Longitudinal evaluation of motor function in patients who underwent prenatal or postnatal neural tube defect repair

Abstract

Objective To compare the evolution of motor function from mid‐gestation to 12 months of age between prenatally and postnatally repaired cases of open neural tube defect (ONTD). Methods This was a retrospective cohort study of all fetuses that underwent prenatal (fetoscopic or open hysterotomy) or postnatal ONTD repair at a single institution between November 2011 and December 2018. The anatomical level of the lesion was defined as the upper bony spinal defect at initial magnetic resonance imaging assessment. Prenatal motor function of the lower extremities was evaluated by ultrasound according to the metameric level of the neurological lesion, based on the methodology of Carreras et al. Fetal motor function was assessed at referral, at 6 weeks after surgery in prenatally repaired cases or 6 weeks after referral in postnatally repaired cases (6‐week follow‐up) and at the last scan before delivery. In addition, motor function was assessed by a detailed neurological examination at birth and 12 months of age. First sacral (S1) neurological level of the lesion was considered as intact motor function. For statistical comparisons, we attributed numerical scores to each neurological level and motor function was expressed as median (range) neurological level. Motor function (as numerical score) and the proportion of cases with intact motor function and with motor function two or more levels better than expected based on the anatomical level of the lesion were compared between the prenatal‐ and postnatal‐repair groups. Fetal motor function was compared to the anatomical level of the lesion at referral and a better motor function was defined when it was two or more levels better than the anatomical level of the lesion. To assess the evolution of motor function, we compared motor function at referral with that at each follow‐up assessment using paired t‐tests. Results We included 127 patients with ONTD, of whom 93 underwent prenatal (51 fetoscopic and 42 open hysterotomy) and 34 postnatal repair. At the time of referral, cases in the prenatal‐ and postnatal‐repair groups presented with a similar anatomical level of lesion (L3 (T9–S1) vs L3 (T7–S1); P = 0.52), similar motor function (S1 (L1–S1) vs S1 (L1–S1); P = 0.52) and a similar proportion of cases with intact motor function (81% vs 79%; P = 0.88) and with motor function two or more levels better than expected based on the anatomical level of the lesion (62% vs 74%; P = 0.24). When compared with prenatally repaired cases, postnatally repaired cases showed worse motor function at birth (S1 (L1–S1) vs L4 (L1–S1); P < 0.01) and at 12 months of age (S1 (L1–S1) vs L4 (L1–S1); P < 0.01). In the prenatal‐repair group, motor function remained stable from the time of referral to 12 months of age (P = 0.26). Furthermore, the proportion of patients with intact motor function at referral (81% (75/93)) was similar to that at the 6‐week follow‐up (74% (64/87)), at the last scan before birth (74% (42/57)), at birth (68% (63/93)) and at 12 months of age (67% (39/58)) in the pren...

Comparison of two fetoscopic open neural tube defect repair techniques: single‐ vs three‐layer closure

“…Prior to surgery, all patients underwent comprehensive maternal health evaluation, fetal magnetic resonance imaging (MRI), fetal ultrasound examination and fetal echocardiography, a mental health evaluation, social circumstances assessment and a full multidisciplinary team consultation. A detailed description of the prenatal and postnatal imaging examinations and assessments performed, as well as management, is published elsewhere 7 .…”

Update on prenatal diagnosis and fetal surgery for myelomeningocele

“…It has been demonstrated that intrauterine damage of the nervous system is progressive. 44 The "two-hit hypothesis" suggests that an initial lesion occurs, the anatomical defect itself, and then a second lesion due to the ongoing exposure of the nervous tissue to amniotic fluid. [45][46][47] Therefore, based on the hypothesis that an early defect closure may be associated with improved postnatal outcomes by reducing exposure of the neural tissue to amniotic fluid for a prolonged time, the concept of prenatal repair was introduced.…”

“…[45][46][47] Therefore, based on the hypothesis that an early defect closure may be associated with improved postnatal outcomes by reducing exposure of the neural tissue to amniotic fluid for a prolonged time, the concept of prenatal repair was introduced. 3,44,46 In 2011, the MOMS trial was published, which compared the outcomes of open prenatal surgery and postnatal surgery. 3 The study was ended early due to the clear benefits observed in the prenatal surgery group, which showed, at the 12-month follow-up, a reduction in VPS requirement (40 % in the prenatal versus 82 % in the postnatal surgery group; relative risk [RR] = 0.48; 97.7 % confidence interval [CI]: 0.36-0.64; p < 0.001) and, at the 30-month followup, an improved composite outcome of mental development and motor function.…”

Actualización del diagnóstico prenatal y cirugía fetal del mielomeningocele

“…Se ha demostrado que el daño intraútero del sistema nervioso es progresivo. 44 La "teoría de los 2 golpes" sugiere que hay una primera lesión, el defecto anatómico en sí, y luego una segunda, dada por la continua exposición del tejido nervioso al líquido amniótico. [45][46][47] Por ello, con la hipótesis de que el cierre precoz del defecto podría asociarse a mejores resultados posnatales al disminuir la exposición del tejido neural al líquido amniótico durante un período prolongado, se introdujo el concepto de la corrección prenatal.…”

“…[45][46][47] Por ello, con la hipótesis de que el cierre precoz del defecto podría asociarse a mejores resultados posnatales al disminuir la exposición del tejido neural al líquido amniótico durante un período prolongado, se introdujo el concepto de la corrección prenatal. 3,44,46 E n e l a ñ o 2 0 1 1 , s e p u b l i c ó e l M O M S , el cual comparó los resultados de la cirugía prenatal abierta con la posnatal. 3 El estudio fue interrumpido precozmente debido a los claros beneficios en la rama de la cirugía prenatal, que mostró, en el seguimiento a 12 meses, una reducción de la necesidad de colocación de DVP (el 40 % en el grupo de cirugía prenatal vs. el 82 % en el grupo posnatal; riesgo relativo -RR-= 0,48; intervalo de confianza -IC-del 97,7 %: 0,36-0,64; p < 0,001) y, en el seguimiento a 30 meses, una mejoría en el resultado compuesto de desarrollo mental y función motora.…”