Axillary block by "selective" injections at the nerves involved in surgery using a peripheral nerve stimulator: a comparison with a "standard" triple-injection technique. Radial plus musculocutaneous nerve stimulation for axillary block is inferior to triple nerve stimulation with 2% mepivacaine. A comparison of three methods of axillary brachial plexus anaesthesia. [Axillary brachial plexus anesthesia. How many nerve stimulation responses do we look for?]. Axillary brachial plexus block using peripheral nerve stimulator: a comparison between double- and triple-injection techniques. Comparison of the clinical efficacy of three perivascular techniques for axillary brachial plexus block. A comparison of four stimulation patterns in axillary block. Axillary brachial plexus blockade: an evaluation of three techniques. A comparison of three methods of axillary approach to brachial plexus blockade for upper extremity surgery. [Comparison of transarterial and multiple nerve stimulation techniques for axillary block using lidocaine with epinephrine.]. Comparison of two neurostimulation techniques for axillary brachial plexus blockade. Clinical and radiological comparison of perivascular and transarterial techniques of axillary brachial plexus block. Readiness for surgery after axillary block: single or multiple injection techniques. Comparison of transarterial and multiple nerve stimulation techniques for an initial axillary block by 45 mL of mepivacaine 1% with adrenaline. Comparison of transarterial and multiple nerve stimulation techniques for axillary block using a high dose of mepivacaine with adrenaline. Low dose axillary block by targeted injections of the terminal nerves. Axillary plexus block using a peripheral nerve stimulator: single or multiple injections. Double-injection method using peripheral nerve stimulator is superior to single injection in axillary plexus block.
A triple-injection technique (injections at the median, musculocutaneous, and radial nerves) for axillary block affords a high incidence of complete block (all the nerves below the elbow). However, in certain surgeries, only 1 or 2 nerves are involved in the surgical field. The aim of this prospective randomized study was to test the effectiveness of surgical anesthesia of a "selective" approach in which only the nerves involved in surgery were electrically located and injected.
                Three types of surgery were selected. Type 1 included surgery on the fifth finger, type 2 included superficial surgery (without bone involvement) on the palm or on the dorsum of the hand, and type 3 included any surgery on the first 3 fingers. For each type, 138 patients were enrolled and divided into 2 groups: group SEL in which only the nerves involved in the surgical field (1 or 2) were located and injected and group TNS in which a standard triple-nerve stimulation technique was used.
                A lower rate of surgical anesthesia (84% vs 92%; P G 0.05)was recorded in group SEL considered as a whole: this was mainly due to the significant difference recorded in type 2 surgery (75% vs 93%;P G 0.05). More patients needed intravenous administration of fentanyl for tourniquet pain (18% vs 8%; P G 0.005) and of midazolam for intraoperative anxiety (20% vs 8%; P G 0.005) in group SEL considered as a whole. In type 1, improved patient comfort at block performance(P G 0.05), a 7-min saving on total anesthetic time (P G 0.001), and a higher need for midazolam administration (P G 0.05) were recorded in group SEL. In type 2, a higher need for midazolam administration(P G 0.05) was recorded in group SEL. In type 3, no clinically significant differences between the groups were recorded.
                A standard triple-nerve stimulation technique seems to be preferable to the selective approach even when a limited number of nerves are involved in the surgical field. To compare the extent of sensory and motor block with two different nerve stimulation techniques in axillary blocks.
                Prospective, randomized, investigator-blinded study.
                Ambulatory surgery unit of a university hospital.
                60 ASA physical status I, II, and III patients undergoing surgery at or below the elbow.
                Patients receiving axillary block were randomized into two nerve stimulation groups with either radial plus musculocutaneous or triple nerve stimulation (radial, median, and musculocutaneous nerves). Thirty milliliters of plain 2% mepivacaine was given to all patients either in a single or fractionated dosing for radial or for radial and median nerves, according to group assignment. Five milliliters of plain 1% mepivacaine for the musculocutaneous nerve was given to all patients.
