Anatomic basis of vascularized ulnar nerve graft by the pedicle of the superior collateral ulnar artery

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Brachial plexus anatomy

The brachial plexus may be visualized simply as beginning with five nerves and terminating in five nerves. It begins with the anterior rami of C5, C6, C7, C8, and the first thoracic nerve. It terminates with the formation of the musculocutaneous, median, ulnar, axillary, and radial nerves. The intermediate portions are displayed in sets of threes: three trunks are formed, followed by three divisions, then three cords. Each trunk gives rise to two divisions and each cord gives rise to two branches. The lateral cord divides into the musculocutaneous nerve and the lateral branch of the median nerve. The medial cord divides into the medial branch of the median nerve and the ulnar nerve. The posterior cord divides into the axillary and the radial nerves. The anatomy of the brachial plexus can be confusing, especially because of frequent variations in length and caliber of each of its components.     

Endoscopic anatomy of the axillary brachial plexus: examination of cadavers and implications for anesthesia

OBJECTIVE: To identify the structures of the brachial plexus using fiberoptic techniques, determine the most useful approach, and visualize the introduction of instruments used in anesthesia. MATERIAL AND METHODS: Formalin-treated a ndcryopreserved cadavers were studied with a 4-mm fiberoptic endoscope, an arthroscope for small joints, and nerve-stimulation needles through which a catheter could be introduced. The arm and elbow were dissected to isolate the humeral artery and the medial, radial, and cubital nerves. The fiberoptic endoscope was advanced along each nerve until the axilla, where the neurovascular structures of the plexus were identified. The axilla was punctured with a nerve stimulation needle and the catheter was passed through the needle while its movement was observed with the fiberoptic endoscope. Then, the axilla was punctured with the arthroscope as if it were the needle. RESULTS: In cryopreserved and formalin-treated cadavers, the fiberoptic endoscope could be passed as far as the axilla by following the medial nerve but not by following the cubital or radial nerves. We were able to identify the humeral artery and medial nerve in the axilla and to observe entry of the needle and progression of the catheter. The arthroscope could be introduced in the axilla as if it were a needle and the humeral artery and medial nerve could be identified. CONCLUSIONs: The inside of the neurovascular bundle of the brachial plexus can be visualized using afiberoptic endoscope advanced from the elbow or using an arthroscope introduced in the axilla. Although we are a long way from being able to see what we are doing, this is a first step towards direct visualization of the major structures of the axillary brachial plexus.     

Injuries of the terminal branches of the infraclavicular brachial plexus: patterns of injury, management and outcome

We reviewed 101 patients with injuries of the terminal branches of the infraclavicular brachial plexus sustained between 1997 and 2009. Four patterns of injury were identified: 1) anterior glenohumeral dislocation (n = 55), in which the axillary and ulnar nerves were most commonly injured, but the axillary nerve was ruptured in only two patients (3.6%); 2) axillary nerve injury, with or without injury to other nerves, in the absence of dislocation of the shoulder (n = 20): these had a similar pattern of nerve involvement to those with a known dislocation, but the axillary nerve was ruptured in 14 patients (70%); 3) displaced proximal humeral fracture (n = 15), in which nerve injury resulted from medial displacement of the humeral shaft: the fracture was surgically reduced in 13 patients; and 4) hyperextension of the arm (n = 11): these were characterised by disruption of the musculocutaneous nerve. There was variable involvement of the median and radial nerves with the ulnar nerve being least affected. Surgical intervention is not needed in most cases of infraclavicular injury associated with dislocation of the shoulder. Early exploration of the nerves should be considered in patients with an axillary nerve palsy without dislocation of the shoulder and for musculocutaneous nerve palsy with median and/or radial nerve palsy. Urgent operation is needed in cases of nerve injury resulting from fracture of the humeral neck to relieve pressure on nerves.     

