Chapter 84. Disability Assessment of Pain-Impaired Patients

Approximately one third of all Americans have a chronically painful condition; 50% to 60% of these individuals are partially or totally disabled. Cost estimates in the United States run as high as $79 billion a year in direct and indirect expenses, with 40 million physician visits annually due to chronically painful conditions.1 Much of these costs are related to the disability process including workers’ compensation, litigation, personal indemnity, lost productivity, and Social Security Administration (SSA) payments. There has been a 73% increase in workers’ compensation costs as a percentage of payroll in the period from 1980 to 1994, and in the same period, the medical costs in compensation cases rose 1.5 times faster than did general health care costs in the United States.2 Although from 1988 to 1996 the length of disability on workers’ compensation decreased by 60.9% and the average cost per claim decreased by 41.4%, this likely reflects state policy changes with more aggressive case management.3 Given that during this same period applications for SSI and SSDI rose by greater than 40% in 1992, one can assume that there may have been a shift from workers’ compensation to federal compensation. Interestingly, pain was a factor in 40% to 60% of these SSA claims.4 The reasons for this dramatic increase are multifactorial: increased social and vocational demands, and change in work ethics may have contributed. Health care professionals themselves may be a significant cause of this change. In one study, using the Health Care Providers’ Pain and Impairment Relationship Scale (HC-PAIRS), community health care providers had much lower expectations regarding the functional performance of patients with chronic low back pain than health care professionals who treated these patients with a functional restoration approach.5 Perhaps we demand too little from our chronic pain patients, therefore contributing to increased disability.

One question that is often raised is, what distinguishes those individuals with chronically painful conditions that are disabled from those that are not. Ideally, one would expect that there would be major differences in disease severity that could be assessed with the use of standard clinical methods. What is frustrating for many physicians dealing with the question of impairment and disability in chronic pain is that there are no generally accepted standards to assess these differences. The pain field lacks the tests and examination techniques that rise to the level of a gold standard to which all other clinical methods can be compared for validation. To illustrate the difficulty, it is all too common for a patient with severe congenital scoliosis who has undergone spinal fusion with instrumentation at multiple levels to have no pain and little in the way of functional limitations. Contrast this to another typical patient with a remote history of low back injury, minimal findings on examination and imaging studies, and yet, who has, by self-report, severe disabling pain. Many of the instruments used to predict outcome that utilize the self-report of the patient in various domains of pain, function, and psychological distress have to be used with caution in a disability assessment recognizing that “prediction of failure to return to work would be used as a predictor of certification of inability to work.”6

We begin by analyzing the current definitions of impairment and disability and point out where these definitions break down when it comes to occult conditions such as chronic pain. We then present the advances that have been made in this field over the last 10 years and propose a pragmatic, systematic approach to the functional evaluation of pain-impaired patients.

The terms impairment, disability, and handicap are commonly used in daily medical practice. Significant confusion, however, exists about the appropriate use of these terms. In addition to the well-known International Classification of Diseases (ICD), the World Health Organization (WHO) published the International Classification of Impairments, Disabilities, and Handicaps (ICIDH) in 1980.7 Because of dramatic demographic changes and technological advances, medical care in industrialized countries has had to address the increasing prevalence of chronic diseases and this has led to a change from a disease- to an illness-consequence focus. This shift required an internationally accepted, common language outside the traditional medical model to serve the needs of people with disabilities. It is no longer sufficient to record the occurrence of a disease and its consequences solely in terms of complete recovery or death.8 Many conditions, such as chronic pain, result in long-term, functional limitations that are nonfatal and which call for a different theoretical framework. Since its introduction, the ICIDH has been a widely accepted framework for understanding the consequences of a disease for a person at the structural, individual, and societal level (Fig. 84-1).

Impairment is defined as “any loss or abnormality of psychological, physiological or anatomical structure or function.” Examples of impairments are decreased range of motion or loss of strength. Disability that results from an impairment is “any restriction or lack of ability to perform an activity in the manner or within the range considered normal for a human being” and is represented by activity limitations such as difficulties with community ambulation, inability to perform activities of daily living (ADLs), or disturbances in appropriate social behaviors. A handicap is caused by an impairment or disability that “limits or prevents the fulfillment of a role that is normal (depending on age, sex, and social and cultural factors) for that individual.” For example, the inability to meet social obligations or fulfill occupational requirements may be a result of an impairment or disability.9

In summary, impairment is the result of an injury or disease at the level of the organ, that is, decreased range of motion or poor endurance. Disability describes the possible effects of an impairment at the level of the individual such as the inability to walk or lift. A handicap characterizes the consequences of impairment and disability at the level of the environment and society, that is, the work role.