                Blocks were assessed at 10, 20, and 30 minutes. Rates of supplementation given as a result of insufficient surgical anesthesia were also noted.
                Statistically significantly higher rates of anesthesia at the cutaneous distributions of median and medial cutaneous of the arm nerves with multiple nerve stimulation at 30 minutes were found as compared with radial plus musculocutaneous nerve stimulation. The rate of supplementation was lower with multiple nerve stimulation.
                Radial plus musculocutaneous nerve stimulation showed lower efficacy of axillary block than did triple nerve stimulation when using 2% mepivacaine. One hundred patients scheduled for elective outpatient hand surgery had blockade of the axillary brachial plexus by one of three techniques; insertion of a catheter into the brachial plexus sheath (n = 25), use of paraesthesia (n = 50) or use of the nerve stimulator (n = 25) to localise the plexus. Only two patients required general anaesthesia for the planned surgery. Assessment of the dermatomes blocked did not demonstrate a statistical difference between the success rates of the three groups. The more nerves detected in the paraesthesia and the nerve stimulator groups before injection of local anaesthetic the higher the success rate of the block. We advocate use of the nerve stimulator technique in view of the possible risk of neurological damage associated with paraesthesia and the technical difficulties with the catheter technique, for routine brachial plexus blockade. To determine whether axillary block with nerve stimulation involving the location of four motor responses is more effective than other techniques using fewer locations, without increasing patient discomfort or the rate of complications.
                Prospective, randomized single blind study enrolling 100 patients undergoing orthopedic surgery under axillary block with nerve stimulation. Patients were randomly assigned to five groups of 20 patients: in group A, 4 motor responses were located; in group B three were located (musculocutaneous nerve and two more); in group C two responses, the musculocutaneous nerve and one more; in group D two non-musculocutaneous responses; and in group E only one non-musculocutaneous response was located (medial, cubital or radial). We used 40 ml of 1% mepivacaine. Data collected were location of responses, duration of blockade, adverse events occurring during the technique; level of motor and sensory block; tolerance to the tourniquet; level of patient discomfort; and presence of complications.
                A full sensory block was achieved for 100% in group A, 90% in group B, 60% in group C, 75% in group D and 40% in group E. Patient discomfort was similar in all groups. One patient continued to suffer postoperative neurologic dysfunction three months after the block.
                Locating 4 responses gives the greatest degree of assurance of obtaining full sensory block without increasing patient discomfort or rate of complications. The multiple-injection technique for axillary block, in which the main 4 nerves of the plexus are located by a nerve stimulator and separately injected, has been shown to produce a high success rate. However, this technique may prove to be more difficult and time-consuming than other methods. Therefore, a simplified technique, with a reduced number of injections, might be desirable. A comparison between 2- and 3-injection techniques was made in the present double-blind study.
                One hundred patients were randomly allocated to 2 groups. In group 3N, the radial, median, and musculocutaneous nerves were located by a nerve stimulator and injections made. In group 2N, the radial and median nerves were located and injections made. Forty milliliters of local anesthetic was used.
                A greater success rate for anesthetizing the musculocutaneous nerve was found in group 3N (98% v 80%; P <.005). No differences between the groups were found in the success rate for blocking the radial, median, and ulnar nerves. The rate of complete block (all the sensory areas distal to the elbow) was 90% in group 3N and 76% in group 2N. The time to perform the block was shorter in group 2N (5 +/- 1 v 6 +/- 1 minutes; P <.001).
                The 2-injection technique offers a success rate in blocking the 3 nerves innervating the hand similar to that obtained with the 3-injection technique. The latter approach should be considered when the musculocutaneous nerve distribution is involved in the surgical area. This study compared the efficacy of three perivascular techniques of axillary block.
