Kuo Yuan Huang

Biomechanical analysis of the lumbar spine on facet joint force and intradiscal pressure - a finite element study

BackgroundFinite element analysis results will show significant differences if the model used is performed under various material properties, geometries, loading modes or other conditions. This study adopted an FE model, taking into account the possible asymmetry inherently existing in the spine with respect to the sagittal plane, with a more geometrically realistic outline to analyze and compare the biomechanical behaviour of the lumbar spine with regard to the facet force and intradiscal pressure, which are associated with low back pain symptoms and other spinal disorders. Dealing carefully with the contact surfaces of the facet joints at various levels of the lumbar spine can potentially help us further ascertain physiological behaviour concerning the frictional effects of facet joints under separate loadings or the responses to the compressive loads in the discs.MethodsA lumbar spine model was constructed from processes including smoothing the bony outline of each scan image, stacking the boundary lines into a smooth surface model, and subsequent further processing in order to conform with the purpose of effective finite element analysis performance. For simplicity, most spinal components were modelled as isotropic and linear materials with the exception of spinal ligaments (bilinear). The contact behaviour of the facet joints and changes of the intradiscal pressure with different postures were analyzed.ResultsThe results revealed that asymmetric responses of the facet joint forces exist in various postures and that such effect is amplified with larger loadings. In axial rotation, the facet joint forces were relatively larger in the contralateral facet joints than in the ipsilateral ones at the same level. Although the effect of the preloads on facet joint forces was not apparent, intradiscal pressure did increase with preload, and its magnitude increased more markedly in flexion than in extension and axial rotation.ConclusionsDisc pressures showed a significant increase with preload and changed more noticeably in flexion than in extension or in axial rotation. Compared with the applied preloads, the postures played a more important role, especially in axial rotation; the facet joint forces were increased in the contralateral facet joints as compared to the ipsilateral ones at the same level of the lumbar spine.

The in vivo biological effects of intradiscal recombinant human bone morphogenetic protein-2 on the injured intervertebral disc: an animal experiment.

Study Design. Prospective analysis. Objective. To investigate biologic influences of recombinant human bone morphogenetic protein (rhBMP)-2 on intervertebral discs after anular tears. Summary of Background Data. Treatments for intervertebral disc injury or degeneration are unsatisfactory. rhBMP-2, a high-potency osteoinductive and chondroinductive substance, is approved for use in anterior lumbar interbody fusions. rhBMP-2 stimulates the proliferation of rat disc cells and the secretion of extracellular matrix in vitro. In vivo responses in the intervertebral disc after anular tears are rarely studied. Methods. Twenty New Zealand white rabbits received full-thickness anular tears and intradiscal injections of saline (control) and rhBMP-2 0.1 mg with and without coral grafts at L2–L3, L3–L4, and L4–L5, respectively. Three died or had infection. Therefore, 17 underwent radiography and sacrifice at 12 weeks. Spinal sections were stained with hematoxylin and eosin to examine responses to rhBMP-2. Results. Radiographs revealed degenerative changes, such as disc space narrowing and irregularity, subchondral sclerosis, osteophyte formation, and hypertrophy of vertebral endplates in all groups. Degeneration was more frequent and severe with rhBMP-2 with (P < 0.01) and without (P < 0.05) coral than with saline. Two rabbits receiving rhBMP-2 and coral achieved solid interbody bony fusion. New bone formation was noted in 2 controls, in 3 animals treated with rhBMP-2, and in 4 treated with rhBMP-2 and coral. Vascularity and fibroblast proliferation increased with rhBMP-2 (n = 14) and rhBMP-2 with coral (n = 9) compared with control (n = 3; P < 0.01 and P = 0.03, respectively). Inflammatory infiltrates increased with rhBMP-2 (n = 8) compared with control (n = 2; P = 0.03). Conclusions. Degenerative changes were more frequent and severe in the groups treated with rhBMP-2 with or without coral in radiographic findings. In histopathologic findings, rhBMP-2 promoted hypervascularity and fibroblast proliferation of the intervertebral disc after an anular tear.

