Pre-Operative Parameters Predicting Hemoglobin Decline Related to Percutaneous Nephrolithotomy

Percutaneous nephrolithotomy (PNL) for upper urinary tract stones is a minimally invasive, effective treatment modality. Despite its high success rates, its potential complications pose a risk. In this study, we aimed to determine the risk factors associated with bleeding which is one of PNL's most important complications.

The data of patients who underwent PNL between January 2017 and December 2018 were retrospectively analyzed. The median reduction in post-operative hemoglobin levels compared to preoperative levels was found to be 1.6 g/dl, which was accepted as the threshold value. The patients with hemoglobin decrease above the threshold were assigned as Group 1, and below the threshold as Group 2. Pre-operative, perioperative data, and stone characteristics of the patients were recorded.

169 patients, 85 patients in Group 1 and 84 patients in Group 2 were included in the study. The mean age of Group 1 was significantly higher (47.4±7.9 and 32±9.4 years, respectively, p=0.001) Sixteen in Group 1 (18.8%) and six in Group 2 (7, 1%) had a diagnosis of hypertension (HT) and a significant difference was found (p=0.038). The average stone burden was 2733±1121.3 mm3 in Group 1, and 2326.5±975.6 mm³ in Group 2. It was observed that there was a significantly higher stone burden in Group 1 (p=0.001). There was a significant difference between the groups in terms of mean operation time (84.4±7 and 76.2±9.9 min, respectively, p<0.001). When the complication rates were analyzed, complications were observed in 25 (29.4%) patients in Group 1 and 12 (14.2%) patients in Group 2, and a significant difference was found between both groups (p=0.019). Age and HT were found to be significant independent risk factors associated with hemoglobin decline in multivariate analyzes (p<0.001 and p<0.027, respectively).

In this study; advanced age, presence of HT, and high stone burden were found to be predictive of reductions in hemoglobin levels. Furthermore, a correlation of decreased hemoglobin levels was detected with operative times and occurrence of complications.