Here is the design of a clinical trial:

Official Title: Laparoscopic Ischemic Conditioning Prior to Esophagectomy in Patients With Esophageal Cancer and Arterial Calcifications

Included conditions:
- Esophageal Cancer

Study Armgroups:
- {'label': 'Laparoscopic ischemic conditioning followed by esophagectomy', 'type': 'EXPERIMENTAL', 'description': 'All included patients will receive a laparoscopic ischemic conditioning followed by an esophagectomy after an interval of 12-18 days.', 'interventionNames': ['Procedure: Laparoscopic ischemic conditioning followed by esophagectomy']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'Laparoscopic ischemic conditioning followed by esophagectomy', 'description': 'All included patients will receive a laparoscopic ischemic conditioning followed by an esophagectomy after an interval of 12-18 days.', 'armGroupLabels': ['Laparoscopic ischemic conditioning followed by esophagectomy']}

Primary Outcomes:
- {'measure': 'Number of participants with a grade 2 or higher complication after laparoscopic ischemic conditioning', 'description': 'Complications grade 2 and higher (Clavien-Dindo classification)', 'timeFrame': 'Occuring after operation 1(laparosocpic ISCON), but before operation 2 (esophagectomy). This time-frame is usually 13-15 days.'}

Please estimate the sample size based on the assumption: 
No formal sample size calculations are performed.
Sample size
        This is a prospective single arm safety and feasibility trial, classified as a âstage 2a Developmentâ study according to the IDEAL recommendations for surgical innovation [19]. Based upon these recommendations, a total of 20 subjects will be included and no formal sample size calculations are performed (10 patients per centre).