Ossification Of The Posterior Longitudinal Ligament Classification Research Articles

Foramen Facet Spinal Classification for Ossification of the Posterior Longitudinal Ligament on Computed Tomography: Closely Related to Clinical Efficacy.

Retrospective study. To develop and validate computed tomography (CT)-based classification schemes to eliminate ambiguity as much as possible and evaluate the adequacy and clinical value of its classification. There is no objective criteria for laminoplasty of more than one million Chinese patients with ossification of the posterior longitudinal ligament (OPLL) every year. CT imaging can accurately show the location, size, and shape of ossification, it is very important to propose a recognized simple classification of ossifications. From 2016 to 2018, 100 patients with "moderate to severe" OPLL on CT were performed according to the following criteria. This study simply classifies the grade of the ossification as 1-2-3, the zone is A-B by the foramen facet spinal canal classification, and the interexaminer reliability is 96%. A prospective series of 60 patients for laminoplasty was performed between 2018 and 2019, and this classification scheme was verified according to the new standard. All patients with size 1 were selectively excluded from consideration for surgery. The Japanese Orthopedic Association scores from both series are superior to most published results for patients with OPLL. The first and second series reported good to excellent results of 89% and 93.3%, respectively, and 80% and 85% for 24 months. The difference in the incidence of C5 paralysis and axial pain was statistically significant among the different zones, and most of them recovered within 6 months. The most common size and location types are 2-AB, 3-AB, and 2A. The most severe type is 3-AB. The foramen facet spinal classification of OPLL is a simple and reliable method for objectively evaluating the ossification of patients with OPLL based on CT research. Level III.

Improved diagnostic performance of plain radiography for cervical ossification of the posterior longitudinal ligament using deep learning.

BackgroundA high false-negative rate has been reported for the diagnosis of ossification of the posterior longitudinal ligament (OPLL) using plain radiography. We investigated whether deep learning (DL) can improve the diagnostic performance of radiologists for cervical OPLL using plain radiographs.Materials and methodsThe training set consisted of 915 radiographs from 207 patients diagnosed with OPLL. For the test set, we used 200 lateral cervical radiographs from 100 patients with cervical OPLL and 100 patients without OPLL. An observer performance study was conducted over two reading sessions. In the first session, we compared the diagnostic performance of the DL-model and the six observers. The diagnostic performance was evaluated using the area under the receiver operating characteristic curve (AUC) at the vertebra and patient level. The sensitivity and specificity of the DL model and average observers were calculated in per-patient analysis. Subgroup analysis was performed according to the morphologic classification of OPLL. In the second session, observers evaluated the radiographs by referring to the results of the DL-model.ResultsIn the vertebra-level analysis, the DL-model showed an AUC of 0.854, which was higher than the average AUC of observers (0.826), but the difference was not significant (p = 0.292). In the patient-level analysis, the performance of the DL-model had an AUC of 0.851, and the average AUC of observers was 0.841 (p = 0.739). The patient-level sensitivity and specificity were 91% and 69% in the DL model, and 83% and 68% for the average observers, respectively. Both the DL-model and observers showed decreases in overall performance in the segmental and circumscribed types. With knowledge of the results of the DL-model, the average AUC of observers increased to 0.893 (p = 0.001) at the vertebra level and 0.911 (p < 0.001) at the patient level. In the subgroup analysis, the improvement was largest in segmental-type (AUC difference 0.087; p = 0.002).ConclusionsThe DL-based OPLL detection model can significantly improve the diagnostic performance of radiologists on cervical radiographs.

The Effect of Laminectomy with Instrumented Fusion Carried into the Thoracic Spine on the Sagittal Imbalance in Patients with Multilevel Ossification of the Posterior Longitudinal Ligament.

