High-resolution ultrasound of the supra- and infraclavicular levels of the brachial plexus including the axillary nerve: imaging anatomy based on multiplanar reconstructions and technical guide.

PURPOSE: The diagnosis of peripheral nerve injuries remains challenging. Electromyography and nerve conduction studies do not allow precise localization of the lesion and differentiation between lesions in continuity and non-continuity in cases with complete axonotmesis. Improved ultrasound technology allows the examination of almost the entire peripheral nervous system. The complex sono-anatomy of the brachial plexus outside of the standard scanning planes makes it difficult to access this region. METHODS: On the basis of the Visible Human Project of the National Institutes of Health (NIH), multiplanar reconstructions were created with the 3D Slicer open-source software in the various planes of the ultrasound cross-sections. The ultrasound examination itself and the guidance of the ultrasound probe in relation to the patient were recorded as video files and were synchronized through the audio channel. Subsequently, image matching was performed. RESULTS: Multiplanar reconstructions facilitate visualization of anatomical regions which are challenging to access thereby enabling physicians to evaluate the course of the peripheral nerve of interest in dynamic conditions. Sonographically visible structures could be reproducibly identified in single-frame analysis. CONCLUSION: With precise knowledge of the ultrasound anatomy, the nerve structures of the brachial plexus can also be dynamically assessed almost in their entire course. An instructional video on ultrasound of the brachial plexus supplements this manuscript and has been published on Vimeo.com.

Transdeltoid Approach to Axillary Nerve Repair: Anatomical Study and Case Series.

PURPOSE: In cases of isolated paralysis of the axillary nerve, dissection of the distal stump at the posterior deltoid border can be difficult because of scarring from an injury or previous surgery. To overcome this, we propose dissecting the anterior division of the axillary nerve (ADAN) using a deltoid-splitting approach. We investigated the anatomy of the ADAN as it pertains to the transdeltoid approach and report the clinical application of this approach in 9 patients with isolated axillary nerve injury. METHODS: The axillary nerve and its branches were dissected in 9 fresh cadaver specimens. In the clinical series, 1 patient with a lesion confined to the ADAN underwent nerve grafting. In the remaining 8 patients, the ADAN was repaired by transferring the triceps lower medial head and anconeus (TLMA) motor branch via a single-incision or double-incision posterior arm approach. RESULTS: The posterior division of the axillary nerve does not travel around the humerus. It innervated the posterior deltoid and teres minor muscles. At the posterior margin of the humerus, the ADAN ran adjacent to the teres minor tendon. The ADAN's trajectory on the lateral side of the humerus was 65 mm (SD ± 8 mm) from the midpoint of the acromion. One centimeter from the origin, the ADAN offered a prominent branch to the middle deltoid and wound around the humerus anteriorly at the surgical neck just distal to the infraspinatus tendon. A transdeltoid approach was feasible in all our patients. The TLMA was reached without any tension in the ADAN. Middle deltoid strength in 1 patient who had received a graft scored M3, while anterior and middle deltoid strength in the remaining patients who underwent nerve transfers scored M4. CONCLUSIONS: With axillary nerve lesions, reinnervation of the ADAN is a priority. The transdeltoid approach between the posterior and middle deltoid offers a direct and feasible approach to the ADAN. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

Posterior Deltoid Function After Transfer of Branch to the Long Head Triceps Brachii of the Radial Nerve to the Anterior Branch of the Axillary Nerve.

PURPOSE: The aim of this study was to evaluate the function of the posterior part of the deltoid after nerve transfer of the long head triceps branch of the radial nerve to the anterior branch of the axillary nerve in patients with an upper brachial plexus injury or isolated axillary nerve injury. METHODS: We retrospectively reviewed 26 patients diagnosed with an upper brachial plexus injury or isolated axillary nerve injury who underwent nerve transfer of the long head triceps muscle branch of the radial nerve to the anterior branch of the axillary nerve in our institute between 2012 and 2017. Data on age, sex, the mechanism of injury, the pattern of injury, and operative treatment were collected from medical records. Preoperative and postoperative clinical examinations, including motor powers of shoulder abduction and extension according to Medical Research Council grading, were evaluated. At a minimum of 2 years after the operation, we evaluated the recovery of the posterior deltoid function using the swallow-tail test. RESULTS: Twenty-two patients (84.6%) had recovery of posterior deltoid function confirmed by the swallow-tail test. There were 23 patients (88.5%) who achieved at least Medical Research Council grade 4 of shoulder abduction. CONCLUSIONS: Nerve transfer from the branch to the long head triceps to the anterior branch of the axillary nerve is an effective technique for restoring deltoid function in an upper brachial plexus injury or isolated axillary nerve injury. This technique can provide shoulder abduction and shoulder extension, which are the functions of the posterior deltoid muscle. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

