Data extraction
Two study authors (PK & TP) independently extracted data from the
included studies on a pre-determined format including following
variables such as First author, year, type of study, country, type of
treatment, duration of treatment, baseline comparability according to
age, sex, stone size, stone expulsion rate and time to stone expulsion.
Discrepancy of data was resolved after arbitration with other study
authors (GS & ST).