Ossification of posterior longitudinal ligament of the cervical spine in non-Japanese Asians

The significance of metabolic disease in degenerative cervical myelopathy: a systematic review

Introduction

Degenerative cervical myelopathy (DCM) is a form of chronic spinal cord injury, with a natural history of potential for progression over time. Whilst driven by mechanical stress on the spinal cord from degenerative and congenital pathology, the neurological phenotype of DCM is likely to be modified by multiple systemic factors. The role of metabolic factors is therefore of interest, particularly given that ischaemia is considered a key pathological mechanism of spinal cord injury. The objective was therefore to synthesise current evidence on the effect of metabolism on DCM susceptibility, severity, and surgical outcomes.

Methods

A systematic review in MEDLINE and Embase was conducted following PRISMA guidelines. Full-text papers in English, with a focus on DCM and metabolism, including diabetes, cardiovascular disease, anaemia, and lipid profile, were eligible for inclusion. Risk of methodological bias was assessed using the Joanna Briggs Institute (JBI) critical assessment tools. Quality assessments were performed using the GRADE assessment tool. Patient demographics, metabolic factors and the relationships between metabolism and spinal cord disease, spinal column disease and post-operative outcomes were assessed.

Results

In total, 8,523 papers were identified, of which 57 met criteria for inclusion in the final analysis. A total of 91% (52/57) of included papers assessed the effects of diabetes in relation to DCM, of which 85% (44/52) reported an association with poor surgical outcomes; 42% of papers (24/57) discussed the association between cardiovascular health and DCM, of which 88% (21/24) reported a significant association. Overall, DCM patients with diabetes or cardiovascular disease experienced greater perioperative morbidity and poorer neurological recovery. They were also more likely to have comorbidities such as obesity and hyperlipidaemia.

Conclusion

Metabolic factors appear to be associated with surgical outcomes in DCM. However, evidence for a more specific role in DCM susceptibility and severity is uncertain. The pathophysiology and natural history of DCM are critical research priorities; the role of metabolism is therefore a key area for future research focus.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42021268814.

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.

Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire as an outcome measure for ossification of posterior longitudinal ligament patients in East Asia: an investigation of reliability, validity, and responsiveness

Background

The surgical outcomes of individual patient with ossification of the posterior longitudinal ligament (OPLL) can vary depending on various patient-related factors. Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) is a well-developed tool for outcome measurement and considers both disease-specific and general health aspects. This study aimed to investigate the reliability, validity, and responsiveness of the JOACMEQ in patients with OPLL in mainland China and to compare post-operative outcomes of OPLL patients between mainland China and Japan.

Methods

This multicenter trial was performed between July 2009 and June 2019. The procedure for the JOACMEQ translation followed Beaton’s guidelines. All patients enrolled were diagnosed with OPLL and had completed the JOACMEQ, the modified Japanese Orthopaedic Association (mJOA) scale, and the 36-Item Short Form Health Survey (SF-36) before and after surgery. The reliability (Cronbach’s α and Pearson’s correlation), construct validity (factor analysis), concurrent validity (Spearman’s correlation with SF-36) and responsiveness (effect sizes) of JOACMEQ were evaluated. A mixed-model analytic approach was used to analyze differences in postoperative outcomes between the 2 countries.

Results

Ninety-one patients from mainland China and ninety-one patients from Japan were recruited. JOACMEQ showed satisfactory internal consistency (Cronbach’s α=0.75). In test-retest reliability evaluation, except for the bladder function domain, the JOACMEQ domains had good test-retest reliability (0.89–0.96). In factor analysis, most of the items (19/24) were well clustered. Regarding clinical validity, all 5 domains were found to have moderate correlations with the physical component summary (PCS) of SF-36 (r=0.25–0.50), and the bladder function and quality of life domains also had moderate correlations (r=0.25–0.50) with the mental component summary (MCS) of SF-36. JOACMEQ showed a variable responsiveness in different domains (effect size =0.17–0.84; standardized response means =0.15–0.85). Regarding postoperative improvements in the JOACMEQ score, mixed-model analysis revealed a significant difference in the quality of life domain between Chinese and Japanese patients (16.0±18.7 vs. 7.8±17.7, P<0.05).