An uncommon, unilateral motor variation of the intercostobrachial nerve.

The intercostobrachial nerve (ICBN) is commonly defined as a purely sensory nerve supplying the skin of the lateral chest wall, axilla, and medial arm. However, numerous branching patterns and distributions, including motor, have been reported. This report describes an uncommon variant of the right ICBN observed in both an 86-year-old white female cadaver and a 77-year-old white male cadaver. In both cases the ICBN presented with an additional muscular branch, termed the "medial pectoral branch", piercing and therefore innervating the pectoralis major and minor muscles. Clinically, the ICBN is relevant during surgical access to the axilla and can result in sensory deficits (persistent pain/loss of sensory function) to this region following injury. However, damage to the variation observed in these cadavers may result in additional partial motor loss to pectoralis major and minor.

Incidence of Axillary Nerve Injury After Arthroscopic Shoulder Stabilization.

PURPOSE: To investigate the incidence of axillary nerve palsy after arthroscopic shoulder stabilization and to measure the distance between the nerve and capsule in shoulders with a capsular lesion. METHODS: This retrospective study included 2,027 shoulders (1,909 patients; 1,433 male and 476 female patients; mean age, 32 years [age range, 13-81 years]) subjected to arthroscopic soft-tissue stabilization for recurrent shoulder instability from 2005 to 2017. The exclusion criteria were bone grafting or transfer and preoperative axillary nerve symptoms. We retrospectively reviewed patient records and investigated the incidence and clinical features of axillary nerve palsy. We measured the closest distance between the axillary nerve and capsule on preoperative magnetic resonance images. RESULTS: Postoperative axillary nerve palsy occurred in 4 shoulders (0.2% of all arthroscopic stabilizations). Capsular repair was performed in 2 shoulders (1.2% of 160 capsular repairs); humeral avulsion of the glenohumeral ligament (HAGL) repair, 1 shoulder (2% of 47 HAGL repairs); and isolated Bankart repair, 1 shoulder (0.05% of 1,941 Bankart repairs). The closest distance between the nerve and capsule was 3.4 ± 3.2 mm in shoulders with capsular or HAGL lesions and less than 1 mm in the 3 shoulders with palsy. The common symptoms in axillary nerve palsy cases were shoulder discomfort, delayed recovery of range of motion, and deltoid weakness and atrophy. A definitive diagnosis was made with electromyography in all cases. Nerve injury by a suture was confirmed during revision surgery in 3 shoulders subjected to capsular or HAGL repair during the initial operation. The palsy was transient and fully recovered in 1 shoulder with isolated Bankart repair. CONCLUSIONS: The incidence of axillary nerve palsy after arthroscopic soft-tissue shoulder stabilization was low but higher in shoulders subjected to capsular or HAGL repair. We should always consider the possibility of axillary nerve palsy in shoulders that require capsular or HAGL repair. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Aberrant bifurcation of intercostobrachial nerve in the axilla: A case report.

Intercostobrachial nerve (ICBN) studies have been undertaken by many authors as it is a highly variable structure with numerous patterns reported worldwide. ICBN is a frequently damaged structure in Axillary Lymph Node Dissection (ALND) or mastectomy. Compression of this nerve, due to the enlargement of axillary lymph nodes from cancer breast may be presented as referred pain along the medial side of arm. Different patterns on the course and distribution of the ICBN have been described in literature. We encountered a lesser known variation of the ICBN where it pierced the second intercostal space as a single trunk and immediately divided into two branches. The putative clinical implications of this aberrant bifurcation are of value in significantly diminishing complications such as pain and sensory disturbances presenting after mastectomy and ALND. The findings of the presentation may be of use by surgeons and interventionists in approaching the area in a more precautious manner.