ObjectiveTo determine if there is a difference in either the cervical alignment or the clinical outcomes in cervical ossification of the posterior longitudinal ligament (OPLL) patients who underwent laminectomy with instrumented fusion (LIF) ending at C6, C7, or proximal thoracic spine for the treatment of multilevel OPLL, and to find out the appropriate distal fusion level.MethodsThis was a single‐center retrospective study. In total, 36 patients with cervical OPLL who underwent three or more level LIF in our institution between January 2015 and January 2017 were enrolled. They were divided into three groups according to their distal ends: C6 (nine females and 11 males, 60.45 ± 9.68 years old), C7 (four females and six males, 61.60 ± 10.29 years old), and T‐group (two females and four males, 64.33 ± 8.12 years old). Radiographic (compression level, classification of OPLL, occupying rate, C2‐7 cobb angle, C2‐7 sagittal vertical axis, and fusion level) and clinical outcomes (NDI score, operative time, and blood loss) were compared. Predictors of postoperative sagittal imbalance were also identified according to if the postoperative C2‐7 SVA was greater than 40 mm. The sensitivity and specificity of preoperative parameters predicting postoperative cervical stability were evaluated via the receiver operating characteristic (ROC) curve.ResultsAll patients were followed up at least 1 year. The blood loss in T group was significantly more than C6 or C7 group. The length of fusion level became significantly longer when the caudal level extended to the thoracic spine. The age, preoperative SVA, and NDI score at follow‐up were significantly greater in the imbalance group. At the final follow‐up, the cervical lordosis tended to be straight and the C2‐7 SVA tended to be greater when the caudal level of fusion was extended to upper thoracic segment. Further ROC curve analysis suggested that patients’ age had a sensitivity of 75.00%, specificity of 79.17% for cervical stability, and the AUC was 0.844 (P < 0.01), with the cutoff value for age being 66.5 years old. For preoperative SVA, the sensitivity was 58.30%, and specificity was 91.70%, with the AUC of 0.778 (P < 0.01). The cutoff value for preoperative SVA was 30.4 mm.ConclusionAlthough posterior fusion terminating in the thoracic spine was not superior to the cervical spine for patients with multilevel OPLL, for elderly patients (>67 years) with great preoperative SVA (>30 mm), terminating at C6 was recommended to limit the invasion of cervical extensor muscles, provided the decompression was adequate.

Use of residual neural network for the detection of ossification of the posterior longitudinal ligament on plain cervical radiography.

Ossification of the posterior longitudinal ligament (OPLL) causes serious problems, such as myelopathy and acute spinal cord injury. The early and accurate diagnosis of OPLL would hence prevent the miserable prognoses. Plain lateral radiography is an essential method for the evaluation of OPLL. Therefore, minimizing the diagnostic errors of OPLL on radiography is crucial. Image identification based on a residual neural network (RNN) has been recognized to be potentially effective as a diagnostic strategy for orthopedic diseases; however, the accuracy of detecting OPLL using RNN has remained unclear. An RNN was trained with plain lateral cervical radiography images of 2,318 images from 672 patients (535 images from 304 patients with OPLL and 1,773 images from 368 patients of Negative). The accuracy, sensitivity, specificity, false positive rate, and false negative rate of diagnosis of the RNN were calculated. The mean accuracy, sensitivity, specificity, false positive rate, and false negative rate of the model were 98.9%, 97.0%, 99.4%, 2.2%, and 1.0%, respectively. The model achieved an overall area under the curve of 0.99 (95% confidence interval, 0.97-1.00) in which AUC in each fold estimated was 0.99, 0.99, 0.98, 0.98, and 0.99, respectively. An algorithm trained by an RNN could make binary classification of OPLL on cervical lateral X-ray images. RNN may hence be useful as a screening tool to assist physicians in identifying patients with OPLL in future setting. To achieve accurate identification of OPLL patients clinically, RNN has to be trained with other cause of myelopathy.

A STUDY OF RELATIONSHIP BETWEEN SERUM ESR AND CRP IN PATIENTS WITH OSSIFICATION OF POSTERIOR LONGITUDINAL LIGAMENT

Ossification of the posterior longitudinal ligament (OPLL) is seen most commonly in men, in the elderly, and in Asian population [1].The disease usually starts with minimal or no symptoms, but some patients slowly progress to develop symptoms of myelopathy and radiculopathy.The present study aims to find out the relationship between serum CRP and ESR levels in patients with OPLL and its relationship with radiological classification of OPLL. In this cross sectional correlation study we have included all patients fulfilling the inclusion criteria from the year July 2019 to December 2020 in tertiary care hospital.Our study comprising of total 50 patients will show the relationship between OPLL with level of serum CRP and ESR (normal or raised).In our study it was found that majority of the patients were above 50 years of age with male predominance.In the present study it was found that the level of CRP was raised in 83.4% cases of continuous type,100% cases of localised type,69.2% cases of mixed type and 92.8% cases of segmental type.In the present study it was found that the level of ESR was raised in 83.4% cases of continuous type,66.7% cases of localised type,61.5% cases of mixed type and 75.0% cases of segmental type. It is possible that raised serum levels of CRP and ESR may be associated with OPLL and thus inflammation may be the cause of OPLL.

Modified axial computed tomography classification of cervical ossification of the posterior longitudinal ligament: selecting the optimal operating procedure and enhancing the accuracy of prognosis.

