You are currently on the new version of our website. Access the old version .
JCMJournal of Clinical Medicine
  • Editorial
  • Open Access

22 July 2022

Degenerative Cervical Myelopathy and Spinal Cord Injury: Introduction to the Special Issue

,
and
1
Department of Neurosurgery, University of California, Davis, CA 95817, USA
2
Division of Neurosurgery, Geneva University Hospitals, 1205 Geneva, Switzerland
*
Author to whom correspondence should be addressed.
This article belongs to the Special Issue Management of Degenerative Cervical Myelopathy and Spinal Cord Injury
Damage to the spinal cord (SC) can arise from either traumatic or non-traumatic spinal cord injury (SCI). Non-traumatic forms of SCI include degenerative cervical myelopathy (DCM) in which spinal degeneration secondary to age-related degeneration of the discs, ligaments, and vertebrae of the cervical spine causes cord compression, resulting in varying degrees of neurological dysfunction. On the other hand, traumatic spinal cord injury (tSCI) is principally due to immediate mechanical insult resulting in sudden onset motor, sensory and autonomic dysfunction, and secondary injury mechanisms resulting from the resulting inflammation. Both DCM and tSCI share similar pathological and molecular characteristics including neuro-inflammation, axonal degeneration, and alpha-motor neuron degeneration and result in similar patterns of anterograde and retrograde remodeling of synaptic pathways [1,2]. MRI-based imaging studies have found similarities in the degeneration of the dorsal and lateral columns and in degrees of remote SC pathology [1,2]. In addition, patients with either DCM or non-myelopathic SC compression are predisposed to tSCI from even a minor trauma, as the compressed SC is more vulnerable to dynamic forces and kinking, particularly in hyperextension injuries; this type of tSCI is commonly termed ‘central cord syndrome’ and presents with quadriparesis that affects upper extremities more than lower extremities [3]. The relationship between DCM and tSCI is still being elucidated in the literature and could offer a means to study SCI by assessing the large population of individuals with DCM that frequently have stable or slowly progressive disease.
Both traumatic and non-traumatic SCI are anatomically and physiologically complex pathologies that present with variable symptoms and severity including numbness, impaired hand dexterity, weakness, unsteady gait, and sphincter dysfunction [1,2]. Traditionally, physician administered outcome measures such as mJOA and Nurick, and patient reported NDI, have been used to classify DCM severity, while tSCI studies typically report ASIA Impairment Scale (AIS) and the ISNCSCI, which includes high reliability and objective interpretation of findings. However, the ISNCSCI is not sensitive to subtle SC dysfunction such as hand incoordination or gait imbalance, which are subjectively captured by DCM outcome measures (e.g., mJOA) [4]. Both pathologies impair patients’ mobility, strength, and coordination, significantly affecting patients’ quality of life, resulting in a significant healthcare burden as the leading cause of SC dysfunction. Over the past few years, there has been increased research on clinical course, diagnosis, treatment threshold, and patient outcomes which have guided the establishment of treatment and diagnosis guidelines. However, there remains significant knowledge gaps, and, as a consequence, practice guidelines have been formed with limited strength of evidence, indicating a continued need for further investigation.
The present Special Issue is dedicated to presenting current research topics in DCM and SCI in an attempt to bridge gaps in knowledge for both of the two main forms of SCI. The issue consists of fourteen studies, of which the majority were on DCM, the more common pathology, while three studies focused on tSCI. This issue includes two narrative reviews, three systematic reviews and nine original research papers. Areas of research covered include image studies, predictive modeling, prognostic factors, and multiple systemic or narrative reviews on various aspects of these conditions. These articles include the contributions of a diverse group of researchers with various approaches to studying SCI coming from multiple countries, including Canada, Czech Republic, Germany, Poland, Switzerland, United Kingdom, and the United States.
