Ossification Of The Posterior Longitudinal Ligament Group Research Articles

Association between Congestive Heart Failure and Ossification of the Posterior Longitudinal Ligament in Korea: A Nationwide Longitudinal Cohort Study

Objective: The objective of this nationwide, long-term follow-up study was to explore the connection between congestive heart failure (CHF) and ossification of the posterior longitudinal ligament (OPLL) in Korea.Methods: Patient information was collected from the Health Screening cohort of the National Health Insurance Service. Individuals diagnosed with OPLL were identified using specific International Classification of Diseases, 10th revision codes (M48.8, M48.81, M48.82, and M48.83). A total of 1,289 OPLL patients and 6,445 controls were included in the study, selected through 1:5 age and sex matching. The data spanned from January 1, 2004 to July 31, 2015. To compute the incidence rate of CHF in each group, the Kaplan-Meier method was employed. Additionally, Cox proportional-hazards regression analysis was utilized to estimate the hazard ratio of CHF.Results: CHF was present in 19 patients (1.47%) in the OPLL group and 71 patients (1.10%) in the control group. After accounting for age and sex, the hazard ratio for CHF in the OPLL group was 3.164 (95% confidence interval [CI], 1.867-5.360). When additionally considering income and underlying diseases, the hazard ratio for CHF within the OPLL group was 3.355 (95% CI, 1.977-5.694). All subgroups of OPLL patients exhibited an increased risk ratio for CHF across parameters such as sex, age, diabetes, hypertension, and dyslipidemia.Conclusion: According to this nationwide longitudinal study, an elevated incidence rate of CHF was associated with OPLL.

MRI-based vertebral bone quality score in cervical ossification of the posterior longitudinal ligament: a comparison with cervical spondylotic myelopathy using propensity score matching

BACKGROUNDBone mineral density plays a key role in the assessment of operative instrumentation complications and clinical outcomes. The MRI-based vertebral bone quality (VBQ) score has been introduced as a novel marker of bone quality. However, few studies have investigated the relationship between VBQ score and patients associated with cervical ossification of the posterior longitudinal ligament (OPLL). PURPOSEThe aims of the study were (1) to reveal bone mineral density between cervical OPLL and cervical spondylotic myelopathy (CSM) group by VBQ score, (2) to compare the VBQ score of cervical OPLL between male and female group, (3) to explore the relationship between segmental VBQ scores associated with OPLL. STUDY DESIGNRetrospective cohort study. PATIENT SAMPLEConsecutive series of 425 patients at a single academic institution. OUTCOME MEASURESMRI based measurements of C2–C7 VBQ scores. METHODSPreoperative noncontrast T1-weighted MRIs of the cervical spine was used to measure the VBQ score. The VBQ score was defined as the mean value of the signal intensity of the vertebrae divided by that of the cerebrospinal fluid (CSF) space at the cisterna magna. Patients with cervical OPLL and CSM were matched based on age, sex, body mass index (BMI), comorbidity, medication history, diet habit, smoking, alcohol consumption via propensity score matching (PSM). Normality of each VBQ score was tested by the Shapiro-Wilk test. Wilcoxon's rank-sum test was used to compare matched cohorts. Kruskal-Wallis test was performed to compare the VBQ scores between segments. Multivariate logistic regression analysis was used to evaluate factors associated with the development of cervical OPLL. RESULTSA total of 425 patients were assessed. For final analysis, 135 paired patients were compared between the cervical OPLL and CSM groups, and 22 paired patients were compared between male and female group associated with cervical OPLL. There were no statistically significant differences in age, sex, BMI, comorbidity, medication history, diet habit, smoking, alcohol between the matched cohorts. OPLL group was associated with lower VBQ score compared with CSM group at C3, while there were no differences in VBQ score for the other levels between the two groups. There were no differences between male and female group associated with OPLL in C2–C7 VBQ scores. VBQ scores of cervical OPLL are variable between segments, with significantly lower scores at C6, C7 compared with C1–C5. Multivariate logistic regression analysis showed that BMI was correlated with the development of OPLL (regression coefficient, 0.162; 95% confidence interval, 0.010–0.037). Additional risk factors included hypertension, calcium supple history and smoking. CONCLUSIONSThis study demonstrates that cervical OPLL is associated with lower VBQ score at C3, with no differences for the other levels when compared with CSM derived from measurements on MRI. No differences were found between male and female group associated with OPLL in C2–C7 VBQ scores. Cervical OPLL were found to have smaller VBQ score at C6, C7 compared with C1–C5. Our findings provide new insight for bone density assessment in cervical OPLL patient.

