Hyperlipidemia, Obesity, and Diabetes, and Risk of Ossification of the Posterior Longitudinal Ligament.

BACKGROUND: Several risk factors of ossification of the posterior longitudinal ligament (OPLL) have been established, including diabetes and obesity. However, the relationship between hyperlipidemia (HLD) and OPLL is incompletely understood. METHODS: PearlDiver was queried to identify adults with (+) and without (-) HLD, diabetes, and obesity. Comparative analyses were performed on demographics, comorbidities, and OPLL rates before and after matching for age, sex, and comorbidities. Stepwise logistic regression modeling assessing the relationship between HLD and OPLL with the addition of predictor variables was also performed. RESULTS: In total, 31,677 cervical OPLL patients, as well as 170,467 HLD+ and 118,665 HLD-, 168,985 Diabetes+ and 137,966 Diabetes-, and 150,363 Obesity+ and 142,553 Obesity- patients, were examined. Mean age ranged 43.44-59.46 years, 54.94-63.12% were females, and mean Charlson Comorbidity Index ranged from 0.06 from 1.53, all higher in those with the comorbidity. Before matching, OPLL rates were higher in those with HLD (HLD+=0.05% vs. HLD-=0.03%, P = 0.005), diabetes (Diabetes+=0.06% vs. Diabetes-=0.02%, P < 0.001), and obesity (Obesity+=0.05% vs. Obesity-=0.02%, P = 0.001). However, after matching by age, sex, and Charlson Comorbidity Index, the associations between the studied comorbidities and OPLL were attenuated (all P > 0.05). Stepwise regression modeling revealed an association between HLD and cervical OPLL that was most impacted by the addition of age (OR=1.95, R2 = 0.029 to OR=1.38, R2 = 0.075) and obesity (OR=1.21, R2 = 0.086 to OR=1.07, R2 = 0.111) into the model. CONCLUSIONS: Cervical OPLL rates were higher in patients with HLD even after accounting for demographics and comorbidities. HLD may be an independent risk factor for OPLL development.

Patients with a large ossification of the posterior longitudinal ligament have a higher incidence of arteriosclerosis in the carotid artery.

PURPOSE: This study aimed to investigate the impact of the severity of cervical ossification of the posterior longitudinal ligament (OPLL) on the incidence of arteriosclerosis in the carotid artery. METHODS: Patients with OPLL-induced cervical myelopathy were prospectively enrolled. The study involved analyzing patient characteristics, blood samples, computed tomography scans of the spine, and intima-media thickness (IMT) measurements of the common carotid artery. Patients were divided into two groups based on the size of the cervical OPLL to compare demographic data, comorbidities, and the presence of thickening of the carotid intima-media (max IMT ≥ 1.1 mm). RESULTS: The study included 96 patients (mean age: 63.5 years; mean body mass index: 26.9 kg/m2; 71.8% male; 35.4% with diabetes mellitus). The mean maximum anteroposterior (AP) diameter of the OPLL was 4.9 mm, with a mean occupancy ratio of 43%. The mean maximum IMT was 1.23 mm. Arteriosclerosis of the carotid artery was diagnosed in 62.5% of the patients. On comparing the two groups based on OPLL size, the group with larger OPLL (≥ 5 mm) had a higher BMI and a greater prevalence of carotid intima-media thickening. This significant difference in the prevalence of carotid intima-media thickening persisted even after adjusting for patient backgrounds using propensity score matching. CONCLUSIONS: Patients with a larger cervical OPLL showed a higher frequency of intima-media thickening in the carotid artery.

Plasma pentosidine concentration is associated with ligament ossification and high-grade osteoarthritis: The ROAD study.

