Sacral agenesis

Caudal regression syndrome is a rare anomaly, a continuum of congenital malformations ranging from isolated sacral agenesis to absence of the lumbosacral spine and major visceral anomalies. While the exact canse of this syndrome is unclear, maternal diabetes, genetic factors, teratogens, and vascular anomalies that alter blood flow have been hypothesized to play a role. A case has been attributed to maternal minoxidil exposure (15). 

Fig. 8.1. Sacral agenesis-only SI and parts of S2 are present - indicating a high probability of an associated urologic problem...

Fig. 8.4. IVU. Sacral agenesis in a patient with hyperreflexive neurogenic bladder and imperforate anus. Vesicoureteral reflux grade 2...

Pang D (1993) Sacral agenesis and caudal spinal cord malformations. Neurosurgery 32 755-758... 

Equally important is the physical examination, which includes a careful inspection of the lower spine to look for a cutaneous manifestation of an occult spinal dysraphism and/or sacral agenesis and an examination of the external genitalia. 

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