The change in position of the axillary nerve with rotation of the arm.

The axillary nerve is the most commonly injured nerve around the arm. In the deltopectoral approach, classical teaching states that lateral rotation of the humerus increases the distance between the subscapularis and the axillary nerve. This is the first anatomical study to quantify the distance change between the axillary nerve and subscapularis produced by arm rotation. Eight arms were placed in the supine position and a classical deltopectoral approach was performed. With digital calipers, measurements were made from the closest identifiable margin of the nerve to the inferior extent of the tenotomy. All measurements were made with the arm in 0° abduction and elbow in 90° of flexion, and repeated with the arm in 45° of medial rotation, 0° lateral rotation and 45° of lateral rotation. The mean d Axillary Nerve to subscapularis was recorded as 30.9 mm (95% CI:25.3-36.3), 39.4 mm(95% CI:34.1-44.8), and 46.1 mm (95% CI:41.1-51.2) for 45° MR, 0°, and 45° LR, respectively. Using paired-samples T-testing, the mean change in distance when moving from 45° MR to 0° was +8.5 mm (P < 0.0001), and from 0° to LR 45°, +6.7 mm (P < 0.0001). There is a significant difference in the distance between the subscapularis tenotomy and the axillary nerve with medial and lateral rotation. Laterally rotating the arm increased the distance by 6.7 mm, reaffirming that positioning the glenohumeral joint in a position of LR during subscapular tenotomy is protective against iatrogenic injury of the axillary nerve. Clin. Anat. 32:268-271, 2019. © 2018 Wiley Periodicals, Inc.

Ultrasound-guided anterior approach to the axillary and intercostobrachial nerves in the axillary fossa: an anatomical investigation.

BACKGROUND: The posterolateral and medial aspect of the arm is supplied by the axillary (AXN) and intercostobrachial nerves (ICBN), which are not anaesthetised by an axillary brachial plexus block (ABPB). Blockade of the AXN and the ICBN has been reported in the quadrangular space (QS) posteriorly or by serratus plane block, respectively. An anterior ultrasound-guided approach to block the AXN and ICBN would be desirable to complete an ABPB at a single insertion site. METHODS: After a preliminary dissection study in six cadavers, ultrasound-guided AXN and ICBN injection was performed in 46 Thiel embalmed cadavers bilaterally. Key sonographic landmarks to identify the AXN in the QS are the humerus, teres major muscle, and subscapular muscle. With the same probe position, the ICBN was identified in the subfascial axillary space. Then, 2 ml latex was injected at each nerve and confirmed by dissection. RESULTS: Muscular and bony landmarks were identified in all cadavers. The AXN was seen in 99% in the QS or at the inferolateral margin of the subscapular muscle and surrounded by latex in 96% of cases. Latex spread to the axillary fossa, within the subscapular muscle, or to the radial nerve was noted in 8% of the injections. The ICBN was seen and surrounded by latex in 100% of cases. CONCLUSIONS: We describe a reliable ultrasonographic approach to visualise the AXN and ICBN anteriorly from the conventional ABPB approach as confirmed in this cadaver study.

Effect of a lateral infraclavicular brachial plexus block on the axillary and suprascapular nerves as determined by electromyography - a cohort study.

