Lumbar Ligamentum Flavum Research Articles

Prevalence, Radiological, and Pathological Findings of Ossification and Calcification of the Lumbar Spinal Ligamentum Flavum: A Comparative Study with Thoracic Lesions.

This study aimed to determine the prevalence of lumbar ligamentum flavum lesions and identify correlations between radiological and pathological findings. We conducted an observational cross-sectional study of 349 patients (lumbar: n = 296, thoracic: n = 39, lumbar and thoracic: n = 14, mean age: 69 ± 12 years, male: 74%) who underwent posterior surgery for thoracolumbar spinal canal stenosis between January 2008 and April 2023 at our hospital.Computed tomography (CT) revealed that the prevalence of ligamentum flavum lesions defined as a high-density area with a CT value of 200 Hounsfield Unit or higher in the lumbar and thoracic spine was 47% (147/310) and 85% (45/53), respectively. CT showed that most patients had radiologically suspected ossification in the lumbar (90%) and thoracic spine (98%) than radiologically suspected calcification. Lumbar lesions were thinner than the thoracic lesions (2.5 vs 3.7 mm, p < 0.01). Pathological examinations were performed in specimens collected from 34 cases (lumbar: n = 13, thoracic: n = 21), and ossification was found in 62% (8/13) and 95% (20/21) of lumbar and thoracic lesions (p = 0.02), respectively. Lastly, ossification was confirmed pathologically in 72% (8/11) and 95% (19/20) of lumbar and thoracic lesions that showed ossification on imaging (p = 0.13), respectively. The literature review revealed that the prevalence of the lumbar ligamentum flavum lesions varied from 1.5 to 35% and the patient population was mostly asymptomatic.Collectively, we found that the prevalence of lumbar ligamentum flavum lesions in symptomatic patients was greater than previously reported. Histologically confirmed ossification was less common in lumbar lesions than in thoracic lesions.

Measurement Analysis and Clinical Research of Lumbar Ligamentum Flavum and Lamina

Measurement Analysis and Clinical Research of Lumbar Ligamentum Flavum and Lamina

Endoscopic treatment of lumbar ligamentum flavum cyst by interlaminar approach: a minimally invasive and effective alternative to open surgery

Background and objectivesLumbar ligamentum flavum cyst is a rare spinal condition that can cause significant morbidity and neurological deficits. Traditional surgical treatment involves open surgery, which can be associated with prolonged recovery time and significant morbidity. In recent years, endoscopic treatment of lumbar ligamentum flavum cyst has emerged as a minimally invasive and effective alternative to open surgery, but only a few cases have been reported in the literature. This paper describes our experience with endoscopic resection of an L4/5 ligamentum flavum cyst through an interlaminar approach and reviews the literature on the treatment of lumbar ligamentum flavum cyst.MethodsAn 87-year-old man presented with lameness in the left leg, and magnetic resonance imaging (MRI) showed nerve compression by a ligamentum flavum cyst at the L4/5 intervertebral plane. The patient underwent endoscopic resection of the ligamentum flavum cyst through a left interlaminar approach with the facet joint preserved. The present study was approved by the Ethics Committee of our hospital. The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request. Text regarding patient consent is not applicable for this case.ResultsPostoperative clinical results improved significantly, and postoperative MRI showed complete cyst resection.ConclusionTotal endoscopic resection via an interlaminar approach provides a new minimally invasive approach for the surgical treatment of lumbar ligamentum flavum cyst, which can be used as a reference by clinicians.

Quantitative evaluation of the lumbar ligamentum flavum using MRI T2-mapping: Efficacy of its clinical application in patients with lumbar spinal stenosis

