Lambdoid synostosis or positional plagiocephaly – a visual diagnosis?

Aims: Cranial deformity in infants may result from external positional molding or from premature fusion of cranial sutures. Accurate diagnosis is important because treatment is different. Simple positional molding responds to conservative treatment, but craniosynostosis may require neurosurgical intervention. True lambdoid synostosis is a very rare type of craniosynostosis (incidence 2 to 3%) but the main differential diagnosis for positional plagiocephaly.

Is the differentiation of true lambdoid synostosis possible based on clinical presentation only?

Methods: We retrospectively reviewed the clinical presentation of patients presented in our craniofacial center with true lambdoid synostosis in contrast to the children with positional plagiocephaly. Additional investigations as ultrasound or cCT were evaluated.

Results: In seven children, we found lambdoid synostosis (2 bilateral, five unilateral). Sonographic results and surgical findings confirmed the premature fusion of the lambdoid suture in all patients.

The two with bilateral synostosis showed the deformity at birth with symmetric brachycephaly, different horizontal ear position, and no asymmetry of the face. One showed also different vertical ear position.

In the children with unilateral lambdoid synostosis, the deformity was noted at an average age of 1 month, not improving with positioning and/or physiotherapy.

In contrast to the patients with positional plagiocephaly, we found following clinical signs in these five patients: trapezoid head shape (3/5), different horizontal ear position (4/5), in 2 side of inferior position not corresponding to the affected side, as well as asymmetry of the face (5/5) and tilt of the head.(5/5).

Conclusion: Our findings indicate that clinical appearance in patients with lambdoid synostosis is variable. Correct diagnosis is not always possible by clinical presentation only. Main features of lambdoid synostosis are asymmetries of horizontal ear position as well as facial asymmetry and tilt of the head. High-resolution ultrasound is necessary to confirm the suspected diagnosis of lambdoid synostosis.