Peripheral Nerve Blocks: Upper Extremity

Upper Limb Blocks - Nerve Navigator Intro

• Regional anesthesia for upper extremity surgery and pain management.
• Indications: Procedures on shoulder, arm, forearm, hand.
• Techniques: Single-shot or continuous catheter.
• Benefits: Opioid-sparing, ↓PONV, improved recovery.
• Risks: Nerve injury, LAST, hematoma, infection. ⚠️ Pneumothorax (supraclavicular).
• Ultrasound guidance standard for precision and safety.

⭐ Supraclavicular block: "Spinal of the arm" for comprehensive brachial plexus blockade.

Brachial Plexus - Anatomy Highway

• Roots (C5, C6, C7, C8, T1): Between Anterior & Middle Scalenes.
• Trunks (Superior, Middle, Inferior): Posterior triangle of neck, above clavicle.
• Divisions (Anterior/Posterior each): Deep to clavicle, enter axilla.
• Cords (Lateral, Posterior, Medial): Axilla; named by relation to axillary artery.
• Branches (Terminal & Collateral): Innervate the upper limb.

📌 Mnemonic: Randy Travis Drinks Cold Beer.

⭐ Upper Trunk (C5,C6) injury results in Erb's Palsy (waiter's tip deformity).

Above the Clavicle - High & Mighty Blocks

• Interscalene Block (ISB):
  • Targets: Roots/Trunks (C5-C7).
  • Landmark: Interscalene groove.
  • Use: Shoulder, clavicle, proximal humerus. 📌 InterScalene for Shoulder.
  • ⚠️ High phrenic nerve palsy risk; ulnar sparing.
• Supraclavicular Block (SCB):
  • Targets: Trunks/Divisions. 📌 Spinal of the arm.
  • Landmark: Above clavicle midpoint.
  • Use: Arm, forearm, hand (below shoulder).
  • ⚠️ Highest pneumothorax risk; phrenic palsy (~50%).

⭐ Phrenic nerve palsy (nearly 100%) is an expected side effect of Interscalene block due to nerve proximity at this level of the brachial plexus.

Below Clavicle & Axilla - Lowdown & Localized

• Infraclavicular Block

  • Targets: Cords (Lateral, Posterior, Medial).
  • Approach: Inferior to clavicle, medial to coracoid.
  • Covers: Arm, elbow, forearm, hand. Phrenic sparing.
  • Catheter: Good stability.
  • USG: Cords around axillary artery.

• Axillary Block

  • Targets: Branches (Median, Ulnar, Radial, Musculocutaneous).
  • Approach: Axilla, around axillary artery.
  • Covers: Forearm, hand.
  • ⚠️ Musculocutaneous nerve (MCN) often requires separate block in coracobrachialis.
  • USG: Nerves around axillary artery ("honeycomb").

  ⭐ Axillary block is a common choice for distal upper limb surgery, especially if avoiding phrenic nerve palsy is critical.

Distal Delights - Forearm & Wrist Wizards

• Elbow:
  • Median N: Medial to brachial artery.
  • Ulnar N: Ulnar groove.
  • Radial N: Lateral to biceps tendon.
• Wrist: (Hand/finger anesthesia)
  • Median N: B/w Palmaris Longus & FCR.
  • Ulnar N: Lat. to FCU, Med. to ulnar artery.
  • Sup. Radial N: Anatomical snuffbox.

⭐ Wrist blocks: Ideal for carpal tunnel release, trigger finger; spares forearm motor function.

Tech & Tox - Tools & Troubleshooters

• Tools:
  • Ultrasound (USG): Preferred for ↑success, ↓complications. In-plane/out-of-plane views.
  • Nerve Stimulator: Motor response at <0.5 mA (e.g., 0.2-0.4 mA). Echogenic needles.
  • Local Anesthetics (LAs): Lignocaine, Bupivacaine.
  • Adjuvants: Epinephrine (↑duration), Dexamethasone.
• Troubleshooters (Tox):
  • LAST (Local Anesthetic Systemic Toxicity): CNS (tinnitus, seizures), CVS (arrhythmias, arrest).

    ⭐ Lipid Emulsion 20%: Bolus 1.5 mL/kg, then 0.25 mL/kg/min infusion.

  • Nerve injury, Hematoma, Infection.
  • ⚠️ Pneumothorax (esp. Supraclavicular block).

High‑Yield Points - ⚡ Biggest Takeaways

• Interscalene block: High incidence of phrenic nerve palsy; ideal for shoulder surgery.
• Supraclavicular block: "Spinal of the arm"; highest pneumothorax risk; covers arm, elbow, forearm, hand.
• Infraclavicular block: Spares phrenic nerve; good for distal arm/hand surgery; stable for catheters.
• Axillary block: Safest from pneumothorax; best for forearm/hand; musculocutaneous nerve often needs separate block.
• Bier's block (IVRA): Uses double tourniquet; risk of LAST with tourniquet failure; for short procedures.
• Ultrasound guidance is standard for ↑success and ↓complications like nerve injury or LAST (Local Anesthetic Systemic Toxicity).