Acute cervical cord injury associated with ossification of the posterior longitudinal ligament

Effect of Different Types of Ossification of the Posterior Longitudinal Ligament on the Dynamic Biomechanical Response of the Spinal Cord: A Finite Element Analysis

Ossification of the posterior longitudinal ligament (OPLL) has been identified as an important cause of cervical myelopathy. However, the biomechanical mechanism between the OPLL type and the clinical characteristics of myelopathy remains unclear. The aim of this study was to evaluate the effect of different types of OPLL on the dynamic biomechanical response of the spinal cord. A three-dimensional finite element model of the fluid-structure interaction of the cervical spine with spinal cord was established and validated. The spinal cord stress and strain, cervical range of motion (ROM) in different types of OPLL models were predicted during dynamic flexion and extension activity. Different types of OPLL models showed varying degrees of increase in stress and strain under the process of flexion and extension, and there was a surge toward the end of extension. Larger spinal cord stress was observed in segmental OPLL. For continuous and mixed types of OPLL, the adjacent segments of OPLL showed a dramatic increase in ROM, while the ROM of affected segments was limited. As a dynamic factor, flexion and extension of the cervical spine play an amplifying role in OPLL-related myelopathy, while appropriate spine motion is safe and permitted. Segmental OPLL patients are more concerned about the spinal cord injury induced by large stress, and patients with continuous OPLL should be noted to progressive injuries of adjacent level.

Multilevel ossification of the posterior longitudinal ligament causing cervical myelopathy: An observational series of North American patients

Background

Few studies regarding ossification of the posterior longitudinal ligament (OPLL) outside of Asia currently exist in the literature. A set of patients with multilevel cervical OPLL causing symptomatic myelopathy or radiculopathy from a North American sample is analyzed.

Objective

The objective of this study was to describe the demographics, radiographic findings, and surgical outcomes of a cohort of North American patients with degenerative spondylosis presenting for operative management of multilevel (>3 segments) cervical OPLL.

Materials and Methods

Forty-three patients diagnosed with multilevel cervical OPLL and degenerative spondylosis presenting with symptomatic cervical myelopathy or radiculopathy were surgically treated over a 9-year period at a single tertiary care academic medical center. Radiographic measurements were performed on preoperative computed tomography and magnetic resonance imaging images of the cervical spine. Clinical outcomes included pre- and postoperative Nurick scores, 90-day readmission, complication, and revision surgery rates.

Results

The mean age was 66.1 ± 10.9 years with a mean latest follow-up time of 32.7 ± 16.4 months. Most patients had previous diagnoses of obesity (70.7%) and hypertension (55.8%). At least one-quarter of patients were diagnosed with type 2 diabetes (34.9%), hyperlipidemia (41.9%), cardiovascular disease (25.6%), or chronic kidney disease (25.3%). The most common OPLL subtype was segmental (39.5%) and spanned a mean of 3.54 ± 1.48 segments. Myelopathic symptoms were present in 88.4% of patients. All patients experienced significant neurologic improvement at 3-week and latest follow-up (P < 0.001 for both).

Conclusions

Obesity, diabetes, and other metabolic derangements in patients with existing cervical spondylosis may be risk factors for a particularly aggressive form of multilevel OPLL. Various operative approaches may be employed to achieve adequate neurologic recovery. Further workup for OPLL in patients with these risk factors may prove beneficial to ensure appropriate operative management.

Surgery on the Day of Admission Decreases Postoperative Complication Rates for Patients With Central Cord Syndrome: An Analysis of National Surgical Quality Improvement (NSQIP) Data From 2010 to 2020

STUDY DESIGN

Retrospective review.

OBJECTIVE

This study was undertaken to determine what constitutes "early optimal timing" of surgical management of central cord syndrome (CCS) with respect to a reduction of medical complications.

SUMMARY OF BACKGROUND DATA

Data varies on the optimal time for surgical treatment of CCS with some studies favoring early intervention and others advocating that surgery can or should be delayed for 2-6 weeks.

METHODS

This IRB-approved study was a retrospective cross-sectional review of surgical management outcomes for patients diagnosed with CCS using the National Surgical Quality Improvement Program database, which consists of anonymized medical record data from the year 2010 to 2020. Patient data included age, sex, American Society of Anesthesiologists score, current procedural terminology codes, length of stay, and postoperative complications. Patients were grouped into admission-day surgery, next-day surgery, and late-surgery groups.

RESULTS

A total of 738 patients who underwent surgery to treat CCS were identified in the National Surgical Quality Improvement Program database from 2010 to 2020 and included in this study. Admission-day surgery compared with next-day surgery was associated with a decreased postoperative complication rate after multivariate analysis (odds ratio: 0.52; 95% CI: 0.28-0.97; P =0.0387) as well as shorter length of stay ( P <0.0001). Complication rates between the next-day-surgery cohort and late-surgery cohort did not differ after multivariate analysis (odds ratio: 1.02; 95% CI: 0.63-1.65; P =0.9451), but the length of stay was shorter for next-day surgery ( P <0.0001). Two-year rolling averages for the admission-day-surgery rate and next-day-surgery rate show a compound annual growth rate of 2.52% and 4.10%, respectively.

CONCLUSIONS

In patients admitted for surgical treatment of CCS, those who receive admission-day surgery have significantly reduced 30-day complication rates as well as shorter length of stays. Therefore, we advocate that "early surgery" should be defined as surgery on the day of admission and should occur in as timely a manner as possible. Prior studies, which define "early surgery" as within 24 hours might, unfortunately, fall short of reaching the optimal threshold for the reduction of 30-day medical complications associated with the treatment of patients with CCS.

Effects of cervical rotatory manipulation on the cervical spinal cord complex with ossification of the posterior longitudinal ligament in the vertebral canal: A finite element study

Background: There are few studies focusing on biomechanism of spinal cord injury according to the ossification of the posterior longitudinal ligament (OPLL) during cervical rotatory manipulation (CRM). This study aimed to explore the biomechanical effects of CRM on the spinal cord, dura matter and nerve roots with OPLL in the cervical vertebral canal. Methods: Three validated FE models of the craniocervical spine and spinal cord complex were constructed by adding mild, moderate, and severe OPLL to the healthy FE model, respectively. We simulated the static compression of the spinal cord by OPLL and the dynamic compression during CRM in the flexion position. The stress distribution of the spinal cord complex was investigated. Results: The cervical spinal cord experienced higher von Mises stress under static compression by the severe OPLL. A higher von Mises stress was observed on the spinal cord in the moderate and severe OPLL models during CRM. The dura matter and nerve roots had a higher von Mises stress in all three models during CRM. Conclusion: The results show a high risk in performing CRM in the flexion position on patients with OPLL, in that different occupying ratios in the vertebral canal due to OPLL could significantly increase the stress on the spinal cord complex.