We aimed to examine to what extent a lateral infraclavicular brachial plexus block affected the axillary and the suprascapular nerve. We included patients undergoing hand surgery anaesthetised with a lateral infraclavicular brachial plexus block. Our primary outcome was the relative change in surface electromyography during maximum voluntary isometric contraction of the medial deltoid muscle (axillary nerve) and the infraspinatus muscle (suprascapular nerve) from baseline to 30 min after the block procedure. A reduction in electromyography of > 50% defined a successful block. The impact of the block on the shoulder nerves was compared with the surgical target nerves of the arm and hand (musculocutaneous, radial, median and ulnar nerves). Twenty patients were included. The medians of the relative changes in the surface electromyography were significantly reduced (both p < 0.001) with 92% for the deltoid muscle and 30% for the infraspinatus muscle, respectively. In total, 18 out of 20 patients had reductions > 50% for the deltoid muscle, which was significantly different from the infraspinatus muscle, where the proportion was 5 out of 20 (p < 0.001). The medians of the relative reductions in electromyography for the arm and hand muscles were 90-96%, similar to the effect on the deltoid muscle. Our results suggest that a lateral infraclavicular block provides block of the axillary nerve comparable to the block of the surgical target nerves. The suprascapular nerve is blocked to a lesser degree. Combining a lateral infraclavicular brachial plexus block with a selective suprascapular block for shoulder surgery warrants further studies.

Luxatio erecta humeri with humeral greater tuberosity fracture and axillary nerve injury.

Luxatio erecta humeri is the rarest type of glenohumeral dislocation, which has been reported to be associated with humeral fracture, rotator cuff tear and neurovascular injury. To our knowledge, a single-sided acute inferior glenohumeral dislocation associated with humeral greater tuberosity fracture and axillary nerve injury has not yet been reported. Here, we reported a traumatic first-time inferior shoulder dislocation from a construction worker who got hyperflexion of the left shoulder when fell and grasped the railing causing. The patient underwent traction counter-traction closed reduction followed by proper immobilization, and rehabilitation therapy. At thirteen months follow-up, the patient had returned to the workload that required high stress on shoulder joint with an excellent outcome.

Injury to the axillary and suprascapular nerves in rotator cuff arthropathy and after reverse shoulder arthroplasty: a prospective electromyographic analysis.

BACKGROUND: Neurologic pre- and postoperative injuries to the axillary and/or suprascapular nerve (SSN) have a higher incidence than expected and may lead to significantly decreased functional outcomes and increased risk of reverse shoulder arthroplasty (RSA) failure. METHODS: Patients who underwent a RSA for rotator cuff tear arthropathy (RCTA) were included from December 2014 to December 2015. This study focused on the clinical (Constant score), radiographic, and pre- and postoperative electromyographic evaluations at 3 and 6 months. RESULTS: Twenty patients met the inclusion criteria. One was lost to follow-up. Preoperatively, 15 patients showed changes on electromyography (9 SSN and 15 axillary nerve lesions); all of them were chronic and disuse injuries. The mean preoperative relative Constant score (rCS) of all included patients was 39 ± 9 (range, 19-64). At 3 months postsurgery, the prevalence of acute injuries for both nerves was 31.5%. At 6 months postsurgery, 2 axillary nerve injuries and 6 SSN injuries remain unchanged, and the rest improved or normalized. The mean postsurgery rCS of the entire cohort at 6-month follow-up was 78 ± 6.5. Mean postoperative rCS for acute postoperative nerve injury was 71 ± 3 for the axillary nerve and 64 ± 5 for SSN. CONCLUSIONS: Axillary and SSN injuries in RCTA have a much higher incidence than expected. Most of these axillary lesions are transient, with an almost complete recovery seen on electromyography at 6 months and with scarce functional impact. However, SSN lesions appear to behave differently, with poor functional results and having a lower potential for a complete recovery.

Evaluation of the relationship between the topographical anatomy in the axillary region of the brachial plexus and the body mass index.

To investigate the topographic anatomy of the median, musculocutaneous, radial and ulnar nerves with respect to the axillary artery and to seek whether these configurations are associated with baseline descriptive data including age, gender, and body-mass index. This cross-sectional trial was carried out on 199 patients (85 women, 114 men; average age: 46.78 ± 15.45 years) in the department of anaesthesiology and reanimation of a tertiary care center. Topographic anatomy of the median, musculocutaneous, radial and ulnar nerves was assessed with ultrasonography. Localization of these nerves with respect to the axillary artery was marked on the map demonstrating 16 zones around the axillary artery. Frequencies of localizations of every nerve in these zones were recorded, and the correlation of these locations with descriptive data including age, gender and BMI was investigated. There was no difference between women and men for the distribution of the median (p = 0.74), ulnar (p = 0.35) and radial (p = 0.64) nerves. However, the musculocutaneous nerve was more commonly located in Zone A13 in men compared to women (p = 0.02). The localization of the median (p = 0.85), ulnar (p = 0.27) and radial (p = 0.88) nerves did not differ remarkably between patients with BMI < 25 kg/m2 and patients with BMI ≥ 25 kg/m2. Notably, the musculocutaneous nerve was more often determined in Zone A10 in cases with BMI ≥ 25 kg/m2 (p = 0.001). Our results imply that the alignment of the musculocutaneous nerve may vary in men and overweight people. This fact must be considered by the anaesthetist before planning the axillary block of brachial plexus. All these informations may enlighten the planning stages of the brachial plexus blockade.

