When Healing Isn’t Enough

A common assumption in both clinical practice and everyday life is that pain should resolve once damaged tissues have healed. In many situations, this is precisely what occurs. Biological repair is followed by progressive restoration of function, and pain gradually subsides as healing is completed. Persistent pain presents a different clinical picture. Individuals may continue to experience pain despite the absence of ongoing tissue injury, while others recover uneventfully following comparable injuries. These observations have encouraged researchers to investigate mechanisms extending beyond peripheral tissues alone and to consider how the nervous system itself may adapt during persistent pain.¹ Recognizing this distinction has fundamentally broadened contemporary pain neuroscience and shifted attention toward understanding not only tissue pathology but also the physiology of the nervous system responsible for interpreting nociceptive information.

Tissue Healing and Persistent Pain Biological tissues possess remarkable capacity for repair. Following injury, inflammation, cellular proliferation, and tissue remodelling generally occur according to predictable biological timeframes that vary among different tissue types. Clinical recovery, however, does not always parallel tissue healing. Numerous investigations have demonstrated that pain intensity often correlates poorly with structural findings and that symptoms may persist well beyond the expected period of biological repair.¹² These observations do not diminish the importance of tissue pathology; rather, they suggest that additional physiological processes may contribute to the persistence of pain after healing has occurred. This distinction represents an important principle in contemporary pain science: healing refers to the restoration of tissues, whereas recovery encompasses restoration of the individual as a whole. Central Sensitization: A Landmark Concept Among the landmark publications that transformed pain neuroscience was the review by Woolf (2011)¹, which synthesized decades of experimental research describing central sensitization as “an amplification of neural signalling within the central nervous system that elicits pain hypersensitivity.” The significance of this work extended well beyond providing a definition. Woolf’s review encouraged clinicians and researchers to consider that persistent pain might, in some circumstances, reflect alterations in central nervous system processing rather than ongoing tissue damage alone. The concept provided a physiological framework for understanding how changes within the nervous system could contribute to heightened pain sensitivity despite resolution of the original injury. The influence of this publication on both research and clinical practice cannot be overstated. It fundamentally broadened scientific thinking and stimulated an extensive body of investigation into the neurobiology of persistent pain.

Recent literature has continued to refine the interpretation of central sensitization while reinforcing the importance of distinguishing experimentally demonstrated mechanisms from broader clinical constructs. Contemporary reviews emphasize that central sensitization describes a specific neurophysiological phenomenon characterized by increased responsiveness of central nociceptive neurons rather than a diagnosis applicable to every individual with persistent pain.³⁻⁵ At the same time, advances in network neuroscience and systems biology have expanded understanding of persistent pain beyond isolated neuronal excitability. Current models increasingly recognize interactions among descending modulation, neuroimmune signalling, predictive processing, cortical network reorganization, autonomic regulation, and psychosocial influences as contributors to the complexity of persistent pain. These developments do not replace the concept of central sensitization; rather, they place it within a broader systems-based understanding of nervous system adaptation. Collectively, the contemporary literature reinforces one of the central themes of this paper: persistent pain should neither be explained solely by tissue pathology nor attributed exclusively to a single neurophysiological mechanism. Instead, it is best understood as the product of dynamic interactions occurring within an adaptive nervous system.

One of the most important lessons emerging from contemporary pain neuroscience is that healing and recovery should not automatically be regarded as synonymous. Tissue healing represents one component of recovery, but it does not necessarily account for the complex physiological adaptations that may occur within the nervous system during persistent pain. Equally important is the recognition that scientific concepts continue to evolve. Central sensitization remains one of the most influential frameworks in pain neuroscience, yet ongoing research has encouraged greater precision regarding its definition, underlying mechanisms, and clinical application. Contemporary investigators increasingly distinguish experimentally demonstrated neurophysiological phenomena from broader clinical pain presentations, emphasizing that central sensitization should be interpreted as a specific physiological construct rather than a universal explanation for all persistent pain conditions. These developments should not be viewed as contradictions of earlier work. Rather, they reflect the normal progression of scientific inquiry, where landmark concepts are continually refined as new evidence emerges. For clinicians, the practical message remains unchanged: when pain persists beyond the expected period of tissue healing, it is appropriate to broaden the scope of investigation. Questions relating to nervous system function, sleep, metabolic health, inflammation, movement, psychological stress, and overall physiological resilience become essential components of comprehensive clinical reasoning.