Study on the correlation between bony structural abnormalities and clinical symptoms in lumbar disc herniation

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.

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.

Cervical myelopathy resulting from combined ossification of the ligamentum flavum and posterior longitudinal ligament: report of two cases and literature review

Retrospective review. The aim of this study was to assess the clinical outcomes of surgery in patients with simultaneous ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF) at the same thoracic spine level and identify the risk factors for poor outcomes. OPLL complicated with OLF in the thoracic spine is a rare condition. The optimal treatment option for thoracic myelopathy due to OPLL and OLF remains controversial, and high risk of postoperative paralysis remains a major complication. We conducted a retrospective review of clinical and radiographic records of 15 patients who underwent surgery for simultaneous OPLL and OLF at the same level. Simultaneous OPLL and OLF occurred in the upper thoracic spine in 3 patients (20%), mid-thoracic spine in 10 patients (67%), and lower thoracic spine in 2 patients (13%). Six, 4, 2, and 3 patients underwent posterior decompression, posterior decompression and fusion, posterior decompression and circumferential decompression through a posterior approach, and circumferential decompression and posterior fusion, respectively. The mean Japanese Orthopaedic Association score before surgery and at the final follow-up was 5.7±1.9 and 7.0±2.1 points, respectively, yielding a mean recovery rate of 16.5%. However, no significant difference was observed between preoperative and postoperative Japanese Orthopaedic Association scores. Two patients with mid-thoracic lesions reported postoperative lower extremity weakness. Mid-thoracic lesions and considerable blood loss were risk factors for poor surgical outcome. Simultaneous OPLL and OLF in the mid-thoracic spine was observed in two thirds of the patients. We suggest that simultaneous OPLL and OLF in this area has a relatively poor recovery and may be very challenging and risky to treat, regardless of the surgical method selected, and recommend early surgery for OPLL and OLF in the mid-thoracic spine.

Study DesignRetrospective and comparative study.PurposeWe assessed surgical treatment outcomes in patients with thoracic myelopathy due to ossification of the ligamentum flavum (OLF), and OLF combined with ossification of the posterior longitudinal ligament (OPLL) or vertebral fracture (VF) at the same level.Overview of LiteratureOLF and OPLL cause severe thoracic myelopathy. Osteoporotic VF commonly occurs at the thoracolumbar junction. There have been no investigations of thoracic myelopathy due to OLF and VF.MethodsForty patients were divided among three groups: the OLF group (n=23): myelopathy due to OLF, the OLF+OPLL group (n=12): myelopathy due to OLF and OPLL, and the OLF+VF group (n=5): myelopathy due to OLF and VF. We recorded OLF, OPLL, and VF sites and operative procedures. Each patient’s neurological status, according to the Japanese Orthopaedic Association (JOA) score, and walking ability were evaluated pre- and postoperatively.ResultsPatients in the OLF+OPLL group were significantly younger than those in the other two groups. The preoperative JOA score was significantly lower in the OLF+VF than OLF group. The final JOA score was significantly lower in the OLF+VF than OLF and OLF+OPLL groups. The JOA score recovery rate was significantly lower in the OLF+VF than OLF group. Final walking ability was significantly worse in the OLF+OPLL and OLF+VF groups than in the OLF group and significantly worse in the OLF+VF than OLF+OPLL group.ConclusionsThoracic myelopathy due to OLF+VF occurs primarily in older females, who also exhibit worse preoperative and postoperative neurological status, and worse walking ability, than patients with thoracic myelopathy due to OLF or OLF+OPLL.

Association between intraoperative hypotension and motor evoked potential change in ossification of posterior longitudinal ligament and/or ossification of ligamentum flavum surgery