The anatomy of the extrathoracic intercostobrachial nerve

BACKGROUND: In the past decade surgeons have become increasingly aware of the morbidity caused by the division of the intercostobrachial nerve (ICBN) during axillary dissection. To prevent this problem and also to explain its variable occurrence, a detailed knowledge of the anatomy of the nerve is required. METHODS: Twenty-eight axillary dissections were performed demonstrating the anatomy of the ICBN. RESULTS: In all dissections the nerve originated from the second intercostal space, with contributions from the first and third intercostal nerve each on one occasion. The posterior axillary branch was constant but may branch early, simulating a second nerve. The ICBN had a variable relationship to the lateral thoracic vein: anterior, posterior or wrapping around it. In 36% there was a connection to the medial cord of the brachial plexus in the axilla. In the upper arm the nerve lies in the subcutaneous fat; in the majority it supplied at least the proximal half of the arm, and in one-third it reached the level of the elbow joint. In 18% there was a connection to the medial cutaneous nerve of the arm. CONCLUSION: The ICBN and its main branch (the posterior axillary nerve) were constant in all dissections. But its origin, size, connection to the brachial plexus and medial cutaneous nerve of the arm were variable, as was its ultimate destination in the arm.     

Applied anatomy for upper limb nerve blocks

The brachial plexus derives from C5, C6, C7, C8 and T1 nerves. It is made up of five roots, between the scalene muscles, three trunks (upper, middle and lower) lying in the posterior triangle, each of which divide into anterior and posterior divisions behind the clavicle to form lateral, medial and posterior cords in the upper axilla. The plexus gives rise to the definitive motor and cutaneous nerve supply to the upper limb. The plexus can be blocked by local anaesthetic infiltration at its root/trunk level in the fascial sheath compartment between the scalenes, or as it crosses the first rib. Block can also be performed around the axillary artery. Peripherally, the nerves may be blocked at the elbow, wrist or finger level.     

Applied anatomy for upper limb nerve blocks

The brachial plexus derives from C5, C6, C7, C8 and T1 nerves. It is made up of five roots, between the scalene muscles, three trunks (upper, middle and lower) lying in the posterior triangle, each of which divide into anterior and posterior divisions behind the clavicle to form lateral, medial and posterior cords in the upper axilla. The plexus gives rise to the definitive motor and cutaneous nerve supply to the upper limb. The plexus can be blocked by local anaesthetic infiltration at its root/trunk level in the fascial sheath compartment between the scalenes, or as it crosses the first rib. Block can also be performed around the axillary artery. Peripherally, the nerves may be blocked at the elbow, wrist or finger level.     

Block of the brachial plexus branches by the humeral route. A prospective study in 503 ambulatory patients. Proposal of a nerve-blocking sequence

BACKGROUND: Brachial plexus is usually approached by the supraclavicular or axillary route. A technique for selective blockade of the branches of the plexus at the humeral canal using electrolocation has recently been proposed. The aim of the present study was to assess the feasibility of this technique in the ambulatory patient and to determine the optimal sequence of nerve-blocking. METHODS: The nerves originating from the brachial plexus were located in the humeral canal, at the junction of the proximal and the middle third of the arm, with a stimulator and blocked using either lidocaine or a mixture of lidocaine and bupivacaine, depending on the anticipated duration of surgery. The minimal stimulating intensity eliciting an adequate response, type of local anaesthetic and injected volume, and time of onset of surgical anaesthesia were collected. RESULTS: The study included 503 consecutive ambulatory patients due to undergo surgery of the elbow, wrist or hand in one year. Suitable anaesthesia was obtained with the humeral blockade in 82.1% of cases. In the remaining 17.9%, an additional block at the elbow was required, mainly for ulnar and median nerves. The onset times of sensory blocks were the longest for the median nerve, similar for the radial and ulnar nerves, shorter for the musculocutaneous nerve and the shortest for the medial brachial and antebrachial cutaneous nerves. The difference was more significant with the lidocaine-bupivacaine mixture, than with lidocaine alone (P<0.001 vs P<0.05, respectively). The onset times of motor blocks were the longest for the median nerve (P<0.05) and the shortest for the musculocutaneous nerve (P<0.001). Neither nervous nor vascular complications occurred. CONCLUSION: This study shows that the nerve block at the humeral canal is an efficient and safe technique. Considering the onset times of nerve blocks, the following sequence for blockade can be recommended: median, ulnar, radial, musculocutaneous, medial (brachial and antebrachial) cutaneous nerves. The selective blockade of the main nerves of the upper limb at the humeral canal can be recommended for surgery of the forearm and the hand in the ambulatory patient.     

