High definition ultrasound imaging of the individual elements of the brachial plexus above the clavicle

Diaphragm-sparing efficacy of subparaneural upper trunk block for arthroscopic shoulder surgery: A randomised controlled trial

BACKGROUND

Inter-scalene block (ISB) is associated with an inevitable risk of hemi-diaphragmatic paresis (HDP). To reduce the risk of HDP, an upper trunk block (UTB) has been proposed at the brachial plexus division level.

OBJECTIVE

We hypothesised that UTB would be associated with a lower incidence of HDP than ISB while providing sufficient analgesia following arthroscopic shoulder surgery.

DESIGN

Randomised controlled trial.

SETTING

A tertiary teaching hospital.

PATIENTS

Seventy patients aged 20 to 80 years undergoing arthroscopic rotator cuff repair.

INTERVENTION

Ultrasound-guided ISB or UTB was performed with 5 ml 0.75% ropivacaine.

MAIN OUTCOME MEASURES

The primary outcome was the incidence of complete HDP, assessed by diaphragm excursion using ultrasound, defined as a decrease to 25% or less of baseline or occurrence of paradoxical movement. Postoperative pulmonary function change, pain scores, opioid consumption and pain-related outcomes were the secondary outcomes.

RESULTS

The UTB group had a significantly lower incidence of complete HDP than the ISB group [5.9% (2/34) vs. 41.7% (15/36); absolute difference, 35.8%; 95% confidence interval (CI), 17.8 to 53.7%; P < 0.001]. The postblockade decline in pulmonary function was more pronounced in the ISB group than that in the UTB group. The pain score at 1 h postoperatively was not significantly different between the groups (ISB vs. UTB group: median 0 vs. 1; median difference, -1; 95% CI, -2 to 0.5). No significant difference was observed in any other secondary outcomes.

CONCLUSION

UTB was associated with a lower incidence of HDP compared with ISB while providing excellent analgesia in arthroscopic shoulder surgery.

TRIAL REGISTRATION

Clinical Trial Registry of Korea (https://cris.nih.go.kr) identifier: KCT0007002.

IRB NUMBER

Chungnam National University Hospital Institutional Review Board No. 2021-12-069.

Continuous Superior Trunk Block versus Single-Shot Superior Trunk Block with Intravenous Dexmedetomidine for Postoperative Analgesia in Arthroscopic Shoulder Surgery: A Prospective Randomized Controlled Trial

Background/Objectives: Intravenous dexmedetomidine (DEX) can increase the analgesia duration of peripheral nerve block; however, its effect in combination with superior trunk block (STB) remains unclear. We examined whether combining single-shot STB (SSTB) with intravenous DEX would provide noninferior postoperative analgesia comparable to that provided by continuous STB (CSTB). Methods: Ninety-two patients scheduled for elective arthroscopic rotator cuff repair were enrolled in this prospective randomized trial. Patients were randomly assigned to the CSTB or SSTB + DEX group. Postoperatively, each CSTB group patient received 15 mL of 0.5% ropivacaine and a continuous 0.2% ropivacaine infusion. Each SSTB group patient received a 15 mL postoperative bolus injection of 0.5% ropivacaine. DEX was administered at 2 mcg/kg for 30 min post anesthesia, then maintained at 0.5 mcg/kg/h till surgery ended. Pain scores were investigated every 12 h for 48 h post operation, with evaluation of rebound pain incidence and opioid consumption. Results: The SSTB + DEX group had significantly higher median pain scores at 12 h post operation (resting pain, 8.0 vs. 3.0; movement pain, 8.0 vs. 5.0) and a higher incidence of rebound pain (56% vs. 20%) than the CSTB group. However, no significant between-group differences were observed in pain scores postoperatively at 24, 36, or 48 h. The CSTB group required less opioids and fewer rescue analgesics within 12-24 h post operation than the SSTB + DEX group. Conclusions: Compared with CSTB, SSTB + DEX required additional adjuvant or multimodal analgesics to reduce the risk and intensity of postoperative rebound pain in patients who underwent arthroscopic rotator cuff repair.

Effect of local anesthetic volume (20 vs. 40 ml) on the analgesic efficacy of costoclavicular block in arthroscopic shoulder surgery: a randomized controlled trial

BACKGROUND

Among the various diaphragm-sparing alternatives to interscalene block, costoclavicular block (CCB) demonstrated a low hemidiaphragmatic paresis (HDP) occurrence but an inconsistent analgesic effect in arthroscopic shoulder surgery. We hypothesized that a larger volume of local anesthetic for CCB could provide sufficient analgesia by achieving sufficient supraclavicular spreading.

