Inclusion Criteria:  ASA status I, II, and III patients, aged 60-75 y, both male and female, undergoing inguinal hernia repair surgery.  Exclusion Criteria:  morbid obesity (BMI > 40), spine metastatic tumor, allergy to an amide LA, or magnesium sulfate, heart block, renal, or liver dysfunction, substance abuse disorder, chronic opioid use, or electrolyte disturbance, administration of any sedative, preexisting mental illness, psychological or emotional problems.