Progression Of Ossification Of The Posterior Longitudinal Ligament Research Articles

Progression of Cervical Ossification of Posterior Longitudinal Ligament After Laminoplasty or Laminectomy With Posterior Fixation.

Retrospective case analysis. This study was conducted to investigate the course of ossification of the posterior longitudinal ligament (OPLL) progression after laminoplasty (LP) or laminectomy with posterior fixation (PF). LP is now recognized as a standard technique for the treatment of cervical multisegment OPLL; however, PF is beneficial for patients with severe stenosis. In recent years, there has been increasing interest in mechanical stress in OPLL, which is assumed to significantly impact progression. The progression of OPLL was assessed using midline sagittal computed tomography images of the cervical spine at various follow-up points. Radiographic parameters including the C2-C7 Cobb angle, C2-C7 range of motion (ROM), and adjacent cranial and caudal segmental ROMs were measured. Postoperative changes and differences between the LP and PF groups in the radiographic parameters were calculated to assess biomechanical stress. Logistic regression analysis was used to analyze the risk factors affecting the progression rate. The authors included 14 PF and 36 LP patients, with a mean follow-up period of 28.9±20.8 and 37.6±16.8 months, respectively (P=0.069). After surgical treatment, both groups showed loss of cervical lordosis (9.2±6.9 vs. 5.3±8.2 degrees, P=0.220) and C2-C7 ROM (14.6± 13.5 vs. 13.1±12.2 degrees, P=0.861). The decrease of ROM in the cranial adjacent segment was larger in the LP group than in the PF group (0.7±4.1 vs. 1.4±5.5 degrees, P=0.453). The ROM in the caudal adjacent segment decreased in the LP group but increased in the PF group (-1.4±6.2 vs. 2.6±5.1 degrees, P=0.041). The progression rate was 2.15±1.31 mm/mo in the PF group and 1.53±1.04 mm/mo in the LP group (P=0.041). PF showed an odds ratio of 12.917 for a higher progression rate (95% confidence interval, 1.397-119.443; P=0.024). The rate of progression of cervical OPLL was significantly higher after PF than after LP.Level III-a retrospective analysis.

Clinical Impact of Ossification of the Posterior Longitudinal Ligament Progression After Cervical Laminoplasty.

This is a retrospective study. (1) To analyze the incidence of second surgery after initial laminoplasty for ossification of the posterior longitudinal ligament (OPLL) due to disease progression, (2) to examine factors associated with poor surgical outcome. Neurological deterioration after laminoplasty is frequently encountered due to OPLL progression. Of 201 OPLL patients treated by laminoplasty at a single-institution, the 153 monitored for >3 years postsurgery were included in this analysis. Neurological findings were graded by the Japanese Orthopaedic Association (JOA) score. We retrospectively examined the incidence of second surgery due to OPLL progression. We also evaluated the clinical characteristics and the surgical outcomes after second operation to identify potential risk factors for poor outcome. Eight patients required a second surgery due to OPLL progression. Neurological recovery was achieved in 5 of these patients, whereas 3 exhibited continued dysfunction. Patients with poor recovery showed kyphotic changes of spinal alignment and high-intensity regions in the spinal cord on T2-weighted magnetic resonance images (T2-MRI). Only a small fraction of OPLL patients required a second surgery due to OPLL progression. Recovery was poor in those with clear high-intensity T2-MRI signals in the spinal cord.

Progression of Ossification of the Posterior Longitudinal Ligament after Cervical Total Disc Replacement.

ObjectiveTotal disc replacement (TDR) is frequently performed anterior approaching method for the patients diagnosed with cervical disc herniation. This study aimed to assess the degree of ossification of the posterior longitudinal ligament (OPLL) progression after cervical TDR.MethodsTwenty-two male soldiers who underwent cervical TDR surgery from 2009 to 2016 and were followed-up for more than 12 months were enrolled. The enrolled patients were classified as; 1) patients with pre-existing OPLL and without; and 2) patient showing progression of OPLL or not.ResultsTwenty-two men were included in the analysis. The mean follow-up period from the surgery was 41.4 months (range, 12–114 months). The mean age of all patients was 40.7 years (range, 31–52 years). TDR-only was used in 7 cases, and the hybrid surgery (TDR+ACDF) was used in 15 cases. The incidence of progression or newly development of OPLL was significantly higher in pre-existing OPLL group (p=0.01). In 11 cases showing the progression of the OPLL, the mean size of OPLL progression was 4.16 mm (range, 0.34–18.87 mm) in the longitudinal height and 1.57 mm (range, 0.54–3.91 mm) in thickness.ConclusionThe progression of OPLL after cervical TDR was more frequent in patients with pre-existing OPLL than in patients without OPLL. Even though TDR is a major alternative to the treatment of cervical lesions to preserve vertebral segmental motion, careful attention should be paid to whether TDR should be used in patients with OPLL and this should be fully explained to the patient.