Since the introduction of the ICIDH, the World Health Organization has worked on a revised version of the ICIDH, which is due to be released in the near future. It will put greater emphasis on presenting handicap as a description of the circumstances that people encounter due to the interaction between their impairment or disability and their physical and social environment. Disability will be defined as an activity limitation rather than inability and handicap as a participation restriction. One of the goals of the revised ICIDH is to provide a framework for functional diagnoses for persons with chronic limitations, similar to the medical diagnoses that comprise the ICD.8 This is a concept that may be particularly helpful in addressing the problems of chronic pain patients with occult impairments by focusing on the functional effects rather than the disease.

While the goal of the ICIDH is the maximization of societal participation and improvement in the quality of life of people with disabilities and changes in social practices at the international level, the American Medical Association (AMA) uses impairment evaluations as a medicolegal tool to guide physicians to assess, report on, and communicate information about the impairments of human organ systems.10 The purpose of the AMA evaluations is to estimate the severity of a person’s impairment, for example, to assist in the settlement of workers’ compensation cases, and therefore has entirely different implications than the ICIDH. Although the AMA definition of impairment closely parallels the WHO definition, one of the major criticisms of the AMA guidelines is that the rating of impairment is done in isolation without reference to the greater social context of potential disability and handicap. Physicians using the AMA guidelines determine impairment, but the matter of interest in medicolegal cases is disability or the patient’s work capacity. Although the AMA guidelines recognize that an impaired individual is not necessarily disabled (i.e., a surgeon who loses his leg is impaired but not disabled from performing his job as a surgeon if fitted with an appropriate prosthesis), the impairment rating system breaks down when there is a paucity of impairments with severe disability such as is often seen in chronic pain states.

The Social Security Administration (SSA) regulations define disability as an “inability to engage in any substantial gainful activity by reason of any medically determinable physical or mental impairment which can be expected to result in death or which has lasted or can be expected to last for a continuous period of not less than 12 months.11 For the purposes of SSA, pain is a symptom not an impairment, and so must be corroborated by medical signs or laboratory or imaging findings. In addition, chronic pain has been deemed not sufficient to demonstrate a mental impairment. As a result, what is assumed with the AMA guidelines is more overtly stated by the SSA, that disability is causally linked to impairment, and the greater the impairment found, the greater the disability.

An illustration of how the inference from impairment to disability can break down is well illustrated in the spinal cord injury (SCI) population. Up to 75% of SCI patients suffer from chronic pain with the intensity of pain being positively associated with greater disability, greater perceived stress, and lower measures of well-being. This is true despite the fact that greater pain intensity and disability in SCI has been shown to be negatively correlated with the degree of physical impairment as measured by accepted standards.12

We must keep in mind that disability determination is not in any straightforward way based solely on medical factors. Even from state to state the environment in which disability is determined will vary markedly. For example, the court determined percent disability for a man with low back pain will vary on average from 9.4% in New Hampshire to 27% in Tennessee.2 Ultimately, disability is inevitably tied to the incentives, values, and goals of both the patient and the society in which he or she lives.

As can be seen from the previous discussion, the current medical paradigm is not ideally suited for the assessment and determination of disability in patients with chronic pain. The problem is further complicated by the medicolegal construct, in which the identification of disability is meant to be static. Defining a certain level of disability may convey the message to the patient that the rehabilitation effort has ended and will be of no further benefit despite functional limitations that are quite effort-dependent in chronic pain conditions.13 Identification of impairments with a level of disability may erroneously give the patient the idea that the disability is considered fixed, and therefore will weaken the patient’s motivation for recovery. Even in other catastrophic medical illnesses (such as stroke, myocardial infarction, and others) functional recovery, disability, and impairment are based both on the fixed lesions and on factors that are alterable such as patient motivation, family support, cultural and environmental background, and the medical and social commitment of resources to rehabilitation. Hence, a disability determination may be countertherapeutic in a chronic pain patient if it negatively affects these alterable factors.

