Diagnostic Approach and Management of Ulnar Nerve Entrapment

Diagnostic Methods

MRI without IV contrast is the reference standard for imaging ulnar nerve entrapment, with T2-weighted MR neurography showing high signal intensity and nerve enlargement, according to the American College of Radiology 1
Ultrasound is an effective alternative with high accuracy rates (sensitivity 77-79%, specificity 94-98%) for assessing cross-sectional area and nerve thickness, as recommended by the American College of Radiology 1
Shear-wave elastography has shown 100% specificity and sensitivity for diagnosing ulnar neuropathy at the elbow, as reported by the American College of Radiology 1

The American Society of Anesthesiologists recommends maintaining neutral forearm position when arm is tucked at side, using supinated or neutral forearm position when arm is abducted on an armboard, and limiting arm abduction to 90° in supine position to prevent ulnar nerve entrapment 2
The American Society of Anesthesiologists suggests avoiding prolonged pressure on the postcondylar groove of the humerus (ulnar groove) to prevent ulnar nerve entrapment 2
Paracetamol (up to 4g/day) is recommended as first-line oral analgesic for pain management, according to Praxis Medical Insights 3
Topical NSAIDs are recommended for localized pain with fewer systemic side effects, as suggested by Praxis Medical Insights 3
Oral NSAIDs are recommended at lowest effective dose for shortest duration if inadequate response to paracetamol, according to Praxis Medical Insights 3
Range of motion and strengthening exercises are recommended to maintain function, as suggested by Praxis Medical Insights 3
Local heat application before exercise is recommended, according to Praxis Medical Insights 3

The American Society of Anesthesiologists recommends avoiding excessive elbow flexion beyond 90° as this may increase risk of ulnar neuropathy 2
Periodic assessment of upper extremity position during procedures is essential to prevent complications, as recommended by the American Society of Anesthesiologists 2

Differentiation between demyelinating vs. axonal injury can be made through nerve conduction studies, which is secondary to localization for treatment planning, as per the American Academy of Neurology 4
Prognosis assessment can be determined through nerve conduction studies, which is less important than localization for initial management, with a moderate level of evidence, as recommended by the American College of Rheumatology 5
Electromyography with nerve conduction studies can identify axonal degeneration through reduced sensory nerve action potential amplitude, which is a diagnostic criterion for ulnar neuropathy, as stated by the American Association of Neuromuscular and Electrodiagnostic Medicine 4
Follow-up monitoring strategies are determined by the location and severity of the lesion, which can be assessed through nerve conduction studies, with a high level of evidence, as recommended by the American College of Rheumatology 5

The American Society of Anesthesiologists indicates that shoulder braces or shoulder immobilizers applied in inappropriate positions may increase the risk of brachial plexus neuropathy. (expert consensus) 6, 7, 8

The ASA Task Force reported that 66 % of its consultants and members agree that shoulder braces positioned over the acromioclavicular joint may raise the risk of neuropathy. (expert consensus) 6, 7