IL-20 May Contribute to the Pathogenesis of Human Intervertebral Disc Herniation

Study Design. The gene expression of interleukin (IL)-20 on human herniated intervertebral disc. Objective. To elucidate the role of novel cytokine IL-20 in the pathogenesis of human intervertebral disc (IVD) herniation. Summary of Background Data. IL-20 is involved in inflammatory diseases such as psoriasis, atherosclerosis, and rheumatoid arthritis, etc. However, IL-20 is never reported to be associated with the pathogenesis of human disc herniation. Methods. Twenty consecutive patients who were diagnosed with IVD herniation and received open discectomy were included in this study. The retrieved disc material specimens and the isolated primarily cultured disc cells were immunohistochemically stained to detect the expression of IL-20 and its receptor subunits (IL-20R1, IL-20R2, and IL-22R1). Besides, to investigate the in vitro response of IL-20 on human herniated intervertebral disc, we analyzed the effects of IL-20 alone, in combination with IL-1&bgr;, and IL-1&bgr; alone on the gene expression and protein levels of various cytokines, chemokines, matrix metalloproteinases (MMPs), etc. Results. IL-20 and its receptors were detectable in human herniated disc tissues and isolated disc cells. In vitro, IL-1&bgr; induced the expression of IL-20. Furthermore, IL-20 induced transcripts of IL-1&bgr;, IL-6, vascular endothelial growth factor (VEGF), MMP-3, and monocyte chemoattractant protein (MCP-1) on primarily cultured human disc cells. IL-1&bgr; induced transcripts of IL-1&bgr;, IL-6, IL-8, VEGF, MMP3, and MCP-1. IL-20 combined with IL-1&bgr; induced transcripts of tumor necrosis factor-&agr; (TNF-&agr;), IL-1&bgr;, IL-6, IL-8, MMP-3, and MCP-1 to a level higher than those found in cells treated with IL-20 or IL-1&bgr; alone.Enzyme-linked immunosorbent assay, analysis also showed that IL-20 combined with IL-1&bgr; up-regulated the secretion of TNF-&agr;, IL-6, IL-8, and MCP-1. Conclusion. IL-20 induces proinflammatory, chemotaxtic, and matrix degradative responses in IVD cells especially in combination with IL-1&bgr;. Our study suggests that IL-20 plays an important role in the pathogenesis of disc herniation.

Rare clinical experiences for surgical treatment of melanoma with osseous metastases in Taiwan

BackgroundMalignant melanoma occurs infrequently in Taiwan. Once it has progressed into osseous metastases, the prognosis is poor. There are no reported clinical experiences of surgical management in this area.MethodsTo improve our understanding of the rare clinical experiences, we retrospectively investigated clinical characteristics, radiological findings, treatment modalities, survival outcomes and prognoses of 11 Taiwanese patients with osseous metastasis of melanoma treated surgically at two national medical centers, National Taiwan University Hospital and National Cheng Kung University Hospital from January 1983 to December 2006.ResultsSix patients suffered from acral-lentiginous melanoma. Nine patients sustained multiple osseous metastases and most lesions were osteolytic. Nine patients also had sustained metastases to other organs including liver, lungs, lymph nodes, brain and spleen. Second malignancies including lung cancer, thyroid papillary carcinoma, renal cell carcinoma and cervical cancer co-existed in four patients. The interval from the initial diagnosis of melanoma to the clinical detection of osseous metastases varied from 0–37.8 months (mean 9.75 months). Metastatic melanoma was invariably fatal; the mean survival time from bone metastases to death was 5.67 months.ConclusionDue to the high morbidity and poor survival of Taiwanese patients with osseous metastases of melanoma, surgical treatment should be directed towards pain relief and the prevention of skeletal debilitation in order to maintain their quality of life.

