Applicability of the Clavien-Dindo grading system for assessing the postoperative complications of endoscopic surgery for nephrolithiasis: a critical review

OBJECTIVE: Adaptation of the Clavien-Dindo classification for assessing the severity of complications following the endoscopic treatment of nephrolithiasis and evaluation of its versatility and objectivity. MATERIAL AND METHODS: We retrospectively reviewed the medical records of 1027 patients who presented stones located in upper urinary tract (597 males, 58.1% and 430 females, 41.9%), mean age 38.9±15.6 (range, 4 to 84) years. The age ranged from 4 to 15 years in 46 (4.5%) of the patients. The mean size of the stones was 30.3±0.6 (range, 3 to 150) mm. Percutaneous nephrolithotomy (PNL) and ureteroscopy (URS) were performed by three experienced surgeons, PNL with the patients in the prone position. Fragmentation of stones was carried out using a pneumatic lithotripter. The outcomes were compared using Fisher's exact test and Student's t-test. The Clavien-Dindo grading system was used. RESULTS: We observed 195 (19.0%) patients who presented a total of 250 complications during the postoperative period. Additional interventions have been performed to eliminate 74 complications: 41 under general anesthesia and 33 without it. "Stone free status" was reached in 879 (85.6%) patients. Postoperative complications were assessed using Clavien grading system: Grade I for 64 complications (6.2%); Grade II for 111 (10.8%); Grade IIIa for 33 (3.2%); Grade IIIb for 39 (3.8%); Grade IVa for 3 (0.3%); Grade IVb for 0; and Grade V for 0. CONCLUSION: There is no ideal classification system for assessing the severity of surgical complications. The Clavien-Dindo classification can be adapted to assess the severity of postoperative complications following endoscopic procedures for nephrolithiasis if certain corrections are made.