Anatomical study of the brachial plexus using surface ultrasound

The aim of this study was to define the anatomy relevant to brachial plexus regional anaesthesia and to identify the extent of variation between individuals. Surface ultrasound examination of the brachial plexus was performed on twenty volunteers. In the axilla there was considerable individual variation in the location of the median, radial and ulnar nerves in relation to the axillary artery. There was often more than one venous structure in this region, which was easily compressed by surface palpation. In the supraclavicular region, neural elements were located inferiorly to the subclavian artery in two volunteers. In one volunteer, a vein was identified between nerve trunks in the interscalene region. These findings indicate that the anatomical variation is considerable, even within the relatively small sample studied. For this reason, use of surface ultrasound may lead to increased success of brachial plexus regional anaesthesia and a decreased risk of intravascular injection.     

Percutaneous electrode guidance using the insulated needle for prelocation of peripheral nerves during axillary plexus blocks

BACKGROUND AND OBJECTIVES: Short reports have noted that percutaneous prelocation is helpful in determining the anatomic course of a peripheral nerve, and, thereby, may serve as a guide for block needle insertion. We prospectively studied percutaneous electrode guidance to assist axillary brachial plexus blocks. METHODS: In 131 consecutive patients, the tip of an insulated needle emitting 5 mA was placed on the skin above and below the axillary artery to obtain a hand motor response characteristic of the median, ulnar, and radial nerves in succession. The current was reduced until all movement had ceased. The needle was then inserted toward the nerve to be blocked, decreasing the intensity from 2 mA to 0.5 mA, so that the same selected motor response was still obtained. The length of the needle inserted was noted, and 1.5% lidocaine was injected. Pain verbal analogic score (VAS) values were noted during both procedures. Complete sensory blockade was evaluated at 30 min. RESULTS: Rates of successful percutaneous electrode guidance were 94.6% for the median nerve, 89.4% for the radial nerve, 88.5% for the ulnar nerve, and 85.5% for all 3 nerves together. A significant correlation was found between the lowest percutaneous current applied and the depth of the nerve stimulated at 0.5 mA. Pain VAS values were significantly lower during percutaneous stimulation than during needle insertion (P <.05). Sensory block for all 3 nerves was noted in 92% of patients. CONCLUSIONS: Percutaneous electrode guidance using the insulated needle enabled clinicians to locate the terminal branches of the plexus in the axilla and appreciate their depth. This method could, therefore, minimize patient discomfort and perhaps the risk of nerve trauma.     

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.     

A comparison of a single-stimulation lateral infraclavicular plexus block with a triple-stimulation axillary block

BACKGROUND AND OBJECTIVES: A single-stimulation infraclavicular brachial plexus block (ICB) is safe and easy to perform, although underused. This technique was compared with a triple-stimulation axillary block (AxB). METHODS: One hundred patients scheduled for hand and forearm surgery were randomly allocated to 2 groups. ICB was performed with the needle inserted above the coracoid process in the upper lateral angle of the infraclavicular fossa and directed vertically until nerve stimulation elicited a distal motor response (median, radial, or ulnar). A single 40-mL bolus of ropivacaine 0.75% was injected. In the AxB group, 3 stimulations were performed to identify median or ulnar, radial, and musculocutaneous nerves, followed by an infiltration near the medial brachial and antebrachial cutaneous nerves. The same 40 mL of ropivacaine 0.75% was injected. Sensory and motor blocks were assessed at 5-minute intervals over 30 minutes. RESULTS: The time to block performance was shorter in the ICB than in the AxB group (2.5 +/- 1.9 minutes v 6.0 +/- 2.8 minutes, P <.001). The success rate (complete block in median, radial, ulnar, musculocutaneous, and medial antebrachial cutaneous nerves) was comparable in the 2 groups (90% v 88% in groups ICB and AxB, respectively). Block extension was comparable, except for a higher rate of block completion in the axillary nerve distribution in group ICB and in the medial brachial cutaneous nerve in group AxB. The onset of each nerve block was comparable except for a faster onset for the musculocutaneous nerve in group AxB (8 +/- 3 v 10 +/- 5 minutes). CONCLUSION: A single shot ICB is equally effective as a triple-nerve stimulation AxB.     