MRI-based lesion quality score assessing ossification of the posterior longitudinal ligament of the cervical spine

BACKGROUND CONTEXTNo method currently exists for MRI-based determination of ossification of the posterior longitudinal ligament (OPLL) of the cervical spine using objective criteria. PURPOSEThe purpose of this study was to develop an MRI-based score to determine whether a lesion represents a cervical OPLL lesion and to establish the objective diagnostic value. STUDY DESIGNRetrospective cohort in a single medical institution. PATIENT SAMPLEThirty-five patients undergoing surgery for OPLL (Group A) and 99 patients undergoing cervical disc arthroplasty for soft disc herniation (Group B) between 2011 and 2020 were retrospectively included. All OPLL lesions on unenhanced MRI scan were correlated with a corresponding CT scan. Demographics were comparable between the two groups. OUTCOME MEASURES (PHYSIOLOGIC MEASURES)Using unenhanced magnetic resonance imaging (MRI), the T1- and T2- lesion quality (LQ) scores were calculated. Receiver operating characteristic (ROC) analysis was performed to calculate the area-under-the-curve (AUC) of both LQ scores as a predictor of the presence of OPLL. Computed tomography (CT)-based Hounsfield unit (HU) values of OPLL lesions were obtained and compared with both LQ scores. The LQ scores for MRI scanners from different manufacturers were compared using Student's t test to confirm the validity of the LQ score by scanner type. METHODSThe regions of interest for signal intensity (SI) were defined as the darkest site of the lesion and the cerebrospinal fluid (CSF) at the cerebellomedullary cistern. The T1 and T2 LQ scores were measured as the ratio of the SI at the darkest site of the lesion divided by the SI of the CSF. RESULTSThe T1 and T2 LQ scores in Group A were significantly lower than those in Group B (p<.001). ROC analysis determined that T1 and T2 LQ scores of 0.46 and 0.07, respectively, could distinguish the presence of OPLL with an accuracy of 0.93 and 0.89, respectively (p<.001). When the T1 LQ score of the lesion is <0.46, a diagnosis of OPLL may be suspected with 100% sensitivity and 92.3% specificity. The HU of the lesion had a moderate negative correlation with the T1 LQ score (r=−0.665, p<.0001). Both LQ scores were unaffected by manufacturer type. CONCLUSIONSThis study found a correlation between the MRI-based T1 LQ scores and CT-based HU value for identifying OPLL lesions. Additional studies will be needed to validate that the T1 LQ score from the unenhanced MRI scan can identify cervical OPLL.

Validating the preoperative Japanese Core Outcome Measures Index for the Neck and comparing quality of life in patients with cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament by the patient-reported outcome measures.

This cross-sectional study serves two main purposes. Firstly, it aims to validate the preoperative Japanese Core Outcome Measures Index for the Neck (COMI-Neck) in patients with cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL). Secondly, it seeks to elucidate differences in preoperative quality of life (QOL) between these two cervical pathologies using patient-reported outcome measures (PROMs). A total of 103 preoperative patients (86 with CSM and 17 with OPLL) scheduled for cervical spine surgery were included in the study. Validated PROMs, including the Japanese COMI-Neck, Neck Disability Index (NDI), EuroQol-5 Dimension-3 level (EQ-5D-3L), and SF-12v2, were used to assess QOL. Baseline demographic and clinical data were collected, and statistical analyses were performed to compare the PROMs between CSM and OPLL groups. The Japanese COMI-Neck demonstrated good construct validity, with positive correlations with NDI and negative correlations with EQ-5D-3L and SF-12v2. Comparison of preoperative PROMs between CSM and OPLL groups revealed differences in age, body mass index, and EQ-5D-3L scores. The CSM group had higher NDI scores for concentration and lower EQ-5D-3L scores for self-care compared to the OPLL group. This study validated the preoperative Japanese COMI-Neck in CSM and OPLL patients and identified specific QOL issues associated with each condition. The findings highlight the importance of considering disease-specific QOL and tailoring treatment plans accordingly. Further research should include postoperative assessments and a more diverse population to enhance generalizability.

Association between serum interleukin-17 levels and ectopic bone formation in OPLL patients with DISH.

