Abstract
BACKGROUND: Chronic shoulder pain occurs rarely after a vaccination and is hypothesized to arise from the effects of unintentional vaccine injection into the subacromial bursa, rotator cuff, capsule or underlying bone. The avascular nature of the rotator cuff, as well as unknown genetic and environmental factors, may predispose to the persistence of pain and disability, referred to as vaccination-related shoulder dysfunction and shoulder injury related to vaccine administration (SIRVA). METHODS: Ultrasonography, sonopalpation and ultrasound-guided anesthetic injections were used to locate the anatomical source of chronic (mean 20, range 8-42 months) shoulder pain after a vaccination in a consecutive series of 5 patients. Subsequently ultrasound-guided ultrasonic aspiration and debridement was performed using a 2.1 mm outer cannula with an inner needle vibrating at 28 kHz. Outcomes were assessed using the Quick Disabilities of the Arm, Shoulder and Hand (QDASH) scale at 2, 4, 12, 24 weeks and 1 year. RESULTS: The distal infraspinatus and teres minor tendons, their insertions and or the adjacent bone were the source of pain in all 5 patients. The mean QDASH score improved from 65 points to 11 points at 2 weeks (P = 0.001), and to 1 point at 4 weeks after the procedures (P = 0.003). Improvements in pain and function remained stable at 1 year in 3 patients, for at least 24 weeks in 1 patient who died of unrelated causes, and 1 year in 1 patient for posterior shoulder pain who after a pain free interval developed anterior shoulder pain related to his previously asymptomatic osteoarthritis (P = 0.013). CONCLUSION: The distal infraspinatus and teres minor tendons, their insertions and adjacent bone are a common source of chronic shoulder pain after a vaccination. Ultrasound-guided ultrasonic aspiration and debridement is a potentially effective treatment for resolving pain and restoring function.