Detecting ossification of the posterior longitudinal ligament on plain radiographs using a deep convolutional neural network: a pilot study

BACKGROUND CONTEXT

Its rare prevalence and subtle radiological changes often lead to difficulties in diagnosing cervical ossification of the posterior longitudinal ligament (OPLL) on plain radiographs. However, OPLL progression may lead to trauma-induced spinal cord injury, resulting in severe paralysis. To address the difficulties in diagnosis, a deep learning approach using a convolutional neural network (CNN) was applied.

PURPOSE

The aim of our research was to evaluate the performance of a CNN model for diagnosing cervical OPLL.

STUDY DESIGN AND SETTING

Diagnostic image study.

PATIENT SAMPLE

This study included 50 patients with cervical OPLL, and 50 control patients with plain radiographs.

OUTCOME MEASURES

For the CNN model performance evaluation, we calculated the area under the receiver operating characteristic curve (AUC). We also compared the sensitivity, specificity, and accuracy of the diagnosis by the CNN with those of general orthopedic surgeons and spine specialists.

METHODS

Computed tomography was used as the gold standard for diagnosis. Radiographs of the cervical spine in neutral, flexion, and extension positions were used for training and validation of the CNN model. We used the deep learning PyTorch framework to construct the CNN architecture.

RESULTS

The accuracy of the CNN model was 90% (18/20), with a sensitivity and specificity of 80% and 100%, respectively. In contrast, the mean accuracy of orthopedic surgeons was 70%, with a sensitivity and specificity of 73% (SD: 0.12) and 67% (SD: 0.17), respectively. The mean accuracy of the spine surgeons was 75%, with a sensitivity and specificity of 80% (SD: 0.08) and 70% (SD: 0.08), respectively. The AUC of the CNN model based on the radiographs was 0.924.

CONCLUSIONS

The CNN model had successful diagnostic accuracy and sufficient specificity in the diagnosis of OPLL.

Hao1 Is Not a Pathogenic Factor for Ectopic Ossifications but Functions to Regulate the TCA Cycle In Vivo

Ossification of the posterior longitudinal ligament (OPLL), a disease characterized by the ectopic ossification of a spinal ligament, promotes neurological disorders associated with spinal canal stenosis. While blocking ectopic ossification is mandatory to prevent OPLL development and progression, the mechanisms underlying the condition remain unknown. Here we show that expression of hydroxyacid oxidase 1 (Hao1), a gene identified in a previous genome-wide association study (GWAS) as an OPLL-associated candidate gene, specifically and significantly decreased in fibroblasts during osteoblast differentiation. We then newly established Hao1-deficient mice by generating Hao1-flox mice and crossing them with CAG-Cre mice to yield global Hao1-knockout (CAG-Cre/Hao1flox/flox; Hao1 KO) animals. Hao1 KO mice were born normally and exhibited no obvious phenotypes, including growth retardation. Moreover, Hao1 KO mice did not exhibit ectopic ossification or calcification. However, urinary levels of some metabolites of the tricarboxylic acid (TCA) cycle were significantly lower in Hao1 KO compared to control mice based on comprehensive metabolomic analysis. Our data indicate that Hao1 loss does not promote ectopic ossification, but rather that Hao1 functions to regulate the TCA cycle in vivo.

Pros and Cons of Early and Very Early Surgery for Traumatic Central Cord Syndrome with Spinal Stenosis: Literature Review and Case Report

BACKGROUND

 The case of a 69-year-old patient with an acute traumatic central cord syndrome (ATCCS) with preexisting spinal stenosis raised a discussion over the question of conservative versus surgical treatment in the acute setting. We provide a literature overview on the management (conservative vs. surgical treatment) of ATCCS with preexisting spinal stenosis.

METHODS

 We reviewed the literature concerning essential concepts for the management of ATCCS with spinal stenosis and cervical spinal cord injury. The data retrieved from these studies were applied to the potential management of an illustrative case report.

RESULTS

 Not rarely has ATCCS an unpredictable neurologic course because of its dynamic character with secondary injury mechanisms within the cervical spinal cord in the early phase, the possibility of functional deterioration, and the appearance of a neuropathic pain syndrome during late follow-up. The result of the literature review favors early surgical treatment in ATCCS patients with preexisting cervical stenosis.

CONCLUSION

 Reluctance toward aggressive and timely surgical treatment of ATCCS should at least be questioned in patients with preexisting spinal stenosis.

The Role of Magnetic Resonance Imaging to Inform Clinical Decision-Making in Acute Spinal Cord Injury: A Systematic Review and Meta-Analysis

The clinical indications and added value of obtaining MRI in the acute phase of spinal cord injury (SCI) remain controversial. This review aims to critically evaluate evidence regarding the role of MRI to influence decision-making and outcomes in acute SCI. A systematic review and meta-analysis were performed according to PRISMA methodology to identify studies that address six key questions (KQs) regarding diagnostic accuracy, frequency of abnormal findings, frequency of altered decision-making, optimal timing, and differences in outcomes related to obtaining an MRI in acute SCI. A total of 32 studies were identified that addressed one or more KQs. MRI showed no adverse events in 156 patients (five studies) and frequently identified cord compression (70%, 12 studies), disc herniation (43%, 16 studies), ligamentous injury (39%, 13 studies), and epidural hematoma (10%, two studies), with good diagnostic accuracy (seven comparative studies) except for fracture detection. MRI findings often altered management, including timing of surgery (78%, three studies), decision to operate (36%, 15 studies), and surgical approach (29%, nine studies). MRI may also be useful to determine the need for instrumentation (100%, one study), which levels to decompress (100%, one study), and if reoperation is needed (34%, two studies). The available literature consistently concluded that MRI was useful prior to surgical treatment (13 studies) and after surgery to assess decompression (two studies), but utility before/after closed reduction of cervical dislocations was unclear (three studies). One study showed improved outcomes with an MRI-based protocol but had a high risk of bias. Heterogeneity was high for most findings (I² > 0.75). MRI is safe and frequently identifies findings alter clinical management in acute SCI, although direct evidence of its impact on outcomes is lacking. MRI should be performed before and after surgery, when feasible, to facilitate improved clinical decision-making. However, further research is needed to determine its optimal timing, effect on outcomes, cost-effectiveness, and utility before and after closed reduction.

