Percutaneous Nephrolithotomy for Removal of Encrusted Ureteral Stents: A Multicenter Study
Bibliographic record
Abstract
PURPOSE: Encrusted ureteral stents are a challenging endourologic problem. We performed a multi-institutional review of percutaneous nephrolithotomy (PCNL) as primary treatment for encrusted stents. MATERIALS AND METHODS: We identified 36 patients who underwent PCNL for treatment of an encrusted stent. A retrospective review was performed to compile details of procedures and outcomes for these patients. RESULTS: In 36 patients, 38 renal units underwent PCNL for encrusted ureteral stents. The mean patient age was 47.1 years (±16.7), and the female:male ratio was 15:21. Mean stent indwelling time before removal was 28.2 months (±27.8). The reason for long indwelling time was reported in 25 cases; these reasons included "patient unaware stent needed to be removed" (17 cases), pregnancy (2 cases), other comorbidities (3 cases), and patient incarceration (3 cases). In 3 cases, the stent had become encrusted within 3 months of placement. Mean operative time was 162 minutes (±71). There were no major intraoperative complications, and no patients required blood transfusion. Litholapaxy was required for bladder coil encrustations in 22 cases (58%), and ureteroscopy with lithotripsy was required for encrustation of the ureteral portion of the stent in 13 cases (34.2%). Second look percutaneous procedures were required in 13 cases (34.2%). The stent was removed at the time of PCNL without need for concomitant or delayed ureteroscopy and/or cystolitholapaxy in 8 cases (21%). Ultimately, all stents were removed successfully. Patients were rendered stone free according to radiographs in 24 cases (63%). CONCLUSIONS: In this multicenter review, PCNL is confirmed to be a safe and effective means of addressing the retained and encrusted ureteral stent. PCNL without ureteroscopy or litholapaxy was sufficient in a minority of cases (21%). Adjunctive endourologic modalities are often required, and the surgeon should anticipate the need for concomitant antegrade ureteroscopic laser lithotripsy and/or cystolitholapaxy. Although complete stent removal can be anticipated, residual fragments are not uncommon.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".