Spinal, epidural or propofol anaesthesia for out-patient knee arthroscopy?

We have compared three different methods of anaesthesia for out-patient knee arthroscopy in terms of perioperative conditions, postoperative pain, time taken and economy.

91 ASA I-II patients scheduled for elective knee arthroscopy were included. After premedication with diazepam 10 mg and naproxene 500 mg orally, they were randomly assigned into one of three groups: Group S (n=32) received spinal anaesthesia with lidocaine 50 mg/ml 1.5-2 ml in 7.5% glucose through a 27-G Quincke needle, Group E (n=29) received epidural anaesthesia with mepivacaine 20 mg/ml and epinephrine 5 microg/ml, 15-20 ml, and Group P (n=30) received propofol anaesthesia with a bolus induction of 2 mg/kg followed by infusion.

The time from start of anaesthesia until start of operation was significantly less in Group P than in the two other Groups: 7.4+/-5.4 min as compared to 23.0+/-4.8 min in Group S and 31.0+/-9.1 min in Group E (mean+/-SD, P<0.05). After end of surgery, the duration of the postoperative regional block was 75+/-28 min in Group S and 125+/-79 min in Group E (P<0.05). In Group S and Group E the postoperative pain was significantly less than in Group P at admission to the recovery unit and 60, 120 and 180 min later (P<0.05). The overall incidence of post-operative nausea or vomiting was less than 5% with no differences between the groups. One patient in Group E had block failure and one patient in Group S had a post-spinal headache. The perioperative costs of drugs and disposables were highest in Group P (30 USD) and lowest in Group S (6.5 USD).

Propofol anaesthesia results in the shortest stay in the operation theatre but a higher degree of postoperative pain and a higher cost of drugs and disposables.