The pathological impacts of DCM and tSCI are not limited to the SC; downstream and upstream neural pathways have been shown to significantly affect cortical volume with an increased connectivity within sensorimotor and pain related cortical regions which may affect patient perceived pain and symptom burden over time [5]. Oughourlian et al. [5] were one of the first to assess sex related differences in cerebral cortex changes, utilizing a vertex level linear model (n = 85). They found significant differences between male and female DCM patients, including significantly less grey matter volume (GMV) changes in females over a broader range of cortical areas compared to their male counterparts despite no differences between GMV volumetric differences amongst controls. These changes were also correlated with mJOA and in the future could be used to further understand role of sex-hormones and prognostic factors in pathogenesis of DCM. Wolf et al. [6] also found gender related differences in SC motion patterns amongst men with stenosis at the C5/C6 or C6/C7 levels and no relationship between cervical joint motion to severity of the stenosis indicating the need for further assessment of gender differences in pathological features of DCM. On assessment of outcome measures for DCM, Kadanka et al. [7], showed that the standardized 10 m walk/run test can assess motor and balance abnormalities in both classic DCM patients and non-myelopathic degenerative cervical cord compression (NMDCC) patients, which has a 40% prevalence in 60+ age groups in European/American subpopulation. This was the first study assessing such changes in NMDCC patients and the 10 m walk/run test closely correlated with mJOA, which could allow for early detection of DCM before permanent neurodegeneration occurs.
In terms of surgical prognostic factors, Wilson et al. [8] challenged the previously used parameter of age and found that frailty as scored by the MFI-5 has the largest effect size and is more likely to predict peri-operative adverse events including mortality, readmission or re-operation, length of hospital stay, and recovery location. This study utilized information from over 41,000 DCM patients who underwent a variety of surgical treatments with the majority (70.8%) of single or two-level pathology providing strong evidence to incorporate frailty tests such as MFI-5 in clinical practice instead of less reliable measures such as age.
Image-oriented research by Jentzsch et al. [9] assessed potential surgical prognostic factors found on MRI for prospectively collected data for 459 patients who had prior SCI and found that SC signal change is a significant predictor (109%) of adverse events including neurologic impairment and decreased ambulation initially and at follow-up one year later. These findings are in agreement with the 14 small (n < 100) prospective studies summarized by Jentzsch et al. in the paper which found further negative prognostic association between pre-operative SC signal change and post-operative clinical outcomes. The implications of this study are significant and highlight the need for further research on other imaging based prognostic factors through large prospective, long-term, and confounder-controlled studies.
Building on this concept, Ost et al. [10] explored the predictive modeling of MR imaging of 328 DCM patients and found that metrics such as cross-sectional area, eccentricity, and solidity were not correlated with mJOA disease severity, and with the variations appearing to be due to patient-specific parameters. This highlights the complexity of DCM and the need for further integrated approaches to modeling efforts. Imaging data is one of many core tenets to management and surgical decision making for DCM, however, assessing severity and progression continues to rely on physical and neurological measures. The authors additionally conclude that future efforts that utilize more complex models, normalize metrics per-patient, and assess healthy control variations could overcome the limitations of the current model used by Ost et al.
Beyond conservative management and close monitoring, surgical decompression is the main-stay treatment for DCM and a variety of surgical approaches and interventions have been utilized. Appropriate selection of surgical intervention is based on patient characteristics, disease pathology, and risk factors. Sommaruga et al. [11] compared the surgical outcomes including Bazaz dysphagia score, Nurick grade, and hospital stay between stand-alone zero-profile implants and more traditionally used cervical plating in anterior cervical discectomy and fusion. The study, consisting of 116 patients, found a shorter hospital course and operation time for stand-alone implants; however, neurologic and dysphagia outcomes were similar across both groups. This study adds to the growing literature on differences between various anterior surgical treatments.
On a similar note, Wincek et al. [12] studied repetitive transcranial magnetic stimulation (rTMS) and kinesiotherapy across an average of 5 months in 26 patients with incomplete SCI and found significant improvements including reduced upper extremity spasticity, motor unit recruitment and efferent neural transmission. These findings are a promising therapeutic method for enhancing outcomes in patients with incomplete SCI and addressing neurodegenerative changes in DCM. However, this area remains in its infancy.
