The Unpredictable Ulnar Nerve—Ulnar Nerve Entrapment from Anatomical, Pathophysiological, and Biopsychosocial Aspects

Abstract

Peripheral nerves consist of delicate structures, including a rich microvascular system, that protect and nourish axons and associated Schwann cells. Nerves are sensitive to internal and external trauma, such as compression and stretching. Ulnar nerve entrapment, the second most prevalent nerve entrapment disorder after carpal tunnel syndrome, appears frequently at the elbow. Although often idiopathic, known risk factors, including obesity, smoking, diabetes, and vibration exposure, occur. It exists in all adult ages (mean age 40–50 years), but seldom affects individuals in their adolescence or younger. The patient population is heterogeneous with great co-morbidity, including other nerve entrapment disorders. Typical early symptoms are paresthesia and numbness in the ulnar fingers, followed by decreased sensory function and muscle weakness. Pre- and postoperative neuropathic pain is relatively common, independent of other symptom severity, with a risk for serious consequences. A multimodal treatment strategy is necessary. Mild to moderate symptoms are usually treated conservatively, while surgery is an option when conservative treatment fails or in severe cases. The decision to perform surgery might be difficult, and the outcome is unpredictable with the risk of complications. There is no consensus on the choice of surgical method, but simple decompression is relatively effective with a lower complication rate than transposition.

Presurgical management of ulnar nerve entrapment in patients with and without diabetes mellitus

“…In a recent study, we found the opposite in carpal tunnel syndrome; individuals with type 1 DM were more likely to be surgically treated than individuals with type 2 DM 32 . These findings may reflect the pathoanatomical differences in CTS and UNE 33 , or perhaps a slightly different risk factor panorama in the different types of diabetes. We also hypothesized that a long duration of diabetes would be associated with a higher risk of surgical treatment due to the higher risk of neuropathy, but it was only borderline significant in the regression analysis.…”