Shoulder Dystocia
Shoulder Dystocia
Abstract & Commentary
By John C. Hobbins, MD, Professor and Chief of Obstetrics and Gynecology, University of Colorado Health Sciences Center, Denver, is Associate Editor for OB/GYN Clinical Alert
Dr. Hobbins reports no financial relationship to this field of study.
Synopsis: In a laboratory model of initial maneuvers for shoulder dystocia, anterior Rubin’s maneuver requires the least traction for delivery and produces the least amount of brachial plexus tension. Further study is needed to validate these results clinically.
Source: Gurewitsch ED, et al. Comparing McRoberts’ and Rubin’s maneuvers for initial management of shoulder dystocia: an objective evaluation. Am J Obstet Gynecol. 2005;192:153-160: Erratum in: Am J Obstet Gynecol. 2005;192:662.
Shoulder dystocia is one of the most stressful situations facing a patient, her fetus, and her provider. In the worst case, it can result in a rare infant death or disability. A problem that occasionally surfaces is brachial palsy, and this, in turn, not infrequently finds its way into the courts.
After the provider has signaled an emergency to everyone on the labor floor, the shoulder dystocia "fire drill," well engrained into any well-prepped obstetrician, is to attempt various sequential maneuvers to get the fetus delivered expeditiously and with a minimum of trauma. High on the temporal list of actions is the McRoberts’ maneuver. This involves encouraging the patient to hyperabduct her thighs while creating gentle traction of the fetal head downward so that the shoulders can be slipped through the somewhat enlarged anterior-posterior (A-P) diameter of the maternal pelvis, created by this maneuver. Gurewitsch and colleagues recently compared the McRoberts’ maneuver with 2 other less well-known techniques, the Rubin anterior and posterior shoulder maneuvers.
These maneuvers were tested on a simulator which included a three-dimensional maternal pelvis, an "instrumental fetal model," a force sensing glove, and a computer-based data acquisition system. The anterior Rubin’s maneuver required gently pushing the anterior shoulder vaginally about 30 degrees away from the fetal occiput. The posterior Rubin’s technique involved applying pressure on the posterior shoulder to rotate the axis of the shoulders towards the occiput. For example, after restitution, if the position of the occiput was LOT, the anterior shoulder would be pushed counter-clockwise with the left vaginal hand and the posterior Rubin’s maneuver would require the operator to use his/her right hand to create clockwise pressure on the posterior shoulder. The experiment was designed to quantify the peak delivery force, the degree of brachial plexus elongation, and the extent of head rotation.
The winner was the anterior Rubin’s maneuver requiring 6.5 lbs. ± 1.8 lbs. of traction force vs 8.8 lbs. ± 2.2 lbs. for the posterior Rubin’s and 16.2 lbs. ± 2.1 lbs. for the McRoberts’ maneuvers. Head rotation was also less with the anterior Rubin’s technique.
Commentary
This study is an example of how a simulating device designed by scientists can hopefully have an important impact on how we practice medicine. Although the typical response to this study would be to say "it needs to be tested prospectively in a clinical setting," let’s be realistic. This group has shown that the anterior (and posterior, for that matter) Rubin’s maneuver has less potential for fetal morbidity than if the operator creates traction on the impacted shoulder when it is in the A-P dimension.
It has been shown that the McRoberts’ maneuver can add up to 1 cm in the A-P diameter to the pelvis.1-5 However, why not combine the 2 concepts: abduct the legs to create more room and turn the shoulders into the oblique plane prior to traction? An increase in the A-P diameter of a circle (or ellipse) should also have an lengthening effect on the oblique diameter of the pelvis.
Currently, the Rubin’s maneuver is not a component of our shoulder dystocia fire drill, but it sure will be.
References
- Gherman RB, et al. Obstetric maneuvers for shoulder dystocia and associated fetal morbidity. Am J Obstet Gynecol. 1998;178:1126-1130.
- McFarland MB, et al. Perinatal outcome and the type and number of maneuvers in shoulder dystocia. Int J Gynaecol Obstet. 1996;55:219-224.
- Gonik B, et al. Objective evaluation of the shoulder dystocia phenomenon: effect of maternal pelvic orientation on force reduction. Obstet Gynecol. 1989;74:44-48.
- Gonik B, et al. An alternate maneuver for management of shoulder dystocia. Am J Obstet Gynecol. 1983;145:882-884.
- Rubin A. Management of shoulder dystocia. JAMA. 1964;189:835-837.
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