Spinal Cord Signal Change on Magnetic Resonance Imaging May Predict Worse Clinical In- and Outpatient Outcomes in Patients with Spinal Cord Injury: A Prospective Multicenter Study in 459 Patients

Prognostic factors for clinical outcome after spinal cord (SC) injury (SCI) are limited but important in patient management and education. There is a lack of evidence regarding magnetic resonance imaging (MRI) and clinical outcomes in SCI patients. Therefore, we aimed to investigate whether baseline MRI features predicted the clinical course of the disease. This study is an ancillary to the prospective North American Clinical Trials Network (NACTN) registry. Patients were enrolled from 2005-2017. MRI within 72 h of injury and a minimum follow-up of one year were available for 459 patients. Patients with American Spinal Injury Association impairment scale (AIS) E were excluded. Patients were grouped into those with (n = 354) versus without (n = 105) SC signal change on MRI T2-weighted images. Logistic regression analysis adjusted for commonly known a priori confounders (age and baseline AIS). Main outcomes and measures: The primary outcome was any adverse event. Secondary outcomes were AIS at the baseline and final follow-up, length of hospital stay (LOS), and mortality. A regression model adjusted for age and baseline AIS. Patients with intrinsic SC signal change were younger (46.0 (interquartile range (IQR) 29.0 vs. 50.0 (IQR 20.5) years, p = 0.039). There were no significant differences in the other baseline variables, gender, body mass index, comorbidities, and injury location. There were more adverse events in patients with SC signal change (230 (65.0%) vs. 47 (44.8%), p < 0.001; odds ratio (OR) = 2.09 (95% confidence interval (CI) 1.31-3.35), p = 0.002). The most common adverse event was cardiopulmonary (186 (40.5%)). Patients were less likely to be in the AIS D category with SC signal change at baseline (OR = 0.45 (95% CI 0.28-0.72), p = 0.001) and in the AIS D or E category at the final follow-up (OR = 0.36 (95% CI 0.16-0.82), p = 0.015). The length of stay was longer in patients with SC signal change (13.0 (IQR 17.0) vs. 11.0 (IQR 14.0), p = 0.049). There was no difference between the groups in mortality (11 (3.2%) vs. 4 (3.9%)). MRI SC signal change may predict adverse events and overall LOS in the SCI population. If present, patients are more likely to have a worse baseline clinical presentation (i.e., AIS) and in- or outpatient clinical outcome after one year. Patients with SC signal change may benefit from earlier, more aggressive treatment strategies and need to be educated about an unfavorable prognosis.

Does surgical treatment increase the progression of spinal cord injury in patients with ossification of posterior longitudinal ligament of cervical spine? A systematic review and meta-analysis

PURPOSE

The purpose of this study is to explore if the surgical treatment will accelerate the progression of spinal cord injury (SCI) in patients with cervical Ossification of the posterior longitudinal ligament (OPLL) and if surgery will have better curative effect than conservative treatment.

METHODS

An extensive search of literature was implemented in PubMed, EMBASE, and other online databases. The quality of the included articles was evaluated according to the Newcastle-Ottawa Quality Assessment Scale, as recommended by the Cochrane manual, and meta-analysis was performed using the review manage5.3 software.

RESULTS

No obvious statistical difference was observed in the rate of SCI progression (P > 0.05, OR 1.15 [0.66, 2.00]), cervical range of motion, (P > 0.05, weighted mean difference (WMD) 4.52 [-5.75, 14.79]), and Japanese Orthopedic Association scores before surgery (P > 0.05, WMD -2.78 [-7.87, 2.32]) between the surgical group and conservative treatment group. However the surgical group illustrated obviously higher neurofunctional recovery rate (P < 0.05, OR 6.07 [1.55, 23.78]) and postoperative JOA score of the surgery group (P < 0.05, WMD -0.77 [-1.21, -0.33]) than conservative group.

CONCLUSIONS

Based on this meta-analysis, there is not enough evidence to indicate that surgery will accelerate the progress of SCI with OPLL. However, the superiority of surgical efficacy can be observed over conservative treatment in terms of relieving neurological symptoms.

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.

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

OBJECTIVE

We sought to evaluate the influence of trauma-induced spinal cord injury (SCI) on the operative management of cervical ossification of the posterior longitudinal ligament (OPLL) in a North American cohort.

METHODS

A retrospective chart review was performed for all patients who underwent surgical management for OPLL in an academic medical center between November 2006 and July 2019. Patients were categorized into 1 of 2 groups and compared on the basis of their initial presentation: 1) SCI with OPLL or 2) cervical myelopathy (CM) with OPLL. Patient characteristics were collected. OPLL classification and K-line measurements were performed. Surgical approach, levels fused/decompressed, blood loss, postoperative length of stay, surgical complications, and neurologic outcome were recorded.

RESULTS

Among the 28-patient cohort, 12 were in the SCI with OPLL group and 16 were in the CM with OPLL group. The most common type of OPLL in both groups was segmental (n = 21, 75%). The average levels fused/decompressed (P = 0.0176), estimated blood loss (P = 0.0204), and postoperative length of stay (P = 0.0003) were all significantly higher in the SCI with OPLL group. There were significantly more anterior-only surgical approaches performed in the CM with OPLL group (P = 0.0159). The motor score at admission (P = 0.0005) and at latest follow-up (P = 0.0003) for the SCI with OPLL group was significantly lower than the CM with OPLL group.

CONCLUSIONS

Patients with SCI complicated by OPLL had worse preoperative and postoperative neurologic motor scores as compared with patients in the CM with OPLL group. Most of the patients in our cohort showed neurologic improvement.

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%).

Biomechanical Effects on Cervical Spinal Cord and Nerve Root Following Laminoplasty for Ossification of the Posterior Longitudinal Ligament in the Cervical Spine: A Comparison Between Open-Door and Double-Door Laminoplasty Using Finite Element Analysis

Many clinical case series have reported the predisposing factors for C5 palsy and have presented comparisons of the two types of laminoplasty. However, there have been no biomechanical studies focusing on cervical spinal cord and nerve root following laminoplasty. The purpose of this study is to investigate biomechanical changes in the spinal cord and nerve roots following the two most common types of laminoplasty, open-door and double-door laminoplasty, for cervical ossification of the posterior longitudinal ligament (OPLL). A finite element (FE) model of the cervical spine and spinal cord with nerve root complex structures was developed. Stress changes in the spinal cord and nerve roots, posterior shift of the spinal cord, and displacement of the cervical nerve roots were analyzed with two types of cervical laminoplasty models for variations in the degree of canal occupying ratio and shape of the OPLL. The shape and degree of spinal cord compression caused by the OPLL had more influence on the changes in stress, posterior shift of the spinal cord, and displacement of the nerve root than the type of laminoplasty. The lateral-type OPLL resulted in imbalanced stress on the nerve roots and the highest nerve root displacement. Type of laminoplasty and shape and degree of spinal cord compression caused by OPLL were found to influence the changes in stress and posterior displacement of the cervical spinal cord and nerve roots. Lateral-type OPLL might contribute to the development of C5 palsy due to the imbalanced stress and tension on the nerve roots after laminoplasty.

Molecular Pathophysiology of Ossification of the Posterior Longitudinal Ligament (OPLL)

Ossification of the posterior longitudinal ligament (OPLL) can be defined as an ectopic ossification in the tissues of spinal ligament showing a hyperostotic condition. OPLL is developed mostly in the cervical spine and clinical presentations of OPLL are majorly myelopathy and/or radiculopathy, with serious neurological pathology resulting in paralysis of extremities and disturbances of motility lowering the quality of life. OPLL is known to be an idiopathic and multifactorial disease, which genetic factors and non-genetic factors including diet, obesity, physical strain on the posterior longitudinal ligament, age, and diabetes mellitus, are involved into the pathogenesis. Up to now, surgical management by decompressing the spinal cord is regarded as standard treatment for OPLL, although there might be the risk of development of reprogression of ossification. The molecular pathogenesis and efficient therapeutic strategy, especially pharmacotherapy and/or preventive intervention, of OPLL has not been clearly elucidated and suggested. Therefore, in this review, we tried to give an overview to the present research results on OPLL, in order to shed light on the potential pharmacotherapy based on molecular pathophysiologic aspect of OPLL, especially on the genetic/genomic factors involved into the etiology of OPLL.

