Effect of posterior instrumented fusion on three-dimensional volumetric growth of cervical ossification of the posterior longitudinal ligament: a multiple regression analysis

Sorafenib inhibits ossification of the posterior longitudinal ligament by blocking LOXL2-mediated vascularization

Ossification of the Posterior Longitudinal Ligament (OPLL) is a degenerative hyperostosis disease characterized by the transformation of the soft and elastic vertebral ligament into bone, resulting in limited spinal mobility and nerve compression. Employing both bulk and single-cell RNA sequencing, we elucidate the molecular characteristics, cellular components, and their evolution during the OPLL process at a single-cell resolution, and validate these findings in clinical samples. This study also uncovers the capability of ligament stem cells to exhibit endothelial cell-like phenotypes in vitro and in vivo. Notably, our study identifies LOXL2 as a key regulator in this process. Through gain-and loss-of-function studies, we elucidate the role of LOXL2 in the endothelial-like differentiation of ligament cells. It acts via the HIF1A pathway, promoting the secretion of downstream VEGFA and PDGF-BB. This function is not related to the enzymatic activity of LOXL2. Furthermore, we identify sorafenib, a broad-spectrum tyrosine kinase inhibitor, as an effective suppressor of LOXL2-mediated vascular morphogenesis. By disrupting the coupling between vascularization and osteogenesis, sorafenib demonstrates significant inhibition of OPLL progression in both BMP-induced and enpp1 deficiency-induced animal models while having no discernible effect on normal bone mass. These findings underscore the potential of sorafenib as a therapeutic intervention for OPLL.

True Continuous Segment of Ossification of Posterior Longitudinal Ligament is Protective Against Postoperative Early Kyphosis Progression After Laminoplasty

BACKGROUND AND OBJECTIVES

Ossification of the posterior longitudinal ligament (OPLL) is a potentially catastrophic disease. Laminoplasty (LP) is a common surgical intervention, but postoperative kyphosis progression is a major complication, for which various risk factors have been identified and used in surgical decision-making. Our focus is on the ability of OPLL with specific morphological traits, designated as the true continuous segment (TCS), to stabilize alignment and prevent postoperative kyphosis after LP.

METHODS

This retrospective case-control study included patients who underwent cervical LP for OPLL treatment with a minimum 1-year follow-up. Demographic, operative, and radiographic parameters were analyzed. TCS is defined as a continuous segment of OPLL that spans the disk space more than half of the adjacent vertebral body height without crack, or OPLL segment attached to both upper and lower adjacent vertebral bodies by bridging, or obvious interbody autofusion, and is identified from preoperative computed tomography. A subgroup analysis for preoperatively lordotic patients, divided into 2 groups based on cervical alignment at the final follow-up, was conducted to identify risk factors for kyphosis progression. Difference analysis, linear regression analysis for loss of lordosis (LoL), and logistic regression analysis for kyphosis progression were used.

RESULTS

A total of 84 patients were identified. Among them, 78 patients with preoperatively lordotic alignment were divided into 2 groups: those who maintained lordotic alignment (n = 60) and those who progressed to kyphosis (n = 18). Regression analyses revealed a significant protective effect of TCS count against LoL and postoperative kyphosis, with a TCS count of 3 or more conclusively preventing kyphosis (sensitivity 1.000, specificity 0.283, area under the curve 0.629).

CONCLUSION

For patients with OPLL, TCS was shown to protect against the LoL after LP. Therefore, TCS should be identified and considered when planning surgical treatment for OPLL.

Optimizing the Application of Surgery for Degenerative Cervical Myelopathy [AO Spine RECODE-DCM Research Priority Number 10]

STUDY DESIGN

Literature Review (Narrative).

OBJECTIVE

To introduce the number 10 research priority for Degenerative Cervical Myelopathy: Individualizing Surgery.

METHODS

This article summarizes the current recommendations and indications for surgery, including how known prognostic factors such as injury time, age, disease severity, and associated comorbidities impact surgical outcome. It also considers key areas of uncertainty that should be the focus of future research.