AIM: No studies have examined the association between plasma pentosidine levels and ossification diseases in large cohorts of Japanese residents. This study aimed to investigate the association between cervical ossification of the posterior longitudinal ligament (OPLL) and other ossification diseases, including diffuse idiopathic skeletal hyperostosis, lumbar spondylosis and knee osteoarthritis (OA), by examining plain radiographs of the knee, and cervical, thoracic and lumbar spine from 1690 participants, and the association between these diseases and plasma pentosidine. DESIGN: We enrolled 1690 participants (596 men and 1094 women) from mountainous and coastal areas from the study population of the previous Research on Osteoarthritis/Osteoporosis Against Disability study. X-ray examination of the cervical/thoracic/lumbar spine and knee was carried out only in these individuals, and not those from urban areas. Plasma pentosidine concentrations were determined using enzyme-linked immunoassays. RESULTS: Radiographic OPLL was detected in 30 (17 men, 13 women) of 1562 individuals who underwent X-ray examination of the cervical spine. OPLL, diffuse idiopathic skeletal hyperostosis, lumbar spondylosis Kellgren-Lawrence (KL) grade, and knee OA KL grade were associated with high plasma pentosidine concentrations (all P < 0.05). Furthermore, significant intragroup differences (KL grade 4 vs 3) of plasma pentosidine concentration were observed between the lumbar spondylosis and knee OA groups. The plasma pentosidine concentration was significantly associated with age, OPLL, lumbar spondylosis (KL grade 4) and knee OA (KL grade 4). CONCLUSIONS: OPLL is significantly associated with other ossification diseases. The development of more severe OA might lead to the accumulation of plasma pentosidine. Plasma pentosidine levels were associated with OPLL and severe OA. Geriatr Gerontol Int 2024; 24: 154-160.

Prevalence and Risk Factors for Modic Changes in Symptomatic Cervical Ossification of the Posterior Longitudinal Ligament: A Retrospective Study of 203 Patients.

BACKGROUND Modic changes (MC) are abnormal bone signals under the vertebral endplates on magnetic resonance imaging (MRI) of the spine. Three types of MC may be seen on MRI as abnormal bone signals of the vertebral endplate and adjacent bone marrow. This retrospective study of 203 patients with symptomatic cervical ossification of the posterior longitudinal ligament (OPLL) aimed to evaluate factors associated with MC on cervical spine MRI. MATERIAL AND METHODS We included 203 patients with symptomatic cervical ossification of the OPLL. All patients underwent MRI with T1 and T2 sequences to assess the presence and type of MC. Univariate and multivariate logistic regression analyses were used to identify the risk factors for MC. RESULTS The prevalence of MC in patients with symptomatic cervical OPLL was 21.18%. Type 2 MC accounted for 88.64% of the cases. Local type and MC share the same segment (100.00%), followed by segmental type (77.27%), mixed type (75.00%), and continuous type (75.00%). Age (OR=1.05, 95% CI: 1.01-1.09, P=0.013) and neck pain (OR=2.67, 95% CI: 1.04-6.83, P=0.041) were significantly correlated with MC. Further receiver operating characteristic (ROC) analysis displayed an area under the curve (AUC) of 0.657 (P=0.002) for age, and the optimal cutoff was 60.50 years (sensitivity 0.67, specificity 0.68). CONCLUSIONS The results of this study found that older age and neck pain were significantly associated with development of cervical spine MC. Patients ≥60.5 years with symptomatic cervical OPLL had a higher probability of developing MC.

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

BACKGROUND CONTEXT: Obesity 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. PURPOSE: We aimed to determine the association between dyslipidemia and symptomatic OPLL. STUDY DESIGN: Single institution cross-sectional study. PATIENT SAMPLE: Data 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 MEASURES: Baseline 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. METHODS: Patient 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. RESULTS: The 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. CONCLUSIONS: We 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.

Characteristics of the cervical spine and cervical cord injuries in older adults with cervical ossification of the posterior longitudinal ligament.

Although the incidence of cervical spinal cord injury (CSCI) with ossification of the posterior longitudinal ligament (OPLL) has increased in older adults, its etiology and neurological outcomes remain unknown. We identified OPLL characteristics and determined whether they influence neurological severity and improvement of CSCI in older patients. This multicenter retrospective cohort study identified 1512 patients aged ≥ 65 years diagnosed with CSCI on admission during 2010-2020. We analyzed CSCI etiology in OPLL patients. We performed propensity score-adjusted analyses to compare neurological outcomes between patients with and without OPLL. Cases were matched based on variables influencing neurological prognosis. The primary neurological outcome was rated according to the American Spine Injury Association (ASIA) impairment scale (AIS) and ASIA motor score (AMS). In 332 OPLL patients, the male-to-female ratio was approximately 4:1. Half of all patients displayed low-energy trauma-induced injury and one-third had CSCI without a bony injury. Propensity score matching created 279 pairs. There was no significant difference in the AIS grade and AMS between patients with and without OPLL during hospitalization, 6 months, and 12 months following injury. OPLL patients tended to exhibit worse neurological findings during injury; nevertheless, OPLL was not associated with poor neurological improvement in older CSCI patients.

