Thoracic myelopathy due to ossified hypertrophied ligamentum flavum

Calcification of ligamentum flavum is a rare disease that was found to occur almost exclusively in Japanese population. However the disease is now being increasingly recognized as a cause of thoracic myeloradiculopathy in Indian Population. We report a case of thoracic myelopathy at multiple levels due to ossified and hypertrophied ligamentum flavum

Calcification of the ligamentum flavum in the thoracolumbar spine: an unusual cause of compressive myelopathy

The focal calcification or ossification of the ligamentum flavum is a rare cause of thoracic myelopathy and most often occurs among individuals of Japanese descent. It is rare in other ethnic groups and in individuals below the age of 50.It is most often described at the lower thoracic level, being uncommon in the lumbar region and rare in the cervical region. Here, we present the case of a 44-year-old White female patient who sought medical attention with an eightmonthhistory of paraesthesia of the lower limbs and progressive difficulty in walking. The clinical profile, together with computed tomography and nuclear magnetic resonance imaging of the spine, led to a diagnosis of compressive thoracic myelopathy due to ossification of the ligamentum flavum in the thoracicand lumbar spine. The patient underwent laminectomy and dissection of some of the affected ligamentum flavum, without any intraoperative complications. After three months of clinical follow-up, the patient had progressed favorably, having no sensory complaints and again becoming ambulatory.nul

Model of pathological collagen mineralization based on spine ligament calcification

The aim of the study was to determine the time of mineral growth in human spine ligaments using a mathematical model. The study was based on our previous research in which the physicochemical analysis and computed microtomography measurements of deposits in ligamenta flava were performed. Hydroxyapatite-like mineral (HAP) constituted the mineral phase in ligament samples, in two samples calcium pyrophosphate dehydrate (CPPD) was confirmed. The micro-damage of collagen fibrils in the soft tissue is the crystallization center. The growth of the mineral nucleus is a result of the calcium ions deposition on the nucleus surface. Considering the calcium ions, the main component of HAP, it is possible to describe the grain growth using a diffusion model. The model calculations showed that the growth time of CPPD grains was ca. a month to 6 years, and for HAP grains >4 years for the young and >5.5 years for the elderly patients. The growth time of minerals with a radius >400 μm was relatively short and impossible to identify by medical imaging techniques. The change of growth rate was the largest for HAP deposits. The mineral growth time can provide valuable information for understanding the calcification mechanism, may be helpful in future experiments, as well as useful in estimating the time of calcification appearanc

Ossification of yellow ligament-lesser known common cause of thoracic myelopathy in Indian subcontinent treated surgically

Background: To undertake a study which outlines the clinical and radiological features of ossification of yellow ligament (OYL) causing thoracic myelopathy (TM) in Indian subcontinent, to assess the outcomes of surgical resection of yellow ligament and compare different preoperative factors that contribute to be a risk factor in the overall post-surgical recovery rates (RR). Methods: A retrospective analysis of prospectively collected data from a cohort of 45 patients who visited our spine OPD from January 2012 to December 2019 who underwent surgical decompression for TM due to OYL was studied. The surgical outcomes and RR were calculated, compared and pre operative risk factors which could possibly be involved in giving poorer RR were analysed. Results: Our study included 45 patients who underwent surgical resection of OYL for TM. On comparison of post operative improvement in myelopathic symptoms, pre-operative mJOA score of 4.56 had increased significantly to 7.83 at 2 years follow up. While the majority (80%) of patients had an excellent and good recovery rate while 16% of patients had a fair recovery rate and 4% had no change at all in comparison to pre-operative mJOA scores. Preoperative risk factors for poor outcomes were also analysed. Conclusions: Early and timely before the onset or progression of any neurologic involvement. The pre operative risk factors which could give guarded prognosis and lower RR are, the presence of intramedullary signal changes (myelomalacia), >6-10 months of progressive pre operative symptoms and an mJOA<5

Degenerative Thoracic Myelopathy: A Scoping Review of Epidemiology, Genetics, and Pathogenesis.

STUDY DESIGN: Literature Review. OBJECTIVE: Myelopathy affecting the thoracic spinal cord can arise secondary to several aetiologies which have similar presentation and management. Consequently, there are many uncertainties in this area, including optimal terminology and definitions. Recent collaborative cervical spinal research has led to the proposal and subsequent community adoption of the name degenerative cervical myelopathy(DCM), which has facilitated the establishment of internationally-agreed research priorities for DCM. We put forward the case for the introduction of the term degenerative thoracic myelopathy(DTM) and degenerative spinal myelopathy(DSM) as an umbrella term for both DCM and DTM. METHODS: Following PRISMA guidelines, a systematic literature search was performed to identify degenerative thoracic myelopathy literature in Embase and MEDLINE. RESULTS: Conditions encompassed within DTM include thoracic spondylotic myelopathy, ossification of the posterior longitudinal ligament, ossification of the ligamentum flavum, calcification of ligaments, hypertrophy of ligaments, degenerative disc disease, thoracic osteoarthritis, intervertebral disc herniation, and posterior osteophytosis. The classic presentation includes girdle pain, gait disturbance, leg weakness, sensory disturbance, and bladder or bowel dysfunction, often with associated back pain. Surgical management is typically favoured with post-surgical outcomes dependent on many factors, including the causative pathology, and presence of additional stenosis. CONCLUSION: The clinical entities encompassed by the term DTM are interrelated, can manifest concurrently, and present similarly. Building on the consensus adoption of DCM in the cervical spine and the recent proposal of degenerative cervical radiculopathy(DCR), extending this common nomenclature framework to the terms degenerative spinal myelopathy and degenerative thoracic myelopathy will help improve recognition and communication

