Cerebrospinal Fluid Dynamics and Subarachnoid Space Occlusion Following Traumatic Spinal Cord Injury in the Pig: An Investigation Using Magnetic Resonance Imaging
Study on Cerebrospinal Fluid Dynamics Following Traumatic Spinal Cord Injury in a Porcine Model
Background
Traumatic Spinal Cord Injury (SCI) is a severe neurological disorder that often leads to permanent neurological dysfunction. Despite years of efforts by scientists to develop treatments, progress has been limited due to the complex pathophysiology and heterogeneity of the injury. Following SCI, spinal cord swelling and occlusion of the subarachnoid space (SAS) are common pathological phenomena, which may lead to spinal cord compression and reduced blood perfusion. Timely surgical decompression is considered crucial for improving neurological recovery, but not all patients achieve complete restoration of SAS patency through surgery. Therefore, monitoring the effectiveness of decompression and pathological changes after SCI has become an important issue in clinical management.
Changes in cerebrospinal fluid (CSF) dynamics may be closely related to the pathological processes following SCI. In healthy states, pulsatile CSF flow is regulated by the cardiovascular and respiratory systems, but after SCI, this flow may be altered. Using magnetic resonance imaging (MRI) techniques, particularly phase-contrast MRI (PC-MRI), the characteristics of CSF flow can be monitored non-invasively, providing new insights into the pathological changes following SCI.
Source of the Paper
This paper was authored by Madeleine Amy Bessen and colleagues from multiple research institutions at the University of Adelaide, Australia, including the Adelaide Spinal Research Group and the Translational Neuropathology Laboratory. The paper was published in 2025 in the journal Fluids and Barriers of the CNS under the title Fluids and Barriers of the CNS (2025) 22:6. The study was funded by a basic research grant from the North American Spine Society and supported by the Australian Government Research Training Program.
Research Process
1. Animal Model and Experimental Design
The study used 10 female domestic pigs (weighing 22-29 kg), randomly divided into two groups: one group received a 10 cm weight-drop injury (n=5), and the other received a 20 cm injury (n=5). All animals underwent MRI scans before injury and on days 3, 7, and 14 post-injury. The main objectives of the study were: (1) to characterize the extent of SAS occlusion; and (2) to investigate changes in CSF dynamics over 14 days following SCI.
2. Induction of Spinal Cord Injury and Postoperative Care
Spinal cord injury was induced at the T10 thoracic level using a weight-drop apparatus. After injury, the animals received 24-hour continuous care, including analgesia and antibiotic treatment. On days 8 and 13 post-injury, researchers assessed hindlimb motor function using the Porcine Thoracic Behaviour Scale (PTIBS).
3. MRI Scanning and Data Analysis
MRI scans included T2-weighted imaging and phase-contrast MRI (PC-MRI). T2-weighted imaging was used to measure the length and cross-sectional area of SAS occlusion, while PC-MRI was used to measure peak CSF flow velocity and flow timing. Data analysis employed linear mixed-effects models (LMM) to assess the effects of injury group and time point on SAS occlusion and CSF dynamics.
Key Findings
1. Changes in Subarachnoid Space Occlusion
The study found that the length of SAS occlusion in the 20 cm injury group was significantly longer than in the 10 cm group on day 3 post-injury. Over time, the occlusion length gradually decreased, and the cross-sectional area increased. This indicates that spinal cord swelling gradually subsided after injury, and SAS patency was partially restored.
2. Changes in CSF Dynamics
On day 3 post-injury, peak CSF flow velocity significantly decreased at all spinal levels, particularly at T8/T9, where pulsatile CSF flow almost disappeared. Over time, peak CSF flow velocity gradually recovered, and by day 14 post-injury, CSF flow characteristics approached baseline levels. Additionally, the study found that changes in peak CSF flow velocity and timing were closely related to the extent of SAS occlusion.
3. Motor Function and Histological Analysis
Assessed using PTIBS, the hindlimb motor function in the 20 cm injury group was significantly worse than in the 10 cm group. Histological analysis revealed that the 20 cm injury group had a larger lesion area and more extensive damage.
Conclusions and Significance
This study systematically investigated changes in SAS occlusion and CSF dynamics following traumatic SCI in a porcine model. The findings indicate that the extent of SAS occlusion after SCI is closely related to CSF flow characteristics, with pulsatile CSF flow significantly decreasing post-injury but gradually recovering over time. These findings provide new insights into the pathophysiological mechanisms of SCI and offer a potential non-invasive method for clinically monitoring decompression effectiveness and CSF dynamics.
Research Highlights
- Innovative Methodology: The study is the first to systematically investigate changes in SAS occlusion and CSF dynamics following SCI in a porcine model using a combination of T2-weighted MRI and PC-MRI.
- Clinical Significance: The results suggest that PC-MRI can serve as a non-invasive tool for monitoring CSF dynamics after SCI, providing important references for clinical treatment.
- Pathological Mechanism Insights: The study reveals that pulsatile CSF flow is closely related to the extent of SAS occlusion, offering new perspectives for understanding the pathological mechanisms of SCI.
Additional Valuable Information
The study also found that although the SAS was almost completely occluded on day 3 post-injury, CSF flow characteristics gradually recovered by day 14, indicating that spinal cord swelling and SAS occlusion are reversible. This finding provides new directions for future treatment strategies, such as improving CSF flow to promote spinal cord functional recovery.
This research not only provides new insights into the pathophysiological mechanisms of traumatic SCI but also offers potential non-invasive methods for clinical monitoring and treatment.