Perinatal motor function loss in human spina bifida aperta

PhD ceremony: Ms. R.J. Verbeek, 16.15 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: Perinatal motor function loss in human spina bifida aperta

Promotor(s): prof. O.F. Brouwer

Faculty: Medical Sciences

We studied the initiation and evolvement of segmental neuromuscular damage in children with myelomeningocele, the severe variant of a congenital neural tube defect or spina bifida aperta (SBA). Therefore, we measured muscle ultrasound density (MUD) in association with leg motor function loss both before and after birth. Results confirm the existence of two different impacts upon the segmental neurological leg-condition: 1. ‘congenital’ damage as a direct consequence of the MMC, and 2. delayed, perinatal damage by secondary spinal trauma. The results indicating delivery-related spinal segmental haemorrhages located near persistent lower motor neurons, might explain the early neonatal disappearance of leg movements. This secondary perinatal segmental spinal damage, superimposed upon the congenital MMC, is hypothetically referred to as the ‘second-hit’ of spinal damage. During the first year of life, the evolution of SBA leg MUD alterations reflects the impact of both ‘congenital’ and ‘second-hit’ spinal damage upon leg muscle integrity. Afterwards (1-18 years) leg-MUD parameters reflect a ‘stabilised’ neuromuscular leg condition (i.e. completion of ‘second-hit’ damage). Fetal closure of the MMC might protect aberrant blood vessels from bleeding and preserve neurological function. We found that fetal endoscopic surgery is associated with better spinal neuroprotection than neonatal surgery, but this is at the cost of iatrogenic morbidity for mother and child. Before considering clinical implementation of fetal MMC treatment as standard care, the frequency and impact of these complications should be reduced and investigated in larger study groups over a longer period of time.