1. Lower Extremity Regional Anesthesia in the Orthopedic Patient
David Freeze

2. Anatomy of Peripheral Nerves
Neuron is responsible for conduction of nerve impulses
Longest cells in the body

3. Common Medications Tetracaine (Class: Esters) -
Bupivacaine (Class: amides)
most common
Ropivacaine (Class: amides)
Cocaine is a natural anesthetic

4. Local Anesthetic Short Acting (45-90 minutes)
2-chloroprocaine
Intermediate Acting ( minutes)
Lidocaine, mepivacaine
Long Acting (4-18 hours)
Bupivacaine, ropivacaine, levobupivacaine)

5. What Impacts duration of a block
Lipid solubility
Degree of vascularity of the tissue
Presence of vasoconstrictors that prevent vascular uptake – epinephrine
Greater lipid solubility increases the affinity of the drug causing greater potency and duration of action

6. Smaller Nerve fibers are more susceptible to the effects of local anesthesia
Myelinated fibers are more easily blocked than unmyelinated because the local anesthesia pools near axonal membrane

7. Adverse Effects Systemic Toxicity Symptoms Cardiac Toxicity
Mild: Lightheadedness, dizziness, visual or auditory disturbances, disorientation, drowsiness, metallic taste
Severe: shivering, muscular twitching tremors, hypotension, sinus brady, cardiac collapse, cardiac dysrhythmias, resp. dep.

8. Avoid Adverse Effects
Toxicity is typically avoided by appropriate selection of medication, dose, and concentration.
Technique is also critical
Slow incremental injections with frequent aspirations

9. Lower Extremity Blocks
Common Blocks:
Adductor Canal
Spinal
Sciatic
Femoral Nerve

10. Spinal Neuraxial Block
Space in the cerebrospinal fluid that surrounds the spinal cord
Bupivacaine 3-4 hrs
Tetracaine 5-6 hrs

11. Femoral Nerve Block Insertion at Groin
Femoral Nerve innervates L2 to L4
Covers anterior, medial, and interior but spares lateral and posterior
Greater Pain control
Increased risk of falls

12. Adductor Canal Insertion at Mid thigh
Preserves most of the motor function of the quadriceps
Reduces risk of falls

13. Sciatic Nerve Insertion anterior or gluteal
Ideal for Lower Leg Surgery
BKA
Achilles Tendon Repair
Tibial or Fibula Surgery
Foot

14. References
American Society of Regional Anesthesia and Pain Medicine. (2016). Regional anesthesia for surgery. Retrieved from New York School of Regional Anesthesia (NYSORA). (2016). Regional anesthesia. Retrieved from