Neuroanatomical relationship between Jingbi and the brachial plexus.

BACKGROUND: This study examined the stratified anatomy of the traditional acupuncture point Jingbi and the neuroanatomical relationship between Jingbi and the brachial plexus, and investigated neural pathways that could be affected by acupuncture stimulation at Jingbi. METHODS: Twelve dissected specimens were used to study the pathway of an acupuncture needle inserted at Jingbi. The stratified anatomy and the neuroanatomical relationship between Jingbi and the brachial plexus were studied. Our samples were grouped by gender and cause of death for comparative analysis. RESULTS: All needles (n = 24, on both sides of a total of 12 cadavers) punctured the anterior scalene muscle medial to the brachial plexus and external jugular vein, lateral to the phrenic nerve and internal jugular vein, and superior to the clavicle and subclavian artery/vein. The depth of needle insertion at Jingbi on the right side of male samples was 28.0 (interquartile range (IQR), 22.5-30.8) mm, which was approximately 8 mm deeper than for female subjects (p < 0.05). The needle was 3.0 (IQR, 2.0-5.0) mm and 7.0 (IQR, 5.5-8.0) mm medial to the brachial plexus on the left and right sides, respectively. CONCLUSION: Deep needle insertion at Jingbi can puncture the anterior scalene muscle. The mechanism of action of acupuncture stimulation at Jingbi might be related to its close relationship with the brachial plexus. Significant differences in needling depth were observed when our samples were grouped by gender. More studies are needed.

A cadaveric study to determine the minimum volume of methylene blue to completely color the nerves of brachial plexus in cats. An update in forelimb and shoulder surgeries.

PURPOSE: To determine the minimum volume of methylene blue (MB) to completely color the brachial plexus (BP) nerves, simulating an effective anesthetic block in cats. METHODS: Fifteen adult male cat cadavers were injected through subscapular approach with volumes of 2, 3, 4, 5 and 6 ml in both forelimbs, for a total of 30 brachial plexus blocks (BPB). After infusions, the specimens were carefully dissected preserving each nervous branch. The measurement of the effective area was indicated by the impregnation of MB. Nerves were divided into four segments from the origin at the spinal level until the insertion into the thoracic limb muscles. The blocks were considered effective only when all the nerves were strongly or totally colored. RESULTS: Volumes of 2, 3 and 4 ml were considered insufficient suggesting a failed block, however, volumes of 5 and 6 ml were associated with a successful block. CONCLUSIONS: The injection of methylene blue, in a volume of 6 ml, completely colored the brachial plexus. At volumes of 5 and 6 ml the brachial plexus blocks were considered a successful regional block, however, volumes of 2, 3 and 4 ml were considered a failed regional block.

A cadaveric study to determine the minimum volume of methylene blue to completely color the nerves of brachial plexus in cats. An update in forelimb and shoulder surgeries

PURPOSE: To determine the minimum volume of methylene blue (MB) to completely color the brachial plexus (BP) nerves, simulating an effective anesthetic block in cats. METHODS: Fifteen adult male cat cadavers were injected through subscapular approach with volumes of 2, 3, 4, 5 and 6 ml in both forelimbs, for a total of 30 brachial plexus blocks (BPB). After infusions, the specimens were carefully dissected preserving each nervous branch. The measurement of the effective area was indicated by the impregnation of MB. Nerves were divided into four segments from the origin at the spinal level until the insertion into the thoracic limb muscles. The blocks were considered effective only when all the nerves were strongly or totally colored. RESULTS: Volumes of 2, 3 and 4 ml were considered insufficient suggesting a failed block, however, volumes of 5 and 6 ml were associated with a successful block. CONCLUSIONS: The injection of methylene blue, in a volume of 6 ml, completely colored the brachial plexus. At volumes of 5 and 6 ml the brachial plexus blocks were considered a successful regional block, however, volumes of 2, 3 and 4 ml were considered a failed regional block. .