Conclusions

JOACMEQ generally shows good reliability, good validity and mild responsiveness, and can identify the post-operative improvements in patients with OPLL in mainland China. Chinese OPLL patients showed a significantly larger improvement in postoperative quality of life compared to their Japanese counterparts.

Diagnostic Delays Lead to Greater Disability in Degenerative Cervical Myelopathy and Represent a Health Inequality

STUDY DESIGN

Online survey.

OBJECTIVE

This study seeks to quantify delays faced, determine demographics of patients most likely to face delay, and determine whether delays affect surgical management and outcomes.

SUMMARY OF BACKGROUND DATA

Patients report significant delays in diagnosis of degenerative cervical myelopathy (DCM).

METHODS

Seven hundred seventy-eighty patients with self-reported DCM recruited via online survey hosted on myelopathy.org. A cumulative odds ordinal logistic regression was run to determine the effects of demographic (sex, country of residence, ethnicity, household income, and educational status) on the delay in diagnosis of DCM. Chi-square tests of homogeneity were run to determine the effects of delayed diagnosis on functional outcomes (patient-derived modified Japanese Orthopaedic Association disability score, support dependence, and employment status) and surgical management (anterior/posterior approach, single-/multilevel surgery). A Kruskal-Wallis H test was used to determine whether delayed diagnosis affected the number of operations undergone.

RESULTS

The average delay in diagnosis faced was "1-2 years.' Greater delays in diagnosis were faced by Black or African American patients (P = 0.010). Delayed diagnosis was predictive of greater disability as assessed by patient-derived modified Japanese Orthopaedic Association score (P = 0.001), support dependence (P = 0.040), and employment status (P < 0.0005). Delayed diagnosis did not affect the likelihood of surgery, the number of operations undergone or perioperative characteristics.

CONCLUSION

Patients continue to face significant delays in diagnosis of DCM. Ethnicity significantly influences length of delay experienced. Longer delays do not appear to affect surgical management but are associated with greater disability.

LEVEL OF EVIDENCE

3.

Ossification of Posterior Longitudinal Ligament of Cervical Spine Among Omani Patients Referred for CT Scan at a Tertiary Care Hospital in Oman

Objectives

We sought to evaluate the proportion of ossification of the posterior longitudinal ligament (OPLL) of the cervical spine and associated factors among Omani patients.

Methods

We reviewed the cervical spine computed tomography (CT) scans of all patients referred to the Radiology Department, Sultan Qaboos University Hospital, from 2011 to 2017. Descriptive statistics were employed to determine the proportion of OPLL. We used the chi-square test to determine the association of age, gender, and diabetes mellitus with OPLL.

Results

A total of 843 patients aged ≥ 20 years were included in the study. The proportion of OPLL was 2.7% and was more frequent in men (3.2%) than women (1.9%). The male to female ratio of OPLL was 1.7:1.0. OPLL occurrence was significantly more in non-diabetic patients (p < 0.001). No significant association was found between OPLL with gender (p = 0.281) and age (p = 0.878).

Conclusions

The observed proportion of OPLL in this single-center study is relatively low, but the finding is important as the condition can eventually lead to debilitating neurologic outcomes affecting the patient's quality of life. OPLL occurrence was significantly more in non-diabetic patients, which necessitate further research on OPLL in a larger sample across Oman.

Inter- and Intra-Observer Variability of the Volume of Cervical Ossification of the Posterior Longitudinal Ligament Using Medical Image Processing Software

Objective

Computed tomography (CT)-based method of three dimensional (3D) analysis (MIMICS^®, Materialise, Leuven, Belgium) is reported as very useful software for evaluation of OPLL, but its reliability and reproducibility are obscure. This study was conducted to evaluate the accuracy of MIMICS^® system, and inter- and intra-observer reliability in the measurement of OPLL.

