Ureteral Access Sheath Deployment: How Much Force Is Too Much? Initial Studies with a Novel Ureteral Access Sheath Force Sensor in the Porcine Ureter
Bibliographic record
Abstract
Introduction and Objectives: Ureteral injuries can occur during ureteral access sheath (UAS) deployment. The force exerted during deployment and the amount of force that results in ureteral injury is yet to be accurately quantitated. In this feasibility study, we developed and then tested a novel force-sensing device in our animal laboratory to identify the threshold force that results in a porcine ureteral injury. Methods: With Institutional Animal Care and Use Committee approval, we measured ureteral dilator and UAS deployment force using our proprietary University of California, Irvine Ureteral Access Sheath Force Sensor (UAS-FS). The exerted force was measured during deployment from the moment that the tip of the UAS was passed into the urethral meatus until it reached the renal pelvis; progression of the UAS along the ureter was monitored with fluoroscopy. Ureteroscopic evaluation was performed after deployment of each catheter/sheath ≥8F to assess for ureteral injury using the Postureteroscopic Lesion Scale (PULS). Results: Six juvenile Yorkshire female pigs (12 ureters) were studied. No injuries were detected when the deployment force was <4 Newtons (N), which was the case when the catheter/access sheath was ≤13F. Increasing UAS size >13F resulted in greater peak forces. In five of the pigs, ureters selected for 14F UAS deployment without previous sequential dilation were injured (PULS ≥3) at a mean threshold force of 4.84 N. Serial dilation had a higher threshold for PULS ≥3 at 5.56 N. Overall, injury of PULS ≥3 was routinely noted when the force applied exceeded 8.1 N. Conclusions: The UAS-FS reliably measured forces while deploying a UAS. Significant ureteral injury can routinely be avoided if the applied force is <4.84 N; PULS ≥3 routinely occurred when forces exceeded 8.1 N. Serial dilation may allow safe passage at higher deployment forces, as much as 5.56 N.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".