What are the primary rotational maneuvers used during a shoulder dystocia?

Rotational Maneuvers for Managing Shoulder Dystocia

The primary rotational maneuvers used during shoulder dystocia are the Woods' screw maneuver and delivery of the posterior arm, which should be implemented after initial maneuvers (McRoberts and suprapubic pressure) fail to resolve the impaction. 1, 2

Initial Management Sequence

• The American College of Obstetricians and Gynecologists recommends starting with the McRoberts maneuver (hyperflexion of the mother's legs tightly to her abdomen) as the first-line intervention for shoulder dystocia 1
• Suprapubic pressure should be applied simultaneously with the McRoberts maneuver to help dislodge the anterior shoulder from behind the pubic symphysis 1, 3
• These first two maneuvers (McRoberts plus suprapubic pressure) successfully resolve approximately 58% of shoulder dystocia cases 3

Rotational Maneuvers (When Initial Maneuvers Fail)

Woods' Screw Maneuver

• The Woods' screw maneuver involves applying pressure to the posterior aspect of the anterior shoulder or the anterior aspect of the posterior shoulder to rotate the shoulders into an oblique position 2
• This rotational technique aims to decrease the bisacromial diameter by turning the shoulders to align with the wider oblique diameter of the pelvis 2, 3
• Woods' screw is typically implemented as a third-line intervention after McRoberts and suprapubic pressure have failed 4, 3

Delivery of the Posterior Arm

• This technique involves reaching into the vagina to locate the posterior arm of the fetus, flexing the elbow, and sweeping the arm across the chest and face to deliver it 2
• Removing the posterior arm effectively reduces the bisacromial diameter, facilitating delivery of the impacted shoulder 2, 3
• This maneuver is often used as the fourth step in the management sequence but may be attempted before or after Woods' screw depending on clinical circumstances 2

Success Rates and Predictive Factors

• The combination of Woods' screw maneuver and/or delivery of the posterior arm is sufficient to resolve almost all remaining cases of shoulder dystocia after McRoberts and suprapubic pressure 3
• Instrumental delivery significantly increases the risk of failed initial maneuvers (McRoberts and suprapubic pressure), with success rates dropping from 47.7% after spontaneous vaginal delivery to only 15.0% after instrumental delivery 5
• The need for rotational maneuvers increases with the severity of the shoulder dystocia 3

Additional Rotational Technique

• The shoulder shrug technique is a newer rotational maneuver that involves shrugging the posterior shoulder and rotating the head-shoulder unit 180 degrees 6
• This technique has been reported to successfully resolve persistent shoulder dystocia cases when other maneuvers have failed 6

Cautions and Complications

• The risk of neonatal injury (brachial plexus injury and fractures) and maternal trauma increases with the number of maneuvers required 3
• Proper execution of rotational maneuvers requires training and practice to minimize trauma 1
• The American Society of Anesthesiologists strongly recommends simulation-based training programs for emergency teams to improve management skills for shoulder dystocia 1

Management Algorithm

1. McRoberts maneuver + suprapubic pressure (first-line) 1, 4
2. If unsuccessful, proceed to Woods' screw maneuver (rotational) 2, 3
3. If still unsuccessful, attempt delivery of the posterior arm 2, 3
4. For persistent cases, consider additional techniques such as the shoulder shrug maneuver 6

Remember that shoulder dystocia is an obstetric emergency requiring prompt action, and the ability to efficiently progress through these maneuvers is essential for minimizing fetal and maternal morbidity 4, 2.