                In group 1, all of the local anesthetic was injected after advancing the needle through the axillary artery (back of artery, n = 20); in group 2, after withdrawing slightly from the artery (front of artery, n = 20); and in group 3, half of the anesthetic was injected after advancing through and half after withdrawing from the axillary artery (half and half, n = 20). The local anesthetic used for the axillary block was 50 ml of 1.5% mepivacaine with epinephrine 1:200,000.
                The groups did not differ significantly in the incidence of analgesia or anesthesia expected in the median nerve distribution, where there was a significantly lower incidence of anesthesia in the back of the artery group. This group also had a slower onset of anesthesia for the median and the medial antebrachial cutaneous nerves.
                There was no significant difference in the number of patients requiring supplementation, with five patients in the back group (25%), three patients in the front group (15%), and one patient in the half and half group (5%) requiring supplementation for the surgical procedure. Insufficient spread of the local anesthetic toward the retroarterial region of the neurovascular space may be responsible for inconsistent anesthesia of the upper limb after single-injection axillary block. We hypothesized that injection of the local anesthetic on a single radial-nerve stimulation would produce the same extent of anesthesia as either a single median-nerve stimulation, a double-stimulation technique (radial and musculocutaneous nerves), or a triple-stimulation technique (radial, musculocutaneous, and median nerves).
                One hundred twenty patients were randomly assigned to receive an axillary block by either median-nerve, radial-nerve, radial-nerve plus musculocutaneous-nerve, or triple-nerve stimulation with 40 mL of plain 1.5% mepivacaine. Patients were assessed for sensory block by the pinprick method at 5 and 20 minutes.
                Radial-nerve stimulation produced more extensive anesthesia than did median-nerve stimulation. The rate of anesthesia at 20 minutes in the median-nerve cutaneous distribution was similar after median-nerve stimulation or radial-nerve stimulation. The ulnar nerve was more frequently blocked at 20 minutes after radial-nerve stimulation than after median-nerve stimulation. Extent of anesthesia at 20 minutes after radial-nerve plus musculocutaneous-nerve stimulation was similar to that produced by triple-nerve stimulation, except for lower rates of anesthesia that corresponded to the median nerve. All of the differences were statistically significant.
                Musculocutaneous-nerve stimulation and radial-nerve stimulation play predominant roles in the success of axillary brachial plexus block, although a triple-nerve stimulation technique is still required to produce complete anesthesia of the upper limb. Surgical procedures to the distal humerus, elbow, and proximal forearm are ideally suited to regional anesthetic techniques. Selection of the preferred approach is determined by the innervation of the surgical site, the risks of regional anesthesia-related complications, and the preference and experience of the anesthesiologist. The axillary approach to the brachial plexus is the most commonly used because of its ease of performance, patient acceptance, safety, and reliability, particularly for hand and forearm surgery. Nerve location technique does not affect success rate with the supraclavicular and interscalene approaches but it does with axillary approaches. The purpose of this study was to evaluate three techniques of plexus identification in axillary blockade. Sixty-nine American Society of Anesthesiologists grade I to II patients who had undergone orthopedic or traumatological surgical procedures on the upper extremity during a period of 1 year were chosen. After premedication, patients were divided randomly into three groups according to the technique of plexus identification. Group A (n = 23) consisted of those treated with the Winnie technique; group B (n = 23) consisted of those treated with the transarterial technique; group C (n = 23) consisted of those treated with the combination technique. Axillary blockade performed using the combined technique had higher a success rate than blockade performed with the transarterial and Winnie techniques. Our results suggest that all three techniques are reliable for axillary blockade. But the onset, complete blockade time, and quality of analgesia were better with the combined technique than with the transarterial and Winnie techniques. nan High-dose transarterial technique results in highly effective axillary block. The multiple nerve stimulation technique (MNS) requires more time and experience. This prospective study aimed at comparing onset and success rate of multiple-injection axillary brachial plexus block using two methods of nerve location: transarterial or multiple nerve stimulation technique.