RESULTS

While a small proportion of conservatively managed patients may remain stable, the majority will deteriorate over time. To date, surgical decompression is the mainstay of treatment, able to halt disease progression and improve neurologic function and quality of life for most patients. Whilst this recognition has led to recommendations on when to offer surgery, there remain many uncertainties including the type of surgery, or timing in milder and/or asymptomatic cases. Their clarification has the potential to transform outcomes, by ensuring surgery offers each individual its maximum benefit.

CONCLUSION

Developing the evidence to better guide surgical decision-making at the individual patient level is a research priority for Degenerative Cervical Myelopathy.

Laminectomy with instrumented fusion vs. laminoplasty in the surgical treatment of cervical ossification of the posterior longitudinal ligament: A multicenter retrospective study

Laminectomy with instrumented fusion (LF) has demonstrated better prevention of ossification of posterior longitudinal ligament (OPLL) growth compared to laminoplasty (LP). There remains uncertainty, however, as to which surgical approach is more beneficial with respect to clinical outcomes and complications. We retrospectively reviewed 273 cervical OPLL patients of more than 3 levels, from the two institutions' databases, who underwent LF or LP between January 1998 and January 2016. Each 273 patient (85 with LF, 188 with LP) was assessed for postoperative neurologic and radiologic outcomes, complications and reoperations. The mean length of follow-up was 40.11 months. There were baseline differences between cohorts. Overall, postoperative JOA recovery rate at last follow up was significantly better in the LP group with similar improvement in visual analog neck score. Postoperative C2-7 Cobb angle was decreased compared to baseline for both LF and LP cohorts, but there was no significant difference between groups. Complications occurred in 19 (22.35%) LF patients, and 11 (5.85%) LP patients, with higher incidence of C5 palsy and instrumentation failure in the LF group. Four LF patients (4.71%) and five LP patients (2.66%) underwent reoperation during the follow up period.

Deep learning algorithm based on analyzing the effect of posterior cervical vertebral canal decompression angioplasty in the treatment of ossification of posterior longitudinal ligament of cervical spine by CT image

Objective:

The paper uses the convolutional neural network algorithm in the deep learning algorithm to explore the therapeutic effect of surgical treatment of hyperextension injuries associated with ossification of the posterior longitudinal ligament of the cervical spine.

Methods:

In this retrospectively analyzed study 27 patients with hyperextension injury of the posterior longitudinal ligament of the cervical spine were selected from our hospital between August 2018 to July 2020. It included 21 males and 6 females; aged 36-79 years, with an average of 55.9 years.

Results:

Follow-up time of patients was 3-39 months, with an average of 17.4 months. The JOA score after surgery was significantly better than that before surgery (P<0.01), which was statistically significant; the improvement of JOA in patients undergoing anterior therapy was better than that in patients undergoing posterior therapy, which was statistically significant; the JOA improved in patients with minor violent injuries. The situation is significantly better than severe violent injuries, with statistical significance. The rate of postoperative JOA improvement was significantly correlated with the degree of nerve function retention of the injured spinal cord before surgery (P<0.01), and there was no significant correlation between the degree of spinal stenosis caused by ossification and the postoperative JOA improvement of patients.

Conclusion:

Convolutional neural network algorithm in the deep learning algorithm based on the cervical spine posterior longitudinal ligament ossification hyperextension injury was significantly improved after surgery. The less preoperative neurological damage, the postoperative neurological function, the degree of improvement, there was no significant correlation between the degree of spinal stenosis and the improvement of postoperative spinal cord function. For patients with ossification of the posterior longitudinal ligament, if there are neurological symptoms, early surgical treatment is recommended to relieve the compression, so as to prevent irreversible neurological damage caused by trauma.