Methods

Three neurosurgeons independently analyzed the randomly selected 10 OPLL cases with medical image processing software (MIMICS^®) which create 3D model with Digital Imaging and Communication in Medicine (DICOM) data from CT images after brief explanation was given to examiners before the image construction steps. To assess the reliability of inter- and intra-examiner intraclass correlation coefficient (ICC), 3 examiners measured 4 parameters (volume, length, width, and length) in 10 cases 2 times with 1-week interval.

Results

The inter-examiner ICCs among 3 examiners were 0.996 (95% confidence interval [CI], 0.987–0.999) for volume measurement, 0.973 (95% CI, 0.907–0.978) for thickness, 0.969 (95% CI, 0.895–0.993) for width, and 0.995 (95% CI, 0.983–0.999) for length. The intra-examiner ICCs were 0.994 (range, 0.991–0.996) for volume, 0.996 (range, 0.944–0.998) for length, 0.930 (range, 0.873–0.947) for width, and 0.987 (range, 0.985–0.995) for length.

Conclusion

The medical image processing software (MIMICS^®) provided detailed quantification OPLL volume with minimal error of inter- and intra-observer reliability in the measurement of OPLL.

Cervical Myelopathy Secondary to Ossification of the Posterior Longitudinal Ligament in a Caucasian Patient

Cervical myelopathy consequent on ossification of posterior longitudinal ligament (OPLL) is very rare in Caucasians. A 65-year-old Anglo-Saxon woman developed progressive gait disturbance, paresthesia in both legs and urinary urge incontinence. Radiological examination showed OPLL from fifth to seventh cervical vertebral level; the dense OPLL was graphically displayed by three-dimensional computerized tomography. Medial corpectomy, C5 to C7, and removal of OPLL, with subsequent fusion C4 to Tl using a free fibula graft resulted in clinical improvement. Three dimensional computerized tomographic imaging is a valuable diagnostic procedure in OPLL.

Clinics in diagnostic imaging (161). Cervical OPLL with cord compression

A 53-year-old man presented with acute cervical myelopathy following a fall. Cervical radiography and computed tomography showed ossification of the posterior longitudinal ligament (OPLL) from C2 to C6 level, with severe cervical canal stenosis and cord compression. Magnetic resonance imaging further showed increased T2-weighted signal in the spinal cord at the level of greatest central spinal canal stenosis. OPLL is a significant cause of myelopathy in Asian populations and is found in up to 25% of patients presenting with cervical compression myelopathy. The clinical presentation, radiological evaluation and management of OPLL are discussed.

Ossification of the posterior longitudinal ligament of the cervical spine in 3161 patients: a CT-based study

STUDY DESIGN

A cross-sectional study.

OBJECTIVE

To examine the prevalence of ossification of the posterior longitudinal ligament (OPLL) and ossification of the nuchal ligament (ONL) of the cervical spine in the San Francisco area.

SUMMARY OF BACKGROUND DATA

The prevalence of OPLL and ONL is unknown in the non-Asian population.

METHODS

This computed tomography-based cross-sectional study assessed the prevalence of OPLL and ONL within the cervical spine of patients treated at a level 1 trauma center between 2009 and 2012. The prevalence of both OPLL and ONL was compared between racial groups.

RESULTS

Of the 3161 patients (mean age, 51.2 ± 21.6 yr; 66.1% male), there were 1593 Caucasians (50.4%), 624 Asians (19.7%), 472 Hispanics (14.9%), 326 African Americans (10.3%), 62 Native Americans (2.0%), and 84 Others (2.7%). The prevalence of cervical OPLL was 2.2% (95% confidence interval [CI]: 1.7-2.8). The adjusted prevalence was 1.3% in Caucasian Americans (95% CI: 0.7-2.3), 4.8% in Asian Americans (95% CI: 2.8-8.1), 1.9% in Hispanic Americans (95% CI: 0.9-4.0), 2.1% in African Americans (95% CI: 0.9-4.8), and 3.2% in Native Americans (95% CI: 0.8-12.3). The prevalence of OPLL in Asian Americans was significantly higher than that in Caucasian Americans (P = 0.005). ONL was detected in 346 patients and the prevalence was 10.9% (95% CI: 10.0-12.0). The adjusted prevalence of ONL was 7.3% in Caucasian Americans (95% CI: 5.8-9.3), 26.4% in Asian Americans (95% CI: 21.9-31.5), 7.4% in Hispanic Americans (95% CI: 5.2-10.5), 2.5% in African Americans (95% CI: 1.2-4.9), and 25.8% in Native Americans (95% CI: 16.5-37.5). ONL was significantly more common in Asian Americans than in Caucasian Americans, Hispanic Americans, and African Americans (P = 0.001).