                Axillary block was initially induced with 800 mg lidocaine with epinephrine. The transarterial group received deeply injected 30 mL of 1.6% lidocaine with epinephrine, and 20 mL superficially to the axillary artery. For the multiple nerve stimulation group, three terminal motor nerves were electrolocated and blocked with 20 mL, 20 mL and 10 mL. Blockade was considered effective when analgesia was present in all sensory nerves distal to the elbow.
                Onset (8.8 +/- 2.3 min versus 10.2 +/- 2.4 min; p-value = 0.010) was significantly shorter in the transarterial group. Complete sensory block of all four nerves (median, ulnar, radial and musculocutaneus) was achieved in 92.5% versus 83.3% for multiple nerve stimulation group and transarterial group, respectively, without significant difference (p = 0.68). Musculocutaneous nerve was significantly easier to be blocked with the aid of peripheral nerve stimulator (p = 0.034).
                Both MNS technique for axillary block with nerve stimulator (3 injections) and transarterial technique (2 injections) promote similar results. Musculocutaneous nerve is more easily blocked with the aid of peripheral nerve stimulator. MNS technique has required less supplementary blocks and has delayed beginning of surgery. This prospective, randomized, double-blind study compared two techniques of axillary brachial plexus block using a peripheral nerve stimulator. Both groups received initial musculocutaneous nerve block followed by either a single injection on median nerve stimulation (group 1) or a double injection divided between median and radial nerves (group 2). All 60 patients received a total of 30 ml of lidocaine 15 mg/ml with epinephrine 5 microg/ml. Complete sensory blockade of all six peripheral nerves occurred in 53% and 97% of patients in groups 1 and 2, respectively (P<0.001), with a more rapid onset of blockade occurring in group 2 patients (P<0.001). Complete motor blockade was evident in 30% and 83% of patients in groups 1 and 2, respectively (P<0.001). The perivascular technique of axillary brachial plexus block results in incomplete block of radial and musculocutaneous nerves in 10-20% of patients. With the transarterial technique and a large dose of mepivacaine, success rates of 99% have been reported. We have compared the clinical efficacy of these techniques in 50 patients using 1% mepivacaine 45 ml with adrenaline. If required, the block was supplemented with additional blocks of single nerves or i.v. alfentanil. Additionally, eight patients in each group were studied with computed tomography after contrast medium was added to 0.5% bupivacaine 40 ml. There were no statistically significant differences in sensory or motor block between the groups at 20 min or in the plasma concentrations of mepivacaine measured 0-45 min after injection. In the CT scans, both proximal and distal spread of the contrast medium were more common after perivascular than after transarterial block. The distribution of the contrast medium was not related to the efficacy of the block. We have assessed prospectively the time to readiness for surgery following axillary block (sum of block performance and latency times) in 80 patients. The brachial plexus was identified using a nerve stimulator, and anaesthetized with 45 mL of mepivacaine 1% with adrenaline 5 micrograms mL-1. In group 1 (single injection) the whole volume of mepivacaine was injected after locating only one of the plexus nerves. In group 2 (multiple injections) at least three plexus nerves were located, and the volume of mepivacaine was divided between them. Sensory block was assessed by a blinded observer every 10 min. Patchy analgesia was supplemented after electrolocating the unblocked nerves after 20, 30 or 40 min. The patient was pronounced ready for surgery when analgesia was present in all areas to be operated upon, which always included the three nerves to the hand. The single injection technique required less time for block performance (mean 5.5 min) than multiple injections (mean 9.5 min), P < 0.0001. However, latency of the block was longer and the requirement for supplemental nerve blocks was greater, after single injections (33 min and 57%) than after multiple injections (15.5 min and 7%, respectively), P < 0.0001. As a result, readiness for surgery was achieved faster in group 2 (25 min), than in group 1 (38.5 min), P < 0.0001. After supplementation, block effectiveness was 100% in group 1 and 98% in group 2 (NS). The frequency of adverse effects (vessel puncture or paraesthesia) was similar in both groups. No neurological sequelae were observed. We conclude that the multiple injection technique takes longer to perform than single injection, but that readiness for surgery is faster because of shorter block latency and better spread of analgesia. The single-injection axillary block is rapidly performed but gives unpredictable results. Axillary block by multiple nerve stimulation technique (MNS) gives better results, but takes longer to perform. Transarterial (TA) injections of high doses of local anaesthetics are very successful. This double-blind study compared both block effectiveness and anaesthesiologic time consumption in 100 patients, having an axillary block by either TA or MNS techniques.
