Cloverleaf skull--a severe form of Crouzon's syndrome: a new concept in aetiology.

This is a study of 6 patients of cloverleaf skull (CLS) who were treated between 1980 and 1988. All of them had mild to severe degree of craniofacial dysostosis of Crouzon type with variable degrees of exorbitism (pseudoexophthalmus), raised intracranial pressure and mental retardation. All except one patient had maternal H O fever and/or drug intake during the first trimester or toxaemia of pregnancy. The skull X-ray showed typical CLS with expanded middle cranial fossa, foreshortened anterior and posterior fossae and honey-comb appearance in the occiput. Preoperative CT scan revealed generalized hydrocephalus in older patients but only cystic dilatation of the temporal horns in younger infants. The best treatment results were observed in the youngest infant, 7 weeks old, following morcellation cranioplasty, duroplasty, orbital decompression and delayed V.P. Shunt. Fronto-orbital advancement procedure gave satisfactory results in older infants except in those with severe craniofacial stenosis. A delayed CSF shunt is only indicated for progressive postoperative hydrocephalus. Immediate survival was 100% and late 50%. The deaths were due to complications of hydrocephalus. Survival was better in those having less severe Crouzon Syndrome irrespective of the type of surgical treatment. However, timely CSF shunt surgery played an important role in the long term survival, improvement of I.Q., and ultimate shape of head. The study suggests that CLS is a severe malformation of Crouzons disease due to teratogenic damage in the first trimester of pregnancy causing developmental aberration of primary mesenchyme of the neurocranial capsule and base of the skull. The cystic dilatation of the temporal horns is the earliest sign of hydrocephalus and occurs secondary to disturbed growth of the cerebral capsule.