Unilateral Spinal Anesthesia Research Articles

Unilateral spinal anaesthesia: gadget or tool?

The results of different studies investigating the use of unilateral spinal anaesthesia are confusing and partly inconsistent. Some authors doubt whether it is possible to create a strictly unilateral block (i.e. motor, sensory and sympathetic) at all, while others claim that such a procedure is standard, especially for ambulatory anaesthesia. This review considers those factors which are relevant, plausible and proven.

Does speed of intrathecal injection affect the distribution of 0.5% hyperbaric bupivacaine?

We have evaluated the influence of speed of intrathecal injection on lateral distribution of 0.5% hyperbaric bupivacaine. We studied 60 patients undergoing lower limb surgery who were placed in the lateral position with the operative side in the dependent position. After dural puncture (25-gauge Whitacre spinal needle), the needle aperture was turned towards the dependent side and 0.5% hyperbaric bupivacaine 8 mg was injected randomly at a rate of 0.02 ml s-1 (group slow, n = 30) or 0.25 ml s-1 (group fast, n = 30). Lateral position was maintained for 15 min while a blinded observer recorded loss of pinprick sensation and degree of motor block on both surgical and non-surgical sides. There were no differences between the groups. Forty-five minutes after patients were turned to the supine position, spinal anaesthesia was unilateral in 17 patients in group slow (56%) and in 13 patients in group fast (43%). We conclude that using extremely low speeds for intrathecal injection were not clinically advantageous in obtaining unilateral spinal anaesthesia.

Cardiovascular effects of two different regional anaesthetic techniques for unilateral leg surgery

Cardiovascular function was assessed in 20 ASA I-II patients, scheduled for elective orthopaedic surgery with tourniquet in order to compare the haemodynamic changes induced by unilateral spinal anaesthesia and combined sciatico-femoral nerve block. After baseline measurement of cardiovascular parameters, patients were randomized to receive unilateral spinal anaesthesia or combined sciatico-femoral nerve block. Spinal anaesthesia was obtained by 8 mg of hyperbaric bupivacaine 0.5% slowly injected (speed=0.02 ml s[-1]) through a 25-G Whitacre spinal needle with the bevel orientated towards the dependent side and patients lying on their operated side for 15 min (group S, n=10). Combined sciatico-femoral nerve block was obtained by 7 mg kg(-1) of mepivacaine 2% (group NB, n=10). Haemodynamic variables were recorded 5, 10, 15, and 30 min after anaesthetic injection before surgery was started. Anthropometric data, duration of surgery and acceptability of anaesthetic techniques were similar in the 2 groups. In 8 patients of group S, spinal block was restricted to the operated side (pinprick test and Bromage scale), while the other 2 patients developed bilateral spinal block after being turned supine. NB patients showed no haemodynamic changes during the study, whereas patients in group S showed a small but significant decrease of mean arterial blood pressure (P<0.002 vs baseline and P<0.04 vs NB), cardiac index (P<0.01 vs baseline and P<0.01 vs NB), and stroke volume index (P<0.01 vs baseline and P<0.01 vs NB). Both sciatico-femoral and unilateral spinal blockade provide adequate anaesthesia for unilateral leg surgery with tourniquet. The former technique affects cardiovascular performance less than the latter one.

A transient neurological deficit following intrathecal injection of 1% hyperbaric bupivacaine for unilateral spinal anaesthesia

A transient neurological deficit following intrathecal injection of 1% hyperbaric bupivacaine for unilateral spinal anaesthesia

Influence of Duration of Lateral Decubitus on the Spread of Hyperbaric Tetracaine During Spinal Anesthesia

Comment: The addition of a 0.2 mg of epinephrine to 12 mg of tetracaine in 2.5 mL 10% dextrose and failure of randomization to prevent significant differences in height and weight between the four groups should not detract from the important conclusions of this study. The longer the duration of lateral decubitus position is maintained, the longer the duration of sensory block. However, after subtracting the duration of time spent in the lateral decubitus position from the duration of sensory and motor blocks, there was no gain in terms of prolonged surgical time. Many clinicians use hyperbaric tetracaine in a lateral decubitus position for 1 to 5 min to obtain unilateral spinal anesthesia for patients undergoing unilateral lower limb surgery, to provide more profound and longer duration sensory block of the affected extremity, and to minimize the sympathetic block obtained. Such clinicians will be reassured that there are no obvious clinical advantages to prolonging the lateral decubitus position for 12 or 18 min, as demonstrated by this study.

Spinal Anesthesia in Outpatient Knee Surgery

Spinal anesthesia in day-care surgery is still controversial 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 compare the 22-gauge and 25-gauge Sprotte needles with respect to PDPH and postoperative complaints in out-patients undergoing arthroscopy. The rate of spinal anesthesia 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 chosen. 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 (0.5-1.2 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 backache (10.2%) with a more frequent incidence in the group using the 22-gauge needle (14.5% and 5.9%, respectively). PDPH was recorded in only one patient (0.8%) in the group using the 22-gauge needle. The failure 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 admission.(ABSTRACT TRUNCATED AT 250 WORDS)

Unilateral spinal anaesthesia and prolonged femoral nerve block

Unilateral spinal anaesthesia and prolonged femoral nerve block

Unilateral spinal anesthesia for surgical reduction of hip fractures

1. 1. One hundred sixteen consecutive operations for fractured hip were done under a method of unilateral spinal anesthesia. The details of the method are given. 2. 2. Seventy-two per cent of the patients were poor operative risks and 83 per cent were more than sixty years old. There were no anesthetic deaths. 3. 3. Unilateral spinal anesthesia may be used for hip surgery in old poor risk patients without increasing the hazard of operation.