Cloverleaf Skull

A congenital nonsyndromic abnormality with a characteristic trilobular aspect of the skull.

(Figure)

(Figure)

Kleeblattschädel.

Craniosynostosis occurs in approximately 1:2,100 live births in the general population. Cloverleaf skull (CLS) accounts for less than 1% of cases.

All reported cases have been sporadic.

The abnormally shaped skull is caused by premature ossification of the coronal, sagittal, and lambdoid sutures. The metopic and squamous sutures do not fuse. It has been hypothesized that abnormal development of the periosteal vascular plexus alters the ossification and development of the skull. CLS may occur as an isolated finding, but is more commonly associated with Thanatophoric Dwarfism, Achondrogenesis, and Camptomelic Dysplasia. It is also seen in Acrocephalopolysyndactyly (Carpenter Syndrome), and Acrocephalosyndactyly Syndromes (Apert, Pfeiffer, and Crouzon Syndromes).

Based on the clinical findings of trilobular skull aspect and craniosynostosis in radiologic examinations (conventional radiography, computed tomography scanning, and magnetic resonance imaging).

Neonatal death is frequent. Patients may have mental retardation. On examination, the skull has a trilobed appearance with high forehead, beaked nose, and depressed premaxillary region. Hydrocephalus is common. Raised intracranial pressure is seen in approximately 45% of patients with complex craniosynostoses. Other features involve the eyes (marked proptosis, exophthalmos, corneal ulcerations) and the limbs (elbow ankylosis, dysostosis multiplex, syndactyly of toes and fingers, restricted joint mobility). Abnormal vertebral size has occasionally been reported.

The presence of raised intracranial pressure should be determined. If CLS is part of a syndrome or skeletal dysplasia, the patient should be investigated for features of that condition. Evaluate for difficult airway management.

Patients may have increased intracranial pressure. On the one hand, this situation makes a rapid-sequence induction (increased risk of vomiting) for tracheal intubation with controlled ventilation desirable. On the other hand, maintenance of spontaneous ventilation may be required until the airway has been secured if airway management is expected to be difficult. The final decision depends on the clinical situation. Careful eye protection is required because of increased risk for corneal ulceration secondary to proptosis. Careful intraoperative positioning is needed because of orthopedic features.

Succinylcholine and ketamine should be avoided if possible in the presence of already increased intracranial pressure.

Cloverleaf Skull and Bone Dysplasia: CLS in combination with genital and chest anomalies that could increase respiratory risks.

Kozlowski-Warren-Fisher Syndrome: Lethal form of CLS with genital anomalies and rhizomelic micromelia.