Anesth Prog 37:144-146 1990
Issues Bridging Basic Science and Clinical Science William Maixner,
DDS, PhD,* and Glen Clark, DDS, PhDt *University of North Carolina, Chapel Hill, North Carolina; tUniversity of Califomia, Los Angeles
The differential diagnosis of chronic orofacial pain is an inherently difficult task. The reasons are multifaceted. They relate to deficiencies in current terminology, in diagnostic evaluation procedures, and in definitions of chronic orofacial pain. It should, additionally, be recognized that the pathophysiology and clinical expression of chronic pain and acute pain differ significantly. Work presented at this workshop and elsewhere has shown that both the central and peripheral nervous system exhibit considerable plasticity in response to injury. Many of these changes are dynamic and alter the way sensory information is processed and modulated, such that strict relationships between tissue pathology and sensory experience may no longer exist.
enhance our ability to classify cases and render a differential diagnosis. Development of a biopsychosocial approach with reliable measures will both contribute to diagnostic capabilities and extend the range of testable hypotheses addressing the etiology and pathophysiology of various orofacial sensory-motor disorders producing chronic pain. An important challenge to researchers attempting to bridge the gap between the basic sciences and clinical practice is to identify valid physiological, psychological, behavioral, and sociological measures or indices of chronic orofacial pain. Though it is clear that chronic orofacial pain produces physiological and behavioral changes, the significance of these changes from a diagnostic, pathophysiologic, or treatment outcome viewpoint has not been systematically evaluated. The identification of valid measures of chronic pain in the biomedical, psychophysical, and psychosociological domains is a critical area requiring greater research emphasis. Investigators should be specifically encouraged to identify indices of variables influencing the development and maintenance of chronic orofacial pain. Objective and subjective measures obtained through a history and physical examination are necessary to render a differential diagnosis. In general, the group concurred that the traditional physical examination requires modification to assess such issues as pain intensity, duration, and location as well as a description of the quality of the pain. The development of a valid and reliable short questionnaire which assesses these multiple dimensions of pain experience is encouraged.
BIOPSYCHOSOCIAL APPROACH Recognizing that chronic orofacial pain results from a complex interaction of anatomical, physiological, psychological, and sociological variables, the group agreed that differential diagnosis of chronic orofacial pain requires a systematic and comprehensive assessment of specific physical, psychological, and sociological factors. The biomedical approach, which includes a thorough history, physical examination, and diagnostic work-up, remains an essential feature of differential diagnosis. The frequent lack of correlation between peripheral pathology and pain, however, indicates that the biomedical model alone is not sufficient to provide for case definition or diagnosis in chronic pain conditions. We recommended that differential diagnosis of chronic orofacial pain use information not only from the traditional biomedical model, but also from a broader approach, recognizing the contributions of psychophysiological, behavioral, and psychosocial factors to the underlying pathophysiologies of orofacial pain. The inclusion of reliable and validated measures of these dimensions should
IMAGING TECHNIQUES There was considerable discussion regarding the efficacy of current imaging technologies for assessing underlying joint pathology and dysfunction. No clear agreement was reached regarding the ability of current imaging technologies, such as magnetic resonance imaging (MRI), to assess underlying joint pathology and dysfunction. Moreover, the relationship between anatomical findings as they relate to the magnitude and etiology of chronic orofacial pain remains an open question.
Address correspondence to William Maixner, DDS, PhD, University of North Carolina, School of Dentistry, Campus Box 7450, Chapel Hill, NC 27599. C) 1990 by the American Dental Society of Anesthesiology
ISSN 0003-3006/90/$3.50
144
Maixner and Clark 145
Anesth Prog 37:144-146 1990 A need for standardization of imaging procedures was noted. It is clear that additional research regarding the relationship between anatomical findings and pain intensity is required if imaging technologies are to prove useful in rendering a differential diagnosis. New imaging technologies may also prove useful in assessing fundamental changes in the physical and chemical properties of muscles and joints. This approach may provide useful diagnostic information and may assist in identifying causative factors which contribute to muscle and joint pain. Research in this area is encouraged.
