Obstetric Brachial Plexus Lesions: CT Myelography

Abstract

Purpose:To evaluate the value of computed tomographic (CT) myelography in the detection of root damage and differentiation of root avulsions from neurotmesis in a large cohort of patients with an obstetric brachial plexus lesion (OBPL). Materials and Methods:Institutional review board approval was obtained. Informed consent was waived by the medical ethics committee. One hundred eighteen patients with OBPL born in the cephalic position and six patients born in the breech position were selected for surgery by two neurosurgeons in a multidisciplinary team. Functional loss of the C5 through T1 innervated muscles was noted. All patients underwent preoperative CT myelography at an average age of 19 weeks. CT myelographic examination results were reviewed by two radiologists, who were blinded to the clinical fi ndings, for the presence of root avulsions and pseudocysts. Interobserver agreement was assessed by calculating k values. Results:CT myelographic results showed root avulsions in at least one level in 66 (56%) of 118 patients born in the cephalic position and in six (100%) of six patients born in the breech position. Levels C7 and C8 showed the most root avulsions, even if not expected from clinical examination results. A large number of root avulsions showed pseudocysts (73 [68%] of 107 levels in patients born in the cephalic position and 11 [73%] of 15 levels in patients born in the breech position). Conclusion:CT myelographic results showed root avulsions in more than half of patients with OBPL. Root avulsions were even detected at levels that were not expected at clinical examination. Because root avulsions require specifi c reconstructive techniques, CT myelography is recommended for every preoperative patient with OBPL.

The Diagnostic Value of CT Myelography, MR Myelography, and Both in Neonatal Brachial Plexus Palsy

“…In contrast to other studies, which excluded imaging studies based on poor quality or technical error, 12,14 we included all imaging studies to allow us to compare the 2 modalities in a practical clinical setting.…”

“…Although CT myelography is the established standard in adults 13,18,19,26-28 and infants, 12,14,15,29 the risk of infection and seizure related to intrathecal contrast administration [20][21][22] and evidence that early exposure to radiation may increase later risks of malignancy 23,24 make identifying an alternative important.…”

“…The findings and predictive values of CT myelography compared with MR myelography were almost the same and were consistent with those previously reported in the literature. 12,[14][15][16]18,19 Other nerve root findings in the absence of pseudomeningocele were also analyzed (absent rootlets, thinned rootlets, and thickened rootlets). These findings did not improve the predictive values for CT, MR imaging, or both CT and MR myelography (Table 4).…”

“…[8][9][10][11] Nerve injuries distal to the intervertebral foramen can be reconstructed by using nerve grafts, whereas intraforaminal nerve root avulsions require nerve transfer. While both partial and complete nerve root avulsions are described, 12,13 there is no clear consensus on the surgical approach to partial nerve root avulsions. Preoperative imaging capable of accurately identifying complete nerve root avulsions and distinguishing them from extraforaminal nerve injuries is, therefore, critical for optimal surgical planning.…”

“…12,[14][15][16][17][18][19] A pseudomeningocele is suggestive of nerve root avulsion, and the additional finding of absent rootlets traversing the pseudomeningocele greatly increases the specificity of this finding. 14 CT myelography requires a lumbar puncture for injection of intrathecal contrast, with attendant risks of infection and seizure.…”