anaesthesia management for meningomyelocoele management. Anaesthesia management has been described with specific concerns in these patients. Key management stratergies have also been discussed in detail.

1. Dr. Swati Daftary
Consultant Anaesthesiologist
Jaslok Hospital, Mumbai
Anaesthetic Management Of A
Child With Meningomyelocele
ARC 2015

2. Types Of Myelodysplasia

3. Meningomyelocele (MMC)
Type of Myelodysplasia
• Abnormal fusion of the embryological neural
groove during the third and fourth week of
gestation  herniation of meninges & neural
elements
• Incidence: 2–5/1000 live births
• Neural tube defects above the thoracolumbar
junction show a mild female preponderance
• Commonest in lumbo-sacral region

4. Encephalocele

5. Predisposing Factors
• Nutritional deficiency of Folic acid in mothers
• Associated chromosomal abnormalities –
trisomies 13 & 18, single gene mutations
• Recurrence risk for parents with one affected
child is about 5%, for monozygotic twins 20%
• Maternal Insulin-Dependent Diabetes mellitus,
hypothermia
• Intrauterine exposure to carbamazepine,
valproate, and ovulation inducing drugs

6. MMC: Intrauterine Diagnosis
Imaging studies:
• Fetal ultrasound at 18 weeks gestational age
Lab. studies:
• Elevated maternal serum  fetoprotein levels in
second trimester – nonspecific
• Amniotic fluid  fetoprotein assay
• Presence of acetyl cholinesterase (a nerve specific
enzyme) in amniotic fluid

7. MMC: Associated Anomalies
• Arnold-Chiari type II malformation (80-90%)
• Hydrocephalus (15-25% at birth  80% shunt sx)
• Neurogenic bladder (90%)
• VACTERL associations
• Musculo-skeletal defects (spine, joints, bones,
umbilical hernia)
• Urogenital anomalies- Extrophy bladder,
undescended testis, hydronephrosis, solitary
kidney, malformed ureters
• Facial clefts

8. CSF Pathway
Sup. Sagittal sinus
Subarachnoid
space
Aqueduct of
Sylvius
Foramen of
Monroe
Foramen of Magendie
& Luschka
III
IV

9. • Caudal herniation of
the vermis, brainstem,
and fourth ventricle
• Associated with
meningomyelocele and
multiple brain
anomalies
• High frequency of
hydrocephalus and
syringohydromyelia
Arnold-Chiari Malformation Type II

10. Hydrocephalus In MMC
Obstructive in nature because of associated
• Arnold-Chiari II malformation
• Presence of a degree of aqueductal stenosis
• Anomalous venous drainage in the posterior fossa
caused by compression of the sigmoid sinuses
• Presence of other CNS malformations
• Ventricular shunt placed once MMC is repaired

11. MMC
Hydrocephalus: Axial MRI
Partial or complete absence of the falx and absence of the septum pellucidum
 small frontal and large occipital horns of ventricles in MMC
MMC

12. MMC Repair: A Surgical Emergency
• Should be carried out in first 48 hours of life
• Delay in closure of MMC ↑es incidence of
• Infection
• Dehydration
• Progressive neural damage and decreased
motor function
• Latex-free precautions from birth are more
effective in preventing latex sensitization

13. MMC: Surgical Management
• Intrauterine repair of MMC
• Planned c-section before rupture of the amniotic
membranes and onset of labor
• After delivery, immediate surgery for closure of
MMC if impending rupture/leak or open MMC
• In children with open MMC, simultaneous shunting
and closure of MMC protects from acute onset
hydrocephalus and CSF leak from the spinal wound
• If CSF is infected  external ventricular drainage &
antibiotic cover for 7-10 days, followed by shunt Sx

14. Anaesthetic Implications
• Susceptible to latex allergy (30-70%)
• Large third space losses from the exposed MMC
• Positioning for induction & surgery
• Large intraoperative losses
• CSF loss
• Blood loss due to dissection of skin flaps
• Heat loss  hypothermia
• Problems of prematurity
• Associated with Arnold-Chiari II malformation 
• Impaired swallowing & gag reflexes → aspiration, stridor
• ↓/ absent response to hypoxia & hypercarbia → apnoea

15. Anaesthetic Considerations
General:
• Concerns of anaesthesia for newborns
• Concerns of anaesthesia for premature infants
• Retinopathy of prematurity
• Hypothermia
• Careful ventilation: prevent pulmonary trauma
• Care of postoperative apnoea & periodic
breathing

16. Anaesthetic Considerations
Specific:
• Adequate preoperative hydration
• Antibiotics to be continued
• Protect neuroplaque
• A secure airway in prone position
• Careful padding of pressure points
• Prevent hypothermia with fluid warmers, warm &
humidified anaesthetic gases & forced air warmer
• Adequate blood availability if lesion is extensive

17. Anaesthetic Considerations
Measures to prevent ↑ in trans-tentorial pressure
gradient to prevent coning:
•Appropriate anaesthetic agents & technique
• Atropine premedication & preoxygenation
• IV induction with thiopental or propofol followed by a
muscle relaxant for ET intubation
• Controlled hyperventilation with O2+N2O in isoflurane /
sevoflurane & short acting opioid
• No further muscle relaxant if nerve root monitoring
required
•Avoid sudden release of pressure from the sac
•Head low position

18. Positioning For Induction
• Positioning the patient for tracheal intubation
may rupture the membranes covering the spinal
cord
• Careful padding of the lesion or placing the child
on a foam with circular cut-out to protect the
lesion
• In some cases intubation of the neonate in the
lateral position

