Perioperative management of patients with spina bifida

Question 1

What is Spina Bifida

Answer 1

• Congenital neural tube defect resulting from incomplete spinal column closure during embryonic development

Question 2

Incidence of Spina Bifida

Answer 2

6 in 10,000 (declined following folic acid supplementation)

Question 3

Spina Bifida Occulta

Answer 3

Failure of fusion of the posterior vertebral body but the spinal cord is covered by skin or s/c fat. Can have a tethered spinal cord

Question 4

Spina Bifida Aperta

Answer 4

Exposed spinal cord, can be meningocele (spinal cord not in exposed sac) or myelomeningocele (spinal cord in exposed sac)

Question 5

RFx for development of Spina bifida

Answer 5

• Trisomy 13 and 18
• Folate deficiency
• Maternal diabetes
• Antiepileptic medications
• Hyperthermia
• Obesity

Question 6

CFx of Spina Bifida

Answer 6

• Hydrocephalus secondary to Chiari 2 malformation- vomiting, irritability, increasing head circumference, coma
• Motor deficit dependent on level of lesion
• Sensory deficit dependent on level of lesion
• Central apnoeas, stridor and swallowing difficulties- Chiari 2
• Urinary incontinence or retention
• Constipation
• Spasticity and hip and foot deformities
• Scoliosis- restrictive lung disease
• Pressure ulcers
• Central OSA -> pulm HTN

Question 7

Pre-Op Assessment of Spina Bifida

Answer 7

• Assess sensory and motor deficits
• VP shunt in situ?
• Seizures and compliance with anti-epileptics
• Airway assessment- kyphoscoliosis common, macrocephaly
• Resp- Restrictive lung disease, central apnoea
• CV- Rt heart function
• Renal- if bladder dysfunction check U&Es

Question 8

Intra-op Management of Spina Bifida

Answer 8

• Latex-free environment (high risk of sensitisation
• Art line if CV involvement
• Difficult IV access
• Positioning
• Pressure sores
• Risk of endobronchial intubation as short tracheas
• Risk of aspiration- bulbar palsy
• Difficult ventilation- restrictive lung disease
• High-risk neuraxial blockade- low-lying conus, cysts etc.

Question 9

Post-Op Considerations in Spina Bifida

Answer 9

• May have reduced analgesia requirements depending on the level of lesion
• NSAIDs may be contraindicated if renal dysfunction
• Careful opioid use if central apnoeas
• Prolonged O2 use and CPAP

Question 10

Common surgical procedures for spina bifida

Answer 10

Closure of myelomeningocele
- prone
- risk of high ICP

Post fossa decompressive craniectomy
- Prone
- Avoid neck manipulation because you might be pressing on the brainstem
- High risk of blood loss
- Brainstem traction - asystole

Tethered cord release
- Spinal ischaemia MAP targets
- SSEP and MEPS monitored

Spinal surgery
- Generally scoliosis correction