Here is the design of a clinical trial:

Official Title: A Randomised Controlled Trial to Investigate the Effectiveness of ThOracic Epidural and Paravertebral Blockade In Reducing Chronic Post- Thoracotomy Pain: 2

Included conditions:
- Anesthesia
- Thoracic Diseases

Study Armgroups:
- {'label': 'Paravertebral Blockade', 'type': 'EXPERIMENTAL', 'description': "Anaesthesia to single side of the patient's chest", 'interventionNames': ['Procedure: Paravertebral blockade']}
- {'label': 'Thoracic epidural block', 'type': 'ACTIVE_COMPARATOR', 'description': "Anaesthesia to both sides of the patient's chest", 'interventionNames': ['Procedure: Thoracic epidural block']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'Paravertebral blockade', 'description': 'Type of anaesthesia', 'armGroupLabels': ['Paravertebral Blockade']}
- {'type': 'PROCEDURE', 'name': 'Thoracic epidural block', 'description': 'Type of anaesthesia', 'armGroupLabels': ['Thoracic epidural block']}

Primary Outcomes:
- {'measure': 'Incidence of chronic pain: incidence = score > 40 on visual analogue score', 'description': 'Patient reported pain lasting at least 3 months as measured by visual analogue score', 'timeFrame': '6 months post trial thoracotomy'}

Please estimate the sample size based on the assumption: 
90% power, two-sided significance level of 0.05, 10% rate of death by 6-month follow-up, 15% loss to follow-up at 6 months
Sample size {14}
        Assuming a 30% incidence of CPTP in the TEB group (similar to that seen in our previous TOPIC-pilot trial results [12] and systematic review [13], 392 patients in each group will give 90% power (two-sided, pâ=â0.05) to detect a 10% absolute reduction (i.e. down to 20%, a 33% relative reduction) in the PVB group. Assuming a 10% rate of death by 6-month follow-up (similar to that seen in the TOPIC pilot) and a further 15% loss to follow-up at 6Â months, we will recruit a total of 1026 participants.