Results

The descriptor “reflex sympathetic dystrophy” was detected in 576 references, “algodystrophy” in 54, “transient osteoporosis” in 42, “complex regional pain syndrome type I” in 24, “Sudeck” in 16, and “shoulder-hand syndrome” in 11 (table 1). One hundred records were obtained for the descriptor “causalgia” and five for the descriptor “complex regional pain syndrome type II”. Some authors used the terms “type 1 and 2” instead of “type I and II”, and records using both terminologies can be found. The descriptor “complex regional pain syndrome”, without type, detects more records than the combination of complex regional pain syndrome type I and type II (table 1); this might be caused by the trend for several authors to use the term complex regional pain syndrome merely as a synonym for RSD. The descriptor CRPS (abbreviated form and without type) was considered imprecise, because articles not related were obtained (cysteine-rich protein, C reactive protein, C receptor protein, coordinated research projects, cardiac rehabilitation programmes, collagen related peptides, etc).

When we considered the presence of the different terms in the title (table 1, parentheses), the descriptor “reflex sympathetic dystrophy” was detected in 262 references, “algodystrophy” in 29, “transient osteoporosis” in 29, “complex regional pain syndrome type I” in 15, “Sudeck” in 3, “shoulder-hand syndrome” in 5, causalgia in 17, and “complex regional pain syndrome type II” in 3 references.

The term RSD was used by authors from many countries, mainly English speaking authors (table 2), and from different medical specialties and journals (table 3). The term algodystrophy was used by European authors, especially French and Polish authors (table 2), who were mainly orthopaedic surgeons, rheumatologists, internists, and radiologists. The term transient osteoporosis was found in orthopaedic, radiology, and rheumatology journals, but not in pain and neurology journals (table 3). The term Sudeck atrophy was used only by European authors, especially German ones (table 2), who mainly were orthopaedic surgeons. The new terminology, CRPS types I and II, was found in papers written in English, mainly from the United States and Netherlands (table 2) and was especially used by pain and neurology specialists in pain and neurology journals (table 3). Causalgia was also more used by English speaking and Dutch authors (table2).

Discussion

Involvement of the sympathetic system seems unlikely in RSD.5 ,6 To replace this imprecise term the IASP proposed an “umbrella” terminology which does not make any reference to the cause of this entity. Although there is from 1995 up to 1999 a constant increase in its use, the new terminology has not been extensively accepted in the medical literature. Our study shows that the old terms are much more used than the new ones. Overall, there have not been important changes and the most used term is “reflex sympathetic dystrophy”.

It is difficult to change the name of an entity which has been widely used. Although the old nomenclature does not define the syndrome well, there are historical reasons to keep up these old names. A good reason for the change might be that the new terminology and the “draft criteria” are much more precise, but this does not seem to be the case as the term CRPS is too vague.7 ,8 Alternative explanations for the infrequent use of CRPS might be the fact that some authors were not aware of the conclusions of the working group of the IASP and of the existence of this new terminology, which was published in pain journals and not in orthopaedic or rheumatology journals; and the fact that authors, reviewers, or editors were reluctant to substitute CRPS for older terminologies because they feared that most readers of these journals were unaware its meaning.

A clear contribution of the new terminology is the definition of CRPS type II (causalgia), which requires a peripheral nerve injury; however, several authors who used the new term in their papers did not discriminate between the two types and used CRPS terminology, without type, as a synonym for RSD.

We conclude that the new terminology has not effectively replaced the old. RSD and causalgia are still the most commonly used denominations. The CRPS terminology is mainly used in pain and neurology journals. A more extensive international consensus could be useful to unify terminology for these common disorders.