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Thoracic Spinal Cord Hemisection Surgery and Open-Field Locomotor Assessment in the Rat
Published on: June 26, 2019
Longitudinal motor system changes from acute to chronic spinal cord injury
Tim M Emmenegger1, Dario Pfyffer1,2, Armin Curt1
1Spinal Cord Injury Centre, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
Background And Purpose:
In acute spinal cord injury (SCI), magnetic resonance imaging (MRI) reveals tissue bridges and neurodegeneration for 2 years. This 5-year study aims to track initial lesion changes, subsequent neurodegeneration, and their impact on recovery.
Methods:
This prospective longitudinal study enrolled acute SCI patients and healthy controls who were assessed clinically-and by MRI-regularly from 3 days postinjury up to 60 months. We employed histologically cross-validated quantitative MRI sequences sensitive to volume, myelin, and iron changes, thereby reflecting indirectly processes of neurodegeneration and neuroinflammation. General linear models tracked lesion and remote changes in volume, myelin- and iron-sensitive magnetic resonance indices over 5 years. Associations between lesion, degeneration, and recovery (using the Spinal Cord Independence Measure [SCIM] questionnaire and the International Standards for Neurological Classification of Spinal Cord Injury total motor score) were assessed.
Results:
Patients' motor scores improved by an average of 12.86 (95% confidence interval [CI] = 6.70-19.00) points, and SCIM by 26.08 (95% CI = 17.00-35.20) points. Within 3-28 days post-SCI, lesion size decreased by more than two-thirds (3 days: 302.52 ± 185.80 mm2 , 28 days: 76.77 ± 88.62 mm2 ), revealing tissue bridges. Cervical cord and corticospinal tract volumes transiently increased in SCI patients by 5% and 3%, respectively, accompanied by cervical myelin decreases and iron increases. Over time, progressive atrophy was observed in both regions, which was linked to early lesion dynamics. Tissue bridges, reduced swelling, and myelin content decreases were predictive of long-term motor score recovery and improved SCIM score.
Conclusions:
Studying acute changes and their impact on longer follow-up provides insights into SCI trajectory, highlighting the importance of acute intervention while indicating the potential to influence outcomes in the later stages.
Insights
Spinal cord injury (SCI) recovery is linked to early lesion changes and neurodegeneration. Tracking these changes over 5 years reveals tissue bridges and myelin loss predict better motor and functional outcomes.
Area of Science:
- Neuroscience
- Radiology
- Clinical Neurology
Background:
- Acute spinal cord injury (SCI) involves complex tissue changes and neurodegeneration detectable by MRI for up to two years.
- Longitudinal tracking of these changes is crucial for understanding recovery trajectories.
Purpose of the Study:
- To longitudinally track initial lesion dynamics and subsequent neurodegeneration in acute SCI patients over five years.
- To investigate the impact of these changes on patient recovery and functional outcomes.
Main Methods:
- A prospective longitudinal study involving acute SCI patients and healthy controls, with regular clinical and MRI assessments up to 60 months post-injury.
- Quantitative MRI sequences sensitive to volume, myelin, and iron changes were used to indirectly reflect neurodegeneration and neuroinflammation.
- General linear models analyzed lesion and remote changes, and associations with recovery metrics (Spinal Cord Independence Measure [SCIM] and International Standards for Neurological Classification of Spinal Cord Injury total motor score).
Main Results:
- Patients showed significant improvements in motor scores (12.86 points) and SCIM scores (26.08 points) over the study period.
- Lesion size decreased significantly within the first month post-SCI, revealing tissue bridges.
- Transient increases in cervical cord and corticospinal tract volumes were observed, accompanied by myelin decreases and iron increases, followed by progressive atrophy linked to early lesion dynamics.
Conclusions:
- Early changes in spinal cord injury (SCI) lesions, including tissue bridge formation and myelin reduction, are significant predictors of long-term motor and functional recovery.
- Understanding the acute SCI trajectory and its impact on later stages highlights the potential for interventions to influence outcomes.
