Ossification of the yellow ligament causing thoracic cord compression

SRμCT Reveals 3D Microstructural Alterations of the Vascular and Neuronal Network in a Rat Model of Chronic Compressive Thoracic Spinal Cord Injury

The complex pathology of chronic thoracic spinal cord compression involves vascular and neuroarchitectural repair processes that are still largely unknown. In this study, we used synchrotron radiation microtomography (SRμCT) to quantitatively characterize the 3D temporal-spatial changes in the vascular and neuronal network after chronic thoracic spinal cord compression in order to obtain further insights into the pathogenesis of this disease and to elucidate its underlying mechanisms. Direct 3D characterization of the spinal cord microvasculature and neural microstructure of the thoracic spinal cord was successfully reconstructed. The significant reduction in vasculature and degeneration of neurons in the thoracic spinal cord visualized via SRμCT after chronic compression were consistent with the changes detected by immunofluorescence staining. The 3D morphological measurements revealed significant reductions of neurovascular parameters in the thoracic spinal cord after 1 month of compression and became even worse after 6 months without relief of compression. In addition, the distinct 3D morphological twist and the decrease in branches of the central sulcal artery after chronic compression vividly displayed that these could be the potential triggers leading to blood flow reduction and neural deficits of the thoracic spinal cord. Our findings propose a novel methodology for the 3D analysis of neurovascular repair in chronic spinal cord compression, both qualitatively and quantitatively. The results indicated that compression simultaneously caused vascular dysfunction and neuronal network impairment, which should be acknowledged as concurrent events after chronic thoracic spinal cord injury. Combining neuroprotection with vasoprotection may provide promising therapeutic targets for chronic thoracic spinal cord compression.

Ossification of the yellow ligament in the cervical spine - an unusual location

Ossification of the yellow ligament (OYL) or ligamentum flavum, usually occurs in the thoracic spine. Focal OYL occurring in the cervical spine is considered rare and is sparsely reported in the literature. We came across a 30-year-old male patient with progressive left upper limb and bilateral lower limb weakness over a period of 3 months, associated with an unsteady gait. Clinical examination revealed bilateral generalized hyper-reflexia in both upper and lower limbs, inverted supinator jerk, Hoffman’s sign and clonus. Myelopathy due to cord compression was suspected and further investigations were done. MRI and CT scans revealed a bony mass in relation to the C6 spinous process projecting anterosuperiorly and narrowing the cervical spinal canal causing cord signal changes from C4 to C6 levels. In view of the deteriorating neurological status, immediate surgery in the form of decompression and posterior stabilization from C4-C6 was performed. Patient gradually recovered after surgery and attained full functional status. We report this case considering the unusual location of OYL and its successful management.

Lamina osteotomy and replantation with miniplate fixation for thoracic myelopathy due to ossification of the ligamentum flavum

Lamina osteotomy and replantation with miniplate fixation is often used to treat benign intradural tumors, effectively preventing nerve entrapment and postoperative spinal deformities. However, no studies report using this technique to treat thoracic myelopathy due to ossification of the ligamentum flavum (OLF). This article reports the clinical outcome of a series of 18 cases of contiguous multilevel OLF treated by lamina osteotomy and replantation with miniplate fixation.Eighteen consecutive patients at the authors' institution were treated between 2008 and 2010 for contiguous multilevel OLF. Clinical efficacy, operative time, blood loss, sagittal alignment, and complications were investigated. Japanese Orthopaedic Association scale scores improved from 4.7±1.4 preoperatively to 7.9±1.3 three months postoperatively and 8.8±1.3 at final follow-up (P<.01), with a mean recovery rate of 67.8%±13.1%. No significant kyphotic deformity occurred postoperatively, and local kyphosis in the treated area increased by a mean of only 1.9°±1.0° at final follow-up. No patient required additional surgery due to spinal canal reobstruction and progressive spinal deformity. Cerebrospinal fluid leakage occurred in 4 patients and resolved after repair. Pulmonary infection and deep venous thrombosis occurred in 1 patient who was discharged with no complications after routine treatment.Lamina osteotomy and replantation with miniplate fixation is an effective therapeutic option for thoracic myelopathy due to contiguous multilevel OLF compression. The technique provides adequate decompression and stabilized sagittal alignment and avoids invasion of the spinal canal by scar tissue.

