The optimal dose of local anaesthetic in the orthogonal two-needle technique. Extent of sensory block after the injection of 20, 30 and 40 mL of anaesthetic solution.

Ninety patients undergoing scheduled upper limb orthopaedic surgery were studied to determine the optimal anaesthetic dose using the 'orthogonal two-needle technique'. The patients were randomly assigned to one of three groups to receive one of three different volumes (20, 30 and 40 mL) (n = 30) of anaesthetic solution (a mixture of equal parts of 0.5% bupivacaine with adrenaline 1:200,000 and 2% lignocaine). A significant correlation was found between the volume injected and the anaesthetic spread for all tested areas. A better analgesic spread to all the major branches of the plexus was obtained when increased volumes of anaesthetic solution were injected. The comparisons between the 20 mL group and the other two groups are significant in all the tested areas, as well as the comparisons between 30 and 40 mL groups in the areas innervated by radial and musculocutaneous nerves. Only the area innervated by the axillary nerve showed a weaker volume-analgesia relation, confirming the elusiveness of this area to anaesthesia in the axillary approaches. The improved results observed using greater amounts of anaesthetic solution might result from a higher intrasheath pressure with disruption of sheath septa, or from a greater availability of drug for all the terminal branches of brachial plexus, or both.

Postspinal headache in Taylor's approach: a comparison between 21- and 25-gauge needles in orthopaedic patients.

A randomized study was carried out on 160 patients aged 30-60 years with the aim of finding a method of preventing postdural puncture headache (PDPH). In Taylor's lumbosacral approach to the subarachnoid space, two different needle sizes were used (21-gauge versus 25-gauge) for injecting the anaesthetic solution. Our results show an overall incidence of PDPH in nearly 8% of patients, with no significant difference related to the size of the needle employed. Patients with PDPH showed mild symptoms which disappeared in a short time and none needed epidural blood patching. The possibility of using larger needles, facilitating the execution of the block without increasing PDPH incidence, renders this technique particularly attractive in patients where the midline approach is not feasible, or when pencil-point needles are not available.

Effect of injection speed on anaesthetic spread during axillary block using the orthogonal two-needle technique.

One hundred patients undergoing scheduled upper limb orthopaedic surgery were studied to determine if the speed of injection of the local anaesthetic solution could modify the extent and depth of anaesthesia with the axillary approach to the brachial plexus. The blocks were performed using the 'orthogonal two-needle technique' in which two needles are positioned on the upper and on the lower aspect of the axillary artery, orthogonal to the neurovascular bundle and directed towards the fascial compartment containing the radial nerve. The patients were randomly assigned to one of three groups to receive one of three injection rates (10, 20 and 30 s) (n = 30). In consequence to the results obtained in these patients, a further group of 10 patients was a posteriori added for whom the injection time for each single shot of anaesthetic solution was increased to 1 min. In each group the same mixture and volume of anaesthetic solution (a 30 mL mixture of equal parts of 0.5% bupivacaine with adrenaline 1:200,000 and 2% lignocaine) was injected in two separate boluses of 15 mL each through the two positioned needles. A significant association was found between the injection rate and the anaesthetic spread for all tested areas with the exception of the regions supplied by the median nerve. A greater speed of injection was associated with less anaesthetic spread and more frequent block failure. A clear association between the anaesthetic spread to all branches of the brachial plexus and a slower injection rate of the local anaesthetic was found.

The orthogonal two-needle technique: a new axillary approach to the brachial plexus.

