Effect of Local Anesthetic Dose on Interscalene Block

Effect of Local Anesthetic Dose on Interscalene Block for Shoulder Arthroscopy, Patient Satisfaction and Return of Handgrip Strength

The purpose of this study is to determine if a decrease in the standard volume of local anesthetic used to numb your shoulder area before shoulder arthroscopy will provide adequate anesthesia for the procedure and decrease the amount of time until you are ready for discharge from the hospital.

Traditionally, an interscalene block is done either with nerve stimulator or ultrasound guided using 40-60mL of local anesthetic. The study plans to investigate the difference in hand grip strength post-operatively in patients who will receive interscalene blocks with 40mL versus a lower dose (20mL) of local anesthetic. We suspect the lower dose will achieve adequate surgical anesthesia while creating less motor block and thus, increase patient satisfaction, present fewer complications or adverse affects and decrease time in the recovery room.

Inclusion Criteria:

• Age: 18 - 80 years old
• Surgical time < 2.5 hours
• ASA I, II or III
• Shoulder arthroscopy

Exclusion Criteria:

• Age < 18 or > 80 years old
• Chronic pain patients (on narcotics/opioids > 3 months)
• Open shoulder surgical procedure
• BMI > 40
• Pre-existing neurological condition
• Patient refusal of interscalene block
• Severe respiratory disease or hemidiaphragmatic dysfunction
• Allergy to any local anesthetics
• Planned general anesthesia