To investigate the relationship between the severity and morphology of heterotopic ossification in the spinal ligaments including sacroiliac (SI) joints, and serum interleukin-17 (IL-17) levels in patients with ossification of the posterior longitudinal ligament (OPLL) with or without diffuse idiopathic skeletal hyperostosis (DISH), as well as a non-OPLL group. A total of 103 patients with OPLL (DISH (-), n = 50; DISH (+), n = 53) and 53 age- and gender-matched controls were included. The serum levels of IL-17 were analyzed, and the severity of ectopic ossification and the morphology of ectopic bone formation were evaluated. The SI joint morphological variations were categorized into four types. No significant differences were found in serum IL-17 levels between the OPLL and control groups. However, the DISH (+) group showed higher IL-17 levels than the DISH (-) group, especially in female patients (p = 0.003). Additionally, IL-17 levels were positively correlated with the number of Flat vertebral units, meaning one of the characteristics of DISH ossification type (R2 = 0.199, p = 0.012). IL-17 levels in type 4 were significantly higher in the DISH (+) group than in the DISH (-) group. The morphological characteristics of paravertebral bone formation in the entire spine, including the SI joint, are likely associated with serum IL-17 levels in OPLL. These findings provide pathological and serological evidence of local inflammation contributing to paravertebral ossification of OPLL patients.

Comparative Study of the Cytokine Profiles of Serum and Tissues from Patients with the Ossification of the Posterior Longitudinal Ligament.

The ossification of the posterior longitudinal ligament (OPLL) is one of the contributing factors leading to severe cervical spondylotic myelopathy (CSM). The mechanism causing ossification is still unclear. The current study was designed to analyze the specimens of patients with or without OPLL. The study collected 51 patients with cervical spondylosis. There were six serum samples in both the non-OPLL (NOPLL) and OPLL groups. For tissue analysis, there were seven samples in the NOPLL group and five samples in the OPLL group. The specimens of serum and tissue were analyzed by using Human Cytokine Antibody Arrays to differentiate biomarkers between the OPLL and NOPLL groups, as well as between serum and OPLL tissue. Immunohistochemical staining of the ligament tissue was undertaken for both groups. For OPLL vs. NOPLL, the serum leptin levels are higher in the OPLL group, corroborating others' observations that it may serve as a disease marker. In the tissue, angiogenin (ANG), osteopontin (OPN), and osteopro-tegerin (OPG) are higher than they are in the OPLL group (p < 0.05). For serum vs. OPLL tissue, many chemotactic cytokines demonstrated elevated levels of MIP1 delta, MCP-1, and RANTES in the serum, while many cytokines promoting or regulating bone genesis were up-regulated in tissue (oncostatin M, FGF-9, LIF, osteopontin, osteoprotegerin, TGF-beta2), as well as the factor that inhibits osteoclastogenesis (IL-10), with very few cytokines responsible for osteoclastogenesis. Molecules promoting angiogenesis, including angiotensin, vEGF, and osteoprotegerin, are abundant in the OPLL tissue, which paves the way for robust bone growth.

High whole-body bone mineral density in ossification of the posterior longitudinal ligament

BACKGROUND CONTEXTRecent studies suggest that ossification of the posterior longitudinal ligament (OPLL) is exacerbated by systemic metabolic disturbances, including obesity. However, although an increase in bone mineral density (BMD) measured at the lumbar spine has been reported in patients with OPLL, no studies have investigated the systemic BMD of patients with OPLL in detail. PURPOSEWe investigated whether patients with OPLL develop increased whole-body BMD. STUDY DESIGNSingle institution cross-sectional study. PATIENT SAMPLEData were collected from Japanese patients with symptomatic OPLL (OPLL [+]; n=99). Control data (OPLL [-]; n=226) without spinal ligament ossification were collected from patients who underwent spinal decompression, spinal fusion, or hip replacement surgery. OUTCOME MEASURESDemographic data, including age, body mass index (BMI), comorbidities, history of treatment for osteoporosis, and history of vertebral and nonvertebral fractures, was obtained from all participants. In addition, whole-body BMD, including the lumbar spine, thoracic spine, femoral neck, skull, ribs, entire upper extremity, entire lower extremity, and pelvis, were measured in all participants using whole-body dual-energy X-ray absorptiometry. METHODSPatient data were collected from 2018 to 2022. All participants were categorized based on sex, age (middle-aged [<70 years] and older adults [≥70 years]), and OPLL type (localized OPLL [OPLL only in the cervical spine], diffuse OPLL [OPLL in regions including the thoracic spine]), and OPLL [-]) and each parameter was compared. The factors associated with whole-body BMD were evaluated via multivariable linear regression analysis. RESULTSCompared with the OPLL (-) group, the OPLL (+) group of older women had significantly higher BMD in all body parts (p<.01), and the OPLL (+) group of older men had significantly higher BMD in all body parts except the ribs, forearm, and skull (p<.01). The factors associated with increased BMD of both the femoral neck (load-bearing bone) and skull (nonload-bearing bone) were age, BMI, and coexisting diffuse OPLL in women and BMI and coexisting localized OPLL in men. CONCLUSIONSPatients with OPLL have increased whole-body BMD regardless of sex, indicating that it is not simply due to load-bearing from obesity. These findings suggested that OPLL is associated with a systemic pathology.

