Guidelines for Interscalene Blocks in Shoulder Procedures

Regional Anesthetic Technique Recommendations

Continuous interscalene block is preferred over single-shot interscalene block due to longer duration of analgesia and reduced rebound pain 1, 2
Continuous interscalene blocks provide lower pain scores and reduced opioid consumption on postoperative days 1, 2, and 7 compared to single-shot blocks 2
Continuous interscalene blocks significantly reduce postoperative pain scores at 6h, 24h, and 72h as well as during physiotherapy compared to IV patient-controlled analgesia 3
If continuous interscalene block is not feasible, single-shot interscalene block should be used, but with awareness of its limited duration (6-8 hours) and potential for rebound pain at 24 hours 2, 4
If interscalene block is contraindicated, an axillary nerve block with or without suprascapular nerve block is recommended over no block or suprascapular nerve block alone 5

Optimizing Interscalene Block Efficacy

Intravenous dexamethasone is recommended to increase the analgesic duration of interscalene block and decrease supplemental analgesia requirements 1, 2
Perineural adjuncts such as buprenorphine, tramadol, or magnesium sulphate have limited procedure-specific evidence and are not routinely recommended 2, 4
Perineural glucocorticoids (betamethasone and dexamethasone) have limited evidence; intravenous dexamethasone is preferred over perineural administration 4, 6
Regular administration of paracetamol and NSAIDs or COX-2 inhibitors is imperative to avoid significant pain after regional block resolution 2
Multimodal analgesia should be initiated pre-operatively or intra-operatively and continued into the postoperative period 2, 4
Arthroscopic approach is recommended over open procedures when possible as it reduces postoperative pain 2

Technical Considerations and Monitoring

For continuous interscalene block, ropivacaine 0.2-0.3% is effective, with higher concentrations (0.3%) potentially providing better opioid-sparing effects 3
Continuous interscalene block with patient-controlled bolus capability may provide better analgesia than fixed-rate infusion alone 3

Post-Operative Pain Management in Shoulder Surgery

Interscalene Brachial Plexus Block

The PROSPECT guidelines recommend interscalene brachial plexus blockade as the first-choice regional analgesic technique for pain management after rotator cuff repair and shoulder surgeries, with a high success rate and low complication rates 7, 8
Interscalene blocks are specifically indicated for post-operative pain control in shoulder surgeries, such as right revision of hemiarthroplasty to anatomic total shoulder arthroplasty, and meet Aetna's CPB criteria for medical necessity 9
Continuous or single-shot interscalene blocks reduce postoperative pain scores and opioid consumption, with significant benefits on postoperative days 1, 2, and 7 10, 11
Effective pain control from interscalene blocks can improve early postoperative rehabilitation and potentially improve long-term outcomes, according to the American Society of Anesthesiologists 12

PECS II Block

The PECS II block is explicitly listed as "not medically necessary or unproven" in Aetna's CPB criteria for post-operative pain control after shoulder surgery, and is not recommended by the PROSPECT guidelines 9
The PROSPECT guidelines do not include PECS II block among their recommended regional analgesic techniques for shoulder surgery, citing insufficient evidence to support its use 7, 8, 13
The American College of Surgeons recommends interscalene block as first-line, or suprascapular nerve block as an alternative, but makes no mention of PECS II block for shoulder procedures 8, 12

Recommended Pain Management Approach

The optimal analgesic regimen for shoulder surgery should include interscalene brachial plexus block, systemic analgesia with paracetamol and NSAIDs/COX-2 inhibitors, a single dose of IV dexamethasone, and opioids reserved for rescue analgesia only, according to the American Pain Society 7, 8, 12, 13
If interscalene block is contraindicated, suprascapular nerve block (with or without axillary nerve block) would be the appropriate alternative, not PECS II block, as recommended by the American Society of Regional Anesthesia and Pain Medicine 8, 14

Ideal Concentration of Bupivacaine for Interscalene Block in Shoulder Surgery

Evidencia de Concentraciones Específicas

The American Society of Anesthesiologists recommends concentrations of 0.2-0.3% for continuous infusion, which are more suitable than 0.25% for prolonged use, as they provide effective analgesia while minimizing motor block 15