CONCLUSION

This study also demonstrated that OPLL and ONL were significantly more common in Asian Americans than in Caucasian Americans.

LEVEL OF EVIDENCE

3.

Association of VKORC1-1639G>A polymorphism with susceptibility to ossification of the posterior longitudinal ligament of the spine: a Korean study

BACKGROUND

Abnormalities of bone metabolism may be involved in the pathogenesis of ossification of the posterior longitudinal ligament (OPLL) of the spine. Besides its hemostatic effect, vitamin K epoxide reductase complex subunit 1 (VKORC1) plays a pivotal role in bone mineralization. The aim of this study is to investigate whether single nucleotide polymorphisms (SNPs) of the VKORC1 gene are associated with the occurrence of OPLL in a Korean population.

METHOD

A total of 98 patients with OPLL and 200 controls were genotyped for the VKORC1-1639G>A SNP (rs9923231) by polymerase chain reaction and restriction fragment length polymorphism analysis. All the patients (n = 98) in this study underwent surgery (60, posterior-only approach; 36, anterior-only approach; 2, combined anterior and posterior approach) during their admission. We analyzed this association separately according to the gender and OPLL subgroup: OPLL continuous group (continuous type plus mixed type) and OPLL segmental group (segmental and localized type).

RESULTS

We found that the genotype VKORC1-1639G>A frequency was significantly associated with the occurrence of the OPLL in the female group (adjusted odds ratio = 5.22, 95 % confidence interval: 1.675 to 16.269, p = 0.004). However, there was no overall association between the OPLL susceptibility and VKORC1-1639G>A polymorphism. A subgroup analysis did not show any significant correlation between VKORC1-1639G>A polymorphism and subgroup of OPLL either.

CONCLUSION

Our results suggest that the VKORC1-1639G>A SNP may increase susceptibility to OPLL in women. However, there was only a statistical association in the female group despite a number of stratified analyses. Therefore, the findings should be interpreted with caution, and further genetic study is needed to improve our understanding of the role of VKORC1 polymorphisms in determining the risk of OPLL occurrence.

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

BACKGROUND

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.

SUBJECTS AND METHODS

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.

RESULTS

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%).

CONCLUSION

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.

Analysis of demographics, clinical, and radiographical findings of ossification of posterior longitudinal ligament of the cervical spine in 146 Korean patients

STUDY DESIGN

Retrospective clinical data analysis.

OBJECTIVE

This study was conducted to analyze retrospectively the demographics, clinical presentation, and radiographical findings of ossification of posterior longitudinal ligament (OPLL) of the cervical spine in Korean patients, which could serve as a basis for further studies on and treatment of OPLL.

SUMMARY OF BACKGROUND DATA

As the frequency of diagnosing the OPLL has been gradually increasing because of the increased importance and interest, it is important to understand the demographic characteristics of the disease.

METHODS

Of 222 patients with a diagnosis of OPLL of the cervical spine, 146 patients were evaluated. Demographic features such as age and sex, and clinical features related to symptoms and treatments, were analyzed, and radiological features observed on plain radiographs, computerized tomography for 3-dimensional reconstruction, and magnetic resonance images were investigated.

RESULTS

Of the 146 subjects, 106 were male patients and 40 were female patients, which showed a male to female ratio of 2.65:1. The mean age of the subjects was 53.3 years. Neurological symptoms such as radiculopathy or myelopathy were observed in 109 patients (74.7%). Diagnosis of OPLL by plain radiography could not be ascertained in 19.9% of the patients. Ossification of paraspinal ligaments also accompanied OPLL in 86.3% of the subjects. Intramedullary high-signal intensity on T2-weighted sagittal plane magnetic resonance images was shown in 62 patients (42.5%). Concurrent herniated intervertebral disc was observed in 37 patients (25.3%).

