Learning Objectives/Outcomes: After participating in this continuing professional development activity, the provider should be better able to:
1. Describe the risks of pain assessment strategies that emphasize severity.
2. Identify screening tools for patients at high risk of postsurgical pain.
3. Recommend appropriate preoperative nonpharmacologic pain management.
The first of this 2-part series provides an overview of chronic postsurgical pain (CPSP), with historical context, including the opioid crisis in the United States and other countries.
In the second part, to appear in the February 2021 issue of Topics in Pain Management (vol. 36, no. 7), there will be a deeper focus on CPSP, with an understanding that pain should not be considered as the fifth vital sign. Part 2 also will delineate risk factors for the development of chronic pain and explore diverse means to assess and mitigate the development of chronic pain.
Overview
The global opioid crisis and the widespread acknowledgment of the great difficulty in managing patients with chronic pain have created recognition for the importance of mitigating the risk of developing CPSP, pharmaceutical opioid use disorder (OUD), and sequelae of those disorders. These factors, along with many others, prompted the International Association for the Study of Pain (IASP) to recognize 2017 as the IASP Global Year Against Pain After Surgery and, now, 2020 as the IASP Global Year for the Prevention of Pain.
CPSP has become a health priority that is included in the International Classification of Diseases, Eleventh Revision (ICD-11).1 It was officially endorsed by all members of the World Health Organization in Geneva, Switzerland, during the 72nd World Health Assembly in 2019.
Patients sometimes spiral into CPSP despite our best efforts at management. The majority of patients who ultimately develop CPSP start with an episode of severe acute pain and pass through multiple levels of the health care system, often being managed by several health professionals, whether sequentially or concurrently, during the course of care. Although estimates from epidemiological studies vary, there are now a great deal of data showing that CPSP occurs in 10% to 30% of all surgical patients (reporting pain persisting 1 year after surgery) and that 5% of all surgical patients report their CPSP is severe enough that it is disabling.2-4
In essence, chronic pain conditions tend to start as acute pain.5 CPSP usually begins as pain in the acute postoperative phase that responds poorly to analgesia. Shortly afterward, it transitions into a neuropathic pain condition that responds poorly to opioids.6 By this time, patients have often been inadvertently conditioned by a lengthy stepwise approach to passive pain management. This approach shifts the patient's locus of control externally and decreases the sense of self-efficacy, while increasing the patient's expectation that another passive intervention, such as interventional pain management or another surgical procedure, will cure the pain.
CPSP was only initially identified in the literature in 1998,7 but has since become such a significant issue that many national guidelines have been published worldwide regarding best practices for the management of patients with musculoskeletal pain to effectively mitigate the risk of CPSP. These all prioritize reasonable attempts at keeping patients opioid-naive.
Historical Context
Opioids have been used in the United States to treat pain before, during, and after surgery since the early 1860s during the US Civil War. However, published research studies did not implicate surgery as a major risk factor for chronic pain until after the beginning of the current opioid crisis in this country just over 20 years ago.7 The widespread and protracted use of opioids for pain management today remains profoundly enmeshed with CPSP.
Medical providers may often feel they have a limited number of effective alternatives for pain management and resort to opioid analgesia, as it has good efficacy in the immediate-term and is generally considered safe to prescribe. Although opioids may outperform many nonpharmacologic pain management approaches when used for short periods, many well-designed studies have shown that pharmaceutical-grade opioids carry significant risks of addiction and overdose with long-term use for some patients, even when used as directed by a physician. Studies using large-scale patient surveys have recognized that the large majority of the victims of this opioid crisis have started on the path to opioid overdose by taking opioid pain medication prescribed by their physician.
Since the beginning of the current opioid crisis, close to 500,000 Americans have died from opioid overdose. Today, 2.3 million Americans have an OUD, and 74% of them initially had a narcotic prescription.8 Once patients develop an obvious pattern of problematic opioid use and possible drug-seeking behavior, medical providers decline to continue prescribing opioids for pain management in hopes of protecting them from iatrogenic downward spiral. By this time, it may already be too late for some of these patients, as they turn to the misuse of alcohol, illicit opioids, or diverted prescription opioids in attempts to self-medicate. Indeed, recently published data show that physician-prescribed narcotics are the gateway drugs that lead to illicit narcotics for 80% of all Americans who die from opioid overdose each year.9
Offering hope, the US Centers for Disease Control and Prevention 2016 Guideline for Prescribing Opioids for Chronic Pain10 led to a 2% decrease in opioid overdose deaths in 2018.11 But total opioid deaths began rising again in 2019, surpassing 50,000 deaths for the first time in US history that year.12 Epidemiologists and public health experts have announced the emergence of a global syndemic created by the conjunction of the opioid and coronavirus disease-2019 (COVID-19) pandemics.13 This comes with the recognition of the increased risk of using narcotics, whether illicit or prescribed, while living in relative social isolation for a protracted period. Early data from the beginning of the COVID-19 pandemic suggest the opioid death rate is continuing to rise in the United States (Figure 1).