ObejectiveTo perform a magnetic resonance imaging T2-mapping of the ligamentum flavum in healthy individuals and patients with lumbar spinal stenosis scheduled for surgery and compare the T2 relaxation times. Subjects and MethodsThe T2 relaxation time of the ligamentum flavum was compared among 3 groups, healthy young individuals (H group (age< 50)), healthy middle-aged and older individuals (H group (age≥50)), and patients with lumbar spinal stenosis (L group). Additionally, the thickness of the ligament was measured in the axial image plane, and the occupied area ratio of each fiber was measured by staining the surgically obtained ligament, and each was correlated with the T2 relaxation time. We also evaluated the adhesion of the ligamentum flavum with the dura mater during the surgery. ResultsThe T2 relaxation times were significantly prolonged in H group (age ≥50) and L group (P < 0.001) compared to H group (age<50). The relationship between collagen fiber and T2 relaxation times was significantly positive (r = 0.720, P < 0.001). Moreover, the relaxation times were significantly prolonged in those with adhesion of the ligamentum flavum with the dura mater (P < 0.05). The cut-off for the relaxation time was 50 ms (sensitivity: 62.50%, false positive rate: 10.8%). ConclusionHealthy middle-aged and older individuals and patients with lumbar spinal stenosis and adhesion of the ligamentum flavum with the dura mater have prolonged T2 relaxation times. Hence, the adhesion between the ligamentum flavum and dura mater should be considered in cases with a relaxation time ≥50 ms.

Macrophage migration inhibitory factor takes part in the lumbar ligamentum flavum hypertrophy.

The present study aimed to observe the content difference of macrophage migration inhibitory factor [MIF; novoprotein recombinant human MIF (n-6his) (ch33)], TGFβ1 and MMP13 in patients with and without ligamentum flavum (LF) hypertrophy and investigate the roles of MIF in LF hypertrophy. The concentration of MIF, TGFβ1 and MMP13 in LF were detected by ELISA in a lumbar spinal stenosis (LSS) group and a lumbar disc herniation (LDH) group. Culture of primary LFs and identification were performed for the subsequent study. Cell treatments and cell proliferation assay by CCK-8 was performed. Western blot and quantitative PCR analysis were used to detect the expression of TGFβ1, MMP13, type I collagen (COL-1) and type III collagen (COL-3) and Src which were promoted by MIF. The concentration of MIF, TGFβ1 and MMP13 were higher in the LSS group compared with the LDH group. Culture of primary LFs and identification were performed. Significant difference in LFs proliferation occurred with treatment by MIF at a concentration of 40 nM for 48 h (P<0.05). The gene and protein expression of TGFβ1, MMP13, COL-1, COL-3 and Src were promoted by MIF (P<0.05). Proliferation of LFs was induced by MIF and MIF-induced proliferation of LFs was inhibited by PP1 (a Src inhibitor). MIF may promote the proliferation of LFs through the Src kinase signaling pathway and can promote extracellular matrix changes by its pro-inflammatory effect. MIF and its mediated inflammatory reaction are driving factors of LF hypertrophy.

Characterization of a Novel Model of Lumbar Ligamentum Flavum Hypertrophy in Bipedal Standing Mice.

ObjectiveTo explore the main causes of hypertrophied ligamentum flavum (HLF) and the possibility of using bipedal standing mouse model to simulate the pathological changes in human HLF.MethodsThirty‐two 8‐week‐old C57BL/6 male mice were randomly assigned to the experimental group (n = 16) and control group (n = 16). In the experimental group, mice were induced to adopt a bipedal standing posture by their hydrophobia. The experimental mice were maintained bipedal standing for 8 h a day with an interval of 2 h to consume food and water. The control mice were placed in a similar environment without bipedal standing. Eight 18‐month‐old C57BL/6 male mice were compared to evaluate the LF degeneration due to aging factor. Three‐dimensional (3D) reconstruction and finite element models were carried out to analyze the stress and strain distribution of the mouse LF in sprawling and bipedal standing postures. Hematoxylin and Eosin (HE), Verhoeff‐Van Gieson (VVG), and immunohistochemistry (IHC) staining were used to evaluate the LF degeneration of mice and humans. RT‐qPCR and immunofluorescence analysis were used to evaluate the expressions of fibrosis‐related factors and inflammatory cytokines of COL1A1, COL3A1, α‐SMA, MMP2, IL‐1β, and COX‐2.ResultsThe von Mises stress (8.85 × 10−2 MPa) and maximum principal strain (6.64 × 10−1) in LF were increased 4944 and 7703 times, respectively, in bipedal standing mice. HE staining showed that the mouse LF area was greater in the bipedal standing 10‐week‐old group ([10.01 ± 2.93] × 104 μm2) than that in the control group ([3.76 ± 1.87] × 104 μm2) and 18‐month‐old aged group ([6.09 ± 2.70] × 104 μm2). VVG staining showed that the HLF of mice (3.23 ± 0.58) and humans (2.23 ± 0.31) had a similar loss of elastic fibers and an increase in collagen fibers. The cell density was higher during the process of HLF in mice (39.63 ± 4.81) and humans (23.25 ± 2.05). IHC staining showed that the number of α‐SMA positive cells were significantly increased in HLF of mice (1.63 ± 0.74) and humans (3.50 ± 1.85). The expressions of inflammatory cytokines and fibrosis‐related factors of COL1A1, COL3A1, α‐SMA, MMP2, IL‐1β, and COX‐2 were consistently higher in bipedal standing group than the control group.ConclusionOur study suggests that 3D finite element models can help analyze the abnormal stress and strain distributions of LF in modeling mice. Mechanical stress is the main cause of hypertrophied ligamentum flavum compared to aging. The bipedal standing mice model can reflect the pathological characteristics of human HLF. The bipedal standing mice model can provide a standardized condition to elucidate the molecular mechanisms of mechanical stress‐induced HLF in vivo.