Variant location of the musculocutaneous nerve during axillary nerve block

We present the case of a 56-year-old man who underwent axillary nerve block for a wrist arthroscopy procedure, with real-time ultrasound and peripheral nerve stimulator guidance. The ulnar nerve and radial nerve were located medial and posterior to the brachial artery, respectively. A large complex structure was noted in the position typically occupied by the median nerve. Contact of this structure with the stimulating needle produced strong biceps contraction, and slight adjustment of the needle resulted in forearm pronation. After injection of 10 mL of local anesthetic near this structure, it appeared to consist of two separate components on ultrasound. We believe that these components represented the median and musculocutaneous nerves lying together, lateral to the artery. Radial, median, ulnar, and musculocutaneous nerve block ensued, and wrist arthroscopy was carried out uneventfully. Knowledge of this anatomical variation may improve anesthesiologists' ability to provide effective axillary block.     

Vascularized ulnar nerve graft

The purpose of this article is to describe the indications, anatomy, and harvesting technique of vascularized ulnar nerve graft based on the superior ulnar collateral artery (SUCA) for reconstruction of upper extremity function. The ulnar nerve has an extrinsic blood supply consisting of multiple dominant systems: the SUCA, the inferior ulnar collateral artery, the posterior ulnar recurrent artery, and the ulnar artery. The entire length of the ulnar nerve can survive based on the SUCA and its venae comitantes. The vascularized ulnar nerve graft is used when there is a hopeless prognosis for ulnar nerve repair. This technique may be selected if there is a definite evidence of preganglionic injuries of the C8 and T1 roots in brachial plexus injuries. This technique can be recommended for reconstruction of a large defect of the median or radial nerves in selected cases, such as upper arm replantation.     

A comparison of stimulation patterns in axillary block: part 2

BACKGROUND AND OBJECTIVES: Radial plus musculocutaneous nerve stimulation may have a predominant role in the success of an axillary block, producing more extensive anesthesia of the upper limb than median plus musculocutaneous nerve stimulation. However, no comparison has been made with ulnar plus musculocutaneous nerve stimulation. We compared the extent of both sensory and motor block after ulnar plus musculocutaneous nerve stimulation or radial plus musculocutaneous nerve stimulation. METHODS: Sixty patients were randomly assigned to receive an axillary block using either radial plus musculocutaneous or ulnar plus musculocutaneous nerve stimulation with 40 mL plain 1.5% mepivacaine. Patients were assessed for sensory block by the pinprick method at 5 and 20 minutes. RESULTS: No statistically significant differences were found in the rates of anesthesia at 20 minutes in the cutaneous nerve distributions of the upper limb between radial plus musculocutaneous and ulnar plus musculocutaneous nerve stimulation except for the following nerves: radial (90% and 63.3%, respectively), medial cutaneous of the forearm (83.3% and 100%, respectively), and medial cutaneous of the arm (73.3% and 93.3%, respectively). Global sensory score (minimum: 0; maximum: 12 points) at 20 minutes was significantly higher after radial plus musculocutaneous than after ulnar plus musculocutaneous nerve stimulation: 12 (11-13) and 11 (10-12), respectively. The rates of median nerve blockade were 50% and 53%, respectively. CONCLUSIONS: Radial plus musculocutaneous nerve stimulation produced more extensive anesthesia of the upper limb than did ulnar plus musculocutaneous nerve stimulation. However, there is not an optimal combination of 2 responses in axillary brachial plexus block.     

Axillary plexus block using a peripheral nerve stimulator: single or multiple injections

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.     

The anatomy of the pectoral nerves and their significance in brachial plexus reconstruction

