Prenatal diagnosis of open and closed spina bifida.
OBJECTIVE
To identify criteria useful for differentiating closed from open spina bifida antenatally.


METHODS
A retrospective study of cases of spina bifida diagnosed in a referral center between 1997 and 2004.


RESULTS
Of 66 cases of fetal spina bifida diagnosed at a median gestational age of 21 (range, 16-34) weeks, detailed follow-up was available for 57. Of these, open defects were found in 53 (93.0%) and closed defects in four (7.0%). Closed spina bifida was associated in two cases with a posterior cystic mass with thick walls and a complex appearance, while in two cases the spinal lesion could not be clearly differentiated from an open defect, particularly at mid-gestation. Open spina bifida was always associated with typical alterations of cranial anatomy, including the so-called 'banana' and 'lemon' signs, while in closed spina bifida the cranium was unremarkable. When the data were available, levels of amniotic fluid alpha-fetoprotein were always abnormally elevated with open spina bifida and within normal limits with closed forms.


CONCLUSIONS
In this study 7% of cases of spina bifida diagnosed in utero were closed. The differentiation between open and closed forms is best shown by the sonographic demonstration of abnormal or normal cranial anatomy.
Ghi
T
T
Department of Obstetrics and Gynecology, Policlinico S. Orsola-Malpighi and University of Bologna, Bologna, Italy.
Pilu
G
G
Falco
P
P
Segata
M
M
Carletti
A
A
Cocchi
G
G
Santini
D
D
Bonasoni
P
P
Tani
G
G
Rizzo
N
N
D003937:Diagnosis, Differential; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D012189:Retrospective Studies; D016135:Spinal Dysraphism / Q000175:diagnosis* / Q000196:embryology; D016216:Ultrasonography, Prenatal / Q000379:methods*