Abstract
Aim: For uniform assessment of occupational ulnar nerve entrapment at elbow (UNE) assessment methods using electrophysiological criteria were introduced in 2011. The study aimed at determining changes in selected EMG parameters in UNE recognized as occupational disease using the methods in 2012-2016.
Patients and methods: In 55 participants (49 males), follow-up EMG at 1 to 5 years from recognition as occupational disease was assessed. Eighty-one arms were affected by UNE.
Changes in the amplitude of motor nerve conduction velocity of the ulnar nerve across the elbow (MNCV-U) and in compound muscle action potential over the abductor digiti minimi (CMAP ADM) were compared with initial EMG. Results: The MNCV-U parameter remained unchanged in 54% of cases, deteriorated in 16% and improved in 30%.
The mean MNCV-U increased significantly between the measurements. The CMAP ADM amplitude was unchanged in 89% of cases, worse in 4% and better only in 7%.
Its mean value at follow-up was not statistically significantly different. There was no case of completely normalized EMG.
Conclusion: Occupational UNE is a chronic condition with an unsatisfactory prognosis even after the occupational risk is removed.