Syringomyelia and its surgical treatment--an analysis of 75 patients.

A consecutive series of 75 patients with syringomyelia is presented, all of whom were treated by cranio-vertebral operations. Attention is drawn to the difficulty in assessing the results of treatment but 56 stabilised or showed modest improvement after surgery. Occluding the central canal appeared to have no greater influence on the progression of the disease than did simple decompression and did have a higher incidence of complications. Upper motor neurone weakness, joint position sense and central neck pain are the features most likely to improve and it is concluded that relieving the medullary compression resulting from a Chiari type 1 malformation, rather than influencing the syrinx, is the means by which this may occur. Simple decompression with preservation of the arachnoid membrane, combined with syringostomy in certain cases, is recommended.