Many patients with DCM present with uncommon symptoms and, due to the older age and complex anatomy of DCM involving both SC and brain, present with a variety of unexplained symptoms. Previous literature included cervical vertigo as a symptom which was discussed by Kadanka et al. [13] through a patient case series (n = 38) on vertigo in DCM patients which found alternate etiology, indicating the importance of appropriately assessing the symptoms that may occur in DCM and considering alternate diagnoses.
This Special Issue also includes three systematic reviews. The first of these, by Ghaffari-Rafi et al. [14], assessed the role and impact of obtaining an MRI in acute SCI on clinical outcomes and decision making. Of the 32 studies included, MR imaging frequently identified pathologies such as spinal cord compression, ligamentous injury, and epidural hematoma that altered the acute management of SCI, including the need for surgery, timing of surgery, and the surgical approach (anterior vs. posterior). MRI also showed good to excellent diagnostic accuracy for various types of ligamentous injury and epidural hematoma, but poor accuracy for fracture detection. This systematic review and meta-analysis strengthens the argument that obtaining MRI is important in cases of acute SCI, while highlighting knowledge gaps on cost-effectiveness and impact on outcomes.
Yang et al. [15] provided a comprehensive systematic review of posterior approaches to multi-level DCM, highlighting that the variation of study designs, outcomes, and limited direct comparison of techniques has led to lack of high-level evidence to guide surgical approach to management of DCM. Amongst the limited studies that directly compared surgical techniques, there were many contradictory findings, emphasizing the need for future RCT or prospective multi-center studies, which are currently underway in the UK with POLYFIX-DCM trial (Posterior LaminectomY and FIXation for DCM).
Lannon et al. [16] summarized the clinical presentation, treatment, and natural history of DCM in their manuscript. Of note, there are no pathognomonic signs for DCM, but rather a constellation of symptoms, physical exam findings, and imaging features that all typically have a slowly progressive course. Imaging findings classically include the absence of a cerebrospinal fluid signal on T2-weighted images, T2 signal hyperintensity, and rarely “snake eyes appearance”, with symmetric circular foci in the gray matter. Additionally, DCM tends to involve progressive neurological deterioration amongst 20% to 62% of patients within 3–6 years. On the other hand, Tu et al. [17] comprehensively discussed the physical exam sensitivity and specificity, commonly used radiographic measures, and T1 vs. T2 MRI findings. Tu et al. also comprehensively summarized the associated genetic polymorphisms, impact of microbiome and molecular features involved in the pathogenesis of disc degeneration, SC dysfunction, axonal injury, and the role and impact of various cell lines on disease course. This study highlighted multiple molecular and micro-structural knowledge gaps, as well as the limited methods to assess degenerative cervical myelopathy appropriately and extensively.
Recognizing the limitations and variability of current outcome measures utilized to study DCM, Soufi et al. [4], assessed the number, quality, and variety of outcome measures currently used in the literature through a systematic review on 148 studies. A total of 39% percent of studies utilized single outcome measures with an average of 2.36 outcome measures used in the studies, with no studies specifically assessing key functions including dorsal column sensory pathway or respiratory, bowel, and sexual function. Objective physical testing of neurological function was rarely utilized, with questionnaires representing 92% (320/349) of all outcome measures utilized, emphasizing the need for a concerted effort in more accurately quantifying neurological dysfunction in DCM, for the purpose of improving diagnosis, measuring severity, and monitoring patients for deterioration.
It was the intention of this Special Issue to address a wide range of topics regarding DCM and SCI. This project was pursued by the Journal of Clinical Medicine Editorial Board with the hope of contributing new research to help tackle these two prevalent and disabling clinical disorders. We would like to thank the various authors and peer-reviewers for helping to amass this unique body of work (Table 1).
Table 1. Summary of published papers in this Special Issue.

