Sonographic evaluation and conservative management of newborns with myelomeningocele and hydronephrosis.

Hydronephrosis has been reported in 7 to 60 per cent of all newborns with myelomeningocele. However, most of these reports have been based upon x-ray findings obtained after closure of the myelomeningocele. To determine whether the radiographic abnormalities might be secondary to the neurosurgical procedure in a manner analogous to spinal shock, a prospective study of 34 newborns with myelomeningoceles was done during a 5-year period. Renal and bladder sonography was done on day 1 of life before surgical intervention and for varying periods thereafter. A total of 31 infants (91 per cent) had normal renal sonograms preoperatively but 6 of these had bilateral hydronephrosis and distended bladders postoperatively. Three patients had urinary retention before postoperative sonography could be obtained. For these 9 patients intermittent catheterization was required for 4 to 14 days until bladder tone recovered. Urinary retention in the infant with myelomeningocele may be a transient consequence of the myelomeningocele repair and should be treated conservatively for at least 2 weeks before surgical intervention is considered seriously.