Experience With Proximal Median Nerve Entrapment by the Lacertus Fibrosus

Area of Science:

• Neurology
• Orthopedic Surgery

Background:

• Clinician unconscious bias may favor carpal tunnel syndrome (CTS) diagnosis in patients with median paresthesia.
• Proximal median nerve entrapment (PMNE) is a potential alternative diagnosis that may be overlooked.
• Cognitive bias mitigation strategies were implemented to increase PMNE diagnosis rates.

Purpose of the Study:

• To investigate the impact of heightened cognitive awareness on diagnosing PMNE.
• To evaluate the efficacy of surgical release of the lacertus fibrosus (LF) for treating PMNE.

Main Methods:

• Retrospective study analyzing median nerve decompression cases before and after bias mitigation strategies.
• Evaluation of patients diagnosed with PMNE and treated with LF release.
• Assessment of surgical outcomes, including changes in median paresthesia and muscle strength, at a minimum 2-year follow-up.

Main Results:

• A statistically significant increase in identified PMNE cases was observed after implementing heightened surveillance (z = 3.433, P < .001).
• 10 out of 12 patients with PMNE had prior carpal tunnel release (CTR) with recurrent symptoms.
• 8 patients treated with LF release showed improvement in median paresthesia and muscle strength after an average of 5 years.

Conclusions:

• Cognitive bias can lead to PMNE misdiagnosis as CTS.
• All patients with median paresthesia, especially post-CTR, require assessment for PMNE.
• Surgical release of the LF may be an effective treatment for PMNE.