The progression of ossification of the posterior longitudinal ligament of the cervical spine: A follow-up study by CT im-aging after laminoplasty

Objective To evaluate the CT imaging after laminoplasty for the patients with ossification of the posterior lon-gitudinal ligament (OPLL) of the cervical spine. Methods From June 2011 to June 2016, Retrospectively analyzed the data of OPLL patients who underwent posterior cervical open-door laminoplasty. There were 21 patients finally enrolled in this study, which consisted of 11 male and 10 female aging from 55-69, mean(61.48±4.29). The preoperative patients all had severe symp-toms of spinal compression. Collected the Japanese Orthopaedic Association Scores(JOA) Scores of all patients for gender, age, pre-operative and postoperative follow-up.The length, width and thickness of OPLL were measured by CT scan and two-dimensional re-construction of cervical spine during preoperative and follow-up, and the average progress rate was calculated. The relationship be-tween OPLL size before surgery and OPLL progress rate after surgery was analyzed. Results A total of 21 patients were included in this study, with an average age of 61.48±4.29 years-old. The mean follow-up time was 3.36±1.92 years. The JOA score of cervi-cal spine was 11.81±1.75 before operationand 14.43±1.69 at the last follow-up time (t=3.8, P<0.01). The progression rate of OPLL length, width and thickness was 3.54± 2.89 mm/year, 0.49± 0.52 mm/year and 0.34± 0.21 mm/year, respectively. Compared with the width and thickness, the average progress speed of the length was statistically significant (t=3.6, P=0.003; t= 3.8, P=0.002). The progression rate of the rostraland caudal of OPLL was 1.54 ±1.19 mm/year and 1.60±1.33 mm/year (t=0.1, P=0.559). Linear regression showed that OPLL length progression speed (mm)=0.05×preoperative length+1.23, R2=0.26 and P=0.02. Theprogres-sion rate of width and thickness of OPLL had no correlation with preoperative OPLL width and thickness. The progression rates of local, segmental, continuous, and mixed OPLL were 3.02±0.26 mm, 2.97±0.65 mm, 3.65±1.14 mm, and 3.82±1.27 mm per year. Conclusion The JOA score of the posterior open-door laminoplasty of the cervical OPLL patients was significantly improved dur-ing a short-term follow up. CT imaging follow-up showed there was progression of OPLL in length, width and thickness, and the progression rate of length was faster than width and thickness. However, there was no significant difference between the progres-sion of rostral and caudal of OPLL. In addition, short-term follow-up showed a positive correlation between the progression rate of OPLL length and the length of OPLL preoperation.The progress rate of mixed and continuous OPLL may be greater than that of seg-mental and limited OPLL. Key words: Cervical vertebrae; Ossification of posterior longitudinal ligament; Tomography, spiral computed; Follow-up studies

Increase of the Serum FGF-23 in Ossification of the Posterior Longitudinal Ligament.

Study Design:Case-control study.Objectives:To determine the possible pathogenesis of ossification of the posterior longitudinal ligament (OPLL) in regard to the serum concentration of fibroblast growth factor 23 (FGF-23).Methods:The study included 95 patients with OPLL and a control group of 73 age- and sex-matched volunteers. The serum concentrations of FGF-23, creatinine (Cre), alkaline phosphatase, calcium (Ca), inorganic phosphate (Pi), and hypersensitive C-reactive protein (hs-CRP) were analyzed from blood samples, and Cre, Ca, Pi, and tubular reabsorption of phosphate were measured using urine samples. We evaluated the severity of ossified spinal lesions in patients with OPLL according to the ossification index (the OP index and the OS index). Data was compared between the OPLL and control group and between the OPLL progression and no progression group.Results:Serum FGF-23 and hs-CRP were higher, and serum Pi was lower in patients with OPLL than in the controls. There was a positive correlation between FGF-23 and hs-CRP and a negative correlation between serum Pi and the OS index; however, the correlations were very weak. Overall, 31.7% of patients had progression of OPLL during follow-up. FGF-23 and hs-CRP were higher in the progression group than in the no progression group.Conclusions:These results might indicate that FGF-23 and hs-CRP are positive markers for OPLL. Phosphate metabolism via FGF-23 might be a target for future study on the pathogenesis of OPLL.