Loss of equilibrative nucleoside transporter 1 in mice leads to progressive ectopic mineralization of spinal tissues resembling diffuse idiopathic skeletal hyperostosis in humans

Diffuse idiopathic skeletal hyperostosis (DISH) is a noninflammatory spondyloarthropathy, characterized by ectopic calcification of spinal tissues. Symptoms include spine pain and stiffness, and in severe cases dysphagia and spinal cord compression. The etiology of DISH is unknown and there are no specific treatments. Recent studies have suggested a role for purine metabolism in the regulation of biomineralization. Equilibrative nucleoside transporter 1 (ENT1) transfers hydrophilic nucleosides, such as adenosine, across the plasma membrane. In mice lacking ENT1, we observed the development of calcified lesions resembling DISH. By 12 months of age, ENT1-/- mice exhibited signs of spine stiffness, hind limb dysfunction, and paralysis. Micro-computed tomography (μCT) revealed ectopic mineralization of paraspinal tissues in the cervical-thoracic region at 2 months of age, which extended to the lumbar and caudal regions with advancing age. Energy-dispersive X-ray microanalysis of lesions revealed a high content of calcium and phosphorus with a ratio similar to that of cortical bone. At 12 months of age, histological examination of ENT1-/- mice revealed large, irregular accumulations of eosinophilic material in paraspinal ligaments and entheses, intervertebral discs, and sternocostal articulations. There was no evidence of mineralization in appendicular joints or blood vessels, indicating specificity for the axial skeleton. Plasma adenosine levels were significantly greater in ENT1 -/- mice than in wild-type, consistent with loss of ENT1 - a primary adenosine uptake pathway. There was a significant reduction in the expression of Enpp1, Ank, and Alpl in intervertebral discs from ENT1-/- mice compared to wild-type mice. Elevated plasma levels of inorganic pyrophosphate in ENT1-/- mice indicated generalized disruption of pyrophosphate homeostasis. This is the first report of a role for ENT1 in regulating the calcification of soft tissues. Moreover, ENT1-/- mice may be a useful model for investigating pathogenesis and evaluating therapeutics for the prevention of mineralization in DISH and related disorders. © 2013 American Society for Bone and Mineral Research. Copyright © 2013 American Society for Bone and Mineral Research

Iatrogenic Spinal Cord Injury during Removal of the Inferior Articular Process in the Presence of Ossification of the Ligamentum Flavum

Ossified ligamentum flavum (OLF) is a condition of heterotopic lamellar bone formation within the yellow ligament. Some patients with OLF can be asymptomatic. However, asymptomatic OLF may not be obvious on preoperative MRI and could increase the risk of iatrogenic injury during treatments for unrelated spinal conditions. This report describes a case of spinal cord injury caused by the indirect transmission of force from an osteotome to an asymptomatic OLF during the resection of a thoracic inferior articular process (IAP). To prevent this outcome, we urge careful review of CT imaging in the preoperative setting and advocate the use of a high-speed drill instead of an osteotome during bone removal in the setting of an adjacent area of OLF

Ectopic Mineralization of Spinal Tissues in Mice Lacking Equilibrative Nucleoside Transporter 1

Equilibrative nucleoside transporter 1 (ENT1) regulates the bi-directional transfer of hydrophilic nucleosides, such as adenosine, across the plasma membrane. Mice lacking ENT1 developed calcified lesions resembling diffuse idiopathic skeletal hyperostosis (DISH) in humans. By 12 months of age, ENT1-/- mice exhibit spine stiffness, hind limb dysfunction, and paralysis. Histological examination of ENT1-/- mice revealed irregular accumulations of eosinophilic material in paraspinal ligaments and entheses, intervertebral discs, and sternocostal articulations. There was no evidence of mineralization in appendicular joints or blood vessels. Analysis of intervertebral disc tissues of 6 month old ENT1-/- and wild-type mice revealed reduced expression of mineralization inhibitors, including matrix gla protein (Mgp), ectonucleotide pyrophosphatase/phosphodiesterase 1 (Enpp1), progressive ankylosis (Ank), and osteopontin (Spp1). The expression of these genes was not altered in tissues which do not exhibit ectopic mineralization. Thus, a reduction of proteins that normally prevent soft tissue mineralization may induce the ectopic calcification of spinal tissues observed in ENT1-/- mice