This study aimed to investigate the possible relationship between Scheuermann disease (SD) and the pathophysiological factors of thoracic spinal stenosis (TSS), including ossification of the ligamentum flavum (OLF), ossification of the posterior longitudinal ligament (OPLL), and thoracic disc herniation (TDH) in patients with symptomatic TSS. Demographic and radiological data from 66 consecutive patients diagnosed with symptomatic TSS from 2013 to 2018 were retrospectively collected and divided into 3 groups depending on the underlying pathomechanism of TSS: TDH group (18 patients; 6 women; mean age ± standard deviation [Sd] = 59.89 ± 11.34), OPLL group (12 patients; 8 women; mean age ± Sd = 56.08 ± 14.74), and OLF group (36 patients; 20 women; mean age ± Sd = 58.69 ± 9.77). A total of 41 age-matched healthy individuals (19 women; mean age ± Sd = 54.88 ± 13.63) were designated as the control group. In each group, both typical and atypical SD criteria were radiologically examined. The demographic data and presence of SD between the control group and 3 subgroups of TSS pathomechanisms were evaluated. SD characteristics were identified in 83.33% (15/18) of patients in the TDH group, 44.44% (16/36) in the OLF group, 25% (3/12) in the OPLL group, and 17.07% (7/41) of the control individuals. When analyzed by the chi-squared test and logistic regression analysis, the presence of SD was significantly associated with TDH (P < 0.01) and OLF (P < 0.05) but not OPLL (P > 0.05). Patients with TDH and OLF showed peak involvement of T10/11, and patients with OPLL did not. Furthermore, we determined that age, sex, body-mass index, and smoking status were not the risk factors for TDH, OPLL, and OLF (P > 0.05). SD was found to be a risk factor for TDH (P < 0.01) and OLF (P < 0.05) but not for OPLL (P > 0.05). Evidence from this study indicated that SD might be a risk factor for OLF and TDH but not for OPLL.

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

A case-control association study was conducted to investigate the genetic etiology for ossification of the ligamentum flavum (OLF) and ossification of the posterior longitudinal ligament of the spine (OPLL). To determine whether COL6A1 polymorphisms are associated with susceptibility to OLF and OPLL in Chinese Han population. The COL6A1 has been identified as a susceptibility gene for OPLL in Japanese. The susceptibility gene for OPLL may be different among various populations, so we investigated whether COL6A1 polymorphisms are also associated with OPLL in Chinese Han population. OLF and OPLL are similar in epidemiology, etiology, and pathology, and common coexist. Hereditary factors may be implicated in OLF and COL6A1 may be a potential susceptibility gene for OLF, so we investigated the relations between COL6A1 polymorphisms and OLF. Four known single nucleotide polymorphisms (SNPs) of COL6A1 were genotyped among 338 Chinese Han subjects by high throughput GenomeLab SNPstream genotyping system. Allele frequency and genotype distribution of each polymorphism were compared using a contingency chi2 test between 183 cases (90 OPLL, 61 OLF, and 32 OPLL coexisting with OLF) and 155 controls. Among 4 studied SNPs, allele frequency of promoter (-572T) SNP demonstrated the most significant difference not only between OPLL cases and controls (P = 2.65E-4), but also between OLF cases and controls (P =7.38E-4). Moreover, the overall frequency of haplotypes constructed from promoter (-572), intron 32 (-29), and intron 33 (+20) SNPs showed significant difference not only between the patients with OPLL and controls, but also between the patients with OLF and controls (P = 5.86E-3, P = 1.5E-8, respectively). This is the first report on SNPs of COL6A1 in OLF that suggests polymorphisms may be a risk factor for OLF. Our findings indicate that COL6A1 may be a common susceptibility gene for OLF and OPLL in Chinese Han population.

Background: Ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF) are multifactor diseases characterized by progressively ectopic ossification in the spinal ligament. However, the shared ossification mechanism of OPLL and OLF remains to be elucidated. The study aims to investigate the common biomarkers related to ectopic ossification and the potential molecular regulatory mechanism.Methods: Microarray and RNA-seq datasets were obtained from Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) from OPLL and OLF were identified to construct the protein-protein interaction (PPI) network. Furthermore, the hub intersection genes were screened and the diagnostic performance was assessed in the external OLF and OPLL cohorts. We also depicted the landscape of immune cell infiltration and m6A modification meanwhile further estimating the relationship with BMP4.Results: A total of nine up-regulated DEGs and 11 down-regulated DEGs were identified to construct the PPI networks. The integrative bioinformatic analysis defined five hub genes (BMP4, ADAMTS4, HBEGF, IL11, and HAS2) as the common risk biomarkers. Among them, BMP4 was the core target. ROC analysis demonstrated a high diagnostic value of the hub genes. Moreover, activated B cells were recognized as shared differential immune infiltrating cells and significantly associated with BMP4 in OPLL and OLF. Meanwhile, a strong correlation was detected between the expression pattern of the m6A regulator METTL3 and BMP4.Conclusion: This study first identified BMP4 as the shared core biomarker in the development of OPLL and OLF. Activated B cells and m6A writer METTL3 might be involved in the osteogenesis process mediated by BMP4. Our findings provide insights into the pathogenesis in the ossification of the spinal ligament and unveil the potential therapeutic targets.

