Botulinum Toxin as Targeted Neuromodulation in Complex Regional Pain Syndrome: An Anatomy-Informed Mechanistic Review

Area of Science:

• Neurology
• Pain Medicine
• Pharmacology

Background:

• Complex regional pain syndrome (CRPS) is a debilitating chronic pain condition with complex neuroplasticity.
• The clinical utility of botulinum toxin for CRPS is debated due to inconsistent study outcomes.

Purpose of the Study:

• To reconcile conflicting findings on botulinum toxin efficacy in CRPS.
• To propose an anatomy-informed framework for botulinum toxin application in CRPS.

Main Methods:

• Synthesis of mechanistic, translational, and clinical evidence.
• Integration of experimental data, randomized trials, and case-based evidence.
• Development of an anatomy-informed, route-specific neuromodulation framework.

Main Results:

• Inconsistent outcomes may stem from varied anatomical targeting and administration routes.
• Direct delivery to sympathetic nervous system and proximal somatic afferents shows more consistent therapeutic signals.
• Superficial or non-specific delivery methods result in more variable responses.

Conclusions:

• Botulinum toxin efficacy in CRPS is likely dependent on precise anatomical targeting.
• An anatomy-informed framework can guide rational trial design and clinical application of botulinum toxin.
• Future research should focus on phenotype-aligned, targeted delivery strategies for CRPS treatment.