On the other hand, a disability rating that results in the settlement of a workers’ compensation or a personal liability case may be necessary from a psychological point of view before a chronic pain patient gives his or her full effort to reach maximal functional improvement in a rehabilitation program. In this setting, secondary gain issues, whether conscious or unconscious, may be impeding the positive outcome of rehabilitation.14

In many cases, physicians end up sanctioning or reinforcing disability inappropriately, especially in cases in which the patient complains of pain and functional limitations and there has been a history of major pain-related surgery such as with failed back syndrome. This group of chronic pain patients is at high risk for becoming disabled. The data are abysmal with high re-operation rates (17% to 20% in an industrial setting), and low return to work rates (only 23% to 43% return to work after disk surgery and up to 51% of patients will still be on disability 3 years following spinal fusion). In this setting physicians tend to “over-medicalize” the patient (repeat surgeries, overmedication, repeated invasive injection procedures) in an attempt to relieve pain because the pain report is generally believed, given the history of structural damage. This tends to lead the treating physician to sanction the reported disability of the patient since at least there is “objectively” something wrong with the patient’s spine and none of the applied treatments have diminished the pain.5 However, this inevitable path to permanent disability can be significantly reversed if the patient is given an aggressive functional restoration program that includes behavioral as well as physical treatment. The return to work rates for this group of failed back patients can be as high as 87% despite no change in the structural impairments.15

Disability assessment should be viewed as an attempt to determine the behavior or performance of an individual in a specific context.16 Loss of a specific function such as the inability to bend to pick up a 15-lb box at work may coexist with the ability to bend and pick up a 30-lb, 3-year-old child. This functional dissonance can exist without conscious malingering because of the powerful differences between the absolute inability to perform a task versus the inability to perform a certain task comfortably in a specific environmental context. This makes the differentiation between those who cannot work from those who do not want to work quite difficult. Pain is subjective and is influenced by environmental factors. Impairments and disabilities may fluctuate depending on the situation in which a chronic pain patient finds himself.

There are a wide range of functional assessment methods available, which vary from simple range-of-motion measurements that can be easily performed in the office setting, to sophisticated, 2-day functional capacity evaluations that require expensive equipment and trained personnel. The most commonly used methods are pain measurement tools, functional assessments (by patient report or examination), psychological measurements, and information about the general health status. The use and combination of these different methods depends largely on the goal of the assessment. These goals may be a medicolegal disability rating in a workers’ compensation case, identification of limitations to direct the patient to an appropriate therapy program, or for research purposes. Table 84-1 gives an overview of the different categories and frequently used assessment methods in pain patients. The most widely used measurements are discussed in the following paragraphs.

Pain Intensity

Since pain is a multidimensional experience and is private and subjective in nature, it may be the most difficult measurement to perform in health assessment. Its results often do not follow the basic requirements of psychometric measurement, that is, reliability and validity. Pain measurement can capture two dimensions of the pain experience; namely, the sensory aspects of the pain and the person’s emotional reaction to the pain. Although most clinical applications use fairly simple intensity scales, newer measurement methods are starting to evolve. Based on sensory decision theory, these methods attempt to distinguish the stimulus strength from the subjective response. It has been demonstrated, for example, that a placebo works as an analgesic primarily by reducing the respondent’s tendency to label an experimental stimulus as “painful” rather than by altering the person’s ability to feel it. Thus, the placebo seems to alter the affective response, not the perception of the stimulus.17

Most pain measurement methods can be divided in the following categories: pain questionnaires that record verbal or written responses to pain; behavioral measurements of pain that depend on observed pain behaviors of the subject; and analog methods, commonly used in laboratory studies, in which the respondent compares his pain with an experimentally induced pain stimulus of known intensity.18 However, these different approaches measure different aspects of pain, and there appears to be little correlation between them.

The most commonly known and widely accepted questionnaires are the different subtypes of the visual analog pain rating scales. They provide a simple way to record a subjective estimation of pain intensity. Several types have been used, but the original scale, popularized by Huskisson, consisted of a straight line, 10-cm long, that represented the range of pain to be rated.19 The visual analog scale (VAS) has been studied extensively, showing excellent reliability and adequate validity. In the comparison of different types of pain rating scales, it has been demonstrated that the numerical ratings are preferable to the verbal rating scales. For children and illiterate patients, a version showing faces is available. Overall, the VAS provides a robust, sensitive, and reproducible method of expressing pain severity that is applicable to a wide age range (children age 5 and older to adults that are cognitively intact) and is easily applied in a clinical setting.