Descriptive anatomy of the interscalene triangle and the costoclavicular space and their relationship to thoracic outlet syndrome: a study of 60 cadavers.

OBJECTIVE: Thoracic outlet syndrome classically results from constrictions in 1 or more of 3 specific anatomical locations: the interscalene triangle, costoclavicular space, and coracopectoral tunnel. Magnetic resonance and computed tomographic imaging studies suggest that, of the 3 potential locations for constriction, the costoclavicular space is the most susceptible to compression. This study of human cadavers aims to expand on the descriptive anatomy of the interscalene triangle and associated costoclavicular space. METHODS: The interscalene angle, interscalene triangle base, and costoclavicular space were measured on 120 sides of embalmed human cadavers. Linear distances and angles were measured using a caliper and protractor, respectively. The data were analyzed by calculating the mean, range, and standard deviation. RESULTS: The range for the interscalene base was 0 to 21.0 mm with a mean of 10.7 mm. For the interscalene angle, the range was 4° to 22° with a mean of 11.3°. Measurements for the costoclavicular space ranged from 6 to 30.9 mm with a mean of 13.5 mm. CONCLUSIONS: No significant differences were observed between left and right interscalene triangles or costoclavicular spaces; furthermore, there were no differences between the sexes concerning these 2 locations.

Normative cross-sectional area of the brachial plexus and subclavian artery using ultrasonography.

OBJECTIVE: Ultrasonography has been used to measure the cross-sectional area (CSA) of peripheral nerves, but the CSA of the brachial plexus has not previously been reported. The purpose of this study was to establish a reference range of values for the CSA of the brachial plexus, subclavian artery, and peak systolic velocity (PSV) of the subclavian artery in healthy subjects using ultrasonography. METHODS: Thirty-two asymptomatic subjects (19 men, 13 women) from a chiropractic college with an average age of 29.5 +/- 9.6 participated in the study. The brachial plexus and subclavian artery CSA were measured at 3 locations: interscalene, first rib, and infraclavicular. The PSV of the subclavian artery was measured in both supraclavicular and infraclavicular locations. Each subject was imaged bilaterally. Means and 95% confidence intervals were calculated. Interexaminer reliability was evaluated between 2 examiners on 15 randomly selected subjects. RESULTS: The average CSA for the brachial plexus at the interscalene space, first rib, and infraclavicular location was 0.75 +/- 0.05, 0.96 +/- 0.07, and 0.98 +/- 0.07 cm(2), respectively. The average CSA for the subclavian artery at the same locations was 0.35 +/- 0.03, 0.38 +/- 0.03, 0.35 +/- 0.03 cm(2), respectively. The average subclavian artery PSV in supraclavicular and infraclavicular locations was 98 +/- 8 and 93 +/- 7 cm/s, respectively. The overall interexaminer reliability was poor at 0.39 (0.20-0.55). CONCLUSIONS: This is the first study to obtain normative CSA measurements of the brachial plexus and subclavian artery in multiple locations of the thoracic outlet as well as interexaminer reliability data. These data may be beneficial in future studies designed to assess the brachial plexus and subclavian artery in patients with thoracic outlet syndrome.

High or low current threshold for nerve stimulation for regional anaesthesia.

BACKGROUND: The purpose of this study was to determine whether the application of high stimulation current thresholds (SCT) leads to a distant needle to nerve proximity (NNP) compared with low SCT during nerve localization for regional anaesthesia in pigs. METHODS: A minimal motor response to the stimulation of femoral or brachial plexus nerves in 16 anaesthetized pigs was triggered either by a minimal SCT of a low (0.01-0.3 mA) or a high (0.8-1.0 mA) current in a random order. After eliciting a motor response with a predetermined SCT, synthetic resin was injected via the needle. After postmortem dissection of the injection site, the localization of the resin deposition was determined verifying the final position of the needle tip. Depending on the proximity of resin deposition to the nerve epineurium, the needle tip placement was considered either as a close or a distant NNP. RESULTS: A total of 235 punctures were performed. Ninety-one punctures were carried out with low SCT and 92 with a high SCT. Fifty-two punctures served as a control (1.8-2.0 mA). All injectates following both high or low SCT were considered 'close needle tip to nerve placement', whereas 27 of 52 injectates of the control group appeared distant to nerve epineurium. CONCLUSION: Regardless of the applied SCT, i.e. high or low, all resin deposition was found adjacent to nerve epineurium. These findings suggest that high and low SCT result in equivalent needle tip localization in pigs.

