- Email: [email protected]
Chronic Pain
Chronic Pain
Preface Chronic Pain
James P. Robinson, MD, PhD Editors
Virtaj Singh, MD
This issue of the Physical Medicine and Rehabilitation Clinics of North America deals with strategies for evaluating and treating chronic pain. Physiatrists need skill in managing chronic pain because they encounter it frequently. Some physiatrists focus their clinical practices on patients who have pain as their major reason for seeking health care. These include physiatrists who work at pain centers, and ones who focus on the management of spinal disorders. Other physiatrists treat patients who are disabled by conditions that are not necessarily painful, such as spinal cord injury and stroke. For these physicians, pain might be construed as a secondary problem that complicates their attempts to rehabilitate patients. Unfortunately, it is a secondary problem that they are likely to encounter routinely, since epidemiologic research demonstrates a high prevalence of chronic pain in most of the patient populations that physiatrists treat.
APPROACHES TO PAIN
Physicians usually provide an eclectic mixture of therapies when they treat patients with chronic pain. Some of the therapies defy any simple classification scheme. For purposes of exposition, though, it is possible to classify most of them into 3 broad groups: curative/disease modifying, rehabilitative, and palliative. The curative approach is the simplest to understand and the preferred one when it is applicable. From this perspective, pain is a symptom that, in combination with other symptoms and signs, helps the physician identify a pathophysiologic process that becomes the target of treatment. In an ideal situation, once the underlying biological disturbance has been identified and reversed, the patient’s symptoms resolve without any additional treatments. Common examples of pain treatment based on the curative perspective include internal fixation and casting for a patient who presents with a painful wrist fracture, appendectomy for a patient who presents with right lower quadrant pain secondary to appendicitis, and angioplasty for a patient who presents with chest pain secondary to cardiac ischemia. Phys Med Rehabil Clin N Am 26 (2015) xiii–xvii http://dx.doi.org/10.1016/j.pmr.2015.01.006 1047-9651/15/$ – see front matter Ó 2015 Published by Elsevier Inc.
pmr.theclinics.com
xiv
Preface
Unfortunately, attempts to relieve pain by curing an “upstream” pathophysiologic process sometimes fail. The reasons for such failure are multiple. An obvious one is that physicians sometimes have difficulty identifying the offending pathophysiologic process. This situation frequently occurs when physicians attempt to help patients with chronic pain, perhaps because the underlying problem in these patients is often an alteration in the manner in which their nervous systems encode and process sensory information, rather than ongoing nociception from tissue injury. A rehabilitative model to pain management is most appropriate when 2 conditions apply: the curative model is not appropriate, and a major goal of the pain management program is to improve a patient’s ability to function. Most of the articles in this issue of the Physical Medicine and Rehabilitation Clinics of North America incorporate a rehabilitative model. In a general way, pain rehabilitation is similar to rehabilitation of any medical condition—its goal is to optimize functioning through a combination of physical conditioning, skills training, education, and mobilization of patients’ psychological resources. Many of the patients treated by physiatrists undergo rehabilitative treatment for disorders (eg, spinal cord injury) that may be associated with pain, but invariably involve numerous functional deficits unrelated to pain. For these patients, pain rehabilitation becomes a component of the overall rehabilitation program. Thus, for example, a paraplegic who reports shoulder pain as he transfers or uses his wheelchair might experience pain resolution as a result of conditioning to improve his upper body strength and training to improve his transfer techniques. In other settings, pain is the focus of rehabilitative treatment. The best example of this is multidisciplinary pain rehabilitation. Although rehabilitative therapies influence pain indirectly by addressing secondary effects of the pain (eg, deconditioning) and improving patients’ coping skills, palliative therapies focus directly on the pain experience itself. For example, opiates can blunt the experience of pain, without requiring patients to do the kind of work that is demanded by rehabilitative therapies. In practical situations, physicians typically manage chronic pain by some combination of rehabilitative and palliative strategies. For example, they will frequently prescribe medications to ease the pain experiences of patients, and at the same time, refer the patients to physical therapy in order to improve their functional capabilities. PREVIEW