An investigation of a cluster of cervical herniated discs among container truck drivers with occupational exposure to whole-body vibration

An investigation of a cluster of cervical herniated discs among container truck drivers with occupational exposure to whole‐body vibration: Fan‐Yun Lan, et al. Department of Occupational and Environmental Medicine, National Cheng Kung University Hospital, Taiwan

Adjacent disc and facet joint degeneration in young adults with low-grade spondylolytic spondylolisthesis: A magnetic resonance imaging study

BACKGROUND/PURPOSEnPremature adjacent-level degeneration has been attributed to vertebral fusion, but spondylolisthesis has not been reported as a pathological factor responsible for the degeneration of adjacent disc and facet joint. We hypothesized that the degeneration of disc and facet joints in the adjacent levels is correlated with spondylolisthesis.nnnMETHODSnMagnetic resonance images of 35 symptomatic young adults (16-29 years old) with low-grade L5-S1 spondylolytic spondylolisthesis (Meyerding Grade 1 or 2) and 50 symptomatic young referents (20-29 years old) with L5-S1 disc herniation without spondylolisthesis were recruited to compare the differences between disc and facet-joint degenerations at the olisthetic and adjacent levels using the Mantel extension test.nnnRESULTSnThere were statistically significant degenerative changes of the discs and facet joints at the olisthetic and adjacent levels of patients with spondylolytic spondylolisthesis compared with the reference group. There is a trend that the disc and facet joints degenerate the most at the olisthetic level and become less affected at adjacent levels away from the lesion of pars defect.nnnCONCLUSIONnLow-grade spondylolytic spondylolisthesis was associated with significant degenerations of the disc and facet joints at olisthetic and adjacent levels in young adults.

Rare occurrence of inflammatory bowel disease in a cohort of Han Chinese ankylosing spondylitis patients- a single institute study

Despite a high prevalence of ankylosing spondylitis (AS) in Han Chinese, the clinical experience remains very limited in the extra-articular presentation of inflammatory bowel disease (IBD). A monocentric retrospective study was performed for the AS-associated IBD manifestation. This study analyzed AS patients fulfilling the 1984 revised New York diagnostic criteria, excluding those who had the onset of IBD before or concurrently with the diagnosis of AS, for their demographic, clinical, laboratory, radiological, pathological and medication data, particularly in the usage of anti-TNF monoclonal antibody. Among 988 AS patients with 19.8% female, 4 (0.4%) had the overt IBD presentation, one female and 3 male aged 28 to 47 years (38.8u2009±u20094.6), all ulcerative colitis with the characteristic histopathological findings. At the onset of colitis, all had a long-term disease duration of 10 to 25 years (17.5u2009±u20096.5) and high BASDAI 7.5 to 8.8 (8.2u2009±u20090.5) with the hip joint involvement. There were recurrent flares of colitis despite the treatment with corticosteroids and messalazopyrin/salazopyrin, and no relapses of IBD were observed for 6.0u2009±u20091.1 years after the adalimumab (ADA) therapy. In this retrospective cohort, we demonstrate the rarity of AS-associated IBD manifestation in Han Chinese with a beneficent effect from the ADA therapy.

MULTICENTRIC RETROPERITONEAL LEIOMYOSARCOMA WITH SATELLITE LESIONS NOT FOUND ON PET-CT: A CASE REPORT AND LITERATURE REVIEW

Most retroperitoneal leiomyosarcomas are clinically silent and are usually detected late, so a large size main tumor accompanied by satellite lesions might be presented. We report a case of a large multicentric retroperitoneal leiomyosarcoma with satellite lesions in the left iliac region, mimicking an abscess, was found on pre-operative pelvic computed tomography (CT). Positron emission tomography (PET-CT) was performed, but revealed only focal bony destruction of the left ilium and no discernable lesions in the abdomen. After resection of the iliacus satellite lesion, CT and magnetic resonance imaging (MRI) of the abdomen revealed another huge retroperitoneal leiomyosarcoma with invasion of the left kidney and ureter, descending colon and left iliac arteries. The patient was then treated with a multidisciplinary extensive excision operation. The clinical presentation, operative findings and imaging findings were reported and related articles were reviewed.