Significance of body mass index on thoracic ossification of the ligamentum flavum in Chinese population.

PURPOSE: To investigate the risk factors for thoracic ossification of the ligamentum flavum (TOLF), especially the relationship between BMI and TOLF. METHODS: A total of 856 individuals consisting of 326 controls without ossification of spinal ligaments and 530 TOLF inpatients who underwent thoracic spine decompression surgery at our hospital between January 2013 and September 2020 were included. All subjects were classified into 4 grades: Grade 0) control; Grade 1) single-segment TOLF; Grade 2) multi-segment TOLF; and Grade 3) TOLF combined thoracic ossification of the posterior longitudinal ligament (T-OPLL). Logistic regression analysis was performed to identify the risk factors for TOLF. The TOLF index was calculated to assess the severity of TOLF, and its relationship with BMI was investigated by correlation analysis. RESULTS: Overall, TOLF patients are most numerous in the 50-59 age group. Age and gender were considered as independent risk factors for Grades 1 and 2. BMI was identified as an independent risk factor for TOLF. Furthermore, BMI was significantly higher in Grade 1 (26.1 VS 24.5 kg/m2, P = 0.0001), Grade 2 (28.2 VS 24.5 kg/m2, P < 0.0001), and Grade 3 (29.1 VS 24.5 kg/m2, P < 0.0001) than Grade 0. Notably, in TOLF patients without combined T-OPLL, BMI was positively correlated with TOLF index, while BMI was negatively correlated with age in younger individuals. CONCLUSION: BMI is a crucial risk factor for TOLF. It highlights the necessity of close follow-up of asymptomatic TOLF patients with high BMI to detect and treat their TOLF progression promptly.

Cervical Ossification of the Posterior Longitudinal Ligament (OPLL) in Native Hawaiians and/or Polynesians: A 3-year Retrospective Demographic and Descriptive Pilot Study.

Ossification of the posterior longitudinal ligament (OPLL) is a disease characterized by the replacement of the posterior longitudinal ligament with ectopic bone and cartilage. Historically, the disease was described as highly prevalent in Japanese and other Asian populations. However, recent studies suggest OPLL may have a higher prevalence in non-Asian communities than previously believed. To date, there are no demographic or epidemiologic studies examining OPLL in Native Hawaiian or Polynesian communities. The purpose of this study was to review the demographics and comorbidities of a cohort of patients with OPLL from the author's institution, designated as either Native Hawaiian and/or Polynesian (NHP) or Non-Native Hawaiian and/or Polynesian (NNHP). Demographic findings from this study were similar to previous literature demonstrating higher rates of OPLL in men and older patients with an average age of 56 years in the NHP group and 65 years in the NNHP group. There were no statistically significant differences in the rates of type II diabetes mellitus, coronary vascular disease, chronic kidney disease, or hypertension between NHP and NNHP groups. The NHP group exhibited statistically higher rates of obesity when compared to the NNHP group. Obesity's risk in the development or progression of OPLL in the NHP population has not been examined and requires additional investigation. This study serves as a beginning for further demographic and epidemiologic investigations into OPLL in Native Hawaiian and Polynesian communities to facilitate improved identification of those at risk and guide diagnosis and treatment of these patients.

Association between obesity and ossification of spinal ligaments in 622 asymptomatic subjects: a cross-sectional study.

INTRODUCTION: Previous studies on patients with symptoms of spinal ligament ossification, including ossification of the posterior longitudinal ligament (OPLL) and ligamentum flavum (OLF), have not clarified whether obesity is a cause or consequence of these diseases and were limited by selection bias. Thus, we investigated the association between obesity and the prevalence of spinal ligament ossification in randomly selected asymptomatic subjects. MATERIALS AND METHODS: Between April 2020 and March 2021, 622 asymptomatic Japanese subjects who underwent computed tomography of neck to pelvis for medical check-up purposes were included. All subjects were divided into the following three groups: normal weight (body mass index [BMI] < 25 kg/m2), obese I (25 ≤ BMI < 30 kg/m2), and obese II (BMI ≥ 30 kg/m2). The relationship between factors affecting the presence of each spinal ligament ossification was evaluated using multivariate logistic regression analysis. RESULTS: The proportion of subjects with thoracic OPLL was significantly higher in the obese II group than in the other two groups (vs. normal weight, P < 0.001; vs. obese I, P < 0.001). BMI was associated with the prevalence of OLF, cervical OPLL, thoracic OPLL, and ossification of the anterior longitudinal ligament (OALL). BMI was most significantly associated with the prevalence of thoracic OPLL (ß, 0.28; 95% confidence interval, 0.17-0.39). CONCLUSION: BMI was associated with the prevalence of OALL, cervical OPLL, thoracic OPLL, and OLF in asymptomatic subjects, suggesting that obesity is associated with the development of heterotopic ossification of the spinal ligaments.

