[Evaluation of CT myelography and conventional myelography for avulsion injury of nerve root--18 cases of birth palsy].

CT myelography (CTM) and conventional myelography were reviewed in 18 cases of birth palsy with clinically suspected avulsion injury. A traumatic meningocele was detected in 45 roots by CTM, and in 35 roots by myelography. CTM misinterpreted only one root with a very small meningocele. CTM was superior to myelography in delineating a traumatic meningocele, because CTM is sensitive to a poorly enhanced meningocele. On the other hand, CTM missed 9 avulsed roots without a meningocele. By myelography, these 9 roots were diagnosed as 6 roots of complete avulsion injury and 3 roots of incomplete avulsion. Myelography is indispensable in evaluating nerve root avulsion.