Purpose To identify the predictors of nadir serum creatinine (SCr) after drainage of bilaterally obstructed kidneys (BOKs) by different modes: double-J stent (JJ) versus percutaneous nephrostomy (PCN) and unilateral versus bilateral drainage. Methods A prospective non-randomized study was performed on patients with BOKs and raised SCr during December 2019–November 2021. Relevant variables were studied for improvement and non-improvement and for benign and malignant underlying obstructions (BUO and MUO). Results This study included 107 patients with BOKs including 68 (63.6%) males and 39 (36.4%) females. After drainage, 86 (80.4%) patients get improved, while 21 (19.6%) patients failed to reach a nadir SCr. Drainage by PCN was significantly higher in MUO, while JJ was significantly higher in BUO (p < 0.001). Also, bilateral drainage was a significant predictor of improvement in MUO (p = 0.03). In contrast, mode of drainage had no significant effect on improvement in BUO (p = 0.84), but bilateral drainage was a significant factor of rapid time to nadir (p = 0.02). Univariate analyses revealed no significant effects on the improvement in SCr from the studied variables, except the male gender (p = 0.01), old age (p < 0.001), MUO (p = 0.01), unilateral drainage (p < 0.001), and use of PCN for drainage (p < 0.001). By multivariate analysis, unilateral drainage (p = 0.01) and MUO (p < 0.001) were independent predictors of non-improvement in patients with BOKs. Conclusions Male gender, old age, MUO, unilateral drainage, and drainage by PCN were significant predictors of non-improvement in SCr after drainage of BOKs. However, unilateral drainage and MUO were the only independent predictors of non-improvement.

There is a well-known relationship between malignancy and impairment of kidney functions, either in the form of acute kidney injury or chronic kidney disease. In the former, however, bilateral malignant ureteral obstruction is a surgically correctable factor of this complex pathology. It warrants urgent drainage of the kidneys in emergency settings. However, there are multiple controversies and debates about the optimal mode of drainage of the bilaterally obstructed kidneys in these patients. This review addressed most of the concerns and provided a comprehensive presentation of this topic from the recent literature. Also, we provided different perspectives on the management of the bilateral obstructed kidneys due to malignancy. Despite the frequent trials for improving the success rates and functions of ureteral stents, placement of a percutaneous nephrostomy tube remains the most recommended tool of drainage due to bilateral ureteral obstruction, especially in patients with advanced malignancy. However, the disturbance of the quality of life of those patients remains a major unresolved concern. Beside the unfavorable prognostic potential of the underlying malignancy and the various risk stratification models that have been proposed, the response of the kidney to initial drainage can be anticipated and evaluated by multiple renal prognostic factors, including increased urine output, serum creatinine trajectory, and time-to-nadir serum creatinine after drainage.

Background There are persistent controversies about the outcomes and benefits of drainage of malignant ureteral obstruction by percutaneous nephrostomy (PCN). This study aimed to assess the predictors of the time-to-nadir (TTN) of serum creatinine (SCr) levels after drainage of bilaterally obstructed kidneys (BOKs) due to bladder cancer (BC) by PCN. Materials and methods This prospective nonrandomized study included patients with BOKs due to BC treated by PCN between April 2019 and March 2022. The primary outcome measure was TTN. Results Of the 55 patients with a median age (range) of 66 years (47–86 years), 32 (58.2%) had a normal nadir SCr and 23 (41.8%) had a high nadir SCr within 21 days after drainage of BOKs due to BC. High nadir SCr was associated with a higher mean age (p = 0.011) and lower body mass index (BMI, p = 0.043). However, patients with normal nadir SCr had a significantly shorter TTN (p = 0.023) and an increased mean SCr trajectory (p < 0.001) during TTN. In multivariate analysis, low urine output at presentation (p = 0.021) and high BMI (p = 0.006) were associated with longer TTN. However, the mean parenchymal thickness (p = 0.428) and laterality of drainage (p = 0.466) were not associated with the mean TTN and SCr normalization rates. According to the modified Clavien-Dindo classification, 8 cases of hematuria were managed conservatively (grade 2), and 2 cases of PCN slippage were repositioned using local anesthesia (grade 3). Conclusions Despite the safety of PCN for drainage of BOKs due to BC, more than 41% of the patients failed to have a normal nadir SCr. Predrainage low urine output and high BMI were associated with longer TTN. Laterality of drainage had no significant effects on the TTN and SCr trajectory.

Background Serum creatinine trajectory (SCr-Tr) is a neglected prognostic tool for chronic and acute kidney injury. We aimed to assess the predictors of SCr-Tr during the time-to-nadir and serum creatinine (SCr) normalization rate after drainage, using percutaneous nephrostomy in patients with bilateral malignant ureteral obstruction. Methods A prospective non-randomized study was performed on SCr-Tr in patients with bilateral malignant ureteral obstruction from August 2019 to March 2022. The primary outcome was SCr-Tr during the time-to-nadir. Results This study included 102 patients with a mean age ± SD of 59.6 ± 14.7 years. SCr-Tr was non-linear with a mean ± SD (range) of 0.5 ± 0.4 (0.03–2.3) mg/dl/day. Multivariate analyses revealed that female gender (p = 0.016), body mass index (BMI; p = 0.005), and SCr at presentation (p < 0.001) were predictors of rapid SCr-Tr during the time-to-nadir. However, age (p = 0.008) and low urine output at presentation (p = 0.015) were associated with a lower SCr-Tr. In contrast, laterality of drainage (p = 0.544) and mean parenchymal thickness (p = 0.066) were not associated with mean SCr-Tr. Also, only the mean parenchymal thickness (p = 0.002) was a predictor of rapid SCr-Tr at ≥ 0.5 mg/dl/day. However, low BMI (p = 0.023) was associated with a high SCr normalization rate, while unilateral drainage (p = 0.045) was associated with a lower rate. Conclusions Female gender, low BMI, and SCr at presentation were predictors of rapid SCr-Tr during the time-to-nadir. Bilateral drainage was an independent predictor of SCr normalization rate, but not of rapid SCr-Tr. The mean parenchymal thickness was the only independent predictor for rapid SCr-Tr at ≥ 0.5 mg/dl/day.