Upper extremity nerve involvement in Swedish female machine milkers

Area of Science:

• Occupational Medicine
• Neurology
• Hand Surgery

Background:

• Pronator syndrome, median nerve entrapment in the forearm, is uncommon but affects women more frequently.
• Machine milkers often present with forearm and hand symptoms, suggesting a potential occupational link.

Purpose of the Study:

• To investigate the prevalence and clinical presentation of pronator syndrome in female machine milkers.
• To evaluate the effectiveness of surgical intervention for pronator syndrome in this occupational group.

Main Methods:

• Clinical diagnosis of pronator syndrome in 30 female machine milkers based on history and physical examination.
• Objective muscle strength testing using Mannerfeldt's intrinsicmeter to quantify weakness in specific forearm muscles.
• Surgical nerve release for 8 patients with confirmed pronator syndrome.

Main Results:

• 23 out of 30 milkers were diagnosed with pronator syndrome, presenting with forearm aching, hand numbness, tingling, and decreased muscle strength.
• Objective testing revealed weakness in pronator teres (PT), flexor carpi radialis (FCR), flexor pollicis longus (FPL), and flexor digitorum profundus II (FDP II).
• Post-surgical release, 8 patients experienced significant symptom relief, with one requiring subsequent carpal tunnel surgery.

Conclusions:

• Machine milking may involve occupational exposures leading to muscle and fascial tension, potentially causing median nerve compression (pronator syndrome).
• Surgical decompression is an effective treatment for pronator syndrome in machine milkers.
• Further research is necessary to elucidate the specific internal exposure mechanisms involved.