Brachial Palsy:
Prediction & Prevention.
Raphi Pollack, MDCM, FRCSC.
Bikur Cholim Hospital,
Jerusalem.
Outline
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History
Natural history
Risk Factors
Prevention strategies
Conclusions
History
 Smellie 1764
 Erb 1874 “delivery paralysis” related to
“moderately energetic manipulation by the
obstetrician”
Significance of Brachial Palsy
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•
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Complication of birth trauma
Major cause of neonatal morbidity
“Fetal-physician” risk
Accounts for 4.2% of OBS litigation
ANATOMY OF THE BRACHIAL PLEXUS
1
2
3
4
5
Roots
6
9
8
Trunks
7
Cords
Nerves
1
2
3
Upper
Middle
Lower
4
5
6
Lateral
Posterior
Medial
7
8
9
Ulnar
Median
Radial
Clinical Syndromes
• Erb Palsy
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C5, C6 root avulsion
Upper trunk plexopathy
Arm Adduction & internal rotation
Elbow extended & forearm pronated
“Waiters tip” position
+/- Horner syndrome
Clinical Syndromes
• Flail arm
– Injury to entire plexus
• Klumpke palsy
– Lower trunk (C8, T1) injury
– Poor grasp, proximal function preserved
Electrodiagnosis
• Nerve conduction studies
– Changes in amplitude of motor & sensory response
• Electromyography
– Study of motor unit potential
• Technically difficult in the neonate
• Insights into pathogenesis
Electrodiagnosis:
Timing of Injury
• Fibrillations
• Onset = 12-21 days
• Peak = 35 days
• Conduction abnormalities : Sensory
• Onset = 5-6 days
• Peak = 10 days
• Conduction abnormalities : Motor
– Onset = 2-4 days
– Peak = 7 days
Incidence of Brachial Palsy
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0.5-3 per 1000 births
Gilbert et al (1995) 1.5/1000 births
5420 cases annually in USA
180 cases annually in Israel
Natural History
• Important to understand burden of disease
– Contrast with clavicular #
• Resolution – how often ?
– Michelow HSC (1994) 92% resolved
– Bager (1997) 49% resolved
• 22% severely impaired
– Eng (1996) 22% resolved
• 78% long term disabilities
Pathogenesis
Excessive downward traction.
Vs.
In-utero insult.
In- utero insult
• Koenigsberger (1980)
– EMG evidence of prenatal injury
• Dunn & Engle (1985)
– Bicornuate uterus
– Bb skeletal deformities, muscle atrophy,
brachial palsy
– EMG findings
In-utero insult : The Evidence
• 1,611 cases of OBP
• 47% of all OBP do not involve shoulder
dystocia
• 60/1,611 cases of OBP Cesarean delivery
• Ascertainment bias ??
• Excessive traction at time of CS ??
Gilbert (1999)
In-utero insult : Natural History
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Gherman (1998) 40 cases of OBP.
OBP in absence of SD : high persistence.
OBP in presence of SD : low persistence.
Suggests pathogenetic heterogeneity.
Brachial Palsy: Risk Factors
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Shoulder dystocia (OR=76.1)
Neonatal birthweight
Instrumental vaginal delivery
Breech presentation (OR=5.6)
Gestational DM (OR=1.9)
Prior infant with brachial palsy
Brachial Palsy & Neonatal BW
OR
.
>
Brachial Palsy & Instrumental
Delivery
.
OR
.
Vacuum
.
LFD
MFD
Highest Risk of Brachial Palsy
Maternal Diabetes Mellitus
&
BW > 4500 Gms.
&
Instrumental Vaginal Delivery
OR = 52
Pts. At Highest Risk for OBP
100 pts
92 pts
normal
8 pts
OBP
Birth Trauma: Recurrence Risk
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Baskett (1995)
Shoulder dystocia over 10 yrs. (N=254)
Recurrent shoulder dystocia = 1/93 (1.1%)
0/8 cases of OBP in setting of prior OBP
Al-Qattan (1996)
16/49 (33%) cases of recurrent OBP
OBP: Negative associations
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Prematurity (OR = 0.8)
IUGR (OR = 0.9)
Cesarean delivery (OR = 0.2)
No factors were entirely protective
Prevention Strategies
• Manipulation of BW
– Tight control in DM
• Risk stratification
– Identification of the macrosomic fetus
– Elective induction
– Elective Cesarean delivery
Murphy’s Law: First Corollary
“Nothing is as simple as it first seems”
Prevention Strategies
• Must be broad based.
• Most OBP cases are not predictable.
– BW < 4000 Gms.
– Not associated with DM.
• Perlow (1996) 19% of OBP predictable.
• Skillful management of shoulder dystocia.
Fetal Macrosomia: Diagnosis
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MacDonald measurement (SFH)
Maternal estimation
Sonographic EFW
All techniques limited
Fetal Macrosomia:
Induction of Labor
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Inclusion EFW > 4000 Gms. @ 38 wks.
RCT.
Induction (N=134).
Expectancy (N=139).
Power to detect 15% change in CS rate.
Gonen 1997.
Fetal Macrosomia:
Induction of Labor
Induction Expectancy
Time to delivery (d) -
3.2
BW (Gms.)
4062
4132 *
C/S for CPD
19
18
Shoulder Dystocia
5
6
Brachial Palsy
0
2
Fetal Macrosomia:
Elective Cesarean Delivery
• Decision analysis model.
• Three policies compared.
– No sonographic EFW.
– C/S for EFW > 4000 Gms.
– C/S for EFW > 4500 Gms.
Rouse 1996.
Fetal Macrosomia:
Elective Cesarean Delivery
Intervention
# C/S
performed / OBP
prevented
Cost /
OBP prevented
C/S for EFW >
4000 Gms.
2,345
$4,900,000
C/S for EFW >
4500 Gms.
3,695
$8,700,000
Fetal Macrosomia:
Elective Cesarean Delivery
• 4000 Gms. Threshold
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Would increase C/S rate by 50%
Reduces OBP by 31%
Costs $4,900,00 per OBP prevented
Leads to 1 maternal death per 3.2 OBP cases
prevented
– Cannot be justified medically or economically
Rouse, 1996
Conclusions
• Beware of macrosomic infants
• Avoid midpelvic deliveries in macrosomics
& GDMs
• Manage Shoulder Dystocia
– Don’t rush
– Avoid excessive traction
Practical Advice
Avoid poor judgment…
Judgment comes from experience…
Experience comes from poor judgment.
Jeanty