Diagnostic accuracy of MRI for detecting nerve injury in brachial plexus birth injury

Objectives: To determine the diagnostic accuracy of MRI for diagnosing nerve injury in brachial plexus birth injury (BPBI).

Methods: Electronic databases were searched from inception to February 15, 2023 for studies reporting the accuracy of MRI (index test) compared to surgical exploration (reference standard) in detecting the target conditions of: root avulsion, any nerve abnormality, and pseudomeningocele (as a marker of root avulsion) in children with BPBI. Meta-analysis using a bivariate model was performed where data allowed.

Results: Eight studies met the inclusion criteria. In total, 116 children with BPBI were included. All included studies were at risk of bias. The mean sensitivity and mean specificity of MRI for detecting root avulsion was 68% (95% CI: 55%, 79%) and 89% (95% CI: 78%, 95%), respectively. Pseudomeningocele was not a reliable marker of avulsion. Data were too sparse to determine the diagnostic accuracy of MRI for any nerve abnormality.

Conclusions: At present, surgical exploration should remain as the diagnostic modality of choice for BPBI due to the modest diagnostic accuracy of MRI in detecting root avulsion. The diagnostic accuracy of MRI needs to be close to 100% as the results may determine whether a child undergoes invasive surgery.

Advances in knowledge: Previous research regarding MRI in detecting BPBI is highly variable and prior to our study the overall diagnostic accuracy was unclear. Through conducting a systematic review and meta-analysis, we were able to reliably determine the overall sensitivity and specificity of MRI for detecting root avulsion.