Nerve Block for Pain Relief During Arthroscopic Rotator Cuff Repair

Convolutional neural network for brachial plexus segmentation at the interscalene level

BACKGROUND

Regional anesthesia with ultrasound-guided brachial plexus block is widely used for patients undergoing shoulder and upper limb surgery, but needle misplacement can result in complications. The purpose of this study was to develop and validate a convolutional neural network (CNN) model for segmentation of the brachial plexus at the interscalene level.

METHODS

This prospective study included patients who underwent ultrasound-guided brachial plexus block in the Anesthesiology Department of Beijing Jishuitan Hospital between October 2019 and June 2022. A Unet semantic segmentation model was developed to train the CNN to identify the brachial plexus features in the ultrasound images. The degree of overlap between the predicted segmentation and ground truth segmentation (manually drawn by experienced clinicians) was evaluated by calculation of the Dice index and Jaccard index.

RESULTS

The final analysis included 502 images from 127 patients aged 41 ± 14 years-old (72 men, 56.7%). The mean Dice index was 0.748 ± 0.190, which was extremely close to the threshold level of 0.75 for good overlap between the predicted and ground truth segregations. The Jaccard index was 0.630 ± 0.213, which exceeded the threshold value of 0.5 for a good overlap.

CONCLUSION

The CNN performed well at segregating the brachial plexus at the interscalene level. Further development could allow the CNN to be used to facilitate real-time identification of the brachial plexus during interscalene block administration.

CLINICAL TRIAL REGISTRATION

The trial was registered prior to patient enrollment at the Chinese Clinical Trial Registry (ChiCTR2200055591), the site url is https://www.chictr.org.cn/ . The date of trial registration and patient enrollment is 14/01/2022.

Sciatic Nerve Block Combined with Flurbiprofen Inhibits Spinal Cord Inflammation and Improves Postoperative Pain in Rats with Plantar Incision

Background and Purpose

Peripheral nerve block is often used to relieve postoperative pain. But the effect of nerve block on inflammatory response is not fully understood. Spinal cord is the primary center of pain processing. This study is to investigate the effect of single sciatic nerve block on the inflammatory response of the spinal cord in rats with plantar incision and the combined effect with flurbiprofen.

Methods

The plantar incision was used to establish a postoperative pain model. Single sciatic nerve block, intravenous flurbiprofen or the combination of both were used for intervention. The sensory and motor functions after nerve block and incision were evaluated. The changes of IL-1β, IL-6, TNF-α, microglia and astrocytes in the spinal cord were examined by qPCR and immunofluorescence respectively.

Results

Sciatic nerve block with 0.5% ropivacaine in rats induced sensory block for 2h and motor block for 1.5h. In the rats with plantar incision, the single sciatic nerve block did not alleviate postoperative pain or inhibit the activation of spinal microglia and astrocytes, but the levels of IL-1β and IL-6 in spinal cord were decreased when the nerve block wore off. The combined effect of a single sciatic nerve block and intravenous flurbiprofen not only decreased the levels of IL-1β, IL-6, and TNF-α, but also relieved the pain and alleviated the activation of microglia and astrocytes.

Conclusion

The single sciatic nerve block cannot improve postoperative pain or inhibit the activation of spinal cord glial cells, but can reduce the expression of spinal inflammatory factors. Nerve block combined with flurbiprofen can inhibit spinal cord inflammation and improve postoperative pain. This study provides a reference for rational clinical application of nerve block.

Peripheral Nerve Blocks Outperform General Anesthesia for Pain Control in Arthroscopic Rotator Cuff Repair: A Systematic Review and Meta-analysis

PURPOSE

The purpose of this review is to compare the effectiveness of different peripheral nerve blocks and general anesthesia (GA) in controlling postoperative pain after arthroscopic rotator cuff repair (ARCR).

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant systematic review was conducted for the period of January 1, 2005, to February 16, 2021, by searching the following databases: PubMed, Cochrane, Embase, and Arthroscopyjournal.org. The primary outcomes of interest included 1-hour, 24-hour, and 48-hour pain scores on a numeric rating scale or visual analog scale (VAS). Inclusion criteria were English language studies reporting on adults (≥18 years) undergoing ARCR with peripheral nerve blockade. To synthesize subjective pain score data at each evaluation time point across studies, we performed random-effects network meta-regression analyses accounting for baseline pain score as a covariate.

