Background: Regional anaesthesia is widely used in clinical practice, offering significant benefits but carrying risks such as nerve damage and other complications. Understanding medicolegal trends associated with regional anaesthesia is essential for improving patient safety and refining practices.

Objectives: To analyse closed claims related to regional anaesthesia in Switzerland over the past 30 years, identify trends in complications and assess their medicolegal implications.

Design: Retrospective analysis of the Swiss Anaesthesiology Closed Claims Analysis database, focusing on cases involving regional anaesthesia from 1992 to 2022.

Setting: The study was conducted using data from Swiss medical malpractice insurers and the Swiss Society of Anaesthesiology and Perioperative Medicine together with their Foundation for Patient Safety in Anaesthesia.

Patients: A total of 244 closed claims of patients were reviewed, of which 140 cases involved regional anaesthesia.

Interventions: None.

Main outcome measures: Key measures included patient demographics, type of anaesthesia, complications, adherence to best practices and legal outcomes such as liability acceptance and compensation amounts.

Results: The number of claims involving regional anaesthesia decreased significantly over three decades, from 69 (49%) in the first decade to 30 (21%) in the last. Nerve damage was the most common complication (76%), with a notable reduction in permanent injuries from 57 to 28%. Advances in ultrasound-guided techniques and improved documentation may have contributed to these trends. Male patients tended to have higher rates of nerve injuries, while female patients reported more nonspecific pain syndromes and posttraumatic stress disorders because of the health impairment associated with the liability case. Liability was accepted in 43% of cases, with compensation often exceeding CHF 100 000. The highest compensations seemed to have been paid to male patients.

Conclusions: The decline in claims may reflect advancements in anaesthetic techniques and safety practices. This study underscores the importance of communication and training best practices in regional anaesthesia, including sufficient patient information and documentation to enhance patient safety and reduce medicolegal risks. Pain during performance, multiple attempts and re-injections should be avoided whenever possible.