Difference of Dynamic Morphometric Changes Between in Patients with Ossification of Posterior Longitudinal Ligament and Patients with Cervical Spondylosis: Assessment by Cervical Dynamic Magnetic Resonance Imaging

Dynamic Flexion-Extension Magnetic Resonance Imaging of the Cervical Spine: An Evolutionary Tool for Diagnosis and Management of Cervical Spondylotic Myelopathy

Dynamic problems need dynamic solutions. High motility of the cervical spine causes a common age-related degenerative condition called cervical spondylotic myelopathy (CSM), manifested by neurological impairments. An accurate and reliable diagnosis of CSM is crucial for determining appropriate management strategies. Traditional static magnetic resonance imaging (MRI) has been the gold standard for imaging CSM; however, it may not fully capture dynamic changes during neck movement. Dynamic flexion-extension (DFE) MRI is an innovative imaging technique that allows for real-time visualization of cervical spine motion. This review article aims to scrutinize the role of DFE MRI in assessing CSM, its added value to clinical implementations, and its limitations. Finally, by addressing the knowledge gaps, this survey sheds light on the road ahead to incorporate DFE MRI into a standard version of the practice.

Contribution of dynamic cervical MRI to surgical planning for degenerative cervical myelopathy: Revision rate and clinical outcomes at 5 years' postoperative

INTRODUCTION

Cervical MRI is the gold standard for surgical planning of degenerative cervical myelopathy; however, the symptomatic postoperative recurrence rate is high in the medium and long terms (9.1% to 10.7%) and may bring into question the quality of the preoperative surgical plan. The objective of this study was to evaluate cervical spinal stenosis and intramedullary hyperintensity with dynamic cervical MRI to determine the recurrence rate and clinical improvement in a cohort of patients who had dynamic cervical MRI incorporated into their surgical plan.

METHODS

This was a prospective, single-center study. Upon enrolment and at each follow-up visit, patients completed the mJOA score, NDI, cervical pain on visual analog scale (VAS) and radicular pain on VAS. Every enrolled patient underwent dynamic cervical MRI (in neutral, flexion and extension positions). Five levels were measured in the three positions, resulting in 915 levels for analysis.

RESULTS

Sixty-one patients were included. Eighty-four levels had an intramedullary hyperintensity in neutral position, 93 in extension and 112 in flexion. The mean sagittal diameter varied the most at C4-C5, going from 7.13mm (SD 2.32) on average in neutral to 6.30mm (SD 2.22) in extension and 8.29mm (SD 2.10) in flexion, a variation of -12% and +16%, respectively. A Mühle grade≥2 was found in 134 levels in neutral position versus 189 in extension and 110 in flexion. None of the patients had worse neurological symptoms following the dynamic cervical MRI. The mean postoperative follow-up was 4.4 years (SD 0.88). Two patients (3.1%) required surgical revision because the implants had shifted. One patient developed symptomatic adjacent segment disease.

CONCLUSION

Preoperative surgical planning that incorporates dynamic cervical MRI before the surgical treatment of degenerative cervical myelopathy appears to be a safe and reliable method and one that helps reduce symptoms in the long term.

LEVEL OF EVIDENCE

IV.

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.

Influence of dynamic neck motion on the clinical usefulness of multi-positional MRI in cervical degenerative spondylosis

PURPOSE

The purpose of this study was to find out additional indications for multi-positional MRI in cervical degenerative spondylosis (CDS) patients.

MATERIAL AND METHODS

A total of 63 patients with cervical spondylotic myelopathy that underwent multi-positional MRI and X-ray were included. Muhle's grade, C2-7 angle, and C7 slope were measured. Patients were assigned to the stenosis group (Group S) when Muhle's grades were increased by more than two or maximum grade was reached. Other patients were assigned to the maintenance group (Group M). Receiver operating characteristic (ROC) analysis was performed. Statistical significance was accepted for p values of < 0.05.

RESULTS

A total of 24 patients were assigned to the S group and 39 patients to the M group. Mean C2-7 angle difference in extension (eC27A) between S and M groups was 10.97° (p = 0.002). The mean inter-group difference between C2-7 angle in extension and neutral positions (e-nC27A) was 14.39° (p = 0.000). Mean C7 slope difference in neutral position was  - 6.53° (p = 0.002). Based on areas under ROC curves (AUCs), e-nC27A, eC27A, and negative C7 slope had AUCs of 0.934 (95% CI 0.876-0.992), 0.752 (95% CI 0.624-0.880), and 0.720 (95% CI 0.588-0.851), respectively. The optimal cutoff value of e-nC27A was 15.4 degrees, which had a diagnostic accuracy of 88.9%.

CONCLUSION

Multi-positional MRI helps to find dynamic cord compressive lesion in CDS patients. The higher eC27A, e-nC27A values and smaller C7 slope were found to increase the likelihood of cervical dynamic stenosis. Among other factors, we recommend multi-positional MRI before surgery especially when a patient's e-nC27A is > 15.4 degrees.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Dynamic Cord Compression Causing Cervical Myelopathy

Due to the highly mobile nature of the cervical spine, and the fact that most magnetic resonance imagings (MRIs) and computed tomography scans are obtained only in one single position, dynamic cord compression can be an elusive diagnosis that is often missed and not well-understood. In this context, dynamic MRI (dMRI) has been utilized to improve the diagnostic accuracy of cervical stenosis. We performed a literature review on dynamic cord compression in the context of cervical spondylotic myelopathy (CSM), with particular emphasis on the role of dMRI. Cadaveric studies report that the spinal cord lengthens in flexion and the spinal canal dimension increases, whereas the spinal cord relaxes and shortens in extension and the spinal canal decreases. These changes may lead to biomechanical stress in the spinal cord with movement, especially in patients with critical cervical stenosis. The majority of the studies using dMRI in CSM reported that this imaging modality is more sensitive at detecting cervical cord compression compared to routine MRIs done in a neutral position, especially with the neck in extension. Dynamic MRI was also useful to diagnose dynamic cervical cord compression after laminectomies in patients with clinical deterioration without evident cord compression on neutral static MRI. Finally, dMRI is more sensitive in detecting stenosis in patients with CSM than in those with ossification of the posterior longitudinal ligament (OPLL), likely because OPLL patients often have a more limited range of motion than CSM patients. Thus, dMRI is a promising new tool that can help spine surgeons in diagnosing and treating CSM.