CONCLUSION

The demographics, clinical presentation, and radiographical findings of OPLL of the cervical spine in Korean patients were analyzed, which could serve as a basis for further study on and treatment of OPLL. The classification method using plain radiographs has some limitation for disease treatment or prognosis. For the exact diagnosis and classification of the OPLL, computerized tomographic scan is more useful.

Ossification of the posterior longitudinal ligament of the cervical spine: etiology and natural history

STUDY DESIGN

Review article.

OBJECTIVE

To review the etiology, natural history, measurement tools, and image diagnosis of ossification of the posterior longitudinal ligament (OPLL) of the cervical spine.

SUMMARY OF BACKGROUND DATA

OPLL is a well-known disease that causes myelopathy. Genetic factors are very important for development of OPLL. However, the pathogenetic gene and natural history of OPLL have not been clarified.

METHODS

The authors reviewed studies about the etiology, natural history, measurement tools, and diagnosis of OPLL, which had been performed by the members of the Investigation Committee on the Ossification of the Spinal Ligaments of the Japanese Ministry of Health, Labour, and Welfare.

RESULTS

The prevalence of OPLL in the general Japanese population was reported to be 1.9% to 4.3% among people older than 30 years. Genetic factors are important for development of OPLL, and some candidate genes have been reported. Clinical course of OPLL has been clarified by a prospective long-term follow-up study. Some radiographic predictors for development of myelopathy were introduced. Image diagnosis of OPLL is easy by plain radiographs, but magnetic resonance imaging and computed tomography are useful to determine cord compression by OPLL.

CONCLUSION

OPLL should be managed on the basis of the consideration of its natural history. Elucidation of pathogenetic genes of OPLL will introduce a new approach for management of OPLL.

Ossification of the posterior longitudinal ligament in the cervical spine: an 11-year comprehensive national epidemiology study

OBJECT

This study aimed to calculate the incidence and prevalence of ossification of the posterior longitudinal ligament (OPLL) in the cervical spine with its comorbid disability.

METHODS

Using an 11-year nationwide database in Taiwan (National Health Insurance Research Database), this retrospective study cohort analyzed the incidences of cervical OPLL causing hospitalization. All patients admitted for the diagnosis of OPLL, regardless of surgery, were identified. Age- and sex-specific incidences, Poisson regression, and multivariate logistic regression analysis were conducted.

RESULTS

Between 1997 and 2007 covering 241,800,725.8 person-years, 1651 patients were admitted for OPLL. The overall incidence of OPLL-related admission was 6.1 per 1 million person-years. Specifically, male sex and older age were associated with higher OPLL incidences (both p < 0.001). Among the 1651 OPLL patients, 542 (32.8%) received conservative management, 612 (37.1%) had anterior only surgery, 353 (21.4%) had posterior only surgery, and 144 (8.7%) had anterior and posterior surgery. Eighty-five patients were moderately to severely disabled (5.2% cumulative incidence rate). The incidences of disability varied by age, in a decreasing trend, except for the 60- to 69-year-old age group (p = 0.05). Patients who received posterior-only surgery were more likely to have disability.

CONCLUSIONS

In a large cohort of the Chinese population, the incidence of cervical OPLL-related admission is 6.1 per 1 million person-years, and the prevalence rate is 7.7 per 100,000 person-years. Higher incidences are observed in elderly and male patients, which implies the disease's degenerative nature. After adjustments for demographics, the incidences and trends of OPLL-related comorbid disability are associated with age and surgical approaches.

Ossification of the posterior longitudinal ligament in a Nigerian woman

Ossification of the posterior longitudinal ligament (OPLL), though commonly reported among the Japanese population, has however been infrequently reported among other racial groups. It has not been reported among black Africans. A case of OPLL of the cervical spine seen in a 62-year-old Nigerian woman is hereby reported.

Laminoplasty outcomes: is there a difference between patients with degenerative stenosis and those with ossification of the posterior longitudinal ligament?