High incidence of venous thromboembolism after acute cervical spinal cord injury in patients with ossification of the posterior longitudinal ligament.

Objective: To determine the incidence of venous thromboembolism (VTE) in patients with acute cervical spinal cord injury (SCI) and ossification of the posterior longitudinal ligament (OPLL).Design: Prospective cohort study.Setting: A department of a university hospital in Japan.Participants: This study included 57 patients (OPLL, n = 10; non-OPLL, n = 47) treated for acute cervical SCI between January 2011 and April 2017. Patients were classified according to motor complete paralysis (MC), motor incomplete paralysis (MIC), or normal motor function, based on American Spinal Injury Association (ASIA) Impairment Scale results.Interventions: N/A.Outcome Measures: All patients were screened for VTE by D-dimer monitoring, and some underwent ultrasonography. If ultrasonography indicated deep venous thrombosis (DVT) or if the D-dimers increased to ≥10 µg/mL, patients underwent contrast venography to detect VTE, including DVT or pulmonary embolism. We compared blood coagulability and VTE incidence in the OPLL and non-OPLL groups.Results: VTE occurred in 11 (19.3%) of 57 patients. The incidence of VTE was higher in the OPLL group than in the non-OPLL group (50% vs. 12.8%; P = 0.017) and higher in the MC group (57.1%) than in the MIC (8.3%; P = 0.002) or normal group (5.3%; P = 0.002). In the MC group, VTE occurred in 50% of OPLL patients and in 62.5% of non-OPLL patients (P = 0.529). In the MIC group, VTE occurred in 50% of OPLL patients and in none of the non-OPLL patients (P = 0.022).Conclusions: Patients with OPLL tended to develop VTE after SCI with motor complete and incomplete paralysis.

Ossification of the Posterior Longitudinal Ligament in North American Patients: Does Presentation with Spinal Cord Injury Matter?

OBJECTIVE: We sought to evaluate the influence of trauma-induced spinal cord injury (SCI) on the operative management of cervical ossification of the posterior longitudinal ligament (OPLL) in a North American cohort. METHODS: A retrospective chart review was performed for all patients who underwent surgical management for OPLL in an academic medical center between November 2006 and July 2019. Patients were categorized into 1 of 2 groups and compared on the basis of their initial presentation: 1) SCI with OPLL or 2) cervical myelopathy (CM) with OPLL. Patient characteristics were collected. OPLL classification and K-line measurements were performed. Surgical approach, levels fused/decompressed, blood loss, postoperative length of stay, surgical complications, and neurologic outcome were recorded. RESULTS: Among the 28-patient cohort, 12 were in the SCI with OPLL group and 16 were in the CM with OPLL group. The most common type of OPLL in both groups was segmental (n = 21, 75%). The average levels fused/decompressed (P = 0.0176), estimated blood loss (P = 0.0204), and postoperative length of stay (P = 0.0003) were all significantly higher in the SCI with OPLL group. There were significantly more anterior-only surgical approaches performed in the CM with OPLL group (P = 0.0159). The motor score at admission (P = 0.0005) and at latest follow-up (P = 0.0003) for the SCI with OPLL group was significantly lower than the CM with OPLL group. CONCLUSIONS: Patients with SCI complicated by OPLL had worse preoperative and postoperative neurologic motor scores as compared with patients in the CM with OPLL group. Most of the patients in our cohort showed neurologic improvement.

Ossification of the Posterior Longitudinal Ligament in Cervical Spine Cases Trends in Surgical Treatments and Outcomes in the US from 2005 to 2013.