Consideraciones Prácticas Importantes

The European Society of Anaesthesiology suggests that for continuous infusion, concentrations of 0.2-0.3% are more appropriate than 0.25% for prolonged use, as they provide effective analgesia while minimizing motor block 15
A concentration of 0.3% reduces opioid consumption at all time points during the first 48 hours, although pain scores were similar, according to the Anaesthesia journal 15

Evidence‑Based Recommendations for Ultrasound‑Guided Interscalene Block in Arthroscopic Bankart Repair

Analgesic Efficacy and Duration

A single‑shot ultrasound‑guided interscalene block using 20–25 mL of 0.5 % long‑acting amide local anesthetic provides complete surgical anesthesia and postoperative analgesia lasting 6–8 hours, with significantly lower pain scores and opioid consumption compared with systemic analgesia alone. 16
The same block technique yields a predictable onset time of 14–22 minutes and maintains effective analgesia throughout the early postoperative period. 17

Adjunctive Intravenous Dexamethasone

Adding 4 mg intravenous dexamethasone at the time of block placement prolongs the duration of analgesia and reduces the need for supplemental analgesics during the first 48 hours after surgery. 17
Intravenous dexamethasone is preferred over perineural administration because it provides equivalent analgesic benefit without the theoretical risks associated with perineural injection. 17

Multimodal Analgesia Strategy

Initiating scheduled acetaminophen and NSAIDs (or COX‑2 inhibitors) pre‑operatively or intra‑operatively, and continuing them post‑operatively, prevents rebound pain when the block resolves and minimizes opioid requirements. 16

Continuous vs. Single‑Shot Interscalene Block

A continuous interscalene block is superior to a single‑shot technique for reducing rebound pain and providing analgesia throughout postoperative days 1–3 and beyond, although it adds logistical complexity for outpatient procedures. 16

Evidence Summary

Guideline Recommendations for Analgesia and Alternative Nerve Blocks in Shoulder Surgery

Multimodal Systemic Analgesia

Initiate scheduled paracetamol together with non‑steroidal anti‑inflammatory drugs (or selective COX‑2 inhibitors) before or during the operation and continue them post‑operatively to prevent significant rebound pain after the regional block wears off in patients undergoing shoulder or proximal humerus surgery. 18

Opioid Stewardship

Reserve opioid medications exclusively for rescue analgesia when breakthrough pain occurs despite the multimodal regimen in shoulder surgery patients. 18

Alternative Nerve‑Block Strategies When Interscalene Block Is Contra‑indicated

Employ a suprascapular nerve block, with or without an additional axillary nerve block, as the recommended alternative technique for shoulder procedures when an interscalene block cannot be performed; this approach provides superior analgesic coverage compared with not performing any regional block. 18

Supra‑Scapular Nerve Block – Guideline Summary

Indications

For patients undergoing shoulder surgery in whom an interscalene block is contraindicated, a supra‑scapular nerve block is recommended as an alternative analgesic technique for peri‑operative pain and for chronic degenerative or rheumatologic shoulder pain. 19
In the peri‑operative setting, a supra‑scapular block combined with an axillary nerve block provides postoperative analgesia after shoulder arthroscopy and rotator‑cuff repair. 19
A solitary supra‑scapular block alone yields incomplete analgesia for shoulder surgery; therefore it should be combined with an axillary nerve block to achieve optimal coverage. 19

Technique Recommendations

Ultrasound guidance is advised for all peripheral nerve blocks near the head and neck, including the supra‑scapular block, to reduce the risk of systemic local‑anesthetic toxicity. 20
Calculating a safe local‑anesthetic dose and confirming real‑time spread of the injectate under ultrasound further minimizes systemic toxicity. 20

Safety and Risk Mitigation

Strict aseptic technique during the supra‑scapular block minimizes infection risk. 20
When performing the block on patients with suspected or confirmed COVID‑19, both droplet and airborne precautions should be employed to prevent viral transmission. 20
The supra‑scapular block does not cause sympathetic blockade or hypotension, unlike interscalene techniques, providing a hemodynamic safety advantage. 20
The block does not impair respiratory function, offering an important safety benefit over interscalene blockade. 20