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					Shoulder Dystocia

            Or,
 The head’s out; what next?

      Ahmad Alkathiri
          MD
                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)
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)
Definition

   “Prolonged head-to-body expulsion
    time”
   Objectively defined as 60 seconds
   Deliveries with head-to-body interval
    of > 60 seconds more commonly have
    higher birth weight, shoulder dystocia,
    and low 1 minute Apgar scores
         – Beall et al 1998; Spong et al 1995
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
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%
Risk Factors

   Maternal diabetes mellitus
   Fetal macrosomia
   Multiparity
   Post-term pregnancy
   Previous macrosomic infant
   Previous shoulder dystocia
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 > 4500 grams – rate of
      shoulder dystocia is 10-25%
    – Birth weight > 4500 grams AND maternal
      diabetes – rate of shoulder dystocia is 20-
      50%
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
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
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
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)
Anatomy of the Brachial
Plexus
Anatomy of the Brachial
Plexus
Brachial Plexus Injuries

   Strain or stretch
   Partial disruption
   Complete avulsion
Brachial Plexus Injuries

   Injury primarily to lateral trunk (C5,6,
    7) leads to Erb’s palsy – adducted
    shoulder, extended elbow, and flexed
    wrist (“waiter’s tip”)
   Injury primarily to the medial trunk
    (C8, T1) leads to Klumpke’s palsy –
    paralyzed hand with good shoulder
    and elbow function
Maternal Complications

   Post-partum hemorrhage occurs in
    11%
   4th degree laceration occurs in 3-4%
Into the Delivery Room…
Clinical Management

   Step One: Recognize the presence of a
    shoulder dystocia
   Step Two: Be sure enough help is
    present
    – Nursing
    – Obstetrics
    – Pediatrics
    – Anesthesiology
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
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
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
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
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
McRoberts Maneuver
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
McRoberts Maneuver
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
Oblique suprapubic
pressure
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)
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
Woods screw maneuver
Woods screw maneuver

   Potential complication:
    – Fetal clavicular fracture IN DIRECTION
      OF APEX OF LUNG
Rubin’s 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
Rubin’s maneuver

   May result in need for less traction and
    less brachial plexus strain than
    McRoberts maneuver
         – Gurewitsch, 2005
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
Delivery of Posterior Arm

   The anterior shoulder should pass
    under the symphysis
   Rotation maneuvers (Woods or
    Rubin’s) can be applied if needed
   This maneuver will tend to be more
    difficult with one’s non-dominant hand
Delivery of Posterior Arm
Delivery of Posterior Arm

   Potential complications
    – Fracture of humerus
    – Fracture of clavicle
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)
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
Still not out?!
  What now???
Step Five – Regroup and
Repeat
   Considerations:
   Time passed so far?
   Episiotomy?
   Different operator?
   Make OR preparations!
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
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
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
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
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
Do:

   Review with the family exactly what
    happened and answer questions –
    soon after delivery, but probably not
    immediately
   Follow the baby’s course in the
    nursery
   Notify Risk Management
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/Brachial_plexus Accessed March 21,
    2006.
   Beall, MH, et al. Objective definition of shoulder dystocia: a
    prospective evaluation. Am J Obstet Gynecol 1998;179:934.
   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 1995;86:433
   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.

				
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posted:11/8/2011
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