SENSORY TESTING The identification and use of reliable sensory testing procedures that assess sensory capacities across a wide range of sensory modalities will greatly contribute to our ability to render a differential diagnosis. Though not specifically addressed in this workshop, a number of sensory testing procedures currently in use in many clinical research laboratories can be easily adapted to the clinical setting. Even though pain is a subjective experience there are many psychometric procedures that allow for an objective assessment of the magnitude and quality of a patient's chronic pain. With relatively little difficulty, pain threshold, pain tolerance, clinical pain match point, and pain range can be assessed in clinical patients. The perception of nonpainful sensory stimuli (i.e., warm, cold, percepts coded by low threshold mechanoreceptors) can be evaluated and a general profile of the sensory processing capabilities of a chronic pain patient obtained. Differences in temporal and spatial summation, habituation, and sensory experience may prove useful in rendering a differential diagnosis and in identifying both peripheral and central nervous system contributions to various chronic orofacial pain states. To date, most sensory assessment procedures have been designed to assess sensory processing of extraoral structures. A battery of valid sensory procedures that can be used to assess intraoral as well as extraoral sensory function is needed. Data obtained from sensory testing procedures may prove to greatly assist in rendering a diagnosis and providing for objective measures of treatment outcome.
PSYCHOPHYSIOLOGY Within the psychophysiologic domain, skeletal muscle electromyographic activity, autonomic function, neurochemical, immunologic, and neuroendocrine profiles may provide useful diagnostic measures. It is important that the measurement of these physiological parameters be standardized and that test responses of these systems be
evaluated in the absence and presence of personally relevant environmental stressors. An assessment of central nervous system motor outflow patterns, as assessed by
electromyographic procedures, may also provide useful diagnostic information, when the patient's pain has a muscular component. We currently know little about the way environmental stressors (i.e., stimuli that alter homeostatic set point) influence motor outflow patterns in the orofacial region. Research in this area should be encouraged to evaluate whether environmental stressors engage specific orofacial motor responses that may be related to the expression of chronic orofacial pain. Information gained from such studies may 1) lead to the development of useful diagnostic testing procedures, 2) identify important pathophysiologic factors in certain types of orofacial pain and orofacial sensory-motor disorders, and 3) provide objective measures of treatment outcome. Recommendations regarding the identification of specific autonomic, neuroendocrine, neurochemical, and immunological measures to be used as diagnostic indices cannot be provided at this time. It is suggested that work in this area be encouraged, because novel and potentially useful diagnostic procedures may be identified. In addition, research in this area may provide for a better understanding of the pathophysiologies associated with orofacial disorders that produce chronic pain. BEHAVIORAL AND PSYCHOSOCIAL VARIABLES Within the psychosocial-behavioral domain, measures of dysfunction, interpersonal support and coping skills should be assessed. These measures may prove useful in case definition and predicting treatment outcome, especially when combined with other variables derived from the biomedical and psychophysiological domains.
OTHER In addition to the areas of research outlined above, the following questions identify important potential areas for
study. 1. Does chronic orofacial pain result from alterations of the peripheral processing of nociceptive and nonnociceptive information? 2. Does chronic orofacial pain result from an alteration in endogenous pain modulatory systems? 3. Does chronic orofacial pain result from an alteration in the central nervous system processing of sensory information? 4. Do environmental stressors produce specific and selec-
146 Chronic Orofacial Pain Diagnosis: Issues Bridging Basic Science and Clinical Science
tive neurochemical, endocrine, and physiological responses which contribute to the development and maintenance of chronic orofacial pain? 5. What is the neurophysiology/neuroanatomy of referred chronic orofacial pain and how does this relate to clinical findings? In parallel with the development and definition of valid and reliable bio-psycho-social indices of chronic orofacial pain, it is recommended that a multicenter data base be established. Development of a multicenter data base would greatly assist in the development and assessment of alternative case classification schemes for use in differential diagnosis and selection of appropriate treatments. The data to be collected should be derived from methodologies suitable for use in the clinical setting. Development of a multicenter data base could address,
Anesth Prog 37:144-146 1990
and potentially resolve, fundamental issues in case definition, prevalence, and differentiation of normal variation versus pathophysiologic signs and disease. Collected data could be analyzed using multivariate approaches leading to development of algorithms to assist in differential diagnosis. (Similar information gathered in areas related to cardiovascular disease has provided useful insights into case definition (i.e., diagnosis), pathophysiology, and treatment outcome of a variety of cardiovascular disorders.) Two specific recommendations were agreed upon: 1) An additional workshop should be conducted to determine which variables and measures should be incorporated in development of a multicenter data base. 2) Multiple sites should be identified and provided with the necessary resources to collect pertinent data using standardized techniques of data collection.
