Introducing trifecta for percutaneous nephrolithotomies: a proposal for standard reporting outcomes after treatment...

In literature, the reports of outcomes after percutaneous nephrolithotomies are rather heterogeneous. This may influence studies comparison, it may also render difficult to evaluate surgical adequacy, perioperative morbidity, and patient's Quality of Life between studies. For this reason, we propose to introduce PNL-Trifecta as composite measure to standardize data reporting outcomes after percutaneous nephrolithotomies.

We performed a prospective multicentric study on consecutive patients undergone PNL to treat renal stones between 2018 and 2020. Successful PNL-trifecta was considered achieved when procedures obtained the three following results: no residual fragments >2 mm at unenhanced CT scan at 3 months postop, no complications (defined as Clavien-Dindo Score 0) and operation carried out without placing a nephrostomy tube (tubeless or totally tubeless). We compared results of standard versus mini-PNL and between stones of different complexity (evaluated with Guy's Stone Score and S.T.O.N.E. Nephrolithometry Score). Univariate analysis was utilized to identify other factors influencing achievement of PNL-Trifecta.

Two hundred forty-five patients fulfilled inclusion/exclusion criteria and have been enrolled in the study (median age: 56, IQR 48-57). The overall PNL-Trifecta achievement rate was 22.85% (28.66% in the mini-PNL group and 13.68% in the standard-PNL group, P=0.010). The stone free rate, CD 0 rate and tubeless/totally tubeless rate in the mini-PNL group were 60.66%, 89.33% and 51.33% respectively. In the standard-PNL group they were 44.21%, 40.00% and 15.78% respectively. At the univariate analysis, differences between Guy's Stone Score groups in achieving PNL-Trifecta were significant (P=0.001). Also, the level of upper puncture (P=0.010) and utilization of device with active suction (P=0.002) showed statistically significant differences. Furthermore, the length of stay in the patient's group achieving Trifecta was 2.28 versus a mean length of stay of 4.64 days in the group of patients not achieving Trifecta (P=0.046).

We present Trifecta for PNLs as a potential tool to evaluate quality of percutaneous nephrolithotomies and to provide an instrument for an adequate standard data reporting. It can represent a valid way to assess and monitor surgeon's learning curves. It will require further external validation and studies to evaluate its correlation with mid- and long-term results and patient's health related Quality of Life outcomes.