Spinal Anesthesia in Outpatient Knee Surgery

Abstract

Spinal anesthesia in day-care surgery is still controver- sial because of the possibility of postdural puncture headache (PDPH). The use of the Sprotte needle with a conical tip that spreads the dural fibers may reduce the incidence of PDPH. The aim of this study was to com- pare the 22-gauge and 25-gauge Sprotte needles with respect to PDPH and postoperative complaints in out- patients undergoing arthroscopy. The rate of spinal an- esthesia failure and the feasibility of unilateral spinal anesthesia when using a low dose of anesthesia was also verified. For this randomized, prospective study, 234 patients undergoing elective arthroscopy were cho- sen. Patients were allocated randomly to have spinal anesthesia with either a 22-gauge or 25-gauge Sprotte needle. Dural puncture was performed with the patient in a lateral flexed decubitus position. After the injection of anesthetic solution (0.5-l .2 mL of 1% bupivacaine in 8% glucose) patients remained in the lateral decubitus position for 30 min. The time to regression of analgesia, time of micturition, and all postoperative complaints were recorded. The most frequent side effect was back- ache (10.2%) with a more frequent incidence in the group using the 22-gauge needle (14.5% and 5.9%, re- spectively). PDPH was recorded in only one patient (0.8%) in the group using the 22-gauge needle. The fail- ure rate was 0.8%. Unilateral anesthesia was achieved in 88% of 213 patients. Our data indicate that the use of spinal block is a suitable technique in the ambulatory setting, with a low rate of unplanned hospital admis- sion. The use of a Sprotte needle does not solve the PDPH problem; however, we confirm that the ex- tremely low incidence and mild character of PDPH when Sprotte needles are used favors spinal anesthesia for outpatient surgery.