Clinical sonopathology for the regional anesthesiologist: part 1: vascular and neural

Origin variations and brachial plexus relationship of the dorsal scapular artery

The dorsal scapular artery can either be a direct branch of the subclavian artery or a branch of the transverse cervical artery. Origin variation is related to its relationship with the brachial plexus. Anatomical dissection was performed on 79 sides of 41 formalin-embalmed cadavers in Taiwan. The origin of the dorsal scapular artery and the variations of its brachial plexus relationship were scrutinized and analyzed. Results showed that the dorsal scapular artery originated most frequently from the transverse cervical artery (48%), followed by the direct branch from the third part (25%) and the second part (22%) of the subclavian artery and from the axillary artery (5%). Only 3% of the dorsal scapular artery passed through the brachial plexus if its origin was the transverse cervical artery. However, 100% and 75% of the dorsal scapular artery passed through the brachial plexus when they were direct branches of the second and the third part of the subclavian artery, respectively. Suprascapular arteries were also found to pass through the brachial plexus when they were direct branches from the subclavian artery, but all passed over or under the brachial plexus if they originated from the thyrocervical trunk or transverse cervical artery. Variations in the origin and course of arteries around the brachial plexus are of immense value not only to the basic anatomical knowledge but also to clinical practices such as supraclavicular brachial plexus block and head and neck reconstruction with pedicled or free flaps.

Ultrasound-guided interventional procedures for chronic pain management

Ultrasonography has multiple advantages over traditional radiologic imaging modalities when used for interventional procedures. It allows improved visualization of the anatomy while avoiding ionizing radiation and risks associated with contrast use. It has proved superiority at accuracy of delivery and procedural effectiveness over blind procedures when used in association with interventional pain procedures. Although limited in its ability to see through bony structures, ultrasound has utility in visualizing soft tissues and vascular structures in anatomic regions of interest resulting in increased use for posterior neuraxial, periaxial, peripheral nerve and joint-related structures. Current evidence for use in these settings is presented here. In some cases, optimal utility may be improved by combining ultrasonography with other imaging modalities.

Origin of the dorsal scapular artery and its relation to the brachial plexus in Thais

We investigated the variations of the origin of the dorsal scapular artery (DSA) and its relation to the brachial plexus in 252 sides of the posterior cervical triangles of Thais. The origin of this artery on each part of the subclavian artery or other arterial branches was examined with special reference to their course in relation to the brachial plexus. The results show that the DSA originated from three sites; most commonly from the transverse cervical artery (69%) followed by the direct branching from the second (2.8%) or the third part (28.2%) of the subclavian artery. When the DSA was branched from the transverse cervical artery, its course was always posterior or above the brachial plexus. When the DSA arose from the second or the third part of the subclavian artery, it always ran in the branches of the brachial plexus in various sites. The most frequent course was to pass between the upper and middle trunks of the brachial plexus (63.2%). Other courses were far less frequent and found to pass between the anterior division of the upper trunk and the middle trunk of brachial plexus or between the roots of C8 and T1 with the frequency of 1.3 and 2.6%, respectively.

The American Society of Regional Anesthesia and Pain Medicine, the European Society of Regional Anaesthesia and Pain Therapy, and the Asian Australasian Federation of Pain Societies Joint Committee recommendations for education and training in ultrasound-guided interventional pain procedures

The use of ultrasound in pain medicine for interventional axial, nonaxial, and musculoskeletal pain procedures is rapidly evolving and growing. Because of the lack of specialty-specific guidelines for ultrasonography in pain medicine, an international collaborative effort consisting of members of the Special Interest Group on Ultrasonography in Pain Medicine from the American Society of Regional Anesthesia and Pain Medicine, the European Society of Regional Anaesthesia and Pain Therapy, and the Asian Australasian Federation of Pain Societies developed the following recommendations for education and training in ultrasound-guided interventional pain procedures. The purpose of these recommendations is to define the required skills for performing ultrasound-guided pain procedures, the processes for appropriate education, and training and quality improvement. Training algorithms are outlined for practice- and fellowship-based pathways. The previously published American Society of Regional Anesthesia and Pain Medicine and European Society of Regional Anaesthesia and Pain Therapy education and teaching recommendations for ultrasound-guided regional anesthesia served as a foundation for the pain medicine recommendations. Although the decision to grant ultrasound privileges occurs at the institutional level, the committee recommends that the training guidelines outlined in this document serve as the foundation for educational training and the advancement of the practice of ultrasonography in pain medicine.

