Here is the design of a clinical trial:

Official Title: A Randomized Controlled Trial to Study the Effectiveness and Cost-effectiveness of Contralateral Surgical Exploration During Unilateral Inguinal Hernia Repair in Children.

Included conditions:
- Inguinal Hernia

Study Armgroups:
- {'label': 'Intervention group', 'type': 'OTHER', 'description': 'Unilateral inguinal hernia repair with contralateral exploration.', 'interventionNames': ['Procedure: Contralateral exploration']}
- {'label': 'Control group', 'type': 'NO_INTERVENTION', 'description': 'Unilateral inguinal hernia repair.'}

Interventions:
- {'type': 'PROCEDURE', 'name': 'Contralateral exploration', 'description': "Surgery eventually performed when a patent processus vaginalis or hernia exists on the other side than the side on which the child has to be operated on, will be exactly the same as the inguinal hernia repair on the 'symptomatic' side. Exploration of the contralateral side will increase anaesthesia time by 10-15 minutes.", 'armGroupLabels': ['Intervention group']}

Primary Outcomes:
- {'measure': 'Proportion of infants that undergo a second operation', 'description': 'The number of infants that undergo a second operation related to unilateral inguinal hernia within one year after primary inguinal hernia repair', 'timeFrame': 'One year after primary hernia repair'}

Please estimate the sample size based on the assumption: 
The sample size calculation is based on a power of 0.80 and a two-sided alpha of 0.05. A 10% loss to follow-up is also considered.
Sample size {14}
      Data from the latest systematic review shows that the incidence of infants younger than 6 months of age who develop MCIH is 12.4% [4]. Retrospective data from the Emma Childrenâs Hospital AMC, where in 2000/2001 contralateral exploration was routinely performed, shows similar results: 8/92 patients did not undergo contralateral exploration and subsequently one patient (12.5%) developed MCIH. Eighty-four patients underwent unilateral hernia repair with contralateral exploration of which one patient (1.2%) developed MCIH.
      The expected percentage of children requiring one or more reoperations because of MCIH in the first year following hernia repair is approximately 10%. We consider a reduction of children requiring reoperation from 10 to 2.5% as clinically relevant. A total sample size of 378 patients is needed to detect such a reduction with a power of 0.80 at a two-sided alpha of 0.05 (nQuery Advisor 7.0) [29]. Taking into account 10% loss to follow-up, we need to include 416 children.