True unilateral lambdoid synostosis is a very rare type of craniosynostosis. Patients present with unilateral posterior plagiocephaly. The differentiation between frequent, simple positional (deformational) posterior plagiocephaly and lambdoid synostosis is not easy and to date subject of controversy. Accurate and early diagnosis is important, because treatment is different. Simple positional plagiocephaly responds to conservative treatment, but craniosynostosis may require neurosurgical intervention. We analyzed clinical presentation of five patients in whom non-syndromic lambdoid synostosis was confirmed by CT imaging, in one additionally by high-resolution ultrasound, and finally neurosurgical intervention. However, clinical inspection alone did not reliably identify infants with lambdoid synostosis.
Conclusion: Diagnosis of lambdoid synostosis is not always possible based on clinical inspection alone. To confirm the diagnosis imaging is recommended. There is evidence that high-resolution ultrasound can be used first-line in the future.