Written and maintained by CASRAI Editorial Board
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General product and use information only, drawn from the sources listed below. This page is not medical advice and does not describe any procedure; decisions about an individual patient belong to the treating clinician.
Short answer
A JJ stent, also written double-J stent, is a ureteral stent: a small, flexible, tube-like implant that runs from the kidney to the bladder so urine can keep draining. In the United States it is a Class II medical device regulated under 21 CFR 876.4620 (FDA product code FAD). Urologists commonly use one around ureteroscopy, the scope-based procedure used for kidney stones.
Definition and scope
The FDA regulation defines a ureteral stent as a “tube-like implanted device that is inserted into the ureter” to provide ureteral rigidity and allow the passage of urine. The regulation adds that the device may have finger-like protrusions or hooked ends to keep the tube in place. The Cochrane review of stenting after ureteroscopy describes the same thing in clinical terms: a small, flexible tube placed from the kidney to the bladder. A 2020 study in the Journal of Urological Surgery uses “Double-J (JJ) stent” as the working name for this device, so JJ stent, double-J stent and ureteral stent refer to the same category of product in clinical literature.
What a stent looks like in practice, including its curled ends and the French and length ranges one manufacturer offers, is covered in ureteral stent sizes and the size chart. This page deliberately does not repeat that chart; it covers what the device is for, the related terms people mix up, and where it sits in regulation and supply.
How does a stent work for kidney stones?
The stent does not dissolve or remove a stone. Its job is drainage: according to the Cochrane review, stents keep urine moving from the kidney to the bladder even if the ureter becomes obstructed afterwards. MedlinePlus says the surgeon may place a stent after ureteroscopy “to allow urine and small pieces of kidney stone to pass through.”
The same sources are candid about the trade-off. Cochrane lists stent-related symptoms, including urinary frequency and urgency, blood in the urine and painful urination, as the most common cause of postoperative morbidity. MedlinePlus notes that people with a stent may feel side pain, especially during or just after urination.
What is ureteroscopy and what is it used for?
Ureteroscopy uses a small tube, rigid or flexible, with a tiny light and camera on the end, so the surgeon can look inside the ureters. MedlinePlus lists these uses: removing kidney stones or breaking them with a laser, checking for cancer, examining or removing growths, and evaluating narrowed areas. The scope is the instrument; the stent is the implant that may be left behind afterwards. They are different products with different supply lines.
Stent string: what it is
Some stents are made with an extraction string attached. The 2020 Journal of Urological Surgery study compared two removal techniques in 177 patients after ureteroscopic stone surgery, and its abstract states that most urologists prefer to use a double-J stent without an extraction string. The study reports that the total cost of surgery was 28.5 percent higher in the cystoscopic-removal groups than in the manual-removal groups, and its authors concluded that removal with an extraction string is a reliable method with low treatment costs. It is one study, so treat it as one data point.
Regulatory identity: matching a catalogue item to the rule
Because the same product appears under several names, the regulatory identifiers are the most reliable way for clinic and supply staff to confirm they are talking about the same device.
| Identifier | Value | Source |
|---|---|---|
| Regulation | 21 CFR 876.4620, ureteral stent | eCFR, checked 2026-10-30 |
| Classification | Class II (performance standards) | eCFR, checked 2026-10-30 |
| FDA device name and product code | Stent, Ureteral; FAD | openFDA device classification, checked 2026-10-30 |
For how device classes and quality-system rules fit together, see CASRAI’s guide to 21 CFR Part 820 and the dictionary entry on FDA De Novo classification.
Where it matters for labs, clinics and supply decisions
- Use the identifiers, not the nickname. JJ, double-J and ureteral stent are the same category; the regulation number and product code above are what a record should carry.
- Stent and scope are separate items. A urology setup lists both; see the urology clinic supply checklist for the wider consumables list.
- Stenting is a clinical decision, not a default. The Cochrane review of stent versus no stent after ureteroscopy found desirable and undesirable effects that were small in absolute terms, with findings based mostly on low and very low certainty evidence.
- A different drainage device. A stent sits inside the ureter; external drainage hardware is a separate topic covered in nephrostomy tube parts.
Common misunderstandings
- “A stent treats the stone.” It supports drainage; stone removal or fragmentation is done by the ureteroscopy itself (MedlinePlus).
- “Ureteroscopy and a stent are the same thing.” One is a procedure with a scope, the other is an implant that may be left in afterwards.
- “Every ureteroscopy includes one.” Cochrane found small effects on low-certainty evidence either way, so use of a stent is a clinical decision.
FAQ
What does a stent look like?
It is a small, flexible, tube-like device (FDA regulation wording) that runs from the kidney to the bladder (Cochrane), and the regulation notes it may have finger-like protrusions or hooked ends. Its curled ends and typical dimensions are described in the ureteral stent sizes guide.
How does a stent work for kidney stones?
It keeps a channel open so urine and small stone pieces can pass from the kidney to the bladder; it does not itself remove the stone.
What is ureteroscopy and what is it used for?
Looking inside the ureters with a small scope to remove or laser-break stones, check for cancer, examine or remove growths, and evaluate narrowed areas.
What are ureteral stent sizes and lengths?
Sizes are given in French and millimetres; the full chart is on the sizes page.
What is a stent string?
A string attached to some stents. A 2020 Journal of Urological Surgery study states that most urologists prefer to use a double-J stent without one; its authors concluded that removal with an extraction string is reliable with low treatment costs.
Sources
- 21 CFR 876.4620, Ureteral stent. eCFR, checked 2026-10-30. ecfr.gov
- openFDA device classification, product code FAD (Stent, Ureteral, class 2). Checked 2026-10-30. api.fda.gov
- MedlinePlus, Ureteroscopy (review date 7/1/2025). Checked 2026-10-30. medlineplus.gov
- Ordonez M, Hwang EC, Borofsky M, Bakker CJ, Gandhi S, Dahm P. Ureteral stent versus no ureteral stent for ureteroscopy. Cochrane Database Syst Rev 2019;(2):CD012703. Checked 2026-10-30. PMC6365118
- Çınar Ö, Bolat MS, Öztürk K. Should the Double-J Stent Be Removed Endoscopically after a Ureteroscopic Stone Surgery? Journal of Urological Surgery, 2020. Checked 2026-10-30. DOAJ record