Surgical results and complications of anterior controllable antedisplacement fusion as a revision surgery after initial posterior surgery for cervical myelopathy due to ossification of the posterior longitudinal ligament

Posterior surgery has been widely used as an initial surgery for cervical ossification of the posterior longitudinal ligament (OPLL). However, some patients require revision surgery because of failure of symptom relief or late neurological deterioration after posterior surgery. The aim of this study is to retrospectively investigated the surgical results and complications of anterior controllable antedisplacement fusion (ACAF) as a revision surgical technique after initial posterior surgery for OPLL. The present study concluded 13 patients. The operation duration, blood loss and hospital stay was estimated. Radiologic assessment included type and extent of OPLL, decompression width and antero-posterior (AP) diameter of the spinal cord. The JOA scoring system was used to evaluate the neurological status. Surgery- and implant-related complications such as cerebrospinal fluid (CSF) leakage, spinal cord or nerve injury, subsidence and pseudoarthrosis were all recorded. The results showed that nine patients undergoing revision ACAF because of residual stenosis after initial posterior surgery, two because of OPLL progression, one because of lamina closure, one because of a blind man requiring better neurological function of both hands. The mean decompression width and AP diameter of the spinal cord was 20.3 ± 2.1 mm and 5.8 ± 1.1 mm respectively. The mean postoperative JOA score at last follow-up was significantly better than preoperation (14.8 ± 2.5 vs. 8.5 ± 2.7 points, P < 0.01), with a mean improvement rate of 75.3% ± 12.2%. No complication such as CSF leakage, spinal cord or nerve injury, subsidence and pseudoarthrosis occurred. In conclusion, ACAF is a well choice for revision surgery after initial posterior surgery for OPLL.

A novel revision surgery for treatment of cervical ossification of the posterior longitudinal ligament after initial posterior surgery: preliminary clinical investigation of anterior controllable antidisplacement and fusion

BackgroundCervical ossification of the posterior longitudinal ligament (OPLL) is a progressive disease. Posterior decompression surgery is reported to be an effective and comparatively safe procedure with few complications for treatment of patients with myelopathy caused by OPLL. However, some patients require revision surgery because of late neurological deterioration due to OPLL progression or kyphotic changes in cervical alignment. This study reports preliminary clinical results of anterior controllable antidisplacement and fusion (ACAF), a novel revision surgery after initial posterior surgery for OPLL.MethodsFrom January 2017 to June 2018, ten patients with cervical OPLL who underwent ACAF revision surgery after initial posterior surgery were included in this study. The mean age was 62.1 ± 8.0 years (52–78), and the mean interval between initial posterior surgery and revision was 78.0 ± 48.2 months (5–180). The Japanese Orthopaedic Association (JOA) scales, Neck Disability Index (NDI), visual analog scale (VAS), and surgical complications were recorded.ResultsThe mean surgery time was 179.3 ± 41.8 min (120–240), and the mean blood loss was 432.5 ± 198.3 ml (225–850). The patients were followed up for at least 12 months. The JOA scores improved from 8.7 ± 2.8 to 13.4 ± 2.4; the mean improvement rate was 59.9% ± 16.1%. Postoperative NDI and VAS scores were 13.3 ± 3.7 and 2.0 ± 1.6, respectively, and were significantly improved compared to those before the procedure (P < 0.05). Cervical lordosis improved from 3.8 ± 4.3° to 17 ± 4.6° after revision surgery. There was only one instance of cerebrospinal fluid (CSF) leakage; no instances of postoperative hematoma, C5 root palsy, or hoarseness occurred.ConclusionsThe present study demonstrates that excellent postoperative outcomes can be achieved with the ACAF technique for revision treatment of OPLL. Though further study is required to confirm the conclusion, this novel technique has the potential to serve as an alternative surgical technique for revision treatment of OPLL.

Ubiquitin-dependent proteolysis of CXCL7 leads to posterior longitudinal ligament ossification.

