Assessing the effectiveness of suprascapular nerve block in the treatment of frozen shoulder

Aims: Frozen shoulder is a common and debilitating condition characterized by pain and restricted movement at the glenohumeral joint. Various treatment methods have been explored to alleviate symptoms, with suprascapular nerve block (SSNB) emerging as a promising intervention. This meta-analysis aimed to assess the effectiveness of SSNB in treating frozen shoulder.

Methods: The study protocol was registered with PROSPERO (CRD42023475851). We searched the MEDLINE, Embase, and Cochrane Library databases in November 2023. Randomized controlled trials (RCTs) comparing SSNB against other interventions were included. The primary outcome was any functional patient-reported outcome measure. Secondary outcomes were the visual analogue scale (VAS) for pain, range of motion (ROM), and complications. Risk of bias was assessed using the Cochrane risk of bias v. 2.0 tool.

Results: A total of 12 RCTs were identified (702 patients; mean age 55 years (30 to 72)). Eight RCTs were deemed "low" risk-of-bias and four raised "some concerns". Comparator interventions included intra-articular steroid injection (IAI), hydrodistension, physiotherapy, and placebo injection with 0.9% saline. Seven studies compared SSNB to IAI, with SSNB resulting in greater improvement in the Shoulder and Pain Disability Index (mean difference -4.75 (95% CI -8.11 to -1.39); p = 0.006) and external rotation (mean difference 11.64 (95% CI -0.05 to 23.33); p = 0.050). In three studies, SSNB demonstrated better VAS (mean difference -0.31 (95% CI -0.53 to 1.79); p = 0.004) compared to physiotherapy (with or without placebo injection). One study favoured hydrodistension over SSNB in improving ROM and VAS. There was no significant difference in outcomes between SSNB administered under ultrasound guidance or using a landmark technique.

Conclusion: SSNB can be administered in the outpatient clinic with promising outcomes compared to IAI or physiotherapy based on level I evidence. It can therefore be considered as a first-line treatment option.