A Systematic Review of Classification Systems for Cervical Ossification of the Posterior Longitudinal Ligament

DESIGN

Systematic review.

OBJECTIVE

To conduct a systematic review to (1) summarize various classification systems used to describe cervical ossification of the posterior longitudinal ligament (OPLL) and (2) evaluate the diagnostic accuracy of various imaging modalities and the reliability of these classification systems.

METHODS

A search was performed to identify studies that used a classification system to categorize patients with OPLL. Furthermore, studies were included if they reported the diagnostic accuracy of various imaging modalities or the reliability of a classification system.

RESULTS

A total of 167 studies were deemed relevant. Five classification systems were developed based on X-ray: the 9-classification system (0.60%); continuous, segmental, mixed, localized or focal, circumscribed and others (92.81%); hook, staple, bridge, and total types (2.40%); distribution of OPLL (2.40%); and K-line classification (4.19%). Six methods were based on computed tomography scans: free-type, contiguous-type, and broken sign (0.60%); hill-, plateau-, square-, mushroom-, irregular-, or round-shaped (5.99%); rectangular, oval, triangular, or pedunculate (1.20%); centralized or laterally deviated (1.80%); plank-, spindle-, or rod-shaped (0.60%); and rule of nine (0.60%). Classification systems based on 3-dimensional computed tomography were bridging and nonbridging (1.20%) and flat, irregular, and localized (0.60%). A single classification system was based on magnetic resonance imaging: triangular, teardrop, or boomerang. Finally, a variation of methods was used to classify OPLL associated with the dura mater (4.19%).

CONCLUSIONS

The most common method of classification was that proposed by the Japanese Ministry of Health, Labour and Welfare. Other important methods include K-line (+/-), signs of dural ossification, and patterns of distribution.

Ossification of the Posterior Longitudinal Ligament in Cervical Spine: Prevalence, Management, and Prognosis

Ossification of the posterior longitudinal ligament (OPLL) in the cervical spine and related neurological complications are not uncommon in East Asian countries. The estimated prevalence of cervical OPLL-related hospitalization is 7.7 per 100,000 person-years in Taiwan, and higher incidence rates have been observed in elderly and male patients. Although cervical OPLL is frequently insidious, it can eventually cause myelopathy and predispose patients to spinal cord injury (SCI). There are multiple options for managing cervical OPLL, ranging from observation to many kinds of surgical procedures, including posterior laminoplasty, laminectomy with or without fusion, anterior corpectomy with or without instrumentation, and circumferential decompression and fusion. None of these surgical approaches is free of complications. However, to date, there is still a lack of consensus regarding the choice of the surgical approach and the timing of surgical intervention. Cervical SCI and related neurological disabilities are more likely to occur in OPLL patients, who should therefore be cautioned regarding the possibility of a subsequent SCI if treated without surgery. This article aimed to review the prevalence, management strategies, and prognosis of cervical OPLL.

Risk Factors and Prognosis for Acute Progression of Myelopathic Symptoms in Patients Ossification of the Posterior Longitudinal Ligament After Minor Trauma

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

The aim of this study was to identify the risk factors for acute progression of myelopathic symptoms (PMS) associated with ossification of the posterior longitudinal ligament (OPLL) after minor trauma and to compare the prognosis between an acute PMS group and a chronic PMS group.

SUMMARY OF BACKGROUND DATA

Although the prevalence of OPLL among patients with cervical myelopathy is high, few studies have been published regarding the risk factors for acute PMS associated with OPLL after minor trauma.

METHODS

Patients with OPLL who had histories of minor trauma and had undergone surgery were divided according to clinical course into an acute (within 48 hours, n = 38) and a chronic PMS group (n = 32). The type of trauma and the clinical and radiologic characteristics were compared. The clinical outcomes were also compared at admission and at 1 and 2 years postoperatively.

RESULTS

The types of trauma were significantly different between the two groups (P < 0.05). Univariate analysis revealed that older age, a narrower space available for the cord, and a higher rate of stenosis in the spinal canal were associated with acute PMS after minor trauma (P = 0.014, 0.020, and 0.006, respectively). However, the rate of stenosis in the spinal canal was the only risk factor that was identified in a multivariate analysis (P = 0.023; odds ratio, 0.872; 95% confidence interval, 0.774-0.982). The Japanese Orthopedic Association scores at the initial visit and at postoperative years 1 and 2 were significantly lower in the acute PMS group than in the chronic PMS group (P < 0.001, P < 0.001, and P < 0.001, respectively).

CONCLUSION

One risk factor for acute PMS in patients with OPLL after minor trauma is a higher rate of stenosis of the spinal canal. Patients with acute PMS exhibited unfavorable neurologic outcomes. Preventive surgical treatment may be recommended for patients with significant OPLL with mild cervical myelopathy.

LEVEL OF EVIDENCE

3.

Spinal Cord Injury-What Are the Controversies?

Traumatic spinal cord injuries have a tremendous impact on individuals, families, and society as a whole. Substantial heterogeneity in the patient population, their presentation and underlying pathophysiology has sparked debates along the care spectrum from initial assessment to definitive treatment. This article reviews spinal cord injury (SCI) management followed by a discussion of the salient controversies in the field. Current care practices modeled on the American Association of Neurological Surgeons/Congress of Neurological Surgeons joint section guidelines are highlighted including key recommendations regarding immobilization, avoidance of hypotension, early International Standards for Neurological Classification of SCI examination and intensive care unit treatment. From a diagnostic perspective, the evolving roles of CT, MRI, and leading-edge microstructural MRI techniques are discussed with descriptions of the relevant clinical literature for each. Controversies in management relevant to clinicians including the timing of surgical decompression, methylprednisolone administration, blood pressure augmentation, intraoperative electrophysiological monitoring, and the role of surgery in central cord syndrome and pediatric SCI are also covered in detail. Finally, the article concludes with a reflection on clinical trial design tailored to the heterogeneous population of individuals with SCI.

Cervical vertebral injuries associated with the ossification of the posterior longitudinal ligament: Imaging features

Background

Spinal injuries associated with ossification of the posterior longitudinal ligament (OPLL) have been characterized. However, the imaging features of traumatic cervical spine fractures in patients with OPLL have not been assessed adequately.

Purpose

To characterize the patterns of traumatic cervical spine fractures associated with different types of OPLL.

Material and Methods

We retrospectively analyzed the patterns of fractures resulting from cervical spine injury in patients with OPLL of different types and assessed the fracture patterns in patients with ankylosed segments.