Ossification of the posterior longitudinal ligament (OPLL), a spinal ligament, reduces the range of motion in limbs. No treatment is currently available for OPLL, which is why therapies are urgently needed. OPLL occurs in obesity, is more common in men, and has an onset after 40 years of age. The mechanisms underlying OPLL remain unclear. In this study, we performed a serum proteomic analysis in both OPLL patients and healthy subjects to identify factors potentially involved in the development of OPLL, and found reduced levels of a protein that might underlie the pathology of OPLL. We isolated the protein, determined its amino acid sequence, and identified it as chemokine (C-X-C motif) ligand 7 (CXCL7). Based on these proteomics findings, we generated a CXCL7 knockout mouse model to study the molecular mechanisms underlying OPLL. CXCL7-null mice presented with a phenotype of OPLL, showing motor impairment, heterotopic ossification in the posterior ligament tissue, and osteoporosis in vertebrate tissue. To identify the mechanisms of CXCL7 deficiency in OPLL, we searched for single nucleotide polymorphisms and altered DNA exons, but no abnormalities were found. Although miR-340 levels were found to be high in an miRNA array, they were insufficient to reduce CXCL7 levels. Ubiquitin C-terminal hydrolase1 (UCHL1) was found to be overexpressed in CXCL7-null mice and in the sera of patients with OPLL, and was correlated with OPLL severity. Post-translational modifications of proteins with ubiquitin and ubiquitin-like modifiers, orchestrated by a cascade of specialized ubiquitin activating enzyme (E1), ubiquitin conjugating enzyme (E2), and ubiquitin ligase (E3) enzymes, are thought to control a wide range of cellular processes, and alterations in the ubiquitin–proteasome system have been associated with several degenerative disorders. In addition, the OPLL tissue of CXCL7-null mouse and its primary cells expressed the antibody to ubiquitin (linkage-specific K48). Our data clearly show decreased CXCL7 levels in patients with OPLL, and that OPLL developed in mice lacking CXCL7. Tumor necrosis factor receptor-associated factor (TRAF)6 expression was decreased in CXCL7-null mouse primary cells. Furthermore, K48 polyubiquitination was found in posterior longitudinal ligament ossified tissue and primary cells from CXCL7-null mice. We performed a phosphoproteomics analysis in CXCL7-deficient mice and identified increased phosphorylation of mitogen-activated protein kinase kinase (ME3K)15, ubiquitin protein ligase E3C (UBE3C) and protein kinase C (PKC) alpha, suggesting that ubiquitin-dependent degradation is involved in CXCL7 deficiency. Future studies in the CXCL7-null mouse model are, therefore, warranted to investigate the role of ubiquitination in the onset of OPLL. In conclusion, CXCL7 levels may be useful as a serum marker for the progression of OPLL. This study also suggests that increasing CXCL7 levels in patients can serve as an effective therapeutic strategy for the treatment of OPLL.

Cervical restenosis caused by progressive ossification of the posterior longitudinal ligament in patients following laminoplasty: Two case reports

Abstract We report two cases of restenosis caused by the progression of thickness of ossification of the posterior longitudinal ligament (OPLL) seven and more years after laminoplasty, resulting in neurological deterioration needed for revision anterior decompressive surgeries. Neurological recovery after revision anterior excision of OPLL was poor. In both cases, the patients had progressive OPLL, with a non-ossified segment of the ossification foci, in common. After laminoplasty, they also both exhibited osseous fusion of the elevated laminae, but there was discontinuity at the interlaminar space at the peak level of OPLL. Discontinuity of the osseous fusion in the elevated laminae might cause mechanical stress increases at the non-ossified segment of the OPLL and could lead to the progression of OPLL. The present cases showed that long-term progression of OPLL can induce neurological deterioration even after sufficient posterior decompression by laminoplasty. Therefore, when considering risk factors that may be predictive of the progression of OPLL after laminoplasty, it is important to perform strict follow-up examination to check for progression to reduce the risk of myelopathy symptoms that are indicative of neurological deterioration.

Analysis of Factors Contributing to Repeat Surgery in Multi-Segments Cervical Ossification of Posterior Longitudinal Ligament.

