Development and Validation of Metrics for Assessment of Ultrasound-Guided Fascial Block Skills

Academic Background

Postoperative pain following lumbar spine surgery is a significant clinical issue that can persist for weeks, impacting patient recovery and quality of life. Traditional analgesic methods, including multimodal analgesia (such as strong opioids, acetaminophen, and nonsteroidal anti-inflammatory drugs), are widely available and relatively effective but have certain limitations. In recent years, the Erector Spinae Plane Block (ESPB), a fascial plane block technique, has gradually been applied for postoperative analgesia in lumbar spine surgery. ESPB involves injecting local anesthetics at the tip of the transverse process, effectively alleviating postoperative pain, reducing opioid consumption, and shortening hospital stays. However, the successful implementation of ESPB relies on the precise skills of anesthesiologists under ultrasound guidance, a skill not universally possessed by all anesthesiologists. Therefore, how to effectively assess and train anesthesiologists in ultrasound-guided fascial block skills has become an urgent issue.

The primary objective of this study was to develop and validate a checklist for assessing ultrasound-guided fascial block skills, using soft-embalmed Thiel cadaver models. This study provides a skill assessment tool for future randomized controlled trials (RCTs) to ensure that anesthesiologists can correctly perform lumbar ESPB, thereby reducing postoperative pain, opioid consumption, and promoting patient recovery.

Source of the Paper

This paper was co-authored by Graeme McLeod and other researchers from multiple UK medical institutions, including NHS Tayside, University of Dundee, University of Sheffield, and University of Nottingham. The paper was published online ahead of print on August 8, 2024, in the British Journal of Anaesthesia, titled Development and validation of metrics for assessment of ultrasound-guided fascial block skills.

Research Process and Results

1. Development of the Checklist

The study first developed an 11-step checklist using the Delphi method to assess ultrasound-guided fascial block skills. Twenty-four UK regional anesthesia consultants participated in the Delphi questionnaire, ultimately identifying 11 key steps covering all aspects from preoperative preparation to injection procedures. These steps included selecting the appropriate transducer, optimizing ultrasound images, identifying the fascial plane, needle positioning before insertion, and needle tip identification.

2. Validation of the Checklist

To validate the checklist, the study recruited 12 expert and 12 novice anesthesiologists to perform lumbar and thoracic erector spinae plane injections, as well as other fascial blocks (such as fascia iliaca and pectoral-serratus injections), on soft-embalmed Thiel cadaver models. All procedures were recorded, and six trained raters blinded to the operator and site of the block evaluated 120 videos each.

3. Main Results

• Internal Consistency: The internal consistency (Cronbach’s alpha) of the checklist was 0.72 (95% confidence interval: 0.63-0.79), indicating good internal consistency.
• Performance Differences Between Experts and Novices: The median checklist scores were significantly higher for experts than novices (8.0 vs 7.0, p<0.001), demonstrating that the checklist effectively distinguished between expert and novice skill levels.
• Global Rating Scale (GRS): GRS scores also showed significant differences between experts and novices (median 28.0 vs 21.0, p<0.001), with a high correlation between GRS and checklist scores (r=0.63, p<0.001).
• Item Difficulty Analysis: Rasch analysis revealed that the most challenging steps were “identifying the needle tip before advancing the needle” and “always visualizing the needle tip.”

4. Conclusions

The study developed and validated an 11-step checklist for assessing ultrasound-guided fascial block skills using soft-embalmed Thiel cadaver models. The checklist demonstrated good construct validity and reliability, effectively distinguishing between expert and novice skill levels. The results suggest that this checklist can be used to train anesthesiologists, ensuring they can correctly perform lumbar ESPB in future RCTs, thereby reducing postoperative pain, opioid consumption, and promoting patient recovery.

Highlights of the Study

1. First Development and Validation of a Checklist for Fascial Block Skill Assessment, filling a gap in this field.
2. Validation Using Soft-Embalmed Thiel Cadaver Models, ensuring the reliability and clinical relevance of the assessment.
3. High Correlation Between the Checklist and Global Rating Scale, indicating comprehensive assessment of anesthesiologists’ skills.
4. Findings Support the Importance of Fascial Block Skill Training, providing a reliable skill assessment tool for future RCTs.

Significance and Value of the Study

The scientific value of this study lies in the first development and validation of a checklist for fascial block skill assessment, providing a quantitative tool for anesthesiologists’ skill training. Its practical value lies in effectively assessing anesthesiologists’ skill levels, ensuring they can correctly perform fascial blocks in clinical practice, thereby improving postoperative analgesia, reducing opioid use, and promoting patient recovery. Additionally, this checklist can be applied to assess other fascial block skills, offering broad clinical application prospects.

Other Valuable Information

The study also found that although expert skill levels were significantly higher than those of novices, the distribution of expert scores was wide, indicating that even experienced anesthesiologists face certain difficulties in fascial block procedures. This finding suggests that fascial block skill training needs to be more systematic and refined to ensure all anesthesiologists can achieve a high level of proficiency.

This study provides an important tool and methodology for the assessment and training of fascial block skills, with significant clinical and academic implications.