Neurosurgical Catheters: What Silicone Means as a Material
Why neurosurgical catheters are made of silicone: what the material offers, how it affects handling and imaging, and what it does not decide on its own.
Silicone elastomer is soft, flexible and long established in implanted CSF devices, and it is the material of all six DESU neurosurgical catheter kits. In practice the material shapes how a catheter is handled, placed and seen on imaging. It does not, by itself, decide the clinical result.
Key takeaways
- All six DESU neurosurgical catheter kits use radiopaque silicone catheters with tantalum length marks.
- Softness and flexibility are the main benefits; the same softness is why placement aids and connectors matter.
- Biocompatibility belongs to the finished device, so the word “silicone” alone does not settle a comparison.
- Antibiotic-impregnated DESU catheters are silicone too, with the same dimensions as the standard versions.
Clinical decisions belong to the surgeon and the instructions for use (IFU). For definitions of catheter types and specification terms, see the neurosurgical catheter glossary.
What is silicone elastomer?
Silicone elastomer is a synthetic rubber built on a backbone of silicon and oxygen atoms, unlike the carbon backbone of most plastics. Formed into tubing and cured, it gives a soft tube that bends easily and returns to its shape.
“Silicone” on a catheter specification means a material made and controlled for medical use. It should not be confused with the element silicon or with household silicone products.
Why is silicone used for CSF catheters?
A CSF catheter has to pass from the ventricles or the lumbar space through soft tissue and stay in place for a long time, in the case of a shunt often for years. Several properties of silicone suit that job:
- Softness: a flexible tube can follow its route through tissue and move with the patient.
- Flexibility over a long length: the peritoneal catheter in a DESU kit is 120 cm long and has to stay pliable along all of it.
- Stability: silicone is relatively inert, which suits long contact with CSF and body tissue.
- Manufacturing control: it can be formed to precise inner and outer diameters and have drainage holes made along its tip section.
None of this is unique to one manufacturer. Silicone has been the usual material for CSF shunt tubing for decades, which is why a specification sheet rarely has to justify it. The more useful questions concern how a particular catheter is made and documented.
Does “biocompatible” silicone settle the question?
No. Biocompatibility describes a finished device, and the name of a raw material does not establish it. Under the ISO 10993 series, a manufacturer evaluates the device as it is supplied, which takes in the material, any additives, the processing and the sterilisation method.
For a buyer, this means that two catheters both described as silicone are not automatically equivalent. Dimensions, markings, hole pattern, kit contents and the supporting documents all need to be compared directly.
What does the material ask of the surgical team?
The softness that makes silicone useful also shapes how it is handled:
- Guidance during placement: a soft tube cannot push itself through tissue. The DESU ventricular catheter kit therefore includes a stylet, and the lumbar catheter kit includes a 14 G Tuohy needle and guidewire.
- Kinking: flexible tubing can kink at a sharp bend. The L-type catheter connector guides a ventricular or peritoneal catheter without kinking or clogging, and it is included in shunt kits as the right-angled connector.
- Mechanical care: soft tubing can be damaged by sharp instruments or a tie that is too tight, so connections and securing follow the IFU.
- Cleanliness: silicone surfaces tend to attract lint and fine particles, so catheters are usually kept away from materials that shed fibres until they are placed.
How does silicone show up on imaging?
Unmodified silicone is hard to see on a plain X-ray, so position would be difficult to confirm without further help. DESU catheters are radiopaque silicone, so their position can be followed under imaging. They also carry tantalum length marks: from 5 to 15 cm on the ventricular catheter and from 5 to 20 cm on the peritoneal, lumbar and lumbar drainage catheters.
The marks are a separate feature with their own uses, explained in our article on tantalum length marks and radiopacity.
How do DESU silicone catheters differ if the material is the same?
Geometry does the rest. The wall figure in the table is half the difference between outer and inner diameter, and it shows how the same material is used in different proportions.
| Silicone catheter | Inner diameter | Outer diameter | Calculated wall | Length |
|---|---|---|---|---|
| Ventricular | 1.3 mm | 2.5 mm | 0.6 mm | 23 cm |
| Peritoneal | 1.1 mm | 2.5 mm | 0.7 mm | 120 cm |
| Lumbar | 0.8 mm | 1.6 mm | 0.4 mm | 100 cm |
| Lumbar drainage | 0.8 mm | 1.6 mm | 0.4 mm | 80 cm |
The ventricular and peritoneal dimensions are the same across the Defit, Decurve and Depus VP shunt kits, so a team that knows the catheters in one kit already knows those in the others.
Is an antibiotic-impregnated catheter still silicone?
Yes. In DESU antibiotic-impregnated catheters the antibiotic is impregnated into the material and released in a controlled manner over 28 days. Both versions have the same diameters, length and tantalum marks, and both are silicone. The visible difference is colour: impregnated catheters are orange and standard ones white.
What does silicone not decide?
Choosing silicone does not, on its own, prevent blockage, infection, overdrainage or underdrainage. Those depend on the patient, the surgical technique, the valve or drainage system and the care that follows. The catheter type, route and system remain the surgeon’s decision, made with the IFU.
Talk to a DESU product specialist
If you are comparing catheter specifications or need documentation for a review, our product specialists can help. Write to sales@desu.tr, use the contact page, or request a quote.
Frequently asked questions
Is the shunt valve made of silicone too?
It depends on the family. Defit is a silicone valve, Decurve combines polypropylene and silicone elastomer, and Depus has a polysulfone valve. The catheters in these kits are silicone.
Are tantalum marks part of the silicone?
They are separate. Silicone is the catheter material and tantalum is the marking material.
Should a buyer ask for anything beyond the word silicone?
Yes. Ask for the dimensions, the length-mark range, the drainage hole pattern, the kit contents, and the quality and biological evaluation documents for the finished device.
Related standards
- ISO 10993 series: Biological evaluation of medical devices
- ISO 7197: Neurosurgical implants — Sterile, single-use hydrocephalus shunts and components