Integrative analysis of genome-wide DNA methylation and single-nucleotide polymorphism identified ACSM5 as a suppressor of lumbar ligamentum flavum hypertrophy

BackgroundHypertrophy of ligamentum flavum (HLF) is a common lumbar degeneration disease (LDD) with typical symptoms of low back pain and limb numbness owing to an abnormal pressure on spinal nerves. Previous studies revealed HLF might be caused by fibrosis, inflammatory, and other bio-pathways. However, a global analysis of HLF is needed severely.MethodsA genome-wide DNA methylation and single-nucleotide polymorphism analysis were performed from five LDD patients with HLF and five LDD patients without HLF. Comprehensive integrated analysis was performed using bioinformatics analysis and the validated experiments including Sanger sequencing, methylation-specific PCR, qPCR and ROC analysis. Furthermore, the function of novel genes in ligamentum flavum cells (LFCs) was detected to explore the molecular mechanism in HLF through knock down experiment, overexpression experiment, CCK8 assay, apoptosis assay, and so on.ResultsWe identified 69 SNP genes and 735 661 differentially methylated sites that were enriched in extracellular matrix, inflammatory, and cell proliferation. A comprehensive analysis demonstrated key genes in regulating the development of HLF including ACSM5. Furthermore, the hypermethylation of ACSM5 that was mediated by DNMT1 led to downregulation of ACSM5 expression, promoted the proliferation and fibrosis, and inhibited the apoptosis of LFCs.ConclusionThis study revealed that DNMT1/ACSM5 signaling could enhance HLF properties in vitro as a potential therapeutic strategy for HLF.

Lumbar ligamentum flavum burden: Evaluating the role of ATTRwt amyloid deposition in ligamentum flavum thickness at all lumbar levels

BackgroundWild-type transthyretin (ATTRwt) amyloid deposition has been found in the ligamentum flavum (LF) of patients undergoing spinal stenosis surgery. Our group previously reported that ATTRwt amyloid is associated with an increased lumbar ligamentum flavum thickness at symptomatic levels that required surgery. A comprehensive evaluation of LF thickness at asymptomatic levels in addition to symptomatic, treated levels has never been performed in ATTRwt patients. In this study, we compare the total LF thickness of all lumbar levels (lumbar LF burden) in ATTRwt and non-ATTRwt patients. MethodsWe retrospectively identified 177 patients who underwent lumbar spine surgery. Ligamentum flavum thickness of 885 lumbar levels was measured on T2-weighted axial MRI. Amyloid presence was confirmed through Congo red staining of specimens, and subtype of ATTRwt was confirmed using mass-spectrometry and gene sequencing. ResultsOf the 177 patients, 30 (16.9%) were found to have ATTRwt in the ligamentum flavum. One hundred and fifty ATTRwt levels and 735 non-ATTRwt levels were measured by four different reviewers, with an intraclass coefficient (ICC) of 0.79. Mean ligamentum flavum thickness was 4.64 (±1.31) mm in the ATTRwt group and 3.99 (±1.45) mm in the non-ATTRwt group (p < 0.001). The lumbar LF burden (sum of ligamentum flavum thickness at all lumbar levels) for ATTRwt patients was 23.22 (±4.48) mm, and for non-ATTRwt patients was 19.96 (±5.49) mm (p = 0.003) ConclusionThe lumbar LF burden is greater in patients with ATTRwt amyloid compared to non-ATTRwt patients. This supports prior evidence that ATTRwt amyloid deposition might be associated with increased LF thickness and lumbar stenosis. This potential association requires more research and could be an important finding, as medications have recently become available that can treat patients with ATTRwt amyloid deposition.

