What’s in a name?
Is it occipital hypoplasia/syringomyelia complex, caudal occipital malformation syndrome (COMS), Chiari type I malformation or Arnold Chiari malformation? In 1891 Hans von Chiari, a pathologist in Prague, described 4 types of abnormality based on autopsy of infants with hydrocephalous that died shortly after birth. In translation, Type 1 was described as “elongation of the cerebellar tonsils and the medial part of the interior cerebellar lobes into conelike projections, which accompany the medulla into the spinal canal”. Arnold’s name was subsequently added, it is rumoured by two of his students, on the basis of a description of single case and for many years the condition was referred to as Arnold-Chiari syndrome. In recent years the trend has been for simplifying the name to Chiari malformation or the more anatomically accurate term “hindbrain descent”. To use the term Chiari type I or Arnold-Chiari malformation to describe the malformation in the CKCS is not strictly correct as the condition in the dog is inconsistent with the historical description, for example dogs don’t have cerebellar tonsils. The term occipital hypoplasia with secondary syringomyelia, although longwinded, does accurately describe the condition and therefore is least likely to result in confusion. In humans, the term Chiari malformation is convenient “shorthand” for a wide range of similar abnormalities distinct from Hans von Chiari’s original description. Therefore if an eponym must be used for the dog condition, Chiari malformation is probably the most appropriate. Perhaps it would be simpler to use initials, for example OH/SM complex!
Reference: Batzdorf, U. Treatment of Syringomyelia Associated with Chiari I malformation in Syringomyelia: Current Concepts and Management eds N Tamaki, U Batzdorf, T Nagashima Springer-Verlag Tokyo 2001 pp 121-123.
Syringomyelia info and links
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