Brachial Palsy:Prediction & Prevention.

Raphi Pollack, MDCM, FRCSC.

Bikur Cholim Hospital,

Jerusalem.

Outline

• 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

• Complication of birth trauma

• Major cause of neonatal morbidity

• “Fetal-physician” risk

• Accounts for 4.2% of OBS litigation

8

7

9

4

5

6

3

2

1

Roots

Trunks

Cords

Nerves

ANATOMY OF THE BRACHIAL PLEXUS

UlnarMedianRadial

7

8

9

5

Lateral PosteriorMedial

4

6

Upper Middle Lower

1

2

3

Clinical Syndromes

• Erb Palsy– 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

• 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

• 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

• 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

4001- 4500

> 4500

2.4

21

0

5

10

15

20

25

OR

Brachial Palsy & Instrumental Delivery

2.73.7

18.3

0

2

4

6

8

10

12

14

16

18

20

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 ptsnormal

8 pts OBP

Birth Trauma: Recurrence Risk

• 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

• 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

• MacDonald measurement (SFH)

• Maternal estimation

• Sonographic EFW

• All techniques limited

Fetal Macrosomia: Induction of Labor

• 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

InductionExpectancy

Time to delivery (d)-3.2

BW (Gms.)40624132 *

C/S for CPD1918

Shoulder Dystocia56

Brachial Palsy02

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– 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