Comparative study of preoperative sagittal alignment between patients with multisegment cervical ossification of the posterior longitudinal ligament and cervical spondylotic myelopathy

BACKGROUND CONTEXTPreoperative sagittal alignment is of great significance in the development of spinal deformities, degenerative diseases, preoperative planning, postoperative clinical evaluation, and functional recovery. However, few reports have focused on the difference in preoperative sagittal alignment between patients with ossification of the posterior longitudinal ligament (OPLL) and patients with cervical spondylotic myelopathy (CSM). PURPOSETo compare preoperative sagittal alignment between patients with multisegment cervical OPLL and multilevel CSM. STUDY DESIGNRetrospective study. PATIENT SAMPLEA total of 243 patients were included in this study. OUTCOME MEASURESThe outcome measures were the Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS) score, number of hand actions in 10 seconds, hand-grip strength, C2 to C7 Cobb angle, C2 to C5 Cobb angle, C5 to C7 Cobb angle, C2 to C7 sagittal vertical axis, C7 slope, T1 slope, K-line, K-line tilt, and range of motion (ROM). METHODSThe outcome measures were calculated in the OPLL group and CSM group and the data were analyzed using the unpaired t-test, χ² test, and one-way analysis of variance. RESULTSA total of 243 patients (136 men, 107 women; mean age, 59.1±10.6 years) underwent surgical treatment from September 2013 to December 2021. In total, 123 patients were diagnosed with multisegment cervical OPLL, including continuous type (n=39), segmental type (n=38), and mixed type (n=46). The remaining 120 patients had multisegment CSM. The disease course in the OPLL group was significantly shorter than that in the CSM group (p<.05). Among the above preoperative measurements, the JOA score, number of hand actions in 10 seconds, hand-grip strength, and VAS score were not significantly different between the two groups (p>.05). The C2 to C7 Cobb angle was significantly larger in the OPLL than CSM group (17.7°±9.2° and 14.9°±9.3°, respectively; p< .05), as was the C5 to C7 Cobb angle (10.0°±6.3° and 7.5°±6.1°, respectively; p<.05). The ROM was significantly smaller in the OPLL than CSM group (33.1°±8.1° and 40.1°±10.9°, respectively; p<.001). Within the OPLL group, the ROM was significantly smaller in the continuous type than in the segmental type (p<.05). CONCLUSIONPatients with multisegment cervical OPLL have greater lordotic preoperative sagittal alignment and smaller preoperative ROM than patients with CSM.

Dyslipidemia as a novel risk for the development of symptomatic ossification of the posterior longitudinal ligament

BACKGROUND CONTEXTObesity and visceral fat have been implicated as potential factors in the pathogenesis of the ossification of the posterior longitudinal ligament (OPLL); the details of the factors involved in OPLL remain unclear. PURPOSEWe aimed to determine the association between dyslipidemia and symptomatic OPLL. STUDY DESIGNSingle institution cross-sectional study. PATIENT SAMPLEData were collected from Japanese patients with OPLL (n=92) who underwent whole-spine computed tomography scanning. Control data (n=246) without any spinal ligament ossification were collected from 627 Japanese participants who underwent physical examination. OUTCOME MEASURESBaseline information and lipid parameters, including triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) from fasting blood samples were collected to assess the comorbidity of dyslipidemia. METHODSPatient data were collected from 2020 to 2022. Patients with dyslipidemia were defined as those who were taking medication for dyslipidemia and who met one of the following criteria: TG ≥150 mg/dL, LDL-C ≥140 mg/dL, and/or HDL-C <40 mg/dL. The factors associated with OPLL development were evaluated using multivariate logistic regression analysis. RESULTSThe comorbidity of dyslipidemia in the OPLL group was more than twice that in the control group (71.7% and 35.4%, respectively). The mean body mass index (BMI) of the OPLL group was significantly higher than that of the control group (27.2 kg/m2 and 23.0 kg/m2). Multivariate logistic regression analysis revealed that dyslipidemia was associated with the development of OPLL (regression coefficient, 0.80; 95% confidence interval, 0.11–1.50). Additional risk factors included age, BMI, and diabetes mellitus. CONCLUSIONSWe demonstrated a novel association between dyslipidemia and symptomatic OPLL development using serum data. This suggests that visceral fat obesity or abnormal lipid metabolism are associated with the mechanisms of onset and exacerbation of OPLL as well as focal mechanical irritation due to being overweight.