BACKGROUND: Ossification of the posterior longitudinal ligament (OPLL) is characterized by ectopic bone formation within the ligament and can elicit cervical spinal canal stenosis. Surgical treatment for OPLL is debated in the literature. This study examined nationwide data to estimate the prevalence of cervical OPLL (C-OPLL) and investigated trends in surgical treatment and outcomes. METHODS: A retrospective cross-sectional study was conducted of the National Inpatient Sample (NIS) database for patients with a diagnosis code for C-OPLL (ICD-9-CM 723.7) from 2005 to 2013. NIS supplied hospital- and yearadjusted weights allowed for accurate assessment of prevalence. Descriptive statistics assessed patient demographics, comorbidities, surgical factors, and complications. Trends were analyzed using chi-squared, ANOVA, and independent sample t-tests. RESULTS: A total of 4,601 C-OPLL discharges were identified (56.7 years, 43% female). The prevalence of C-OPLL has increased from 0.7/100,000 in 2005 to 2.1/100,000 in 2013. Among hospitalized C-OPLL patients, 89.1% underwent surgery, with 62.1% undergoing an anterior-only (A) approach, 21.5% posterior-only (P), and 16.4% combined (AP). Rates of anterior- and decompression-only surgeries have declined since 2005, from 67.5% to 44.4% and 21.6% to 14.8%, respectively (p < 0.001 for both). Corpectomy rates have dramatically increased, from 3.6% to 27.2% (p < 0.001). Overall complication rates have increased 2.5% since 2005 (p < 0.001) with higher rates of dysphagia (0.7%) and dural tears (5.6%) associated with A-only surgeries (p < 0.001 for both). The overall mortality rate was 0.8%, with P surgery associated with the highest rate, 1.6% (p = 0.002). CONCLUSIONS: The rate of hospitalization for C-OPLL has increased over the last decade as have morbidity rates for C-OPLL discharges. Anterior-only surgeries were associated with higher complication rates. Surgical rates have remained constantsince 2005, butrates of anterior-only and decompression-only procedures have decreased in favor of posterior-only and combined-approach surgeries.

Prevalence of Ossification of Posterior Longitudinal Ligament in Patients With Degenerative Cervical Myelopathy: Cervical Spine 3D CT Observations in 7210 Cases.

STUDY DESIGN: A cross-sectional study. OBJECTIVE: The aim of this study was to investigate the prevalence of ossification of posterior longitudinal ligament (OPLL) in patients with degenerative cervical myelopathy (DCM). SUMMARY OF BACKGROUND DATA: OPLL of the cervical spine is one of the main entities of DCM in Asian populations. However, few studies have reported the prevalence of cervical OPLL in DCM patients. METHODS: A total of 7210 DCM patients (4546 males and 2664 females; mean age: 54 years) who underwent cervical spine three-dimensional computed tomography (3D-CT) at the Shanghai Changzheng Hospital between January 2012 and December 2016 were included in this study. Demographic data including age, sex, height, body weight, body mass index (BMI), concomitant diabetes mellitus (DM), and hypertension were recorded. The imaging diagnosis criterion for OPLL was thickness >2 mm on axial imaging. RESULTS: The overall prevalence of OPLL in the 7210 DCM patients was 18.22%, including 19.73% in males and 15.65% in females, with a significant difference between the two groups (P < 0.001). The prevalence of OPLL in DM and hypertensive patients was significantly higher than that in non-DM and normotensive patients (24.16% vs. 18.76% and 22.26% vs. 17.91%, both P < 0.001). Comparison by age and BMI showed that the prevalence of OPLL was the highest in the 70- to 79-year age group (21.91%) and obesity group (26.51%), respectively. CONCLUSION: This CT-based study revealed that the overall prevalence of OPLL in DCM patients was 18.22%. Furthermore, old age, male sex, comorbid hypertension or DM, and high BMI were risk factors for cervical OPLL. Given its high prevalence, CT examination is suggested to identify possible OPLL in DCM patients. LEVEL OF EVIDENCE: 2.

Association between ossification of the posterior longitudinal ligament and ossification of the nuchal ligament in the cervical spine.

