Utility of electrodiagnostic testing and computed tomography myelography in the preoperative evaluation of neonatal brachial plexus palsy

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>The rate of neonatal brachial plexus palsy (NBPP) remains 0.4%–4% despite improvements in perinatal care. Among affected children, the extent of brachial plexus palsy differs greatly, as does the prognosis. Controversial elements in management include indications and timing of nerve repair as well as type of reconstruction in patients in whom function will ultimately not be recovered without surgical intervention. Differentiating preganglionic (avulsion) from postganglionic (rupture) lesions is critical because preganglionic lesions cannot spontaneously recover motor function. Distinguishing between these lesions at initial presentation based on clinical examination alone can be difficult in infants. The purpose of the present study was to determine the sensitivity of preoperative electrodiagnostic studies (EDSs) and CT myelography (CTM) in determining the presence of nerve root rupture and avulsions in infants with NBPP.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>After receiving institutional review board approval, the authors conducted a retrospective review of patients referred to the Neonatal Brachial Plexus Program between 2007 and 2010. Inclusion criteria included children who underwent brachial plexus exploration following preoperative EDSs and CTM. The CTM scans were interpreted by a staff neuroradiologist, EDSs were conducted by a single physiatrist, and intraoperative findings were recorded by the operating neurosurgeon. The findings from the preoperative EDSs and CTM were then compared with intraoperative findings. The sensitivities and 95% confidence intervals were determined to evaluate performance accuracy of each preoperative measure.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Twenty-one patients (8 male amd 13 female) met inclusion criteria for this study. The sensitivity of EDSs and CTM for detecting a postganglionic rupture was 92.8% (CI 0.841–0.969) and 58.3% (CI 0.420–0.729), respectively. The sensitivity for EDSs and CTM for preganglionic nerve root avulsion was 27.8% (CI 0.125–0.509) and 72.2% (CI 0.491–0.875), respectively. In cases in which both CTM and EDSs gave concordant results, the sensitivity for both modalities combined was 50.0% (CI 0.237–0.763) for avulsion and 80.8% (CI 0.621–0.915) for rupture. Overall, EDSs were most useful in identifying ruptures, particularly in the upper plexus, whereas CTM was most sensitive in identifying avulsions in the lower plexus.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Knowledge of the spinal nerve integrity is critical for early management of patients with NBPP. Surgical management, in the form of nerve repair/reconstruction, and optimal prognostication of NBPP depend on the accurate diagnosis of the level and type of lesion. Both EDSs and CTM scans must always be interpreted in the context of a comprehensive evaluation of the patient. They provide supplemental information (in addition to the physical examination) for early detection of nerve root rupture and avulsion injuries, aiding surgical decision making and preoperative planning for NBPP. Continued advances in imaging, EDSs, and microsurgical nerve repair techniques will allow surgeons to achieve greater success for functional recovery in management of NBPP.</jats:p></jats:sec>

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

“…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).…”

“…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.…”

“…Similar to authors of other studies, we report predictive values by using sensitivity, specificity, and predictive values [14][15][16]18,19,[35][36][37] ; and we used clinical examination and/or findings on extradural surgical exploration as our reference standard for the detection of root avulsions. [14][15][16]18,19,35,37,45 Hemilaminectomy and opening of the dura mater would provide a more accurate reference standard and have been used to assess CT, 13,27 MR imaging, 32 and both CT and MR imaging 46 findings in adults.…”

Neonatal brachial plexus palsy: a permanent challenge

“…Motor nerve conduction studies can estimate the percentage of motor axonal degeneration, which correlates with the functional outcome 26 . Preservation of sensory potentials in a patient with severe paralysis is indicative of pre ganglionar lesion, which carries a grim prognosis 27 . Biceps needle electromyography at one month of age has been used as part of Leiden´s University algorithm for surgical indication in these patients 28 .…”