Review and clinical presentation in reverse shoulder arthroplasty in deltoid palsy.

Deltoid palsy is a classical contraindication for reverse shoulder arthroplasty (RSA). However, in cases associating axillary nerve palsy and rotator cuff tear or glenohumeral arthritis, few options remain. We present a case in which combining RSA with transfer of the pectoralis major and upper and middle trapezius transfer provided satisfactory results in a patient suffering of both an irreparable rotator cuff tear and a deltoid palsy.Level of evidence IV.

Quantification of the vasodilatory effect of axillary plexus block. A prospective controlled study.

BACKGROUND: Axillary plexus block is a common method for regional anesthesia, especially in hand and wrist surgery. Local anesthetics (e.g., mepivacaine) are injected around the peripheral nerves in the axilla. A vasodilatory effect due to sympathicolysis has been described, but not quantified. MATERIALS AND METHODS: In a prospective controlled study between October 2012 and July 2013, we analyzed 20 patients with saddle joint arthritis undergoing trapeziectomy under axillary plexus block. Patients received a mixture of mepivacaine 1% and ropivacaine 0.75% in a 3:1 ratio. The measurements were carried out on the plexus side and the contralateral hand, which acted as the control. Laser-Doppler spectrophotometry (oxygen to see [O2C] device) was used to measure various perfusion factors before and after the plexus block, after surgery and in 2-h intervals until 6 h postoperatively. RESULTS: Compared with the contralateral side, the plexus block produced an enhancement of tissue oxygen saturation of 117.35 ± 34.99% (cf. control SO2: 92.92 ± 22.30%, P < 0.010) of the baseline value. Furthermore, blood filling of microvessels (rHb: 131.36 ± 48.64% versus 109.12 ± 33.25%, P < 0.0062), peripheral blood flow (219.85 ± 165.59% versus 129.55 ± 77.12%, P < 0.018), and velocity (163.86 ± 58.18% versus 117.16 ± 45.05%, P < 0.006) showed an increase of values. CONCLUSIONS: Axillary plexus block produces an improvement of peripheral tissue oxygen saturation of the upper extremity over the first 4 h after the inception of anesthesia.

Ultrasound-guided axillary nerve block for ED incision and drainage of deltoid abscess.

Deltoid abscesses are common and painful, often a consequence of injection drug use and seen frequently in emergency departments (EDs). The required incision and drainage can be completed successfully with effective pain relief using a peripheral nerve block. The brachial plexus nerve block works well, however it is technically complex with a low, but potentially serious, risk of complications such as phrenic nerve paralysis. Selective blockade of the axillary nerve eliminates the risks associated with a brachial plexus block, while providing more specific anesthesia for the deltoid region. Our initial experience suggests that the axillary nerve block (ANB) is a technically simple, safe, and effective way to manage the pain of deltoid abscesses and the necessary incision and drainage (I&D). The block involves using ultrasound guidance to inject a 20mL bolus of local anesthetic into the quadrangular space surrounding the axillary nerve (inferior to the posterolateral aspect of the acromion, near the overlap of the long head of triceps brachii and teres minor). Once injected the local will anesthetize the axillary nerve resulting in analgesia of the cutaneous area of the lateral shoulder and the deeper tissues including the deltoid muscle. Further research will clarify questions about the volume and concentration of local anesthetic, the role of injected adjuncts, and expected duration of analgesia and anesthesia. Herein we present a description of an axillary nerve block successfully used for deltoid abscess I&D in the ED.