OBJECTIVES: To investigate the association between ossification of the posterior longitudinal ligament (OPLL) and ossification of the nuchal ligament (ONL) in terms of incidence and size. METHODS: This retrospective study evaluated 297 patients who underwent CT of the cervical spine (C-spine). Two radiologists worked in consensus. The incidence of OPLL from patients with and without ONL was compared using Chi Square tests. The mean lengths of ONL from patients with and without OPLL were compared using Student t-test. The correlations between the length of ONL and the presence of OPLL and between the length of ONL and the length of OPLL were analyzed with Pearson correlations. RESULTS: We found that OPLL occurred more frequently in patients with ONL than in patients without ONL (odd ratio = 2.524, p = 0.037); however, the mean length of ONL did not differ significantly patients with and without OPLL (p = 0.874). We found no significant correlation between the length of ONL and the length of OPLL (p = 0.233). CONCLUSION: The presence of ONL was associated with the presence of OPLL. The length of OPLL and ONL showed no correlation.

Epidemiology of ossification of the spinal ligaments and associated factors in the Chinese population: a cross-sectional study of 2000 consecutive individuals.

BACKGROUND: The epidemiology and cause of ossification of the spinal ligaments (OSL) remains obscure. To date, there is no study that comprehensively evaluates the prevalence, distribution, and concomitance of each type of OSL by CT among general Chinese population. We therefore aimed to comprehensively investigate epidemiological characteristics of OSL using whole spine CT in the Chinese population and examine the factors that correlate with the presence of OSL. METHODS: Ossification of the posterior longitudinal ligament (OPLL), ligamentum flavum (OLF), anterior longitudinal ligament (OALL), nuchal ligament (ONL), and diffuse idiopathic skeletal hyperostosis (DISH) were evaluated from the subjects who underwent PET/CT for the purpose of cancer screening in our hospital. Prevalence, distribution, and concomitance of OSL were reviewed. Logistic regression analysis was performed to identify the risk factors of OSL. RESULTS: A total of 2000 subjects (1335 men and 665 women) were included. The prevalence rate of cervical OPLL (C-OPLL) was 4.1%, thoracic OPLL (T-OPLL) 2.25%, lumbar OPLL (L-OPLL) 0.8%, thoracic OLF (T-OLF) 37.65%, lumbar OLF (L-OLF) 1.45%, ONL 31.5%, DISH 3.85%. The most commonly involved level was C5 for C-OPLL, T1 for T-OPLL, T10 for T-OLF, and T8/9 for OALL. 21% of subjects with C-OPLL had T-OPLL, 44% of C-OPLL had T-OLF, 38% of T-OPLL had C-OPLL, 53% of T-OPLL had T-OLF, 44% of L-OPLL had T-OPLL, and 56% of L-OPLL had T-OLF. The average age of OSL-positive subjects was significantly higher than that of OSL-negative subjects. The results of the multiple regression analysis revealed that males had a strong association with DISH (odds ratio, 3.15; 95% confidence interval, 1.27-7.78; P = 0.013). CONCLUSION: The prevalence of OSL in the Chinese was revealed. Tandem ossification is not uncommon in people with OSL. There is a high incidence of multiple-regional OPLL in the whole spine. Approximately half of the subjects with OPLL coexist with T-OLF. For patients with clinical symptoms induced by OPLL, thorough evaluation of whole spine using CT is recommended.

Radiological Characteristics and Surgical Outcome of Patients with Long Ossification of the Posterior Longitudinal Ligament Resulting in Ossified Lesions in the Upper Cervical Spine.

OBJECTIVE: Designing surgical strategies for ossified lesions in the upper cervical spine is challenging owing to the complex anatomic structures. The present study aimed to clarify the prevalence of ossified lesions in the upper cervical spine in patients with ossification in the posterior longitudinal ligament and illustrate the clinical features, radiological findings, and surgical outcomes of this abnormality. METHODS: Demographic and clinical data were collected for all patients preoperatively and included age, gender, body mass index, alcohol and tobacco use, history of diabetes, visual analog score, and Japanese Orthopaedic Association score. The cervical angle, morphology of ossification in the posterior longitudinal ligament, K-line, occupation ratio, space available for the spinal cord, high-intensity zone, and compression ratio of the spinal cord were calculated. The operative approach, technique used, and complications were recorded. RESULTS: A total of 38 patients were enrolled. The upper cervical segment in 23 patients was not surgically addressed. In the group with the upper cervical segment addressed surgically, 10 patients were treated with C3-C6 open-door laminoplasty and C2 partial laminectomy, 1 with C1-C7 laminoplasty, 1 with C2-C7 laminoplasty, 2 with C3-C6 total and C2 partial laminectomy, and 1 with C1-C5 laminectomy and occipitocervical fusion. CONCLUSIONS: The development of ossified lesions in the upper cervical spine has a high incidence. Decompressive surgery for upper cervical spine segments should be recommended for patients with severe narrowing of the spinal canal and a high signal intensity that extends to the upper cervical segment of the spinal cord. We hope that the findings from the present study will aid in clinical decision-making and provide useful information that can be incorporated into future guidelines.