RESULTS

A total of 14 randomized controlled trials with 851 patients were included in the meta-analysis. Data from six different nerve block interventions, single-shot interscalene brachial plexus nerve block (s-ISB; 37.8% [322/851]), single-shot suprascapular nerve block (s-SSNB; 9.9% [84/851]), continuous ISB (c-ISB; 17.5% [149/851]), continuous SSNB (c-SSNB; 6.9% [59/851]), s-ISB combined with SSNB (s-ISB+SSNB; 5.8% [49/851]), s-SSNB combined with axillary nerve block (s-SSNB+ANB; 4.8% [41/851]), as well as GA (17.3% [147/851]) were included. Our meta-analysis demonstrated that c-ISB block had a significant reduction in pain score relative to GA at 1-hour postoperation (mean difference [MD]: -1.8; 95% credible interval [CrI] = -3.4, -.08). There were no significant differences in VAS pain scores relative to GA at 24 and 48 hours postoperatively. However, s-ISB+SSNB had a significant reduction in 48-hour pain score compared to s-ISB (MD = -1.07; 95% CrI = -1.92, -.22).

CONCLUSIONS

It remains unclear which peripheral nerve block strategy is optimal for ARCR. However, peripheral nerve blocks are highly effective at attenuating postoperative ARCR pain and should be more widely considered as an alternative over general anesthesia alone.

LEVEL OF EVIDENCE

Level II Systematic review and meta-analysis of Level I and II studies.

Efficacy of Different Preemptive Analgesia on Postoperative Analgesia, Oxidative Stress, and Inflammatory Response after Gynecological Laparoscopic Surgery

Objective

To observe and compare the analgesic effects of oxycodone, pentazocine, and ketorolac tromethamine pre-emptive analgesia on gynecological laparoscopic patients after operation and the effects on oxidative stress and inflammatory reaction.

Methods

A total of 64 patients who underwent elective gynecological laparoscopic surgery in Yiwu Central Hospital from June 2019 to December 2020 were randomly divided into four groups (n = 16). Before anesthesia induction, oxycodone (group A), pentazocine (group B), ketorolac tromethamine (group C), and normal saline (group D) were, respectively, administered. Patients' mean arterial pressure (MAP) and heart rate (HR) changes, visual analogue scale (VAS), Bruggemann comfort scale (BCS), serum tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), blood glucose (CLU), serum cortisol level, postoperative adverse reactions, and additional analgesia were recorded at each time point.

Results

The MAP levels of T2 (immediate intubation), T3 (immediate catheter removal), and T4 (5 min after catheter removal) in the four groups were higher than those of T1 (quiescent state), and the HR levels T2, T3, and T4 were lower than those of T1 (P < 0.05). The MAP and HR levels of T2, T3, and T4 in patients of groups A, B, and C were lower than those of group D in the same period (P < 0.05). The VAS and BCS scores of groups A, B, and C at 1, 6, 12, and 24 h after operation were better than those of group D at the same time, and the scores of group A at 1 h and 6 h after operation were better than those of groups B and C at the same time (P < 0.05). The levels of serum TNF-α, IL-6, and CRP in the four groups of patients at 6, 12, and 24 h after operation were higher than those before operation, but those in groups A, B, and C were lower than those in group D, and those in group A were higher than those in groups B and C at 12 h and 24 h after operation (P < 0.05). The CLU and serum cortisol levels in the four groups were significantly higher at 6, 12, and 24 h after operation, but those in groups A, B, and C were lower than those in group D, and those in group A were lower than those in groups B and C at 6 and 12 h after operation (P < 0.05). There was no significant difference in the incidence of adverse reactions within 24 h between the four groups (P > 0.05). The incidence of additional analgesia in groups A, B, and C was lower than that in group D (P < 0.05).

Conclusion

Oxycodone, pentazocine, and ketorolac tromethamine are effective and safe in inhibiting postoperative pain and the generation of inflammatory factors and relieving inflammatory state in gynecological laparoscopic pre-emptive analgesia. Oxycodone has better postoperative analgesic effect because it can effectively alleviate stress reaction.