The present issue of the Physical Medicine and Rehabilitaion Clinics of North America starts with an article on altered nervous system functioning in chronic pain. Most pain specialists believe that such altered functioning plays a key role in many chronic pain conditions and, to a large extent, explains why these conditions are difficult to treat. However, unless physicians have reliable methods to determine whether the altered functioning is occurring in individual patients, the hypothesis that chronic pain is often governed by altered nervous system functioning (rather than ongoing nociception from damaged tissues) is tenuous. The authors of this article have done extensive research on methods to assess altered nervous system functioning among pain patients and summarize their findings in the article. The article by Seroussi addresses the crucial practical issue of assessment of chronic pain. Early on in medical school, students are taught the importance of taking a thorough history and conducting a comprehensive physical examination. This indepth assessment is of particular importance when treating patients with chronic pain. Although physiatrists are typically well trained in the performance of thorough
Preface
neuromuscular examinations, accurate assessment in patients with chronic pain also requires the ability to identify comorbid factors, such as depression, deconditioning, disability, substance abuse, and so forth. This article discusses how to perform a thorough biopsychosocial assessment in the setting of chronic pain. Broadly speaking, nine articles address treatment options for patients with chronic pain and various issues that physicians should consider when developing treatment plans. More specifically, 2 articles address pharmacologic management of chronic pain. The article by Ballantyne is devoted entirely to a discussion of opioid therapy. This subject is crucial in large part because of the enormous changes that have occurred over the past 20 years in our understanding of the pros and cons of such therapy. The article by Tauben discusses a wide range of pharmacologic agents other than opioids that can be prescribed for patients with various chronic pain problems. These agents include acetaminophen, nonsteroidal anti-inflammatory medications, steroids, antidepressants, anticonvulsants, benzodiazepines, and less widely used agents (eg, ketamine). The article by Singh describes injection therapies that can be used in the treatment of chronic pain. It is important to note that some injections may be of limited utility by the time pain becomes chronic. However, there is sometimes a limited role for injections to help clarify potential sources of pain (“pain generators”) and facilitate participation in a more active rehabilitation program. There is extant literature (including prior issues of the Physical Medicine and Rehabilitation Clinics of North America) that addresses the use of epidural steroid injections and facet injections for the treatment of spinal pain, both axial and radicular. As such, these topics will not be covered in this article. Instead, less well-covered topics are the focus, including trigger point injections, prolotherapy and other regenerative injections, and botulinum toxin injections. The article by Kroll discusses exercise therapy for chronic pain. The material in this article is particularly important for 2 reasons. First, exercise is the most direct form of rehabilitative treatment—it directly addresses and attempts to reverse functional limitations that patients have because of their pain. Second, physiatrists have more expertise in exercise therapy than physicians with other kinds of training. As a result, they are in an optimal position to supervise exercise programs. Many patients with chronic pain have coexisting emotional dysfunction. Physiatrists who treat these patients need to have a high index of suspicion for the emotional problems that are likely to plague their patients, and they need to understand the perspectives and treatment approaches of the psychiatrists and clinical psychologists who are often called on to intervene. The article by Howe and colleagues addresses psychiatric and psychological problems that are commonly seen in patients with chronic pain. It is written from the perspectives of psychiatrists (Howe and Sullivan) and a psychologist (Robinson). Two articles address issues that are crucially important in the management of chronic pain, but are often not emphasized in traditional medical training. In particular, sleep, the focus of the article by Fine, has emerged as an area that demands attention. The reason for this is that patients with chronic pain often find themselves in a vicious circle. Their pain and accompanying emotional distress make it difficult to sleep, and their inadequate sleep leaves them exhausted and less ready to cope with pain. Tick’s article addresses the role of nutrition in chronic pain and outlines several practical strategies that physicians can follow to assess and remediate nutritional deficiencies in their patients with chronic pain. The article by Simpson addresses another arena that typically receives little attention in traditional medical training—complementary and alternative therapies (CAM).