Author Contributions

Conceptualization, A.R.M. and A.N.; data curation, K.S.; Writing—original draft preparation, K.S.; writing—review and editing, A.R.M., A.N. and K.S.; supervision, A.R.M. and A.N. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. David, G.; Vallotton, K.; Hupp, M.; Curt, A.; Freund, P.; Seif, M. Extent of cord pathology in the lumbosacral enlargement in non-traumatic versus traumatic spinal cord injury. J. Neurotrauma 2022, 39, 639–650. [Google Scholar] [CrossRef] [PubMed]
  2. David, G.; Mohammadi, S.; Martin, A.R.; Cohen-Adad, J.; Weiskopf, N.; Thompson, A.; Freund, P. Traumatic and nontraumatic spinal cord injury: Pathological insights from neuroimaging. Nat. Rev. Neurol. 2019, 15, 718–731. [Google Scholar] [CrossRef] [PubMed]
  3. Seif, M.; David, G.; Huber, E.; Vallotton, K.; Curt, A.; Freund, P. Cervical cord neurodegeneration in traumatic and non-traumatic spinal cord injury. J. Neurotrauma 2020, 37, 860–867. [Google Scholar] [CrossRef] [PubMed]
  4. Soufi, K.H.; Perez, T.M.; Umoye, A.O.; Yang, J.; Burgos, M.; Martin, A.R. How Is Spinal Cord Function Measured in Degenerative Cervical Myelopathy? A Systematic Review. J. Clin. Med. 2022, 11, 1441. [Google Scholar] [CrossRef] [PubMed]
  5. Oughourlian, T.C.; Wang, C.; Salamon, N.; Holly, L.T.; Ellingson, B.M. Sex-Dependent Cortical Volume Changes in Patients with Degenerative Cervical Myelopathy. J. Clin. Med. 2021, 10, 3965. [Google Scholar] [CrossRef] [PubMed]
  6. Wolf, K.; Reisert, M.; Beltrán, S.F.; Klingler, J.-H.; Hubbe, U.; Krafft, A.J.; Kremers, N.; Egger, K.; Hohenhaus, M. Spinal Cord Motion in Degenerative Cervical Myelopathy: The Level of the Stenotic Segment and Gender Cause Altered Pathodynamics. J. Clin. Med. 2021, 10, 3788. [Google Scholar] [CrossRef] [PubMed]
  7. Kadanka Jr, Z.; Kadanka Sr, Z.; Skutil, T.; Vlckova, E.; Bednarik, J. Walk and Run Test in Patients with Degenerative Compression of the Cervical Spinal Cord. J. Clin. Med. 2021, 10, 927. [Google Scholar] [CrossRef] [PubMed]
  8. Wilson, J.; Badhiwala, J.; Moghaddamjou, A.; Yee, A.; Wilson, J.; Fehlings, M. Frailty is a better predictor than age of mortality and perioperative complications after surgery for degenerative cervical myelopathy: An analysis of 41,369 patients from the nsqip database 2010–2018. J. Clin. Med. 2020, 9, 3491. [Google Scholar] [CrossRef] [PubMed]
  9. Jentzsch, T.; Cadotte, D.W.; Wilson, J.R.; Jiang, F.; Badhiwala, J.H.; Akbar, M.A.; Rocos, B.; Grossman, R.G.; Aarabi, B.; Harrop, J.S.; et al. 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. J. Clin. Med. 2021, 10, 4778. [Google Scholar] [CrossRef] [PubMed]
  10. Ost, K.; Jacobs, W.; Evaniew, N.; Cohen-Adad, J.; Anderson, D.; Cadotte, D. Spinal cord morphology in degenerative cervical myelopathy patients; assessing key morphological characteristics using machine vision tools. J. Clin. Med. 2021, 10, 892. [Google Scholar] [CrossRef] [PubMed]
  11. Sommaruga, S.; Camara-Quintana, J.; Patel, K.; Nouri, A.; Tessitore, E.; Molliqaj, G.; Panchagnula, S.; Robinson, M.; Virojanapa, J.; Sun, X.; et al. Clinical Outcomes between Stand-Alone Zero-Profile Spacers and Cervical Plate with Cage Fixation for Anterior Cervical Discectomy and Fusion: A Retrospective Analysis of 166 Patients. J. Clin. Med. 2021, 10, 3076. [Google Scholar] [CrossRef] [PubMed]
  12. Wincek, A.; Huber, J.; Leszczyńska, K.; Fortuna, W.; Okurowski, S.; Chmielak, K.; Tabakow, P. The long-term effect of treatment using the transcranial magnetic stimulation rTMS in patients after incomplete cervical or thoracic spinal cord injury. J. Clin. Med. 2021, 10, 2975. [Google Scholar] [CrossRef] [PubMed]
  13. Kadanka, Z.; Kadanka, Z.; Jura, R.; Bednarik, J. Vertigo in patients with degenerative cervical myelopathy. J. Clin. Med. 2021, 10, 2496. [Google Scholar] [CrossRef] [PubMed]
  14. Ghaffari-Rafi, A.; Peterson, C.; Leon-Rojas, J.E.; Tadokoro, N.; Lange, S.F.; Kaushal, M.; Tetreault, L.; Fehlings, M.G.; Martin, A.R. The Role of Magnetic Resonance Imaging to Inform Clinical Decision-Making in Acute Spinal Cord Injury: A Systematic Review and Meta-Analysis. J. Clin. Med. 2021, 10, 4948. [Google Scholar] [CrossRef]
  15. Yang, X.; Gharooni, A.A.; Dhillon, R.S.; Goacher, E.; Dyson, E.W.; Mowforth, O.; Budu, A.; Wynne-Jones, G.; Francis, J.; Trivedi, R.; et al. The relative merits of posterior surgical treatments for multi-level degenerative cervical myelopathy remain uncertain: Findings from a systematic review. J. Clin. Med. 2021, 10, 3653. [Google Scholar] [CrossRef]
  16. Lannon, M.; Kachur, E. Degenerative Cervical myelopathy: Clinical presentation, assessment, and natural history. J. Clin. Med. 2021, 10, 3626. [Google Scholar] [CrossRef]
  17. Tu, J.; Castillo, J.V.; Das, A.; Diwan, A. Degenerative cervical myelopathy: Insights into its pathobiology and molecular mechanisms. J. Clin. Med. 2021, 10, 1214. [Google Scholar] [CrossRef]
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Article Metrics

Citations

Article Access Statistics

Multiple requests from the same IP address are counted as one view.