Which regional nerve block is recommended for analgesia in an adult patient with a surgical proximal humeral neck fracture presenting to the emergency department?

Interscalene Brachial Plexus Block for Proximal Humeral Neck Fractures

For adult patients with surgical proximal humeral neck fractures presenting to the emergency department, perform an ultrasound-guided interscalene brachial plexus block as the primary regional anesthesia technique for analgesia.

Rationale and Evidence

The interscalene block provides superior analgesia for proximal humerus fractures by targeting the brachial plexus at the C5-C7 nerve roots, which innervate the shoulder region 1, 2. A systematic review of regional anesthesia for proximal humerus fracture repair demonstrated that regional anesthesia provides effective pain relief, reduces opioid consumption, decreases adverse events, shortens hospital stays, and improves functional outcomes compared to general anesthesia alone 2.

Technical Approach

Block Technique

• Use ultrasound guidance to identify the brachial plexus between the anterior and middle scalene muscles at the C6 level
• Employ nerve stimulation if available (sustained biceps motor response at 0.2 mA confirms proper needle placement) 1
• Administer 20-40 mL of local anesthetic using ropivacaine 0.5% (preferred agent due to lower systemic toxicity) or bupivacaine 0.25-0.5% 3, 1
• Expect surgical anesthesia within 15-20 minutes 1

Local Anesthetic Selection

Ropivacaine is the preferred agent because it demonstrates less systemic toxicity and causes less motor blockade than bupivacaine 3. For peripheral nerve blocks, use 0.5 to 1.5 mg/kg of ropivacaine or bupivacaine 3.

Multimodal Analgesia Framework

Do not rely on the nerve block alone. Implement the following concurrent analgesic strategy:

Immediate ED Management

1. Intravenous morphine titration (boluses of 2-3 mg every 5 minutes until pain controlled) for immediate pain relief while preparing the block 4
2. Paracetamol 1g IV - provides additive analgesia with opioids 4
3. Low-dose ketamine 0.15-0.3 mg/kg IV - improves analgesia and reduces morphine requirements 4

Avoid These Agents

• Do not use NSAIDs in the acute fracture setting due to concerns about bone healing and bleeding risk in surgical candidates 5
• Avoid intramuscular opioids - they cause injection pain and provide unreliable absorption 6
• Do not use codeine or tramadol - associated with constipation and perioperative cognitive dysfunction in older adults 5

Alternative and Adjunctive Blocks

When Interscalene Block May Be Insufficient

The shoulder region receives innervation from multiple sources beyond the brachial plexus, including the supraclavicular nerves (C3-C4) and intercostal nerves (T1-T2). For complete surgical anesthesia:

• Add superficial cervical plexus block to cover the supraclavicular region 7, 8
• Consider T2 thoracic paravertebral block if anterior surgical approach extends medially - this addresses the T1-T2 nerve distribution that interscalene blocks miss 7

Emerging Alternative: Erector Spinae Plane Block

The erector spinae plane block at T2-T3 level provides excellent analgesia for proximal humerus surgery with the significant advantage of sparing the phrenic nerve (avoiding hemidiaphragmatic paralysis that occurs in nearly 100% of interscalene blocks) 9. This may be preferable in patients with:

• Significant pulmonary disease
• Contralateral phrenic nerve dysfunction
• Morbid obesity

Critical Safety Considerations

Contraindications to Neuraxial/Regional Blocks

• Active coagulopathy or therapeutic anticoagulation 5
• Infection at injection site
• Patient refusal or inability to cooperate

Local Anesthetic Systemic Toxicity (LAST)

• Have 20% Intralipid immediately available: 1.5 mL/kg bolus over 1 minute, then 0.25 mL/kg/min infusion 3
• Monitor for CNS symptoms (confusion, seizures) and cardiovascular collapse (bradycardia, arrhythmias, asystole)
• Risk is low but higher with inadvertent intravascular injection

Phrenic Nerve Paralysis

Interscalene blocks cause ipsilateral hemidiaphragmatic paralysis in virtually all cases. This is usually well-tolerated but exercise caution in patients with:

• FEV1 <50% predicted
• Baseline hypercapnia
• Contralateral phrenic dysfunction

Practical Implementation

Perform the block in the ED before surgical consultation when possible - early regional anesthesia reduces pain scores, decreases total opioid consumption, and improves patient satisfaction 2. The block provides 12-24 hours of analgesia depending on the local anesthetic used and whether adjuvants like dexmedetomidine (1-2 mcg/kg) are added for prolonged duration 3.

For patients requiring operative fixation, coordinate with anesthesiology regarding whether to place a continuous catheter for extended postoperative analgesia versus relying on a single-shot block supplemented by systemic analgesics 6.