Accuracy of ultrasound and MRI in the diagnosis of common peroneal nerve injuries

BackgroundThis study aimed to determine the accuracy of ultrasound (US) and MRI compared to intraoperative findings in patients who underwent surgery for their common peroneal nerve (CPN) injury.MethodsPatients who underwent surgical management of a CPN injury with preoperative US were reviewed. The status of the CPN as interpreted by the radiologist in the preoperative US and MRI were recorded. The intraoperative findings of the CPN were compared to the imaging findings. The CPN was classified as intact, partial injury, or complete transection. The location of the injury, and presence of a neuroma-in-continuity or stump neuroma were recorded. The sensitivity and specificity of US for diagnosis of a complete transection and an intact CPN were calculated.ResultsThirteen patients were included in this study. Preoperative US accurately diagnosed a complete transection in 3 out of 4 patients and an intact CPN in 4 out of 5 patients. MRI did not accurately identify the status of the CPN in any patients. US had 75% sensitivity and 78% specificity for detecting complete transection, and 80% sensitivity and 63% specificity for detecting an intact CPN. The level of injury was correctly identified in 7 out of 13 cases by US and 1 out of 8 cases by MRI. A neuroma was correctly identified in 7 of 11 cases by US and 1 out of 8 cases by MRI.ConclusionUS has a high sensitivity and specificity when diagnosing CPN lesions and was more accurate than MRI.