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Preface
As Simpson makes clear, a high proportion of patients with chronic pain avails themselves of CAM therapies, and evidence for the effectiveness of many CAM therapies is as good as evidence for allopathic therapies. Brief descriptions are included of the rationales for several common CAM therapies and of the evidence supporting their effectiveness. The article by Malladi addresses multidisciplinary pain rehabilitation. There are at least 2 reasons physiatrists should be familiar with this approach to chronic pain. One reason is that multidisciplinary treatment of some kind is recommended by virtually every expert panel that provides guidelines for treating various chronic pain problems. A major reason for this is that chronic pain has multifactorial roots. It is typical for patients to suffer from deconditioning, emotional dysfunction, sleep deprivation, various nutritional deficiencies, and work disability. It is virtually impossible for a single physician to address all these domains during office visits with a patient. Second, the structure and organization of multidisciplinary pain rehabilitation programs are similar in many ways to the rehabilitation programs used for common rehabilitation problems such as stroke or spinal cord injury. In fact, the architect of the original multidisciplinary pain rehabilitation program, which was started at the University of Washington (UW) in the late 1960s, was a psychologist in the Department of Rehabilitation Medicine at UW. The articles by Seroussi and colleagues and Murinova and Krashin describe how concepts developed in the earlier articles of the issue can be applied to 2 populations of patients with chronic pain: those with whiplash injuries, and those with chronic headaches. These 2 chronic pain populations frequently present in a physiatric practice. Finally, the article by Robinson and Glass addresses the management of pain in patients with workers’ compensation claims. The discussion emphasizes the fact that a physician who treats pain in an injured worker must do much more than provide effective medical care for the patient. In particular, such a physician must be prepared to interact with several different interested parties and to address complex issues regarding the patient’s disability. A FINAL WORD
Many physicians find chronic pain difficult and emotionally challenging to treat. Their reticence reflects 3 basic facts about chronic pain. First, pain is a personal experience that cannot be fully confirmed by a physician or any other third party. Thus, a treating physician will frequently experience uncertainty about how to interpret a patient’s pain complaints. This ambiguity becomes especially challenging if the patient demands high doses of opiates to control pain or reports a degree of incapacitation that appears to be excessive relative to the severity of the medical condition. Second, chronic pain reflects the combined influence of a wide range of biological, psychological, and social factors. Thus, a physician who tries to understand the factors underlying a patient’s pain complaints must have expertise in areas other than just the pathophysiology of injuries and diseases. Third, many of the commonly used treatments for chronic pain have not been validated in well-designed studies, and the treatments that have been validated generally demonstrate only modestly beneficial effects. As a result, a physician who treats chronic pain usually cannot practice evidence-based medicine and must be prepared to encounter frequent failures. The articles in this issue of the Physical Medicine and Rehabilitation Clinics of North America do not eliminate the above challenges. In particular, since the various therapeutic approaches described in the issue have essentially never been subjected to
Preface
head-to-head comparisons, the material in this issue does not provide anything like a simple algorithm to follow when treating pain patients. But we do believe that the articles will provide physiatrists with an appreciation of the complexities of chronic pain and also with a set of practical strategies that they can use when they agree to manage patients with chronic pain. ACKNOWLEDGMENTS
We would like to express our appreciation to the authors of this issue of the Physical Medicine and Rehabilitation Clinics of North America. They are all very busy clinicians and scholars. It is impressive that they were willing to take the time to write their articles. We believe that their cumulative efforts have resulted in an issue that provides both conceptual clarity and practical tools for physiatrists. James P. Robinson, MD, PhD Department of Rehabilitation Medicine University of Washington 4225 Roosevelt Way NE, 4th floor Seattle, WA 98105, USA Virtaj Singh, MD Department of Rehabilitation Medicine University of Washington Seattle Spine & Sports Medicine 3213 Eastlake Avenue E, Suite A Seattle, WA, 98102, USA E-mail addresses: [email protected] (J.P. Robinson) [email protected] (V. Singh)
xvii
Preface Chronic Pain
James P. Robinson, MD, PhD Editors
Virtaj Singh, MD
This issue of the Physical Medicine and Rehabilitation Clinics of North America deals with strategies for evaluating and treating chronic pain. Physiatrists need skill in managing chronic pain because they encounter it frequently. Some physiatrists focus their clinical practices on patients who have pain as their major reason for seeking health care. These include physiatrists who work at pain centers, and ones who focus on the management of spinal disorders. Other physiatrists treat patients who are disabled by conditions that are not necessarily painful, such as spinal cord injury and stroke. For these physicians, pain might be construed as a secondary problem that complicates their attempts to rehabilitate patients. Unfortunately, it is a secondary problem that they are likely to encounter routinely, since epidemiologic research demonstrates a high prevalence of chronic pain in most of the patient populations that physiatrists treat.