The Relative Merits of Posterior Surgical Treatments for Multi-Level Degenerative Cervical Myelopathy Remain Uncertain: Findings from a Systematic Review

Objectives: To assess the reporting of study design and characteristics in multi-level degenerative cervical myelopathy (DCM) treated by posterior surgical approaches, and perform a comparison of clinical and radiographic outcomes between different approaches. Methods: A literature search was performed in Embase and MEDLINE between 1995–2019 using a sensitive search string combination. Studies were selected by predefined selection criteria: Full text articles in English, with >10 patients (prospective) or >50 patients (retrospective), reporting outcomes of multi-level DCM treated by posterior surgical approach. Results: A total of 75 studies involving 19,510 patients, conducted worldwide, were identified. Laminoplasty was described in 56 studies (75%), followed by laminectomy with (36%) and without fusion (16%). The majority of studies were conducted in Asia (84%), in the period of 2016–2019 (51%), of which laminoplasty was studied predominantly. Twelve (16%) prospective studies and 63 (84%) retrospective studies were identified. The vast majority of studies were conducted in a single centre (95%) with clear inclusion/exclusion criteria and explicit cause of DCM. Eleven studies (15%) included patients with ossification of the posterior longitudinal ligament exclusively with cohorts of 57 to 252. The clinical and radiographic outcomes were reported with heterogeneity when comparing laminoplasty, laminectomy with and without fusion. Conclusions: Heterogeneity in the reporting of study and sample characteristics exists, as well as in clinical and radiographic outcomes, with a paucity of studies with a higher level of evidence. Future studies are needed to elucidate the clinical effectiveness of posterior surgical treatments.

Comparison of Interventions for Cervical Ossification of Posterior Longitudinal Ligament: A Systematic Review and Network Meta-Analysis

OBJECTIVE

To summarize the literature and systematically evaluate outcomes for ossification of posterior longitudinal ligament interventions including anterior cervical corpectomy and fusion (ACCF), anterior controllable antedisplacement and fusion (ACAF), laminoplasty (LP), and laminectomy with fusion (LF).

METHODS

We searched PubMed, Embase, Web of Science, and the Cochrane Library from January 1990 to March 2021. Patient demographic data, Japanese Orthopaedic Association score, cervical lordosis and overall complications were analyzed.

RESULTS

We evaluated 30 studies involving 2038 patients. Patients undergoing ACCF had improved Japanese Orthopaedic Association scores compared with patients undergoing LP (weighted mean difference [WMD] 1.17, 95% confidence interval [CI] 0.49-1.85) and LF (WMD 1.21, 95% CI 0.17-2.24). Patients with ACAF had better cervical lordosis compared with patients with ACCF (WMD 7.00, 95% CI 0.72-13.27), LP (WMD 10.27, 95% CI 4.64-15.90), and LF (WMD 8.98, 95% CI 2.48-15.47). Additionally, ACAF (odds ratio 0.24, 95% CI 0.07-0.84) and LP (odds ratio 0.50, 95% CI 0.28-0.90) had a lower incidence of complications compared with ACCF.

CONCLUSIONS

Japanese Orthopaedic Association score outcomes indicated that ACCF was superior to LP and LF. ACAF had the largest cervical lordosis among all procedures. ACCF showed a higher incidence of overall complications compared with ACAF and LP.

The clinical value of three-dimensional measurement in the diagnosis of thoracic myelopathy caused by ossification of the ligamentum flavum

Background

Thoracic ossification of the ligamentum flavum (OLF) is a major cause of thoracic myelopathy, which is often accompanied by multiple segmental stenosis or other degenerative spinal diseases. However, in the above situations, it is difficult to determine the exact segment responsible. The objective of this study was to analyze three-dimensional (3D) radiological parameters in order to establish a novel diagnostic method for discriminating the responsible segment in OLF-induced thoracic myelopathy, and to evaluate its superiority compared to the conventional diagnostic methods.

Methods

Eighty-one patients who underwent surgery for thoracic myelopathy caused by OLF from 2016 to 2020 were enrolled in this study as the myelopathy group, and 79 patients who had thoracic OLF but displayed no definite neurological signs from 2018 to 2020 were enrolled as the non-myelopathy group. We measured the one-dimensional (1D), two-dimensional (2D), and 3D radiological parameters, calculated their optimal cutoff values, and compared their diagnostic values.

