True resistance to local anesthetics, a case report

Background: We report a case with apparent resistance to local anesthetics. While regional anesthetics failure are often attributed to technical failure, the clinical presentation and medical history of this patient suggests a true resistance to local anesthetics. Case report: A 28 years old man was scheduled for elective orthopedic surgery for right sided tibial bone fracture, and decision of spinal anesthesia was made. There was a questionable history of multiple prior episodes of local anesthetic unresponsiveness (Interscalan block, local infiltration for lipoma resection and dental surgery). Spinal anesthesia was performed and sensory or motor blockade was not obtained despite any evidence of technical problems. The surgical procedure performed under general anesthesia and skin analgesia (local infiltration of lidocaine 2% and bupivacaine 0.5% to forearm), did not achieve, the day after surgery. Conclusion: While the failure rate of spinal anesthesia has been shown range from 4 to 13% and is often attributed to technical failure, this particular case showed a true resistance to local anesthetics.