Regional anesthesia for orthopedic procedures: What orthopedic surgeons need to know

Table 1 American Society of Regional Anesthesia guidelines for anticoagulant and antiplatelet drugs

Medication	Minimum time between last dose of medication and neuraxial injection or catheter placement	Minimum time after nerve/neuraxial cathether placement and administration of drug	Minimum time between last dose of drug and cathether removal	Minimum time between neuraxial injection or cathether removal and administration of drug
Anticoagulants for venous thromboembolism prophylaxis
Enoxaparin (Lovenox); prophylaxis, once daily	12 h	≥ 12 h	≥ 12 h	4 h
Enoxaparin (Lovenox); prophylaxis, b.i.d.	12 h	Contraindicated while catheter in place		4 h
Heparin SQ; prophylaxis; low-dose, b.i.d. and t.i.d.	4-6 h	Immediately	4-6 h	Immediately
Heparin SQ; prophylaxis; higher-dose, b.i.d. and t.i.d.	12 h and assessment of coagulation status	Safety of indwelling catheters has not been established for doses > 5000 Units SQ or total daily dose > 15000 Units SQ. Risk/benefit assessment required		Immediately
Dalteparin (Fragmin); prophylaxis, once daily	12 h	≥ 12 h	12 h	4 h
Anticoagulants at therapeutic doses
Heparin IV; full Dose	4-6 h and normal coagulation status	1 h, with close monitoring	4-6 h and normal coagulation status	1 h
Heparin SQ; therapeutic dose	24 h and assessment of coagulation status	Contraindicated while catheter in place		Immediately
Enoxaparin (Lovenox); therapeutic dose	24 h, consider checking anti-factor Xa level	Contraindicated while catheter in place		4 h
Apixaban (Eliquis)	72 h	Contraindicated while catheter in place		6 h
Rivaroxaban (Xarelto)	72 h	Contraindicated while catheter in place		6 h
Warfarin (Coumadin)	5 d and normal INR	Variable instructions regarding management of catheter		Immediately
Anti-platelet medications
NSAID’s	No restrictions, may increase risk of bleeding
Aspirin	No restrictions, may increase risk of bleeding
Plavix	5-7 d	24 h postoperatively; catheter may be maintained for 1-2 d due to delayed antiplatelet effect		Immediately if no loading dose given
Ticlodipine (Ticlid)	10 days	24 h postoperatively; catheter may be maintained for 1-2 d due to delayed antiplatelet effect		Immediately if no loading dose given
Ticagrelor (Brillinta)	5-7 d	Contraindicated while catheter in place		Immediately if no loading dose given

NSAID: Non-steroidal anti-inflammatory drug.

Table 2 Summary of upper extremity peripheral nerve blocks

Block	Clinical application	Nerves blocked	Anatomical landmarks	Advantages	Disadvantages	Complications
Interscalene nerve block	Surgeries involving the shoulder, proximal aspect of humerus and the distal aspect of the clavicle	(1) Brachial plexus:C5 to C7; and (2) Cervical plexus: Supraclavicular nerve (C3 and C4)	LA injected between anterior and middle scalene muscles lateral to carotid artery and internal jugular vein	(1) Easy to perform; and (2) Comfortable for the patient	(1) Hemidiaphragmatic paralysis leading to respiratory compromise in patients with severe COPD; and (2) Not sufficient for elbow, forearm or hand surgeries	(1) Phrenic nerve palsy (100%); (2) Horner syndrome; and (3) Hoarseness
Supraclavicular nerve block	Surgery of the arm, elbow, forearm and hand. Extension into the interscalene area can cover shoulder procedures	C5-T1	LA injected above the clavicle between anterior and middle scalene muscles at the level of the first rib, where the subclavian artery crosses over it	(1) Fast onset; (2) Easier to perform; and (3) Comfortable for the patient	Relatively higher incidence of pneumothorax	(1) Pneumothorax; (2) Phrenic nerve palsy; and (3) Hoarseness
Infraclavicular nerve block	Surgery of the arm, elbow, forearm and hand	C5-T1	LA injected around the axillary artery below the clavicle, medial to coracoid process	Good choice for catheter placement	(1) Deeper block to perform; and (2) Greater discomfort during block placement	Pneumothorax (relatively low incidence)
Axillary nerve block	Surgery of the elbow, forearm and hand	Median nerve, ulnar nerve, radial nerve, and musculocutaneous nerve	LA injected around the axillary artery at the medial aspect of proximal arm	(1) Easy to perform; and (2) Low complication rate	(1) Often spares the musculocutaneous nerve; and (2) Requires arm abduction	(1) Hematoma formation; and (2) Intravascular injection

COPD: Chronic obstructive pulmonary disease.