Results

Significant differences were observed in the 1D, 2D, and 3D radiological parameters between the myelopathy and non-myelopathy groups (P<0.01). As a 3D radiological parameter, the OLF volume (OLFV) ratio (OLFV ratio = OLFV/normal canal volume × 100%) was the most accurate parameter for diagnosing OLF-induced thoracic myelopathy, with a diagnostic coincidence rate of 88.1%. We also found that an OLFV ratio of 26.3% could be used as the optimal cutoff value, with a sensitivity of 87.7% and a specificity of 88.6%. Moreover, the OLFV ratio [area under the curve (AUC): 0.92, 95% confidence interval (CI): 0.86-0.95] showed a statistically higher diagnostic value than the 1D and 2D parameters (AUC: 0.75, 95% CI: 0.67-0.81; AUC: 0.84, 95% CI: 0.77-0.89, respectively) (P<0.05). Pearson correlation analysis illustrated that the OLFV ratio was significantly negatively correlated with preoperative modified Japanese Orthopedic Association (mJOA) score (r=-0.73, 95% CI: -0.81 to -0.60, P<0.01).

Conclusions

Our results demonstrate the superiority of the OLFV ratio over the conventional 1D and 2D computed tomography (CT)-based radiological parameters for the diagnosis of OLF-induced thoracic myelopathy. The novel diagnostic method based on the OLFV ratio will help to determine the responsible segment in multi-segmental thoracic OLF or when thoracic OLF coexists with other degenerative spinal diseases. The OLFV ratio also accurately reflects the clinical state of symptomatic patients with thoracic OLF.

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

Background

Cervical ossification of the posterior longitudinal ligament (OPLL) causes spinal cord compression, which can lead to myelopathy or radiculopathy. Non-surgical treatments have little effect on this condition. Current OPLL classification systems offer little guidance on the selection of an appropriate operating procedure. In this study, we developed a modified axial computed tomography classification (MACTC) scheme. We then examined the usefulness of the MACTC scheme and two other existing classification schemes in guiding OPLL operation choice.

Methods

Following screening in which a defined exclusion criteria was used, a total of 91 patients with OPLL participated in the study. Patients' follow-up data for at least 2 years were obtained. The recovery rate of the Japanese Orthopaedic Association (JOA) scores was compared to two other classification schemes.

Results

According to the MACTC, central-sharp-type OPLL had a lower recovery rate of the JOA score than that of central-gentle-type OPLL (36.05±32.38 vs. 83.90±23.52, P≤0.05). The recovery rate of the JOA scores in the ipsilateral open-door OPLL group was significantly lower than that in the contralateral group of the lateral-steep type (36.67±41.5 vs. 88.89±17.21, P=0.04), but not of that in the lateral-gentle type. There was no significant difference in the recovery rates of the JOA scores between groups when using either existing classification scheme (P>0.05).

Conclusions

The MACTC scheme can assist surgeons to choose the most appropriate operating procedure, and provide an accurate prognosis. If operations on central-sharp-type OPLL are not performed using both the posterior and anterior approaches, prognosis will be poor. The contralateral side should be the first choice for door opening in laminoplasty, especially for patients with lateral-steep-type OPLL. Severe OPLL may not be an absolute contraindication for the posterior approach.

How much space of the spinal canal should be restored by hoisting the vertebrae-OPLL complex for sufficient decompression in anterior controllable antedisplacement and fusion? A multicenter clinical radiological study

BACKGROUND CONTEXT

Anterior controllable antedisplacement and fusion (ACAF) is a novel surgical technique for the treatment of ossification of the posterior longitudinal ligament (OPLL). Its prognostic factors for decompression have not been well studied. Additionally, no detailed radiological standard has been set for hoisting the vertebrae-OPLL complex (VOC) in ACAF.