Association of Acute Myocardial Infarction with Ossification of the Posterior Longitudinal Ligament in Korea: A Nationwide Longitudinal Cohort Study

Objective: This nationally matched longitudinal study aimed to investigate the relationship between acute myocardial infarction (AMI) and ossification of the posterior longitudinal ligament (OPLL) in Korea.Methods: We collected patient data from January 1, 2004 to December 31, 2015 from the National Health Insurance Service Health Screening Cohort. Patients with OPLL were defined as patients with the International Classification of Diseases, Tenth Revision code M48.8 (other specified spondylopathies) and were newly diagnosed through computed tomography imaging. The OPLL group had a total of 1,289 patients. The control group included 6,445 people. Utilizing the Kaplan-Meier technique, The incidence of AMI in both groups was estimated. A Cox proportional-hazards regression analysis was used to compute the AMI hazard ratio.Results: After controlling for age and sex, the hazard ratio of AMI in the OPLL group was 2.065 (95% confidence interval [CI], 1.228-3.474). The adjusted hazard ratio in the OPLL group was 2.209 after restricting the sample for demographics and concomitant medical conditions (95% CI, 1.311-3.721). In a subgroup analysis, the incidence of AMI was substantially greater in the OPLL group, which included women younger than 65 years and without hypertension, diabetes, or dyslipidemia.Conclusion: This nationwide longitudinal study found that patients with OPLL were at higher risk of AMI.

Regulatory Mechanism between Ferritin and Mitochondrial Reactive Oxygen Species in Spinal Ligament-Derived Cells from Ossification of Posterior Longitudinal Ligament Patient.

Primary spinal ligament-derived cells (SLDCs) from cervical herniated nucleus pulposus tissue (control, Ctrl) and ossification of the posterior longitudinal ligament (OPLL) tissue of surgical patients were analyzed for pathogenesis elucidation. Here, we found that decreased levels of ferritin and increased levels of alkaline phosphatase (ALP), a bone formation marker, provoked osteogenesis in SLDCs in OPLL. SLDCs from the Ctrl and OPLL groups satisfied the definition of mesenchymal stem/stromal cells. RNA sequencing revealed that oxidative phosphorylation and the citric acid cycle pathway were upregulated in the OPLL group. SLDCs in the OPLL group showed increased mitochondrial mass, increased mitochondrial reactive oxygen species (ROS) production, decreased levels of ROS scavengers including ferritin. ROS and ferritin levels were upregulated and downregulated in a time-dependent manner, and both types of molecules repressed ALP. Osteogenesis was mitigated by apoferritin addition. We propose that enhancing ferritin levels might alleviate osteogenesis in OPLL.

Strong relationship between dyslipidemia and the ectopic ossification of the spinal ligaments

Obesity and metabolic disturbances are prevalent in ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF); however, the involvement of dyslipidemia (DL) in OPLL/OLF remains uncertain. We investigated the association between dyslipidemia and OPLL/OLF using a dataset of 458 individuals receiving health screening tests, including computed tomography. Subjects were grouped according to the presence or location of OPLL/OLF: controls (no OPLL/OLF, n = 230), OLF (n = 167), cervical OPLL (n = 28), and thoracic OPLL (n = 33). They were also grouped according to the presence of dyslipidemia (DL[+], n = 215; DL[−], n = 243). The proportion of dyslipidemia in the OLF and OPLL groups was 1.6–2.2 times higher than that in the control group. The proportion of OLF and OPLL in the DL(+) group was significantly higher than that in the DL(−) group (OLF, 43% vs. 29%; cervical OPLL, 14.4% vs. 3.2%; thoracic OPLL, 11.1% vs. 3.7%). Multivariate logistic regression analysis showed an association between all ossification types and dyslipidemia. This study demonstrated an association of dyslipidemia with OPLL/OLF; further investigation on the causal relationship between dyslipidemia and ectopic spinal ligament ossification is warranted to develop a therapeutic intervention for OPLL/OLF.

