The Modulatory Effect of Quantitative Sensory Testing in Shoulder Pain: A Systematic Review and Meta-Analysis

BACKGROUND: The underlying mechanisms for shoulder pain (SP) are still widely unknown. Previous reviews have reported signs of altered pain processing in SP measured with quantitative sensory testing (QST). Evidence suggests that QST might hold predictive value for SP after an intervention, yet it is not known whether QST profiles can be modulated in response to different treatments. Therefore, this systematic review and meta-analysis aimed to assess whether QST parameters can be modified by interventions for patients with SP. METHODS: Three databases were searched to identify eligible studies. Eligible studies had a prospective design, with at least one QST variable as an outcome in conjunction with an intervention measured before and after the intervention. Studies that involved SP caused by spinal or brain injury and studies looking at combined chronic neck pain and SP were excluded. RESULTS: Nineteen studies investigating SP were eligible for inclusion in this review. Pressure pain threshold (PPT) was the most frequently used QST parameter to investigate local and widespread hyperalgesia. A meta-analysis was performed on data from 10 studies with a total of 16 interventions. Results demonstrated an overall acute effect (<24 hours after intervention) of interventions in favor of local decreased pain sensitivity and remote decreased pain sensitivity when PPTs before and after interventions were compared. CONCLUSIONS: This study demonstrates that interventions such as exercise and manual therapy can modulate PPTs acutely, both locally and remotely, in patients with SP. Further research investigating the acute and long-term modulatory ability of these interventions on other QST parameters is needed in patients with SP.