Quantification of Risk Factors for Cervical Ossification of the Posterior Longitudinal Ligament in Korean Populations: A Nationwide Population-based Case-control Study.

STUDY DESIGN: Case-control study. OBJECTIVE: To quantify risk factors for cervical ossification of the posterior longitudinal ligament (OPLL) using a large nationwide cohort in Korea, a country with a high prevalence of OPLL. SUMMARY OF BACKGROUND DATA: OPLL is a pathological calcification of the posterior longitudinal ligament of the spine. OPLL progression can cause spinal cord injury that results in disability. Considering neurologic deficits and disability caused by OPLL, identifying OPLL risk factors for early prediction have important health benefits. METHODS: The nationwide population-based matched cohort study was conducted using the Korean National Health Insurance Service cohort data. We selected patients with a primary diagnosis of OPLL involving cervical lesion (International Classification of Diseases-10 code: M48.82, M48.83). A matched cohort without cervical OPLL was enrolled by randomly matching patients by sex, age, year of diagnosis, and residential area to the OPLL group with a ratio of 1:9. Logistic regression analyses were performed to identify risk associated with OPLL development using odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Comorbidities, such as hypertension (OR = 1.283, 95% CI 1.071-1.538), ischemic stroke (OR = 1.386, 95% CI 1.017-1.889), diabetes mellitus (OR = 1.331, 95% CI 1.098-1.615), hypothyroidism (OR = 1.562, 95% CI 1.165-2.094), and osteoporosis (OR = 1.456, 95% CI 1.151-1.842), were significantly associated with the prospective development of OPLL, with low predictive value. CONCLUSION: OPLL was significantly associated with comorbidities such as hypertension, ischemic stroke diabetes mellitus, hypothyroidism, and osteoporosis. Our findings can provide helpful information for OPLL prediction and offer important health benefits. LEVEL OF EVIDENCE: 3.

Obesity and calcification of the ligaments of the spine: a comprehensive CT analysis of the entire spine in a random trauma population.

BACKGROUND CONTEXT: Obesity, which is currently surging to epidemic levels within the United States, has been linked to hyperostotic conditions like diffuse idiopathic skeletal hyperostosis (DISH) and ossification of the posterior longitudinal ligament (OPLL). Excess adipose tissue and insulin-resistance may cause a systemic increase in serum levels of proinflammatory cytokines and these signals can affect bone metabolism. Spinal ligaments and discs may have receptors for these signaling molecules. Anecdotal observations at this institution suggested that there is a clinically important subset of younger patients with obesity and multilevel stenosis in the presence of unusual calcification of the spinal ligaments that is distinct from DISH. PURPOSE: To determine if there is an association between truncal obesity and calcifications of the spine in nonelderly adults. STUDY DESIGN/SETTING: This is a retrospective analysis of 214 sequential trauma patients between the ages of 29 and 50. Patients' age, sex, truncal obesity, history of hypertension, and diabetes were assessed for association with ligamentous calcification of the spine. PATIENT SAMPLE: Sequential trauma patients were chosen from our institution's trauma database between 2006 and 2007. METHODS: Full spine computed tomography (CT) imaging was examined for bone formation in the region of the anterior longitudinal ligament (ALL) and annulus, posterior longitudinal ligament (PLL) and annulus, and the ligamentum flavum (LF). Visceral and subcutaneous abdominal fat were also evaluated. The authors report no study funding sources or conflicts of interest. OUTCOME MEASURES: Calcification of the ALL, PLL, and LF were assigned a score at each level and then combined for a total calcification score (TCS) for the entire spine. Obesity was estimated using a truncal body mass index (TBMI) by using a previously validated CT derived truncal total adiposity volume (TAV). RESULTS: ALL calcification was associated with age, male gender, hypertension, and increased adiposity. PLL calcification was significantly associated with age and hypertension. LF calcification was only associated with increased obesity. CONCLUSIONS: In our analysis of nonelderly patients, LF calcification was independently associated with truncal obesity. This implies obesity plays a greater role in calcification than could be accounted for by simply age-related degeneration or gender.

