Mixed Pain: Toward a Consensus Definition and a Mechanism-Based Framework

Area of Science:

• Pain research and management
• Clinical pain classification

Background:

• Clinicians and researchers have historically struggled to classify pain conditions lacking clear mechanistic definitions.
• Many common pain disorders, such as chronic low back pain, cancer pain, and osteoarthritis, exhibit overlapping mechanisms, often termed 'mixed pain'.
• The absence of a unified definition for mixed pain has created ambiguity in research and clinical practice.

Purpose of the Study:

• To establish an internationally unified consensus definition for mixed pain.
• To address inconsistencies in pain terminology and mechanistic classification.
• To provide a framework for improved diagnosis and treatment of complex pain conditions.

Main Methods:

• An international consensus process involving leading global experts.
• Development of a definition for mixed pain based on overlapping mechanistic pain descriptors.

Main Results:

• Mixed pain is now defined as pain associated with a lesion, disease, or disorder resulting in an overlap of at least two mechanistic pain descriptors (nociceptive, neuropathic, or nociplastic).
• This definition provides conceptual clarity, moving from ambiguity to consensus.

Conclusions:

• The new definition of mixed pain facilitates alignment of research, refinement of diagnosis, and design of mechanism-based therapies.
• It establishes a practical foundation for future research, validation, and clinical application in complex pain management.
• This consensus transforms mixed pain into a potential framework within modern pain taxonomy, promoting individualized treatment approaches.