Abstract
In this study, both the groups (ultrasonography [US] and fluoroscopy) were matched on the basis of sex, history of PCNL, anticoagulant use, presence of staghorn stone, and the specialist who performed the renal access during the PCNL, but the stone burden and grading of dilation of the pelvic caliceal system (PCS) were not used for matching the groups. The mean stone burden was significantly higher in the fluoroscopy group compared with US group, which may lead to more operative time and intraoperative complications and bias the results. Similarly, the grading of the PCS dilation is an important factor. Greater dilation of the PCS usually makes access easy by any method, while in a nondilated system, access will be more difficult. We are of the opinion that these are important parameters and should be comparable and can be mentioned as a limitation of the study.
In Table 4, the mean operative time is mentioned as statically nonsignificant between the two groups (P=0.08) but has been written as significant in the description (page 26, P=0.039), which is conflicting and requires correction.
Table 4 also shows that the number of colon perforations in each group is 0, but in the discussion, the authors mention that colon perforations were observed in the fluoroscopy group; this needs clarification.
Many parameters used in this study, such as bleeding, blood transfusion, preoperative CT scan, postoperative stent placement, and operative time, are usually influenced/governed by local clinical practices, hospital policy, and surgeons' skill and are difficult to interpret.
Table 1 show that US-guided access was used much less than fluoroscopy-guided access. In many countries, US-guided access was used in only one or two patients. This number is too small and if in these centers it is used rarely, then the expertise of gaining access using US will be compromised. We think that such data should not have been included in the analysis.