Circumscribed Thinning of the Calvaria - A Long-Term Sequela After Vacuum Extraction Delivery

Abstract

Abstract Background Vacuum extraction deliveries are associated with a number of complications like injuries to the skin, subperiosteal, subgaleal and intracranial hemorrhages. Even skull fractures have been described, but data on persistent changes in the bone structure of the skull like thinning of the calvaria is lacking in the literature. Aims We describe a previously unreported long-term sequela of vacuum extraction delivery. Methods We present a series of 8 children, who were referred because of an irregularity of the cranial surface without other symptoms. The investigations revealed a circumscribed thinning of the calvaria in all 8 cases. Detailed history and the specific clinical findings were crucial in the assessment. Various imaging techniques were used to visualize the lesions and rule out some differential diagnoses. Results All children had undergone a vacuum-assisted delivery. All irregularities of the cranial surface were discovered incidentally. Clinical examination revealed a round (6) or linear (1) channel-shaped indentation of the calvaria in 7 cases. The shape and size of the annular thinning of the calvaria matched devices commonly used in vacuum extraction very well. In one patient, a localized protrusion of the calvaria was investigated, but an indentation more posteriorly was detected in the CT scan. CT scan was performed in 6 patients, in 2, parents refused this examination. In the follow-up, no progression or symptoms was observed in any of the patients. Conclusion Such long-term sequelae after vacuum-assisted delivery have not been reported yet and the underlying mechanism is unclear. In children who present with irregularities of the cranium, an accurate history, including the mode of birth, and detailed clinical examination should be performed. Knowledge about the presented pathology may help to avoid extensive investigations, particularly CT scan. The publication of further cases could help to propagate the circumscribed thinning of the calvaria after vacuum extraction as a distinctive clinical entity.