Photo Credit: Mohammed Haneefa Nizamudeen

Higher BMI, urinary white blood cell abnormalities, prolonged stent use, and low water intake raised the risk for double-J stent encrustation after urinary surgery.

Higher BMI, preoperative urinary white blood cell abnormalities, prolonged stent placement, and insufficient water intake significantly increased the risk for double-J stent encrustation following upper urinary tract surgery, according to a study published in Urolithiasis.

Weihui Jia and colleagues wrote that their findings emphasize the importance of personalized weight management, infection control, timely stent removal, and consistent hydration in preventing complications for patients with urinary stones.

Double-J ureteral stents are commonly used to manage ureteral obstructions caused by conditions like urinary stones, tumors, and stenosis, but stent encrustation can complicate stent removal and lead to severe outcomes, such as ureteral rupture. Current treatments focus on symptom management, as no comprehensive prevention strategy exists.

The study authors collected clinical data from 802 patients to develop and validate a predictive model for stent encrustation, which will identify high-risk patients and guide preventive clinical interventions.

The study included 802 patients with indwelling double-J stents following upper urinary tract stone surgery between 2019 and 2022. Patients were divided randomly into a modeling group (n=561) and a verification group (n=241). Patients lacking complete records, those with unremoved stents, and those with severe urinary conditions were excluded from the analysis.

A clinical questionnaire was developed with input from 10 urology experts and included 18 risk factors related to patient demographics, stent status, surgical details, and follow-up care, such as water intake. Researchers analyzed stone composition using infrared spectroscopy.

The study team performed statistical analyses, including logistic regression and ROC curves, using SPSS and R software to identify risk factors for stent encrustation and validate the predictive model. Internal validation was conducted using the bootstrap method, and calibration was assessed with the Hosmer–Lemeshow test.

“In this study, 104 of the 561 patients in the modeling group developed double-J stent encrustation, with an incidence rate of 18.5%,” said the authors. “In 104 patients, the simple stones were mainly composed of anhydrous uric acid 53.85% (56/104) and calcium oxalate monohydrate 10.58 (11/104); mixed stones are mainly calcium oxalate + calcium phosphate 6.74% (7/104).”

The authors identified four independent risk factors for double-J stent encrustation:

• BMI greater than 23.9 (P=0.047)
• Preoperative urine white blood cell count (P<0.001)
• Stent insertion time (P<0.001), and
• Postoperative daily water intake (P=0.017).

The researchers advocated for targeted interventions, including weight management, early detection and treatment of infections, timely stent removal, and patient education on adequate water consumption. These measures can help reduce the risk of stent encrustation and improve patient outcomes.

“Medical staff should emphasize that the amount of drinking water should be more than 2000 mL daily and recommend that patients carry drinking water bottles with scales or capacity marks every day to improve patient compliance,” said the authors. “At the same time, medical staff should strengthen follow-up visits, adopt live webcasts…and other means to make patients aware of the importance of drinking more water for the prevention of double-J stent encrustation.”

While the study demonstrated strong predictive ability, the authors acknowledged its limitations, including its retrospective design, single-center setting, and lack of data on other potential factors like diet and lifestyle. They noted that future research should aim to validate the model with larger, multi-center studies to enhance its clinical utility.

However, in the meantime, authors “recommend that clinical staff use this risk prediction model to implement targeted interventions to reduce the probability of double-J stent encrustation.”