It's tough to make predictions, especially about the future.
– Yogi Berra
The definition of pain has changed – literally. In 1979, the International Association for the Study of Pain (IASP) published this definition for pain: “An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.”1 Recognizing that pain can be a symptom or a disease itself, the IASP refined the pain classification model to include chronic primary pain.2 In 2020, the IASP further revised the definition of pain as follows: “An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage.”1 Input from IASP members and the public that factored into this new definition of pain highlighted several important themes. The definition of pain should be simple and practical, emphasize the personal nature of the pain experience, and incorporate the biopsychosocial model of pain.1 Therefore, while seemingly minor, the amendments by insertion and deletion emphasize that pain is an individual experience and that perception is reality.
The opioid epidemic has brought significant attention to issues in contemporary pain medicine.3 Treatment of opioid use disorder is challenging, and since the onset of the COVID-19 pandemic the magnitude of the challenges has become more apparent.4 While there are many factors that contributed to the overprescribing of opioids, including the “fifth vital sign” campaign and misinformation,5,6 the current crisis provides an opportunity to reevaluate the state of pain management in the U.S. The publication of Centers for Disease Control and Prevention (CDC) guidelines7, the Pain Management Best Practices Inter-Agency Task Force report,8 and recognition of surgery as a risk factor for the development of chronic opioid use,9 has caused the medical community to respond in recent years with opioid prescribing recommendations and safety initiatives10-12 and an emphasis on multimodality as the pathway to better pain management.13
The acceptance of pain as a potentially chronic condition defined at the level of the individual is also driving the field of pain medicine toward increased personalization. In addition, subspecialty areas in acute and transitional pain to complement the established field of chronic pain have emerged in recent years to fill existing gaps and provide comprehensive care.14,15 In looking ahead, we wish to highlight three priority areas for improvement: prediction, coordination, and implementation.
Our ability to deliver personalized pain medicine is hindered by our inability to predict which patients will go on to develop chronic pain. There has been significant scientific progress in understanding the mechanisms of pain using a biopsychosocial model and the transition from acute to chronic pain.16 Generally, these mechanisms involve nociceptive, inflammatory, and neuropathic pain leading to both peripheral and central sensitization.17 Certain surgeries such as limb amputation and thoracotomy have been associated with a greater incidence of persistent postsurgical pain (PPSP) that goes on to become a chronic pain condition.18 The impact of genetics on pain and its treatment is an ongoing field of research. In the case of PPSP, the combination of certain gene polymorphisms and phenotypic factors has been associated with an increased risk.17,19-21 Additional opportunities related to a better understanding of genetics include evaluating the metabolism and action of opioids,22 risk of substance use disorder,3 and potentially advanced interventional therapies for common chronic diseases such as intervertebral disc pathologies.24 We are also learning that treatment decisions related to pain management may have previously unrecognized and unanticipated long-term consequences. For example, there is growing concern that chronic opioid use may be associated with an increased risk of cancer recurrence and decreased survival in some patients.25
Many chronic pain syndromes start in response to systemic disease, chronic health conditions, non-surgical injury, chemotherapy, and other conditions, though as with PPSP, not all patients with the same conditions develop the same chronic pain conditions. The ability to leverage the wealth of clinical data from electronic health records and imaging studies has not yet been fully realized, and there is good reason to believe that application of these data in the form of artificial or augmented intelligence (AI) may allow predictions that will improve pain prevention as well as the diagnosis and treatment of pain.26,27
While the concept of acute pain services has matured with support from enhanced surgical recovery programs,28,29 a critical gap in pain care has been exposed between hospital discharge and the return to primary care.30 The use of a transitional pain service (TPS) for post-discharge follow-up and preoperative preparation of complex patients, such as those with chronic pain or opioid use, may facilitate a more coordinated approach to postoperative opioid tapering and subacute pain management and is consistent with the Perioperative Surgical Home model of care.29 Given that chronic pain costs over $600 billion per year, the need to improve pain care delivery and outcomes is unarguable. Improved predictive ability through AI may facilitate appropriate selection of TPS patients and interventions34 and the early application of effective pain therapies to assist in chronic pain prevention and treatment and aid in either avoiding opioids altogether or opioid cessation.35 In the setting of chronic pain, coordination of care and timely access to the full range of treatments to facilitate recovery are often lacking. This not only reduces treatment success but ultimately costs society on many different fronts.
There are many reasons why knowledge translation fails and clinical practice remains unchanged despite new evidence and guidelines.36,37 In addition, we continue to struggle to deliver timely, coordinated, and consistent care due to a multitude of factors, including insurance coverage policies, patient participation and acceptance, availability of needed care, and cost. It is also increasingly apparent that pain can be seen as a barometer of population health and that addressing pain will not be successful in the absence of addressing larger public health issues. The opioid epidemic has catalyzed collaboration between ASA and other professional societies and health care organizations to address many pain issues.13,38,39 ASA is also a member organization of the National Academy of Medicine Action Collaborative on Countering the U.S. Opioid Epidemic, which is entering its third year and represents a unique public-private partnership addressing pain management guidelines, education for the health professions, and prevention, treatment, and recovery services. These relationships represent natural routes for the dissemination of best practices in evidence-based pain management. Widespread adoption of video telehealth technology during the pandemic40 is increasing patient access to pain medicine experts and other critical health care professionals and has the potential to decrease existing disparities in pain care and improve outcomes on a much broader basis.
The future of pain medicine, in our opinion, will bring advances in personalization, coordination, and implementation that will incorporate genetic testing, AI, and innovative models of care.
However, improved patient access to high-quality pain management will require a coordinated effort by clinicians, scientists, patients and caregivers, organizations and advocacy groups, regulatory bodies, and lawmakers.