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 eight-month history 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 thoracic and 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.

The focal calcification or ossification of 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 year.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 40-year-old Indian female patient who sought medical attention with a six month history of paraesthesia of the lower limbs and progressive difficulty in walking.The clinical profile, together with computed tomography and magnetic resonance imaging of the spine, led to a diagnosis of compressive lumbar myelopathy due to ossification of the ligamentum flavum of lumbar spine.The patient underwent laminectomy and dissection of some of the affected ligamentum flavum.After three months of clinical follow-up, the patient had progressed favorably, having no sensory complaints and again becoming ambulatory. CASE REPORT:A previously healthy 40-year-old female patient sought medical attention at our hospital.The patient presented with a 2-month history of ascending paraesthesia of the left leg, with progressive worsening and right leg involvement, accompanied by reduced (right and left) leg muscle strength.She reported lower back discomfort.She also found difficulty in sitting and walking showing signs of neurological claudication.Neurological examination revealed paraparesis.A computed tomography (CT) scan of the lumbar spine revealed the following: calcification of ligament flavum at L2-L3 to L4-L5 levels worst at L3-L4 and lateral recess stenosis at L3-L4 and L4-L5.

The ossification of the ligamentum flavum (OLF) is a rare cause of thoracic myelopathy (TM) and most often occurs among East Asian countries such as Japan, Korea, and China. It is rare in other ethnic groups and in individuals below the age of 50 years. 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 48-year-old male patient who came to medical attention with a 2-month history of paresthesia 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 TM due to OLF in the thoracic spine. The patient underwent endoscopic over-the-top dorsal decompression and resection of the affected ligamentum flavum, without any intraoperative complications. After surgery, the patient had progressed favorably, having no sensory complaints and again becoming ambulatory.

Introduction: Focal ossification of the ligamentum flavum (OLF) is a rare cause of thoracic myelopathy. The lower thoracic spine is most frequently affected and the patients present initially with posterior column disturbances followed by progressively increasing spastic paraparesis. The pathogenesis of OLF has not been conclusively established. Materials and Methods: Five patients with thoracic myelopathy due to OLF underwent decompressive laminectomy and excision of the ligamentum flavum. Magnetic resonance (MR) images consistently revealed a linear or beak-like excrescence, uniformly hypodense on T1- and T2-weighted images, situated posterior to the thecal sac. A comparison of the preoperative neurological status and at follow-up was done using the Japanese Orthopaedic Association and Nurick scores modified for thoracic myelopathy. Results: Decompressive laminectomy with excision of the OLF resulted in significant improvement in motor weakness and gait in 4 (1 excellent, 2 good, and 1 fair) patients who had slow-onset, but progressive compression, OLF. The patient who had acute traumatic spinal injury did not recover despite decompression and rehabilitation. All improved in their gait and spasticity, but 4 patients had persistent sensory deficit. Conclusion: OLF can significantly contribute to a spatial reduction of the thoracic spinal canal, resulting in slowly progressive paraparesis or acute paraplegia after trauma to the back. The T2-weighted sagittal image of MR imaging is the modality of choice for screening the longitudinal extent of OLF, with increased diagnostic accuracy when combined with computed tomographic myelogram. Neurological improvement usually occurs following decompression laminectomy with or without excision of the OLF. However, the persistence of residual numbness or weakness at follow-up may be due to irreversible changes within the cord as a result of severe thecal compression and the delay between the onset of initial symptoms/signs and surgical decompression. Prognosis remains poor for acute myelopathy with pre-existing OLF, despite surgery.

Management of thoracic myelopathy caused by ossification of the posterior longitudinal ligament combined with ossification of the ligamentum flavum—a retrospective study

Ossification of the ligamentum flavum (OLF) is a possible cause of thoracic myelopathy. We report two rare cases with recurrent thoracic myelopathy caused by OLF markedly re-extended at the same intervertebral level after the primary surgery. Both patients had thoracic myelopathy caused by OLF and underwent decompressive laminectomy and resection of the OLF in the primary surgery. However, the neurological conditions gradually deteriorated following recovery after the primary surgery due to the recurrent OLF at the same intervertebral level. These patients were successfully treated by revision surgery via resection of the recurrent OLF and posterior spinal fusion with instrumentation. Two years after the second surgery, the neurological disturbance was resolved satisfactorily, and re-growth of the resected ossified lesion was not observed. The recurrence of OLF following resection of the ossified lesions is exceedingly rare but should be noted in patients treated surgically for thoracic myelopathy due to OLF.