ObjectiveCervical ossification of the posterior longitudinal ligament (OPLL) can be treated via anterior or posterior approach, or both. The optimal approach depends on the characteristics of OPLL and cervical curvature. Although most patients can be successfully treated by a single surgery with the proper approach, renewed or newly developed neurological deterioration often requires repeat surgery.MethodsTwenty-seven patients with renewed or newly developed neurological deterioration requiring salvage surgery for multi-segment cervical OPLL were enrolled. Ten patients (group AP) underwent anterior approach, and 17 patients (group PA) underwent posterior approach at the initial surgery. Clinical and radiological data from initial and repeat surgeries were obtained and analyzed retrospectively.ResultsThe intervals between the initial and repeat surgeries were 102.80±60.08 months (group AP) and 61.00±8.16 months (group PA) (p<0.05). In group AP, the main OPLL lesions were removed during the initial surgery. There was a tendency that the site of main OPLL lesions causing renewed or newly developed neurological deterioration were different from that of the initial surgery (8/10, p<0.05). Repeat surgery was performed for progressed OPLL lesions at another segment as the main pathology. In group PA, the main OPLL lesions at the initial surgery continued as the main pathology for repeat surgery. Progression of kyphosis in the cervical curvature (Cobb’s angle on C2–7 and segmental angle on the main OPLL lesion) was noted between the initial and repeat surgeries. Group PA showed more kyphotic cervical curvature compared to group AP at the time of repeat surgery (p<0.05).ConclusionThe reasons for repeat surgery depend on the type of initial surgery. The main factors leading to repeat surgery are progression of remnant OPLL at a different segment in group AP and kyphotic change of the cervical curvature in group PA.

Radiological risk factors for progression of ossification of posterior longitudinal ligament following laminoplasty

Background ContextResearch shows the progression of ossification of the posterior longitudinal ligament (OPLL) following decompressive surgery for cervical myelopathy, particularly in cases presenting with continuous or mixed radiographic types. To date, no study has investigated OPLL progression within each motion segment. PurposeTo evaluate progression of cervical OPLL in each motion segment using a novel system of classification, and to identify risk factors for OPLL progression following laminoplasty. Study Design/SettingRetrospective case series. Patient SampleThis study included 34 patients (86 segments) with cervical myelopathy secondary to OPLL. Outcome MeasuresClinical and radiological data (plain radiographs and computed tomography [CT]) were obtained. MethodsClinical data from 34 patients (86 segments) with cervical myelopathy secondary to OPLL were evaluated retrospectively. All subjects had undergone laminoplasty at a single center. Sagittal reconstructive CT images were used to measure OPLL thickness in each segment. Ossified masses were classified into four types according to the degree of disc space involvement: type 1 (no involvement); type 2 (involving disc space but not crossing); type 3 (crossing disc space but not fused); and type 4 (complete bridging). Range of motion (ROM) for each segment was measured using dynamic radiographs. Statistical analyses were performed to determine the degree of OPLL progression according to the four disc space involvement types and ROM. ResultsMean OPLL progression was significantly higher in types 2 (1.3 mm) and 3 (1.5 mm) than in type 1 (0.5 mm) (p<.001). Severe progression (change in thickness >2 mm) was more frequent in types 2 (8 of 29) and 3 (7 of 16) than in types 1 (1 of 35) or 4 (0 of 6) (p=.002). In types 2 or 3, ROM>5° was correlated with severe OPLL progression (52% vs. 8%; p=.035). ConclusionsType 2 or 3 disc involvement and segmental ROM>5° were risk factors for OPLL progression. Classification of cervical OPLL according to disc involvement may help predict OPLL progression following laminoplasty. Close follow-up is warranted in cases of type 2 or 3 with greater segmental motion.

Rapid Progression of Ossification of the Posterior Longitudinal Ligament After Anterior Cervical Discectomy and Fusion

Ossification of the posterior longitudinal ligament (OPLL) has a reported incidence of 1.9%-4.3%. Disease progression is associated with surgery, with most studies focusing on OPLL progression after laminoplasty. The continued range of motion following surgery is believed to place strain on adjacent levels, driving calcification of the ligament. We present a case of marked progression of OPLL at levels adjacent to a previous anterior cervical discectomy and fusion. A 59-year-old man initially presented for progressive loss of balance and dexterity and underwent a C4-6 anterior cervical discectomy and fusion procedure. Computed tomography performed 1 year postoperatively showed fusion across C4-6 with no evidence of OPLL at any level. Two years following index surgery, the patient reported right-side arm pain. Computed tomography revealed new minimal OPLL opposite the C3-4 level that was not causing cord compression. A sparing midline bilateral C3-7 laminotomy was performed to correct stenosis seen on magnetic resonance imaging. At 7 years after the index procedure, the patient presented with myelopathic symptoms exceeding symptoms at his index presentation. Computed tomography revealed marked progression of OPLL. The patient underwent C2-T2 posterior fusion with laminectomy from C2-C7 and responded well with gradual improvements in balance and arm pain after surgery. Our report demonstrates that OPLL progression, which is largely reported following laminoplasty, may similarly occur following anterior cervical discectomy and fusion and supports the concept of motion-related OPLL progression.

