Outcome and safety of upper pole versus non-upper pole single puncture PCNL for staghorn stones: A systematic review and meta-analysis [version 1; peer review: 1 approved with reservations]

Background: Staghorn stones are mostly treated by percutaneous nephrolithotomy (PCNL), either with an upper-pole (UP) or non-upper (lower- or middle-) pole (NP) approach. NP access has a lower risk of bleeding and thoracic complications but may not be sufficient for complete stone clearance. UP access is advocated as the preferred approach, because of direct access to the collecting system. However, it is associated with a higher complications rate, including pneumothorax and hydrothorax, and a higher risk of bleeding. This meta-analysis aimed to describe the outcomes and safety of PCNL for staghorn stones using UP and NP approaches. Methods: A systematic literature review was conducted using several databases such as: PubMed; EBSCO; Science Direct; Cochrane and Google Scholar. Data from all selected articles were extracted by two independent reviewers. Relevant parameters explored using Review Manager V5.3. Results: Five comparative studies of staghorn stones involving 384 renal units were analyzed; 176 cases used the UP approach and 208 the NP approach. There was no significant difference in stone-free rate between these approaches, with 74.4% undergoing the UP approach and 71.1% the NP approach considered stone-free (OR: 1.55; 95% CI: 0.92-2.63; P=0.10). The rate of thoracic complications (hydrothorax and pneumothorax) did not differ significantly (OR: 3.14; 95% CI: 0.63-15.62; P=0.16). However, we noted that 5 of 176 patients that underwent the UP approach experienced thoracic complications. The incidence of post-procedural fever and sepsis is similar (OR: 1.18; 95% CI: 0.52-2.64; P=0.69). Neither post-procedural urine leakage (OR: 2.03; 95% CI: 0.70-5.85; P=0.19) nor requirement of blood transfusions (OR: 0.49; 95% CI: 0.14-1.76; P=0.27) differed significantly. Conclusion: PCNL with UP access for staghorn stone has a similar stone-free rate to the NP approach. Thoracic complication rate which was believed to be higher in the UP group is also deemed similar with NP access.