Characteristics of ossification of the spinal ligament; incidence of ossification of the ligamentum flavum in patients with cervical ossification of the posterior longitudinal ligament - Analysis of the whole spine using multidetector CT.

Retrospective review. To describe a safe surgical procedure, en bloc resection of the posterior wall of the thoracic canal, for the decompression of severe thoracic myelopathy caused by tuberous ossification of the ligamentum flavum (OLF). OLF has been widely recognized as a cause of thoracic myelopathy in East Asia. Surgical decompression of thoracic myelopathy caused by OLF is technically demanding. Although several surgical decompression procedures have been described, acute neurological deterioration is common. Eighteen patients with severe thoracic myelopathy caused by tuberous OLF underwent posterior decompression via segmental en bloc resection of the posterior wall of the thoracic canal. The ossified ligamentum flavum, laminae, and partial facet joints of each segment were resected en bloc. Ossified dura mater was removed if present. Posterior fixation with pedicle screws was followed by lateral bone graft fusion. The mean preoperative modified Japanese Orthopaedic Association score (total score, 11) was 4.1 (range, 2-5). Postoperatively, no neurological deterioration occurred, and all patients improved clinically. With an average follow-up of 31.2 months (range, 24-42 mo), the average modified Japanese Orthopaedic Association score was 7.8 (range, 6-10), representing a 2- to 5-point improvement. The average improvement rate was 55.2% (range, 33.3%-83.3%). Most patients were functionally independent at the last follow-up. Forty ossified segments were resected. The average time required for the resection of 1 segment was 77 minutes. Intraoperatively, dural ossification was noted in 11 patients. Complete resection was performed in all patients. Cerebrospinal fluid leakage occurred in 5 patients. Segmental en bloc resection of the posterior wall of the thoracic canal is a safe and effective alternative for OLF-related severe thoracic myelopathy.

Focal ossification of the ligamentum flavum (OLF) forms one of the rare causes of thoracic myelopathy. The lower thoracic spine is most frequently affected and the patients present with initial posterior column disturbances followed by progressively increasing spastic paraparesis. The pathogenesis of OLF has not been conclusively established. Five patients with thoracic myelopathy due to OLF underwent decompressive laminectomy and excision of the ligamentum flavum. Their MRI delineated a linear or beak like excrescence, uniformly hypo-intense on T1 and T2 weighted images, situated posterior to the thecal sac. A comparison between the preoperative neurological status and the status at follow-up was done using Harsh's myelopathic grading. Decompressive laminectomy followed by the drilling of the OLF and its excision, occasionally along with the adherent outer layer of the dura, resulted in significant improvement in motor weakness and tingling sensations. However, at the last available follow-up, none of the patients had retained their ability to run briskly (grade I) and all of them had residual spasticity. OLF may significantly contribute to a spatial reduction of the thoracic spinal canal resulting in paraparesis. The T2 weighted sagittal image of the magnetic resonance imaging (MRI) is the modality of choice for screening of the longitudinal extent of the OLF. A rapid neurological improvement occurs following decompressive laminectomy and excision of the OLF. However, the persistence of residual spasticity at follow-up may be due to irreversible changes within the cord by the significant thecal compression and the delay between the onset of initial symptoms and signs and surgical decompression.