Twenty-nine brachial plexuses from 13 embalmed and 5 fresh cadavers were examined under x3.5 loupe magnification to collect systematic and topographic anatomical data regarding the lateral and medial pectoral nerves. Additionally, nerve biopsy specimens were harvested in 5 fresh cadavers to obtain histomorphometric data. In all dissections the pectoral nerves exited at the trunk level as 3 distinct nerves. The superior pectoral nerve (from the anterior division of the superior trunk) commences just distal to the suprascapular nerve and courses laterally to innervate the lateral clavicular portion of the pectoralis major muscle (PM) with 2 to 4 branches. The middle pectoral nerve (from the anterior division of the middle trunk) courses distally and enters the infraclavicular fossa with 2 constant branches. The superficial branch terminates in the medial clavicular and upper sternal parts of the PM. The deep branch always forms a plexus with the medial pectoral or inferior pectoral nerve (from the anterior division of the inferior trunk), which courses at a right angle around the the lateral thoracic artery. From this plexus several branches terminate in the Pm. The branch to the lower aspect of the PM pierces the pectoralis minor muscle in two thirds of cases, whereas it passes its inferior border to reach the lower aspects of the PM with an average length of 15 cm in one third of cases. Knowledge of the detailed anatomy of the pectoral nerves, as outlined in this study, clarifies the obscure anatomic relationship of the lateral and medial pectoral nerves and allows easy intraoperative location of the medial pectoral nerve at the exit of the lateral thoracic artery. The length of the inferior pectoral nerve, the number of motor axons, and the anatomical proximity of this nerve make it an expendable but powerful source of reinnervation to the musculocutaneous nerve in upper brachial plexus injuries.     

The ulnar nerve as vascularized nerve transplant. Part I: Anatomy: arterial vascular supply

The ulnar nerve is supplied basically by the arteries accompanying it in its various locations: in the axillary section, by a branch of the lateral thoracic artery or directly by the axillary artery; in the upper arm, by branches originating from the collateral ulnar superior artery; in the supracondylar section and in the region of the groove for the ulnar nerve, by branches originating from the anastomosis of the collateral arteries and the posterior branch of the recurrent ulnar artery; and in the forearm, by branches of the recurrent ulnar artery and the ulnar artery. Venous return is by the venae comitantes. Since the ulnar nerve possesses a good arterial supply, it may be used with different techniques as a vascularized nerve transplant in traumatic lesions of the brachial plexus, to repair more important missing nerve paths.     

Continuous axillary brachial plexus block--a clinical and anatomical study

In order to decrease both the failure rate and inadvertent arterial puncture rate that may be associated with continuous axillary brachial plexus block, a new technique of insertion of the catheter in the axilla was studied in 52 patients and in 12 fresh cadavers. With the arm abducted, externally rotated, and flexed at the elbow, an 80-mm long catheter was inserted under the skin at a site located 40-mm below the axilla and medial to the biceps muscle. Injection of lidocaine and bupivacaine produced sensory and motor blockades of the median, radial, ulnar, and musculocutaneous nerves in 98% of the patients. Arterial puncture occurred in one. The catheter was left in situ up to 9 days without complications. In the anatomical study, injection of dye and molding solutions showed that the tip of the catheter lay not in the perivascular sheath, but in a virtual cavity that was very superficial, under the skin, and surrounding the perivascular space. The technique used was safe and had a high success rate. It is particularly useful in patients undergoing long operations and in patients in whom pain would otherwise prevent postoperative physiotherapy of the upper arm.     

二期多组神经移位治疗臂丛神经根性撕脱伤的临床应用和疗效

目的 分析治疗臂丛神经根性撕脱伤的二期手术方法及其效果。方法 2001年8月～2003年4月8例全臂丛神经根性撕脱伤患者，年龄18～38岁。平均伤后6个月内，均应用以下术式治疗。手术步骤：一期手术，膈神经移位至臂丛上干前股，副神经移位至肩胛上神经；健侧C7神经移位至患侧尺神经；二期手术，第4、5、6、7肋间神经移位至桡神经和胸背神经，健侧C7神经经尺神经移位至正中神经。结果 术后8例均获随访，时间为二期术后l3～25个月，平均21个月。所有患者均有不同程度恢复，相应靶肌肉肌力恢复大于或等于M3为有效恢复，肌皮神经有效恢复6例，恢复率为75．0％；肩胛上神经有效恢复3例，恢复率为37．5％；桡神经有效恢复3例，恢复率为37．5％；胸背神经有效恢复6例，恢复率为75．0％；正中神经有效恢复5例，恢复率为62．5％。感觉恢复情况：正中神经感觉4例为S3，3例为S2，1例为S1。结论 二期多组神经移位安全有效，对部分早期臂丛神经损伤并要求缩短手术次数的患者，是一种可选择的方法。