The clinical and cost-effectiveness of paravertebral blockade versus thoracic epidural blockade in reducing chronic post-thoracotomy pain: TOPIC2 RCT synopsis.

Background: More than a third of patients undergoing thoracotomy suffer from debilitating chronic post-thoracotomy pain lasting months or years postoperatively. Aggressive management of acute pain during the perioperative period may mitigate this risk. Objective(s): To determine the clinical and cost-effectiveness of paravertebral blockade compared to thoracic epidural blockade, by testing the hypothesis that paravertebral blockade reduces the incidence of chronic post-thoracotomy pain. Design and methods: A parallel, open, multicentre, randomised controlled with integrated health-economic evaluation and an internal pilot that incorporated a qualitative recruitment intervention. Setting and participants: Adult patients undergoing thoracotomy in 15 United Kingdom centres. Interventions: Paravertebral blockade compared to thoracic epidural blockade. Main outcome measures: The primary outcome was the presence of chronic post-thoracotomy pain at 6 months post randomisation defined as 'worst chest pain over the last week' of at least moderate intensity, with a visual analogue scale score ≥ 40 mm. Secondary outcomes included visual analogue scale pain scores in the acute (days 1, 2, 3 and discharge) and chronic (3, 6 and 12 months) phases postoperatively; Brief Pain Inventory; Short Form McGill Pain Questionnaire 2; Hospital Anxiety and Depression Scale; patient satisfaction; analgesia use in the acute and chronic phases; complications (analgesic, surgical and pulmonary) and mortality. For the economic evaluation, the EuroQol-5 Dimensions, five-level version questionnaire was utilised. Results: Between 8 January 2019 and 29 September 2023, 770 patients underwent randomisation; 33 did not proceed to thoracotomy. At 6 months, 59 (22%) of 272 participants in the paravertebral blockade group and 47 (16%) of 292 in the thoracic epidural blockade group developed chronic pain [adjusted risk ratio = 1.32 (95% confidence interval 0.93 to 1.86); adjusted risk difference = 0.05 (95% confidence interval -0.01 to 0.11); Limitations: The main limitation is the reduced sample size from 1026 to 770, which reduced the associated power from 90% to 80%. The key reasons are related to practice change over time resulting in a downgrade in equipoise and the COVID pandemic. Also, we cannot rule out that lack of blinding may have had some impact on the acute phase outcomes. Conclusions: In our study, paravertebral blockade and thoracic epidural blockade appear to be equivalent in clinical and cost-effectiveness in preventing chronic post-thoracotomy at 6 months; this may be paving the way for both techniques likely to continue in National Health Service thoracic settings, based on clinician and patient's choices. Future work: Using full TOPIC-2 data sets, defined according to the European Society of Thoracic Surgeons data set, to explore the trajectory of the development from acute to chronic post-surgery pain. Funding: This synopsis presents independent research funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme as award number 16/111/111.