Ultrasound: Basic understanding and learning the language

Ultrasound (US) use has rapidly entered the field of acute pain medicine and regional anesthesia and interventional pain medicine over the last decade, and it may even become the standard of practice. The advantages of US guidance over conventional techniques include the ability to both view the targeted structure and visualize, in real time, the distribution of the injected medication, and the capacity to control its distribution by readjusting the needle position, if needed. US guidance should plausibly improve the success rate of the procedures, their safety and speed. This article provides basic information on musculoskeletal US techniques, with an emphasis on the principles and practical aspects. We stress that for the best use of US, one should venture beyond the “pattern recognition” mode to the more advanced systematic approach and use US as a tool to visualize structures beyond the skin (sonoanatomy mode). We discuss the sonographic appearance of different tissues, introduce the reader to commonly used US-related terminology, cover basic machine “knobology” and fundamentals of US probe selection and manipulation. At the end, we discuss US-guided needle advancement. We only briefly touch on topics dealing with physics, artifacts, or sonopathology, which are available elsewhere in the medical literature.

Recognition of an incidental abscess and a hematoma during ultrasound-guided femoral nerve block

Ultrasound guidance for femoral nerve blockade allows visualization of normal and abnormal anatomy. Two cases of femoral nerve blockade under ultrasound guidance are presented where a major perineural pathologic lesion was incidentally revealed. These pathologic lesions, an abscess and a hematoma, resulted in significant adaptations in clinical care and have not been reported previously. We review and discuss incidental pathologic lesions that can be found in the femoral region. Identification of these 2 pathologic lesions facilitated our perioperative management strategies in two separate cases.

Ultrasound-guided regional anesthesia for peripheral nerve blocks: an evidence-based outcome review

Ultrasound-guided regional anesthesia (UGRA) has increased in popularity over the past 5 years. This interest is reflected by the plethora of publications devoted to technique development, as well as randomized and controlled trials. Despite the excitement around ultrasonography, skeptics argue that there is a lack of evidence-based medicine to support the unequivocal adoption of UGRA as a "standard of care." This article summarizes and critically assesses current data comparing traditional approaches to localizing nerves with those that use ultrasound guidance. In addition, the potential benefits of UGRA that go beyond current information available from comparative studies are explored.

Does ultrasound-guided lidocaine injection improve local anaesthesia before femoral artery catheterization?

AIM

To present the results of a prospective, randomized, single-centre study investigating local anaesthesia before percutaneous common femoral artery (CFA) puncture and catheterization with the use of ultrasound-guided injection of lidocaine versus standard infiltration by manual palpation.

MATERIALS AND METHODS

Patients scheduled to undergo diagnostic or therapeutic transfemoral catheter-based procedures gave informed consent and were randomized in two groups. In the first arm local anaesthesia with lidocaine hydrochloride 1% was performed under ultrasound guidance (group U/S), while in the second arm the standard method of manual artery palpation was applied (group M). In both groups, subsequent CFA catheterization was achieved under ultrasound guidance. The primary study endpoint was peri-procedural pain level evaluated with a visual-analogue scale (VAS score 0-10).

RESULTS

Between January 2009 and 2010, 200 patients (161 men, mean age 63±12 years) were equally assigned to each group without any significant differences in baseline demographics. Patients in group U/S experienced significantly less pain during CFA catheterization in comparison with group M with a difference of three points in mean VAS score reported (1.6±1.6 versus 4.6±1.9, p<0.0001). In addition, significantly less volume of lidocaine was used in group U/S compared to group M (16±2.7 versus 19±0.8ml, p<0.001).Total vascular access time was similar in both groups (4.4±1.3 versus 4.5±1.3min). Overall complications included two small groin haematomas in each group.

CONCLUSION

Ultrasound-guided local anaesthesia of the CFA prior to percutaneous transcatheter procedures is safe and achieves superior levels of analgesia with minimal patient pain and discomfort compared to the standard method of manual palpation.

Musculoskeletal sonopathology and ultrasound-guided regional anesthesia

The use of real-time ultrasound guidance has revolutionized the practice of regional anesthesia. Ultrasound is rapidly becoming the technique of choice for nerve blockade due to increased success rates, faster onset, and potentially improved safety. In the course of ultrasound-guided regional anesthesia, unexpected pathology may be encountered. Such anomalous or pathological findings may alter the choice of nerve block and occasionally affect surgical management. This case series presents a variety of musculoskeletal conditions that may be encountered during ultrasound-guided regional anesthesia practice.