Solitary kidney - a clinical challenge for endourologist

Retrograde intrarenal surgery for a staghorn renal calculus in a patient with solitary kidney and urinary tract deformity: a case report

Staghorn renal calculi are large, branched stones in the kidney that partially or completely fill the renal pelvis and renal calyces. Percutaneous nephrolithotomy (PCNL) is the gold standard treatment for staghorn calculi. However, we report a retrograde intrarenal surgery (RIRS) performed to treat a staghorn calculus in a patient with a solitary kidney and a deformed urinary tract. The 37-year-old male patient presented with right-sided lumbar pain. The computed tomography (CT) scan found a solitary kidney on the right side with an opaque 4.5 cm × 2.4 cm renal stone and grade I hydronephrosis. Additionally, a urinary tract deformity was observed, and it was secondary to the deformity of the pelvis caused by a previous pubis fracture, which significantly increased the risk and the difficulty of intrarenal surgery. A total number of 3 sessions of RIRS were conducted, and the patient was discharged 3 days after each session on average. The postoperative X-ray exam of the third session revealed that the renal stone was completely removed. The patient recovered well without any complications. This case demonstrates that RIRS is a safe and effective treatment of staghorn calculi with the presence of urinary tract deformation. This suggests RIRS may be of particular interest in minimizing the procedure-related damage of a solitary kidney.

Development and validation of a risk-prediction nomogram for patients with ureteral calculi associated with urosepsis: A retrospective analysis

Objectives

To develop and validate an individualized nomogram to predict probability of patients with ureteral calculi developing into urosepsis.

Methods

The clinical data of 747 patients with ureteral calculi who were admitted from June 2013 to December 2015 in Affiliated Nanhai Hospital of Southern Medical University were selected and included in the development group, while 317 ureteral calculi patients who were admitted from January 2016 to December 2016 were included in the validation group. The independent risk factors of ureteral calculi associated with urosepsis were screened using univariate and multivariate logistic regression analyses. The corresponding nomogram prediction model was drawn according to the regression coefficients. The area under the receiver operating characteristic curves and the GiViTI calibration belts were used to estimate the discrimination and calibration of the prediction model, respectively.

Results

Multivariate logistic regression analysis showed that the five risk factors of gender, mean computed tomography(CT) attenuation value of hydronephrosis, functional solitary kidney, urine white blood cell(WBC) count and urine nitrite were independent risk factors of ureteral calculi associated with urosepsis. The areas under the receiver operating characteristic curve of the development group and validation group were 0.913 and 0.874 respectively, suggesting that the new prediction model had good discrimination capacity. P-values of the GiViTI calibration test of the two groups were 0.247 and 0.176 respectively, and the 95% CIs of GiViTI calibration belt in both groups did not cross the diagonal bisector line. Therefore the predicted probability of the model was consistent with the actual probability which suggested that the calibration of the prediction model in both groups were perfect and prediction model had strong concordance performance.

Conclusion

The individualized prediction model for patients with ureteral calculi can facilitate improved screening and early identification of patients having higher risk of urosepsis.