Prescriptive and proscriptive lessons for managing shoulder dystocia: a technical and videographical tutorial

Abstract

This tutorial of the intrapartum management of shoulder dystocia uses drawings and videos of simulated and actual deliveries to illustrate the biomechanical principles of specialized delivery maneuvers and examine missteps associated with brachial plexus injury. It is intended to complement haptic, mannequin-based simulation training. Demonstrative explication of each maneuver is accompanied by specific examples of what not to do. Positive (prescriptive) instruction prioritizes early use of direct fetal manipulation and stresses the importance of determining the alignment of the fetal shoulders by direct palpation, and that the biacromial width should be manually adjusted to an oblique orientation within the pelvis-before application of traction to the fetal head, the biacromial width is manually adjusted to an oblique orientation within the pelvis. Negative (proscriptive) instructions includes the following: to avoid more than usual and/or laterally directed traction, to use episiotomy only as a means to gain access to the posterior shoulder and arm, and to use a 2-step procedure in which a 60-second hands-off period ("do not do anything") is inserted between the emergence of the head and any initial attempts at downward traction to allow for spontaneous rotation of the fetal shoulders. The tutorial presents a stepwise approach focused on the delivering clinician's tasks while including the role of assistive techniques, including McRoberts, Gaskin, and Sims positioning, suprapubic pressure, and episiotomy. Video footage of actual deliveries involving shoulder dystocia and permanent brachial plexus injury demonstrates ambiguities in making the diagnosis of shoulder dystocia, risks of improper traction and torsion of the head, and overreliance on repeating maneuvers that prove initially unsuccessful.

Keywords: brachial plexus injury; maneuvers; negative instruction; positive instruction; simulation; visual didactics.

Figure 1:

In the gynecoid pelvic outlet, as viewed in the transverse plane, the anterior-posterior dimension of the pelvic outlet (measured from the pubic symphysis to the tip of the coccyx) is about 10.5 cm in length. The oblique dimension is about 2 cm wider, measuring on average 12.5 cm in length. The latter dimension best accommodates the fetal shoulder width (biacromial diameter) during normal vaginal delivery.

Figure 2:

A: Sagittal CT of the pelvis in upright position illustrates that the pelvic inlet and pelvic outlet do not lie in parallel planes. B: The cavity of the true pelvis is comparable to bent cylinder. Note the curvature of the pelvic axis. As with the mechanical threads of a screw, which are aligned in skew orientation, a rotational motion at one end produces forward progression.

Figure 2:

A: Sagittal CT of the pelvis in upright position illustrates that the pelvic inlet and pelvic outlet do not lie in parallel planes. B: The cavity of the true pelvis is comparable to bent cylinder. Note the curvature of the pelvic axis. As with the mechanical threads of a screw, which are aligned in skew orientation, a rotational motion at one end produces forward progression.

Figure 3:

In the conduct of normal labor and delivery, the birth attendant should manually check the orientation of the shoulders using direct digital palpation, before applying initial traction on the head. Reprinted with permission.

Figure 4:

This schematic of posterior Rubin’s Maneuver – the 30-degree rotation/adduction of posterior shoulder to align with the oblique diameter of the pelvic inlet demonstrates its mechanical advantage in that it reestablishes the normal physiologic position, which is optimal for unobstructed vaginal delivery.

Figure 5:

A: If the mother is able to support herself, turning to an all-fours position may dislodge or reorient the impacted anterior shoulder; however, the clinician must confirm this with direct palpation or rotation. B: Customary traction with symmetric pressure applied to the head with the mother on all fours delivers the posterior shoulder and thereby releases the obstructed anterior shoulder.

Figure 5:

A: If the mother is able to support herself, turning to an all-fours position may dislodge or reorient the impacted anterior shoulder; however, the clinician must confirm this with direct palpation or rotation. B: Customary traction with symmetric pressure applied to the head with the mother on all fours delivers the posterior shoulder and thereby releases the obstructed anterior shoulder.

Figure 6:

Sims position (as illustrated) may be used similarly to Gaskin’s maneuver when regional anesthesia hampers maternal mobility.

Figure 7:

Presented with a simulated shoulder dystocia in which the fetus would not deliver, obstetrician participants reversed the direction of applied traction to the mannequin head. Reprinted with permission.

Figure 8:

A: A common misstep in beginning internal rotational maneuvers is the clinician inserting her dominant hand, regardless of fetal position. Note the clinician is using her right hand to deliver the posterior (left) arm in this simulated delivery. B: Instead, in a shoulder dystocia where the head in left occiput anterior position and the fetus’ back is on the maternal left, the clinician preparing to deliver the posterior arm or perform a corkscrew maneuver is advised to begin with the left hand as pictured (regardless of hand dominance). Although initially awkward, once the posterior shoulder is rotated in clockwise fashion (adducting the shoulder toward the fetal chest) and the clinician’s arm reaches the 7 o’clock position, she has the full range of motion of the left arm to complete either the sweep of the posterior arm across the chest or the full 180-degree clockwise rotation to the anterior position in front of the pubic bone.

Figure 8:

A: A common misstep in beginning internal rotational maneuvers is the clinician inserting her dominant hand, regardless of fetal position. Note the clinician is using her right hand to deliver the posterior (left) arm in this simulated delivery. B: Instead, in a shoulder dystocia where the head in left occiput anterior position and the fetus’ back is on the maternal left, the clinician preparing to deliver the posterior arm or perform a corkscrew maneuver is advised to begin with the left hand as pictured (regardless of hand dominance). Although initially awkward, once the posterior shoulder is rotated in clockwise fashion (adducting the shoulder toward the fetal chest) and the clinician’s arm reaches the 7 o’clock position, she has the full range of motion of the left arm to complete either the sweep of the posterior arm across the chest or the full 180-degree clockwise rotation to the anterior position in front of the pubic bone.

Figure 9:

Symphysiotomy is a surgical procedure resorted to when catastrophic obstructed labors (e.g., head entrapment in breech deliveries or shoulder dystocia refractory to all other maneuvers) occur in resource-poor settings. A: A urinary catheter is placed in the urethra and one finger of one hand displaces the urethra off midline while the other hand utilizes a scalpel anteriorly and above to incise the ligament between the two pubic rami, B: as shown.

Figure 9:

Symphysiotomy is a surgical procedure resorted to when catastrophic obstructed labors (e.g., head entrapment in breech deliveries or shoulder dystocia refractory to all other maneuvers) occur in resource-poor settings. A: A urinary catheter is placed in the urethra and one finger of one hand displaces the urethra off midline while the other hand utilizes a scalpel anteriorly and above to incise the ligament between the two pubic rami, B: as shown.