Neurologic complications

Neurologic complications
- whom to blame ?
Benno Rehberg
Médecin adjoint agrégé
Unité d’anesthésiologie gynéco-obstétricale, HUG
SAOA spring meeting 2015
The simple surgical answer:
outline
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Epidemiology
Mechanisms
Prognosis
Work-up
Not included:
- Local anesthetic toxicity
- Transient neurologic symptoms due to hyperbaric solutions
EPIDEMIOLOGY
– LET THE NUMBERS SPEAK
Rising liability claims of neurologic
injury in obstetric anesthesia
Paraplegia:
4 epidural hematoma
4 epidural abscess
2 direct spinal cord injections
1 anterior spinal artery syndrome
Davies, J. M et al: Liability associated with obstetric anesthesia: a closed claims analysis. Anesthesiology 110, 131–139 (2009).
What is the real risk?
1 / 100
Incidence of postpartum
neuropathy 1/100
Wong, C. A. Obstet
Gynecol 101, 279–288
(2003).
Incidence of radiculopathy
after spinal or epidural
anesthesia: 2-4/10.000
Brull, R., et al: Anesth.
Analg. 104, 965–974
(2007).
Incidence of permanent
harm after neuraxial block
in obstetrics: 1.2/100.000
Cook T et al: Br J
Anaesth 102, 179–
190 (2009)
1 / 1.000
1 / 10.000
1 / 100.000
Incidence of postpartum lumbosacral spine
and lower extremity nerve injuries
• Prospective study spanning 1 year (1997-98):
6057 patients
• Question at day 1 after delivery:
«Do you have any leg numbness or weakness?»
• n= 6048
• If positive answer, neurological examination
by a physiatrist
Wong, C. A. et al. Incidence of postpartum lumbosacral
spine and lower extremity nerve injuries. Obstet Gynecol
101, 279–288 (2003).
Incidence of postpartum lumbosacral spine
and lower extremity nerve injuries
Elective C-section
Wong, C. A. et al. Incidence of postpartum lumbosacral
spine and lower extremity nerve injuries. Obstet Gynecol
101, 279–288 (2003).
Risk factors for postpartum
neurological injury
• Nulliparity
• Prolonged second stage of labor
= odds
ratio
suspected = clinical examination or other studies not available
Wong, C. A. et al. Incidence of postpartum lumbosacral
spine and lower extremity nerve injuries. Obstet Gynecol
101, 279–288 (2003).
Which type of injury is common?
n = 6048
Wong, C. A. et al. Incidence of postpartum lumbosacral
spine and lower extremity nerve injuries. Obstet Gynecol
101, 279–288 (2003).
MECHANISMS
OF OBSTRETIC NERVE INJURY
- WHAT HAPPENS IN 95% OF CASES
Mechanism of lesion:
Lateral femoral cutaneous nerve
• Compression against
the inguinal ligament
– During pregnancy (after
30 weeks)
– Prolonged hip flexion
– Due to retraction during
c-section
• Diabetes is a risk factor
(for all nerve compression
injuries)
Lateral femoral cutaneous nerve
Innervation
sensory
motor
«meralgia
paresthetica»:
numbness
paresthesia
-----
Mechanism of lesion:
Femoral nerve
• Compression against the
inguinal ligament
L2, L3, L4
– During thigh flexion,
external rotation and
abduction (position for
pushing)
• Nerve entrapment in the
psoas muscle
• Compression of the
saphenous nerve at the
knee
Femoral nerve
Innervation
sensory
L2, L3, L4
motor
- M. iliopsoas
- M. quadriceps
Diminished
patellar reflex,
difficulties
hip flexion
Extension:
Saphenous nerve
25% bilateral!
Mechanism of lesion:
obturator nerve
• Compression between
pelvis and fœtal head
L2, L3, L4
– Lithotomy position
– Forceps
Obturator nerve
Innervation
sensory
motor
- M. adductor
L2, L3, L4
Weakness of
tigh adduction,
abnormal gait
Mechanism of lesion:
Lumbosacral plexus
L5-S4
• Compression
between pelvis and
fœtal head
– Macrosomia
– Forceps /vacuum
• Sciatic nerve: rare
• Peroneal nerve:
– External compression
at the knee
Lumbosacral plexus
Innervation
sensory
motor
- M. quadriceps
- M. adducteur
L5-S4
Deficit
highly
variable!