Apolipoprotein AI amyloid deposits in the ligamentum flavum in patients with lumbar spinal canal stenosis

Amyloidosis is a protein-misfolding disease characterised by insoluble amyloid deposits in the extracellular space of various organs and tissues, such as the brain, heart, kidneys, and ligaments. We previously reported the frequent occurrence of amyloid deposits in the ligament flavum in the presence of lumbar spinal canal stenosis (LSCS), which is a common spinal disorder in older individuals. Our earlier clinicopathological studies revealed that amyloid deposits derived from transthyretin (TTR) were involved in the pathogenesis of LSCS. ATTR amyloid was the most common form in the ligamentum flavum, but amyloid deposits that were not identified still existed in more than 50% of patients with LSCS. In this study, we found apolipoprotein AI (AApoAI) amyloid deposits in the ligamentum flavum of patients with LSCS. The deposits occurred in 12% of patients with LSCS. Biochemical studies revealed that the amyloid deposits consisted mainly of full-length ApoAI. As a notable finding, the lumbar ligamentum flavum of patients who had LSCS with double-positive amyloid deposits—positive for both ATTR and AApoAI—was significantly thicker than that of patients who had LSCS with single-positive—that is, positive for either ATTR or AApoAI—amyloid deposits. We thus suggest that lumbar AApoAI amyloid formation may enhance the pathological changes of lumbar ATTR amyloidosis in patients with LSCS.

Ligamentum Flavum Cyst With Acute Onset Motor Deficit: A Literature Review and Case Series.

Ligamentum flavum cysts have been rarely described in the literature and are one of the rare causes of neural compression and canal stenosis. Very few cases of their association with neurologic deficits are reported to date, and association with acute onset weakness is even rarer. We report our experience with 3 cases of ligamentum flavum cyst that presented with acute onset weakness and also present a comprehensive literature review on lumbar ligamentum flavum cysts reported to date. All 3 patients had symptoms of severe neurogenic claudication and presented to us with acute onset of motor weakness in lower limbs. Ligamentum flavum cyst was located in the midline in 2 cases and laterally in 1 case. We performed excision of the cyst and decompression with fusion in 2 cases and decompression alone in 1 case. All 3 cases had significant improvement in their neurologic status postoperatively. Histopathological examination confirmed ligamentum flavum cyst in all 3 cases. We performed a PUBMED and EMBASE database search using the MeSH (Medical Subject Headings) terms "ligamentum flavum" and "cysts" for articles published to April 2019. We could identify 7 studies describing 20 cases of lumbar ligamentum flavum cysts with motor weakness in the literature. Only 1 case had been described with an acute onset of weakness. Ligamentum flavum cysts should remain in the differential diagnosis of a patient who has symptoms of lumbar canal stenosis and presents with acute onset of neurological deficits. Such patients have a good improvement with surgery.

Ultrasound-Guided Percutaneous Release Procedures in the Lumbar Ligamentum Flavum by Acupotomy: A Cadaveric study.