Brachial plexus block with or without ultrasound guidance.

PURPOSE OF REVIEW: Should ultrasound or nerve stimulation be used for brachial plexus blocks? We investigated last year's literature to help answer this question. RECENT FINDINGS: Many of the reports concluded that ultrasound guidance may provide a higher success rate for brachial plexus blocks than guidance by nerve stimulator. However, the studies were not large enough to conclude that ultrasound will reduce the risk of nerve injury, local anesthetic toxicity or pneumothorax. Ultrasound may reveal anatomical variations of importance for performing brachial plexus blocks. For postoperative analgesia, 5 ml of ropivacaine 0.5% has been sufficient for an ultrasound-guided interscalene block. For peroperative anesthesia, as much as 42 ml of a local anesthetic mixture was calculated to be appropriate for an ultrasound-guided supraclavicular method. For the future, we notice that three-dimensional and four-dimensional ultrasound technology may facilitate visualizing the needle, the nerves and the local anesthetic distribution. Impedance measurements may be helpful for nerve blocks not guided by ultrasound. SUMMARY: We think that the literature gives a sufficient basis to recommend the use of ultrasound for guidance of brachial plexus blocks. The potential for ultrasound to improve efficacy and reduce complications of brachial plexus blocks requires larger scaled studies.

Anatomical and experimental studies of brachial plexus, sciatic, and femoral nerve-location using peripheral nerve stimulation in the dog.

OBJECTIVE: To investigate the anatomy of the brachial plexus, sciatic, and femoral nerves for the use of a peripheral nerve-stimulator to perform nerve blocks in dogs. STUDY DESIGN: Prospective experimental trial. ANIMALS: Four canine cadavers and four healthy adult dogs weighing 23 +/- 2.5 kg. METHODS: Phase I: in four canine cadavers, an anatomical study was conducted to evaluate accurate needle-insertion techniques. Phase II: the utility of these techniques, and the value of electrostimulation, were evaluated in four anesthetized dogs in lateral recumbency (medetomidine, 5 microg kg(-1)/ketamine 5 mg kg(-1)) using an electrical stimulator and shielded needles. RESULTS: For the brachial plexus, the needle was inserted cranial to the acromion, medial to the subscapularis muscle, at an angle of approximately 20-30 degrees in relation to a plane vertical to the surface on which the animal was lying, oriented parallel to the long axis of the animal, in a ventro-caudal direction. For the sciatic nerve, the needle was inserted just cranial to the sacrotuberous ligament, through the gluteus superficialis muscle, at an angle of approximately 60 degrees in relation to the horizontal plane, in a ventro-cranial direction, and up to the level of the ischium. For the femoral nerve, the needle was inserted perpendicular to the skin, just cranial to the femoral artery, and directed a little caudally. Using a peripheral nerve-stimulator, all nerves were located, and muscle contractions were elicited at a current of 0.2-0.4 mA. No complications were observed during the procedures. CONCLUSION: Electrostimulation of peripheral nerves is useful in locating the branches of the brachial plexus as well as the sciatic and femoral nerves in dogs. CLINICAL RELEVANCE: Peripheral nerve stimulation increases the reliability of a nerve block when compared with blind needle-insertion.

An ultrasound study of the phrenic nerve in the posterior cervical triangle: implications for the interscalene brachial plexus block.

