Positional plagiocephaly

Clinical History

A 4-month-old girl in good general health was referred to the paediatrician because of a misshapen head.

Imaging Findings

Clinical examination revealed marked flattening of the infant’s occiput which was more pronounced at the left. Positional plagiocephaly was suspected because of the associated preferential head tilt to the left and limited passive head rotation to the right. Radiographs of the skull confirmed flattening of the occiput and failed to show prematurely fused sutures, findings suggestive of positional (or non-synostotic deformational) plagiocephaly.

Discussion

Positional plagiocephaly is a condition in which calvarial deformation results from external pressure after birth when an infant is consistently placed in the same position for rest and sleep. The term ‘plagiocephaly’ derives from the Greek plagios, meaning ‘oblique’ or ‘slanting’ and cephalos, meaning ‘head’. In 1992, the American Academy of Pediatrics recommended that neonates and infants be placed to sleep on their backs in order to decrease the incidence of sudden infant death syndrome. Since then, posterior positional plagiocephaly has become increasingly common.
Distinguishing posterior deformational plagiocephaly from unilateral lamdoid synostosis is critical. True lamdoid fusion occurs in only 2-3% of patients with posterior plagiocephaly and requires complex surgery, whereas posterior deformational plagiocephaly responds well to conservative treatment. In unusual cases or in patients with a high likelihood of having unilateral lamdoid synostosis, CT with volume reformation should be performed. On axial images and volume reformations, detection of an area of osseous fusion of the lamdoid suture is diagnostic of lamdoid synostosis. A short segment fusion however, can be missed on axial views. On volume reformations, several discriminators become evident, as the shape of the head on the posterior view, vertex view, and endocranial skull base view differs significantly between positional plagiocephaly and unilateral lamdoid synostosis. On these views, it can be appreciated that unilateral lamdoid fusion leads to an ipsilateral skull base cant, "twisting" of the posterior fossa, and trapezoidal distorsion of the calvarium.
In the majority of cases of deformational plagiocephaly, positional therapy can effectively resolve the infant’s condition. However, if this approach does not work, helmet or band therapy may be recommended.

Differential Diagnosis List

Final Diagnosis

Posterior (or occipital) positional (or deformational) plagiocephaly

URL:	https://www.eurorad.org/case/7680
DOI:	10.1594/EURORAD/CASE.7680
ISSN:	1563-4086