Issues Bridging Basic Science and Clinical Science William Maixner,
DDS, PhD,* and Glen Clark, DDS, PhDt *University of North Carolina, Chapel Hill, North Carolina; tUniversity of Califomia, Los Angeles
The differential diagnosis of chronic orofacial pain is an inherently difficult task. The reasons are multifaceted. They relate to deficiencies in current terminology, in diagnostic evaluation procedures, and in definitions of chronic orofacial pain. It should, additionally, be recognized that the pathophysiology and clinical expression of chronic pain and acute pain differ significantly. Work presented at this workshop and elsewhere has shown that both the central and peripheral nervous system exhibit considerable plasticity in response to injury. Many of these changes are dynamic and alter the way sensory information is processed and modulated, such that strict relationships between tissue pathology and sensory experience may no longer exist.
enhance our ability to classify cases and render a differential diagnosis. Development of a biopsychosocial approach with reliable measures will both contribute to diagnostic capabilities and extend the range of testable hypotheses addressing the etiology and pathophysiology of various orofacial sensory-motor disorders producing chronic pain. An important challenge to researchers attempting to bridge the gap between the basic sciences and clinical practice is to identify valid physiological, psychological, behavioral, and sociological measures or indices of chronic orofacial pain. Though it is clear that chronic orofacial pain produces physiological and behavioral changes, the significance of these changes from a diagnostic, pathophysiologic, or treatment outcome viewpoint has not been systematically evaluated. The identification of valid measures of chronic pain in the biomedical, psychophysical, and psychosociological domains is a critical area requiring greater research emphasis. Investigators should be specifically encouraged to identify indices of variables influencing the development and maintenance of chronic orofacial pain. Objective and subjective measures obtained through a history and physical examination are necessary to render a differential diagnosis. In general, the group concurred that the traditional physical examination requires modification to assess such issues as pain intensity, duration, and location as well as a description of the quality of the pain. The development of a valid and reliable short questionnaire which assesses these multiple dimensions of pain experience is encouraged.
BIOPSYCHOSOCIAL APPROACH Recognizing that chronic orofacial pain results from a complex interaction of anatomical, physiological, psychological, and sociological variables, the group agreed that differential diagnosis of chronic orofacial pain requires a systematic and comprehensive assessment of specific physical, psychological, and sociological factors. The biomedical approach, which includes a thorough history, physical examination, and diagnostic work-up, remains an essential feature of differential diagnosis. The frequent lack of correlation between peripheral pathology and pain, however, indicates that the biomedical model alone is not sufficient to provide for case definition or diagnosis in chronic pain conditions. We recommended that differential diagnosis of chronic orofacial pain use information not only from the traditional biomedical model, but also from a broader approach, recognizing the contributions of psychophysiological, behavioral, and psychosocial factors to the underlying pathophysiologies of orofacial pain. The inclusion of reliable and validated measures of these dimensions should
IMAGING TECHNIQUES There was considerable discussion regarding the efficacy of current imaging technologies for assessing underlying joint pathology and dysfunction. No clear agreement was reached regarding the ability of current imaging technologies, such as magnetic resonance imaging (MRI), to assess underlying joint pathology and dysfunction. Moreover, the relationship between anatomical findings as they relate to the magnitude and etiology of chronic orofacial pain remains an open question.
Address correspondence to William Maixner, DDS, PhD, University of North Carolina, School of Dentistry, Campus Box 7450, Chapel Hill, NC 27599. C) 1990 by the American Dental Society of Anesthesiology
ISSN 0003-3006/90/$3.50
144
Maixner and Clark 145
Anesth Prog 37:144-146 1990 A need for standardization of imaging procedures was noted. It is clear that additional research regarding the relationship between anatomical findings and pain intensity is required if imaging technologies are to prove useful in rendering a differential diagnosis. New imaging technologies may also prove useful in assessing fundamental changes in the physical and chemical properties of muscles and joints. This approach may provide useful diagnostic information and may assist in identifying causative factors which contribute to muscle and joint pain. Research in this area is encouraged.
