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Trunk Blocks — TAP, QL, ESP, PEC
TEXTRegional II · 9 min read
Fascial plane blocks for chest + abdominal wall surgery. Less invasive than neuraxial, broader coverage than local infiltration.
After this lesson you can
4 min read8 sections- Choose TAP, QL, ESP, or PEC for the surgical site.
- Place the probe + identify the fascial plane.
- Anticipate LA volume needed for plane spread.
- Recognize complications + LAST risk.
Why fascial plane blocks emerged
Fascial plane blocks (TAP, QL, ESP, PEC, serratus anterior) gained widespread use 2015-2020 as a middle ground between expensive/risky neuraxial techniques (epidural complications: hematoma, abscess, dural puncture, hypotension from sympathectomy) and local-only infiltration (limited coverage).
Mechanism: LA injected into a fascial plane spreads to nerves traveling within or adjacent to that plane.
Provides multi-dermatomal somatic coverage with simpler technique + safer profile than neuraxial — especially valuable in anticoagulated patients who can't have epidural.
TAP block — transversus abdominis plane
LA volume 15-20 mL per side spreads in this plane and bathes the thoracoabdominal nerves coursing through it.
Coverage: T6/T7-L1 somatic abdominal wall (incisional pain).
DOES NOT cover visceral pain — combine with opioid for major intraperitoneal surgery.
SUBCOSTAL TAP variant: injection more cephalad, covers T6-T10 for upper abdominal incisions.
Excellent for cesarean section, hysterectomy, hernia repair, appendectomy, laparoscopic gallbladder.
QL block — quadratus lumborum
LA placed AROUND the quadratus lumborum muscle in three described approaches: QL1 (anterolateral to QL — pure abdominal wall, similar to posterior TAP), QL2 (posterior to QL — broader spread including potential thoracolumbar fascia and paravertebral spread, T7-L4), QL3 (transmuscular, between QL and psoas — deepest spread, potential lumbar plexus involvement).
QL2 most commonly used.
Broader thoracolumbar coverage than TAP via potential paravertebral spread may include visceral component, making it superior to TAP for hip arthroplasty (covers hip joint capsule afferents) + cesarean.
Larger LA volume (20-30 mL) + ultrasound guidance mandatory.
ESP block — erector spinae plane (the breakthrough)
LA injected DEEP to erector spinae muscle, ANTERIOR to the TRANSVERSE PROCESS at the target level (typically T5 for thoracic, T7-T8 for upper abdominal, L2-L4 for lower abdominal/hip).
LA spreads cranio-caudally in the fascial plane AND penetrates anteriorly via costotransverse foramina to reach the PARAVERTEBRAL SPACE blocks both dorsal AND ventral rami of spinal nerves.
Coverage: 3-6 dermatomes typical, sometimes more.
- thoracic surgery (alternative to thoracic epidural)
- breast surgery
- spine surgery
- abdominal surgery
Variable spread limits absolute reliability — confirm dermatomal coverage before incision if awake.
PEC I + II blocks — breast surgery
Targets the LATERAL + MEDIAL PECTORAL NERVES — covers pec muscle pain in subpectoral implants + tissue expanders.
Targets intercostobrachial + long thoracic + thoracodorsal + lateral cutaneous branches of intercostals covers chest wall + axillary lymph node area.
COMBINE both (PEC1 + PEC2) for total mastectomy + axillary lymph node dissection.
Easier and SAFER alternative to thoracic epidural or paravertebral for breast surgery — no risk of pneumothorax or neuraxial complications.
Serratus anterior plane block
Covers the lateral cutaneous branches of T2-T9 intercostal nerves lateral chest wall + axilla.
- thoracic surgery (alternative to thoracic epidural or paravertebral)
- breast surgery with axillary dissection
- RIB FRACTURES (excellent analgesia + improves respiratory mechanics in elderly with multiple rib fractures)
- chest tube placement
- thoracostomy
Often combined with PEC II for comprehensive chest wall coverage in modified radical mastectomy.
Dermatome map — picking the right block
C4 clavicle, T1 medial arm + axilla, T2 apex of axilla, T4 nipple line, T6 xiphoid, T8 costal margin, T10 umbilicus, T12 pubic symphysis, L1 inguinal, L2 anterior thigh, L4 medial knee + medial calf, S1 sole of foot, S2-S4 perineum.
Always verify coverage before incision if patient is awake; under GA, judge by intraoperative hemodynamics + recovery analgesia.
LA dosing + duration
Duration: bupivacaine 12-18 hr, ropivacaine 8-12 hr.
CONTINUOUS CATHETERS for major surgery: ESP catheter 48-72 hr for thoracotomy; TAP catheter for major abdominal.
Liposomal bupivacaine (Exparel) manufacturer-claimed 72 hr; real-world clinical benefit is debated and often shorter (24-48 hr in independent trials).
LAST recognition + lipid emulsion availability mandatory.
⚠ Common pitfalls
- Treating TAP block as a 'do everything' — it covers T10-L1 only, not visceral pain.
- Calculating max LA dose ignoring bilateral plane blocks — additive risk for LAST.
- ESP at L1-L2 expecting thoracic coverage — anatomic level matters.
- Skipping pre-op ultrasound scan-out — abdominal anatomy varies.
💎 Clinical pearls
- TAP: T10-L1 dermatomes — lower abdominal incision coverage.
- ESP at T5 for thoracotomy/breast; T10 for upper abdominal.
- PEC I + II for breast/axilla surgery (covers pectoral + axillary).
- QL block deeper than TAP — covers visceral pain better but technically harder.
Recap
- TAP: T10-L1 dermatomes — lower abdominal incision coverage.
- ESP at T5 for thoracotomy/breast; T10 for upper abdominal.
- PEC I + II for breast/axilla surgery (covers pectoral + axillary).
- QL block deeper than TAP — covers visceral pain better but technically harder.
Mark each section done to complete the module.