Objective This study aims to determine the methods of percutaneous release procedures in the lumbar ligamentum flavum (LF) under ultrasound guidance by acupotomy and provide an anatomical basis for intrusive treatment of lumbar disc herniation and lumbar spinal canal stenosis. Methods Twelve cadavers including 4 females and 8 males aged 60 to 90 years (73.42 ± 14.57 years), without formalin fixation, were selected. Guided by an ultrasound transducer, we punctured acupotomy to release lumbar LF in L3/L4, L4/L5, and L5/S1 segments. In the transverse-axis approach, the probe was placed transversely, while in the longitudinal-axis approach, the probe was placed longitudinally. The depth of needle penetration (A), the distance between the puncture point and spinous process (B), and the distance between the puncture point and sacral cornu (C) were measured on cadavers, and the depth of needle penetration (U-A), the distance between the puncture point and spinous process (U-B), and the angle for acupotomy (D) on ultrasound images were also measured. Statistical analyses were carried out using SPSS. Paired sample t-tests and homogeneity of variance tests and one-way analysis of variance (ANOVA) were performed. The Pearson correlation coefficients and linear correlation coefficients were calculated for the data obtained from ultrasound and cadaver measurements. Results No obvious blood vessels and nerves were observed in the puncture path, and the spinal dura was intact. There was no statistical difference between the left and right side measurements obtained from the ultrasound images and the cadavers. The penetration depth in the transverse-axis approach was less than that in the longitudinal-axis approach, and the angle of the needle in the transverse-axis approach was greater than that in the longitudinal-axis approach. The measured data for the transverse-axis approach for L3/L4, L4/L5, and L5/S1 segments showed that there were no differences in the needle angle, the depth of needle penetration, and the distance from the spinous process to the puncture point among the three segments. There was a strong correlation between the depth of needle penetration and the distance from the spinous process to the puncture point on the ultrasonic images and the cadavers on the path of acupotomy. Linear equation A = 2.02 + 0.83 ∗ U-A, R2 = 0.352; B = 1.37 + 0.71 ∗ U-B, R2 = 0.252, where A/B refers to the data measured on the cadavers and U-A/U-B refers to the data measured on the ultrasound images. Conclusion In this study, ultrasound guidance was applied, which better guaranteed the safety and feasibility of acupotomy therapy. Before performing the treatment, the depth of needle penetration in the human body can be determined by measuring the distance between the needle point and the target position on the ultrasound image. Under ultrasound guidance, the transverse-axis approach has a smaller puncture depth and greater puncture angle than the longitudinal-axis approach. Hence, this study believes that the transverse-axis approach is safer for the clinical application of ultrasound-guided LF acupotomy lysis.

The Lumbar Ligamentum Flavum Does Not Have Two Layers and Is Confluent with the Interspinous Ligament: Anatomical Study with Application to Surgical and Interventional Pain Procedures

Numerous authors over the years have reported that the lumbar ligamentum flavum has two layers. Our routine cadaveric dissections raised the question whether this understanding is correct, as we always have observed only one layer. Thus, the goal of this cadaveric study was to reevaluate the layers of the ligamentum flavum. Twenty lumbar levels from five fresh-frozen cadaveric specimens were used in this study. After dissection of the lumbar spine, the ligamentum flavum and interspinous ligament were exposed. Each lumbar level was transected through the zygapophyseal joint, and hematoxylin and eosin staining, Masson's trichrome staining and Verhoeff-van Gieson staining were performed. Continuation of the interspinous ligament and ligamentum flavum were observed invariably. There was no evidence of the existence of a two-layered ligamentum flavum. The lumbar ligamentum flavum does not consist of two layers, but is confluent instead with the interspinous ligament that attaches to the zygapophyseal joints. To convey this anatomy better, we suggest describing the lumbar ligamentum flavum as a structure that consists of interlaminar and interspinous parts. Precise knowledge of the ligamentum flavum's anatomy can be of clinical value, particularly when epidural anesthesia or lumbar puncture are performed. Clin. Anat. 32:34-40, 2019. © 2019 Wiley Periodicals, Inc.