Melzack’s McGill Pain Questionnaire (MPQ) is the most commonly used measurement to describe the diverse dimensions of pain. The MPQ was initially presented in 1975 as a preliminary method. However, the questionnaire continues to be used in its original form and is considered the gold standard against which other, newer instruments are compared.18 An attempt to address three major dimensions of pain—sensory-discriminative, motivational-affective, and cognitive-evaluative—are represented on the MPQ. The complete MPQ includes the patient’s history and diagnosis, drug regimen, symptoms, and the effects of pain on the patient. The most commonly used section, however, is the 102-word questionnaire in which the patient has to mark pain attributes (i.e., sharp, burning, lancinating, punishing), pain intensity, accompanying symptoms (i.e., headache, dizziness), sleep, food intake, activity, and time course. It also includes a dermatomal pain drawing.

Four different scoring methods have been described by Melzack. The reliability of the MPQ is only weak, and the validity is adequate. There have been considerable discussions whether the selection and grouping of words reflect the dimensions he proposed.20 Nevertheless, the importance of the MPQ is demonstrated by the incorporation of certain of its sections into several other scales and its use in many study protocols. The questionnaire takes about 15 to 20 minutes to administer, and is therefore probably too long for a routine office visit, but it may be helpful for an initial evaluation.

Functional Impairment

Limitations at the impairment level can be easily measured with the addition of a small number of functionally oriented examination techniques. Determining physical parameters such as range of motion, strength, lifting, and endurance can be incorporated in routine office visits or evaluation protocols and enables numeric documentation of structural impairment. Waddell studied the correlation between physical examination findings and self-reported disability in low back pain patients, demonstrating that total lumbosacral flexion measured at the T12-L1 interspace explained the greatest proportion of variance in disability scores when compared with any other physical examination test performed to assess chronic low back pain.21 Once impairments are identified, treatment can focus on improvement of these functions rather than pain reduction. This becomes increasingly important in chronic pain patients, in which a pain elimination treatment approach is rarely successful.

Inclinometer techniques have become increasingly popular, especially in the physical assessment of back pain patients, since they are easy to apply.22 They have become standard measurements in functional restoration programs for chronic back pain. Total lumbosacral flexion and extension can be assessed by placing a single inclinometer over the T12-L1 spinous processes. Straight leg raising can be tested by using the inclinometer placed on the tibial tuberosity. Suggested normal range of motion values for lumbosacral mobility are a minimum of 100 degrees of flexion and 25 degrees of extension, and for straight leg raising, a minimum of 75 degrees. Recorded measurements can be documented on graphs for quick reference (Fig. 84-2). Initial measurements in pain patients are likely to be influenced by psychological issues as well as physical tolerances, since patients may be inhibited by emotional distress, fear of injury, and pain. Therefore, although measurements may not represent true physiologic abilities, they still provide a numeric measure of the patient’s psychophysical status and a meaningful starting point for treatment decisions.

The testing of strength, lifting, and endurance can be performed in a number of ways. None of the strength measure methods (isometric, isotonic or isokinetic) is superior in this setting, since all provide quantification of strength impairments. One relatively inexpensive method of lower back extension strength testing was developed using a standard back extension unit found in many fitness facilities (Fig. 84-3).23 The testing protocol determines the maximum amount of weight that a subject can lift for four repetitions. Testing weight is begun at 9 kg. The endpoints for the test are psychophysical (subjective maximum), form (poor performance), or safety (more than 120% of the body weight). Based on normative data, the trunk extensor strength for a non-impaired person should be around 100% to 110% of ideal body weight.23 Chronic back pain patients typically have an isometric extension strength that shows an approximate 50% reduction compared with non-impaired persons. Although other measurements of impairments have been described in the literature, this method illustrates the basic concept that the effects of pain on physical performance rather than solely the pain intensity itself should be measured. Similar strategies should be adopted for other pain syndromes not related to the spine.

