The review question was clear and was supported by potentially replicable inclusion criteria. The search strategy included relevant data sources and attempts were made to minimise language bias. The search dates were not stated, which made it difficult to interpret whether searching was up-to-date; there was no apparent search for unpublished material. The potential for publication bias was unclear as the results of the reported assessment were not presented. The review process was conducted with efforts to minimise error and bias
Appropriate quality assessment criteria were applied to the included studies. Study details were sparse for patients and intervention characteristics, which made it difficult to interpret the generalisability of findings. It appeared there might have been some confusion in the reported design of included studies. The authors stated that these were case-control but, based on the available information, it appeared more likely that they were cohort studies as they had groups of patients with percutaneous nephrolithotomy in the supine and prone positions, rather than selecting groups of patients based on outcome. The authors acknowledged that the evidence base was limited.
Although there were potential gaps in the search, the review was largely well conducted and the authors' conclusions are likely to be reliable.