PURPOSE

To identify the possible prognostic factors for decompression outcomes after ACAF for cervical OPLL, to determine the critical value of radiological parameters for predicting good outcomes, and to establish a radiological standard for hoisting the VOC in ACAF.

STUDY DESIGN

This was a retrospective multicenter study.

PATIENT SAMPLE

A total of 121 consecutive patients with OPLL who underwent ACAF at a point between January 2017 and June 2018 at any one of seven facilities and were monitored for at least 1 year afterward were enrolled in a multicenter study.

OUTCOME MEASURES

Japanese Orthopedic Association (JOA) scores, recovery rate (RR) of neurologic function, and surgical complications were used to determine the effectiveness of ACAF.

METHODS

Patients were divided into two groups according to their RR for neurologic function. Patients with an RR of ≥50% and an RR of <50% were designated as having good and poor decompression outcomes, respectively. The relationship between various possible prognostic factors and decompression outcomes was assessed by univariate and multivariate analysis. The receiver operating characteristic curve was used to determine the optimal cutoff value of the radiological parameters for prediction of good decompression outcomes. Next, the patients were redivided into three groups according to the cutoff value of the selected radiological parameter (postoperative anteroposterior canal diameter [APD] ratio). Patients with postoperative APD ratios of ≤80.7%, 80.7%-100%, and ≥100% were defined as members of the incomplete, optimal, and excessive antedisplacement groups, respectively. Differences in decompression outcomes among the three groups were compared to verify the reliability of the postoperative APD ratio and assess the necessity of excessive antedisplacement.

RESULTS

Multivariate logistic regression analysis showed that patients' age at surgery (odds ratio [OR]=1.18; 95% confidence interval [CI]=1.08-1.29; p<.01) and postoperative APD ratio (OR=0.83; 95% CI=0.77-0.90; p<.01) were independently associated with decompression outcomes. The optimal cutoff point of the postoperative APD ratio was calculated at 80.7%, with 86.2% sensitivity and 73.5% specificity. There were no significant differences in the postoperative JOA scores and RRs between the excessive antedisplacement group and optimal antedisplacement group (p>.05). However, a lower incidence of cerebrospinal fluid leakage and screw slippage was observed in the optimal antedisplacement group (p<.05).

CONCLUSIONS

Patients' age at surgery and their postoperative APD ratio are the two prognostic factors of decompression outcomes after ACAF. The postoperative APD ratio is also the most accurate radiological parameter for predicting good outcomes. Our findings suggest that it is essential for neurologic recovery to restore the spinal canal to more than 80.7% of its original size (postoperative APD ratio >80.7%), and restoration to less than its original size (postoperative APD ratio <100%) will help reduce the incidence of surgical complications. This may serve as a valuable reference for establishment of a radiological standard for hoisting the VOC in ACAF.

Surgical decision-making for ossification of the posterior longitudinal ligament versus other types of degenerative cervical myelopathy: anterior versus posterior approaches

Background

The debate between anterior or posterior approach for pathologies such as cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) have drawn heated debate but are still inconclusive.

Main body of the abstract

A narrative review was performed specifically to study the differences pertaining to OPLL and other causes of degenerative cervical myelopathy (DCM). Current evidence suggests that anterior approach is preferred for K-line (−) OPLL, K-line (+) with canal occupying ratio > 60% and DCM with pre-existing cervical kyphosis. Posterior approach is preferred for K-line (+) OPLL with canal-occupying ratio < 50–60%, and multi-level CSM. No particular advantage for either approach was observed for DCM in a lordotic cervical spine. Anterior approach is generally associated with more complications and thus needs to be weighed carefully during decision-making. The evidence is not convincing for comparing single versus multi-level involvement, and the role of patients' co-morbidity status, pre-existing osteoporosis and co-existent spinal pathologies in influencing patient outcome and surgical options. This should be a platform for future research directives.