Table 3 Summary of lower extremity peripheral nerve blocks

Block	Clinical application	Nerves blocked	Anatomical landmarks	Advantages	Disadvantages	Complications
Femoral nerve(Femoral nerve block)	Surgeries involving anterior aspect of the thigh and medial aspect of the leg below the knee	Femoral nerve	Inguinal crease; located lateral to femoral artery	(1) Broad coverage; and (2) Easily identifiable landmarks	Causes quadriceps weakness which may lead to falls	(1) LE weakness and falls; (2) Bleeding; (3) Infection; and (4) Nerve damage
Femoral nerve (Fascia Iliaca block)	Surgeries involving anterior aspect of the thigh and medial aspect of the leg below the knee	(1) Femoral nerve; and (2) Lateral femoral cutaneous nerve of the thigh	Inguinal crease, LA injected under fascia iliaca	(1) Easily identifiable landmarks; and (2) Assist in optimal patient positioning for spinal anesthesia	(1) Causes quadriceps weakness which may lead to falls; and (2) Large volume of local anesthetic required	(1) LE weakness and falls; (2) Bleeding; (3) Infection; and (4) Nerve damage
Sciatic nerve (Anterior, transgluteal, and subgluteal approaches)	Surgeries involving foot, ankle, and posterior knee	Sciatic nerve	Variable, based on injection site	(1) Broad lower extremity coverage; and (2) Easilyidentifiable landmarks	Motor blockade	(1) Bleeding; (2) Infection; and (3) Nerve damage, persistent foot drop and heel ulcers
Sciatic nerve (Popliteal Block)	Surgeries involving foot, ankle, posterior knee	Sciatic nerve	Popliteal fossa, located cephalad to the knee near popliteal artery	(1) Broad lower extremity coverage; and (2) Easilyidentifiable landmarks	Motor blockade	(1) Bleeding; (2) Infection; and (3) Nerve damage, persistent foot drop and heel ulcers
Saphenous nerve (Femoral triangle, medial femoral condyle, tibial tuberosity approaches)	Surgeries involving medial aspect of knee, foot, and ankle	Saphenous nerve	Variable, based on injection site	Motor-sparing	Does not provide anesthesia and analgesia to the posterior capsule of knee	(1) Bleeding; (2) Infection; and (3) Nerve damage - Potential lower extremity weakness at high doses
Saphenous nerve (Adductor Canal block)	Surgeries involving medial aspect of knee, foot, and ankle	(1) Saphenous nerve; and (2) Nerve to vastus medialis (branch of femoral nerve)	Medial thigh, located deep to the sartorius muscle, adjacent to the femoral artery and vein.	Motor-sparing	(1) Does not provide anesthesia and analgesia to the posterior capsule of knee; and (2) Compared to femoral nerve block, it is less efficacious for analgesia after ACL reconstruction surgery	(1) Bleeding; (2) Infection; (3) Nerve damage; and (4) Potential lower extremity weakness at high doses
iPACK	Surgeries involving the posterior knee capsule	Articular branches of the tibial, common peroneal, and obturator nerve to the posterior aspect of the knee	Popliteal crease, located cephalad to femoral condyles	Motor-sparing, increased posterior knee coverage	Coverage only to posterior knee; useful as an adjunct to alternative blocks	Inadvertent motor block due to local anesthetic spread to sciatic nerve branches
Ankle	Foot surgery	Saphenous, sural, posterior tibial, superficial peroneal, and deep peroneal nerves	Ankle and foot bony landmarks	Injection based on surface landmarks, no requirement for ultrasound	Limited efficacy for surgery proximal to the foot, potential higher failure rate due to blind technique	(1) Bleeding; (2) Infection; and (3) Nerve damage
Lumbar plexus	Hip surgery	Lumbar plexus, providing blockade to femoral, obturator, and lateral femoral cutaneous nerves	Lateral to lumbar spine, located cephalad to iliac crest	Coverage of multiple nerves with a single block	High potential for complications and block failure, technically challenging block to perform	(1) Bleeding and hematoma; (2) Infection; (3) Nerve damage; (4) Epidural spread resulting in high neuraxial anesthesia; (5) Hypotension, and (6) LAST

ACL: anterior cruciate ligament; LAST: local anesthetic systemic toxicity.

Table 4 Clinical presentation and management of local anesthetic systemic toxicity

Local anesthetic systemic toxicity (LAST)
Clinical presentation of LAST
1 Dizziness, drowsiness, tinnitus, perioral numbness
2 Muscle twitching and tremors
3 Seizures
4 CNS depression, coma
5 Hypertension, tachycardia
6 Myocardial depression, ventricular arrhythmias, conduction delays
7 EKG changes: Prolonged PR, QRS; T-wave changes
8 Cardiovascular collapse
Management of LAST
1 Call for help
2 Call for LAST rescue kit
3 Consider early lipid emulsion administration
(1) Under 70 kg: Bolus 1.5 mL/kg over 2-3 min, Infuse 0.25 mL/kg/min. Repeat bolus or double the infusion rate if the patient remains unstable
(2) Over 70 kg: Bolus approximately 100 mL over 2-3 min, infuse approximately 250 mL over 15-20 min. Repeat bolus or double the infusion rate if the patient remains unstable
(3) If the patient is stable, continue lipid emulsion ≥ 15 min after hemodynamic stability. Maximum lipid dose: 12 mL/kg
4 Seizure
(1) Airway management
(2) Benzodiazepine
(3) Consider low dose propofol
5 Arrhythmia or cardiovascular Instability
(1) Epinephrine: Administered at lower dose than ACLS dosing, start with ≤ 1 mcg/kg
(2) Avoid local anesthetics, beta-blockers, vasopressin, calcium channel blockers
(3) Consider alerting cardiopulmonary bypass team
6 Close monitoring
Once stable, continue close monitoring: 2 h after seizure, 4-6 h after cardiovascular instability, and as clinically appropriate after cardiac arrest

EKG: Electrocardiogram; CNS: Central nervous system.