                45 mL of 1% mepivacaine with adrenaline 5 microg/mL was used in each patient. Five mL was injected subcutaneously. In the TA group, 20 mL was injected deep to, and 20 mL superficial to the axillary artery. In the MNS group, four terminal motor nerves were electrolocated in the axilla, and injected with 10 mL each. Analgesia was assessed every 10 min and when needed supplemented after 30 min. The block was considered successful when analgesia was present in all sensory nerve areas distal to the elbow.
                MNS group required 10+/-2 min (mean+/-1 SD) for the initial block performance compared with 7+/-2 min for TA group, P<0.001. Latency of the initial block was shorter and the frequency of supplemental analgesia lower in the MNS group (mean 17 min and 12%), than in the TA group (25 min and 38%, respectively), P<0.001. All incomplete blocks were successfully supplemented by electrolocating the unblocked nerves. However, the total time to obtain 100% success rate was shorter in the MNS group (30 min), than in the TA group (38 min), P<0.001. The adverse effects (accidental intravascular injections and axillary haematomas) were fewer in the MNS group.
                In the hands of anaesthetists experienced in nerve electrolocation, the MNS technique of an initial axillary block by four separate injections of 10 mL of mepivacaine produces faster and more extensive block than the TA technique by two separate injections of 20 mL. Hence, the MNS technique requires fewer supplementary blocks and results in faster patient readiness for surgery than the TA technique. High-dose transarterial (TA) technique results in high effectiveness of the axillary block. The technique is fast and simple, but does not produce a satisfactory success rate when using the manufacturer's recommended dose of mepivacaine. The multiple nerve stimulation (MNS) technique requires more time and experience. This double-blind study compared effectiveness, safety and the time used to obtain an effective analgesia in 101 patients, having an axillary block by either TA or MNS techniques.
                Mepivacaine with adrenaline (MEPA), 850 mg, was used for the initial block. Five millilitres of 1% solution was injected subcutaneously. In the TA group, 20 mL of 2% solution was injected deep to, and 20 mL superficial to the axillary artery. In the MNS group, four terminal motor nerves were electrolocated in the axilla, and injected with 10 mL each. Analgesia was assessed every 10 min and, when needed, supplemented after 30 min. The block was effective when analgesia was present in all sensory nerve areas distal to the elbow.
                The MNS group required median 11 min for block performance compared with 8 min for the TA group (P < 0.001). Latency of the initial block was shorter and the frequency of supplemental analgesia lower in the MNS group (median 10 min and 6%) than in the TA group (30 min and 36%, respectively), P < 0.001. All incomplete blocks were successfully supplemented. However, the total time to obtain an effective block was shorter in the MNS group (23 min) than in the TA group (37 min), P < 0.001. Two patients in each group had signs and symptoms of systemic toxicity, the most serious being atrial fibrillation and temporary loss of consciousness in a cardiovascularly medicated patient. The local adverse effects (intravascular injections and haematomas) were fewer in the MNS group, P < 0.001.
                The MNS technique of axillary block by four injections of 10 mL of 2% MEPA produces faster and more extensive block than the TA technique by two injections of 20 mL. Therefore, the MNS technique requires fewer supplementary blocks and results in faster patient readiness for surgery. However, high doses of MEPA may result in dangerous systemic toxic reactions. To compare anesthetic time, success rate and adverse effects of axillary block by single or multiple injections of local anesthetic.