The ossification of the ligamentum flavum (OLF) is one of the major causes of thoracic myelopathy. Previous studies indicated there might be a potential link between metabolic disorder and pathogenesis of OLF. The aim of this study was to determine the potential role of metabolic disorder in the pathogenesis of OLF using the strict bioinformatic workflow for metabolism-related genes and experimental validation. A series of bioinformatic approaches based on metabolism-related genes were conducted to compare the metabolism score between OLF tissues and normal ligamentum flavum (LF) tissues using the single sample gene set enrichment analysis. The OLF-related and metabolism-related differentially expressed genes (OMDEGs) were screened out, and the biological functions of OMDEGs were explored, including the Gene Ontology enrichment analysis, Kyoto Encyclopedia of Genes and Genomes enrichment analysis, and protein-protein interaction. The competing endogenous RNA (ceRNA) network based on pairs of miRNA-hub OMDEGs was constructed. The correlation analysis was conducted to explore the potential relationship between metabolic disorder and immunity abnormality in OLF. In the end, the cell experiments were performed to validate the roles of GBE1 and TNF-α in the osteogenic differentiation of LF cells. There was a significant difference of metabolism score between OLF tissues and normal LF tissues. Forty-nine OMDEGs were screened out and their biological functions were determined. The ceRNA network containing three hub OMDEGs and five differentially expressed miRNAs (DEmiRNAs) was built. The correlation analysis between hub OMDEGs and OLF-related infiltrating immune cells indicated that metabolic disorder might contribute to the OLF via altering the local immune status of LF tissues. The cell experiments determined the important roles of GBE1 expression and TNF-α in the osteogenic differentiation of LF cells. This research, for the first time, preliminarily illustrated the vital role of metabolic disorder in the pathogenesis of OLF using strict bioinformatic algorithms and experimental validation for metabolism-related genes, which could provide new insights for investigating disease mechanism and screening effective therapeutic targets of OLF in the future.

Ossification of the ligamentum flavum (OLF) is a primary cause of thoracic myelopathy. A relatively safe surgical technique based on radiological type is described for OLF-induced thoracic myelopathy. Forty patients with thoracic myelopathy caused by OLF were studied retrospectively. The OLF was divided into fused and non-fused types according to the computed tomography and magnetic resonance imaging findings. All patients underwent posterior decompression. For the fused type, open-door laminectomy and for the non-fused type, French-door laminectomy surgical techniques were adopted. Preoperative, postoperative, and follow-up neurological conditions were evaluated using the modified Japanese Orthopaedic Association (mJOA) score. The mean duration of symptoms was 9.2±11.5 and 8.4±9.7 months in the non-fused and fused groups, respectively. The apex of OLF at the most severely compressed level was located at 2.7±1.9 mm above the disc level: 2.4±1.6 and 3.0±2.2 mm in the non-fused and fused groups, respectively. The preoperative mJOA scores were 5.0±1.1 and 4.2±0.9 in the non-fused and fused groups, respectively. After the operation, the neurological deficits were improved in all patients. With an average follow-up of 33.9 months, the mJOA score was ultimately improved in both groups. In OLF-induced thoracic myelopathy, the en-bloc elevation of the laminae with the OLF plaque is emphasized at the key site for surgical decompression. Based on the present classification of OLF, different surgical strategies should be adopted for a safe neurological decompression.

Background:Ossification of the ligamentum flavum (OLF) is being increasingly recognized as a cause of thoracic myelopathy. This study was to describe a rare clinical entity of spinal cord kinking (SK) in thoracic myelopathy secondary to OLF.Methods:The data of 95 patients with thoracic myelopathy secondary to OLF were analyzed retrospectively. The incidence and location of SK were determined using preoperative magnetic resonance imaging (MRI). The clinical presentation and radiological characteristics in patients with SK were analyzed. Posterior en bloc laminectomy with OLF was performed, and the surgical results were evaluated.Results:SK was found in seven patients (7.4%) based on preoperative MRI. The patients included one male and six females with an average age of 55.6 years (range, 48–64 years). Five patients presented with radiculomyelopathy and two presented with typical thoracic myelopathy of spastic paraparesis. In all cases, the kinking was located just above the end of the spinal cord where the conus medullaris (CM) was compressed by the OLF. The degree of SK varied from mild to severe. The tip of the CM was located between the upper third of T11 to the lower third of L1, above the lower edge of L1. With an average follow-up of 30.4 months, the modified Japanese Orthopedic Association score significantly improved from 5.7 ± 1.8 preoperatively to 8.9 ± 1.4 postoperatively (t = 12.05; P < 0.0001) with an improvement rate of 63.1 ± 12.3%.Conclusions:SK is a rare radiological phenomenon. It is typically located at the thoracolumbar junction, where the CM is compressed by the OLF. Our findings indicate that these patients may benefit from a posterior decompressive procedure.

