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

Predictors of the Need for Surgery in Cervical Ossification of the Posterior Longitudinal Ligament: A Retrospective Cohort Longitudinal Study Using a Claims-based Database

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of this study was to determine predictors associated with the needfor cervical ossification of the posterior longitudinal ligament (cOPLL) surgery amongindividuals with cOPLL.

SUMMARY OF BACKGROUND DATA

cOPLL is a spinal disorder caused by ectopic ossification of the posterior longitudinal ligament. However, factors associated with a higher rate of surgery to treat the neurological symptoms of cOPLL are poorly understood.

MATERIALS AND METHODS

This retrospective population-based cohort study using a commercial administrative claims database from JMDC Inc. (Tokyo, Japan) enrolled patients newly diagnosed with cOPLL from April 2005 to October 2020 and followed to April 2021. A total of 1506 cOPLL patients aged 18 years or older with no history of cervical spine surgery and with a record of metabolic profiles obtained at general health checkups were included. Cox proportional hazards regression models identified patient characteristics and comorbidities associated with cOPLL surgery.

RESULTS

Of 1506 patients with cOPLL with a median of 1.8 years of follow-up after initial cOPLL diagnosis, 439 (29.2%) received cOPLL surgery. The 1-year cumulative incidence (95% CI) was 26.0% (23.7-28.2). In multivariable Cox proportional regression analysis, male (hazard ratio: 1.68; 95% CI: 1.26-2.24; P < 0.001) and obesity (body mass index: ≥25) (hazard ratio: 1.45; 95% CI: 1.10-1.89; P = 0.007) were associated with an increased risk of cOPLL surgery.

CONCLUSIONS

In this large claims-based study of adults newly diagnosed with cOPLL, males and obesity were associated with a higher risk of cOPLL surgery. These findings may help clinicians to predict the future course of cOPLL in patients, although further research is needed to elucidate the biological role of these progression-associated factors.

Characteristics of the cervical spine and cervical cord injuries in older adults with cervical ossification of the posterior longitudinal ligament

Although the incidence of cervical spinal cord injury (CSCI) with ossification of the posterior longitudinal ligament (OPLL) has increased in older adults, its etiology and neurological outcomes remain unknown. We identified OPLL characteristics and determined whether they influence neurological severity and improvement of CSCI in older patients. This multicenter retrospective cohort study identified 1512 patients aged ≥ 65 years diagnosed with CSCI on admission during 2010-2020. We analyzed CSCI etiology in OPLL patients. We performed propensity score-adjusted analyses to compare neurological outcomes between patients with and without OPLL. Cases were matched based on variables influencing neurological prognosis. The primary neurological outcome was rated according to the American Spine Injury Association (ASIA) impairment scale (AIS) and ASIA motor score (AMS). In 332 OPLL patients, the male-to-female ratio was approximately 4:1. Half of all patients displayed low-energy trauma-induced injury and one-third had CSCI without a bony injury. Propensity score matching created 279 pairs. There was no significant difference in the AIS grade and AMS between patients with and without OPLL during hospitalization, 6 months, and 12 months following injury. OPLL patients tended to exhibit worse neurological findings during injury; nevertheless, OPLL was not associated with poor neurological improvement in older CSCI patients.

Risk Factors for Poor Prognosis of Spinal Cord Injury without Radiographic Abnormality Associated with Cervical Ossification of the Posterior Longitudinal Ligament

Purpose

To investigate the factors associated with the prognosis of spinal cord injury without radiographic abnormality (SCIWORA) accompanied by cervical ossification of the posterior longitudinal ligament (C-OPLL).

Methods

We retrospectively investigated 287 patients with SCIWORA associated with C-OPLL, who were admitted within 30 days after trauma to our facility between August 2014 and August 2018. All patients were divided into the good or poor prognosis group. Patient demographics were analyzed. Besides, occupying ratio on CT and spinal cord high signal changes in MRI T2WI were measured and recorded. Multivariate linear regression was applied to analyze the correlation of prognosis with spinal cord high signal changes in MRI T2WI, cause of injury, and occupying ratio.

Results

Occupying ratio of ossification mass was 43.5 ± 10.7% in the poor prognosis group and 27.3 ± 7.7% in the good prognosis group. The occurrence rate of high signal changes in MRI T2WI was 84.2% in the poor prognosis group and 41.3% in the good prognosis group. Poor prognosis was correlated with high occupying ratio and spinal cord high signal changes in MRI T2WI. In the patient with SCIWORA associated with C-OPLL, ROC curve of occupying ratio showed 30% as a predictor for the poor prognosis. Among the 92 patients with occupying ratio ≤ 30%, poor prognosis was observed in 5 cases (5.4%), whereas in the 72 cases with occupying ratio > 30%, poor prognosis was seen in 33 cases (45.8%). Postoperative AIS grade at final follow-up in occupying ratio > 30% group was significantly worse.

Conclusions

Patients suffering from SCIWORA with C-OPLL have poor prognosis when they have higher occupying ratio of ossification mass and spinal cord high signal changes in MRI T2WI. The cut-off value of occupying ratio for predicting the poor prognosis was 30% in patients with SCIWORA associated with C-OPLL.

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

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.