Cervical ossification of the posterior longitudinal ligament (OPLL) causes spinal cord compression, which can lead to myelopathy or radiculopathy. Non-surgical treatments have little effect on this condition. Current OPLL classification systems offer little guidance on the selection of an appropriate operating procedure. In this study, we developed a modified axial computed tomography classification (MACTC) scheme. We then examined the usefulness of the MACTC scheme and two other existing classification schemes in guiding OPLL operation choice. Following screening in which a defined exclusion criteria was used, a total of 91 patients with OPLL participated in the study. Patients' follow-up data for at least 2 years were obtained. The recovery rate of the Japanese Orthopaedic Association (JOA) scores was compared to two other classification schemes. According to the MACTC, central-sharp-type OPLL had a lower recovery rate of the JOA score than that of central-gentle-type OPLL (36.05±32.38 vs. 83.90±23.52, P≤0.05). The recovery rate of the JOA scores in the ipsilateral open-door OPLL group was significantly lower than that in the contralateral group of the lateral-steep type (36.67±41.5 vs. 88.89±17.21, P=0.04), but not of that in the lateral-gentle type. There was no significant difference in the recovery rates of the JOA scores between groups when using either existing classification scheme (P>0.05). The MACTC scheme can assist surgeons to choose the most appropriate operating procedure, and provide an accurate prognosis. If operations on central-sharp-type OPLL are not performed using both the posterior and anterior approaches, prognosis will be poor. The contralateral side should be the first choice for door opening in laminoplasty, especially for patients with lateral-steep-type OPLL. Severe OPLL may not be an absolute contraindication for the posterior approach.

Influence of K-line on intraoperative and hidden blood loss in patients with ossification of the posterior longitudinal ligament when undergoing unilateral open-door laminoplasty

BackgroundThe K-line is a virtual straight line that connects the midpoints of the anteroposterior spinal canal diameter from C2 to C7 on a cervical lateral X-ray film. Patients with cervical ossification of the posterior longitudinal ligament (OPLL), in which the peak of the OPLL exceeds the K-line (K-line [-]), are less likely to experience sufficient decompression after laminoplasty compared with patients for whom the OPLL does not exceed the K-line (K-line [+]). This retrospective study investigated the influence of K-line position relative to the OPLL on intraoperative and hidden blood loss during unilateral open-door laminoplasty for OPLL.MethodsData were retrospectively analyzed of 108 patients with OPLL who underwent unilateral open-door laminoplasty between April 2015 and March 2018. Patient cases were categorized as K-line (+) or (-). The evaluated perioperative parameters were haematocrit, haemoglobin, intraoperative and hidden blood loss, surgical time, postoperative drainage, and complications. Radiological parameters included ossification occupancy ratio and C2-7 lordosis.ResultsThe K-line (+) and K-line (-) groups were statistically comparable with regard to age, gender, body mass index, OPLL classification, medication history, C2-7 lordosis, postoperative haemoglobin and haematocrit, postoperative drainage, hidden blood loss, and complications. The occupying ratio of the K-line (-) group was significantly greater than that of the K-line (+) group (49.5 ± 15.3% cf. 42.3 ± 10.1%; P = 0.006), and the intraoperative blood loss was also significantly higher (286 ± 110.5 mL cf. 205.5 ± 98.3 L, P = 0.003). The hidden blood loss of the K-line (-) group was higher than that of the K-line (+), but not significantly (295.5 ± 112.6 mL cf. 265.6 ± 103.8 mL; P = 0.072).ConclusionIntraoperative and hidden blood loss associated with unilateral open-door laminoplasty can be predicted by the spatial relationship of the K-line and osteophyte. This relationship is a simple and practical index that may help surgeons determine the appropriate surgical strategy for patients with OPLL.

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

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. 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. 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. 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.

Cervical Ossification of the Posterior Longitudinal Ligament: A Computed Tomography-Based Epidemiological Study of 2917 Patients.