Results

Twenty-six patients (23 men, 3 women; median age, 67.0 years; age range, 43–87 years) were included. Fall from a height <3 m was the most common trauma. Contiguous type OPLL was seen in 11 patients (42%), segmental type in 11 (42%), and mixed type in four (15%). Four of the contiguous OPLL and one of the mixed OPLL patients had ankylosed segments. The incidence of cervical fractures was 69% (16/26): seven (64%) in contiguous OPLL, five (46%) in segmental OPLL, and in all four patients with mixed OPLL. Unilateral interfacetal fracture-dislocation was most common (4/16); the others were bilateral interfacetal fracture-dislocation, fractures through the ankylosed segment, transdiscal fractures, isolated facet fractures, and compression fractures. Cervical fractures were exclusively observed in the C4 to C7, except in one case occurred at the C2 level.

Conclusion

Interfacetal fracture-dislocation in the lower cervical vertebrae constitutes the most common injury resulting from minor trauma.

A model of acute central cervical spinal cord injury syndrome combined with chronic injury in goats

PURPOSE

To develop a large animal model for acute central cervical spinal cord injury syndrome (ACCSCIS.

METHODS

Twenty-four adult male goats were randomized into four groups including group A with acute compression injury, group B with anterior chronic compression, group C as the test group that received anterior chronic compression by screw and acute compression by posterior balloon insertion, and group D as normal controls that received sham surgery. Neurological function (modified Tarlov motor function), CT, MRI, cortical somatosensory evoked potentials (CSEP), and pathological analysis were evaluated. The data were analyzed statistically.

RESULTS

The motor function of the goats in group C was significantly lower than other groups. CSEP before spinal cord compression showed a stable pattern. Spinal cord compression resulted in a gradual decrement in the peak latency and significant increment in the peak amplitude. Cervical spinal canal occupying ratio was significantly lower in group C than the other groups. MRI revealed focal low signal in T1 weighted images and focal high signal in T2 weighted images in group C. Pathological analysis showed more severe lesions in the gray matter than that in the white matter in group C.

CONCLUSIONS

The model well simulated the pathogenesis and resembled the clinical characteristics of ACCSCIS. This model seems to have the potential to contribute to the development of effective therapies for ACCSCIS.

Effect of posterior decompression extent on biomechanical parameters of the spinal cord in cervical ossification of the posterior longitudinal ligament

Ossification of the posterior longitudinal ligament is a common cause of the cervical myelopathy due to compression of the spinal cord. Patients with ossification of the posterior longitudinal ligament usually require the decompression surgery, and there is a need to better understand the optimal surgical extent with which sufficient decompression without excessive posterior shifting can be achieved. However, few quantitative studies have clarified this optimal extent for decompression of cervical ossification of the posterior longitudinal ligament. We used finite element modeling of the cervical spine and spinal cord to investigate the effect of posterior decompression extent for continuous-type cervical ossification of the posterior longitudinal ligament on changes in stress, strain, and posterior shifting that occur with three different surgical methods (laminectomy, laminoplasty, and hemilaminectomy). As posterior decompression extended, stress and strain in the spinal cord decreased and posterior shifting of the cord increased. The location of the decompression extent also influenced shifting. Laminectomy and laminoplasty were very similar in terms of decompression results, and both were superior to hemilaminectomy in all parameters tested. Decompression to the extents of C3-C6 and C3-C7 of laminectomy and laminoplasty could be considered sufficient with respect to decompression itself. Our findings provide fundamental information regarding the treatment of cervical ossification of the posterior longitudinal ligament and can be applied to patient-specific surgical planning.

Ossification of the Posterior Longitudinal Ligament: Etiology, Diagnosis, and Outcomes of Nonoperative and Operative Management

Study Design Narrative review. Objective To provide an overview on the diagnosis, natural history, and nonoperative and operative management of ossification of the posterior longitudinal ligament (OPLL). OPLL is a multifactorial condition caused by ectopic hyperostosis and calcification of the posterior longitudinal ligament. Familial inheritance and genetic factors have been implicated in the etiology of OPLL. The cervical spine is most commonly affected followed by the thoracic spine. The clinical manifestations range from asymptomatic to myelopathy or myeloradiculopathy. Methods Using PubMed, studies published prior to October 2014 with the keywords "OPLL, etiology"; "OPLL, genetics"; "OPLL, spinal cord injury"; "OPLL, natural history"; "OPLL, non-surgical management"; OPLL, surgical management"; "OPLL, surgical complications" were evaluated. Results The review addresses the etiology, epidemiology, classification, clinical presentation, imaging findings, and nonoperative and operative management of OPLL. Complications associated with surgical management of OPLL are also discussed. Conclusions OPLL commonly presents with myelopathy and radiculopathy. Spine providers should consider OPLL in their differential diagnosis and when reviewing images. If surgical intervention is pursued, imaging-based measurements and findings can help in choosing an anterior versus posterior surgical approach.

Influence of sagittal and axial types of ossification of posterior longitudinal ligament on mechanical stress in cervical spinal cord: A finite element analysis

BACKGROUND

There are few studies focusing on the prediction of stress distribution according to the types of ossification of the posterior longitudinal ligament, which can be fundamental information associated with clinical aspects such as the relationship between stress level and neurological symptom severity. In this study, the influence of sagittal and axial types of ossification of the posterior longitudinal ligament on mechanical stress in the cervical spinal cord was investigated.

METHODS

A three-dimensional finite element model of the cervical spine with spinal cord was developed and validated. The von Mises stresses in the cord and the reduction in cross-sectional areas and volume of the cord were investigated for various axial and sagittal types according to the occupying ratio of ossification of the posterior longitudinal ligament in the spinal canal.

FINDINGS

The influence of axial type was less than that of the sagittal type, even though the central type showed higher maximum stresses in the cord, especially for the continuous type. With a 60% occupying ratio of ossification of the posterior longitudinal ligament, the maximum stress was significantly high and the cross-sectional area of the spinal cord was reduced by more than 30% of the intact area regardless of sagittal or axial types. Finally, a higher level of sagittal extension would increase the peak cord tissue stress, which would be related to the neurological dysfunction and tissue damage.

INTERPRETATION

Quantitative investigation of biomechanical characteristics such as mechanical stress may provide fundamental information for pre-operative planning of treatment for ossification of the posterior longitudinal ligament.

Laminoplasty versus conservative treatment for acute cervical spinal cord injury caused by ossification of the posterior longitudinal ligament after minor trauma

BACKGROUND CONTEXT

No reports to date have accurately evaluated the management for acute spinal cord injury (SCI) caused by ossification of the posterior longitudinal ligament (OPLL) after minor trauma.

PURPOSE

To assess whether outcomes of laminoplasty is better than conservative treatment.

STUDY DESIGN/SETTING

A retrospective study.

PATIENT SAMPLE

Thirty-one patients underwent surgery (L group) and 29 patients underwent conservative treatment (C group).

OUTCOME MEASURES

Disability, muscle strength, sensation, and general health status.

METHODS

Patients were managed according to routine clinical practice and the results between groups were compared. Clinical and radiographic outcomes were assessed at admission, discharge, 6 months and at the final visit. Causes for trauma, duration of hospital stay, and complication were also evaluated.

