Shoulder Dystocia

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Shoulder Dystocia

• Or,
• The heads out what next?
• Christian A. Chisholm, MD
• Division of Maternal-Fetal Medicine

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Objectives

• At the completion of this presentation, the
  participant should be able to
• Define shoulder dystocia (MK)
• Name three risk factors for shoulder dystocia
  (MK, PC)
• List potential complications, both maternal and
  fetal, of shoulder dystocia (MK)
• Describe the maneuvers used to relieve a shoulder
  dystocia (MK, ICS)

3
Definition

• a delivery that requires additional obstetric
  maneuvers following failure of gentle downward
  traction on the fetal head to effect delivery of
  the shoulders.
• ACOG, Practice Bulletin 40 (November 2002)

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Definition

• Prolonged head-to-body expulsion time
• Objectively defined as 60 seconds
• Deliveries with head-to-body interval of gt 60
  seconds more commonly have higher birth weight,
  shoulder dystocia, and low 1 minute Apgar scores
• Beall et al 1998 Spong et al 1995

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Functional Definition

• A delivery in which the shoulders do not follow
  the head as usual, but rather are delayed in
  delivering or require the use of ancillary
  obstetric maneuvers to effect delivery.
• The anterior shoulder may be impacted behind the
  symphysis pubis, or (less commonly) the posterior
  shoulder behind the sacral promontory

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Incidence

• Reported to occur in 0.2-2 of births
• May recur with a higher frequency, but this is
  really unknown
• Many women and clinicians will opt for cesarean
  in the future, especially if there has been a
  fetal injury
• Recurrence rates reported 1-17

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Risk Factors

• Maternal diabetes mellitus
• Fetal macrosomia
• Multiparity
• Post-term pregnancy
• Previous macrosomic infant
• Previous shoulder dystocia

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Macrosomia

• Birth weight in excess of a specific weight,
  usually defined as either 4500 grams (1.5 of
  births) or 4000 grams (10 of births)
• Birth weight gt 4500 grams rate of shoulder
  dystocia is 10-25
• Birth weight gt 4500 grams AND maternal diabetes
  rate of shoulder dystocia is 20-50

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Large for gestational age

• Birth weight that exceeds the 90th centile of a
  standard growth curve, regardless of gestational
  age.
• A baby may be LGA without being macrosomic

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Pathophysiology

• A mismatch between fetal size and maternal
  pelvic capacity
• Positional variations vertical rather than
  oblique orientation of shoulders
• Increased diameter of shoulder girdle
• Subcutaneous fat deposition may be increased in
  infant of diabetic mother especially with
  sub-optimal glucose control

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Anatomy of the Brachial Plexus

• Nerve roots from C5-C8 and T1
• Merge into three trunks
• Superior (C5, C6)
• Middle (C7)
• Inferior (C8, T1)
• Each splits into anterior and posterior divisions

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Anatomy of the Brachial Plexus

• The six divisions regroup into three cords
• Posterior all 3 posterior trunk divisions
  (C5-T1)
• Lateral anterior divisions of upper and middle
  trunks (C5-C7)
• Medial continuation of lower trunk (C8, T1)

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Anatomy of the Brachial Plexus
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Anatomy of the Brachial Plexus
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Brachial Plexus Injuries

• Strain or stretch
• Partial disruption
• Complete avulsion

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Brachial Plexus Injuries

• Injury primarily to lateral trunk (C5,6, 7) leads
  to Erbs palsy adducted shoulder, extended
  elbow, and flexed wrist (waiters tip)
• Injury primarily to the medial trunk (C8, T1)
  leads to Klumpkes palsy paralyzed hand with
  good shoulder and elbow function

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Maternal Complications

• Post-partum hemorrhage occurs in 11
• 4th degree laceration occurs in 3-4

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Into the Delivery Room
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Clinical Management

• Step One Recognize the presence of a shoulder
  dystocia
• Step Two Be sure enough help is present
• Nursing
• Obstetrics
• Pediatrics
• Anesthesiology

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Clinical Management

• Step Three Apply primary maneuvers
• Mc Roberts maneuver
• Oblique suprapubic pressure
• Step Four Apply secondary maneuvers no
  prescribed order
• Rubin Woods screw Posterior arm All-fours
  Clavicular fracture

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Clinical Management

• Step Five (concurrent)
• Repeat steps three and four (different operator?)
• Consider if an episiotomy is needed (intentional
  4th degree?)
• Step Six Apply final (heroic) maneuvers
• Zavanelli symphysiotomy

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Steps One and Two

• The operator determines a shoulder dystocia is
  present
• Personnel needed
• Nursing
• At least two to assist with maneuvers
• One to serve as recorder, as in a code 12
  situation
• Pediatrics full resuscitation readiness

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Steps One and Two

• Personnel (continued)
• Anesthesiology
• Obstetrics
• Attending to supervise and step in as needed
• 2 residents at minimum
• Ideally 2 at perineum
• One to assist with maneuvers (suprapubic
  pressure) away from perineum

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Step Three Primary Maneuvers

• McRoberts maneuver
• Patient positioned with hips at edge of the
  broken-down birthing bed
• Both hips are sharply flexed with knees remaining
  flexed (knees to shoulders)
• Ideally performed by staff, not family, to assure
  it is adequately performed
• No benefit to prophylactic McRoberts