Noninvasive Skin Autofluorescence of Advanced Glycation End Products for Detecting Ossification of the Posterior Longitudinal Ligament in the Thoracic Spine.

A single-center prospective observational study. The aim was to clarify the usefulness of assessing advanced glycation end products (AGEs) by noninvasive skin autofluorescence in patients with ossification of the posterior longitudinal ligament (OPLL). AGE accumulation is associated with various systemic disorders, including aging, diabetes mellitus, and obesity. AGEs have also been associated with OPLL, but their assessment by noninvasive skin autofluorescence has not been yet studied in these patients. We enrolled patients with degenerative spinal spondylosis and divided them into non-OPLL and OPLL groups. The OPLL group was further subdivided into cervical OPLL (C-OPLL) and thoracic OPLL (T-OPLL) groups. We compared patients' characteristics, serum laboratory data (i.e. hemoglobin A1c, total cholesterol, creatinine, and estimated glomerular filtration rate), and the skin autofluorescence intensity of AGEs (the AGE score) between the non-OPLL and OPLL groups and among the non-OPLL, C-OPLL, T-OPLL groups. Finally, the association of the AGE score with the presence of C-OPLL or T-OPLL was assessed by multinomial logistic regression. Among the 240 eligible patients, 102 were in the non-OPLL group and 138 were in the OPLL group (92 with C-OPLL and 46 with T-OPLL). We observed no significant difference in the AGE score between the non-OPLL and OPLL groups, but when comparing the score among the non-OPLL, C-OPLL, and T-OPLL groups, we found that the T-OPLL group had a significantly higher AGE score. The results of multinomial regression analysis showed that a higher AGE score was significantly associated with T-OPLL (odds ratio: 1.46; 95% CI: 1.01-2.11; P=0.044). The AGE score determined by noninvasive skin autofluorescence could help to screen for OPLL in the thoracic spine.

Diagnostic accuracy of cervical spine imaging to predict thoracic ossification of the posterior longitudinal ligament: Retrospective chart review

PurposeTo analyze the significance of ossification index of cervical posterior longitudinal ligament as a risk factor for thoracic OPLL (ossification of the posterior longitudinal ligament) in patients with cervical OPLL. MethodsWe retrospectively analyzed the clinical data of cervical OPLL patients in Changzheng hospital, who received chest CT scans for screening of COVID-19, and included 87 patients into this study. According to the radiographic evidence, 87 patients were divided into CT group(cervical OPLL combined with thoracic OPLL）and C group(cervical OPLL group). We measured the cervical OS index (ossification index), and analyzed the relationship between thoracic OPLL and cervical OS index. ResultsThere was no difference of age、sex、duration of symptoms、comorbidity between the 2 groups(P＞0.05). The mean cervical OS index was higher in the CT group than in the C group (8 ± 2 VS 3 ± 2，P＜0.001). ConclusionsPatients with cervical OS index ＞8 was considered as “high risk” of tandem OPLL, while with value ≤ 4 was considered as “low risk”. Index between 5 and 8 were considered as “middle risk”. This study demonstrated that the cervical OS index may be used as an indicator of thoracic OPLL in patients with cervical OPLL, with a high diagnostic accuracy.

Distinct progression pattern of ossification of the posterior longitudinal ligament of the thoracic spine versus the cervical spine: a longitudinal whole-spine CT study.

Data regarding risk factors for the progression of ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine are scarce. Therefore, in this study, the authors aimed to elucidate the difference in the radiographic progression pattern of OPLL and its risk factors between cervical and thoracic OPLL using longitudinally acquired whole-spine CT scans. Overall, 123 patients with symptomatic OPLL who underwent repeated whole-spine CT examinations, with an average interval of 49 months (at least 3 years) between scans, were retrospectively reviewed. Progression of OPLL was assessed to compare the distribution of OPLL over the entire spine on the initial and final CT scans. Patients were divided into a cervical OPLL (C-OPLL) group and a thoracic OPLL (T-OPLL) group according to the location of the main lesion. The progression pattern of OPLL and its risk factors were compared between the two groups using the Student t-test or Mann-Whitney U-test. In the C-OPLL group, 15 (22.1%) of 68 patients had OPLL progression, of whom 12 patients (80.0%) had progression only in the cervical spine and 3 patients (20.0%) had progression in multiple regions (cervical and thoracic/lumbar). In the T-OPLL group, 16 (29.1%) of 55 patients had OPLL progression, of which 3 patients (18.8%) had progression only in the thoracic spine and 8 patients (50.0%) had progression in multiple regions. Young age was a common risk factor for OPLL progression regardless of the location of OPLL, and this trend was more pronounced in the T-OPLL group than in the C-OPLL group. High BMI, male sex, and multilevel, severe T-OPLL were identified as independent risk factors for progression of T-OPLL (OR 1.19, 95% CI 1.03-1.37; OR 10.5, 95% CI 1.39-81.94; and OR 1.24, 95% CI 1.16-1.45, respectively). Patients with T-OPLL are predisposed to diffuse progression of OPLL over the entire spine, whereas patients with C-OPLL are likely to have progression in only the cervical spine. Young age and high BMI are significant risk factors for OPLL progression, especially in patients with T-OPLL. Our study highlights the need for continued follow-up in patients with T-OPLL, especially in young patients and those with obesity, for early detection of spinal cord and cauda equina symptoms due to the progression of OPLL throughout the spine.