Object

Two common causes of cervical myelopathy include degenerative stenosis and ossification of the posterior longitudinal ligament (OPLL). It has been postulated that patients with OPLL have more complications and worse outcomes than those with degenerative stenosis. The authors sought to compare the surgical results of laminoplasty in the treatment of cervical stenosis with myelopathy due to either degenerative changes or segmental OPLL.

Methods

The authors conducted a retrospective review of 40 instrumented laminoplasty cases performed at a single institution over a 4-year period to treat cervical myelopathy without kyphosis. Twelve of these patients had degenerative cervical stenotic myelopathy ([CSM]; degenerative group), and the remaining 28 had segmental OPLL (OPLL group). The 2 groups had statistically similar demographic characteristics and number of treated levels (mean 3.9 surgically treated levels; p > 0.05). The authors collected perioperative and follow-up data, including radiographic results.

Results

The overall clinical follow-up rate was 88%, and the mean clinical follow-up duration was 16.4 months. The mean radiographic follow-up rate was 83%, and the mean length of radiographic follow-up was 9.3 months. There were no significant differences in the estimated blood loss (EBL) or length of hospital stay (LOS) between the groups (p > 0.05). The mean EBL and LOS for the degenerative group were 206 ml and 3.7 days, respectively. The mean EBL and LOS for the OPLL group were 155 ml and 4 days, respectively. There was a statistically significant improvement of more than one grade in the Nurick score for both groups following surgery (p < 0.05). The Nurick score improvement was not statistically different between the groups (p > 0.05). The visual analog scale (VAS) neck pain scores were similar between groups pre- and postoperatively (p > 0.05). The complication rates were not statistically different between groups either (p > 0.05). Radiographically, both groups lost extension range of motion (ROM) following laminoplasty, but this change was not statistically significant (p > 0.05).

Conclusions

Patients with CSM due to either degenerative disease or segmental OPLL have similar perioperative results and neurological outcomes with laminoplasty. The VAS neck pain scores did not improve significantly with laminoplasty for either group. Laminoplasty may limit extension ROM.

Choice of surgical approach for ossification of the posterior longitudinal ligament in combination with cervical disc hernia

Ossification of the posterior longitudinal ligament (OPLL) is a common spinal disorder that presents with or without cervical myelopathy. Furthermore, there is evidence suggesting that OPLL often coexists with cervical disc hernia (CDH), and that the latter is the more important compression factor. To raise the awareness of CDH in OPLL for spinal surgeons, we performed a retrospective study on 142 patients with radiologically proven OPLL who had received surgery between January 2004 and January 2008 in our hospital. Plain radiograph, three-dimensional computed tomography construction (3D CT), and magnetic resonance imaging (MRI) of the cervical spine were all performed. Twenty-six patients with obvious CDH (15 of segmental-type, nine of mixed-type, two of continuous-type) were selected via clinical and radiographic features, and intraoperative findings. By MRI, the most commonly involved level was C5/6, followed by C3/4, C4/5, and C6/7. The areas of greatest spinal cord compression were at the disc levels because of herniated cervical discs. Eight patients were decompressed via anterior cervical discectomy and fusion (ACDF), 13 patients via anterior cervical corpectomy and fusion (ACCF), and five patients via ACDF combined with posterior laminectomy and fusion. The outcomes were all favorable. In conclusion, surgeons should consider the potential for CDH when performing spinal cord decompression and deciding the surgical approach in patients presenting with OPLL.

Open-door Laminoplasty With Suture Anchor Fixation for Cervical Myelopathy in Ossification of the Posterior Longitudinal Ligament