Axillary nerve lesions after open reduction and internal fixation of proximal humeral fractures through an extended lateral deltoid-split approach: electrophysiological findings.

BACKGROUND: Axillary nerve injuries after shoulder surgery are rare. In most studies, the frequency of injury is usually determined using clinical examinations, but results from intraoperative neuromonitoring studies have revealed higher than expected rates. Few studies have investigated this topic. Our aim was to determine the frequency of axillary nerve lesions after open reduction and internal fixation of proximal humeral fractures by using electrophysiological assessments and to provide a review of the relevant literature. METHODS: This was a retrospective cohort study of 76 consecutive patients who received open reduction and internal fixation of a proximal humeral fracture using a locking plate through a deltoid-splitting approach. We performed a clinical and electrophysiological examination at a minimum follow-up time of 12 months. Functional results were assessed according to the Constant-Murley and Disabilities of the Arm, Shoulder and Hand scores. Electrophysiological examinations comprised electromyography, electroneurography, and motor and somatosensory evoked potentials. The main outcome was the frequency of axillary nerve lesions. RESULTS: Forty patients were monitored for an average of 28 months. The mean raw Constant-Murley score was 61 points, the age- and gender-adjusted score was 71%, and the mean Disabilities of the Arm, Shoulder and Hand score was 33 points. Neurapraxia occurred in 1 patient, axonotmesis with incomplete reinnervation occurred in 3, and complete reinnervation occurred in 3. The latter group was classified as having a temporary axillary nerve lesion. CONCLUSIONS: The 10% rate of permanent axillary nerve lesions in our cohort is higher than expected based on the clinical examination. Electrophysiological assessment is therefore more appropriate to detect axillary nerve injuries.

Aberrant Cutaneous Nerve Loops in the Axilla.

During routine dissection classes, conducted for first year undergraduate medical students, we encountered a rare anatomical variation in relation to the intercostobrachial nerve (ICBN). The ICBN represents the lateral undivided cutaneous branch of second intercostal nerve. In this case, the ICBN formed nerve loops with branches of the lateral cutaneous branch of the third intercostal nerve. These loops eventually gave branches that probably supplied the floor of the axilla and proximal arm. Nowadays, this ICBN is gaining clinical importance during the axillary lymph node dissections and mammary gland surgeries. Damage to the ICBN, may results in the sensory deficits in patients undergoing surgery. In our case report, ICBN was making aberrant nerve loop along with the branches from the third intercostal nerve. Knowledge regarding the origin, formation and route of ICBN is of clinical significance to axillary surgeons, radiologist and anesthesiologists.

Quadrilateral Space Syndrome Treated with Ultrasound-Guided Corticosteroid Injection: A Case of Isolated Teres Minor Atrophy and Review of the Literature.

Quadrilateral space syndrome (QSS) is a rare orthopedic condition caused by compression, entrapment, or injury to the axillary nerve or posterior humeral circumflex artery as they arise from the quadrilateral space. QSS can present with point tenderness over the quadrilateral space and weakness and paresthesia in the axillary nerve distribution. It is commonly associated with repetitive overhead activities and is seen in athletes engaging in such activities. Here we report a case of QSS in a 42-year-old male weight lifter who presented with pain and soreness in the posterior aspect of his right shoulder radiating around his arm as well as slight weakness of his right shoulder of a few weeks duration. MRI results of his shoulder demonstrated moderate atrophy and fatty infiltration of the teres minor. His diagnosis of QSS was confirmed with electro diagnostic testing which showed axillary neuropathy. He was treated with ultrasound guided corticosteroid injections and gained relief from this treatment. His axillary neuropathy was shown to be resolving on repeat electro diagnostic testing at six-months follow-up. Here we report a case of QSS and provide a brief review of the literature.

[Nerve transfer between the intercostal nerves and the motor component of the musculocutaneous nerve. Anatomical study of feasibility]. / Transfert nerveux entre les nerfs intercostaux et la composante motrice du nerf musculocutané. Étude anatomique de faisabilité.

