Diagnostic Accuracy of Magnetic Resonance Imaging for Nerve Injury in Obstetric Brachial Plexus Injury: Protocol for Systematic Review and Meta-analysis

Abstract BackgroundObstetric brachial plexus injury (OBPI) is typically caused by excessive traction to the neck during delivery and can cause permanent dysfunction of the upper limb. Surgical exploration is typically performed at 3 months of age if insufficient signs of spontaneous functional recovery are demonstrated, and nerve reconstruction is performed at this point if indicated. Magnetic resonance imaging (MRI) offers a non-invasive alternative in detecting nerve injury, however the reported diagnostic accuracy in existing literature is conflicting. A systematic review is therefore required to clarify the accuracy of MRI and help define its role clinically. The primary objective is to determine the diagnostic accuracy of MRI for detecting root avulsion in obstetric brachial plexus injuries. The secondary objectives are to determine the diagnostic accuracy of MRI for detecting any nerve abnormality (including post-ganglionic injury) and to determine the diagnostic accuracy of MRI for detecting pseudomeningocele(s) as a surrogate marker of root avulsion.MethodsElectronic databases will be searched systematically for studies reporting the accuracy of MRI (index test) compared to surgical exploration (reference standard) in detecting root avulsions, other nerve abnormalities and pseudomeningocele in children with OBPI. A revised QUADAS-2 tool will be used to assess methodological quality of included studies. If appropriate, summary sensitivities and specificities for target conditions (root avulsion, abnormal nerve and pseudomeningocele) will be obtained via meta-analyses using a bivariate model. DiscussionThis study will aim to clarify the current diagnostic accuracy of MRI for detecting nerve injury and define its clinical role. Systematic review registrationPROSPERO registration CRD42021267629.