**1. Introduction**

It is necessary to fully understand the latest definition of pain, and it is well implied that this subject has imposed several challenges toward pain practitioners, requiring some adjustments over the years. The revised International Association for the Study of Pain recommended that the concept of pain should be revised to "An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage." It is well known that this definition has suffered changes over the years because of the complexity of this experience where it can differ broadly in intensity, quality, and duration and has varied pathophysiology mechanisms and implications [1–4].

Pain as an aporia. The approach toward the treatment of pain needs to be multidisciplinary, that is why all the patients with persistent pain invite a clinical judgment of psychosocial susceptibility. The pain experience phenomena are very complex to

understand; in these recent years, we still practice a linear (biomedical) approach where we do not find success in terms of treatment; this construct goes beyond biomedical approaches. We as doctors need to accept that there are various cases where the solution is beyond our expertise and very difficult to comprehend. That is why currently the concept of pain constitutes an aporia (paradox), but as pain physicians we have the ethical obligation to engage this disease to benefit the patient that is experiencing pain [3–5].

Persistent pain as a disease implicates changes that include modified sensory feedback within the somatosensory system. It has been documented that different anatomical restructuring in nociceptive integration and adaptations in nociceptive primary afferents and perception conduits are present in persistent pain situations. This pain state involves a biopsychosocial model where the biological aspect is not always the answer; it is well described that pain states defined as "functional" are expressed, and there is no evidence that justifies this pathology, only psychological and environmental causes. There are other complex cases known as nociplastic pain; in this situation, there is no clear evidence of tissue harm causing the triggering of peripheral nociceptors or sign for disease or alteration of the somatosensory system responsible of the pain state [3, 4].

The proposition made by these authors regarding this construct brings up to mind the concept of biopsychosocial framework, where we can talk about the body-mind dualism proposed by Rene Descartes. It is very difficult to define pain, we as doctors try always to rule out potential biological causes that provoke pain, forgetting that sometimes there is a biopsychosocial framework responsible of this incident [2, 3].

Anesthesiologists play an important role in preventing this pathology, and they have all the tools and knowledge necessary to avoid this type of pain. Chronic postoperative pain (CPOP) is known as a particular disorder that not only associated with a specific nerve damage or manifestation of a unique inflammatory response but also associated with a mixture of both [3].
