Prone versus lateral retroperitoneoscopic partial nephrectomy for posterior tumors in adults: technique and clinical outcomes.

Background: Very limited information is available about the prone retroperitoneoscopic partial nephrectomy (RPN) in adults. This study aimed to evaluate the feasibility and clinical outcomes of prone RPN for posterior tumors in comparison with traditional lateral RPN in adults.

Methods: The recordings of 101 patients underwent RPN from January 2018 to March 2023 were retrospectively reviewed. Fifty-nine patients underwent surgeries with lateral RPN, and 42 underwent surgeries with prone RPN. Operative time, warm ischemia time, blood loss, renal function, operative complications, and arterial blood gas analysis were recorded and compared between the two groups. Additionally, a dorsal deviation score (DDS) was developed to quantitate the degree to which the tumor was dorsal, which helped to select a suitable operative approach clinically.

Results: Patients in prone RPN group had shorter operative time (P<0.001), warm ischemia time (P=0.003), and less blood loss (P=0.03) in comparison with lateral RPN. In arterial blood gas analysis, no significant differences in arterial partial pressure of carbon dioxide (PaCO₂), arterial partial pressure of oxygen (PaO₂), and pH were observed between two groups before the operation and 30 min after positioning. For slightly posterior tumors (DDS =1), no significant difference in above parameters was observed. However, shorter operative time (P=0.03, P<0.001, respectively), warm ischemia time (P=0.02, P=0.03, respectively), and less blood loss (P=0.08, P=0.043, respectively) were noticed in prone RPN for moderate or severe posterior (DDS =2 or 3) tumors, especially posterior hilar tumors. Difference in renal function between two groups was insignificant. As for complications, a higher incidence of intraoperative complications appeared in lateral RPN group (11.9%) compared with prone RPN (2.4%), whereas there was no significant difference in postoperative complications.

Conclusions: Prone RPN is a feasible operative approach in clinical practice, and is superior to lateral RPN for moderate to severe posterior tumors, especially posterior hilar tumors.