Background and objectivesUltrasonography of the brachial plexus (BP) has been described but there are limited data on visualization of the T1 ventral ramus and the inferior trunk. This prospective observational study aimed to evaluate a high definition ultrasound imaging technique to systematically identify the individual elements of the BP above the clavicle.MethodsFive healthy young volunteers underwent high definition ultrasound imaging of the BP above the clavicle. The ultrasound scan sequence (transverse oblique scan) commenced at the supraclavicular fossa after which the transducer was slowly swept cranially to the upper part of the interscalene groove and then in the reverse direction to the supraclavicular fossa. The unique sonomorphology of the C7 transverse process was used as the key anatomic landmark to identify the individual elements of the BP in the recorded sonograms.ResultsThe neural elements of the BP that were identified in all volunteers included the ventral rami of C5–T1, the three trunks, divisions of the superior trunk, and formation of the inferior trunk (C8–T1). The C6 ventral ramus exhibited echogenic internal septation with a split (bifid) appearance in four of the five volunteers. In three of the four volunteers with a bifid C6 ventral ramus, the C7 ventral ramus was also bifid.ConclusionWe have demonstrated that it is feasible to accurately identify majority of the main components of the BP above the clavicle, including the T1 ventral ramus and the formation of the inferior trunk, using high definition ultrasound imaging.Trial registration numberChiCTR1900021749.

Purpose: Thoracic paravertebral block (TPVB), in conjunction with intravenous sedation, is reported to provide surgical anesthesia for primary breast cancer surgery (PBCS). Although ultrasound-guided (USG) TPVB has been described, there are no reports of USG multilevel TPVB for surgical anesthesia during PBCS. The aim of this prospective observational study was to determine the feasibility of performing USG multilevel TPVB, at the T1-T6 vertebral levels (6m-TPVB), and to evaluate its efficacy in providing surgical anesthesia for PBCS. Patients and Methods: Twenty-five female patients undergoing PBCS received an USG 6m-TPVB for surgical anesthesia. Four milliliters of ropivacaine 0.5% (with epinephrine 1:200,000) was injected at each vertebral level. Dexmedetomidine infusion (0.1-0.5 µg.kg −1 .h −1) was used for conscious sedation. Success of the block, for surgical anesthesia, was defined as being able to complete the PBCS without having to resort to rescue analgesia or convert to GA. Results: The USG 6m-TPVB was successfully performed on all 25 patients but it was effective as the sole anesthetic in only 20% (5/25) of patients. The remaining 80% (20/25) reported pain during separation of the breast from the pectoralis major muscle and its fascia. Surgery was successfully completed using small doses of intravenous ketamine (mean total dose, 38.0±20.5 mg) as supplementary analgesia. Conclusion: USG 6m-TPVB is technically feasible but does not consistently provide complete surgical anesthesia for PBCS that involves surgical dissection on the pectoralis major muscle and its fascia. Our data suggest that the pectoral nerves, which are not affected by a 6m-TPVB, are involved with afferent nociception.

BACKGROUND Selectively locating and blocking the individual trunks of the brachial plexus with small volumes of local anaesthetic, a selective trunk block (SeTB), may produce anaesthesia of the entire upper extremity except for the T2 dermatome.OBJECTIVE This study aimed to evaluate the effects of an ultrasound-guided (USG) SeTB on ipsilateral sensorimotor block dynamics, hemidiaphragmatic function, and efficacy as an all-purpose regional anaesthetic technique for upper extremity surgery.DESIGN Prospective cohort study.

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