Conclusion

From this review, evidence is still inconclusive but there are some factors to consider, and DCM and OPLL should be considered separately for decision-making. Anterior approach is considered for pre-existing cervical kyphosis in DCM, for K-line (−) regardless of canal-occupying ratio, and K-line (+) and canal-occupying ratio > 60% for OPLL patients. Posterior approach is considered for patients with multi-level pathology for DCM, and K-line (+) and canal-occupying ratio < 50–60% for OPLL.

Effect of K-line on posterior cervical surgery in patients with posterior longitudinal ligament ossification

PURPOSE

To evaluate the effect of K-line on posterior single-door decompression with fusion fixation (PFF) and posterior single-door decompression with non-fusion fixation (PNF) for patients with ossification of posterior longitudinal ligament (OPLL).

METHODS

A total of 65 patients with OPLL were analyzed retrospectively. They consisted of 44 patients with positive K-line, designated as the K ( +) group, and 21 patients with negative K-line, designated as K (-). The patients were also divided into a PFF group (38 patients) and a PNF group (27 patients). The Japanese Orthopaedic Association (JOA) score, C2-C7 Cobb angle, improvement rate of JOA score, and complications were calculated and statistically analyzed between the groups.

RESULTS

In the K ( +) group, there were no significant differences in the incidence of C5 nerve root palsy and C2-C7 Cobb angle between the two groups of surgical patients, but there were significant differences in the improvement rate of JOA score and the incidence of axial pain. In the K (-) group, there were no significant differences in the incidence of axial pain, the incidence of C5 nerve root palsy, and preoperative C2-C7 Cobb angle between the two groups, but significant differences were observed in the improvement rate of JOA score and C2-C7 Cobb angle at the last follow-up.

CONCLUSION

In the K ( +) group, the improvement rate of JOA score was higher and the incidence of axial pain was lesser in the PNF group than in the PFF group. In the K (-) group, the improvement rate of JOA score was higher in the PFF group than in the PNF group, and there was significant loss of C2-C7 Cobb angle in the PNF group.

Anterior controllable antidisplacement and fusion surgery for the treatment of extensive cervico-thoracic ossification of posterior longitudinal ligament with severe myelopathy: case report and literature review

OPLL generally occurs in the cervical spine and involves no more than three vertebral segments, while extensive OPLL that involves the cervico-thoracic spine and spans over multiple segments is rare. Surgically it is difficult to achieve a satisfactory clinical outcome without surgical complications via the traditional anterior or posterior approaches. We report the first application of Anterior controllable antidisplacement and fusion (ACAF) in treating extensive cervico-thoracic OPLL. A 45-year old patient experienced severe walking disturbance, bladder and bowel dysfunction for 5 months after a fall. His preoperative Japanese Orthopedic Association (JOA) score was 8 of 17. Preoperative CT and MRI demonstrated a K-line (-) and mixed-type extensive OPLL from C2 to T2, causing significant cord compression. After ACAF surgery, neurological symptoms improved immediately without postoperative complications. Postoperative CT and MRI scanning showed restoration of spinal canal cross section and cord decompression. At 6 months he was able to stand and walk again without assistance and urinary bladder and bowel function returned to normal completely. At 15 months his JOA score was 14 of 17. ACAF surgery provides a promising alternative for the treatment of extensive cervico-thoracic OPLL.

Three-Dimensional Analysis of the Radiological Risk Factors for Progression of the Thoracic Ossification of the Posterior Longitudinal Ligament After Posterior Decompression and Stabilization

BACKGROUND

Although research shows that the ossified masses of ossification of the posterior longitudinal ligament (OPLL) continue to grow postoperatively, information regarding thoracic OPLL (T-OPLL) is lacking. To date, no study has investigated the progression of T-OPLL within each motion segment. The purpose of this study was to analyze the progression of T-OPLL in each motion segment using a 3-dimensional measurement and evaluate whether the type of T-OPLL and surgical methods affect its progression postoperatively.

