Ultrasound-Guided PENG Block for Chronic Shoulder Pain

Study Design and Setting:

This is a prospective, observational, and single-center clinical study designed to evaluate the clinical and functional outcomes of ultrasound-guided Pericapsular Nerve Group (PENG) block in patients with chronic shoulder pain. The study will be conducted in accordance with the Declaration of Helsinki, and approval from the local clinical research ethics committee will be obtained prior to patient enrollment.

Patient Selection:

Adult patients (aged over 18 years) presenting with chronic shoulder pain lasting longer than 3 months, who have an initial Numerical Rating Scale (NRS) score greater than 4 and have not responded to conservative or medical treatments, will be screened for eligibility. Written informed consent will be obtained from all participating individuals. Patients with coagulation disorders, psychomotor disorders, active infections at the injection site, a history of shoulder surgery within the past 6 months, or known allergies to local anesthetics or corticosteroids will be excluded.

Intervention Protocol:

The ultrasound-guided shoulder PENG block is performed as a routine treatment modality in our clinic for patients non-responsive to conservative therapies. The procedure is conducted under sterile conditions with the patient in the supine position. The affected shoulder is placed in abduction and external rotation. An ultrasound transducer is positioned parallel to the clavicle to visualize the anatomical structures. A block needle is advanced under the subscapularis muscle under direct ultrasound guidance. Following the confirmation of correct needle positioning, a mixture of 5 mL of 2% lidocaine and 8 mg of dexamethasone is injected into the periarticular nerve endpoints. Outcome Measurements and Data Collection:

Demographic and clinical data will be collected by an expert algologist using the hospital information management system and recorded into dedicated study forms. Clinical parameters will be evaluated at four distinct time points: baseline (pre-procedure), 1st week, 4th week (1 month), and 3rd month post-procedure. Pain severity will be measured using the Numerical Rating Scale (NRS). Shoulder joint function and disability levels will be assessed using the Shoulder Pain and Disability Index (SPADI). Overall patient satisfaction and perceived improvement will be tracked via the Global Perceived Effect (GPE) scale.

Friedman test, depending on the distribution properties. Bonferroni correction will be applied for post-hoc pairwise comparisons, and a p-value less than 0.05 will be considered statistically significant.