Perioperative Complications of Anterior Decompression with Fusion in Degenerative Cervical Myelopathy-A Comparative Study between Ossification of Posterior Longitudinal Ligament and Cervical Spondylotic Myelopathy Using a Nationwide Inpatient Database.

For ossification of the posterior longitudinal ligament (OPLL) and cervical spondylotic myelopathy (CSM), anterior decompression with fusion (ADF) can accurately achieve spinal decompression. However, the difference in perioperative complications in ADF between OPLL and CSM is poorly described. This study aimed to investigate the perioperative complication rates of patients with degenerative cervical myelopathy undergoing ADF, represented by OPLL and CSM, using a large national inpatient database. In the OPLL and CSM groups, postoperative complication (systemic and local) rates, reoperation rates, medical costs during hospitalization, and mortality after propensity score matching were compared. After matching, 1197 matched pairs were made. The incidence of total systemic complications was similar between both groups (OPLL, 12.4%; CSM, 12.2%). In the OPLL group, more perioperative local complications (cerebrospinal fluid leakage: CSFL, [OPLL, 2.7%; CSM, 0.3%] and surgical site infection: SSI [OPLL, 2.1%; CSM, 0.9%]) were detected, and the hospitalization cost was approximately $3200 higher than that in the CSM group. Moreover, medical costs were significantly higher in patients who experienced complications in both OPLL and CSM. The frequency of perioperative complications of OPLL and CSM in ADF was detailed using large real-world data. Compared to CSM, OPLL had more perioperative complications such as CSFL and SSI, and higher medical costs. Regardless of the disease, medical costs were significantly increased when perioperative complications occurred.

Evaluation of bone strength using finite-element analysis in patients with ossification of the posterior longitudinal ligament

BACKGROUND CONTEXTPatients with ossification of the posterior longitudinal ligament (OPLL) are often reported to have increased bone mineral density (BMD). The bone strength of the proximal femur measured by quantitative computed tomography-based finite element analysis (QCT/FEA) is reportedly comparable between healthy subjects with and without OPLL. However, the bone strength in symptomatic OPLL patients remains unknown. PURPOSETo investigate bone strength measured by QCT/FEA in symptomatic patients with OPLL. STUDY DESIGN/SETTINGA single-center prospective observational study. PATIENT SAMPLEA total of 157 patients with cervical or thoracic compressive myelopathy were included in the study. OUTCOME MEASURESWe analyzed patients’ characteristics, Japanese Orthopedic Association (JOA) score, serum laboratory tests including calcium (Ca), inorganic phosphate (Pi), and bone turnover markers, BMD of the proximal femur and lumbar spine measured using dual-energy X-ray absorptiometry, and predicted bone strength (PBS) of the proximal femur and lumbar spine measured using QCT/FEA. METHODSEligible patients were divided into the non-OPLL and OPLL groups. We compared the patients’ characteristics, JOA scores, laboratory data, BMD, and PBS of the proximal femur and lumbar spine between the non-OPLL and OPLL groups among total, male, and female patients by performing Fisher's exact test for categorical variables and the unpaired t test for continuous variables. Then, we used the inverse probability weighted logistic regression model after calculating propensity scores to compare the bone metabolism-associated markers, BMD, and PBS measurements between the groups. RESULTSAmong the eligible 157 patients, 68 were in the non-OPLL group and 89 were in the OPLL group. Compared with the non-OPLL group, the OPLL group had a significantly younger age and higher BMI in the total, male, and female patients. The JOA scores in the total and female patients were significantly higher in the OPLL group than in the non-OPLL group. The OPLL group showed significantly lower Ca levels in the female patients and significantly lower Pi levels in the total or male patients compared with the non-OPLL group in the inverse probability weighting method. The BMD of the proximal femur and lumbar spine and the PBS of the proximal femur were significantly higher in the OPLL group than in the non-OPLL group. There were no significant differences in the PBS and BMD between the male subgroups. However, the BMD and PBS of the proximal femur and lumbar spine were significantly higher in the OPLL females than in the non-OPLL females. CONCLUSIONSHyperostosis of the posterior longitudinal ligament in OPLL was associated with higher bone strength by QCT/FEA, especially in female OPLL patients.

