FDA 510(k) Search - By Innolitics (SaMD and AI Experts)

The Microvasive® Temporary Ureteral Drainage Stent is 6 Fr x 26.5 cm, with an open-ended coil at each end. The stent is an extruded polymeric tube made of a reversible cross-linked alginate polymer with an incorporated radiopacifier. The device is placed, using standard ureteral stent placement techniques that can be placed transurethrally, percutaneously or via open surgery using endoscopic and/or radiographic techniques.

AI/ML Overview

Here's an analysis of the acceptance criteria and study details for the Boston Scientific/Microvasive Temporary Ureteral Drainage Stent (TUDS) based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance:

Acceptance Criteria Category	Specific Metric	Acceptance Criteria (Implied/Direct)	Reported Device Performance (TUDS)
Effectiveness	Primary Effectiveness Endpoint: Study Success	"adequate short term drainage defined as the presence of the stent in the ureter and the lack of surgical or other intervention to treat symptoms on the stented side during the first 48 hours following placement." (The exact quantitative hurdle for "acceptable" isn't explicitly stated but the performance against it is given as the study outcome.)	78.2% (68/87). (17 absence of stent and 3 interventions occurred within the first 48 hours; 1 patient had both an absence of stent and intervention.)
	Alternate Endpoint: Overall Clinical Success (90-day follow-up)	"adequate drainage with no intervention (regardless of stent presence) and no definitely device-related serious adverse events (SAEs) throughout the 90 day follow-up period." (Again, the quantitative threshold for "acceptable" isn't explicitly stated, but the performance against it is given.)	94.3% (83/88) with the 90-day study period.
Safety	Primary Safety Endpoint: Assessment of Adverse Events	"Assessment of adverse events (incidence, relationship to device, severity)" compared to published clinical studies of plastic ureteral stents. (The implicit criteria is that adverse event profiles should be comparable or improved, and there should be no unanticipated events.)	No unanticipated adverse events reported. All adverse events resolved by the end of the study without any permanent sequelae. Key findings include:

Flank pain/loin discomfort: 12.5% (11/88)
Hydronephrosis: 3.4% (3/88)
Suprapubic pain/lower abdominal pain: 8% (7/88)
Urinary frequency: 51.8% (44/85) at day 1
Urinary urgency: 67% (59/88) at baseline
Urethral discomfort: 27.9% (24/86) at day 1
Stent migration: 19.5% (17/87) (but only 3.4% required intervention)
Additional stent specific procedures: 3.4% (3/88) through 48 hrs; 8.0% (7/88) through 90 days. |
| Device Characteristics | Successful Placement | Not an explicit acceptance criterion, but a measure of initial procedural success. | 98.9% (88/89) (1 patient required 2 stents). |
| | Time to eliminate TUDS from ureter | Not an explicit acceptance criterion, but a characteristic of the device. | Mean = 13.0 (±11.3) days, Median = 8 days. |
| | Time to eliminate TUDS from body | Not an explicit acceptance criterion, but a characteristic of the device. | Mean = 21.0 (±17.8) days, Median = 15 days. |
| | Retained stent fragments at 90 days in renal pelvis | Not an explicit acceptance criterion, but a safety concern. | 3.4% (3/87). (Of these, 2 had successful ESWL, 1 declined intervention and was asymptomatic). |
| | Tolerability (Moderate to most severe pain) | Not an explicit acceptance criterion, but a measure of patient experience. | Day 1: Flank pain - 23.0% (20/87), Urethral pain - 27.9% (24/86).
Day 30: Flank pain - 8.7% (7/80), Urethral pain – 2.5% (2/80). |
| | Patient Satisfaction | Not an explicit acceptance criterion, but a measure of patient experience. | 88.8% satisfied (71/80). |

2. Sample Size Used for the Test Set and Data Provenance:

Sample Size: 88 patients were enrolled and had the TUDS placed. 87 were evaluable for the "Study success" endpoint, and 88 for "Overall clinical success."
Data Provenance: The study was a prospective, single-arm, multi-center trial conducted across 6 investigative sites. The text does not specify the country of origin, but "Boston Scientific/ Microvasive, One Scientific Place, Natick, MA" suggests a US-based sponsor, and "FDA's Draft Guidance Ureteral Stents was utilized" (Section V), and the FDA 510(k) submission and approval letter, strongly imply the study was conducted to satisfy US regulatory requirements, likely within the US or under clinical trial regulations accepted by the FDA.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:

The study involved clinical assessments by medical professionals at various investigative sites (6 sites). These assessments included device presence, position, morphology (via KUB films), and evaluation of adverse events. Also, normal renal function was assessed by Intravenous Pyelogram (IVP) at 30 days.
The document does not explicitly state the number or specific qualifications of individual experts (e.g., radiologists, urologists) who established the "ground truth" for each patient's condition or imaging interpretation. The data comes from direct clinical observations, imaging results (KUB, IVP) interpreted by clinical staff at the study sites, and formal capture of adverse events by the investigators.

4. Adjudication Method for the Test Set:

The document does not describe a formal adjudication method (e.g., 2+1, 3+1, none) for the test set. Clinical outcomes, imaging results, and adverse events were presumably recorded by the treating physicians/staff at each center and then collected and analyzed by the study sponsor. There is no mention of independent expert review or a consensus panel.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:

No, an MRMC comparative effectiveness study was not done. This was a single-arm study evaluating the safety and effectiveness of the TUDS device in facilitating short-term drainage. It did not involve comparing human readers' performance with and without AI assistance.

6. Standalone (i.e., algorithm only without human-in-the-loop performance) Study:

Not applicable. This device (Temporary Ureteral Drainage Stent) is a physical medical device, not an algorithm or AI system. Therefore, the concept of "standalone algorithm performance" is not relevant. The study evaluates the performance of the physical stent in patients.

7. Type of Ground Truth Used:

The ground truth was established through a combination of clinical observation, diagnostic imaging (KUB films, Intravenous Pyelogram - IVP), and documented patient outcomes/adverse events.
- "Study success" relied on the presence of the stent in the ureter (observable via KUB) and the absence of surgical or other intervention for symptoms.
- "Overall clinical success" relied on adequate drainage (clinical judgment, potentially supported by imaging) and the absence of device-related serious adverse events documented through follow-up.
- Adverse events were based on clinical assessments and patient reporting during follow-up visits.
- Stent presence/position/morphology was assessed via radiological assessments (KUB films).
- Normal renal function was assessed by IVP.

8. Sample Size for the Training Set:

Not applicable. As this is a study for a physical medical device and not an AI/ML algorithm, there is no "training set" in the context of machine learning. The study itself served as the primary clinical evidence for regulatory submission.

9. How the Ground Truth for the Training Set Was Established:

Not applicable. (See point 8).

Summary

Regulation Number and Section

§ 876.4620 Ureteral stent.

(a)
Identification. A ureteral stent is a tube-like implanted device that is inserted into the ureter to provide ureteral rigidity and allow the passage of urine. The device may have finger-like protrusions or hooked ends to keep the tube in place. It is used in the treatment of ureteral injuries and ureteral obstruction.(b)
Classification. Class II (performance standards).