Study Design:Retrospective cohort study.Objectives:To identify prevalence of ossification of the posterior longitudinal ligament (OPLL) of the cervical spine in a large sample, to characterize spinal involvement, and to identify associations with patient characteristics.Methods:Computed tomography (CT) scans of all patients receiving cervical spine CT imaging in a level-1 emergency department from January 1, 2014 to December 31, 2014 were reviewed. Diagnosis and classification of OPLL was performed, and data for associated patients was obtained (age, sex, race, ethnicity, body mass index, diabetes). US Census data was referenced for the sample population. Statistical analysis included t test and chi-square testing, with significance cutoff P < .05.Results:There were no significant differences between the sample and population data. Of 2917 patients reviewed, 74 exhibited OPLL (2.5%). Age distribution between OPLL and non-OPLL cohorts was significantly different (P < .01), with highest prevalence of OPLL between ages 40 to 49 and 50 to 59 years. Comorbid diabetes also differed between groups (27% OPLL, 13% non-OPLL, P < .01). There was no difference in distribution of sex, race, or ethnicity. For OPLL, segmental type is most common (67.6%), involving on average 3.4 levels. OPLL involvement begins at any level, but ends most commonly at C6 (40.5%) or C7 (36.5%). Among OPLL patients, 18 (24.3%) demonstrated concurrent ponticulus posticus.Conclusions:This review of 2917 patients reaffirms previous data, with OPLL prevalence of 2.5%. In asymptomatic patients, incidental diagnosis is frequently seen as early as ages 40 to 49 years. OPLL is better characterized with a significant association with diabetes, segmental type being the most common, and the caudal extent typically involving C6-7 (77%).

What Are the Important Predictors of Postoperative Functional Recovery in Patients With Cervical OPLL? Results of a Multivariate Analysis

Study Design:A retrospective cohort study.Objective:The objective of this study was to identify important predictors of poor functional recovery in patients undergoing surgery for cervical ossification of the posterior longitudinal ligament (OPLL).Methods:This was a retrospective cohort study of 142 OPLL patients with laminoplasty; 135 had complete radiographical data and were followed up for ≥2 years. The following OPLL characteristics were compared between patients with “good” and “poor” outcomes (Japanese Orthopedic Association [JOA] recovery rate ≥50% and <50%, respectively): number of ossified levels, OPLL classification, ossification shape, K-line, canal-occupying ratio, and increased magnetic resonance imaging (MRI) signal intensity. Predictors of functional recovery were identified.Results:Pre- and postoperative (2 years following surgery) JOA scores were 10.6 ± 2.9 and 14.1 ± 2.2, respectively, indicating significant improvement following laminoplasty (P < .001). The average JOA recovery rate was 53.4% ± 34.7%, with 81 (60.0%) and 54 (40.0%) patients in the better and poorer neurological outcome groups, respectively. The canal occupation ratio of OPLL ≤60%/>60% were 117 (86.7%) and 18 (13.3%) patients, respectively. In the stepwise logistic regression analysis, an occupation ratio greater than 60% was identified as a significant factor for poor postoperative neurological outcome (relative risk, 4.82; 95% confidential interval, 1.61-14.46, P = .005).Conclusions:This multivariate analysis demonstrated a large size OPLL (occupying ratio >60%) was associated with a risk of poor neurological recovery roughly 5 times greater, and therefore other types of surgery are recommended in cases with such a ratio.

Three-dimensional evaluation of volume change in ossification of the posterior longitudinal ligament of the cervical spine using computed tomography

Two-dimensional imaging is not adequate for evaluating ossification of the posterior longitudinal ligament (OPLL). This study was designed to evaluate the accuracy of a novel computed tomography (CT)-based three-dimensional (3D) analysis method that we had devised to measure volume changes in OPLL. Twenty OPLL patients (12 male and 8 female; mean age 63.6 years) who were being followed conservatively were examined twice with an interval of at least 1 year between the two scans. The mean interval was 22 (range 12-45) months. A 3D model was created with DICOM data from CT images, using the MIMICS(®) software to calculate the volume. The mean ossification volume was determined from two measurements. Since ossification size varies widely, evaluation of change in volume is generally affected by the original size. Therefore, the change in ossification volume between the first and second CT examinations was calculated as the annual rate of progression. The type of OPLL was classified as continuous in 3 patients, segmented in 3, and mixed in 14. The mean ossification volume was 1,831.68 mm(3) at the first examination and 1,928.31 mm(3) at the second, showing a significant mean increase in ossification volume. The mean annual rate of lesion increase was 3.33% (range 0.08-7.79%). The 3D method used allowed detailed OPLL classification and quantification of change in the ossified volume. Thus, this method appears to be very useful for quantitative evaluation of OPLL with only minimal measurement error.