APPROACHES TO PAIN
Physicians usually provide an eclectic mixture of therapies when they treat patients with chronic pain. Some of the therapies defy any simple classification scheme. For purposes of exposition, though, it is possible to classify most of them into 3 broad groups: curative/disease modifying, rehabilitative, and palliative. The curative approach is the simplest to understand and the preferred one when it is applicable. From this perspective, pain is a symptom that, in combination with other symptoms and signs, helps the physician identify a pathophysiologic process that becomes the target of treatment. In an ideal situation, once the underlying biological disturbance has been identified and reversed, the patient’s symptoms resolve without any additional treatments. Common examples of pain treatment based on the curative perspective include internal fixation and casting for a patient who presents with a painful wrist fracture, appendectomy for a patient who presents with right lower quadrant pain secondary to appendicitis, and angioplasty for a patient who presents with chest pain secondary to cardiac ischemia. Phys Med Rehabil Clin N Am 26 (2015) xiii–xvii http://dx.doi.org/10.1016/j.pmr.2015.01.006 1047-9651/15/$ – see front matter Ó 2015 Published by Elsevier Inc.
pmr.theclinics.com
xiv
Preface
Unfortunately, attempts to relieve pain by curing an “upstream” pathophysiologic process sometimes fail. The reasons for such failure are multiple. An obvious one is that physicians sometimes have difficulty identifying the offending pathophysiologic process. This situation frequently occurs when physicians attempt to help patients with chronic pain, perhaps because the underlying problem in these patients is often an alteration in the manner in which their nervous systems encode and process sensory information, rather than ongoing nociception from tissue injury. A rehabilitative model to pain management is most appropriate when 2 conditions apply: the curative model is not appropriate, and a major goal of the pain management program is to improve a patient’s ability to function. Most of the articles in this issue of the Physical Medicine and Rehabilitation Clinics of North America incorporate a rehabilitative model. In a general way, pain rehabilitation is similar to rehabilitation of any medical condition—its goal is to optimize functioning through a combination of physical conditioning, skills training, education, and mobilization of patients’ psychological resources. Many of the patients treated by physiatrists undergo rehabilitative treatment for disorders (eg, spinal cord injury) that may be associated with pain, but invariably involve numerous functional deficits unrelated to pain. For these patients, pain rehabilitation becomes a component of the overall rehabilitation program. Thus, for example, a paraplegic who reports shoulder pain as he transfers or uses his wheelchair might experience pain resolution as a result of conditioning to improve his upper body strength and training to improve his transfer techniques. In other settings, pain is the focus of rehabilitative treatment. The best example of this is multidisciplinary pain rehabilitation. Although rehabilitative therapies influence pain indirectly by addressing secondary effects of the pain (eg, deconditioning) and improving patients’ coping skills, palliative therapies focus directly on the pain experience itself. For example, opiates can blunt the experience of pain, without requiring patients to do the kind of work that is demanded by rehabilitative therapies. In practical situations, physicians typically manage chronic pain by some combination of rehabilitative and palliative strategies. For example, they will frequently prescribe medications to ease the pain experiences of patients, and at the same time, refer the patients to physical therapy in order to improve their functional capabilities. PREVIEW
The present issue of the Physical Medicine and Rehabilitaion Clinics of North America starts with an article on altered nervous system functioning in chronic pain. Most pain specialists believe that such altered functioning plays a key role in many chronic pain conditions and, to a large extent, explains why these conditions are difficult to treat. However, unless physicians have reliable methods to determine whether the altered functioning is occurring in individual patients, the hypothesis that chronic pain is often governed by altered nervous system functioning (rather than ongoing nociception from damaged tissues) is tenuous. The authors of this article have done extensive research on methods to assess altered nervous system functioning among pain patients and summarize their findings in the article. The article by Seroussi addresses the crucial practical issue of assessment of chronic pain. Early on in medical school, students are taught the importance of taking a thorough history and conducting a comprehensive physical examination. This indepth assessment is of particular importance when treating patients with chronic pain. Although physiatrists are typically well trained in the performance of thorough