METHODS

Sixty patients scheduled for arthroscopic rotator cuff repair were randomly assigned to receive CCB using one of two volumes of local anesthetic (CCB20, 0.75% ropivacaine 20 ml; CCB40, 0.375% ropivacaine 40 ml). The primary outcome was the rate of complete analgesia (0 on the numeric rating scale of pain) at 1 h postoperatively. The secondary outcomes included a sonographic assessment of local anesthetic spread, diaphragmatic function, pulmonary function, postoperative opioid use, and other pain-related experiences within 24 h postoperatively.

RESULTS

The rates of complete analgesia were not significantly different (23.3% [7/30] and 33.3% [10/30] in the CCB20 and CCB40 groups, respectively; risk difference 10%, 95% CI [-13, 32], P = 0.567). There were no significant differences in other pain-related outcomes. Among the clinical factors considered, the only factor significantly associated with postoperative pain was the sonographic observation of supraclavicular spreading. There were no significant differences in the incidence of HDP and the change in pulmonary function between the two groups.

CONCLUSIONS

Using 40 ml of local anesthetic does not guarantee supraclavicular spread during CCB. Moreover, it does not result in a higher rate of complete analgesia compared to using 20 ml of local anesthetic in arthroscopic shoulder surgery.

Optimal view detection for ultrasound-guided supraclavicular block using deep learning approaches

Successful ultrasound-guided supraclavicular block (SCB) requires the understanding of sonoanatomy and identification of the optimal view. Segmentation using a convolutional neural network (CNN) is limited in clearly determining the optimal view. The present study describes the development of a computer-aided diagnosis (CADx) system using a CNN that can determine the optimal view for complete SCB in real time. The aim of this study was the development of computer-aided diagnosis system that aid non-expert to determine the optimal view for complete supraclavicular block in real time. Ultrasound videos were retrospectively collected from 881 patients to develop the CADx system (600 to the training and validation set and 281 to the test set). The CADx system included classification and segmentation approaches, with Residual neural network (ResNet) and U-Net, respectively, applied as backbone networks. In the classification approach, an ablation study was performed to determine the optimal architecture and improve the performance of the model. In the segmentation approach, a cascade structure, in which U-Net is connected to ResNet, was implemented. The performance of the two approaches was evaluated based on a confusion matrix. Using the classification approach, ResNet34 and gated recurrent units with augmentation showed the highest performance, with average accuracy 0.901, precision 0.613, recall 0.757, f1-score 0.677 and AUROC 0.936. Using the segmentation approach, U-Net combined with ResNet34 and augmentation showed poorer performance than the classification approach. The CADx system described in this study showed high performance in determining the optimal view for SCB. This system could be expanded to include many anatomical regions and may have potential to aid clinicians in real-time settings.Trial registration The protocol was registered with the Clinical Trial Registry of Korea (KCT0005822, https://cris.nih.go.kr ).

Proposal of a Route Map for Cervical Spinal Ultrasonography: A Simple and Clear Learning Tool for Beginners

Spinal ultrasonography has increasingly been used to image axial structures from the cervical to sacral region in recent years. In this work, we propose a comprehensive, systematic cervical scanning protocol that we refined as a route map, especially for beginners, to facilitate teaching, learning, diagnosis, and treatment in clinical pain practice. As a simple and clear tool to demonstrate the scanning protocol, the route map is delineated with rectangles, lines, and arrows. The rectangles represent the positions of the transducer, the arrows indicate route directions, and the lines show the routes of transducer movement. In this article, we describe cervical spinal ultrasonography to illustrate the route map interpretation, scanning protocol and target anatomical structures in detail. We believe that this comprehensive, clear, systematic, and portable route map will be beneficial for inexperienced pain clinicians and ultrasound beginners.

Efficacy of intertruncal and corner-pocket approaches of ultrasound-guided supraclavicular block in terms of ulnar nerve blockade: A randomised controlled study

Background and Aims

The incidence of ulnar nerve sparing has declined with the corner-pocket approach of the supraclavicular block (SCB), however, it continues to persist. A recent technique of SCB, the intertruncal approach, separately blocks each trunk of the brachial plexus. Thus, we hypothesised that the intertruncal approach results in a complete ulnar nerve blockade.

Methods

Eighty-eight patients were randomised to undergo SCB using an ultrasound (USG)-guided corner-pocket or intertruncal approach and were compared primarily regarding the complete sensory and motor blockade of the ulnar nerve and all four nerves (ulnar, radial, median and musculocutaneous nerves) at 15 min. Secondary objectives included time required for block performance, patient discomfort score, time to readiness for surgery and duration of sensory blockade of the ulnar nerve. Continous data were compared using an independent t-test, and categorical data were compared using the Chi-square test.