                Two groups of patients were studied. In group T (targeted injections, n = 53) the four terminal nerves were located by electrical stimulation, and anesthetized with 5 ml mepivacaine 1% with epinephrine 5 microg x ml(-1) (MEPE). In group S (single injection, n = 53) 80 mL MEPE 1% were injected into the neurovascular sheath, transarterially or after eliciting paresthesia. Patchy blocks were supplemented after 30 min. The patient was ready for surgery when analgesia was present in all areas distal to the elbow.
                The block was complete at 11 min (6-15) in Group T and 7 min (5-13) in group S, P<0.01. Supplementation was required in 46% in group S compared with 13% in group T P<0.001: anesthesia time was 32 min (19-52) in group T, and 39 min (16-58) in group S, P = 0.02. The average doses of MEPE were 3.5 mg x kg(-1) (2.4-5.6) in T group and 12.0 mg x kg(-1) (8.9-16.4), in S group. However, 22% of patients in group T and 4% in group S reported tourniquet pain, P = 0.02. Paresthesia was elicited in 42% of patients in group S and 8% in group T, P<0.001.
                Small targeted injections of MEPE reduce total anesthetic time, give better spread of analgesia in the hand and forearm, and may be safer than a single large injection. This prospective, randomized, double-blind study was undertaken to evaluate the success rates of axillary brachial plexus block performed with the help of a peripheral nerve stimulator when either one, two or four of the major nerves of the brachial plexus were located. Seventy-five patients undergoing upper limb surgery were randomly allocated to one of the following five groups according to the nerve and number of nerves to be located; G-1: musculo-cutaneous, radial, median and ulnar nerves; G-2: musculo-cutaneous plus one of the other three nerves; G-3: radial nerve; G-4: median nerve; G-5: ulnar nerve. The sensory block was evaluated before surgery and cutaneous anaesthesia was considered to be present when the needles of a Wartenberg Pinwheel were no longer felt in all the dermatomes of the nerves implicated in the surgical site. Otherwise, the block was considered to need completion before surgery. Only one out of the 15 patients in G-1 and G-2 needed completion of their block before surgery whereas seven out of 15 for G-3 and eight out of 15 for G-4 and G-5 needed completion of their block (P less than 0.01). We conclude that when performing an axillary block with the help of a peripheral nerve stimulator, stimulation of the musculo-cutaneous nerve and one other nerve or stimulation of all four major nerves of the brachial plexus gives a higher success rate than stimulation of only one nerve, whether the stimulated nerve is the median, radial or ulnar. Axillary block using a single-injection method does not always provide effective analgesia. This study examined whether a double axillary block injection technique is superior to a single injection axillary block.
                Fifty patients were randomly allocated to two groups. In group I (single injection), the whole volume of local anesthetic (0.7 mL/kg) was injected after locating only one of the median, radial, or ulnar nerves. In group 2 (double injection), half of the volume was injected after locating one nerve and the other half after locating another peripheral nerve. Bupivacaine 0.5% and prilocaine 1% (1:1 volumes) were used as local anesthetic. A peripheral nerve stimulator was used to identify the nerves. Sensory block of seven nerves and motor block of four nerves were tested after 40 minutes.
                Complete sensory and motor block (scores 2 or 3 on scale 0-3) in all four main nerves (median, ulnar, radial, musculocutaneous) was achieved in 3 (12%) versus 20 (80%) patients in groups 1 and 2, respectively (P = .000001). Primary success rate (no need for supplemental nerve block) was 52% in group 1 and 92% in group 2 (P = .0016).
                A double-injection method in axillary block provides excellent analgesia and motor block compared with a single-injection method. Moreover, the need for supplemental nerve blocks is significantly decreased.
This review provides evidence that multiple injection techniques using nerve stimulation for axillary plexus block produce more effective anaesthesia than either double or single injection techniques. However, there was insufficient evidence for a significant difference in other outcomes, including safety.