Preface
neuromuscular examinations, accurate assessment in patients with chronic pain also requires the ability to identify comorbid factors, such as depression, deconditioning, disability, substance abuse, and so forth. This article discusses how to perform a thorough biopsychosocial assessment in the setting of chronic pain. Broadly speaking, nine articles address treatment options for patients with chronic pain and various issues that physicians should consider when developing treatment plans. More specifically, 2 articles address pharmacologic management of chronic pain. The article by Ballantyne is devoted entirely to a discussion of opioid therapy. This subject is crucial in large part because of the enormous changes that have occurred over the past 20 years in our understanding of the pros and cons of such therapy. The article by Tauben discusses a wide range of pharmacologic agents other than opioids that can be prescribed for patients with various chronic pain problems. These agents include acetaminophen, nonsteroidal anti-inflammatory medications, steroids, antidepressants, anticonvulsants, benzodiazepines, and less widely used agents (eg, ketamine). The article by Singh describes injection therapies that can be used in the treatment of chronic pain. It is important to note that some injections may be of limited utility by the time pain becomes chronic. However, there is sometimes a limited role for injections to help clarify potential sources of pain (“pain generators”) and facilitate participation in a more active rehabilitation program. There is extant literature (including prior issues of the Physical Medicine and Rehabilitation Clinics of North America) that addresses the use of epidural steroid injections and facet injections for the treatment of spinal pain, both axial and radicular. As such, these topics will not be covered in this article. Instead, less well-covered topics are the focus, including trigger point injections, prolotherapy and other regenerative injections, and botulinum toxin injections. The article by Kroll discusses exercise therapy for chronic pain. The material in this article is particularly important for 2 reasons. First, exercise is the most direct form of rehabilitative treatment—it directly addresses and attempts to reverse functional limitations that patients have because of their pain. Second, physiatrists have more expertise in exercise therapy than physicians with other kinds of training. As a result, they are in an optimal position to supervise exercise programs. Many patients with chronic pain have coexisting emotional dysfunction. Physiatrists who treat these patients need to have a high index of suspicion for the emotional problems that are likely to plague their patients, and they need to understand the perspectives and treatment approaches of the psychiatrists and clinical psychologists who are often called on to intervene. The article by Howe and colleagues addresses psychiatric and psychological problems that are commonly seen in patients with chronic pain. It is written from the perspectives of psychiatrists (Howe and Sullivan) and a psychologist (Robinson). Two articles address issues that are crucially important in the management of chronic pain, but are often not emphasized in traditional medical training. In particular, sleep, the focus of the article by Fine, has emerged as an area that demands attention. The reason for this is that patients with chronic pain often find themselves in a vicious circle. Their pain and accompanying emotional distress make it difficult to sleep, and their inadequate sleep leaves them exhausted and less ready to cope with pain. Tick’s article addresses the role of nutrition in chronic pain and outlines several practical strategies that physicians can follow to assess and remediate nutritional deficiencies in their patients with chronic pain. The article by Simpson addresses another arena that typically receives little attention in traditional medical training—complementary and alternative therapies (CAM).