BACKGROUND AND OBJECTIVES: Concomitant phrenic nerve block frequently occurs after brachial plexus block procedures in the neck and can result in substantial morbidity. In this study we sought to establish the anatomic basis using ultrasound imaging. METHODS: We scanned the neck region of 23 volunteers with high resolution ultrasonography and identified the phrenic nerve in 93.5% of scans. RESULTS: The phrenic nerve was monofascicular with a mean diameter of 0.76 mm. The phrenic nerve position was nearly indistinguishable from the C5 ventral ramus at the level of the cricoid cartilage (mean distance 1.8 mm). Separation between the phrenic nerve and the brachial plexus increased substantially at more caudal levels in the neck. Phrenic nerve identification was confirmed by percutaneous injection of methylene blue followed by open dissection in a cadaver. Furthermore its identity was confirmed by ultrasound-guided transcutaneous nerve stimulation. CONCLUSIONS: This descriptive study found that the phrenic nerve and brachial plexus are within 2 mm of each other at the cricoid cartilage level, with additional 3 mm separation for every cm more caudal in the neck. Clinical trials with imaging guidance are needed to establish whether brachial plexus selective blocks can be consistently achieved above the clavicle.

Ultrasound-guided suprascapular nerve block technique.

BACKGROUND: In this article, we describe a case report of using real-time, high-resolution ultrasound guidance to facilitate blockade of the suprascapular nerve. We describe a case report and technique for using a portable ultrasound scanner (38 mm broadband (13-6 MHz) linear array transducer (SonoSite Micromaxx SonoSite, Inc. 21919 30th Drive SE Bothwell W. A..)) to guide suprascapular nerve block. METHODS: A 44-year old male patient presented with severe, painful osteoarthritis with adhesive capsulitis of his right shoulder. The ultrasound transducer in a transverse orientation was placed over the scapular spine. Moving the transducer cephalad the suprascapular fossa was identified. While imaging the supraspinatus muscle and the bony fossa underneath, the ultrasound transducer was moved laterally (maintaining a transverse transducer orientation) to locate the suprascapular notch. The suprascapular nerve was seen as a round hyperechoic structure at 4 cm depth beneath the transverse scapular ligament in the scapular notch. The nerve had an approximate diameter of 200 mm. Real-time imaging was used to direct injection in the scapular notch. Ultrasound scanning confirmed local anesthetic spread. RESULTS: The patient's pain intensity decreased. Shoulder movement and function improved. These improvements were maintained at 12 weeks. CONCLUSION: Ultrasound guidance does not expose patients and personnel to radiation. It is also less expensive than other imaging modalities. This technique has applications in both acute and chronic pain management.

[Ultrasound in local anaesthesia. Part II: ultrasound-guided blockade of peripheral nerve channels]. / Ultraschall in der Regionalanästhesie. Teil II: Ultraschallunterstützte Blockaden der peripheren Nervenbahnen.

Recent developments in blockade techniques are based on the possibilities offered by modern sonography. With high frequency linear probes, the smallest tissue structures, such as peripheral nerves, in areas close to the surface can be visualised. This is the prerequisite for ultrasound-guided blockade techniques which has now been established for available peripheral blockades. These techniques are basically far superior to all other assist methods of peripheral blockades, because they allow a success rate close to 100%, a short preparation time and a reduction in the use of local anaesthetic agents. Apart from these, one particularly important aspect is that they reduce the risks of local anaesthesia procedures by direct imaging of neighbouring anatomical structures. In this article the theoretical basis of ultrasound techniques and their practical use in local anaesthesia will be presented.

[High continuous axillary-brachial plexus anesthesia. Comparison of a new method with perivascular axillary-brachial plexus anesthesia]. / Die hohe kontinuierliche axilläre Plexus-brachialis-Anaesthesie. Vergleich einer neuen Methode mit der perivaskulären axillären Plexus-brachialis-Anaesthesie.

