Comparison between spinal anaesthesia and sciatic-femoral block for arthroscopic knee surgery

We compared spinal anesthesia and sciatic-femoral block for arthroscopic knee surgery in terms of hemodynamic changes, intraoperative anesthesia, postoperative analgesia, postoperative motor block and bladder function, side effects, and patient satisfaction.

Thirty-two patients were randomised into 2 groups: Group B (sciatic-femoral block with mepivacaine 1% 15 + 25 mL, 120 mm/35 mm 22-gauge needles and ElectroNerve Stimulator) and Group S (unilateral spinal anesthesia with 7 mg of hyperbaric bupivacaine 0.5% and 25-gauge Sprotte needle in L2-L3 space). We recorded pain, together with hemodynamic parameters (baseline, 5, 10, 15, 30 min), utilising Numerical Rating Scale (NRS) during the tourniquet application and during the surgical procedures, anesthesia quality, orthopedic evaluation for intraoperative liberty of knee movement. During the postoperative period we recorded at 2, 4 and 6 h: postoperative analgesia, motor block, first urine output, side effects, first requirement for analgesic drug, patient satisfaction and costs.

The only significant differences between the 2 groups (P<0.05) were the heart rate changes at 10, 15, 30 min with an increase in Group B and a decrease in Group S, and the first urine output at 200+/-69 min in Group B versus 269+/-66 min in Group S.

In conclusion the sciatic-femoral nerve block is a valid alternative to spinal anesthesia for arthroscopic knee surgery, leading to a faster discharging from the hospital.