Ossification of the Ligaments in the Cervical Spine, Including Ossification of the Anterior Longitudinal Ligament, Ossification of the Posterior Longitudinal Ligament, and Ossification of the Ligamentum Flavum

Retrospective study. The aim was to investigate the clinical outcomes in patients with thoracic myelopathy in a single institution and to identify prognostic factors for poor outcomes. Because of the rarity of thoracic myelopathy, a few studies have analyzed a large number of clinical results for patients with thoracic myelopathy treated in a single institution. Seventy-one patients who underwent surgical treatment for thoracic myelopathy between 2000 and 2011 in a single institution were included in this analysis. We investigated the patients' characteristics, surgical outcomes, and prognostic factors for poor outcomes. Of the 73 patients, eight patients had disc herniation (DH) or spinal stenosis (SS), 10 patients had ossification of the posterior longitudinal ligament (OPLL), 40 patients had ossification of the ligamentum flavum (OLF), and 15 patients had OPLL + OLF. The mean patient age at the time of surgery was 61.9 years. Thoracic myelopathy was caused by OPLL and/or OLF in 65 patients (89%). Fifty-eight patients underwent laminectomy, eight patients underwent laminectomy and posterior fusion, four patients underwent OPLL extirpation and posterior fusion, and three patients underwent OPLL extirpation. The mean Japanese Orthopedic Association Scoring System scores before surgery and at the final follow-up examination were 6.0 ± 1.8 and 7.7 ± 2.0 points, respectively, yielding a mean recovery rate of 30% ± 43%. The JOA score improved significantly postoperatively (P < 0.05). Risk factors for poor outcomes were longer preoperative symptom duration, preoperative JOA score < 7, and OPLL and/or OLF. Large blood loss volume was significantly associated with a worse postoperative JOA score. A considerable degree of neurological recovery was observed after surgical treatment in patients with thoracic myelopathy. Prognostic factors for poor outcomes were longer preoperative duration of symptoms, worse preoperative symptoms, OPLL and/or OLF, and large volume of intraoperative bleeding. 4.

Patients with ossification of the ligamentum flavum (OLF) in the lumbar spine may be at high risk of developing concomitant ossification of the entire spinal ligament, but the etiology remains unclear. We investigated the propensity for spinal ligament ossification in asymptomatic subjects with lumbar OLF using the data of 595 Japanese individuals receiving medical check-ups, including computed tomography (CT) scanning. The severity of OLF (total number of intervertebral segments with OLF) of the entire spine on CT was quantified using an OLF index. Subjects with OLF were grouped according to this index: localized OLF (n = 138), intermediate OLF (n = 70), and extensive OLF (n = 31). The proportion of subjects with lumbar OLF increased with increasing OLF index (localized 13.7%, intermediate 41.4%, and extensive 70.9%). Multiple regression analysis found that lumbar OLF index was associated with thoracic OLF index, and co-existence of ossification of the posterior longitudinal ligament (OPLL) of the thoracic and lumbar spine. This study showed that subjects with more multilevel lumbar OLF were more likely to develop multilevel thoracic OLF and to have coexisting OPLL. Patients with lumbar OLF may be a distinctive subgroup with a strong tendency to ossification of the entire spinal ligament.

Two-Staged Circumferential Decompression and Fusion Surgery for Upper Thoracic Myelopathy Caused by Concurrent Beak-Type Ossification of the Posterior Longitudinal Ligament and Ligamentum Flavum at T1-T2 Level: A Case Report

Background/Objectives: This study aims to develop and validate a YOLOv3-based deep learning model for detecting ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF) on lateral thoracic radiographs, improving early diagnosis and screening accessibility. Methods: A retrospective dataset of 356 lateral thoracic radiographs, including 176 with OPLL or OLF and 180 controls, was annotated by spine surgeons. The YOLOv3 model was trained using data augmentation and evaluated via five-fold cross-validation, with accuracy, precision, recall, and F1-score compared to two spine surgeons. Results: The model achieved 80.6% accuracy, 70.3% precision, 92.6% recall, and 79.9% F1-score, surpassing spine surgeons in accuracy and recall, especially for combined OPLL and OLF cases. Detection accuracy was 81.1% for OPLL, 53.3% for OLF, and 86.3% for combined cases. Conclusions: The YOLOv3-based model provides high accuracy and robust detection of OPLL and OLF on plain radiographs, offering an efficient and accessible screening tool.