19. Positioning In Meningomyelocele

20. Physiologic Effects Of Positioning
• Prone:
• Venous congestion of face, tongue, and neck
• Decreased lung compliance
• Increased abdominal pressure  venocaval
compression
• Head-down:
• Increased cerebral venous pressure and ICP
• Decreased functional residual capacity
• Decreased lung compliance

21. Positioning For Surgery
• Padding under the chest and pelvis / soft rolls to
elevate & support the lateral chest wall, hips to
ensure free abdominal wall motion when prone
• Extreme rotation of the head can impede venous
return through the jugular veins & lead to impaired
cerebral perfusion, worsening ↑ed ICP
• Extreme head flexion can cause brainstem
compression in Arnold-Chiari malformation type II
• Eyes: Avoid direct contact with the head rest to
prevent postoperative visual loss

22. Prone Position: Care Of Eyes
Prone – Head Rest (Mirror)
Prone Positioner

23. Intraoperative Monitoring
• Clinical- colour, pulse, ventilation, blood loss
• Precordial / oesophageal stethoscope
• Pulse oximeter
• ECG
• NIBP monitor
• Capnometer
• Airway pressures
• Temperature monitor
• Peripheral nerve stimulator, nerve root monitoring

24. Perioperative Problems
• Airway management: encephalocele, hydrocephalus
• Muscle relaxation
• Water tight closure of dura
• Postoperative acute hydrocephalus
• Postoperative respiratory distress can happen after
repair of large thoracic MMC
• Postoperative nursing- position, respiration,
oxygenation, temperature maintenance
• Patient may require postop ventilatory support
• Postoperative persistent CSF leak from the repaired
spinal wound indicates active hydrocephalus

25. How Does Fetal Surgery Help In
Meningomyelocele?
 Spinal cord exposed to the caustic effects of
amniotic fluid and mechanical compression
 Progressive & irreversible damage
 Absent lower extremity function (>20 weeks) &
ed incidence of hindbrain herniation
 Shunt dependent hydrocephalus
Treatment: Intrauterine excision and microsurgical
layered repair

26. MOMS- Management of meningomyelocele study NIH
(February 2003 to December 2010, 183 patients)
Results: Prenatal surgery was associated with
•Reduced shunt dependency by half (40% vs. 82%)
•Double no. of patients walked on their own at age 3
(42% vs. 21%)
•↑ risk of preterm delivery and uterine dehiscence

27. Prenatal Repair Of MMC
First repair was done in 1997

28. Surgeries Post MMC Repair
• Shunt surgery for hydrocephalus: patients may be
on acetazolamide &/or lasix
• Bladder augmentation for neurogenic bladder:
patients may be on anticholinergics / tricyclic
antidepressants /  adrenergic antagonists,
untreated patients may have CRF
• Detethering of spinal cord
• Surgery for coexisting spine, bone, joint
deformities, other congenital anomalies
• High incidence of latex allergy

29. Latex Anaphylactic Reaction
IgE mediated allergic reaction in latex-sensitised
patients (H/O multiple surgical procedures, atopy,
occupational exposure) on exposure to latex
Prevention: Provide a latex-free environment
• Patient should be scheduled as the first case
• Latex allergy cart with latex free supplies
• Anaesthesia machine & monitors with rubber free
circuits and accessories
• Don’t draw up drugs from vials with rubber
stoppers
• Avoid syringes with rubber plungers, do not use
injection ports of IV infusion set for injections

30. Treatment Of Latex Anaphylaxis
Primary treatment:
• Stop administration of latex
• Maintain airway with 100% oxygen
• Discontinue all anaesthetic agents
• Restore intravascular volume, start two large bore
IV lines, 25-50 ml/kg of crystalloid or colloid
• The pharmacological cornerstone of treatment is
EPINEPHRINE- Start with a dose of 10 g or 0.1
g/kg IV, subcutaneously larger dose (300 g)

31. Treatment Of Latex Anaphylaxis
Secondary treatment:
• Corticosteroids (0.25 - 1 g hydrocortisone or 1 - 2
g methylprednisolone)
• H1 and H2 antagonists
• Epinephrine infusion
• Aminophylline (5 - 6 mg/kg over 20 minutes for
persistent bronchospasm)
• Sodium bicarbonate (0.5 - 1 mEq/kg for persistent
hypotension with acidosis)
• Airway evaluation (prior to extubation)

32. Shunt Surgery For Hydrocephalus
Anaesthetic Implications:
• Level of consciousness
• Starvation / full stomach
• Brain stem involvement
• Bradycardia due to raised ICP
• Hypothermia
• Ventricular cannulation  ↓ in BP
• Burrowing the subcutaneous tunnel  Pain
• Revision / removal of ventricular end  fatal
haemorrhage (choroid plexus rupture)
• Air embolism

33. Neurogenic Bladder In MMC
Neurogenic bladder sphincter dysfunction (NBSD):
MMC  disordered innervation of the detrusor
musculature, external sphincter   intravesical
pressure  VUR, obstructive hydronephrosis 
urinary tract infections, ultimately renal failure
Medical management: CIC and anticholinergics
Surgical management: Botox injections, bladder
augmentation with enterocystoplasty or continent
urinary diversion (appendicovesicostomy)

34. Surgery For Tethered Spinal Cord
• Nerve Root Monitoring to prevent inadvertent
injury to functional nerve roots
• EMG electrodes in the anal and urethral (in
females) sphincter for continuous monitoring of
pudendal nerve (S2 to S4)
• Monitoring of Anterior tibialis & Sural muscles
• Muscle relaxation must be discontinued before
stimulation to accurately detect motor activity
• Deep plane of anaesthesia required as direct nerve
root stimulation elicits significant sympathetic
response and pain