Mechanism of p38 mitogen activated protein kinase signaling pathway on promoting the hypertrophy of human lumbar ligamentum flavum via transforming growth factor β 1/connective tissue growth factor

To investigate the mechanism of p38 mitogen activated protein kinase (MAPK) signaling pathway in regulating the hyperplasia and hypertrophy of human lumbar ligamentum flavum via transforming growth factor β 1 (TGF-β 1)/connective tissue growth factor (CTGF). The lumbar ligamentum flavum tissue taken from patient with lumbar intervertebral disc herniation was isolated by collagenase-predigested explant cultures. The ligamentum flavum cells were treated with the extracellular regulated protein kinase pathway blocker PD98059, c-Jun N-terminal kinase pathway blocker SP600125, and p38 pathway blocker SB203580, and then the mRNA expressions of CTGF, collagen type Ⅰ, and collagen type Ⅲ were detected by real-time fluorescence quantitative PCR (qRT-PCR). The ligamentum flavum cells were divided into 4 groups, and transfected with small interfering RNA (siRNA), p38 siRNA, siRNA+3 ng/mL TGF-β 1, and p38 siRNA+3 ng/mL TGF-β 1 in groups A, B, C, and D, respectively. After 24 hours of transfection, immunofluorescence staining was performed to observe the expressions of p38 and phosphorylation p38 (p-p38); the relative mRNA expressions of CTGF, collagen type Ⅰ, and collagen type Ⅲ in each group were detected by qRT-PCR; the protein expression of CTGF in each group was detected by Western blot. p38 pathway blocker SB203580 could significantly reduce the relative mRNA expressions of CTGF, collagen type Ⅰ, and collagen type Ⅲ ( P<0.05). After 24 hours of transfection, immunofluorescence staining showed positive staining with p38 and p-p38 expressions in groups A, C, and D and negative staining in group B. Compared with group A, the relative mRNA expressions of CTGF, collagen type Ⅰ, and collagen type Ⅲ and relative protein expression of CTGF in group B decreased significantly ( P<0.05), while those in groups C and D increased significantly ( P<0.05); and those indicators significantly increased in group C than in group D ( P<0.05). TGF-β 1/CTGF based on the p38 MAPK signaling pathway play an important role in the occurance and development of hypertrophy of human lumbar ligamentum flavum.

Intraoperative video in a patient with lumbar ligamentum flavum hematoma (case 3): after insertion the endoscope into the hematoma cavity, we could find slight bleeding

Intraoperative video in a patient with lumbar ligamentum flavum hematoma (case 3): after insertion the endoscope into the hematoma cavity, we could find slight bleeding

Intraoperative video in a patient with lumbar ligamentum flavum hematoma (case 2): after insertion the endoscope into the hematoma cavity, we could find slight bleeding

Intraoperative video in a patient with lumbar ligamentum flavum hematoma (case 2): after insertion the endoscope into the hematoma cavity, we could find slight bleeding

Successful treatment of lumbar ligamentum flavum hematoma using a spinal full-endoscopic system.

Percutaneous endoscopic lumbar discectomy (PELD) is a relatively less invasive treatment for lumbar disc herniation (LDH). This study investigated the usefulness of a full-endoscopic system for PELD in lumbar ligamentum flavum hematoma (LFH) treatment. Between May 2017 and Jun 2018, a total of five patients with leg pain due to LFH underwent surgery using a full-endoscopic system for PELD. A percutaneous endoscopic translaminar approach (PETA) was performed right above the LFH. Pathological examination of the hematoma capsule was performed in all cases. The mean age of the patients was 64 years; there were 3 male and 2 female patients. Leg pain improved immediately after operation in all cases. Intraoperative findings and pathological examination revealed that the synovium at adjacent facet joints was not involved. Full-endoscopic system is not only a safe and effective minimally invasive system for the treatment of lumbar LFH, but is also superior to acquire a correct diagnosis.

MiR-615-3p inhibits the osteogenic differentiation of human lumbar ligamentum flavum cells via suppression of osteogenic regulators GDF5 and FOXO1.

