What is the best erector spinae plane (ESP) block level for median sternotomy incision pain coverage?

Optimal Erector Spinae Plane Block Level for Median Sternotomy Pain Coverage

The optimal level for erector spinae plane (ESP) block in median sternotomy is at the T4 level, which provides effective coverage of the sternotomy incision while balancing analgesic spread and technical feasibility. 1, 2, 3

Evidence for ESP Block in Sternotomy Pain Management

• ESP blocks performed at the T3-T4 level have demonstrated significant reduction in pain scores and opioid consumption following cardiac surgery via median sternotomy 1, 2
• Bilateral ESP blocks at T4-T5 level significantly decreased morphine consumption in the first 24 hours postoperatively in pediatric cardiac surgery patients 3
• ESP blocks provide effective analgesia by targeting the dorsal and ventral rami of thoracic spinal nerves that innervate the sternum and surrounding tissues 1

Technical Considerations for Level Selection

• T4 level is optimal because:
  • It provides coverage of the T2-T6 dermatomes which encompass the entire sternotomy incision area 2
  • The transverse process is easily identifiable with ultrasound at this level 3
  • This level allows for adequate spread of local anesthetic to cover the median sternotomy incision 1

Block Technique and Local Anesthetic Selection

• Ultrasound-guided bilateral ESP blocks should be performed with the patient in sitting or lateral position 1, 2
• A high-frequency linear ultrasound probe identifies the transverse process at T4 level 3
• Local anesthetic options include:
  • 0.25-0.5% bupivacaine (0.5 mL/kg per side) for pediatric patients 2, 3
  • 20 mL of 0.25-0.5% bupivacaine or ropivacaine per side for adult patients 1

Clinical Outcomes with T4 Level ESP Block

• ESP blocks at T4 level for sternotomy have demonstrated:
  • Reduced intraoperative opioid requirements (4.3 ± 1.9 μg/kg vs 6.7 ± 3 μg/kg of fentanyl) 2
  • Delayed time to first rescue analgesia (231.6 ± 104.5 vs 108.8 ± 47.8 minutes) 2
  • Lower postoperative pain scores during the first 10 hours after extubation 1
  • Reduced ICU stay compared to conventional analgesia 1

Potential Pitfalls and Limitations

• ESP block efficacy may vary between patients due to anatomical differences and local anesthetic spread 4
• A meta-analysis showed inconsistent results regarding ESP block effectiveness for sternotomy pain, highlighting the need for proper technique and level selection 4
• Single-injection blocks may have limited duration (typically 12-24 hours), so consider catheter placement for prolonged analgesia 5
• Alternative approaches like superficial parasternal intercostal plane blocks have shown limited efficacy compared to ESP blocks 5

Alternative Block Levels

• While T4 is optimal, T3 level has also shown efficacy in some studies 1
• Multiple injections (from T4 to T8) have not demonstrated superior analgesia compared to a single injection at T4-T6 level and increase procedural time and discomfort 6
• ESP blocks performed too low (below T6) may not adequately cover the upper portion of the sternotomy incision 1, 2