Although the opioid crisis is classified as a global pandemic, it certainly is more severe in the United States than in any other country worldwide, whether measured by prevalence, total deaths, deaths per capita, disability-adjusted life years, or economic burden.
Epidemiologists and public health experts have announced the emergence of a global syndemic created by the conjunction of the opioid and COVID-19 pandemics.
The reasons for why the United States has a more severe opioid crisis than other countries are multifactorial, but there are clear cultural issues involved. The expectation of on-demand, physician-provided pain relief has resulted in a health care system in which 38% of American adults report using prescription opioids within the past year.15 By comparison, several European nations reserve the practice of opioid-prescribing for specialists, which may explain the much lower prevalence of OUDs in Europe than in the United States, where half of all opioid prescriptions are written by general practitioners. Japan also reports far lower rates of opioid-prescribing than the United States, likely a byproduct of its national health system reserving oxycodone for advanced cancer pain and establishing associations with end-of-life care that cultivates much stronger antiopioid attitudes than those seen in the United States.
Chronic Postsurgical Pain
The definition of CPSP included in the ICD-11 is pain that persists for a minimum of 3 months after an acute postoperative episode of pain and that:
* Is localized to the surgical site or a referred area;
* Develops or increases in intensity after a surgery;
* Causes a significant negative impact on quality of life;
* May develop after an asymptomatic period; and
* Is not better explained by another cause (eg, infection, malignancy, or a preexisting pain condition).16,17
Among patients receiving prescription opioids, prescribing began after surgery for 27% of them.18 Approximately 6% of postoperative patients develop an OUD whether surgery was major or minor.19 This is more closely associated with behavioral and pain disorders than the complexity of the procedure itself. This further suggests that surgical factors are less strongly correlated to opioid misuse than are patient-level predictors that can be identified during screening. This is well-aligned with the position of the IASP as reflected in their published notes related to their revised 2020 definition of pain20 that recognizes pain as always being a personal experience that is learned through the patient's life experiences and that is influenced to varying degrees by biological, psychological, and social factors.
CPSP is known to correlate with poorer surgical outcomes, poorer rehabilitation outcomes, decreased functional ability, increased psychological trauma, increased health care costs, and decreased quality of life.6,21-26 Acute and chronic pain after surgery both have adverse effects on patient outcomes and warrant clinical management, but postsurgical pain management has historically been dominated by opioids and other pharmaceutical products, in addition to interventional pain management procedures that are often ineffective.
Iatrogenicity and Chronic Pain
Over time, pharmaceutical opioids are known to progressively cause hyperalgesia, increasing the likelihood of dependence.27 Subsequently, some patients begin misusing opioids within the first week of use, and this becomes more likely with both increased dose and increased duration of use.28 In the United States, prescribing of opioids for chronic pain patients is associated with misuse in 1 in 4, heroin use in 1 in 20, and a high rate of polysubstance use,29 all of which increase the risk of opioid overdose death. After many decades of uninterrupted increases, US life expectancy decreased from 2014 to 2018, largely driven by opioid overdose deaths.15
To mitigate the risk of developing OUD, prescribing opioids requires consideration of the patient's entire history. Routine information such as pain intensity, age, previous injury, surgical history, physical health, and mental health is important to collect. Medical and physiological concerns that can alter the pharmacokinetics and pharmacodynamics of prescription medications are imperative to discern because they may potentially undermine the clinical effectiveness of opioids while increasing their risk profile. A description of the patient's pain that includes intensity as merely one of many aspects can provide insight into the patient's pain experience while keeping in mind that psychosocial risk factors contribute to this picture in a substantial way.
Health professionals who treat someone in pain may understandably attempt to solve the patient's problem using available tools, even if these tools carry some degree of risk. Indeed, opioids do reliably offer some relief from the patient's symptoms. When a patient presents with persistent symptoms of pain after surgery, it is often the patient's expectation that opioids will continue to be prescribed postoperatively. Frustratingly, pharmaceutical interventions for pain have progressively limited short-term efficacy and poor long-term effectiveness. This carries a nonzero risk of harm, however, and it is not uncommon for patients to have developed a substance use disorder within the first week of opioid use.
Nine in 10 patients who present to an emergency department due to prescription opioid overdose are prescribed more opioids. Alarmingly, the vast majority of the time, these opioids are often represcribed by the same physician who prescribed them previously,30 suggesting this risk is usually difficult for prescribers to accurately estimate.
Pain Is No Longer the Fifth Vital Sign
Before 1995, opioid pain management was predominantly used for patients with pain related to major surgery, severe injury, or advanced cancer. As the central focus of the American Pain Society's Presidential Address in that year, attendees were rebuked for undertreating pain and exhorted to "consider pain the fifth vital sign."31 In addition to the existing clinical indications for opioid pain management at the time, then-President James N. Campbell, MD, implored the audience to additionally use opioid pain management for routine operations, recurrent back pain, "and myriad other diseases" and launched a formal campaign to change US pain management culture, targeting clinicians, health care companies, and policymakers.