INTRODUCTION: The intercostal nerves (ICN) transfer to the musculocutaneous nerve (MCN) can restore elbow flexion in complete brachial plexus palsy. The last cases our service dealt with, allowed our staff to observe two different situations. In the 2 first patients, we were able to proceed with an intraneurodissection of the MCN motor component up to the axillary cavity level, while on the third case such dissection could not be performed as high. The aim of this work is to assess the feasibility of a transfer on the MCN's motor component. MATERIAL AND METHODOLOGY: We conducted a series of 5 cadaver dissections of the MCN and ICN on the anatomy laboratory. Using magnifying loupes to perform an intraneurodissection, we were able to split the motor and sensory fibers as they stood out. It would help motor recuperation avoiding directional error on sensitive component. RESULTS: The ICN can be sutured on the motor component of the MCN, provided the dissection is very minutious. DISCUSSION: The intraneurodissection of the MCN up to the axillary cavity level is possible as the interfascicular exchanges are scarce there. Publications already refer to the possibility of a nerve transfer between the ICN and the motor component of the MCN. Therefore, our researches suggest that such a procedure can be considered for routine procedures. CONCLUSION: The neurotization is one of the latest breakthroughs in terms of brachial plexus surgery. We are hopeful that anatomical researches could lead to optimization possibilities.

Ultrasound-Guided Single-Injection Infraclavicular Block Versus Ultrasound-Guided Double-Injection Axillary Block: A Noninferiority Randomized Controlled Trial.

BACKGROUND: Single-injection ultrasound-guided infraclavicular block is a simple, reliable, and effective technique. A simplified double-injection ultrasound-guided axillary block technique with a high success rate recently has been described. It has the advantage of being performed in a superficial and compressible location, with a potentially improved safety profile. However, its effectiveness in comparison with single-injection infraclavicular block has not been established. We hypothesized that the double-injection ultrasound-guided axillary block would show rates of complete sensory block at 30 minutes noninferior to the single-injection ultrasound-guided infraclavicular block. METHODS: After approval by our research ethics committee and written informed consent, adults undergoing distal upper arm surgery were randomized to either group I, ultrasound-guided single-injection infraclavicular block, or group A, ultrasound-guided double-injection axillary block. In group I, 30 mL of 1.5% mepivacaine was injected posterior to the axillary artery. In group A, 25 mL of 1.5% mepivacaine was injected posteromedial to the axillary artery, after which 5 mL was injected around the musculocutaneous nerve. Primary outcome was the rate of complete sensory block at 30 minutes. Secondary outcomes were the onset of sensory and motor blocks, surgical success rates, performance times, and incidence of complications. All outcomes were assessed by a blinded investigator. The noninferiority of the double-injection ultrasound-guided axillary block was considered if the limits of the 90% confidence intervals (CIs) were within a 10% margin of the rate of complete sensory block of the infraclavicular block. RESULTS: At 30 minutes, the rate of complete sensory block was 79% in group A (90% CI, 71%-85%) compared with 91% in group I (90% CI, 85%-95%); the upper limit of CI of group A is thus included in the established noninferiority margin of 10%. The rate of complete sensory block was lower in group A (proportion difference of 12% [95% CI, 2-22]; P = 0.0091), as was surgical success rate (82% [95% CI, 74%-89%] vs 93% [95% CI, 86%-97%]; proportion difference of 11% [95% CI 1-20]; P = 0.0153). Sensory block onset also was slower in group A (log rank test P = 0.0020). Performance times were faster in group I (231 seconds [95% CI, 213-250]) than in group A (358 seconds [95% CI, 332-387]; P < 0.0001). No statistically significant difference was observed for vascular puncture, paresthesia during block performance, or procedure-related pain. No neurologic complication was noted at follow-up. CONCLUSIONS: We failed to demonstrate that the rate of complete sensory block of the double-injection axillary block is noninferior to the single-injection infraclavicular block. However, the rate of complete sensory block at 30 minutes is statistically significantly lower with the axillary block. The ultrasound-guided single-injection infraclavicular block thus seems to be the preferred technique over the axillary for upper arm anesthesia.