Lumbosacral Agenesis: Clinical Characteristics, Imaging, and Embryogenesis

Abstract

We report 5 cases of complete, or nearly complete, agenesis of the lumbar and sacral spine. In 1 case pregnancy was terminated at 23 weeks of gestation, and the others were livebirths. The surviving 4 patients were all infants of diabetic mothers. Imperforate anus was present in 2 of 4 liveborn patients and was suspected in the abortus. All liveborn cases were paraplegic, and all exhibited the ‘Buddha’ deformity of the lower extremities. One patient had congenital obstructive hydrocephalus, probably representing a variant of holoprosencephaly, requiring a ventriculoperitoneal shunt. No other nervous system anomaly was identified in any patient, and the other patients are showing normal cognitive development. We propose that these patients have defects which occurred during germ cell formation (i.e., during gastrulation), with interruption of the primitive streak resulting in combined failure of primary and secondary neu-rulation.

Spectrum ofHLXB9gene mutations in Currarino syndrome and genotype-phenotype correlation

“…Partial or total sacral agenesis of the sacrum (SA) is a spinal dysraphism following a complex malformative process occurring during the first stages of embryologic development at the caudal end [Pang, 1993]. Consequently, SA is rarely isolated and often associated with other congenital defects of hindgut, urogenital system and/or spinal cord, as observed in the OEIS complex (omphalocele, cloacal exstrophy, imperforate anus, and spinal deformities), cloacal or bladder exstrophies, VACTERL syndrome (vertebral, anorectal, cardiac, tracheo-oesophageal, renal, and limb anomalies), or sirenomelia in extreme cases [Harlow et al, 1995]. Hereditary forms of SA have only been observed in CS.…”

Sonographic Evaluation of Fetal Conus Medullaris and Filum Terminale

“…Assessment of the conus must be associated with careful examination of the sacrum for appropriate screening because both entities share a common embryological origin [9]. Sonographic evaluation of the fetal sacrum is still poorly described in the literature.…”

Congenital Thoracic Cord Segmental Amyelia: A Rare Manifestation of Segmental Spinal Dysgenesis

“…SSD is a rare congenital spinal anomaly characterized by localized agenesis or dysgenesis of the lumbar, thoracolumbar or rarely the lumbosacral spine, severe kyphosis or kyphoscoliosis and focal abnormalities of the underlying spinal cord and nerve roots [1, 2, 4, 5, 6]. The malformation is typically segmental.…”

“…Associated deformities of the lower limbs are common and are mainly represented by flexion-abduction of the hip joints, flexion of the knees and equinovarus feet, which in the most severe forms result in a sitting position described as ‘Buddha-like’. Even though patients with SSD are not necessarily paraplegic at presentation, they are at increased risk for development of neurologic deficits owing to the instability and congenital stenosis of the spine, aggravated by the frequent presence of closed spinal dysraphism [1, 2, 5, 6]. …”