SENSORY TESTING The identification and use of reliable sensory testing procedures that assess sensory capacities across a wide range of sensory modalities will greatly contribute to our ability to render a differential diagnosis. Though not specifically addressed in this workshop, a number of sensory testing procedures currently in use in many clinical research laboratories can be easily adapted to the clinical setting. Even though pain is a subjective experience there are many psychometric procedures that allow for an objective assessment of the magnitude and quality of a patient's chronic pain. With relatively little difficulty, pain threshold, pain tolerance, clinical pain match point, and pain range can be assessed in clinical patients. The perception of nonpainful sensory stimuli (i.e., warm, cold, percepts coded by low threshold mechanoreceptors) can be evaluated and a general profile of the sensory processing capabilities of a chronic pain patient obtained. Differences in temporal and spatial summation, habituation, and sensory experience may prove useful in rendering a differential diagnosis and in identifying both peripheral and central nervous system contributions to various chronic orofacial pain states. To date, most sensory assessment procedures have been designed to assess sensory processing of extraoral structures. A battery of valid sensory procedures that can be used to assess intraoral as well as extraoral sensory function is needed. Data obtained from sensory testing procedures may prove to greatly assist in rendering a diagnosis and providing for objective measures of treatment outcome.
PSYCHOPHYSIOLOGY Within the psychophysiologic domain, skeletal muscle electromyographic activity, autonomic function, neurochemical, immunologic, and neuroendocrine profiles may provide useful diagnostic measures. It is important that the measurement of these physiological parameters be standardized and that test responses of these systems be
evaluated in the absence and presence of personally relevant environmental stressors. An assessment of central nervous system motor outflow patterns, as assessed by
electromyographic procedures, may also provide useful diagnostic information, when the patient's pain has a muscular component. We currently know little about the way environmental stressors (i.e., stimuli that alter homeostatic set point) influence motor outflow patterns in the orofacial region. Research in this area should be encouraged to evaluate whether environmental stressors engage specific orofacial motor responses that may be related to the expression of chronic orofacial pain. Information gained from such studies may 1) lead to the development of useful diagnostic testing procedures, 2) identify important pathophysiologic factors in certain types of orofacial pain and orofacial sensory-motor disorders, and 3) provide objective measures of treatment outcome. Recommendations regarding the identification of specific autonomic, neuroendocrine, neurochemical, and immunological measures to be used as diagnostic indices cannot be provided at this time. It is suggested that work in this area be encouraged, because novel and potentially useful diagnostic procedures may be identified. In addition, research in this area may provide for a better understanding of the pathophysiologies associated with orofacial disorders that produce chronic pain. BEHAVIORAL AND PSYCHOSOCIAL VARIABLES Within the psychosocial-behavioral domain, measures of dysfunction, interpersonal support and coping skills should be assessed. These measures may prove useful in case definition and predicting treatment outcome, especially when combined with other variables derived from the biomedical and psychophysiological domains.
OTHER In addition to the areas of research outlined above, the following questions identify important potential areas for
study. 1. Does chronic orofacial pain result from alterations of the peripheral processing of nociceptive and nonnociceptive information? 2. Does chronic orofacial pain result from an alteration in endogenous pain modulatory systems? 3. Does chronic orofacial pain result from an alteration in the central nervous system processing of sensory information? 4. Do environmental stressors produce specific and selec-
146 Chronic Orofacial Pain Diagnosis: Issues Bridging Basic Science and Clinical Science
tive neurochemical, endocrine, and physiological responses which contribute to the development and maintenance of chronic orofacial pain? 5. What is the neurophysiology/neuroanatomy of referred chronic orofacial pain and how does this relate to clinical findings? In parallel with the development and definition of valid and reliable bio-psycho-social indices of chronic orofacial pain, it is recommended that a multicenter data base be established. Development of a multicenter data base would greatly assist in the development and assessment of alternative case classification schemes for use in differential diagnosis and selection of appropriate treatments. The data to be collected should be derived from methodologies suitable for use in the clinical setting. Development of a multicenter data base could address,
Anesth Prog 37:144-146 1990
and potentially resolve, fundamental issues in case definition, prevalence, and differentiation of normal variation versus pathophysiologic signs and disease. Collected data could be analyzed using multivariate approaches leading to development of algorithms to assist in differential diagnosis. (Similar information gathered in areas related to cardiovascular disease has provided useful insights into case definition (i.e., diagnosis), pathophysiology, and treatment outcome of a variety of cardiovascular disorders.) Two specific recommendations were agreed upon: 1) An additional workshop should be conducted to determine which variables and measures should be incorporated in development of a multicenter data base. 2) Multiple sites should be identified and provided with the necessary resources to collect pertinent data using standardized techniques of data collection.