METHODS

Clinical data from 20 patients (101 segments) with thoracic myelopathy secondary to OPLL were evaluated retrospectively. All patients underwent posterior decompression (laminectomy and stabilization or circumferential decompression [CD] and stabilization) at a single center. The 3-dimensional measurement of OPLL volume was performed using computed tomography scans. The ossified masses were classified into 2 types based on the fusion of each segment at the intervertebral space: type 1 = complete bridging (fused); type 2 = not fused. Statistical analyses were performed to determine the degree of T-OPLL progression according to the types and surgical methods.

RESULTS

Mean OPLL progression was significantly higher in type 2. The mean annual growth rates of OPLL (AGRO) for groups 1 and 2 were 6.21% ± 6.11% per year and 23.50% ± 11.34% per year, respectively (P < 0.01). Further, no statistically significant differences were seen between the fixed and non-fixed groups (P = 0.23), and CD and non-CD segments (P = 0.56).

CONCLUSIONS

The mean AGRO does not decrease even after stabilization and CD. Type 2 intervertebral space was a risk factor for T-OPLL progression. Cases of type 2 without CD need close follow-up.

Extended Laminoplasty for Ossification of Posterior Longitudinal Ligament Involving the C2 Segment

BACKGROUND

To evaluate effectiveness and safety of extended laminoplasty for the treatment of ossification of posterior longitudinal ligament (OPLL) involving the C2 segment.

METHODS

A total of 132 cases who accepted laminoplasty for treating the OPLL from 2010 to 2015 were included and divided into Group A (n = 26, with C2 OPLL and C2-C7 laminoplasty), Group B (n = 29, with C2 OPLL and C3-C7 laminoplasty), and Group C (n = 77, without C2 OPLL and had C3-C7 laminoplasty). Clinical and radiologic outcomes were compared among the 3 groups.

RESULTS

At the final visit, significant improvements in Japanese Orthopedic Association score, Neck Disability Index, Health-Related Quality-of-Life Short Form 36 Physical Component Summary, and Visual Analog Scale score in neck were observed in all 3 groups. However, all the C2-C7 Cobb angle, C2-C3 Cobb angle, sagittal vertical axis, and number of cases with cervical or segmental kyphosis in the 3 groups were not significantly changed. Although total blood loss, operation time, maximum Visual Analog Scale score in neck, incidence of axial pain, change of C2-C7, or sagittal vertical axis in Group A were all significantly larger than that in Group B or Group C, differences in neurologic recovery rate, Neck Disability Index, Health-Related Quality-of-Life Short Form 36 Physical Component Summary, change of the C2-C3 Cobb angle, and incidence of cervical or segmental malalignment among the 3 groups were not significant at the final visit.

CONCLUSIONS

If decompression indication for cases with OPLL involving the C2 segment was appropriate, extended laminoplasty up to the C2 segment could provide satisfactory neurologic recovery and would not accelerate cervical or segmental malalignment progression.

Evaluating the differences between 1D, 2D, and 3D occupying ratios in reflecting the JOA score in cervical ossification of the posterior longitudinal ligament

Background

To compare the differences between the one-dimensional (1D) length, two-dimensional (2D) area, and three-dimensional (3D) volume occupying ratios, and to assess the difference between the central and peripheral types of ossification of the posterior longitudinal ligament (OPLL).

Methods

In total, 60 patients were included in this study, and 1D and 2D occupying ratios were obtained using Centricity PACS (GE Healthcare), while a 3D model was created using MIMICS^® (Materialise, Leuven, Belgium). Clinical symptoms were measured preoperatively by the modified Japanese Orthopedic Association (JOA) score, short-form health survey (SF-36), and neck disability index. The increased signal intensity (ISI) in T2-weighted MRI was divided into three groups: grade 0, none; grade1, limited to one disc level; or grade2, beyond one disc level. The axial view of spinal canal in CT was vertically divided into three equal parts. Then, the OPLL was categorized by central and peripheral type according to the location of most protruded tip.