RESULTS

Causes for trauma included falling, traffic accidents and sports. Mixed and segmental types were the most frequent cause of OPLL resulting into SCI. Duration of hospital stay and complications were less in the L group. Motor and sensory scores increased in the L group at discharge (p<.05) and at 6 months (p<.05), and maintained thereafter (p>.05); scores improved significantly in the C group at 6 months (p<.05), with a slight deterioration with time (p>.05); scores in the L group were higher than in the C group at each time point after surgery (p<.05). Bodily pain and mental health in SF-36 improved at discharge in the L group (p<.05); all scores improved at 6 months in both the groups (p<.05), with better improvements in the L group (p<.05). The canal diameter increased and occupation ratio decreased in the L group (p<.05), and maintained thereafter (p<.05); a slight increase of occupation ratio was observed in the C group (p>.05). Lordotic angle and range of motion were maintained in both the groups, with no significance between groups (p>.05). High-signal intensity decreased at 6 months (p<.05) in the L group; no significant change was found in the C group during the follow-up (p>.05); Significant difference was detected between the groups at 6 months and at the final visit (p<.05).

CONCLUSIONS

Most of the OPLL patients displayed as incomplete SCI after minor trauma. Although spontaneous improvement of SCI without surgery is often observed, laminoplasty has more satisfactory outcomes, prevents late compression of cord, and reduces perioperative complications, although with no significant benefit in cervical alignment and range of motion.

Ossification of the posterior longitudinal ligament related genes identification using microarray gene expression profiling and bioinformatics analysis

Ossification of the posterior longitudinal ligament (OPLL) is a kind of disease with physical barriers and neurological disorders. The objective of this study was to explore the differentially expressed genes (DEGs) in OPLL patient ligament cells and identify the target sites for the prevention and treatment of OPLL in clinic. Gene expression data GSE5464 was downloaded from Gene Expression Omnibus; then DEGs were screened by limma package in R language, and changed functions and pathways of OPLL cells compared to normal cells were identified by DAVID (The Database for Annotation, Visualization and Integrated Discovery); finally, an interaction network of DEGs was constructed by string. A total of 1536 DEGs were screened, with 31 down-regulated and 1505 up-regulated genes. Response to wounding function and Toll-like receptor signaling pathway may involve in the development of OPLL. Genes, such as PDGFB, PRDX2 may involve in OPLL through response to wounding function. Toll-like receptor signaling pathway enriched genes such as TLR1, TLR5, and TLR7 may involve in spine cord injury in OPLL. PIK3R1 was the hub gene in the network of DEGs with the highest degree; INSR was one of the most closely related genes of it. OPLL related genes screened by microarray gene expression profiling and bioinformatics analysis may be helpful for elucidating the mechanism of OPLL.

Evidence-based management of central cord syndrome

Object

Evidence-based medicine is used to examine the current treatment options, timing of surgical intervention, and prognostic factors in the management of patients with traumatic central cord syndrome (TCCS).

Methods

A computerized literature search of the National Library of Medicine database, Cochrane database, and Google Scholar was performed for published material between January 1966 and February 2013 using key words and Medical Subject Headings. Abstracts were reviewed and selected, with the articles segregated into 3 main categories: surgical versus conservative management, timing of surgery, and prognostic factors. Evidentiary tables were then assembled, summarizing data and quality of evidence (Classes I–III) for papers included in this review.

Results

The authors compiled 3 evidentiary tables summarizing 16 studies, all of which were retrospective in design. Regarding surgical intervention versus conservative management, there was Class III evidence to support the superiority of surgery for patients presenting with TCCS. In regards to timing of surgery, most Class III evidence demonstrated no difference in early versus late surgical management. Most Class III studies agreed that older age, especially age greater than 60–70 years, correlated with worse outcomes.

Conclusions

No Class I or Class II evidence was available to determine the efficacy of surgery, timing of surgical intervention, or prognostic factors in patients managed for TCCS. Hence, there is a need to perform well-controlled prospective studies and randomized controlled clinical trials to further investigate the optimal management (surgical vs conservative) and timing of surgical intervention in patients suffering from TCCS.

Significance of segmental instability in cervical ossification of the posterior longitudinal ligament and treated by a posterior hybrid technique

STUDY DESIGN

Retrospective cohort case study.

OBJECTIVE

To evaluate significance of segmental instability (SI) in cervical ossification of the posterior longitudinal ligament (OPLL) myelopathy and effectiveness of a posterior hybrid technique in the treatment of OPLL associated with SI. Some studies suggested both static and dynamic compression factors accounted for the pathogenesis of myelopathy in the OPLL patients.

METHOD

Between May 2005 and August 2007, 15 patients with multilevel cervical OPLL, diagnosed to be associated with SI, were treated by a posterior hybrid technique including laminoplasty and fusion at instable levels with lateral mass screw fixation. Another 15 cohort patients without SI treated by laminoplasty in the same period were included in the control group. Radiological and clinical data were compared between two groups.

RESULTS

There were no significant differences in Preop. lordotic angle, extent of OPLL, type of OPLL and occupying rate, but more patients tended to present high-intensity zone (HIZ) on MRI in the group with SI. In 15 patients with SI, 17 intervertebral levels had SI, which were distributed at the noncontinuous levels of mixed-type OPLL or the adjacent levels of continuous-type OPLL. They were also consistent with the presence of HIZ levels in the major of patients. After operation, the lordotic angle was maintained well by the posterior hybrid technique in the OPLL with SI group, and was significantly greater than that in the OPLL without SI at the 3- and 4-year follow-up point. Postoperative kyphotic change of the cervical spine and postoperative progression of the ossified lesion were not observed in the OPLL with SI group, but they were respectively observed in four cases (26.7 %) and two cases (13.3 %) in the OPLL without SI group at the 4-year follow-up point. The preoperative C-JOA score in the OPLL with SI group was lower than that in the OPLL without SI group. The average C-JOA score and improvement rate were comparable in the first 2 years after operation between two groups, but there was a decrease in C-JOA score and improvement rate in the following 2 years in the OPLL without SI group. At the 3- and 4-year follow-up points, both postoperative C-JOA score improvement rate in the OPLL with SI group were superior to those in the OPLL without SI group. Each group had one case developing C5 palsy, but three cases in the OPLL without SI group developed late neurological deterioration due to postoperative kyphotic change or progression of the ossified lesion.

CONCLUSIONS

Segmental instability, a degenerative dynamic factor, is important to the OPLL myelopathy. The posterior hybrid technique seemed to be effective and safe in the treatment of selective OPLL patients associated with SI. The benefits may include providing stabilization environment for spinal cord recovery, and preventing progressive kyphotic change and progression of OPLL.