xv
xvi
Preface
As Simpson makes clear, a high proportion of patients with chronic pain avails themselves of CAM therapies, and evidence for the effectiveness of many CAM therapies is as good as evidence for allopathic therapies. Brief descriptions are included of the rationales for several common CAM therapies and of the evidence supporting their effectiveness. The article by Malladi addresses multidisciplinary pain rehabilitation. There are at least 2 reasons physiatrists should be familiar with this approach to chronic pain. One reason is that multidisciplinary treatment of some kind is recommended by virtually every expert panel that provides guidelines for treating various chronic pain problems. A major reason for this is that chronic pain has multifactorial roots. It is typical for patients to suffer from deconditioning, emotional dysfunction, sleep deprivation, various nutritional deficiencies, and work disability. It is virtually impossible for a single physician to address all these domains during office visits with a patient. Second, the structure and organization of multidisciplinary pain rehabilitation programs are similar in many ways to the rehabilitation programs used for common rehabilitation problems such as stroke or spinal cord injury. In fact, the architect of the original multidisciplinary pain rehabilitation program, which was started at the University of Washington (UW) in the late 1960s, was a psychologist in the Department of Rehabilitation Medicine at UW. The articles by Seroussi and colleagues and Murinova and Krashin describe how concepts developed in the earlier articles of the issue can be applied to 2 populations of patients with chronic pain: those with whiplash injuries, and those with chronic headaches. These 2 chronic pain populations frequently present in a physiatric practice. Finally, the article by Robinson and Glass addresses the management of pain in patients with workers’ compensation claims. The discussion emphasizes the fact that a physician who treats pain in an injured worker must do much more than provide effective medical care for the patient. In particular, such a physician must be prepared to interact with several different interested parties and to address complex issues regarding the patient’s disability. A FINAL WORD
Many physicians find chronic pain difficult and emotionally challenging to treat. Their reticence reflects 3 basic facts about chronic pain. First, pain is a personal experience that cannot be fully confirmed by a physician or any other third party. Thus, a treating physician will frequently experience uncertainty about how to interpret a patient’s pain complaints. This ambiguity becomes especially challenging if the patient demands high doses of opiates to control pain or reports a degree of incapacitation that appears to be excessive relative to the severity of the medical condition. Second, chronic pain reflects the combined influence of a wide range of biological, psychological, and social factors. Thus, a physician who tries to understand the factors underlying a patient’s pain complaints must have expertise in areas other than just the pathophysiology of injuries and diseases. Third, many of the commonly used treatments for chronic pain have not been validated in well-designed studies, and the treatments that have been validated generally demonstrate only modestly beneficial effects. As a result, a physician who treats chronic pain usually cannot practice evidence-based medicine and must be prepared to encounter frequent failures. The articles in this issue of the Physical Medicine and Rehabilitation Clinics of North America do not eliminate the above challenges. In particular, since the various therapeutic approaches described in the issue have essentially never been subjected to
Preface
head-to-head comparisons, the material in this issue does not provide anything like a simple algorithm to follow when treating pain patients. But we do believe that the articles will provide physiatrists with an appreciation of the complexities of chronic pain and also with a set of practical strategies that they can use when they agree to manage patients with chronic pain. ACKNOWLEDGMENTS
We would like to express our appreciation to the authors of this issue of the Physical Medicine and Rehabilitation Clinics of North America. They are all very busy clinicians and scholars. It is impressive that they were willing to take the time to write their articles. We believe that their cumulative efforts have resulted in an issue that provides both conceptual clarity and practical tools for physiatrists. James P. Robinson, MD, PhD Department of Rehabilitation Medicine University of Washington 4225 Roosevelt Way NE, 4th floor Seattle, WA 98105, USA Virtaj Singh, MD Department of Rehabilitation Medicine University of Washington Seattle Spine & Sports Medicine 3213 Eastlake Avenue E, Suite A Seattle, WA, 98102, USA E-mail addresses: [email protected] (J.P. Robinson) [email protected] (V. Singh)
xvii