Results

The 1D, 2D, and 3D occupying ratios had a significantly negative relationship with JOA score (r=-0.503; -0.506; -0.516, respectively). There was little difference in the JOA score between the central and peripheral types (17.15 vs. 17.12, P=0.785). The relationship with MR ISI, according to the central and peripheral type, showed no significant difference. In each multiple regression analysis, the 1D, 2D, and 3D occupying ratios were determined to have more influence on the JOA score (Beta: -0.364, -0.411, -0.462, respectively) than age, sex, most severe level, OPLL type, location type, and MR ISI.

Conclusions

There was no difference between 1D, 2D, and 3D occupying ratios in reflecting the JOA score in cervical OPLL. Also, it is sufficient to reflect the occupying ratio in the clinical outcome without distinguishing between central and peripheral type.

Postoperative Progression of Cervical Ossification of Posterior Longitudinal Ligament: A Systematic Review

OBJECTIVE

The purpose of this study was to provide a systematic and comprehensive review of the existing literature regrading postoperative ossification of posterior longitudinal ligament (OPLL) progression.

METHODS

Using the PRISMA guidelines, we conducted an exhaustive review of electronic databases. Potential articles were screened and related information was extracted and analyzed. Twenty-four articles with low-quality evidence were included in the review. The findings of the literature review were divided into several groups: the relationship of surgery to OPLL progression; incidence and risk factors; timing and process of OPLL progression; the effect of additional instrumentation on progression; and neurologic deterioration related with progression.

RESULTS

There was no definitive conclusion for whether surgery could accelerate OPLL progression compared with the natural course. The incidence of postoperative OPLL progression was reported from 3.3% to 74.5%. Younger age, involvement of multiple levels and mixed or continuous types are recognized as risk factors. OPLL could progress transversely and longitudinally and progression in length appeared more significant than progression in thickness. Although radiologic OPLL progression was observed significantly more frequently after laminoplasty than after fusion surgery, whether additional instrumented fusion could suppress progression needs further research. Radiographic progression of OPLL did not positively correspond with neurologic deterioration.

CONCLUSIONS

The lack of high-level evidence makes it difficult to draw definite conclusions and further research and long-term follow-up clinical studies are needed to better understand postoperative OPLL progression.

Variations in Practice among Asia-Pacific Surgeons and Recommendations for Managing Cervical Myelopathy: The First Asia-Pacific Spine Society Collaborative Study

STUDY DESIGN

Surgeon survey.

PURPOSE

To study the various surgical practices of different surgeons in the Asia-Pacific region.

OVERVIEW OF LITERATURE

Given the diversity among Asia-Pacific surgeons, there is no clear consensus on the preferred management strategies for cervical myelopathy. In particular, the role of prophylactic decompression for silent cervical spinal stenosis is under constant debate and should be addressed.

METHODS

Surgeons from the Asia-Pacific Spine Society participated in an online questionnaire comprising 50 questions. Data on clinical diagnosis, investigations and outcome measures, approach to asymptomatic and silent cervical spinal stenosis, guidelines for surgical approach, and postoperative immobilization were recorded. All parameters were analyzed by the Mantel-Haenszel test.

RESULTS

A total of 79 surgeons from 16 countries participated. Most surgeons used gait disturbance (60.5%) and dyskinetic hand movement (46.1%) for diagnosis. Up to 5.2% of surgeons would operate on asymptomatic spinal stenosis, and 18.2% would operate on silent spinal stenosis. Among those who would not operate, most (57.1%) advised patients on avoidance behavior and up to 9.5% prescribed neck collars. For ossification of the posterior longitudinal ligament (OPLL), anterior removal was most commonly performed for one-level disease (p<0.001), whereas laminoplasty was most commonly performed for two- to four-level disease (p=0.036). More surgeons considered laminectomy and fusion for multilevel OPLL. Most surgeons generally preferred to use a rigid neck collar for 6 weeks postoperatively (p<0.001).

CONCLUSIONS

The pooled recommendations include prophylactic or early decompression surgery for patients with silent cervical spinal stenosis, particularly OPLL. Anterior decompression is primarily suggested for one- or two-level disease, whereas laminoplasty is preferred for multilevel disease.