Ninety-eight patients scheduled for elbow, forearm, wrist or hand surgery were allocated randomly to one of two different techniques of brachial plexus block, both using the axillary approach. The blocks were all performed at the level of the insertion of the lateral margin of the pectoralis major muscle on the humerus. The same mixture and volume of anaesthetic solution (30 mL of a mixture of equal parts of 0.5% bupivacaine with adrenaline 1:200 000 and 2% lignocaine) was injected through two needles positioned above and below the axillary artery, in the fascial compartments containing the median and ulnar nerves, respectively. Confirmation of correct needle placement was obtained by elicitation of paraesthesias. In one group of patients (n = 40) the needles were inserted parallel to the axillary artery pathway and the anaesthetic solution was injected toward the apex of the axilla. In a second group (n = 58) the needles were inserted orthogonally with respect to the neurovascular bundle pathway, aimed towards the posterior fascial compartment containing the radial nerve. Using the second technique, all the terminal branches of the brachial plexus were more frequently involved in the block, including the distribution of the musculocutaneous nerve. It seems likely that the inclination of the needles causes a preferential spread of the anaesthetic solution which follows the direction of the needle shaft.

Preferential channelling of anaesthetic solution injected within the perivascular axillary sheath.

Preferential channelling of anaesthetic solution injected into the perivascular axillary sheath was investigated in 40 patients undergoing elective orthopaedic upper-limb surgery. Three needles, with different approaches and inclinations, were inserted near the three main terminal branches of the brachial plexus using an axillary approach. Separate boluses of anaesthetic solution (12 ml of a mixture of equal parts of 0.5% bupivacaine with 1:200,000 adrenaline and 2% lignocaine) were injected in random order through each needle, and back flow through the other two needles was noted. Back flow was observed, mainly in the needle nearest to the radial nerve during injection of the anaesthetic solution in the superior and inferior aspects of the brachial artery, and in the needle close to the ulnar nerve when the injection was performed posterior to the artery, near the radial nerve. These results could be related to the trapping of anaesthetic solution in unconnected compartments and to the slope of the needle injecting the anaesthetic solution which spreads preferentially along a gradient following the needle shaft direction.

How many interscalenic blocks are there? A comparison between the lateral and posterior approach.

This study compares the areas of analgesia obtained with the lateral and posterior approaches to the interscalene space after injection of equal volumes of anaesthetic solution (40 ml of a mixture of 0.5% bupivacaine with adrenaline 1:200,000 and 2% lignocaine in equal parts). There was a significant difference in the distribution of the areas of analgesia between the two approaches. With the posterior approach, the region supplied by the radial, medial and ulnar nerves and the post-axial border of the upper limb were more frequently involved, whilst with the lateral approach the area of analgesia was usually confined to the regions supplied by the most caudal roots of the cervical plexus and the upper trunk of the brachial plexus (pre-axial border of the upper limb). On these grounds it appears that two different types of interscalene block are possible.

[The external jugular vein course as surface landmark in subclavian perivascular block]. / Il decorso della vena giugulare esterna quale punto di repere di superficie nel blocco perivascolare succlavio.

A study of 88 orthopaedic patients undergoing upper limb surgery, was carried out using the external jugular vein as surface landmark of the brachial plexus in subclavian perivascular technique. A significant statistical relationship was found between the insertion point of the needle, relatively to the external jugular vein course, and the block outcome. The best results were observed when the needle was inserted on the postero-lateral side of the vein or when the insertion point coincided with the vein course. Worse results were obtained by foreward insertion. So the external jugular vein could be used as surface landmark to improve the plexus localization in the subclavian perivascular technique of brachial plexus anaesthesia.

[How many interscalene blocks are there? Reflections on 109 cases studied with various techniques]. / Quanti sono i blocchi interscalenici? Riflessioni su 109 casi eseguiti con tecniche diverse.

