Complex Regional Pain Syndrome. Edited by R. Norman Harden, Ralf Baron, Wilfrid Jänig. Seattle, IASP Press, 2001. Pages: 338. Price: $78.00.
This book presents the findings of independent researchers who were invited to participate in the 2000 International Association for the Study of Pain (IASP) Research Symposium on Complex Regional Pain Syndrome (CRPS). Each investigator provided a synthesis of related work within his or her respective field to a multidisciplinary audience in order to promote new concepts and to formulate an improved understanding of the disease.
The organization of the book mirrors the organization of the conference. As such, the book is divided into three major sections. The first section describes relevant animal models of pain and highlights new understandings of CRPS derived from preclinical investigation. The second section is devoted to human experimentation, and the third is devoted to issues surrounding diagnosis. In addition, there is an informative prologue that provides crucial background information and a brief epilogue that identifies future challenges and areas of anticipated research.
Part two (chapters 2–6) consists of reviews by prominent basic science researchers on mechanistic studies in animal models of neuropathic pain. The chapters by Dr. Chung and that by Drs. Habler and Jänig highlight the ongoing controversy regarding whether the spinal nerve ligation model in the rat is a model of sympathetically maintained pain. The chapter by Vatine et al. suggests that genetic and dietary factors may explain, in part, the discrepancies in the studies from different laboratories. Ringkamp and Wu present evidence that injury to a single spinal nerve results in changes in neighboring uninjured primary afferent fibers that may play a role in the maintenance of central changes after nerve injury. The final chapter in this section discusses the discrepancies between the pain behavior observed in animal models and the clinical presentations in patients with CRPS and suggests that better integration of basic science and clinical research is needed to improve our understanding of this disease.
Part three (chapters 7–18), a section entitled “Human Experimentation,” provides current research updates on several aspects of the clinical presentation of CRPS, reviews the usefulness of models for studying the mechanisms of pain in CRPS, and discusses the clinical evidence for the role of peripheral inflammatory and central sensory disturbances in the pathophysiology of CRPS. The chapters include a summary of well-conducted studies by German and Australian investigators that indicate that functional changes in sympathetic activity and/or changes in adrenergic receptor density or affinity may contribute to the pain and vascular disturbances associated with CRPS. Additional chapters describe the alterations in motor function in CRPS and suggest that impaired integration of visual and sensory afferent inputs to the parietal cortex or disuse may be responsible for the motor abnormalities. Drs. Baron and Jänig end the section with a plea for closer alignment between animal models, human models, and clinical investigations, as current animal models do not mimic the total picture of CRPS.
Part four consists of six chapters related to the diagnosis of CPRS and includes a discussion on the reliability of assessments of swelling and motor function in CRPS and the role of psychologic evaluation and regional anesthesia in the management of these patients. Drs. Bruehl and Harden have written a provocative chapter in this section on their validation studies of the IASP diagnostic criteria, which indicate that the present criteria, although sensitive, may lead to over diagnosis due to poor specificity. A revision of the diagnostic criteria is suggested to help identify more homogenous patient samples for therapeutic trials.
This book is somewhat different from the original text commissioned in 1996 by the IASP on this very topic. The first noticeable difference is that the new book utilizes the now commonly accepted term, CRPS, rather than the outdated term, reflex sympathetic dystrophy. In addition, this book is organized into individual sections that expand on topics briefly covered in the first book. These major sections provide a more cohesive overview of the recent advances, and a chapter that effectively summarizes the preceding section before the reader moves on to the next concludes each of the major sections. Topics not separately covered in the first edition but now included in the 2001 text include brain neuroimaging techniques and genetic considerations, to name a few. In addition, there are several chapters devoted to motor imbalance, with a special emphasis on dysfunction of sensorimotor integration.
In general, the goals of this book are to summarize the recent advances and emerging concepts derived from animal and human experimentation and to emphasize new concepts regarding the diagnosis of CRPS. The book is intended for the clinician and scientist who want a concise overview of the latest progress and scientific discoveries regarding this disease. The print is easy to read, and the text is published on quality paper, with a secure binding. The proofreading and editing are done professionally. The entire book is well written, and individual chapters are referenced appropriately. Several chapters include figures that either illustrate important experimental data or reinforce material presented in the text.
Quite appropriately, the book begins with a wonderful preface that includes a reference to a familiar Indian folk tale:“Young researchers and veteran faculty members alike believed in the preeminent value of their own work in pursuing an understanding of the syndrome. However, when all the pieces were laid out and examined as a whole, it was obvious that we had been functioning like blind men examining the elephant: we understood and believed in our own piece, but we could not conceptualize the big picture.” Although merely a metaphor, this theme haunts us as we read through the individual chapters that comprise the text. At the conclusion of the book, we are left somewhat unsatisfied by the lack of obvious connectivity between the individual topics, despite feeling particularly edified for having completed the text.
The editors themselves acknowledge this dilemma in the epilogue:“Our current store of knowledge is largely an unassimilated collection of facts of unknown clinical relevance. This information must be sorted into some sort of coherent picture.” This lack of coherent understanding is no fault of the book itself, as it effectively summarizes all of the available information that just so happens to be incomplete. In general, the book leaves us hopeful that emerging concepts in disease recognition and a better understanding of pathophysiologic mechanisms and pharmacologic treatments will translate into better patient care. Moreover, we are refreshed by the approach in this book to discard historical concepts that have impeded our understanding of disease and the encouragement to embrace new discoveries and to determine their proper place in our improved understanding.
In all likelihood, readers can anticipate yet another text devoted to this subject in the near future. In the meantime, we strongly recommend this book for clinicians and researchers who yearn for an updated synthesis of scientific advancements regarding CRPS. It is recommended reading for the pain specialist and is worthy of a place on his or her bookshelf.