Radiological Characteristics and Clinical Outcome of Ossification of Posterior Longitudinal Ligament Involving C2 After Posterior Laminoplasty and Instrumented Fusion Surgery.

STUDY DESIGN: Retrospective study. OBJECTIVE: To analyze the radiological characteristics and surgical outcome of cervical ossification of posterior longitudinal ligament (OPLL) involving C2 level. SUMMARY OF BACKGROUND DATA: The study and report focused on the OPLL involving C2 level are rare. Therefore, the radiological characteristics and surgical outcome remain unclear. METHODS: The records of the patients with OPLL involving C2 level who underwent posterior surgery from July 2006 through October 2015 were retrospectively reviewed. The types, longitudinal and transverse extent, occupation ratio, K-line classification of OPLL, and high-intensity zone of spine cord on magnetic resonance imaging were analyzed to evaluate the radiological characteristics. All the cases received posterior open-door laminoplasty and instrumented fusion surgery. The Japanese Orthopedic Association (JOA) score and recovery rate (RR) were used to evaluate neurological function after surgery. RESULTS: A total of 45 patients with OPLL involving C2 level were enrolled in the study. Their radiological data were carefully analyzed. The mixed (73.3%) and continuous type (24.5%) were observed. The mean number of involved segments was 5.1. The narrowest spinal canal mostly located in the level of C3-C4 and mean occupying ratio was 65.3%. Thirty-two patients were followed up for at least 2 years and the mean follow-up time was 46.2 months. The mean JOA score was 10.3 preoperatively and 15.2 at the final follow-up and the mean RR was 70.7%. The K-line (+) and (-) subgroups showed similar preoperative JOA score and RR. The high-intensity zone (+) subgroup showed lower preoperative JOA score but equal RR with (-) subgroup. CONCLUSION: When OPLL involve C2 level, it often presented different radiological characteristics. The posterior open-door laminoplasty and instrumented fusion surgery could achieve favorable clinical outcomes. Further researches and long-term clinical follow-up are needed to better appreciate the OPLL involving C2 level. LEVEL OF EVIDENCE: 4.

Ossification of posterior longitudinal ligament and fluorosis.

OBJECTIVE: Ossification of posterior longitudinal ligament (OPLL) is a progressive disease that causes spinal canal compromise and serious neurological sequelae in advanced cases. The incidence of OPLL in the Asiatic population is 2%-3%, but the incidence is more in the background of fluorosis. Our aim was to study the association of OPLL with fluorosis by comparing urine fluoride levels and to study the types of OPLL. MATERIALS AND METHODS: Thirty consecutive patients with OPLL, observed on cervical skiagram, and confirmed by the computed tomography (CT) of the cervical spine, underwent a 24-h urine fluoride level assessment by the ion-selective electrode method. Due consent of all the patients was obtained and the data was collected. Thirty patients with a normal cervical radiograph were taken as a control group and their 24-h urine fluoride levels were compared with the test group. The 24-h urine fluoride level above 1.6 mg/L was taken as the diagnostic parameter of fluorosis. Imaging analysis of the study group focused on the subtype of OPLL, the mass occupying ratio, the sagittal cervical angle, the signs of dural penetration, and the spinal levels involved. Urinary fluoride levels were correlated with the presence of OPLL and different types of OPLL. RESULTS: Of the 30 patients with OPLL, 25 were males and 5 were females. The most common presentation was myelopathy. Continuous type of OPLL was seen in 11 (36.6%), segmental in 8 (26.6%), focal in 5 (16.6%), and mixed variant in 6 (20%) patients. 24-h urinary fluoride levels ranged from 0.26 mg/L to 12.2 mg/L. 18 (60%) of the patients in the study group were found to have urinary fluoride levels above 1.6 mg/L and only 1 patient (4%) of the control group had the urine fluoride level >1.6 mg/L. This difference was statistically significant. Patients with continuous and mixed types of OPLL had a higher mean urine fluoride level than those with a segmental and focal type of OPLL. The continuous variant of OPLL had a statistically significant occupancy ratio when compared to the other three variants, and the high mass occupancy ratio of the OPLL was directly associated with the presence of dural penetration. CONCLUSION: Fluorosis is associated with a higher incidence of OPLL. Higher urinary fluoride levels correlate with the severe forms of OPLL.