Elsevier

The Lancet

Volume 377, Issue 9784, 25 June–1 July 2011, Pages 2226-2235
The Lancet

Series
Treatment of chronic non-cancer pain

https://doi.org/10.1016/S0140-6736(11)60402-9Get rights and content

Summary

Chronic pain is a pervasive problem that affects the patient, their significant others, and society in many ways. The past decade has seen advances in our understanding of the mechanisms underlying pain and in the availability of technically advanced diagnostic procedures; however, the most notable therapeutic changes have not been the development of novel evidenced-based methods, but rather changing trends in applications and practices within the available clinical armamentarium. We provide a general overview of empirical evidence for the most commonly used interventions in the management of chronic non-cancer pain, including pharmacological, interventional, physical, psychological, rehabilitative, and alternative modalities. Overall, currently available treatments provide modest improvements in pain and minimum improvements in physical and emotional functioning. The quality of evidence is mediocre and has not improved substantially during the past decade. There is a crucial need for assessment of combination treatments, identification of indicators of treatment response, and assessment of the benefit of matching of treatments to patient characteristics.

Introduction

WHO estimates that 20% of individuals worldwide have some degree of chronic pain.1 The presence of chronic pain has both direct health-care and associated indirect (eg, disability payments, lost productivity) costs. For example, estimates for the total cost of chronic pain exceed US$210 billion annually in the USA.2 These large amounts are not unique to the USA. In the UK, back pain alone is estimated to cost society $26–49 billion each year.3 For most of those affected, the presence of chronic pain compromises all aspects of their lives and the lives of their significant others (figure 1). Despite important advances in understanding of the neurophysiology of pain, the increasing availability of advanced diagnostic procedures, and the application of sophisticated therapeutic modalities and approaches, currently available treatments for chronic pain rarely result in complete resolution of symptoms. Thus, people with chronic pain will continue to live with some level of pain irrespective of the treatment or treatments they receive for the foreseeable future.

Chronic non-cancer pain is typically defined as pain lasting longer than 3 months or beyond the expected period of healing of tissue pathology.4 Pain severity, however, is not correlated with the amount of damage and symptoms can persist long after tissue damage from an antecedent injury resolves.4 Research suggests that chronic non-cancer pain can develop as a result of persistent stimulation of or changes to nociceptors due to localised tissue damage from an acute injury or disease (eg, osteoarthritis), or damage to the peripheral or central nervous system, or both (eg, painful diabetic neuropathy, poststroke pain, spinal cord injury), which might not be readily detectable with currently available diagnostic technologies.5

Key messages

  • Chronic pain is a pervasive health issue that exerts a substantial social and economic burden on both the affected individual and society

  • Mechanisms underlying chronic pain include a complex interaction of physiological, emotional, cognitive, social, and environmental factors

  • Treatment options include pharmacological approaches; interventional techniques including nerve blocks, surgery, implantable drug-delivery systems, and spinal-cord stimulators; exercise and physical rehabilitation; psychological treatments; interdisciplinary treatment; and complementary and alternative treatments

  • In view of the complex nature of chronic pain, treatment often necessitates use of a blend of different approaches

  • Overall, present treatment options result in modest improvements at best, and part of chronic pain management should include dialogue with the patient about realistic expectations of pain relief, and bring focus to improvement of function

Pain does not occur in a vacuum. Individuals' unique genotypes, previous learning histories, environmental and socioeconomic resources, cognitive, emotional, and behavioural factors, and physical pathology interact to mediate and moderate the experience of pain (figure 2).6 Thus, to understand and treat patients with pain requires that consideration be given to all contributing facets. This complexity has bedevilled health-care providers, people experiencing pain, their significant others, and society since earliest recorded history. We provide a brief overview of, and evidence for the effectiveness of, the most commonly prescribed treatments for chronic non-cancer pain.

Section snippets

Treatment overview

A growing array of pharmaceutical, surgical, neuroaugmentative, somatic, behavioural, rehabilitative, and complementary and alternative treatment options are available for the management of patients with chronic pain. However, overall treatment effectiveness remains inconsistent and fairly poor. Moreover, even when treatments effectively reduce pain, they often do not produce concomitant improvements in physical and emotional functioning and overall health-related quality of life.7

The focus of

Background

Oral drugs have been the mainstay of treatment for pain during past centuries, and the use of drugs to treat pain has expanded exponentially in recent years, with increases in expenditures of 188% between 1996 and 2005.7 We review evidence for classes of drugs most commonly used for treatment of chronic non-cancer pain.

Opioids

Retail sales for opioids, the most common class of drug prescribed in the USA, increased by 176% from 1997 to 2006.8 Despite this striking escalation, their use remains

Background

Interventional pain medicine involves application of various techniques that can be used to diagnose or locate an individual's source of pain or provide therapeutic pain relief. Interventional medicine is most frequently used when a specific area of the spine is thought to be contributing to an individual's pain (ie, discogenic or sacroiliac joint pain) and there is no consensus with respect to optimum diagnostic criteria. The focus of our review is therapeutic intervention, so we will not

Physical, rehabilitation, and psychological approaches

Although evidence suggests that exercise can effectively decrease pain and improve function, improvements are small (<30% reduction in pain and <20% improvement in function).74 Systematic reviews also suggest that exercise intervention affects work disability status;75, 76 however, no conclusions could be made about exercise type. Moreover, patient adherence can be an impediment. Exercise treatments vary widely and are often incorporated as part of multimodal and rehabilitative treatment

Complementary and alternative medicine and other non-pharmacological approaches

Complementary and alternative medicine (CAM) includes a wide array of treatments that are not regarded as part of conventional medicine. A comprehensive review of all modalities is beyond the scope of this paper, but we address three of the most common modalities used, as well as those with the best evidence for treatment of chronic non-cancer pain. The evidence that we review is largely based on a recent systematic review89 of CAM effectiveness for chronic non-cancer pain. We refer interested

Conclusions

Ideally, we would include a table summarising the conclusions about treatments for chronic non-cancer pain covering all of modalities described. However, this approach is inappropriate because drawing of conclusions between the therapeutic approaches is impossible, since the meta-analyses and systematic reviews that we used vary widely in terms of diagnostic criteria used for the different conditions, outcome measures studied, criteria used to select studies for inclusion, inconsistency in some

Search strategy and selection criteria

We searched Medline (between 2000, and July, 2010), Embase (2000–10), and Cochrane (2005–10) using the search terms “chronic pain” or “chronic non-cancer pain”, and limited the field to “title/abstract”. We focused mainly on meta-analyses, systematic reviews, and guidelines published within the past 5 years; however, we also made use of the reference lists of articles identified by this search strategy, highly regarded older publications, and the authors' personal reference lists. From this

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