The A.A review 30 consecutive cases of syringomyelia operated on during the last seven years. Six terminal ventriculostomies (TV) and twenty-seven procedures for foramen magnum decompression (FMD) were performed. All patients of TV group had CT-myelography (CTM) and/or NMR controls at different times after surgery. Clinical results are as follows: 1) of the 6 patients who had TV, only one showed an improvement while five continued to deteriorate and three of them needed a FMD, one a cysto-peritoneal shunt and the last one died from lung cancer. 2) of the 27 patients who had FMD, twenty improved, four were unchanged and three worsened. 3) no surgical deaths occurred in this series. Postoperative NMR monitoring represents an effective non-invasive neuroradiological procedure that allows follow-up of syrinx evolution over the years.