Ossification of the ligamentum flavum (OLF) is a disease of heterotopic ossification in spinal ligaments. The key of the OLF pathogenesis is the differentiation of fibroblasts into osteoblasts. In this study, we explored the role of miR-615-3p in the osteogenic differentiation of human LF cells. The expression of miR-615-3p was detected during the osteogenic differentiation of hFOB1.19 human osteoblasts, human BMSCs, and human LF cells. The qPCR results showed that miR-615-3p was being decreased during the osteogenic differentiation of these cell lineages. Then, both gain- and loss-function experiments, respectively performed by single-strand miR-615-3p mimic and antagomir, revealed that miR-615-3p negatively regulated the osteogenesis of hLF cells, manifested by a lighter staining degree with Alizarin Red and a decreased level of osteogenic marker genes, including alkaline phosphatase (ALP), RUNX2, osterix (ostx), osteocalcin (OCN), and osteopontin (OPN). Subsequently, our data on bioinformatic analysis, 3'-UTR luciferase activity assay, and protein level detection indicated that miR-615-3p directly targeted and suppressed the expression of FOXO1 and GDF5. Furthermore, knockdown of either FOXO1 or GDF5 could inhibit the osteogenic differentiation of hLF cells, which displayed a similar effect with the miR-615-3p mimic. In conclusion, miR-615-3p negatively regulates the osteogenic differentiation of hLF cells through post-transcriptionally suppressing osteogenic regulators GDF5 and FOXO1. It can be regarded as a potential target for human OLF therapy.

Lumbar spinal canal stenosis complicated with lumbar ligamentum flavum cyst: a case report

Lumbar spinal canal stenosis complicated with lumbar ligamentum flavum cyst: a case report

Change of Lumbar Ligamentum Flavum after Indirect Decompression Using Anterior Lumbar Interbody Fusion.

Study DesignRetrospective case series.PurposeThe purpose of this study was to examine changes in the ligamentum flavum thickness and remodeling of the spinal canal after anterior fusion during a 10-year follow-up.Overview of LiteratureExtreme lateral interbody fusion provides minimally invasive treatment of the lumbar spine; this anterior fusion without direct posterior decompression, so-called indirect decompression, can achieve pain relief. Anterior fusion may restore disc height, stretch the flexure of the ligamentum flavum, and increase the spinal canal diameter. However, changes in the ligamentum flavum thickness and remodeling of the spinal canal after anterior fusion during a long follow-up have not yet been reported.MethodsWe evaluated 10 patients with L4 spondylolisthesis who underwent stand-alone anterior interbody fusion using the iliac crest bone. Magnetic resonance imaging was performed 10 years after surgery. The cross-sectional area (CSA) of the dural sac and the ligamentum flavum at L1–2 to L5–S1 was calculated using a Picture Archiving and Communication System.ResultsSpinal fusion with correction loss (average, 4.75 mm anterior slip) was achieved in all patients 10 years postsurgery. The average CSAs of the dural sac and the ligamentum flavum at L1–2 to L5–S1 were 150 mm2 and 78 mm2, respectively. The average CSA of the ligamentum flavum at L4–5 (30 mm2) (fusion level) was significantly less than that at L1–2 to L3–4 or L5–S1. Although patients had an average anterior slip of 4.75 mm, the average CSA of the dural sac at L4–5 was significantly larger than at the other levels.ConclusionsSpinal stability induced a lumbar ligamentum flavum change and a sustained remodeling of the spinal canal, which may explain the long-term pain relief after indirect decompression fusion surgery.

Cyclic stretch enhances apoptosis in human lumbar ligamentum flavum cells via the induction of reactive oxygen species generation

Objective: The lumbar ligamentum flavum (LF) is an important part of the spine to maintain the stability of the spine. In this study we aimed to examine whether mechanical force by cyclic stretch could induce apoptosis in human LF cells and investigate the underlying mechanism.Methods: LF cells were isolated from six young patients undergoing spinal surgery and then cultured in vitro. LF cells were subjected to cyclic stretch and the poptosis was detected by flow cytometry. The level of intracellular reactive oxygen species (ROS) and caspase-9 activity were measured.Results: Cyclic stretch at a frequency of 0.5 Hz with 20% elongation induced the apoptosis of human LF cells in vitro, and this was correlated with increased ROS generation and activation of caspase-9.Conclusion: Our study suggests that cyclic stretch-induced apoptosis in human LF cells may be mediated by ROS generation and the activation of caspase-9.