Here is the design of a clinical trial:

Official Title: Vagus Nerve Stimulation for Pediatric Intractable Epilepsy (VNS-PIE)

Included conditions:
- Refractory Epilepsy

Study Armgroups:
- {'label': 'Experimental', 'type': 'EXPERIMENTAL', 'description': "Subjects'Vagus Nerve stimulator is on always", 'interventionNames': ['Device: PINS Vagus Nerve Stimualtor']}
- {'label': 'Control', 'type': 'SHAM_COMPARATOR', 'description': "Subjects'Vagus Nerve stimulator is off from enrollment to 3 month", 'interventionNames': ['Device: PINS Vagus Nerve Stimualtor']}

Interventions:
- {'type': 'DEVICE', 'name': 'PINS Vagus Nerve Stimualtor', 'description': 'PINS Vagus Nerve Stimualtor', 'armGroupLabels': ['Control', 'Experimental']}

Primary Outcomes:
- {'measure': 'Changes in seizure frequency', 'timeFrame': '12 weeks of stimulation'}

Please estimate the sample size based on the assumption: 
The standard deviation of the two groups is set at 35%. The significance level (α) is 0.025 for a unilateral test (0.05 for a bilateral test if needed), and the power (1-β) is 0.8, with a second-class error level (β) of 0.2. The maximum possible loss rate is 10%.
Sample size
        We adopted a pilot study design to evaluate efficacy and to primarily quantify the frequency of seizure reduction between the EG and the CG at 12âweeksâ follow-up after VNS treatment. It has been estimated that the variation of seizure frequency in the EG (VNSâ+âAEDs) will be conservatively higher (25%) than the CG (AEDs only). The standard deviation of the two groups is set at 35%. Therefore, the sample size calculation formula is:1\documentclass[12pt]{minimal}
				\usepackage{amsmath}
				\usepackage{wasysym} 
				\usepackage{amsfonts} 
				\usepackage{amssymb} 
				\usepackage{amsbsy}
				\usepackage{mathrsfs}
				\usepackage{upgreek}
				\setlength{\oddsidemargin}{-69pt}
				\begin{document}$$ n=\frac{2{\left({\mu}_{\alpha /2}+{\mu}_{1-\beta}\right)}^2{\sigma}^2}{{\left({x}_T-{x}_C\right)}^2}, $$\end{document}n=2Î¼Î±/2+Î¼1âÎ²2Ï2xTâxC2,where xT is the expected curative effect of the EG, xC is the expected curative effect of the CG, Ï is the standard deviation of the two groups (35%), Î¼ is the quantile of the standard normal distribution, Î± is the first-class error level for statistical test (0.025, here for unilateral test; 0.05 for bilateral test if need), and Î² is the second-class error level for statistical test (0.2, here). The calculated sample size per group through this calculation is 38. Considering that the maximum possible loss rate is 10%, the final sample size is 42 pairs (Nâ=â84) [43â45] .