Comparison of "instrument-associated" and "spontaneous" obstetric depressed skull fractures in a cohort of 68 neonates.

OBJECTIVE: A depressed skull fracture is an inward buckling of the calvarial bones and is referred to as a "ping-pong" fracture. This study aimed to look at differences between "spontaneous" and "instrument-associated" depressed skull fractures.

STUDY DESIGN: This retrospective, case-control analysis included every neonate who was admitted with a depressed skull fracture between 1990 and 2000. Cases after a spontaneous vaginal delivery, elective cesarean delivery, or cesarean delivery that was performed during labor without previous instrument use were classified as "spontaneous" (n = 18 cases). Cases after a delivery in which forceps or a vacuum cup had been used either successfully or unsuccessfully were classified as "instrument-associated" (n = 50 cases). Continuous data were analyzed with 2-tailed unpaired t tests; chi 2 analysis was used for nominal data. A probability value of <.05 was considered statistically significant.

RESULTS: Fifty depressed skull fractures were associated with an instrument delivery, and 18 depressed skull fractures were classified as "spontaneous." The only obstetric parameter that differed significantly between the 2 groups was the length of the active phase. Among the 68 neonates, 15 neonates underwent prolonged second stage, forceps or manual head rotation, or forceps use during elective cesarean delivery. All "instrument-associated" cases were caused by forceps application or sequential instrument use; depressed skull fractures never occurred after isolated vacuum extraction. Every type of forceps was involved. Intracranial lesions were significantly more frequent in the instrument-associated group (30% vs 0%; P = .02). Two infants sustained persistent severe motor disabilities.

CONCLUSION: Depressed skull fractures occur in the setting of spontaneous and operative deliveries, although the incidence is higher in the latter case. Depressed skull fractures that are associated with instrumental deliveries are significantly more likely to be associated with intracranial lesions. Persistent disabilities are rare.