Magnetic Resonance Imaging of Brachial Plexopathy after Prolonged Prone Positioning

Prone positioning improves hypoxemia and survival in patients with severe acute respiratory distress syndrome (ARDS). At our institution, patients with COVID-19 and severe ARDS were placed in prone position for 12 to 16 h daily in accordance with management guidelines. Prolonged mechanical ventilation and prone positioning may increase the risk of peripheral nerve injuries.1 Figure 1 highlights a novel and intrinsic, enhancing abnormality in a T2-weighted coronal plane magnetic resonance image of the right brachial plexus from a 61-yr-old man with body mass index 25.8 who had COVID-19–related ARDS requiring mechanical ventilation and 5 days of prone positioning at 16-h intervals. Although no discrepancies in padding or arm position were noted, examination performed during sedation wean noted sensation loss throughout the right upper extremity; flaccid paralysis of the shoulder, elbow, and wrist; and hyporeflexia. Upon extubation, the patient endorsed severe burning pain in the C6 through C8 dermatomes. The enclosed image suggests brachial plexopathy, which was later confirmed by electromyography, an alternative diagnostic modality.Fig. 1.: Coronal magnetic resonance imaging section of the brachial plexus. The arrow points to thickening and enhancement of the divisions of the right brachial plexus compared to the left brachial plexus. On this 1.5-Tesla magnetic resonance image, there is increased T2 signal on T2 fat saturated sequence with postcontrast enhancement.Prone positioning predisposes patients to a higher risk of neuropathic injury from stretching or neural compression. Some studies have noted the incidence of neuropathic injury secondary to intraoperative positioning to be approximately 0.14%.2 Furthermore, the most common type of neuropathic injury was brachial plexopathy.2 The patient experienced slow improvement of function with continued pain but unfortunately succumbed to the sequelae of his comorbidities without full recovery. Magnetic resonance imaging combined with electromyography/nerve conduction studies can aid in diagnosis when critical illness limits performance of a history and examination. In addition, magnetic resonance imaging may offer the ability to find injuries within 24 to 48 h of onset and differentiate high-grade lesions, which may necessitate surgical management. The American Society of Anesthesiologists (Schaumburg, Illinois) published the Practice Advisory for the Prevention of Perioperative Peripheral Neuropathies with the most recent update in 2018.3 The authors hope that performing a history and examination to identify risks, limiting arm abduction to 90 degrees, avoiding cervical rotation or extension, bracing shoulders to prevent cephalad motion, frequent reassessment, and protective padding, in addition to avoidance of hypotension and focus on glycemic control, can mitigate the risk of such potentially catastrophic nerve injuries. Competing Interests The authors declare no competing interests.