Natural history of the ossification of cervical posterior longitudinal ligament: a three dimensional analysis.

Three-dimensional (3D) imaging using computed tomography (CT) has made it possible to accurately evaluate ossification of the posterior longitudinal ligament (OPLL). Recently, we developed a novel technique to measure ossification volume using the 3D analysis. The purpose of this study was to investigate the natural course of OPLL and the risk factors for volume progression. Forty-one patients (22 males and 19 females) diagnosed with cervical OPLL who had been non-surgically treated were included in this study. We evaluated clinical examination, radiological findings, and the volume of ossified lesions during at least 1-year intervals. Furthermore, we performed risk factor analysis for OPLL volume progression. The mean ossification volume was 2047.4±1437.3mm3 in the first examination and 2201.0±1524.1mm3 in the final examination, indicating a significant increase during the follow-up period (p<0.001). The mean annual rate of lesion increase was 4.1±2.7%. Univariate regression analysis demonstrated significant relationships between the annual rate of lesion increase and age (β=-0.48; p=0.001), body weight (BW) (β=0.36; p=0.02), and body mass index (BMI) (β=0.35; p=0.03). Furthermore, age was the only significant predictor of OPLL progression (R2=0.23; p=0.001) in multivariate liner regression analysis. Younger age, higher BW, and higher BMI are predictors of OPLL progression. Younger age is the most significant predictor in non-surgically treated patients.

Are There Differences in the Progression of Ossification of the Posterior Longitudinal Ligament Following Laminoplasty Versus Fusion?: A Meta-Analysis.

Systematic review and meta-analysis of studies for the treatment of cervical myelopathy with ossification of the posterior longitudinal ligament (OPLL) treated with laminoplasty or fusion. To delineate whether OPLL continues to progress after laminoplasty compared with fusion and to clarify the relationship between radiological progression of OPLL and neurological decline. Laminoplasty is usually performed in patients with multilevel OPLL due to the surgical morbidity of anterior surgery. However, the disadvantage of laminoplasty is that the remaining OPLL can progress after the surgery. A literature search of PubMed, Embase, Web of Science, and the Cochrane library was performed to identify investigations concerning the progression of OPLL after laminoplasty or fusion. The pooled results were analyzed by calculating the effect size based on the event rate and the logit event rate. We included data from 11 studies involving 530 patients, of whom 429 underwent laminoplasty and 101 underwent fusion surgery. The prevalence of radiological OPLL progression was 62.5% (95% confidence interval [CI] 55.3%-69.3%) for the laminoplasty group and 7.6% (95% CI 3.4%-15.9%) for the fusion group. The laminoplasty displayed substantially high prevalence of the progression of OPLL compared with the fusion group. In the laminoplasty group, the prevalence of OPLL progression increased with time and reached 60% at about 10-year follow-up. The prevalence for neurological decline was similar for about 2 years, 8.3% (95% CI 3.7%-17.9%) for the laminoplasty group and 3.8% (95% CI 1.3%-10.2%) for the fusion group. Laminoplasty frequently induces progression of OPLL compared with fusion surgery, but does not make significant clinical deterioration. However, laminoplasty may not be recommended for OPLL patient because it can be getting worse with time. 1.

Serum biomarkers in patients with ossification of the posterior longitudinal ligament (OPLL): Inflammation in OPLL.

