At which vertebral level should the erector spinae plane (ESP) block be performed for a middle‑aged patient with well‑controlled hypothyroidism, hypertension treated with losartan, and borderline renal function undergoing a transforaminal lumbar interbody fusion (TLIF) at L4‑L5 and L5‑S1?

ESP Block Level for TLIF L4-L5 and L5-S1

Perform the erector spinae plane (ESP) block at the T10 or T12 vertebral level for TLIF procedures at L4-L5 and L5-S1.

Recommended Injection Level

The optimal level for ESP block in lumbosacral spine surgery is at the lower thoracic spine (T10-T12), which provides adequate coverage for L4-L5 and L5-S1 surgical levels. 1

• T10 level injection provides at least 4 levels of vertebral coverage in both rostral-caudal directions, ensuring adequate analgesia for the L4-L5 and L5-S1 surgical sites 2
• Bilateral ESP blocks at T10 have been specifically studied and validated for lumbar spine surgery with excellent postoperative pain control 3
• T12 level is an acceptable alternative that also provides effective coverage for lumbosacral procedures 1

Mechanism and Coverage Pattern

The ESP block works through multiple mechanisms that make lower thoracic injection effective for lumbar surgery:

• Local anesthetic spreads to epidural and neural foraminal spaces over 2-5 vertebral levels from the injection site 4
• Additional spread occurs to intercostal spaces over 5-9 levels, contributing to extensive craniocaudal coverage 4
• The block anesthetizes both dorsal and ventral rami of spinal nerves, producing multi-dermatomal sensory blockade 3

Clinical Evidence for Lower Thoracic Approach

Multiple case series and randomized trials support T10-T12 as the injection level for lumbosacral surgery:

• A randomized controlled trial of 60 patients demonstrated that bilateral ESP blocks at T10 significantly prolonged time to first analgesic request (8.0 vs 1.0 hours, p<0.01) and reduced opioid consumption during surgery 3
• A case series of six lumbosacral spine surgeries (including lumbar decompressions and sacral procedures) using T10 or T12 ESP blocks showed minimal postoperative pain and very low opioid requirements in all patients 1
• Fluoroscopic-guided ESP blocks at L3-4 level provided at least 4 levels of coverage, but lower thoracic levels (T10-T12) are preferred as they avoid direct surgical field interference while maintaining adequate spread 2

Technical Considerations for Your Patient

Given the patient's comorbidities (hypothyroidism, hypertension on losartan, borderline renal function):

• ESP block is particularly advantageous as it avoids the hemodynamic instability and urinary retention associated with epidural anesthesia, which is important given the patient's hypertension and renal function 3
• The block does not produce motor blockade or interfere with somatosensory evoked potential monitoring if used intraoperatively 1
• Losartan does not require dose adjustment or discontinuation for ESP block, as the medication's primary concerns relate to pregnancy, hyperkalemia, and renal function rather than regional anesthesia 5

Block Technique

Perform bilateral ESP blocks at T10 (preferred) or T12 level:

• Inject 20 mL of local anesthetic (such as bupivacaine 0.5% or ropivacaine) per side into the fascial plane deep to the erector spinae muscle at the tip of the transverse process 3, 1
• Single-shot technique is effective, though continuous catheters can be placed if extended analgesia is desired 1
• The technique is easily performed under ultrasound guidance with low complication rates 6

Expected Outcomes

Patients receiving ESP blocks at lower thoracic levels for lumbar surgery demonstrate:

• Significantly lower pain scores at rest and with movement in the first 48 hours postoperatively 3
• Reduced intraoperative and postoperative opioid consumption by approximately 40% 3
• Improved quality of recovery scores and shorter post-anesthesia care unit stays 3
• Higher patient satisfaction compared to no block or alternative techniques 3