Possible Subdural Block during Interscalene Brachial Plexus Block: A Case Report.

The interscalene block technique is widely used for a variety of procedures on the upper extremities. In general, this technique is safe and effective but is not without hazards. A case of subdural block resulting from an interscalene block is presented. In a 60-year-old female patient with carpal tunnel syndrome, sudden bradycardia, unconsciousness and respiratory arrest developed within several minutes after performing the block. At the end of the postinjectional third hour, she regained full consciousness, spontaneous breathing and full sensorial functions, except for profound anesthesia in the right arm. Within 6.5 hours of injection, right arm strength and sensation returned to normal; however, analgesia remained until the postinjectional ninth hour.