What is the role of a Peng block in managing shoulder pain?

Role of PENG Block in Managing Shoulder Pain

The PENG (pericapsular nerve group) block is not established as a primary intervention for shoulder pain management but may be considered as an alternative analgesic technique for selected shoulder surgeries when traditional approaches like interscalene brachial plexus blocks are contraindicated due to respiratory concerns.

Current Evidence-Based Approaches for Shoulder Pain

• Suprascapular nerve blocks are recommended as an adjunctive treatment for hemiplegic shoulder pain, with evidence showing they can reduce pain for up to 12 weeks compared to placebo injections 1
• Botulinum toxin injections into shoulder muscles (particularly pectoralis major, infraspinatus, and subscapularis) can be useful to reduce severe hypertonicity in hemiplegic shoulder muscles and associated pain 1
• Corticosteroid injections (glenohumeral or subacromial) show mixed results but may provide short-term pain reduction, particularly when shoulder joint pathology is verified by ultrasonography 1

Emerging Role of PENG Block

• PENG block has been investigated as an alternative to interscalene brachial plexus block for shoulder surgery to avoid hemidiaphragmatic paresis 2
• Current evidence suggests PENG block can provide effective analgesia for shoulder procedures without causing motor block or pulmonary complications 2
• However, PENG block alone is not sufficient for complete surgical anesthesia and should be considered as part of a multimodal approach 2

Alternative Nerve Blocks for Shoulder Pain

• Suprascapular nerve blocks have stronger evidence and are specifically mentioned in guidelines for hemiplegic shoulder pain management 1
• Erector spinae plane (ESP) block at T2/T3 level has shown promise in managing chronic shoulder pain with immediate and profound analgesia plus improved range of motion 3
• Suprascapular nerve blocks have demonstrated effectiveness in postoperative pain management for arthroscopic shoulder surgery, reducing opioid consumption by 31% and hospital stay by 24% 4

Clinical Decision Algorithm for Shoulder Pain Management

1. First-line approaches:

   • Patient education on positioning and range of motion exercises 1
   • Analgesics such as acetaminophen or ibuprofen if no contraindications 1

2. For spasticity-related shoulder pain:

   • Botulinum toxin injections into affected muscles (subscapularis, pectoralis) 1

3. For inflammatory/structural shoulder pain:

   • Subacromial corticosteroid injections when inflammation of subacromial region is suspected 1
   • Suprascapular nerve blocks for both hemiplegic and non-hemiplegic shoulder pain 1, 4

4. For perioperative shoulder pain management:

   • Consider PENG block as an alternative to interscalene block when respiratory concerns exist 2
   • Suprascapular nerve blocks for postoperative pain management 4

Pitfalls and Caveats

• PENG block is relatively new with limited evidence specifically for shoulder pain management compared to more established techniques 2
• Overhead pulley exercises are explicitly not recommended for shoulder rehabilitation after stroke 1
• Corticosteroid injections provide only short-term relief and long-term pain reduction has not been verified 1
• When selecting nerve blocks, consider that the suprascapular nerve supplies approximately 70% of sensory innervation to the shoulder joint 4

Special Considerations

• For hemiplegic shoulder pain after stroke, a comprehensive approach including proper positioning, supportive devices, and range of motion exercises should accompany any nerve block interventions 1
• For patients with central pain components (sensory changes, allodynia, hyperpathia), neuromodulating medications may be more appropriate than nerve blocks 1