A New Twist on an Old Technique: Lawson Retrograde Endoscopic-Guided Nephrostomy Access for Percutaneous Nephrolithotomy in Prone Split-Leg Position
Bibliographic record
Abstract
Background: A minority of urologists performing percutaneous nephrolithotomy (PCNL) achieve their own nephrostomy access. In an effort to simplify the access part of PCNL, we herein describe our initial experience with endoscopic-guided retrograde percutaneous access in the prone split-leg position. Case Presentation(s): After informed consent, a confirmed negative urine culture, and 1 week pretreatment with tamsulosin, four carefully selected PCNL patients underwent endoscopic-guided retrograde access in a prone split-leg position using the Lawson catheter. In all the four patients, we achieved endoscopic-guided retrograde upper pole access in the prone split-leg position. A single Clavien 3B complication occurred. Total fluoroscopy time for the PCNL averaged 162 seconds (51–283). Complete stone-free rate at 1 week based on CT scan was 25%, and a stone-free rate defined as <4 mm was 100%. Conclusion: Endoscopic-guided retrograde percutaneous upper pole access can be established efficiently with a modified Lawson technique in the prone split-leg position.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.003 |
| Scholarly communication | 0.002 | 0.005 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.003 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".