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McRoberts Maneuver
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McRoberts Maneuver

• This maneuver assists delivery by
• Straightening maternal lumbar lordosis
• Rotates symphysis superiorly and anteriorly
• Improving angle between pelvic inlet and
  direction of maximal expulsive force
• Elevates anterior shoulder allowing posterior
  shoulder to descend

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McRoberts Maneuver
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Oblique suprapubic pressure

• Usually applied in concert with McRoberts
  maneuver
• Directed downward and laterally in order to
  effect rotation of the fetal anterior shoulder
  under the symphysis
• Should be applied from the fetal posterior

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Oblique suprapubic pressure
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Step Four Secondary Maneuvers

• There is no conclusive evidence that one maneuver
  is superior to another
• In each patient, the operator must decide which
  maneuver will be most effective
• This is a good time to decide about an episiotomy
  is there room to get your hand in?
• Time to initiate perinatal code (4-2012)

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Woods screw maneuver

• Apply pressure on the clavicle to effect rotation
  of the shoulders out of the vertical orientation
• As fetus rotates, anterior shoulder should pass
  under symphysis
• May be a good choice for a right-handed operator
  when the fetal occiput is oriented to the
  maternal right

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Woods screw maneuver
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Woods screw maneuver

• Potential complication
• Fetal clavicular fracture IN DIRECTION OF APEX OF
  LUNG

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Rubins maneuver

• Apply pressure to the fetal scapula to effect
  rotation of the shoulders out of the vertical
  orientation
• As fetus rotates, anterior shoulder should pass
  under symphysis
• May be a good first choice for a right-handed
  operator when the fetal occiput is directed to
  the maternal left

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Rubins maneuver

• May result in need for less traction and less
  brachial plexus strain than McRoberts maneuver
• Gurewitsch, 2005

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Delivery of Posterior Arm

• The operator inserts a hand into the vagina and
  locates the posterior arm.
• The operator applies pressure in the antecubital
  fossa to flex the elbow across the chest
• The operator grasps the forearm or hand and pulls
  it out of the vagina

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Delivery of Posterior Arm

• The anterior shoulder should pass under the
  symphysis
• Rotation maneuvers (Woods or Rubins) can be
  applied if needed
• This maneuver will tend to be more difficult with
  ones non-dominant hand

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Delivery of Posterior Arm
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Delivery of Posterior Arm

• Potential complications
• Fracture of humerus
• Fracture of clavicle

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Gaskin All Fours Maneuver

• Attributed to midwife Ina May Gaskin
• An option for a patient without anesthesia
• Traction is applied in the opposite direction
  (still toward the floor, but now directed towards
  delivery of the posterior shoulder first)

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Intentional clavicular fracture

• Apply pressure over mid-clavicle in a vector AWAY
  from the lung
• May be difficult to perform
• If successful, may reduce the diameter of the
  shoulder girdle
• Potential complication
• Lung injury

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Still not out?!

• What now???

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Step Five Regroup and Repeat

• Considerations
• Time passed so far?
• Episiotomy?
• Different operator?
• Make OR preparations!

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Step Six Final Steps

• Zavanelli maneuver (cephalic replacement)
• Relax uterus with terbutaline
• Rotate head back to OA (reverse restitution)
• Flex neck
• Upward pressure
• To OR

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Step Six Final Steps

• Symphysiotomy
• Not commonly done when cesarean is available
• Last ditch effort
• Insert Foley catheter
• Use vaginal hand to laterally displace urethra to
  avoid injury
• Incise symphysis through mons pubis

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Do not

• Panic
• Apply any more lateral traction than would be
  applied in an uncomplicated delivery
• Apply fundal pressure may worsen the shoulder
  impaction or even rupture the uterus
• Cut a nuchal cord until after the shoulders are
  released

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Do

• Remain calm
• Communicate well
• Mark time of head delivery
• Consider calling out time in one minute
  increments
• Call for help
• Document clearly and legibly

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Do

• Be sure to debrief as a team after the delivery
  is completed
• Opportunity to analyze situation and critique
  team performance
• Opportunity to be sure documentation is
  consistent
• Who did what becomes very important
• Send cord gases

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Do

• Review with the family exactly what happened and
  answer questions soon after delivery, but
  probably not immediately
• Follow the babys course in the nursery
• Notify Risk Management

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References

• Shoulder Dystocia (Practice Bulletin 40).
  American College of Obstetricians and
  Gynecologists. November 2002.
• Rodis, JF. Management of fetal macrosomia and
  shoulder dystocia. Up to date, v 14.1 last
  updated October 12, 2005.
• Brachial Plexus. Wikipedia, the online
  encyclopedia. http//en.wikipedia.org/wiki/Brachi
  al_plexus Accessed March 21, 2006.
• Beall, MH, et al. Objective definition of
  shoulder dystocia a prospective evaluation. Am J
  Obstet Gynecol 1998179934.
• Spong CY, et al. An objective definition of
  shoulder dystocia prolonged head-to-body
  interval and/or the use of ancillary obstetric
  maneuvers. Obstet Gynecol 199586433
• Gurewitsch ED et al. Comparing McRoberts and
  Rubins maneuvers for initial management of
  shoulder dystocia an objective evaluation. Am J
  Obstet Gynecol 2005192153.