High axillary brachial plexus anaesthesia was performed in 25 patients. This technique employs simple, straight forward axillary access, and produces an infraclavicular brachial plexus block which is adequate for anaesthesia of the entire arm. The technique and the equipment required are described in the text and illustrated by the figures. Twenty patients who received high axillary brachial plexus anaesthesia were compared with 20 patients who received conventional axillary brachial plexus anaesthesia. The arm anaesthesia attained was classified as being of the analgesic or the anaesthetic stage by pin-prick testing at 4-min intervals, and the motor block, as paretic or the paralytic stage. Five incorrect catheter placements (i.e., 20%) were observed in the group with high axillary brachial plexus anaesthesia; however, they could be revised to produce conventional axillary brachial plexus blocks. Blood mepivacaine level determinations performed over a 90-min period showed that the relatively high dosage used (with average 7.29 gm/kg body weight) did not result in toxic blood levels. This technique involves advancing the catheter 8.3-20 cm (mean 13.9 cm) beyond the puncture site. In 11 cases, it was necessary to overcome resistance when advancing the needle. The site of placement was determined by electrostimulation and cold-temperature-testing. Comparison of both groups revealed that the block is faster and more complete, and the nerves which are usually difficult to block with plexus anaesthesia are anaesthetized better with the high axillary block than with the conventional technique. The anaesthesia of the axillary and musculocutaneous nerves showed an impressive improvement. Whereas the usually difficult block of the radial nerve in the hand was greatly improved, the median and ulnar nerves were blocked equally well using either method. The only complication that occurred was an intravenous catheter placement, which was diagnosed and corrected. No other early or late complications were observed following the use of this technique in a large group of patients. This new technique is simple and easy to master.

La lesión obstétrica del plexo braquial / Obstetrical braquial plexus injury

El motivo de esta comunicación es presentar el estudio anatomopatológico de la lesion obstetrica del plexo braquial y su correspondiente correlación clínica. Los hallazgos a los que se hace mención corresponden a los obtenidos mediante cirugia plexual directa y examenes que comprenden: electroestimulacion y registro de potenciales evocados intraoperatoriamente, y microscopía convencional y electronica de las estructuras biopsiadas, con un seguimiento postoperatorio mínimo de 3 años (resumen truncado)

Acupuncture points of the brachial plexus.

This publication is the third of a total of six papers intended to name acupuncture points following the anatomic nomenclatures. In the first publication, acupuncture points in the head are named using terminal branches of the trigeminal nerve and the muscles of facial expression. In the second publication, acupuncture points in the neck are named using the cutaneous nerves of the cervical plexus and neuromuscular attachments formed by the spinal accessory nerve on the trapezius muscle. In this third publication, acupuncture points existing on the upper limbs are described following the terminal branches of the brachial plexus.

Brachial plexus injuries.

There can be few more distressing situations than when a young man sustains a total and irreversible paralysis in his dominant arm. Not only is he left with a useless and anaesthetic limb, but in a high proportion of cases suffers intractable pain. This article will discuss the diagnosis and management of such injuries.

[Brachial plexus block anesthesia in the upper limb surgery (author's transl)]. / Blocs du plexus brachial dans la chirurgie du membre supérieur. A propos de 139 cas.

This work, during a period of 2 years, has been carried out on 139 brachial plexus block anesthesias out of which --92 through axillary approach--47 through supraclavicular approach. Our failure rate was--6,5 p. cent in the case of the axillary block--10,6 p. cent in the case of the supraclavicular block. This gives us a failure average of 7,9 p. cent. Depending on the duration of the operation we have been using three kinds of drugs, always without adrelanine--Lidocaïne . . . 2 p. cent--Mepivacaïne . . . 2 p. cent--Bupivacaïne . . . 0,5 p. cent. We finally adopted two mixtures based on lidocaïne together with mepivacaine or bupivacaine keeping the same concentration but reducing to half the doses of these last two drugs. In our work, we have not noted any complication, and we think that a locoregional anesthesia, should, as far as it is possible, be used as a substitute for general anesthesia instead of being used when general anesthesia is contra-indicated.