Ossification of the ligamentum flavum (OLF) is a rare cause of thoracic myelopathy. The aim of this study was to identify factors associated with the surgical outcome on the basis of preoperative clinical and radiological findings. Data obtained in 26 patients whot underwent posterior decompression for thoracic myelopathy, caused by thoracic OLF, were analyzed retrospectively. Patient age, duration of symptoms, OLF type, preoperative and postoperative neurological status using the Japanese Orthopedic Association (JOA) scoring system, surgical outcome, and other factors were reviewed. We compared the various factors and postoperative prognosis. All patients had undergone decompressive laminectomy and excision of the OLF. Using the JOA score, the functional improvement was excellent in 8 patients, good in 14, fair in 2, and unchanged in 2. A mean preoperative JOA score of 6.65 improved to 8.17 after an average of 27.3 months. According to our analysis, age, gender, duration of symptoms, the involved spinal level, coexisting spinal disorders, associated trauma, intramedullary signal change, and dural adhesions were not related to the surgical outcome. However, the preoperative JOA score and type of OLF were the most important predictors of the surgical outcome. Early diagnosis and sufficient surgical decompression could improve the functional prognosis for thoracic OLF. The postoperative results were found to be significantly associated with the preoperative severity of myelopathy and type of OLF.

Thoracic myelopathy occurs less frequently than lumbar myelopathy. There are several causes of thoracic myelopathy of which ossification of the ligamentum flavum (OLF) is one. OLF has several unique features, arising posteriorly and causing proprioceptive issues first before extending to cause motor and sensory loss. We present a case of a 58-year-old gentleman with a six-month history of progressive lower limb weakness, numbness, back pain and recurrent falls due to OLF. Magnetic resonance and computed tomography imaging revealed extensive thoracic OLF and concomitant facet hypertrophy involving T6-7, T7-8, T9-10, T10-11 and L1-2. Severe central canal stenosis and L1-2 cauda equina root compression were also seen on radiological imaging. The patient developed sphincter disturbance during his admission and had difficulty passing urine. He underwent physiotherapy but was only able to sit and stand with the help of a walking frame at best. He did not regain motor or sensory function in his lower limbs although his back pain improved. Surgical decompression is associated with good neurological outcomes in OLF. Despite this, our patient declined surgery and opted for conservative therapy instead. We wish to highlight a rare case of thoracic myelopathy and the potentially irreversible neurological deterioration that occurs if there is no early surgical intervention.

Study Design:Retrospective cross-sectional study.Objectives:There is insufficient data on the clinical features of ossification of the ligamentum flavum (OLF) of the thoracic spine and the risk of progression of ossified lesions. The link between obesity and ossification of the posterior longitudinal ligament (OPLL), which frequently coexists with OLF, has been demonstrated. However, the link between obesity and OLF has not been recognized. We aimed to determine the prevalence of obesity in thoracic OLF and whether the severity of OLF is associated with the degree of obesity.Methods:A total of 204 symptomatic Japanese subjects with thoracic OLF and 136 subjects without spinal ligament ossification as controls were included. OLF subjects were divided into 3 groups: 1) localized OLF (OLF <2-intervertebral regions); 2) multilevel OLF (OLF ≥3-intervertebral regions); and 3) OLF + OPLL. The severity of OLF was quantified using the OLF index using computed tomography imaging of the entire spine.Results:The proportion of severely obese subjects (BMI ≥ 30 kg/m2) was significantly higher both in the multilevel OLF group (25.5%) and the OLF + OPLL group (44.3%) than in the localized OLF group (3.6%) and the control group (1.4%) (P < 0.01). BMI, age, and coexistence of cervical OPLL and lumbar OLF were associated with thoracic OLF index in the multiple regression analysis.Conclusions:Our findings demonstrated that obesity is a distinct feature of multilevel OLF in the thoracic spine and that the severity of OLF is associated with the degree of obesity.