Expansive laminoplasty was developed to achieve posterior spinal cord decompression while preserving cervical spine stability. In the classic Hirabayashi procedure, the lamina door is tethered open by sutures between the spinous process and facet capsule or paravertebral muscle. The authors present a modified technique, which enhances secure fixation and prevents restenosis owing to hinge closure. Twenty-seven patients (7 females, 20 males) with cervical myelopathy secondary to ossification of the posterior longitudinal ligament were enrolled. Each patient underwent unilateral open-door laminoplasty with suture anchor fixation. Tying and fixation of the sutures onto the holed lateral mass screws was used instead of the conventional method. Radiography, magnetic resonance imaging, and computed tomography scanning were used for imaging studies. The Nurick score was used to assess myelopathy severity, whereas the Japanese Orthopedic Association score was adopted to compare clinical outcome before and after surgery. Mean follow-up period was 38 months (range, 18 to 60). Ten patients had 5 levels of decompression (C3-7), and 17 patients had 4 (C3-6, 12 patients; C4-7, 5 patients). All patients experienced functional improvement of at least 1 Nurick score after surgery. The Japanese Orthopedic Association score increased significantly from 7.5+/-3.2 before surgery to 13.2+/-1.6 at final follow-up. Postoperative radiography and computed tomography scan demonstrated significantly increased sagittal diameter and canal expansion. No neurologic deterioration owing to hinge reclosure or major surgery-related complications were observed. In conclusion, unilateral open-door laminoplasty with suture anchor fixation effectively maintains expansion of the spinal canal and resists closure while preserving alignment and stability. This modified technique has a low complication rate and provides marked functional improvement in patients with cervical myelopathy owing to ossification of the posterior longitudinal ligament.

Expansive laminoplasty for myelopathy in ossification of the longitudinal ligament

Laminectomy, which had long been used for treatment of cervical spondylotic myelopathy, including ossification of the longitudinal ligament in the cervical spine, had numerous complications such as postoperative malalignment of the cervical spine and vulnerability of the spinal cord caused by total removal of the posterior structures. In 1977 Hirabayashi devised an open door expansive laminoplasty, which is a relatively easier and safer procedure than laminectomy, that eliminated such problems by preserving the posterior elements. The decompression effect of the expansive laminoplasty against a compressed spinal cord is comparable with that of laminectomy and anterior decompression followed by fusion, whereas the expansive laminoplasty has no structural problems and adverse effects on adjacent disc levels that often are associated with anterior decompression followed by fusion. Average recovery rate of expansive laminoplasty for cervical spondylotic myelopathy has been reported to be approximately 60% (Japanese Orthopaedic Association score) and with long term stability. At present, authors consider all patients with cervical spondylotic myelopathy candidates for expansive laminoplasty except for those having preoperative kyphosis and single level lesion without canal stenosis. Two remaining problems of expansive laminoplasty to be solved are prevention of C5,C6 radicular pain and/or paresis, the most frequent complication that occurs in approximately 5% to 10% of the patients, although most complications resolve spontaneously within 2 years, and correction of nonlordotic alignment to lordosis which are essential for posterior decompression effect of expansive laminoplasty by allowing the spinal cord to shift dorsally.

Ossification of the posterior longitudinal ligament in three geographically and genetically different populations of ankylosing spondylitis and other spondyloarthropathies

STUDY DESIGN

Cross sectional.

RESEARCH QUESTIONS

(a) Is any clinical variable of ankylosing spondylitis (AS) associated with the presence of ossification of the posterior longitudinal ligament (OPLL)? and (b) Is OPLL present in patients with AS from different geographical or genetic backgrounds?

METHODS

Three groups were assembled: (1) a prospective group of 103 consecutive AS patients from two community based rheumatology clinics from Guadalajara, who were evaluated using: a questionnaire with disease characteristics variables; clinical assessment by a neurologist; lateral radiographic views of the cervical spine and somatosensory evoked potentials (SSEP). (2) Fifty one spondyloarthropathies (SpA) patients from Mexico city whose cervical spine films were retrospectively reviewed. (3) Thirty nine AS patients from Edmonton, Canada whose cervical spine films were retrospectively reviewed and compared with 72 controls.