The effects of interscalene block were studied on 109 patients undergoing upper extremity elective orthopaedic surgery. Blocks were performed in a non-randomized manner with three different techniques, the site where anaesthetic solution was injected being the main distinguishing mark. The anaesthetic solution was injected into the interscalenic compartment both in the case of patients where classic technique had been carried out and in the group where the nerve stimulator had been used. In the "double needle" technique group, on the contrary, the anaesthetic solution was injected close to the vertebral column. The spread of analgesia involves the caudal portion of the cervical plexus and the cranial portion of the brachial plexus, but with the cervical plexus is almost certain to be involved, the brachial is not. Block outcome was related to the surgical procedure (surgery or orthopaedic manipulation), the site of surgery, paraesthesia elicitation, prolonged surgery and height, weight, age and sex of patients. Results also different according to the technique used. When the anaesthetic solution was injected close to the vertebral column analgesic cover was more widespread and lesser amounts of anaesthetic needed. When the block was performed within the interscalenic compartment, the analgesic cover was usually restricted to the area supplied by the primary superior trunk of the brachial plexus. The different results were explained by the presence of fibrous sheaths within the interscalenic compartment limiting spread of the anaesthetic, which are absent close to the vertebral column. Therefore two types of interscalene block were postulated: an intrascalene or troncular block within the interscalenic compartment and a radicular or paravertebral block close the vertebral column.

A new approach to sciatic nerve block in the gluteal region.

Two personal techniques of sciatic nerve block in the gluteal region were compared in a retrospective study. The study was carried out on 224 patients undergoing elective orthopaedic lower-limb surgery. The block was performed in 107 subjects with a modified Labat's technique, prolonging his line downwards to meet the surface projection of the sciatic nerve, according to Ellis and McLarry. In 117 patients the needle was inserted at the intersection of the hiatus-trochanteric line with a straight line joining the midpoint of the thigh with the posterior-superior iliac spine. The use of these landmarks improved paraesthesia elicitation and increased absolute success rate (66%). A dramatic drop in intra-operative supplemental analgesic and hypnotic needs was observed in these patients. Failure occurred in about 10% with both techniques, whilst side-effects were of minor importance. These results suggest that the new landmarks provide a more precise anatomo-clinical location of the sciatic nerve.

Fentanyl and bupivacaine mixture for extradural blockade in orthopaedic surgery: effects on haemodynamic responses and pain related to the use of thigh tourniquet.

Analgesic and haemodynamic changes due to tourniquet application were investigated in a prospective double-blind study on orthopaedic patients submitted to extradural lumbar blockade with a bupivacaine and fentanyl mixture. The study was carried out in 161 healthy patients undergoing limb surgery with a thigh tourniquet. Patients were randomly assigned to two groups: each group received treatment with bupivacaine 0.5% containing 1:200,000 adrenaline. Normal saline (B:F o group) or 200 micrograms fentanyl (B:F 200 group) was added to this solution. An immediate increase in systolic and diastolic blood pressure (SBP and DBP) was provoked by tourniquet application in all patients, whilst heart rate (HR) showed no modification and the rate-pressure product (RPP) was hardly influenced in the B:F 200 group. A dramatic reduction in intra-operative supplemental analgesic needs was observed in the B:F 200 group. This group of patients also complained less of tourniquet pain than their counterparts, for the first 30 min of application. Our study underlines the value of fentanyl addition to bupivacaine in extradural blockade in orthopaedic surgery.

Fentanyl and bupivacaine mixtures for extradural blockade.

In a prospective double-blind study, single dose lumbar extradural blockade was instituted in 80 healthy male patients undergoing lower abdominal surgery. Patients were assigned randomly to one of four groups. Each group received treatment with 0.5% bupivacaine 20 ml containing adrenaline 1:200 000. To this solution was added fentanyl 0, 50, 100 or 200 micrograms. The time to regression of analgesic blockade was significantly prolonged (P less than 0.05) only with mixtures containing fentanyl 200 micrograms; no effect was demonstrated with lower doses of the opioid. However, the degree of motor blockade was less intense and incomplete S1-blockade (root-jumping) was more frequent with mixtures containing increasing doses of fentanyl. Patients treated with bupivacaine-fentanyl mixtures shivered less than the control group and showed fewer instances of acute hypotension. The side-effects observed were minor.