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); p = 0.12]. During the acute phase, both worst and average pain was higher on day 1 with paravertebral blockade [adjusted mean difference 7.7 mm (95% confidence interval 2.8 to 12.5) and 7.0 mm (95% confidence interval 2.7 to 11.2), respectively] but not different on days 2 and 3. Hypotension was less common in the paravertebral blockade group [adjusted risk ratio = 0.66 (95% confidence interval 0.46 to 0.94)], and overall complications were comparable between groups. The health-economic analysis demonstrated that thoracic epidural blockade produced an additional 0.04 quality-adjusted life-years when compared to paravertebral blockade, and was associated with slightly lower costs, but these differences were not statistically significant. 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.