Beyond the Chest X-Ray: Comparative Performance of Preoperative Tests for Phrenic Nerve Dysfunction in Brachial...

Area of Science:

• Neurosurgery
• Diagnostic Imaging
• Respiratory Medicine

Background:

• Phrenic nerve injury is common in brachial plexus injuries (BPI), impacting respiration.
• Preoperative assessment of phrenic nerve function is crucial for managing respiratory compromise and planning nerve reconstruction.
• Current diagnostic methods like chest X-rays (CXR) have limited sensitivity for detecting phrenic nerve dysfunction.

Purpose of the Study:

• To systematically compare the diagnostic performance of various preoperative imaging modalities for phrenic nerve assessment in BPI.
• To identify the most accurate method for evaluating phrenic nerve function against intraoperative stimulation as the gold standard.

Main Methods:

• Retrospective review of 113 patients undergoing brachial plexus reconstruction (2020-2024).
• Comparison of chest sonography, chest radiography (CXR), pulmonary function testing (PFT), and magnetic resonance neurography (MRN) against intraoperative phrenic nerve stimulation.
• Calculation of sensitivity, specificity, accuracy, and AUC for each modality.

Main Results:

• Chest sonography demonstrated the highest diagnostic accuracy (100% sensitivity, 80% specificity, AUC 0.900).
• CXR had high specificity (93%) but low sensitivity (44%, AUC 0.687).
• PFT showed moderate sensitivity (86%) and low specificity (58%, AUC 0.718), while MRN performed poorly for both C4 and C5 root injuries.

Conclusions:

• Chest sonography is the most reliable preoperative tool for assessing phrenic nerve function in BPI patients.
• CXR's low sensitivity restricts its use as a standalone diagnostic test.
• A combined approach using sonography and CXR may improve diagnostic accuracy for phrenic nerve assessment.