CONCLUSION

The new anterior cervical plating method represents an improvement over the standard method in terms of cephalad plate-to-disc distance and operating time.

RADIOLOGICAL ANALYSIS OF EXPERIMENTAL DISC DEGENERATION IN RABBITS

OBJECTIVE

To validate radiographic evaluation of a rabbit model for disc degeneration.

METHODS

Lumbar intervertebral discs of New Zealand rabbits were stabbed three times with a 18G needle at a limited depth of 5mm, through lateral approach. Serial radiographic images were taken on the early pre-and postoperative periods, and after four, eight and 12 weeks of the procedure, with subsequent analysis of disc height, osteophyte formation, endplate sclerosis, and presence of disc degeneration. The statistical analysis of data was validated by the Kappa coefficient, with a confidence interval (CI) of 95%.

RESULTS

A significant reduction of disc space was found on AP X-ray images after 12 postoperative weeks, with Kappa = 0.489 for CI 95% (0.25-0.72) with p < 0.001. X-ray signs of disc degeneration also presented Kappa = 0.63 for CI 95% (0.39-0.86) with p < 0.001. The remaining assessed criteria showed positive results, but with a lower Kappa value.

CONCLUSION

The disc degeneration model using rabbits as proposed in this study was shown to be feasible, with positive X-ray correlation between pre- and postoperative images, validating the potential to induce disc degeneration in this animal model for future studies.