What are the recommended peripheral nerve block choices and combinations for a patient undergoing open reduction and internal fixation (ORIF) plating for a fracture dislocation of the proximal humerus?

Peripheral Nerve Block for Proximal Humerus ORIF

Primary Recommendation

For open reduction and internal fixation of proximal humerus fracture-dislocation, use an interscalene brachial plexus block as the primary regional anesthetic technique, combined with general anesthesia, while implementing strict respiratory monitoring protocols due to inevitable phrenic nerve involvement. 1

Block Selection Algorithm

First-Line: Interscalene Brachial Plexus Block

• Provides complete surgical anesthesia for the shoulder joint, proximal humerus, and surgical field required for ORIF plating 1
• Use 20-30 mL of 0.25-0.5% bupivacaine, 0.25% levobupivacaine, or 0.5% ropivacaine under ultrasound guidance 2, 3
• Maximum safe dosing: 2.5 mg/kg for bupivacaine 0.25% and 3 mg/kg for ropivacaine 0.2% 2
• Always use ultrasound guidance to reduce risk of local anesthetic systemic toxicity 4, 3

Alternative Phrenic-Sparing Approaches (Second-Line)

If respiratory compromise is a major concern (COPD, contralateral phrenic palsy):

• Superior trunk block may be considered as it provides partial phrenic sparing while maintaining adequate shoulder coverage 4
• Supraclavicular block is NOT recommended as it still causes significant phrenic nerve blockade and provides inferior surgical field coverage 4
• Axillary or infraclavicular approaches are contraindicated as they do not provide adequate shoulder joint innervation 4

Critical Respiratory Management

Mandatory Monitoring

• Continuous pulse oximetry, ECG, and non-invasive blood pressure throughout the procedure 1, 3
• Supplemental oxygen should always be provided, particularly in patients with COPD or baseline respiratory compromise 4, 1
• Expect 100% phrenic nerve paresis with interscalene block; this is unavoidable but temporary 1

High-Risk Patient Modifications

• In patients with severe COPD (FEV1 <50%), contralateral phrenic palsy, or morbid obesity, strongly consider general anesthesia alone with multimodal systemic analgesia rather than regional block 1
• Reduce sedation doses to avoid respiratory compromise if combining block with sedation 4

Adjunct Analgesia (Mandatory Components)

Baseline Multimodal Regimen

• Paracetamol (acetaminophen) 1000 mg every 6 hours as first-line medication 1
• NSAIDs/COX-2 inhibitors if not contraindicated, with 20-25% dose reduction per decade after age 55 1
• Peripheral nerve blockade should never be used as monotherapy; always combine with systemic agents 2

Rescue Opioid Strategy

• Carefully titrated intravenous morphine preferred over oral or intramuscular routes 4
• Avoid codeine and tramadol due to adverse effects including constipation and perioperative cognitive dysfunction 4
• Use IV PCA with strong opioids rather than intramuscular administration if needed 2

Adjuvant Selection (Critical Safety Considerations)

Avoid These Adjuvants

• Do NOT use ketamine in elderly patients due to significant risk of postoperative confusion and delirium 1
• Do NOT use clonidine as adjuvant due to hypotension, sedation, and bradycardia risks 1
• Avoid long-acting benzodiazepines entirely in patients over 60 years as they are strongly associated with postoperative delirium 1

Acceptable Perineural Adjuvants

• Dexamethasone may be considered but balance against immunosuppression risk 4, 3
• In pediatric cases only: preservative-free clonidine 1-2 mcg/kg 2

Anesthetic Technique Integration

Combined Regional-General Approach

• Peripheral nerve blockade should be considered in all cases as adjunct to general anesthesia 4
• Perform block before induction to allow adequate onset time (minimum 20-30 minutes) and reduce conversion risk 3
• Thoroughly test block success before surgical incision to minimize emergent conversion to deeper general anesthesia 4, 3

General Anesthesia Considerations

• Reduced doses of intravenous induction agents should be administered in elderly patients 4
• The Working Party does not support opioid analgesics as sole adjunct to anesthesia due to respiratory depression and postoperative confusion risk 4
• Avoid simultaneous neuraxial and general anesthesia as this combination is associated with precipitous hypotension 4

Surgical-Specific Considerations

Nerve Injury Risk Factors

• Low BMI (mean 22.7 ± 2.8), history of cervical spine disease, diabetes mellitus, and surgical delay >14 days are associated with increased intraoperative nerve dysfunction during proximal humerus ORIF 5
• The axillary nerve (46%), combined plexopathy (23%), and radial nerve (23%) are most commonly affected during surgical manipulation 5
• Consider intraoperative nerve monitoring in high-risk patients to prevent iatrogenic injury 5

Positioning and Block Timing

• Avoid blocks requiring patient repositioning if performed under general anesthesia due to risk of tracheal tube disconnection 4
• Interscalene block can be performed in supine position, making it ideal for this surgical approach 4

Common Pitfalls to Avoid

1. Performing block without ultrasound guidance increases local anesthetic systemic toxicity risk 4, 3
2. Inadequate onset time before surgical incision leads to failed blocks and emergent conversion 3
3. Excessive sedation in elderly patients causes respiratory compromise and delirium 4, 1
4. Using oral opioids or codeine in elderly patients increases constipation and cognitive dysfunction 4
5. Omitting baseline paracetamol and NSAIDs reduces overall analgesic efficacy and increases opioid requirements 1, 2