ANALYSIS OF DURAL-SAC OCCLUSION IN A LUMBAR SPINAL MOTION SEGMENT FE MODEL

Occlusion of dural-sac in the lumbar spine was quantitatively analyzed by utilizing one motion segment of finite element lumbar spine model developed in this study. And the mechanism of occlusion, considering both static and viscous behavior of materials, was also investigated with various loading conditions. Occlusion was quantified by calculating the cross sectional area change or volumetric changes of dural-sac. In the static analysis, it was found that less than 2 kN of compressive load could not produce dural-sac occlusion but the compression together with extension moment was more likely to produce the dural-sac occlusion. The 7.4% of occlusion was obtained when the 8 Nm of extension moment was added to 2 kN of compressive load which alone did not create any occlusion. The magnitude of occlusions was increased to 10.5% as the extension moment become to 10 Nm with the same 2 kN of compressive load. In creep analysis, 10 Nm extension, kept for 3600 seconds, induced 6.9% of occlusion and 2.4% of volume reduction in dural-sac. However, flexion moment did not produce any occlusion in dural-sac but increased the volume instead because it caused stretching of dural-sac coupled with vertebra motion. As a conclusion, occlusions resulted mainly from the slackening of ligamentum flavum and disc bulging, and the amount of occlusion was strongly dependent with loading condition and visco-elastic behavior of materials as well.

Symptomatic disc herniation and serum lipid levels

Insufficient blood supply to the intervertebral disc (IVD) has been proposed to play a role as causative factor in IVD degeneration. There is an association between IVD diseases and increased risk of dying of ischaemic heart disease. Obesity and tobacco are potential risk factors for degenerative IVD disease. High blood cholesterol and triglycerides serum levels are risk factors for atherosclerosis, and could be responsible for a decreased in the blood supply to the already poor vascularized IVD. We performed a frequency-matched case-control study to determine the serum levels of patients with symptomatic herniated lumbar disc. We examined the fasting serum lipid levels in 384 subjects who were operated at our institution. Group 1 included 169 consecutive patients (115 men and 54 women; mean age: 59.1 years, range 29-85) who underwent surgery for symptomatic disc herniation. Group 2 (control group) included 169 patients (115 men and 54 women; mean age: 61 years, range 26-86) who underwent arthroscopic meniscectomy for a meniscal tear in the same period. These patients were frequency-matched by age (within 3 years) and gender with patients of Group 1. Sera were extracted from blood samples and the concentrations of total cholesterol (TC) and triglycerides (TG) were determined. When comparing the two groups, patients with symptomatic herniated lumbar disc showed statistically significant higher triglyceride concentration (P = 0.02) and total cholesterol concentration (P = 0.01). Serum lipid levels may be a risk factor for IVD pathology. An enhanced understanding of these factors holds the promise of new approaches to the prevention and management of IVD pathology.

Ossification of the ligamentum flavum in a Caucasian man

Abnormal ossification of spinal ligaments is a well-known cause of myelopathy in East Asian populations, with ossification of the ligamentum flavum (OLF) and the posterior longitudinal ligament being the most prevalent. In Caucasian populations, OLF is rare, and there has been only 1 documented case of the disease affecting more than 5 spinal levels. In this report, the authors describe the clinical presentation, imaging characteristics, and management of the second published case of a Caucasian man with OLF affecting almost the entire thoracic spine. The literature is then reviewed with regard to OLF epidemiology, pathogenesis, presentation, and treatment.

Spinal compression due to ossified yellow ligament: a short series of 5 patients and literature review

BACKGROUND

Ossification of ligamentum flavum in the thoracic region causing compressive myelopathy among middle-aged patients is a poorly described entity.

CASE DESCRIPTION

Five patients of Indian origin with OYL are described. Their clinical presentations, surgical options, and long-term outcome are presented. Radiologic and clinical follow-up of one of the patient is described over a span of 10 years.

CONCLUSIONS

Decompressive laminectomy and excision of the OYL is the commonly performed surgical procedure. A rapid neurologic improvement follows decompression. The persistent spasticity in certain patients is attributed to irreversible changes within the cord. The disease is thought to be progressive in nature. The prolonged follow-up of these patients suggests that the long-term prognosis is poor. Selective racial involvement and variable clinical presentations, with treatment options, are discussed.

Thoracic spinal cord compression by ligamentum flavum ossifications

Ossification of the ligamentum flavum is common in Japan but rare in Western countries. Myelopathy of variable severity is a possible complication. Extension of the lesions over several levels at the thoracic spine is exceedingly rare. We report a new case in a 50-year-old man who had slowly progressive spinal cord compression with a sensory level at the navel. Computed tomography (CT) and magnetic resonance imaging (MRI) of the thoracic spine showed calcium-density masses that were in contact with the neural arches and bulged into the spinal canal at T5/T6, T7/T8, T9/T10, and T10/T11. Laboratory test findings were unremarkable. Surgical decompression by laminectomy and foraminotomy was followed by a favorable outcome. Histology showed extensive areas of bone metaplasia associated with calcific deposits. The diagnosis, treatment, and possible etiologies of this rare condition are discussed based on a literature review.