Shoulder arthroscopy is a minimally invasive procedure frequently used for rotator cuff repair. Patients may experience severe postoperative (PO) pain, that can last for a month and can influence successful rehabilitation. Our study aimes to evaluate the effectiveness of interscalene brachial plexus single-shot (ISBSS) versus continuous interscalene brachial plexus block (ISBC) in controlling perioperative pain and avoiding PO pain chronicization. This prospective randomized unblinded trial hypothesizes that the PO perineuronal infusion using a continuous ambulatory delivery device pump gives better pain control and outcomes than ISBSS during the long-term follow-up period.

Blocks will be performed under ultrasound guidance with 15 - 20 mL of 0.75 % ropivacaine.

Inclusion Criteria:

• American Society of Anesthesia (ASA) physical status of 1 to 2,
• Body Mass Index (BMI) of less than 30 kg/m²,
• paitents undergoing shoulder arthroscopy for small to medium rotator cuff tears.

Exclusion Criteria:

• skin infection on the puncture site,
• coagulopathy
• brachial plexus neuropathy
• alcohol or drug abuse
• diabetes
• severe lung disease
• history of allergy to one or more study drugs.