Use sagittal reconstruction CT for making decisions regarding the surgical strategy for cervical ossification of the posterior longitudinal ligament

Use sagittal reconstruction CT to verify the surgical strategy for cervical ossification of the posterior longitudinal ligament (OPLL). A retrospective study of 161 patients (106 males and 55 females) who had undergone surgery for OPLL from July 2007 to November 2010 was performed. The mean age at surgery was 54.5 years (range from 26 to 77 years). The mean follow-up period was 28 months (12 - 54 months). There were 40 patients accept anterior approach surgeries (anterior group) which include 14 cases of anterior cervical corpectomy and fusion and 26 cases of anterior cervical discectomy and fusion. There were 120 patients accept posterior approach surgeries (posterior group) which was spinous process-splitting laminoplasty for cervical myelopathy using coralline hydroxyapatite. One patient accepted combined anterior and posterior approach. According to the sagittal reconstruction CT, the main reason for spinal cord compression was cervical disc herniation in anterior group, and OPLL in posterior group. The level of spinal cord compression was 1 to 2 levels in anterior group, and 1 to 5 levels in posterior group with a major of 2 to 4 levels. As the classification of OPLL, segmental type and circumscribed type were major of segmental type in anterior group and all of the four types were in posterior group, the distribution of each type was average. The patients of posterior group were classified into two groups according to the modified K-line classification, and clinical results were compared between the two groups. The modified K-line was defined as a line that connects the midpoints of the spinal canal at C(2) and C(7) on sagittal CT myelography. Compression to the spinal cord did not exceed the K-line in the modified K-line(+) group and did exceed it in the modified K-line(-) group. Clinical data were compared using t-test or χ(2) test. Correlation analysis was used to determine the relationships of C(2)-C(7) angulation between sagittal reconstruction CT and neutral position X-ray. The patient of anterior group had better recovery rate of the JOA score (72% ± 27%) than the posterior group (59% ± 35%) at the latest follow-up (t = 2.238, P = 0.027). In posterior group, the patients of modified K-line(+) group had better recovery rate of the JOA score (63% ± 37%) than the K-line(-) group (49% ± 30%) at the latest follow up (t = 2.150, P = 0.034). The C(2)-C(7) angulation on sagittal reconstruction CT was 11° ± 9° which has significantly correlated with the C(2)-C(7) angulation on neutral position X-ray which was 10° ± 10° (r = 0.947, P < 0.01). Considering the selection of surgical approach, it should be combined with the main clinical diagnosis for spinal cord compression, the level of compression, the classification of OPLL and the kyphotic alignment of the cervical spine. The modified K-line is a simple and practical tool for making decisions regarding the surgical strategy for cervical OPLL patients.

Inter- And Intra-observer Variability Of A Cervical OPLL Classification Using Reconstructed CT Images

BackgroundThe lateral radiograph-based system described by Tsuyama is used widely to classify ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. However, OPLL is a complex 3-dimensional (3-D) lesion, not a simple and uniplanar one, which is often difficult to identify on a lateral radiograph. Furthermore, its reliability among spine surgeons has not been investigated. Given the popularity of a reconstructed computed tomography (CT), this study examined the inter- and intra-observer reliability of lateral radiograph-based OPLL classification using that modality.MethodsFive spine surgeons independently reviewed the lateral radiograph, axial CT, 2-D (sagittal) and 3-D reconstructed CT images of 108 OPLL patients on 2 separate occasions. Based on these images, the reviewers classified each OPLL case according to the Tsuyama's system. The kappa values were used to assess the statistical reliability.ResultsThe inter- and intra-observer kappa values were only 0.51 and 0.67 for the lateral radiograph, even in combination with the axial CT images, 0.70 and 0.85 for 2-D CT images, and 0.76 and 0.86 for 3-D CT images, respectively. These kappa values showed a good-to-excellent range for the 2-D and 3-D reconstructed CT images while those of the lateral radiograph indicated a fair range. According to the OPLL types, the inter- and intra-observer reliability was low in the continuous type and high in the circumscribed type on the lateral radiograph. However, the low reliability of the continuous type on lateral radiograph was overcome somewhat using 2-D and 3-D reconstructed CT images.ConclusionsThe inter- and intra-observer kappa values were only 0.51 and 0.67 for the lateral radiograph, even in combination with the axial CT images, 0.70 and 0.85 for 2-D CT images, and 0.76 and 0.86 for 3-D CT images, respectively. These kappa values showed a good-to-excellent range for the 2-D and 3-D reconstructed CT images while those of the lateral radiograph indicated a fair range. According to the OPLL types, the inter- and intra-observer reliability was low in the continuous type and high in the circumscribed type on the lateral radiograph. However, the low reliability of the continuous type on lateral radiograph was overcome somewhat using 2-D and 3-D reconstructed CT images.