Effect of clinician-applied maneuvers on brachial plexus stretch during a shoulder dystocia event: investigation using a computer simulation model

Abstract

Objective: The objective of the study was to determine how standard shoulder dystocia maneuvers affect delivery force and brachial plexus stretch.

Study design: A 3-dimensional computer model of shoulder dystocia was developed, including both a fetus and a maternal pelvis. Application of suprapubic pressure, rotation of the infant's shoulders, and delivery of the posterior arm following shoulder dystocia were each modeled, and delivery force and brachial plexus stretch were predicted.

Results: Compared with lithotomy alone, all maneuvers reduced both the required delivery force and brachial plexus stretch. The greatest effect was seen with delivery of the posterior arm, which showed a 71% decrease in anterior nerve stretch (3.9% vs 13.5%) and an 80% decrease in delivery force.

Conclusion: The standard maneuvers met the objective of reducing the necessary delivery force compared with the lithotomy position alone. Brachial plexus stretch is also reduced when these maneuvers are used rather than continuing the delivery in lithotomy position.