Trauma-induced spinal cord injury in cervical spondylotic myelopathy with or without lower cervical instability

Dynamic factors are important contributors to neurologic deficits in cervical spondylotic myelopathy (CSM) patients. Between 2005 and 2009, we retrospectively investigated 72 patients with CSM with or without lower cervical instability for their neurologic status after low-energy trauma and surgery. Patients were divided into two groups: the instability group and the stability group. The neurologic status was evaluated using the Japanese Orthopaedic Association (JOA) scoring system. The incidence of neurologic deterioration after trauma was higher in patients with lower cervical instability than in those without (p<0.05). Patients in the instability group had a lower preoperative JOA score (p<0.05) and experienced less post-surgery improvement in neurologic function than those in the stability group (p<0.01). Even a minor trauma to the neck can lead to irreversible spinal cord injury for patients with CSM with cervical instability. Eliminating local instability through surgical and non-surgical methods is necessary for such patients before decompression and fusion surgery.

Surgical management of cervical cord injury with ossification of the cervical posterior longitudinal ligament

OBJECTIVE

To identify an appropriate surgical approach for the management of cervical cord injury with ossification of the posterior longitudinal ligament.

METHODS

A retrospective study of 25 cases of cervical cord injury with ossification of the posterior longitudinal ligament was performed. Two cases were classified as Frankel grade A, three as grade B, fourteen as grade C, and six as grade D. Treatment procedures consisted of anterior decompression with instrumentation (twelve patients), posterior decompression (eight patients), and combined anterior and posterior decompression (five patients).

RESULTS

There were no iatrogenic injuries of great vessels, trachea, esophagus or spinal cord. All patients were followed up for 15-86 months (average, 38.3 months). All segment with anterior fixation attained solid fusion, without implants loosening or breakage. No reclosed open-door was found after posterior laminoplasty. Twenty-one patients improved by one to two Frankel grades. The patients with complete spinal cord injury achieved no neurologic recovery, but did experience relief of upper limb pain or numbness.

CONCLUSION

The surgical outcomes of cervical cord injury with ossification of the posterior longitudinal ligament were satisfactory. It is important to select a suitable surgical approach according to the findings on radiological imaging and the clinical characteristics and general condition of the patients.

Conservative management of ossification of the posterior longitudinal ligament. A review

OBJECT

Ossification of the posterior longitudinal ligament (OPLL) can result in significant myelopathy. Surgical treatment for OPLL has been extensively documented in the literature, but less data exist on conservative management of this condition.

METHODS

The authors conducted a systematic review to identify all reported cases of OPLL that were conservatively managed without surgery.

RESULTS

The review yielded 11 published studies reporting on a total of 480 patients (range per study 1-359 patients) over a mean follow-up period of 14.6 years (range 0.4-26 years). Of these 480 patients, 348 (72.5%) were without myelopathy on initial presentation, whereas 76 patients (15.8%) had signs of myelopathy; in 56 cases (15.8%), the presence of myelopathy was not specified. The mean aggregate Japanese Orthopaedic Association score on presentation for 111 patients was 15.3. Data available for 330 patients who initially presented without myelopathy showed progression to myelopathy in 55 (16.7%), whereas the other 275 (83.3%) remained progression free. In the 76 patients presenting with myelopathy, 37 (48.7%) showed clinical progression, whereas 39 (51.5%) remained clinically unchanged or improved.

CONCLUSIONS

Patients who present without myelopathy have a high chance of remaining progression free. Those who already have signs of myelopathy at presentation may benefit from surgery due to a higher rate of progression over continued follow-up.

Conservatively treated ossification of the posterior longitudinal ligament increases the risk of spinal cord injury: a nationwide cohort study

The optimal treatment strategy for ossification of the posterior longitudinal ligament (OPLL) depends on symptoms and is uncertain. Whether the risk of spinal cord injury (SCI) is increased in patients with cervical spinal stenosis or myelopathy caused by OPLL remains unclear. This study aimed to evaluate the risk of SCI in patients with OPLL of the cervical spine when managed with conservative treatment (no surgery). Study subjects were identified from a nationwide cohort of 26,544,883 people from 1998 to 2005 and were divided into the OPLL group (n=265), who were hospitalized for OPLL but had conservative treatment (no surgery), and the comparison group (n=5339), composed of age- and sex-matched people. Until the end of 2008, a total of 5604 subjects were followed-up for 34,723.5 person-years. The propensity score method was used to adjust for covariates. Kaplan-Meier and Cox regression analyses were performed. The incidence rate of cervical SCI in the OPLL group was found to be significantly higher than in the comparison group (4.81 versus 0.18 per 1000 person-years; p<0.001). Cervical SCI was more likely to happen in the OPLL group than in the comparison group (crude hazard ratio [HR] 25.64; p<0.001). After adjustments, the OPLL group had a 32.16-fold (p<0.001) higher risk for cervical SCI. Disability caused by SCI had an even higher risk (HR=110.72, adjusted HR=104.78; p<0.001) for the OPLL group. Therefore, cervical SCI and related disabilities are more likely to happen in OPLL patients, who should be cautioned for subsequent SCI if treated conservatively.

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.

Cervical cord injury in patients with ankylosed spines: progressive paraplegia in two patients after posterior fusion without decompression

STUDY DESIGN

Case report and clinical discussion.

OBJECTIVE

To describe technical pitfall to treat 2 cervical cord injuries, including dislocations in patients with ankylosed spine due to diffuse idiopathic skeletal hyperostosis (DISH) or ossification of the posterior longitudinal ligament (OPLL).

SUMMARY OF BACKGROUND DATA

DISH and OPLL are disease processes similar in pathology, which can lead to unexpected fractures due to low-energy trauma. In reported cases of fracture of the ankylosed spine in patients with DISH or OPLL, increasing lever arm and a grossly unstable fracture occurred. However, the actual surgical intervention for these fractures and spinal cord injuries was not discussed.

METHODS

We report 2 cervical cord injuries, including dislocations in patients with ankylosed spine due to DISH or OPLL.

RESULTS

Two patients underwent posterior fusion without decompression; however, postoperative progressive paraplegia still occurred. There were 3 points in common: these patients had ankylosed spines due to DISH or OPLL; they were elderly and had spinal canal stenosis; and after undergoing posterior fusion without decompression, their bilateral, lower extremity palsies worsened after surgery. Cervical alignment was slightly different after posterior fusion, and this change concentrated in one segment because adjacent vertebral bodies were ankylosed, and thus, immoveable. Additionally, this stress caused infolding of the ligamentum flavum with resultant spinal cord compression.

CONCLUSION

In these cases, we recommend posterior fusion and decompression such as laminoplasty to avoid worsening palsy.

Does ossification of the posterior longitudinal ligament affect the neurological outcome after traumatic cervical cord injury?

STUDY DESIGN

Retrospective outcome measurement study.

OBJECTIVES

The purpose of this study is to assess whether ossification of the posterior longitudinal ligament (OPLL) affects neurologic outcomes in patients with acute cervical spinal cord injury (SCI).

SUMMARY OF BACKGROUND DATA

There have so far been few reports examining the relationship between OPLL and SCI and there is controversy regarding the deteriorating effects of OPLL-induced canal stenosis on neurologic outcomes.

