Transversus Abdominis Plane (TAP) Block

Quick Answer

The TAP block provides analgesia to the anterior abdominal wall (T7-L1 dermatomes) by depositing local anaesthetic in the transversus abdominis plane between internal oblique and transversus abdominis muscles where the thoracolumbar nerves (T7-L1) run. Indications: Analgesia for midline and lateral abdominal incisions (open/laparoscopic cholecystectomy, appendicectomy, hernia repair, caesarean section, hysterectomy, prostatectomy); opioid-sparing effect (30-50% reduction in postoperative opioid consumption); effective for somatic pain (not visceral). Technique: Ultrasound-guided lateral (Petit triangle/petit approach) or subcostal approach; 20-30 mL 0.25-0.375% ropivacaine or 0.25-0.5% bupivacaine per side; catheter techniques for continuous infusion. Duration: Single injection 12-24 hours; continuous infusion extends to 48-72 hours. Complications: Intraperitoneal injection (rare, bowel injury if needle too deep), vascular injury (epigastric vessels), local anaesthetic toxicity (especially bilateral blocks with large volumes), infection, femoral nerve palsy (lateral cutaneous branch of iliohypogastric/ilioinguinal if needle too low), liver laceration (subcostal approach). Contraindications: Infection at site, coagulopathy, patient refusal, pre-existing abdominal wall nerve injury. Evidence: Meta-analyses show significant reduction in opioid consumption and pain scores for first 24 hours; no effect on chronic pain development or long-term outcomes. Subcostal TAP: Targets T7-T9 nerves for upper abdominal surgery; lateral TAP targets T10-L1 for lower abdominal surgery; quadratus lumborum block (QLB) provides longer duration and visceral analgesia for more extensive procedures. Indigenous patients: No specific contraindications; higher obesity rates may increase technical difficulty but ultrasound guidance standardizes approach. [1-10]