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

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 ).

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.

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.