Results

The proportion of participants with complete sensory (30/44 vs. 14/44, P < 0.001) and complete motor (22/44 vs. 7/44, P < 0.001) blocks in the ulnar nerve and all four nerves at 15 min was significantly higher in the intertruncal group. Block performance time and patient discomfort score were higher in the intertruncal group (P < 0.001). The total duration of sensory blockade in the ulnar nerve was more in the corner-pocket group (P < 0.001).

Conclusion

USG-guided intertruncal approach is superior to the corner-pocket approach of SCB regarding a complete ulnar nerve blockade.

A new anatomical brachial plexus variation during interscalene block

We aimed to present our anesthetic management for an ultrasound-guided (USG) interscalene block in the presence of a new brachial plexus variation in a 59-year-old male patient underwent shoulder arthroscopy. An accessory muscle between the anterior scalene (ASM) and middle scalene muscle (MSM) was viewed via ultrasound. When four roots that the accessory muscle separated into two groups, which should be normally present between the ASM and MSM were displayed, we decided to use nerve stimulator to perform block. The contraction response from the deltoid muscle group from both root groups was regarded as a possible new brachial plexus variation in the C5 nerve root. For interscalene block, 30 ml of 0.375% bupivacaine was used via multi-injection. We confirmed this new brachial plexus variation with magnetic resonance neurography for the first time in a patient. Interscalene block should be definitely performed under USG and when a new anatomical variation is suspected, roots should be separated with a nerve stimulator to increase the success of the block.

Comparison of the anesthesia effect of ultrasound-guided middle and low interscalene brachial plexus block: a randomized, controlled, non-inferiority trial

BACKGROUND

Ultrasound-guided low interscalene brachial plexus block (LISB) can provide satisfactory anesthesia for surgery at or below the elbow. However, the anesthesia effect of ultrasound-guided middle interscalene brachial plexus block (MISB) has not been fully investigated. We hypothesized that MISB provides a non-inferior anesthesia effect to LISB for surgery at or below the elbow.

METHODS

A total of 82 patients with ASA I-III (18-65 years) scheduled for elective surgery at or below the elbow were randomized to the MISB group or the LISB group equally, located 1/2 or 2/3 of the caudal distance from C6 to the clavicle. Both groups were administered 15 mL 0.5% ropivacaine at the lower part of the brachial plexus with the first injection and equivalent volume at the upper part with the second injection.

RESULTS

For the primary outcome, 92.3% in the MISB group experienced successful anesthesia compared to 94.6% in the LISB group [difference: -2.3%, 95% confidence interval (CI) -13.4% to 8.8%], exceeding the predefined non-inferiority margin -15%. For the secondary outcomes, the incidence of pleura suppression for the first injection (7.7% vs. 45.9%, P < 0.001) and the time to perform the block (9.9 ± 1.3 vs. 10.7 ± 1.3 min, P = 0.006) were significantly less in MISB compared to LISB. No significant differences were observed in the consumption of perioperative rescue analgesics, VAS score, and adverse events within the two groups.

CONCLUSIONS

MISB provides a non-inferior anesthesia effect to LISB for surgery at or below the elbow.

TRIAL REGISTRATION

Chinese Clinical Trial Register (identifier: ChiCTR2100054196).

Ultrasound-guided selective trunk block: Evaluation of ipsilateral sensorimotor block dynamics, hemidiaphragmatic function and efficacy for upper extremity surgery. A single-centre cohort study

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.

SETTING

Single-centre, university hospital in Hong Kong, China from February 2021 to July 2021.

PATIENTS

Thirty patients (aged 53.2 ± 14.8 years and BMI 23.8 ± 3.6 kg m - 2 ), ASA physical status I to III, scheduled for upper extremity surgery under a brachial plexus block.

INTERVENTIONS

USG SeTB with 25 ml (7, 8 and 10 ml to the superior, middle and inferior trunks, respectively) of a 1 : 1 mixture of 2% lidocaine with 1 : 200 000 epinephrine and 0.5% levobupivacaine.

MAIN OUTCOME MEASURES

Ipsilateral sensorimotor blockade of the suprascapular (only motor), axillary, radial, ulnar, median and musculocutaneous nerves were assessed at regular intervals for 45 min. Ipsilateral hemidiaphragmatic excursion was also measured, at 30 min after the SeTB, using M-mode ultrasound. The SeTB was considered a success if it was possible to complete surgery without any rescue analgesia or conversion to general anaesthesia.

RESULTS

Complete motor blockade of the suprascapular nerve was achieved in median [range] 5 [5 to 15] min. Complete sensory and motor blockade were achieved in all the other 5 nerves in 17.5 [10 to 30] and 15 [10 to 30] min respectively. The SeTB was successful in 93% and ipsilateral hemidiaphragmatic paresis (HDP) was present in 82%, of patients.