RESULTS

Group 1: 74% of the 103 patients were men and 86% were HLA-B27 positive. The mean age was 35 years, and mean (SD) disease duration 10 (8) years. OPLL was reported in 16 patients (15.5%; 95% CI 9, 22). OPLL was statistically associated with older age (p = 0.001), longer disease duration (p = 0.001), clinical myelopathy (p = 0.03), worst functional index (p = 0.042), restricted axial movement measurements (all p < 0.001), radiological sacroilitis (p < 0.001 for linear association), osteitis pubis (p = 0.009), hip involvement (p = 0.006 for linear association), and abnormal SSEP (p = 0.008). Group 2: 92% of 51 patients were men; the mean age was 30 years and the mean (SD) disease duration 11 (7) years. OPLL was reported in 15 (29%, 95% CI 17, 41) patients (nine AS, two psoriatic arthritis, three juvenile AS, and one Reiter's syndrome). Group 3: 95% of the 39 patients were men; the mean of age was 46 years and disease duration of 18 (10) years. OPLL was reported in nine (23%; 95% CI 10, 36) patients, including one with psoriatic arthritis, and two with Crohn's disease. OPLL was observed in two of the control group.

CONCLUSIONS

The prevalence of OPLL in AS and SpA is higher than previously recognised and seems to be associated with variables identifying more severe axial disease.

Magnetic resonance imaging findings in ossification of the posterior longitudinal ligament of the cervical spine

OBJECT

Because of the lack of magnetic resonance (MR) signal from cortical bones, MR imaging is inadequate for diagnosing ossified lesions in the spinal canal. However, MR imaging provides important information on spinal cord morphology and associated soft-tissue abnormality. The purpose of this study is to determine the role of MR imaging in the diagnosis and treatment of patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine.

METHODS

The authors reviewed MR imaging findings in 42 patients with cervical OPLL who were examined with a superconducting MR imaging system. The types of OPLL reviewed included eight cases of continuous, 21 cases of segmental, and 13 cases of the mixed type. All patients were treated surgically either by anterior (26 cases) or posterior decompression (16 cases).

CONCLUSIONS

The T1-weighted images clearly demonstrated the spinal cord deformity caused by OPLL. Associated disc protrusion was found to be present at the maximum compression level in 60% of the patients in this series. The highest incidence of disc protrusion (81%) was found in patients with segmental OPLL. Intramedullary hyperintensity on T2*-weighted imaging was noted in 18 patients (43%). The neurological deficits observed in these 18 patients were significantly more severe than those observed in the other 24 patients. Postoperative MR imaging revealed improvement in the spinal cord deformity, although the intramedullary hyperintensity was still observed in most cases. The present study demonstrates the importance of associated disc protrusion in the development of myelopathy in patients with cervical OPLL. Magnetic resonance imaging findings may be used to help determine the actual levels of spinal cord compression and to suggest the method of surgical treatment.

Ossification of the posterior longitudinal ligament of the cervical spine in Asian Indians--a multiracial comparison

Ossification of the Posterior longitudinal ligament (OPLL) has been thought to be a predominantly Japanese disease with few reports among the non-orientals and Caucasians. A prospective clinicoradiological study of 47 symptomatic Caucasoid Indians is reported. Twenty-seven patients presented with myelopathy, twelve with myeloradiculopathy and six with radiculopathy. 'Total' configuration of OPLL was the most frequent (70%). The most frequent location was at C3 and C4 levels. The thickness of OPLL ranged from 2.5 mm to 11.5 mm. Canal stenosis was most severe in patients with 'total' type of OPLL. Ossification of other spinal ligaments were seen in 50% of the patients. Twenty-one patients underwent decompressive laminectomy and twenty of them improved. The difference in the cervical canal diameters and the configuration of OPLL between the Japanese and our population (Caucasoid Indians) may be of therapeutic relevance.

Ossification of the posterior longitudinal ligament mimicking cord compression from a dorsal disc protrusion: a cautionary tale

A patient with focal anterior compression of the dorsal cord at the level of the D6/7 disc was mistakenly diagnosed as a dorsal disc protrusion on the basis of CT myelography. The CT scanning had been confined to axial views at the level of the cord compression. A transthoracic exploration failed to reveal a disc protrusion and the correct diagnosis, ossification of the posterior longitudinal ligament, was only revealed by a subsequent sagittal CT scan. This case emphasizes the dangers of relying on limited axial imaging in diagnosing a spinal lesion.