METHODS

To obtain a relatively uniform background, patients nonsurgically treated for an acute C3-C4 level SCI without any fractures or dislocations of the spinal column were selected, resulting in 129 patients. There were 110 men and 19 women (mean age was 61.1 years), having various neurologic conditions on admission (American Spinal Injury Association [ASIA] impairment scale A, 43; B, 16; C, 58; D, 12). The follow-up period was the duration of their hospital stay and ranged from 50 to 603 days (mean, 233 days). The presence of OPLL, the cause of injury, the degree of canal stenosis (both static and dynamic), and the neurologic outcomes in motor function, including improvement rate, were assessed.

RESULTS

Of the 129 patients investigated in this study, OPLL was identified at the site of the injury in 13 patients (10.1%). In this OPLL+ group, the static and dynamic canal diameters at C3 and C4 were significantly smaller than those of the remaining 116 patients (OPLL- group). However, no significant difference was observed between the 2 groups in terms of ASIA motor score both at the time of administration and discharge, and the mean improvement rate in ASIA motor score was 55.5 +/- 9.0% in OPLL+ group, while it was 43.1 +/- 2.8% in the OPLL-group. Furthermore, no significant correlation was observed between the static/dynamic canal diameters and neurologic outcome in all 129 patients.

CONCLUSION

No evidence was found for OPLL to have any effect on the initial neurologic status or recovery in motor function after traumatic cervical cord injury, suggesting that the neurologic outcome is not significantly dependent on canal space.

Two-staged decompression for thoracic paraparesis due to the combined ossification of the posterior longitudinal ligament and the ligamentum flavum: a case report

STUDY DESIGN

A case report of ossification of the posterior longitudinal ligament (OPLL) combined with ossification of the ligamentum flavum, or yellow ligament (OYL), in the upper thoracic spine.

OBJECTIVE

To describe a rare clinical entity and its management pitfalls in a patient with upper thoracic myelopathy due to combined OPLL and OYL.

METHODS

A 52-year-old woman developed paresthesia and paraparesis of both legs. One month prior to admission she fell and became unable to walk. She was diagnosed as having upper thoracic myelopathy due to combined OPLL and OYL and was treated by two-stage anterior and posterior spinal decompression. Posterior decompression was achieved first by laminoplasty at C3-Th1 and laminectomy of Th2 and Th3.

RESULTS

After posterior decompression, her symptoms immediately and dramatically improved. However, symptoms recurred after she was able to achieve a sitting or standing position. We then performed anterior decompression at Th2, which again improved her symptoms. At two years post-surgery, she is ambulatory with the use of a cane.

CONCLUSION

Upper thoracic myelopathy due to OPLL and OYL was treated by combined 2-staged anterior and posterior decompression. In this case, posterior decompression alone was inadequate to relieve the symptoms of this pathological condition.

Tetraparesis secondary to cervical ossification of the posterior longitudinal ligament: case report

Ossification of the posterior longitudinal ligament (OPLL) is a rare cause of myelopathy in non-Oriental populations and relatively unrecognized by general practitioners. A case of an Afro-Brazilian 54-years-old woman presenting with tetraparesis due to cervical OPLL is presented. Emphasis is made for the inclusion of OPLL in the differential diagnosis of compressive cervical myelopathy.

Ossificação do ligamento longitudional posterior: relato de caso

Ossificação do ligamento longitudinal posterior (OLLP) cervical é patologia rara em nosso meio que pode ser tratada por abordagem anterior ou posterior da coluna. Relatamos o caso de um homem japonês de 42 anos com paraparesia progressiva e TC e RM comprovando o diagnóstico de OLLLP, submetido a corpectomia anterior com artrodese. A fisiopatologia desta entesopatia, prevalência racial, quadro clínico, características radiológicas e opções do procedimento cirúrgico são revistos.

Clinical evaluation of traumatic central cord syndrome: emphasis on clinical significance of prevertebral hyperintensity, cord compression, and intramedullary high-signal intensity on magnetic resonance imaging

BACKGROUND

We evaluated the prognostic and clinical value of radiological findings including prevertebral hyperintensity (HI), cord compression, intramedullary high-signal intensity (IMHSI) and instability in patients with traumatic central cord syndrome without evidence of fracture and dislocation.

METHODS

The radiological and clinical findings of 23 patients who had undergone surgery between 1996 and 2002 were reviewed retrospectively. All of the patients underwent dynamic motion study and magnetic resonance (MR) imaging after trauma. Neurologic status was evaluated with American Spinal Injury Association motor score pre- and postoperatively and compared with the radiological findings. Anterior decompression and fusion were performed in 12 patients with 1- or 2-level lesions, and posterior decompression was done for 11 cases of multilevel lesions.

RESULTS

Prevertebral HI was found in 17 patients. Among them, instability was revealed in 11 patients. There was significant correlation between prevertebral HI and instability (P = .014). Cord compression was found in varying degrees in all patients on MR imaging. Intramedullary high-signal intensity was found preoperatively in 19 (83%) of 23 patients, and it was revealed at the most compressed level of the spinal cord in all cases. The neurologic level was consistent with the level of instability (100%), IMHSI (95%), and cord compression (87%). Mean American Spinal Injury Association motor scores in patients with instability were lower than in those without instability (P < .05).

CONCLUSIONS

The presence of prevertebral HI, IMHSI, and cord compression influenced the neurologic status of the patients. The instability was significantly associated with poor prognosis for neurologic outcome. Prevertebral HI on T2 MR imaging may be a possible indicator of instability in patients with central cord syndrome after hyperextension injury.

Cervical cord compression secondary to ossification of the posterior longitudinal ligament

STUDY DESIGN

Resident's case problem.

BACKGROUND

A 52-year-old Chinese male with a 10-year history of gradually worsening right hip stiffness, weakness, and pain was referred to physical therapy by his orthopedist, who made a diagnosis of developmental dysplasia of the right hip, with possible Legg-Calve-Perthes disease. The patient reported multiple falls over the last several years and a gradual onset of low back pain with an onset of "electricity" down both legs. The patient also reported mild numbness in both forearms and the right hand over the previous several months. This resident's case problem illustrates how a physical therapist recognized the presence of an atypical musculoskeletal pathology through the use of hypothesis-driven clinical reasoning and detailed physical examination.

DIAGNOSIS

Examination of the patient's lumbar and cervical spine and hips revealed joint dysfunctions. Neurological testing revealed hyperreflexia. Special testing revealed lower extremity clonus with a positive Babinski sign with gait disturbances. The patient was referred back to his primary physician and then to a neurologist and neurosurgeon. An MRI revealed cervical myelopathy due to ossification of the posterior longitudinal ligament from C3/C4 to C5/C6. The patient then underwent a C3 through C7 laminectomy.

DISCUSSION

It is always imperative that sound clinical reasoning be used when performing physical therapy evaluations, regardless of the referral status of the patient. Patients with nonmusculoskeletal pathology may seek physical therapy services and it is the physical therapist's responsibility to complete a thorough examination and refer to specialists when appropriate.