BackgroudOssification of the posterior longitudinal ligament (OPLL) is characterized by replacement of ligamentous tissue by ectopic new bone formation. OPLL causes narrowing of the spinal canal, resulting in neurological impairment. However, the pathogenesis of OPLL has not been fully elucidated. We investigated whether inflammation occurs in OPLL or not using high-sensitivity CRP (hs-CRP) in a case-control study.Methods and findingsThis study included 103 patients with OPLL in the patient group and 95 age- and sex-matched volunteers with degenerative spinal disease in the control group. Of the 103 OPLL patients, 88 patients who were available for more than 2 years follow-up were checked for OPLL progression. A blood sample was obtained and Hs-CRP, and other routine data, including total protein (TP), albumin (ALB), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), glucose (Glu), calcium (Ca), inorganic phosphate (Pi), white blood cell count (WBC), hemoglobin (Hb) and platelet (PLT), were analyzed. The data were compared between the patients with OPLL and the controls. The severity of the ossified lesions in the whole spine were evaluated by the ossification index (OS index) in patients with OPLL. The data were also compared between the patients with OPLL progression (the progression group) and the patients without OPLL progression (the non-progression group). In the results, the mean hs-CRP in the OPLL group was higher than that in the controls. The Pi in the OPLL group was lower than that in the control group. A negative correlation was found between the Pi and the OS index. The mean hs-CRP in the progression group was higher than that in the non-progression group. There was a positive correlation between the average length of the OPLL progression per year and the hs-CRP.ConclusionsThe results may suggest the occurrence of local inflammation in OPLL and the inflammation might cause OPLL progression. These facts are important for understanding the pathology of OPLL.

Addition of instrumented fusion after posterior decompression surgery suppresses thickening of ossification of the posterior longitudinal ligament of the cervical spine

Laminoplasty (LMP) is a widely accepted surgical procedure for ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. Progression of OPLL can occur in the long term after LMP. The aim of the present study was to determine whether addition of the instrumented fusion, (posterior decompression with instrumented fusion [PDF]), can suppress progression of OPLL or not. The present study included 50 patients who underwent LMP (n=23) or PDF (n=27) for OPLL of the cervical spine. We performed open door laminoplasty. PDF surgery was performed by double-door laminoplasty followed by instrumented fusion. We observed the non-ossified segment of the OPLL and measured the thickness of the OPLL at the thickest segment with pre- and postoperative sagittal CT multi-planar reconstruction images. Postoperative CT scan revealed fusion of the non-ossified segment of the OPLL was obtained in 4/23 patients (17%) in the LPM group and in 23/27 patients (85%) in the PDF group, showing a significant difference between both groups (p=0.003). Progression of the thickness of the OPLL in the PDF group (−0.1±0.4mm) was significantly smaller than in the LMP group (0.6±0.7mm, p=0.0002). The proportion of patients showing the decrease in thickness of OPLL was significantly larger in the PDF group (6/27 patients; 22%) than in the LMP group (0/23 patients; 0%, p=0.05). In conclusion, PDF surgery can suppress the thickening of OPLL.

Integrated microRNA-mRNA analyses reveal OPLL specific microRNA regulatory network using high-throughput sequencing.

Ossification of the posterior longitudinal ligament (OPLL) is a genetic disorder which involves pathological heterotopic ossification of the spinal ligaments. Although studies have identified several genes that correlated with OPLL, the underlying regulation network is far from clear. Through small RNA sequencing, we compared the microRNA expressions of primary posterior longitudinal ligament cells form OPLL patients with normal patients (PLL) and identified 218 dysregulated miRNAs (FDR < 0.01). Furthermore, assessing the miRNA profiling data of multiple cell types, we found these dysregulated miRNAs were mostly OPLL specific. In order to decipher the regulation network of these OPLL specific miRNAs, we integrated mRNA expression profiling data with miRNA sequencing data. Through computational approaches, we showed the pivotal roles of these OPLL specific miRNAs in heterotopic ossification of longitudinal ligament by discovering highly correlated miRNA/mRNA pairs that associated with skeletal system development, collagen fibril organization, and extracellular matrix organization. The results of which provide strong evidence that the miRNA regulatory networks we established may indeed play vital roles in OPLL onset and progression. To date, this is the first systematic analysis of the micronome in OPLL, and thus may provide valuable resources in finding novel treatment and diagnostic targets of OPLL.

Posterior instrumented fusion suppresses the progression of ossification of the posterior longitudinal ligament: a comparison of laminoplasty with and without instrumented fusion by three-dimensional analysis.