The role of functional capacity evaluations (FCEs) has considerably increased over the last several years. They are used for work injury prevention and in rehabilitation to define an individual’s functional abilities or limitations. By asking the patient to perform a set of certain test activities, the individual’s ability to meet the required work demands can be assessed. FCEs are increasingly used to determine a patient’s ability to return to his workplace, for pre-employment screening, for disability determinations, and to assist in determining case closure in medicolegal cases.24 Although all systems share the common goal of attempting to measure work-related functional performance objectively, considerable differences in length of assessment, psychometric evaluation, costs, and standardization exist. Research to justify the use of FCEs for disability determination is sparse and the testing measures of consistency should not be inappropriately used to make a determination of possible malingering.

There has been a marked increase in the use of diagnostic imaging over the last 10 years. Recent analysis of the data from the National Low Back Pain Study found that men receiving disability compensation were much more likely to have both computed tomography (CT)-myelogram and magnetic resonance imaging (MRI) when compared with those with a comparable diagnosis who were not receiving compensation.25 One possible explanation is that this overuse of imaging techniques in compensation patients is driven by the goal to find a structural abnormality to justify the degree of reported disability, since either imaging test alone would normally be sufficient to rule out serious injury or need for surgery.

The perception that references to structural abnormalities necessarily increases objectivity in disability assessment is not supported by the literature. There is very poor correlation between objective structural deficits seen with various diagnostic studies and pain or functional loss. In a recent study of MRI findings of the lumbar spine in pain-free individuals, only 36% of asymptomatic individuals had a normal study.26 Up to 70% of asymptomatic individuals have degenerative disk disease demonstrable on plain films.27 The objective function of the spine, as measured by isokinetic trunk muscle strength for patients with chronic low back pain, has been shown to be independent of the degree of degenerative changes seen on CT scans.28 Conversely, the absence of findings on diagnostic testing of a patient with pain does not prove in any way that the pain syndrome lacks a physical cause. There are numerous conditions that have a paucity of objective findings on the diagnostic tests commonly available but, nevertheless, have accepted diagnostic criteria based on clinical examination techniques. Examples include myofascial pain, fibromyalgia, and complex regional pain syndromes. Should we then call all of these conditions behavioral disorders as has been recommended for nonspecific low back pain by the International Association for the Study of Pain (IASP) Task Force on Back Pain in the Workplace?29

Attempts to overcompensate for the lack of clear structural deviations in chronic pain patients by excessive diagnostic testing to find something “objective” only reinforces illness behavior. Even when a test is positive for some abnormality, the anatomic finding may have nothing to do with the functional losses observed, given the low specificity of most tests. Use of less common testing procedures such as thermograms and quantitative sensory testing are even less sensitive and specific and offer no help. In a survey of 80 pain specialist asked to rank the utility of various tests and procedures used to evaluate pain patients in order to develop a weighted ranking, the top seven ranked methods of evaluation were clinical examination procedures: examination of the nervous system, gait, spinal mobility, muscular function, soft tissue, and joint mobility were all ranked higher than any imaging or laboratory test.30 The same authors have developed a total index of pathology (Medical Examination and Diagnostic Information Coding System, MEDICS) using 17 biomedical procedures commonly used to evaluate chronic pain conditions.

The progression from acute to chronic pain can be viewed to occur in three stages31:

• Stage 1: Onset of pain produces individual emotional reaction to pain.
• Stage 2: After pain persists more than 2 to 4 months, there is an increase in the emotional, behavioral, and physical maladaptation to the pain.
• Preexisting psychosocial and socioeconomic factors may weigh heavily at this stage. Increased somatization and symptom magnification is probable for someone who is premorbidly hypochondriacal or who may have conscious or unconscious secondary gains from being disabled.
• Stage 3: Patient adopts a sick role and becomes accustomed to being relieved from normal responsibilities, social obligations, and financial responsibilities.

