Model note · CSF Shunt
Medtronic StrataMR II adjustable pressure valve and shunt
StrataMR II is Medtronic's current adjustable hydrocephalus valve, the successor to the widely implanted Strata II. A ball and cone valve sits in series with a normally closed siphon control diaphragm, and the surgeon selects one of five performance levels through the skin with magnetic tools, without needing an X-ray to confirm. Its MRI resistance mechanism requires the rotor to be lifted then turned, so stray fields up to 3 T should not change the setting.
The model
Maker, model and type.
- Maker
- Medtronic Neurosurgery (Medtronic, Inc.)
- Model
- StrataMR II adjustable pressure valve and shunt (small 42955MR, regular 42965MR)
- Device type
- CSF Shunt
- Main document
- Open the public document
Key specifications
What the public record says.
| Item | Value | Source |
|---|---|---|
| Performance levels | 5 discrete levels, 0.5, 1.0, 1.5, 2.0 and 2.5 | Source |
| Approximate pressure, horizontal, from brochure chart | About 25 mmH2O at level 0.5 up to 145 mmH2O at level 2.5 | Source |
| Approximate pressure, vertical, from brochure chart | About 37 mmH2O at level 0.5 up to 157 mmH2O at level 2.5 | Source |
| Valve size, maximum dimensions | Small 1.93 x 0.59 x 0.37 in; regular 2.29 x 0.70 x 0.42 in (L x W x H) | Source |
| Adjustment tools | Locator, guider, indicator and adjustment tools (kit 45909SMR), cleared under K181622 | Source |
| MRI resistance | Designed to resist setting changes from external magnets including MRI up to 3.0 T | Source |
| Sterilisation and shelf life | Ethylene oxide; 22 months | Source |
| FDA clearance | K212641, product code JXG, Class II | Source |
Recalls
Recalls.
This note lists no recalls. Check the FDA recall database for the latest record.
Safety
Safety warnings from the record.
- A valve set in the wrong orientation runs at higher pressure, and untreated underdrainage can progress to coma or death. Source
- Older Strata II and Strata NSC valves (not StrataMR) can develop a reversed magnet after 3 T exposure combined with debris, so tool readings may be wrong. Source
- Read the device manual's MRI information before scanning; the brochure states it does not replace the manual. Source
Sources
Where this note comes from.
- FDA 510(k) K212641 summary, StrataMR II Valves and Shunts
- Medtronic StrataMR II brochure (EMEA, 2024)
- FDA recall Z-1702-2017, StrataMR locator tool misalignment (earlier StrataMR valve)
- HSA Singapore notice: Strata II/Strata NSC valve magnet reverse polarity, Feb 2017
- openFDA MAUDE problem counts, brand StrataMR
Not covered: No FDA recall record names StrataMR II itself; the locator tool recall applies to the earlier StrataMR, so it is cited only as background and not listed as a recall. Pressure values are read from brochure charts and are approximate; the full instructions for use with tolerances and MRI conditions were not reachable (Medtronic's site blocked automated access). MAUDE figures are for brand StrataMR and may mix both generations. Implanted valves have no error codes.
BMEssentia knowledge drafted from public information, reviewed by Hasan Khaled Ismail on 2026-10-24. Always follow the manufacturer's instructions for use and service manual.
CSF Shunt