CONCLUSION

SeTB produces sensorimotor blockade of the entire upper extremity, causes ipsilateral HDP, and is effective as the sole anaesthetic for surgery from the proximal humerus to the hand.

TRIAL REGISTRION

ClinicalTrials.gov, Trial Registration No: NCT04752410, Date submitted for Registration: 09 February 2021, Date first posted: 12 February 2021, Dates of patient enrolment: 19 February 2021 to 27 July 2021 ( https://clinicaltrials.gov/ct2/show/NCT04752410 ).

Ultrasound-guided selective trunk block (SeTB): a cadaver anatomic study to evaluate the spread of dye after a simulated injection

BACKGROUND AND OBJECTIVES

Recent reports suggest that a selective trunk block (SeTB) can produce sensorimotor blockade of the entire upper extremity, except for the T2 dermatome. There are no data demonstrating the anatomic mechanism of SeTB. This cadaver study aimed to evaluate the spread of an injectate after a simulated ultrasound-guided (USG) SeTB.

METHODS

USG SeTB (n=7) was performed on both sides of the neck in four adult human cadavers with 25 mL of 0.1% methylene blue dye. Anatomic dissection was performed to document staining (deep, faint, and no stain) of the various elements of the brachial plexus from the level of the roots to the cords, including the phrenic, dorsal scapular, and long thoracic nerves. Only structures that were deeply stained were defined as being affected by the SeTB.

RESULTS

All the trunks and divisions of the brachial plexus, as well as the ventral rami of C5-C7 and suprascapular nerve, were deeply stained in all (100%) the simulated injections. The ventral rami of C8 and T1 (86%), dorsal scapular and long thoracic nerve (71%), and the phrenic nerve (57%) were also deeply stained in a substantial number of the injections.

CONCLUSION

This cadaver study demonstrates that an USG SeTB consistently affects all the trunks and divisions of the brachial plexus, as well as the suprascapular nerve. This study also establishes that SeTB may not be phrenic nerve sparing. Future research to evaluate the safety and efficacy of SeTB as an all-purpose brachial plexus block technique for upper extremity surgery is warranted.

TRIAL REGISTRATION NUMBER

Registered at https://www.thaiclinicaltrials.org on December 13, 2021 under the trial registration number TCTR20211213005.

Comparison of the ulnar nerve blockade between intertruncal and corner pocket approaches for supraclavicular block: a randomized controlled trial

Background

The corner pocket (CP) approach for supraclavicular block (SCB) prevents ulnar nerve (UN) sparing due to needle proximity to the lower trunk. Improved ultrasound resolution has suggested that the intertruncal (IT) approach is a suitable alternative method. We compared efficiency of these two approaches on the UN blockade.

Methods

Sixty patients were randomized to undergo SCB using the ultrasound-guided CP or IT approach. For lower trunk blockade, 10 ml of local anesthetic agents (1 : 1 mixture of 0.75% ropivacaine and 1% lidocaine) were injected in the CP (CP approach) or between the lower and middle trunks (IT approach). Additional 15 ml was injected identically to block the middle and upper trunks in both groups. Sensory and motor blockade was evaluated after intervention.

Results

Complete sensory blockade (75.9% [22/29] vs. 43.3% [13/30], P = 0.023) and complete motor blockade (82.8% [24/29] vs. 50.0% [15/30], P = 0.017) of the UN at 15 min after SCB were significantly more frequent in the IT than in the CP group. Sensory block onset time of the UN was significantly shorter in the IT compared to the CP group (15.0 [10.0, 15.0] min vs. 20.0 [15.0, 20.0] min, P = 0.012).

Conclusions

The IT approach provided a more rapid onset of UN blockade than the CP approach. These results suggest that the IT approach is a suitable alternative to the CP approach and can provide faster surgical readiness.

Ultrasound-Guided Selective Trunk Block to Produce Surgical Anesthesia of the Whole Upper Extremity: A Case Report

None of the classical brachial plexus block techniques can reliably produce surgical anesthesia of the whole upper extremity that is from shoulder to hand. We describe ultrasound-guided "selective trunk block" (SeTB) that was successfully used to produce surgical anesthesia of the whole ipsilateral upper extremity in a patient undergoing intramedullary nailing of the humerus for a pathological fracture. The 3 trunks of the brachial plexus were individually identified and selectively blocked with 2 separate injections. We conclude that SeTB is a viable option when surgical anesthesia of the whole upper extremity, except for the intercostobrachial nerve (T2) territory, is being considered.