https://epoc.cochrane.org/sites/epoc.cochrane.org/files/public/uploads/Resources-for-authors2017/how_to_prepare_a_risk_of_bias_table_for_reviews_that_include_more_than_one_study_design.pdf

Thank you a lot for your response. I will include this risk of bias checklist in my article.

Dear Sara

Thanks indèed for your quetion. Nowadays we have a procedure specifically built to avoid bias called power analysis. Suppose you u will take N1 number with phantom pain, ok how much this number will decrease after your treatment N2? So from the difference between N1 minus N2 and from the overall incidence of phantom psin the software will calculate for you the required initial sample size to avoid bias with 80% to 95% according to your required accuracy.

Software like MEDCALC can easily calculate it for you. In case you need help tell me the global incidence of phantom pain i will calculate for you minimum sample size required in your work

Good luck

Wisam