Regional Block Selection by Surgery

Regional Anesthesia · 8 min read

Picking the right regional block for the right surgery is half technique, half cognitive map. This lecture walks through the most common surgeries and the matching block — and the failure modes when you pick wrong.

Shoulder + upper arm — interscalene

INTERSCALENE BLOCK: targets superior + middle trunks of brachial plexus (C5-C7). Coverage: shoulder + lateral upper arm + clavicle. ALWAYS misses ulnar (C8-T1) and inferior trunk — supplement axillary block for hand surgery. Volume: 15-20 mL of 0.375-0.5% ropivacaine. WARN PATIENT about phrenic nerve block (100% incidence — ipsilateral hemidiaphragm paresis, ~25% FEV1 reduction). CONTRAINDICATED in severe COPD, contralateral phrenic palsy, severe pulmonary hypertension. Ultrasound landmark: between anterior + middle scalene muscles at C6 level.

Hand + forearm — supraclavicular or axillary

SUPRACLAVICULAR BLOCK: at the divisions level (between trunks + cords). Coverage: entire arm below shoulder. Advantage: fast, complete block. RISKS: pneumothorax (~0.5%), phrenic block (~50%), Horner syndrome. Volume: 20-30 mL. AXILLARY BLOCK: at terminal branches (median, ulnar, radial, musculocutaneous) — safest, no pneumothorax, no phrenic. Coverage: forearm + hand. Misses musculocutaneous (block separately if forearm surgery extending to radial side). Volume: 30-40 mL distributed around artery.

Lower extremity — adductor canal, popliteal sciatic, lumbar plexus

ADDUCTOR CANAL BLOCK (saphenous nerve from femoral): for KNEE surgery (TKA, ACL, knee scope). Spares quadriceps motor function (vs femoral nerve block) — allows early ambulation + reduces fall risk. Volume: 15-20 mL. Combine with iPACK (popliteal-plexus posterior knee infiltration) for posterior knee analgesia. POPLITEAL SCIATIC: for ankle/foot surgery + Achilles repair. Volume: 25-30 mL. Combine with saphenous block (medial ankle territory). LUMBAR PLEXUS POSTERIOR (psoas compartment): for hip surgery, femur surgery — broader but more complications. Modern preference: adductor canal + iPACK + LFCN for hip arthroplasty.

Abdominal wall — TAP, QL, ESP

TAP BLOCK (transversus abdominis plane): SOMATIC analgesia T6-L1 to abdominal wall. Bilateral for midline incision (e.g., laparotomy, C-section). Subcostal for upper abdomen. NOT visceral — pair with multimodal analgesia. Volume: 20 mL each side. QUADRATUS LUMBORUM (QL): broader spread, paravertebral component → some visceral analgesia. Better for c-section, total abdominal. ERECTOR SPINAE PLANE (ESP): dermatomal coverage T2-L2 depending on level — versatile, simpler than thoracic epidural for many cases.

Thorax — paravertebral, ESP, intercostal

THORACIC EPIDURAL: gold standard for thoracotomy. Covers T2-T10. Hypotension common. Anticoagulation contraindications strict. PARAVERTEBRAL BLOCK (PVB): equivalent analgesia to epidural with less hypotension + fewer contraindications — newer preference. ESP at T5-T6: increasingly used for thoracotomy + breast surgery as easier alternative. Bilateral ESP for sternotomy. INTERCOSTAL BLOCKS: for rib fractures, chest tube site analgesia — multiple injections, short duration.

Selection summary by surgery

Shoulder/clavicle → Interscalene. Hand/forearm → Supraclavicular or Axillary. Knee TKA → Adductor canal + iPACK. Hip arthroplasty → Adductor canal + LFCN + lumbar plexus considered. Ankle/foot → Popliteal sciatic + saphenous. Abdomen → TAP or QL or ESP (not all three). Thoracotomy → Thoracic epidural OR paravertebral OR ESP. C-section → spinal anesthesia primarily; bilateral TAP for postop. Cesarean with general → bilateral TAP + IV opioids.

Don't forget: max LA dose + ASRA timing

MAX TOTAL LOCAL ANESTHETIC dose: ropivacaine 3 mg/kg, bupivacaine 2.5 mg/kg, lidocaine 4.5 mg/kg (with epi 7 mg/kg). For bilateral or multi-block techniques, sum the doses. ASRA neuraxial anticoagulation guidelines for spinal/epidural: prophylactic LMWH 12 h, therapeutic LMWH 24 h, DOAC 24-72 h depending on agent + renal function. Always check before sticking.

References

· Hadzic Regional Anesthesia and Pain Medicine 2e
· ASRA Anticoagulation Guidelines 2018
· Reg Anesth Pain Med — Block Selection Reviews