Attempts to develop a systematic approach to quantifying illness behavior in spine patients have been well established by Waddell (Table 84-2). A high Waddell score is defined as 3/5 positive signs and has been associated with poor performance on functional capacity evaluations, poor outcomes in surgery, and is often used as an indication that a mental health consult is necessary. There is a less clear picture with regard to its prognostic relevance in determining degree of disability. There have been a number of well-designed studies showing that there was no predictive value in using the Waddell signs when looking at return to work, work retention, or post-treatment health care utilization following an intensive functional restoration program.32 Others have found some utility in using the Waddell scores in screening of those who will do well in an intensive work-hardening rehabilitation program that did not have a behavioral treatment component.33

Does compensation status influence disability in pain patients? Table 84-3 illustrates some of the socioeconomic factors that are predictive of disability. The majority of well-designed studies have demonstrated that patients receiving or seeking financial compensation exhibit greater levels of psychological distress and depression, higher levels of pain severity, and perceived disability.14,34,35 In these studies, pain severity and perceived loss of function were independent of physical impairments. Is this all due then to problems of conscious secondary gain? Arguing against this is that these factors do not tend to be predictive of subsequent employment or health care utilization in prospective studies where an appropriate rehabilitation intervention has been applied.36 Following the rehabilitation process, measures such as improved strength and range of motion were correlated with reduced levels of pain and depression in both the compensation and noncompensation groups. In general, a traumatic onset of pain and lack of employment have been associated with higher levels of emotional distress and perceived disability, and are likely playing an independent role in compensation cases.

Unfortunately, both Waddell signs and questions of increased emotional distress with exaggerated ratings of pain severity and disability have been attributed to malingering or conscious secondary gain. This is not, however, a medical determination, and is better left to a court of law. Ultimately, short of a surveillance videotape, we must rely on patient reports of pain and dysfunction and cannot make determinations of conscious falsification of the data based on observed pain behaviors or seemingly exaggerated complaints. Fishbain points out that the concept of secondary gain is confused in any case, and does not help distinguish between true physical pathology from purely psychological pathology since both can have secondary gain issues.37 The reality is that many of the secondary gains, conscious or not, are more than compensated for by the secondary losses related to chronic pain, and thus the lack of utility in using this concept for predicting disability outcome. This is demonstrated by ample case experiences of patients whose cases are finally settled and who will still exhibit continued heightened pain behaviors and signs of emotional distress if not treated for their pain issues. Multiple signs on Waddell testing by Waddell’s own analysis are not a test of credibility or malingering but rather indicate the need for further psychological assessment.38

It is well accepted that a number of psychosocial factors contribute to poor functional outcomes in pain. These include attitudes, beliefs, cultural norms, moods, focus of attention, motivation, and personality traits. Although most chronic pain patients are depressed and anxious, they seldom have a history of long-standing psychiatric problems. Rather, most of their symptoms reflect their current condition. Although chronic pain patients may exhibit certain personality traits that potentially contribute to their inability to cope with a chronic condition, rarely are these traits suggestive of significant psychopathology.39 Certain psychosocial risk factors have been identified that are more likely to result in poor treatment outcomes and the development of disabling pain if left untreated (Table 84-4). In New Zealand, comprehensive guidelines for the treatment of low back pain were designed to assist health care professionals in recognizing these patients early and to ensure timely mental health referrals (Table 84-5).47

Nevertheless, the role of psychological assessment is still poorly understood by many pain specialists. The traditional notion that the lack of an easily identifiable physical or “organic” cause of pain implies that the pain must be psychogenic or “nonorganic” and deserves a mental health referral is erroneous logic. This type of faulty reasoning does the patient and society a disservice at many levels. By embracing such a dualistic view of the body where there is an attempt to compartmentalize the painful sensations reported by a patient either into the body or the mind is wrong both philosophically as well as physiologically and therapeutically. The perception and interpretation of pain is just as important as the nociceptive input. The notion that we can come to a firm conclusion about the objective origins of a pain experience based on diagnostic testing, examination, and/or various diagnostic and therapeutic invasive treatments is not founded on science.26,48 That a patient does not respond to treatment as expected often means we have not taken into sufficient account the myriad of psychosocial, socioeconomic, and physical factors that are influencing the patient’s pain experience. The presence of emotional distress, anxiety, depression, and anger is often present in the chronic pain state, even in the absence of work disability, and does not signify the absence of nociceptive input. Functionally oriented treatment of chronic pain patients even with elevated scores of hypochondriasis, depression, and hysteria as measured by the MMPI, has been shown to be successful, and typically the post-treatment scores on these three scales drop significantly.49 This indicates that it is not a fixed personality trait that predisposes patients to chronic pain but the pain itself that may underlie the emotional distress.