Foot drop,
difficulties of
hip flexion and
hip adduction
Saphenous n.
Sural n.
Potentially also
anal sphincter
dysfunction
And what about radiculopathy?
Brull, R., McCartney, C. J. L., Chan, V. W. S. & El-Beheiry, H. Neurological
complications after regional anesthesia: contemporary estimates of risk.
Anesth. Analg. 104, 965–974 (2007).
And what about radiculopathy?
N = 6048
Wong, C. A. et al. Incidence of postpartum lumbosacral
spine and lower extremity nerve injuries. Obstet Gynecol
101, 279–288 (2003).
And what about radiculopathy?
• Associated with anesthesia in retrospective
studies:
– In 17 of 24 cases of radiculopathy, there was
paresthesia during puncture of pain during
injection (Auroy 1997)
– All radicular deficits recovered except for one
deficit which ocurred after spinal anesthesia
without any paresthesia or pain
Auroy, Y. et al. Serious complications related to
regional anesthesia: results of a prospective
survey in France. Anesthesiology 87, 479–486
(1997).
OUTCOME / PROGNOSIS
Recovery depends on severity of nerve injury
Severity of injury
Neurapraxia
Axonotmesis
Predicted recovery
• Remyelination: 2-12 weeks
• Collateral sprouting and axonal
regeneration:
2-6 months
Neurotmesis
• No recovery or partial axonal
regeneration: 2-18 months
Duration
of postpartum neurological symptoms
Wong, C. A. et al. Obstet Gynecol 101, 279–288 (2003).
WORK-UP: HOW TO FIND OUT
WHO IS TO BLAME
Step 1: rule out serious problems
• Progression of
symptoms?
• Fever?
• Back pain?
• Cauda/conus symptoms?
• Neck stiffness?
Kernig sign? (pain on knee
extension with flexed hip)
• Laboratory signs of
infection?
• Epidural hematoma
• Epidural abscess
• Meningitis
Step 2: history & physical exam
• Mode of delivery?
• Duration of second
stage of labour?
• Positioning during
pushing
• Preexisting neurological
problems?
• Intact sensation on the
lower back (innervated
by posterior rami) rules
against central lesion
• Central lesions are more
often accompanied by
back pain
Step 3: central vs peripheral lesion
Central lesion
•
Affection of multiple
nerve roots without
back pain or other
signs of serious
problems is almost
never a central
problem
Peripheral nerve lesion
•
Sensory (and
motor deficit)
corresponds to
peripheral nerve
•
Tinel’s sign
positive (pain or
paresthesia when
tapping on the
injured part of
the nerve) in
peripheral lesion
Step 3: central vs peripheral lesion
Central lesion
Peripheral nerve lesion
Wong, C. A. Nerve injuries after neuraxial anaesthesia and their
medicolegal implications. Best Pract Res Clin Obstet Gynaecol 24, 367–381
(2010).
Step 4: further studies
A) imaging: MRI
– Indicated if epidural hematoma/abscess is
suspected
– May be indicated if signs of central lesion are
present, such as Lhermitte’s sign (neck flexion causing
shooting pain in the back, sign of irritation of the posterior column of
the spinal cord)
Step 4: further studies
B) Electrodiagnostic studies:
to determine prognosis of a peripheral nerve injury,
they should be performed with a delay of 10-21 days
(earlier only to rule out preexisting deficits)
Wallerian degeneration
takes 1-2 weeks to
develop,
then it shows typical signs
of denervation in the
ENMG
Step 4: further studies
B) Electrodiagnostic studies:
- indicated to determine prognosis related to
axonal loss (=extent of denervation signs)
- cannot differentiate between radiculopathy
and plexopathy
(L2, L3 and L4 roots have extensive myotomal overlap,
paraspinal muscles can be normal in radiculopathy and
abnormal in plexopathy)
Conclusion
• In most cases, history &physical examination
are clearly indicative of a peripheral nerve
lesion
• In some cases, electrodiagnostic studies and
MRI help to identify the peripheral lesion
• In rare cases, the differentiation of plexopathy
vs radiculopathy is not possible
Thank you for your attention!
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