The clinical and surgical feature in 40 patients with primary cerebellar ectopia (adult Chiari malformation).

This paper reports 40 patients with primary cerebellar ectopia investigated in the University of Manchester departments of neurology and neurosurgery over the five years, 1968-1973. A review of the clinical and surgical findings showed that (a) pain of varying type was the most common symptom, (b) four main clinical groups could be recognized--syringomyelia, paraparesis, cerebellar syndrome and 'raised pressure' syndrome and (c) surgical decompression of the posterior fossa and upper cervical spine resulted in improvement in over 70 per cent of patients with a small incidence of post-operative complications. It should be emphasised that primary cerebellar ectopia is not uncommon and is an important syndrome in its own right. It is often not accompanied by syringomyelia and in these patients the diagnosis can be difficult without supine myelography.