The value of a systematic psychological assessment is to try to determine those factors that, if left untreated, will ultimately lead to prolonged loss of function and disability. In a study of pain severity by Von Korff,50 four grades of disability scores were developed from a population survey of a large HMO in Washington state:

• Grade I: Low Disability score, Low Pain Intensity score
• Grade II: Low Disability score, High Pain Intensity score
• Grade III: Moderately Limiting, High Disability score
• Grade IV: Severely Limiting, High Disability score

The disability score was based on days missed from work over a 6-month period and degree of limitation and pain severity determined by self-report. Pain severity was not included in the grading of grades III and IV since these individuals uniformly reported elevated pain intensity. What is of interest is knowing what the differences were between individuals in the transition from grade II to III. These groups by definition had significant differences in degree of disability (3 days off work versus on average 23 days off work in last 6 months) but no discernible differences in pain scores, persistence of pain, or recency of onset of pain. The largest differences turned on behavioral variables such as reported functional limitations, unemployment status, and health care utilization rather than differences in psychological variables such as depression and health status. Grade IV patients did show significantly higher levels of depression.50 This suggests a gradient of dysfunction in chronic pain, where many individuals may be disabled due to nonadaptive reinforcing patterns of behavior rather than overt emotional distress or psychological impairment. Psychological referral is appropriate both in cases of overt psychopathology and when the problem is more due to dysfunctional patterns of illness behavior.

In clinical practice, a screening method to quantify the three important areas of physical functioning, pain, and psycho-affective well-being is needed. A quick overview of these three areas could help the clinician in prescribing therapies for problems that most significantly affect the patient based on the degree of disability found. One approach, based on Internet technology is the Medical Rehabilitation Follow Along (MRFA). This interactive tool has been designed to assist in patient screening, resource allocation, and outcome assessment for pain patients in the outpatient setting. The MRFA was developed by using major concepts from the Functional Assessment Screening Questionnaire (FASQ), the Oswestry Scale, the short form of the McGill Pain Questionnaire, and the Brief Symptom Inventory.51

The administration of the self-report questionnaire takes approximately 15 minutes and can be filled out prior to every office visit. The scores of eight subcategories are summarized in the areas of physical functioning, pain experience, driving, and affective well-being. With the use of computer technology, the results are available to the treating physician within minutes. This allows the physician to tailor the treatment plan according to the results. The patient’s profile can be compared with other patients from the database, especially during follow-up visits when the effectiveness of a therapy plan is assessed. Differences from a “normal” recovery process are recognized immediately, allowing immediate changes in the treatment strategies. This may permit identification of problematic patients early on in the recovery process, allowing intervention before disability develops from chronic pain.

Another strategy was developed as part of the recognition by the SSA of the growing problem with pain-related disability. The Commission on the Evaluation of Pain was formed, and together with the Institute of Medicine, a predictive tool was developed called the Multiperspective Multidimensional Pain Assessment Protocol (MMPAP). Like the MRFA, the MMPAP combines a number of recognized instruments (the McGill Pain Questionnaire, the Multidimensional Pain Inventory, and the Oswestry Pain Inventory) together with a structured functional assessment by the examining physician to rate patient’s pain behavior, medical status, and rehabilitation potential. The MMPAP has been tested and validated with good interrater reliability when rehabilitation medicine specialists were given training in the use of the tool. Findings support that the individual’s ability to adapt or cope with pain is a significant determinant of disability. The analysis also indicates that functionally oriented physician assessments can be predictive of future disability risk if properly trained (Table 84-6).4

Recent estimates reported in Business Week (March 1, 1999) of the costs for the treatment of pain are now rising to $100 billion dollars a year in the United States with 515 million work days lost each year. Last year, Congress voted to allocate $102 million to the National Institutes of Health for pain research, a 15% jump from the prior year. Despite this, chronic pain continues to grow, and as physicians, we must shift our attention from trying to cure these patients to finding ways of limiting loss of function and disability. To do this, the complex multidimensional nature of pain must be accepted as part of the territory. Physical, psychosocial, and socioeconomic factors must be included in the assessment to avoid being more a part of the problem than part of the solution. We end by offering a minimal guide of the four domains of assessment that should be included in any pain evaluation (Table 84-7).