Serum Periostin Level Reflects Progression of Ossification of the Posterior Longitudinal Ligament.

Background:Ossification of the posterior longitudinal ligament (OPLL), characterized by ectopic new bone formation in the spinal ligament, causes neurological impairment due to narrowing of the spinal canal. However, the etiology has not been fully elucidated yet. Several biomarkers may be related to the pathogenesis of OPLL. The present study focused on the serum level of periostin, which is recognized as an important bone formation regulator.Methods:This study included 92 patients with OPLL and 54 control patients without OPLL. For the case-control analysis, 54 age and sex-matched patients were randomly included in the OPLL group. The serum fibroblast growth factor-23 (FGF-23), creatinine, inorganic phosphate, calcium, alkaline phosphatase, and periostin levels were assessed. Furthermore, the calcium, creatinine, and inorganic phosphate levels in urine and the percentage of tubular reabsorption of phosphate were also analyzed. Moreover, the relationship between the biomarkers and the extent of OPLL was analyzed. The data were compared between patients with OPLL progression (the progression group) and without OPLL progression (the non-progression group).Results:The mean serum FGF-23 and periostin levels in the OPLL group were higher than that in the control group. The serum inorganic phosphate level in the OPLL group was lower than that in the control group. No correlation was found between any of the biomarkers and the extent of ossification. The serum periostin level in the progression group was higher than that in the non-progression group. No significant difference in the serum FGF-23 level was noted between the progression and non-progression groups. Moreover, no correlation was found between serum periostin and FGF-23 levels.Conclusions:The serum periostin level is related to OPLL progression.Level of Evidence:Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Aggravation of Ossified Ligamentum Flavum Lesion Is Associated With the Degree of Obesity.

Retrospective cross-sectional study. 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. 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. 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. 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.

Unveiling the genetic variation of severe continuous/mixed-type ossification of the posterior longitudinal ligament by whole-exome sequencing and bioinformatic analysis

Ossification of the posterior longitudinal ligament (OPLL) in the cervical spine is known as a rare, complex genetic disease, its complexity being partly because OPLL is diagnosed by radiological findings regardless of clinical or genetic evaluations. Although many genes associated with susceptibility have been reported, the exact causative genes are still unknown. We performed an analysis using next-generation sequencing and including only patients with a clear involved phenotype. This was a case control study. A total of 74 patients with severe OPLL and 26 healthy controls were included. Causal single-nucleotide variant (SNV), gene-wise variant burden (GVB), and related pathway METHOD: We consecutively included the severe OPLL patients with continuous-/mixed-type and an occupying ratio of ≥ 40%, and performed whole-exome sequencing (WES) and bioinformatic analysis. Then, a validation test was performed for candidate variations. Participants were divided into 4 groups (rapidly-growing OPLL, growing rate ≥ 2.5%/y; slow-growing, < 2.5%/y; uncertain; and control). WES was performed on samples from 74 patients with OPLL (rapidly-growing, 33 patients; slow-growing, 37; and uncertain, 4) with 26 healthy controls. Analysis of 100 participants identified a newly implicated SNV and 4candidate genes based on GVB. The GVB of CYP4B1 showed a more deleterious score in the OPLL than the control group. Comparison between the rapidly growing OPLL and control groups revealed seven newly identified SNVs. We found significant association for 2 rare missense variants; rs121502220 (odds ratio [OR]=infinite; minor allele frequency [MAF]=0.034) in NLRP1 and rs13980628 (OR= infinite; MAF=0.032) in SSH2. The 3 genes are associated with inflammation control and arthritis, and SSH2 and NLRP1 are also related to vitamin D modulation. Identification of unique variants in novel genes such as CYP4B1 gene may induce the development of OPLL. In subgroup analysis, NLRP1 and SSH2 genes coding inflammation molecules may related with rapidly-growing OPLL.