There is no definitive evidence that additional instrumented fusion following laminoplasty suppresses the progression of ossification of the posterior longitudinal ligament (OPLL). Recently, we reported a novel method involving the creation of three-dimensional (3D) model from computed tomography images to measure the volume of OPLL accurately. The study aim was to evaluate whether laminoplasty with instrumented fusion suppresses the progression of OPLL in comparison with stand-alone laminoplasty by our novel 3D analysis. The present study comprised of a group of 19 patients (14 men, five women) with OPLL treated with posterior decompression and fusion (PDF group), and a group of 22 patients (14 men, eight women) treated with laminoplasty alone (LP group). The volume of OPLL was evaluated three times during the follow-up period, and the volume change of OPLL was compared between the two groups. The PDF group (2.0±1.7%/year; range, -3.0 to 5.3) demonstrated lower annual rate of lesion increase compared to the LP group (7.5±5.6%/year; range, 1.0-19.2) (p<0.001). In a notable thing, the annual rate of increase from the 2nd to the 3rd measurement significantly decreased compared with that from the 1st to the 2nd measurement in the PDF group (p<0.05). This is the first study to prove a possible suppressant effect of additional posterior instrumented fusion on OPLL progression using novel 3D analysis.

Analysis of progression of cervical OPLL using computerized tomography: typical sign of maturation of OPLL mass.

OBJECT The progression of cervical ossification of the posterior longitudinal ligament (OPLL) can lead to increase in the size of the OPLL mass and aggravation of neurological symptoms. In the present study, the authors aimed to analyze the progression of cervical OPLL by using CT imaging, elucidate the morphology of OPLL masses, and evaluate the factors associated with the progression of cervical OPLL. METHODS Sixty patients with cervical OPLL were included. All underwent an initial CT examination and had at least 24 months' follow-up with CT. The mean duration of follow-up was 29.6 months. Fourteen patients (Group A) had CT evidence of OPLL progression, and 46 (Group B) did not show evidence of progression on CT. The 2 groups were compared with respect to the following variables: sex, age, number of involved segments, type of OPLL, and treatment methods. The CT findings, such as the connection of an OPLL mass with the vertebral body and formation of trabeculation in the mass, were evaluated. RESULTS Sex and treatment modality were not associated with OPLL progression. The mean age of the patients in Group A was significantly lower than that in Group B (p = 0.03). The mean number of involved segments was 5.3 in Group A and 3.6 in Group B (p = 0.002). Group A had a higher proportion of cases with the mixed type of OPLL, whereas Group B had a higher proportion of cases with the segmental type (p = 0.02). A connection between the vertebral body and OPLL mass and trabeculation formation were more common in Group B (p < 0.01). CONCLUSIONS Progression of cervical OPLL is associated with younger age, involvement of multiple levels, and mixed-type morphology. OPLL masses that are contiguous with the vertebral body and have trabecular formation are useful findings for identifying masses that are less likely to progress.

Posterior Hybrid Technique for Ossification of the Posterior Longitudinal Ligament Associated With Segmental Instability in the Cervical Spine

Retrospective case series. To discuss the indications for a posterior hybrid technique for ossification of the posterior longitudinal ligament (OPLL) associated with segmental instability in the cervical spine and evaluate its effectiveness and safety. Dynamic factors have been shown to play an important role in the progression of ossification and OPLL myelopathy. Laminoplasty has been widely used to treat cervical OPLL, but progressive kyphosis and progression of ossified lesions are often detected in long-term follow-up. Fifteen patients were treated by a posterior hybrid technique including laminoplasty and lateral mass screw fixation at unstable levels. Preoperatively, the extent and type of OPLL, spinal cord compression, and presence of high-intensity zones were investigated by x-ray, computed tomography, and magnetic resonance imaging. Segmental instability in the cervical spine was investigated by dynamic x-ray. Postoperatively, clinical outcomes were evaluated with the Japanese Orthopedic Association scoring system and visual analog scale scores for neck pain. Radiologic results included cervical alignment and progression of OPLL. A total of 17 intervertebral levels in 15 patients (11 mixed-type and 4 continuous-type OPLL) had segmental instability, which was consistent with the presence of high-intensity zone levels in 10 (66.7%) patients. Neurological function as evaluated by the Japanese Orthopedic Association scores was significantly improved 6 months postoperatively and well maintained 4 years postoperatively. Neck pain was significantly improved 4 years postoperatively. No patients developed progressive kyphosis or progression of ossified lesions during the follow-up. Only 1 patient developed unilateral C5 palsy and completely recovered 2 months later. This hybrid posterior technique seems to be effective and safe in the treatment of selected patients with OPLL associated with segmental instability. The potential benefits of this technique include a stable environment for spinal cord recovery and prevention of progressive kyphosis and OPLL.