Two of the notable achievements of this broad campaign to influence the American culture of pain management occurred 6 years later, the first being that The Joint Commission (TJC) issued revised standards in 2001 with examples strongly emphasizing quantitative pain measures to assess pain as a vital sign. This drove the other instrumental achievement of this campaign, being that the Centers for Medicare & Medicaid Services (CMS) added pain management questions to their Hospital Consumer Assessment of Healthcare Providers and Systems survey after discharge. Results of this survey can have an impact on hospital reimbursement rates. One of these new questions asked whether hospital staff had done "everything they could" to manage the patient's pain. This essentially had the effect of incentivizing hospitals to create policies that focused sharply on the effectiveness of treatments to reduce pain intensity. Within this 6-year span, hospitals adopted widespread use of the 11-point Numeric Rating Scale (NRS) across the United States and ushered in our current era of intensity-based pain assessment.
From 1997 to 2010, the percentage of patients with low back pain receiving prescription opioids increased from 15% to 45%.32 The increased use of opioids for postoperative pain management during this era has made minimal statistical improvement in pain severity. Meanwhile, after taking opioids for 1 month, patients show an increased sensitivity to pain with a 16% decrease in pain threshold and a 24% decrease in pain tolerance, on average.27 Due to this, efforts to reduce pain to 0 on the NRS is a primary driver of the opioid crisis, as these medications make people more susceptible to pain when taken for more than a few weeks.
Between 1995 and 2014, the rate of acute postoperative pain in the United States decreased by only 5 percentage points-from 80% to 75% of patients-whereas rates of no pain or mild pain changed by only 6 percentage points-increasing from 19% to 25%.33-36 This is striking, considering that these dates roughly frame the remarkable rise of the use of pharmaceutical opioids in the United States.
Intensity-based acute pain management policies have been shown to foster physical activity avoidance, expectations of rapid pain relief, and an external locus of control. Yielding to evidence of unintended harms, TJC removed these survey items. Revised TJC pain management standards, implemented in 2018, suggest that pain assessment should include a mechanism for identifying psychosocial risk factors for pain; involving patients in the development of their own treatment plan; creating realistic expectations and measurable goals; focusing reassessment on the impact of pain on physical function including monitoring opioid-prescribing patterns and, notably; promoting access to nonpharmacologic pain treatment.
Today, TJC neither incentivizes nor instructs hospitals to place an emphasis on pain as a vital sign. Despite the end of this campaign, problematic intensity-based pain assessment policies remain in place in hospitals around the United States, as there is no specific incentive for pain intensity to be removed as a focus of pain assessment.
Pain Assessment
Pain-specific patient-reported outcome measures (PROMs) are considered the gold standard of pain assessment. This is a broad category consisting of measures that investigate intensity (NRS, Visual Analog Scale, Faces), location (Ransford pain diagram), description (verbal descriptor scales), questionnaires, and pain diaries. However, many of these focus on their specific intended unidimensional aspect of a person's pain experience.
Growth in the awareness of the multidimensional nature of pain suggests that clinicians should use several PROMs to capture each dimension of a patient's pain experience; however, this can quickly become onerous on both the patient and the clinician. This has led to the creation, publication, and widespread validation of multidimensional PROMs, such as the Orebro Musculoskeletal Pain Questionnaire, that incorporate key items from earlier unidimensional PROMs and capture a far broader picture of the patient's pain experience than merely pain intensity.37
When reflecting upon pain assessment for patients with a primary symptom of pain, it may be useful to consider a fundamentally philosophical question: Who are the people who choose to become patients? Over 116 million US adults suffer from common chronic pain conditions,38 but most of these people do not seek medical care. What is it about a person's pain experience that leads them to seek guidance or solutions from a health professional?
Conclusion
Patients sometimes spiral into CPSP despite practitioners' best efforts at management. The majority of patients who ultimately develop CPSP start with an episode of severe acute pain and pass through multiple levels of the health care system, often being managed by several health professionals. Although estimates from epidemiological studies vary, there are now a great deal of data showing that CPSP occurs in 10% to 30% of all surgical patients and that 5% of all surgical patients report their CPSP is severe enough that it is disabling.
Opioid prescriptions began to rise in 1995 when a trend in medicine to recognize pain as the fifth vital sign by accrediting bodies such as TJC, federal regulators such as the CMS, and society leaders such as the American Pain Society began to change practice in hospitals and physician offices.
This increase in opioid prescriptions in many patients led to iatrogenic addiction, sometimes leading patients to drug-seeking behavior and even to street drugs such as heroin.
Meanwhile, social isolation that is a result of the COVID-19 pandemic has not helped.
Recently, published data show that physician-prescribed narcotics are the gateway drugs that lead to illicit narcotics for 80% of all Americans who die from opioid overdose each year.
In part 2 of this series, we will examine assessment and treatment of CPSP using nonopioid medications and interventions.
References