Neuropathic pain relief and altered brain networks after dorsal root entry zone microcoagulation in patients with spinal cord injury

Brain Communications, 2024 · DOI: https://doi.org/10.1093/braincomms/fcae411 · Published: November 21, 2024

Spinal Cord Injury Neurology Pain Management

Simple Explanation

This study explores a surgical treatment (DREZ microcoagulation) for severe neuropathic pain in individuals with spinal cord injuries (SCI). It examines how this surgery affects brain activity related to pain. The research compares brain scans of SCI patients with severe pain before and after surgery, as well as to those with low pain and healthy individuals to understand the changes in brain networks associated with pain relief. The findings suggest that DREZ microcoagulation alters brain networks involved in pain processing, especially those connected to the somatosensory cortex, limbic system, and prefrontal cortex, providing a potential route for pain management in SCI patients.

Study Duration

1+ year follow-up

Participants

8 persons with clinically complete SCI, group-matched low pain SCI, and healthy controls

Evidence Level

Not specified

Key Findings

1
DREZ microcoagulation resulted in short-term (12 days) and long-term (1+ year) pain relief for participants with SCI below-level neuropathic pain, especially when lesioning both cephalad and caudal to the injury.
2
The surgery normalized negative functional coupling between primary sensory and motor cortices to the hippocampus, amygdala, and medial prefrontal cortex.
3
DREZ hyperactivity corresponded to a non-classical SNS-mediated somatotopic map of DREZ below-level pain generators, indicating a different pain pathway.

Research Summary

This study investigated the effectiveness of dorsal root entry zone (DREZ) microcoagulation in relieving below-level neuropathic pain in patients with spinal cord injury (SCI). The research involved pre- and post-operative fMRI scans to assess changes in brain connectivity and activity following the surgical intervention, compared with low pain SCI patients and healthy controls. The results indicated significant pain relief and normalization of brain network connectivity, particularly within the somatosensory-limbic-prefrontal cortex, suggesting a novel pain pathway mediated by the sympathetic nervous system (SNS).

Practical Implications

Novel Pain Pathway

Identifies a non-classical SNS-mediated pain pathway, offering new targets for pain management.

Brain Network Normalization

Demonstrates that DREZ surgery can normalize dysfunctional brain connectivity patterns associated with chronic neuropathic pain.

Improved Quality of Life

Highlights the potential for DREZ microcoagulation to significantly improve the quality of life for SCI patients suffering from intractable neuropathic pain.

Study Limitations

1
Two participants had return of pain at 2 months post-op.
2
The lack of a surgical placebo control.
3
The possibility that below-level pain afferents may re-route across the spinal cord lesion via the sympathetic chain has long been discounted in the literature because of the inability of sympathetic blockade to relieve below-level neuropathic pain.

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